TSI...INTERNATIONAL CONFERENCE ORGANISED BY Transport and Telecommunication Institute (Latvia) The...

Transporta un sakaru institūts (Transport and Telecommunication Institute)

Transport and

Telecommunication

Volume 6, No 2 - 2005

ISSN 1407-6160

Riga – 2005

EDITORIAL BOARD: Prof. Igor Kabashkin (Editor-in-Chief), Transport & Telecommunication Institute, Latvia Prof. Irina Yatskiv, Transport & Telecommunication Institute, Latvia Prof. Adolfas Baublys, Vilnius Gedeminas Technical University, Lithuania Dr. Brent Bowen, University of Nebraska at Omaha, USA Prof. Olgierd Dumbrajs, Helsinki University of Technology, Finland Prof. Arnold Kiv, Ben-Gurion University of the Negev, Israel Prof. Anatoly Kozlov, Moscow State University of Civil Aviation, Russia T&T Personnel: Literary editor – Lucija Paegle Technical editor – Irina Mihnevich Host Organizations: Transport and Telecommunication Institute, Latvia – Eugene Kopytov, Rector Telematics and Logistics Institute, Latvia – Igor Kabashkin, Director Co-Sponsor Organization: PAREX Bank, Latvia – Valery Kargin, President Supporting Organizations: Latvian Transport Development and Education Association – Andris Gutmanis, President Latvian Academy of Sciences – Juris Ekmanis, President Latvian Operations Research Society – Igor Kabashkin, President Telecommunication Association of Latvia – Janis Lelis, Executive Director Articles and review are presented in the journal in English (preferably), Russian and Latvian (at the option of authors). EDITORIAL CORRESPONDENCE Transporta un sakaru institūts (Transport and Telecommunication Institute) Lomonosova iela 1, LV-1019, Riga, Latvia. Phone: (+371)-7100594. Fax: (+371)-7100535. E-mail: [email protected], http:// www.tsi.lv TRANSPORT and TELECOMMUNICATION, 2005, Vol. 6, No 2 ISSN 1407-6160 The journal of Transport and Telecommunication Institute (Riga, Latvia). The journal is being published since 2000.

Copyright © Transport and Telecommunication Institute, 2005

iii

CONTENTS

International Conference RELIABILITY and STATISTICS in TRANSPORTATION and COMMUNICATION (RelStat’04), 14–15 October 2004, Riga, Latvia

PROGRAMME of the International Conference RelStat’04 ..........................................208

Proceedings. Part 2 .......................................................................................................212

Conference Authors Index ............................................................................................332 Cumulative Index ..................................................................................................................334

iv

International Conference

RELIABILITY and STATISTICS in TRANSPORTATION and COMMUNICATION

(RelStat’04)

14–15 October 2004, Riga, Latvia

PROCEEDINGS

Part 2

Igor V. Kabashkin (ed.)

Riga – 2005

Proceedings of the International Conference RELIABILITY and STATISTICS in TRANSPORTATION and COMMUNICATION (RelStat’04), 14–15 October 2004, Riga, Latvia, in 3 Parts. – Riga: Transport and Telecommunication Institute, 2005, Part 2. 140 p. ISBN 9984-668-85-1 The aim of the journal is to acquaint the readers with the national experience and research activities of various countries in the fields of transport and telematics as well as with the working materials of the European thematic networks and the research projects in this area. This special edition is devoted to the International Conference "Reliability and Statistics in Transportation and Communication" (October 14–15, 2004, Riga, Latvia). The edition includes texts of conference reports written by the authors in a special journal version. The authors have submitted the material in English or Russian in accordance with the official languages of the Conference. Therefore, for the convenience of readers the editorial board has divided the selected materials into three editions – English (Vol.6, No1, No2, 2005) and Russian (Vol.6, No3, 2005). ISBN 9984-668-85-1

Copyright © Transport and Telecommunication Institute, 2005

INTERNATIONAL CONFERENCE ORGANISED BY

Transport and Telecommunication Institute (Latvia) The Kh. Kordonsky Charitable Foundation (USA)

in co-operation with

Latvian Transport Development and Education Association (Latvia) Latvian Operations Research Society (Latvia)

Latvian Academy of Science (Latvia)

THE PROGRAMME COMMITTEE

Prof. Adolfas Baublys, Vilnius Gedeminas Technical University, Lithuania Dr. Brent Bowen, University of Nebraska at Omaha, USA Prof. Igor Kabashkin, Transport & Telecommunication Institute, Latvia Prof. Eugene Kopytov, (Chairman) Transport & Telecommunication Institute, Latvia Prof. Anatoly Kozlov, Moscow State University of Civil Aviation, Russia Prof. Zohar Laslo, Sami Shamoon College of Engineering, Israel Prof. Lauri Ojala, Turku School of Economics and Business Administration, Finland Prof. Irina Yatskiv, Transport & Telecommunication Institute, Latvia Prof. Edmundas Zavadskas, Vilnius Gediminas Technical University, Lithuania

ORGANIZATION COMMITTEE

Prof. Igor Kabashkin, Latvia – Chairman Mrs. Inna Kordonsky-Frankel, USA – Co-Chairman Prof. Irina Yatskiv, Latvia – Co-Chairman Mrs. Elena Rutkovska, Latvia – Secretary

208

PROGRAMME of the International Conference

“RELIABILITY and STATISTICS in TRANSPORTATION and COMMUNICATION (RelStat’04)”

14–15 October 2004, Riga, Latvia

Thursday, October 14 Transport and Telecommunication Institute (Lomonosova 1, Aud. 703)

Registration

Discussion Panel 1. Development of Transport Logistics in the Baltic States • Intermodal Portal System. Igor Kabashkin (Latvia, Transport and Telecommunication

Institute) • Interfaces Between Logistics Centres and Lithuanian Economical Development.

Ramunas Palsaitis, Gintautas Labanauskas (Lithuania, Vilnius Gediminas Technical University)

• The Development and Perspectives of Logistics Centres in Lithuania. Ieva Meidute (Lithuania, Vilnius Gediminas Technical University)

• The Role and Place of Logistic Centre under the Contemporary Conditions. Alexander Medvedev, Vladimir Zvonarev (Latvia, Transport and Telecommunication Institute)

Discussion Panel 2. Innovative Vocational Education and Training in Transport Area

(It is organized within the frame of European Project IVETTA) • The Main Goals and Programme of European Project IVETTA. Gregory Gudkin

(Latvia, Riga Managers School) • A Network for Transport Training and Education. Igor Kabashkin (Latvia, Transport

and Telecommunication Institute) • Transport Education and Training in Vilnius Gediminas Technical University.

Ramunas Palsaitis (Lithuania, Vilnius Gediminas Technical University)

Friday, October 15 Maritim Park Hotel Riga (Slokas Street 1)

Registration

Opening Session (Hall "Berlin"). Session Chair – Igor Kabashkin (Latvia, TTI) • Professor Kordonskiy – Teacher and Educator. Oleg Schiptsov (Latvia, Transport and

Telecommunication Institute)

Plenary Session (Hall "Berlin"). Session Chair – Igor Kabashkin (Latvia, TTI) • Decision Support Systems in Lithuania. E.K.Zavadskas, A.Kaklauskas, S.Raslanas

(Lithuania, Vilnius Gediminas Technical University) • Status of Transport Sector Restructuring in the Baltic States. Cesar Queiroz (Finland,

The World Bank), Lauri Ojala, Tapio Naula (Finland, The Turku School of Economics and Business Administration)

• About Some Models of Inventory Control for Transport Company. Eugene Kopytov, Leonid Greenglaz (Latvia, Transport and Telecommunication Institute)

209

Time Hall #1 Hall #2 Hall #3 Hall #4 Hall #5 Session 1

Transport Economics Session 2

Statistical Applications Session 3

Transport and General Management

Session 4 Reliability of Aviation and

Mechanical Systems

Session 5 Efficiency of Electronics

Systems and Devices 11:30–13:30 Session Chair –

Ramunas Palsaitis Session Chair – Irina Yatskiv

Session Chair – Alexander Pankov

Session Chair – Olegas Prentkovskis

Session Chair – Valery Kutev

Maximum Level of the Automobilization of Cities. Alexander Stetjuha (Latvia) The Economic and Financial Appraisal for Phase 1 of the Rail Baltica Project. Jonas Jonaitis (Lithuania) Contemporary Requirements of the Effective Realization of Logistic Systems. Inta Laurena, Alexander Stetjuha (Latvia) Analysis of the Influence of the New System of VAT Taxation and Its Impact on the Work of Transportation Companies Working on the EU Market. Michael Litvinenko (Lithuania) Impact of Market Liberalization to the Passengers’ Transportation by Rail in Lithuania. Jonas Butkevičius, Ramunas Palsaitis (Lithuania) Comparability of the Prime Cost of Transportation in Different Forms of Transport During the Solution of the Logistic Problems. Stetjuha Alexander, Natalia Trezkova (Latvia)

Regression Models for Forecasting of Traffic Flow in Decision Support System on the Latvian Railway. Vasily Demidov, Yury Bogdanov (Latvia) The Methods of Checking the Results of the Iterative Classification. Lada Gusarova, Irina Yatskiv (Latvia) The Variance-Free Characterization of Heteroscedastic Normal Variables with an Application in Financial Econometrics. Max Moldovan (Latvia) Statistical Decision Equivalence Principle and Its Applications. Nikolas Nechval, Konstantin N. Nechval, Edgars K. Vasermanis

(Latvia) Resampling Median Estimators for Linear Regression Model Parameters. Helen Afanasyeva (Latvia) Development of Information Portal for the Purpose of the Creation of the Reference Book of a Range of Statistical Distribution and Make Use of Portal Funds for the Training Process. Liumkis Victor, Alexey Churko, Alexander Bychkov (Latvia)

Financial Risk of Providing the Universal Telecommunications Service in Latvia. Irina Klevecka, Janis Lelis (Latvia)

Activity-Planning Model of a Transport Company. Daiva Novikoviene (Lithuania)

Corruption in Logistic Chain and its Processes. Jonas Lazauskas (Lithuania)

Evaluation of the Influence of the Rate of Discount on the Competitive Capacity of Enterprises.Eduard Fedchuk (Latvia) Benchmarking Needs in Lithuanian Transport Analysis. Margarita Išoraitė (Lithuania)

Coordination of the Reliability of the Planning Solutions at Two Levels. Arnoldina Pabedinskaite (Lithuania)

Statistical Imitation Forecast Models of the Estimations of the Wear of the Bandages of Locomotives’ Wheels Pair. Leonas Povilas Lingaitis, Sharunas Mikaliunas, Valentinas Podvezko (Lithuania) The Influence of Corrosion on Reliability and Inspection Program for Fatigue – Prone Airframe Structures. M. Shujauddin Wahab, Yu.M.Paramonov (Latvia) The Estimation of the Effectiveness of the Program of the Airships’ Maintenance and Repair. Smolakova Natalia, V. Shkutan, V. Shestakov (Latvia) Statistical Investigation of the Fatigue Crack Propagation Process. Konstantin Nechval (Latvia) The Simulation of Dynamic Processes in the Mechanical and Pneumatic System. Marijonas Bogdevičius (Lithuania) The Influence of Material Dosing Parameters on the Accuracy and Stability of the Produced Asphalt Concrete Mixture Composition. Henrikas Sivilevičius (Lithuania)

Synthesis of Highly Selective Digital Filters According to the Frequency and Time Characteristics. V.Yeremeyev, D. Sipchenko, S. Sharkovsky (Latvia) Simulation of the Emission of the Arched Antenna Lattice of the System’s Base Station of the Mobile Communications. Dmitry Krasikov (Latvia) Characteristics’ Identification of Narrow-Band Discrete Systems V.Yeremeyev, Т. Mamirov (Latvia) Analysis of Methods and Means of the Single-Position Passive Radar of the Center of Thunderstorms. Truskovsky Pavel (Latvia) Efficiency Increasе of Short Wave Communication Lines in Civil Aviation. A.J.Mrochko, Yu.M. Sikerzhitski, V.A. Shelkovnikov (Latvia) Special Features of Radiowave Propagation in the Waveguide the Earth–Ionosphere. Julia Goncharova (Latvia)

210

Time Hall #1 Hall #2 Hall #3 Hall #4 Hall #5

Session 6 Transport

Session 2 Statistical Applications

Session 3 Transport and General

Management

Session 4 Reliability of Aviation and

Mechanical Systems

Session 5 Efficiency of Electronics

Systems and Devices 14:30-16:30 Session Chair –

Adolfas Baublys Session Chair –

Alexander Andronov Session Chair – Igor Kabashkin

Session Chair – Yury Paramonov

Session Chair – Michael Zilberman

Possibility of Passengers Intermodality in Lithuania. Daiva Griskevičiene, Algirdas Griskevičius (Lithuania) Control Model Development for the Needs of Urban Environment Monitoring Based on Mobile Airborne Multipurpose Center Application. Alexander Berezhnoy (Latvia) Model for the Comparison of Infrastructure Costs Caused by Use of Different Transport Modes. Aidas Vasilis Vasiliauskas (Lithuania) Procession Method Like Method that Helps to Manage Quality of Transport Services. Igor Petuhov (Latvia) Analysis of Vehicles Drivers' Speed on Accident Rates. Alvydas Pikūnas, Vidmantas Pumputis (Lithuania) The Development of the Transportation of Passengers by Lithuanian Sea Transport. Jonas Butkevičius, Andrius Vyskupaitis (Lithuania)

The Simulation of Road Transport Operation at the Terminal. Danute Bagdoniene, Skirmantas Mazura (Lithuania) Optimal Airline Seat Inventory Control for Multi-Leg Flights. Kristine Rozite, Nicholas A. Nechval, Edgars K. Vasermanis (Latvia) Application of Statistical Analysis of Traffic to Develop Lithuanian Road Network. Daiva Zilioniene, Antanas Aloyzas Juzenas, Kazys Petkevicius (Lithuania) Simulation of the Multi-Criterion Selection of the Contractor of the Maintenance of Buildings, Using the Theory of Games. Edmundas Zavadskas, Zenonas Turskis, Tatjana Vilutiene (Lithuania) Logistical Factors' Influence to the Transport Flows Distribution. Case Survey in Lithuania. Andrius Jarzemskis (Lithuania) Statistical Models for Checkpointing the Computer Systems. Edgars K. Vasermanis, Konstantin N. Nechval, Nicholas A. Nechval (Latvia) Objective and Subjective Evaluations of the Significance of Indices in the Multi-Criterion Models. Romualdas Giniavičius, Valentinas Podvezko (Lithuania)

Working Tools for the Director. Quality Management System. Georgy Utehin (Latvia) Development of Marketing Strategies in Lithuanian Transport Companies. Jonas Butkevicius, Andrius Vyskupaitis (Lithuania) Influence of the Non-Basic Indices of Management on the Estimation of the Interests of Participants in the Venture Investment. Rostislav Kopitov (Latvia) Heterogeneity of the Investment Space of Latvia. Denis Titarenko (Latvia) Model of Investment Evaluation of Public Building Based on Multiple Criteria Decision Synthesis Methods. Vaidotas Šarka, Edita Šarkienė, Saulius Budinas (Lithuania) Business-Plan as the Tool of Gratuitous Financing. Irina Litnitska (Latvia)

Modelling of Fatigue Life of Composite. Alexandra Paramonova, M.Kleinhofs, Yury Paramonov (Latvia) Simulation of the Impact of Mineral Materials' Homogeneity on the Stability of the Produced Asphalt Concrete Mixture. Henrikas Sivilevičius, Kęstutis Vislavičius (Lithuania) Analysis of Stability and Controllability of the Flight Vehicle for Dynamic Maintenance in Different Flight Conditions. V.Shestakov, I.Polencs (Latvia) Dynamics of the Vehicle in the Mode of Emergency Braking. Olegas Prentkovskis, Robertas Pečeliūnas (Lithuania) Use of a Method of the Functional-Steady Estimation of Systems with a Study of the Systems of the Glider of Air Vessel. V.Shkutan, V.Shestakov (Latvia) The Research on the Influence of the External Excitation Characteristics on the Dynamic "Man – Wheelchair – Vehicle" System. Mečislovas Mariūnas, Julius Griškevičius (Lithuania)

A Method to Increase the Number of Subscribers of Mobile Communications Networks. Natalya Bogomolova, Olga Denisieva (Russia), Andrejs Gobzemis (Latvia)

Estimation of Frequency Characteristics of Supernarrow-Band Filters. Tahir Mamirov (Latvia)

The Analysis of the Receiving Antennae Effectiveness. Shelkovnikov Vladimir (Latvia) Comparative Analysis of the Algorithms of Interaction of the Models of the Air Targets Motion. Michael Zilberman, Natalya Signeyeva (Latvia) On One Approach for Solutions of Two Nonlinear Heat Transport Problems Arising in the Catastrophe Theory. Sharif Guseinov (Latvia) On the Estimation of the Parameters of Power Impulse at the Input of Antenna According to Its Electromagnetic Radiation. J. Krasnitsky (Latvia) Chaotic Phenomena in Quantum Computing. Yuri Shunin, Victor Gopeyenko and Alexey Gopeyenko (Latvia)

211

Time Hall #1 Hall #2 Hall #3 Hall #4 Hall #5

Session 6 Transport

Session 1 Transport Economics

Session 7 Information Technology in

Transportation and Education

Session 8 Computing Mathematics

16:50-18:30

Session Chair – Vladimir Kuznecov

Session Chair – Alexander Stetjuha

Session 3 Transport and General

Management Session Chair –

Rostislav Kopitov Session Chair – Boriss Misnevs

Session Chair – Eugene Kopytov

Prospects for the Utilization of Unfit for the Operation Automobiles and Their Operational Materials in Lithuania. Alvydas Pikūnas, Valdas Valiūnas (Lithuania) Braking Effectivenss Research Dependence on Vehicles Weight. Valdas Valiunas, Aurelijus Vestartas (Lithuania) The Complex Program of Innovations in the Stevedoring Company of the Riga Port. Anatoly Gorohov (Latvia) Solution of the Basic Distribution and Supply Problems at the Level of Planning Logistic Processes. Leonid Khandurin (Latvia) Research’s Aspects of Logistics Service Development. Darius Bazaras, Ramūnas Palšaitis (Lithuania) Forecasting of the Freight Transportation by Lithuanian Railways. Daiva Griskeviciene, Algirdas Griskevicius, Albertas Simenas (Lithuania)

The Impact of Liberalisation of Transportation Market on the Activities of Freight Railway Enterprises in Lithuania. Raimundas Burkovskis, Ramunas Palsaitis (Lithuania) The Problem of Evaluating the Economic Efficiency of Managerial Decisions. Nataly Podolyakina (Latvia) Opportunity of Application of Artificial Intelligence Method in Economical Forecasting. Natalya Gode, Alexander Pchelkin (Latvia) Correlation of the Curve of Bond's Profitableness of Latvia, Lithuania and Estonia with the Basic Macroeconomic Indicators and their Convergence with the Leading Countries of the European Union. Vyacheslav Davidov (Latvia) Latvian Confidence Indicators as the Operative Indicators of Sector Development. Melihov Alexey, Svetlana Rusakova (Latvia) The Urgent Problems of the Estimation of Bank Risks under the Contemporary Conditions. Marina Kozhevnikova (Latvia)

Automated Management, Simulation and the Selection of Economically Effective Version in the Construction. L. Ustinovichyus, V. Popov, D. Migilinskas (Lithuania) Organizational Problems of Small Enterprises, Connected with the Problems of Growth. Roman Zaharov (Latvia) Estimation of Organizational Factors to the Cost of Business. Victor Siperkovsky (Latvia) Anticipating Macroeconomic Indicators as the Factor of the Determination of Investment Attractiveness in the Countries with the Transitional Economy. Vyacheslav Davidov, Rostislav Kopitov (Latvia) Method of Bringing the Flow of Money in the Changing Temporary Space during the Estimation of the Effectiveness of the Operating Enterprise. Rostislav Kopitov, Vladimir Labeyev (Latvia)

Decision Support of Web-Based System for Construction InnovatioE. K. Zavadskas, A. Kaklauskas, M. Viteikiene (Lithuania) Informational Modelling of the Regulations of the Transportation of Dangerous Freight for Database Management Systems. Nijole Batarlienė (Lithuania) The Refactoring Model for Dot_Net Framework. Sergey Orlov, Dmitry Morozov (Latvia) Management of Information or Informational Management? Vladimir Pyatkov, Eduard Fedchuk (Latvia) On the Formation of Sample during the Estimation of Training Process. Eduard Fedchuk, Alexander Pankov, Nataly Podolyakina (Latvia) Estimation and Perspectives of Information Systems (IS) of Lithuanian Railways. Aldona Jarasuniene (Lithuania) Quantity Management of Transport and Telecommunication Institute's Study Process Quality. Boriss Misnevs (Latvia)

On One Method of Determining the Quasi-Optimal Parameter of Regularization for Solving the Operator Equations of the First Kind with the Bounded Operator in the Hilbert Space. Maria Okruzhnova, Sharif Guseinov (Latvia) About One Effective Method for Solutions of First Kind Linear Operator Equations with Approximate Initial Data. Sharif Guseinov (Latvia) Control of the Holding Time of Tasks in the Single-Channel System of Queueing with the Delay of the Connection. Valery Nikolsky, Alexander Zinovyev (Latvia) Urban Traffic Intensity Simulation Based on Cellular Automaton Theory. Alexander Grakovski, Alexander Alexandrov, Alexey Rozhko (Latvia) Evaluation of Reliability Indices for Information Transport Networks. A. Latkov, V. Nikolsky, Y. Svirchenkov (Latvia) Method of Waiting Time On-Line Control in Computing Systems with Queues. V. Nikolsky, A. Latkov, Y. Svirchenkov (Latvia)

Transport and Telecommunication Vol.6, N 2, 2005

212

CONTENTS Session 4. Reliability of Aviation and Mechanical Systems The Influence of Corrosion on Reliability and Inspection Program for Fatigue – Prone Airframe Structures. M. Shujauddin Wahab, Yu. M. Paramonov ......................................................................................... 215

Stochastic Models of the Fatigue Crack Propagation Process. Konstantin N. Nechval......................................................................................................................... 225

Simulation of Dynamic Processes in Mechanical and Pneumatical System. Marijonas Bogdevicius ........................................................................................................................ 232

Simulation of the Influence of Mineral Materials’ Homogeneity on the Stability of Asphalt Concrete Mixes Grading. Henrikas Sivilevičius, Kęstutis Vislavičius .......................................................................................... 238

The Research on the Influence of the External Excitation Characteristics on the Dynamic “Man–Wheelchair–Vehicle” System. Mečislovas Mariūnas, Julius Griškevičius .......................................................................................... 245 Session 5. Efficiency of Electronics Systems and Devices Identification of Narrow-Band Discrete Systems. V. Yeremeyev, Т. Mamirov .................................................................................................................. 255

Short Wave Communication Lines Efficiency Increase in Civil Aviation. Alexander Mrochko, Yury Sikerzitski, Vladimir Shelkovnikov ............................................................ 260

The Analysis of the Receiving Antennae Effectiveness. Vladimir Shelkovnikov......................................................................................................................... 263 Session 6. Transport Possibility of Passenger Intermodality in Lithuania. Daiva Griskeviciene, Algirdas Griskevicius........................................................................................ 267

Development of Passenger Transportation by Lithuanian Sea Transport. J. Butkevičius, A. Vyskupaitis .............................................................................................................. 274

End-of-Life Vehicles and Transport Exploitation Materials Development Perspectives in Lithuania. A. Pikūnas, V. Valiūnas ....................................................................................................................... 280

The Impact of Anti-Lock Braking System on Braking Distance of the Vehicle. Valdas Valiūnas, Aurelijus Vestartas .................................................................................................. 283

Logistics Service Development and its Research Aspects. Darius Bazaras, Ramūnas Palšaitis .................................................................................................... 287

Forecasting of the Freight Transportation by Lithuanian Railways. Daiva Griskeviciene, Algirdas Griskevicius, Albertas Simenas .......................................................... 291 Session 7. Information Technology in Transportation and Education Informational Modelling of the Regulations of the Dangerous Freight Transportation for Database Management Systems. Nijole Batarliene ................................................................................................................................. 302

Estimation and Perspectives of Information Systems of Lithuanian Railway. Aldona Jarasuniene ............................................................................................................................. 307

Proceedings of International Conference RelStat’04 Part 2

213

Session 8. Computing Mathematics

Method of Waiting Time On-Line Control in Computing Systems with Queues, V. Nykolsky, A. Latkov, Y. Svirchenkov ................................................................................................312 Discussion Panel. Development of Transport Logistics in the Baltic States Interfaces between Logistics Centres and Lithuania Economical Development. Ramunas Palsaitis, Gintautas Labanauskas ........................................................................................319

The Development and Perspectives of Logistics Centres in Lithuania. Ieva Meidute.........................................................................................................................................322

Role and Place of Logistic Centre in Modern Conditions. Alexander Medvedev, Vladimir Zvonarev ............................................................................................328

Reliability of Aviation and Mechanical Systems


215

THE INFLUENCE OF CORROSION ON RELIABILITY AND INSPECTION PROGRAM FOR FATIGUE – PRONE AIRFRAME

STRUCTURES

M. Shujauddin Wahab, Yu. M. Paramonov

Riga Technical University, Aviation Institute Lomonosov Str.1, Riga, LV-1019, Latvia

Tel.: (+371)-7089950, Fax: (+371)-7089990, E-mail: [email protected] 1. INTRODUCTION

Fatigue crack growth analysis in the presence of corrosion is an important subject as shown in Figure 1 because it can degrade the structural integrity and damage tolerance of fatigue critical structural components in aging aircrafts [1]. Multiple site fatigue damage (MSD) in a longitudinal skin splice has been recognized as a major airworthiness problem. It had a very significant influence in Aloha B-737 incident in 1988.

Figure 1. Illustration of a corroded longitudinal fuselage splice from a retired 727:

(a) white corrosion product on faying surface, (b) corrosion pillowing detected by D Sight

For fleet management it is important to know the effects of corrosion in normal service on the durability and damage tolerance (DADT) characteristics of the fuselage. The DADT characteristic of any structure are defined by the crack initiation and growth patterns, the critical crack scenarios that could develop and the number of load cycles it takes for cracks to become detectable and then grow to a critical condition.

The crack development in a combined MSD and corrosion environment has characteristics that are quite different from and more stochastic than those related to a single crack situation.

The probabilistic analysis methodologies should be as simple as possible while maintaining reasonable accuracy for predicting the failure probability of fatigue critical components. The objective of this paper is to propose an accurate and cost-effective methodology for probabilistic analysis of lap splices that could be used in durability and damage tolerance assessments. 2. TEST PROGRAM

The MSD concept is illustrated by the generic lap splice version of the specimen clearly shown in Figure 2. A finite element model of the loop stress distribution in specimens is also shown. The concept is the use of bonded side straps to simulate the load transfer from cracked areas to surrounding structure that occurs on aircraft. The specimen shown is a 25.4 cm (10 in) wide version designed to be representative of the longitudinal fuselage splices in some narrow body transport aircraft. The splice in the generic specimen comprises two sheets of 1.0 mm (0.04 in) thick 2024-T3 Alclad held by three rows of 4 mm (5/32 in) diameter 20177-T4 rivets (MS20426AD5-5) without adhesive, paint or sealant. The rivet geometry results in a knife-edge countersink.


216

Figure 2. Illustration of MSD specimen (a) bonded doubler, (b) with a hoop stress distribution

at faying surface by finite element prediction

The average cycle number for the final failure for the corroded specimens is 207640 cycles. As shown in Figure 3, the corrosion damage in this MSD specimen (average thickness loss of between 5% and 6%) was compared with the damage in a section of splice from a Boeing 727 aircraft, shown in Figure 1, which was naturally corroded to a comparable level during 48,665 flights over 24 years. So 1 flight is approximately equivalent to 4.266 cycles.

Figure 3. MSD specimen corroded to 5% to 6% average thickness loss: (a) countersunk sheet with corrosion product still in place, (b) close-up near hole with corrosion product removed

The combination of corrosion and fatigue assumes that corrosion/fatigue interactions occur only

in the context of pre-existing corrosion and in a dry splice. This is a reasonable approximation for two reasons. First, teardown of aircraft splices and evidence indicates that substantial corrosion often exists without any associated fatigue cracking. Second, the highest in-service loads occur when any moisture in the splice is likely to have frozen.

There are altogether nine MSD specimens out of which five are non-corroded and four are relatively heavily corroded. They all are fatigue tested. These specimens are listed in Table 1 along with their respective fatigue life at visible crack detection, first link up and final failure. Table 1. Fatigue life of MSD Specimen

Fatigue Life (Cycles) Specimen # 1st observed 1st Linkup Final

failure Cgc-f38 387500 491711 501933 Cgc-f46 314000 398908 403718 Cgc-f51 304001 381378 392591 Cgc-f60 290000 368650 378754

Non-corroded

Cgc-f61 368500 473397 481353 Average Final Failure 431670

Cgc-cf34 160001 222450 Cgc-cf43 144000 189074 Cgc-cf45 104107 177129

Corroded to 5%-6%

level Cgc-cf58 142000 241909

Average Final Failure 207640


217

3. FAILURE CHARACTERISTICS

A significant difference was noticed in the behaviour of the MSD specimen with and without corrosion. The visible cracks were observed to start in different scenarios and there were distinct differences in load cycles to first observed cracks, which are shown in Table 1. The five non-corroded specimens showed visible cracks at between 2.9 and 3.88 * 105 cycles and failed at between 3.79 and 5.02 * 105 cycles. The statistical dispersion of visible crack detection and growth damage accumulation is large, which is a typical phenomenon of MSD specimens. The load cycles to visible crack detection of the non-corroded specimens represented 70% to 80% of their total fatigue life and similar behaviour was observed in the corroded specimen. The observed reduction due to corrosion in the mean cycles to visible crack detection was 59% for the specimens corroded to the 5% to 6% level.

In non-corroded specimens the crack grew with increasing load cycles from the central holes outward forming a pattern of multi-site damage as shown in Figure 4. Changes in gross failure modes were observed in the corroded specimens with the 5% to 6% level. The two dominant failure modes in corroded specimen are: (i) non-uniform MSD – one crack developed from only one site – at the rivet locations in the upper row and (ii) fatigue cracking at one or more sites in the inner (driven) sheet 5.08 to 7.62 mm (0.2 to 0.3 in) below the lower rivet row.

Figure 4. Typical MSD growth pattern in a non-corroded specimen

MSD tends to develop in clusters within the boundaries of a frame-bay. Similarly the linkup of MSD and the formation of a lead crack also tend to occur initially within a frame-bay for this curves that record the sum of all individual crack lengths at any given time. The crack length at a rivet hole is measured from the edge of the drilled hole. For cracks that developed away from the rivet rows, as in some corroded specimens the aggregate crack length is taken as the total tip to tip crack length. Where there were several such cracks in a specimen in an interacting MSD formation, overlapping cracks were regarded as linked cracks.

The test data for the crack growth history of the two specimen groups are shown in Figure 5 and 6. In the corroded specimens the overall crack growth rate was relatively stable during the whole growth period similar to the growth progression of a single crack. On the other hand in the non-corroded specimens, first linkup occurred at an aggregate crack length of about 50.8 mm (2 in). Subsequent crack growth was relatively fast and produced a pronounced knee in the growth curve.

0

25,4

50,8

76,2

101,6

127

152,4

177,8

1 1,25 1,5 1,75 2 2,25 2,5

Number of load cycles (x10^5)

Cra

ck le

ngth

(mm

)

Cgc-cf45

Cgc-cf58

Cgc-cf43

Cgc-cf34

Figure 5. Crack growth history data of corroded specimens


218

025.450.876.2

101.6127

152.4177.8

2.75 3 3.25 3.5 3.75 4 4.25 4.5 4.75 5 5.25

Number of load cycles (x10̂ 5)

Cra

ck le

ngth

(mm

)

Cgc-f38

Cgc-f46

Cgc-f51

Cgc-f60

Cgc-f61

Figure 6. Crack growth history data of non-corroded specimens

With above observation the total service life of a specimen is divided into two or three stages.

For non-corroded specimens, the total fatigue life, Nt, is divided into three parts: life to visible cracks or visible damage starting life, Ns, growth life before linkup, Ng1, and growth life after linkup, Ng2, that follow Nt = Ns + Ng1 + Ng2. For the corroded specimens to the 5% to 6% level, a single stage with growth life Ns, is used for the whole growth period because of their relatively stable growth behaviour and the total fatigue life is Nt = Ns + Ng. The visible damage starting life is the number of load cycles at which the first crack was observed and the total life of a specimen is when the final failure occurred. The growth life is the difference between the total life and the damage starting life Ng = Nt – Ns.

In a modern transport aircraft, the critical length of a single longitudinal crack in a fuselage skin is typically in excess of the frame bays about 10.16 cm (40 in). Crack growth rates are high when a lead crack reaches a length of several inches. The presence of MSD in adjacent frame-bays could reduce the critical length of the lead crack. Therefore first the splice is considered to have failed when the first linkup occurs at which the length of the aggregate lead crack a, reaches a specific value a1k. Second the splice is considered to have failed when the aggregate crack length reaches a critical value acr. The specific crack length for linkup and the critical crack length for final failure are taken from the mean values of the crack length obtained fro the test data corresponding to the linkup and failure life, respectively. For corroded specimen, only the final failure is considered. 4. DAMAGE STARTING LIFE AND STOCHASTIC GROWTH MODEL 4.1. Curve-fitting of Test Data

The test data are first imported into MS Excel and then fitted using a growth function, expressed as:

2*1CNCa = (1)

where a is the aggregate crack length, N is the number of load cycles, C1 and C2 are two constants taken from the Table 2. Table 2. Constants in fitted growth curves.

Growth stage 1 Growth stage 2 Specimen # C1 C2 C1 C2 Cgc-f38 1.39e-9 13.18 1.90e-40 57.69 Cgc-f46 2.16e-8 13.29 1.21e-35 58.84 Cgc-f51 5.59e-9 14.62 1.97e-30 51.30 Cgc-f60 2.48e-8 13.93 6.60e-22 37.86

Non-corroded

Cgc-f61 1.70e-10 14.92 4.52e-35 51.40 Cgc-cf34 0.0194 6.48 Cgc-cf43 0.0028 9.65 Cgc-cf45 0.2412 4.44

Corroded to 5% - 6%

level Cgc-cf58 0.0057 7.82


219

Two separate growth functions are used for the two growth stages of the non-corroded specimens. The junction of the two growth curves is selected to occur where the crack length is 2 in (50.8 mm). The life corresponding to this specific crack length is called the growth rate transition life. The growth rate transition life is close to the linkup life but the two are not the same. A single function is fitted for the whole growth period of the specimens corroded to the 5% to 6% level. The fitted curves are shown in Figures 5 – 6 and the constants determined for the growth functions are listed in Table 2.

The final critical size of the crack (ac) is taken to be 2 inches (50.8 mm) for both the corroded and non-corroded specimens. In investigating damage growth behaviour, an initial crack is assumed to exist in each specimen. In this work, the length of the initial visible detectable crack (ad) is taken as 0.08 in (2.032 mm) for all specimens. This is approximately the average crack length for all specimens at the first observation.

4.2. Determination of Fatigue Crack Growth Function Parameters

Following Yang’s paper it is assumed that fatigue crack growth of some items of airframe is

defined by formula [2, 3]:

( ) ( ) ( )( )( ) μμμ1

1 Qtoaoata −= (2)

where

12 −= mμ . (3)

In this paper we consider the case when m ≠ 2. The parameter μ – depends on the material characteristics; a(0) – equivalent beginning size of a

crack. Processing of data for crack growth during fatigue experiments using least square method, we

can get estimates of this equation parameters. Results of processing four fatigue crack growth data for corroded specimens at 5%-6% level are

given in Table 3. Table 3. Fatigue crack growth parameters for corroded specimens at 5%-6% level

Serial No. Specimen # μ bo = ln Q a(0)

1. Cgc-cf34 -0.15424 -9.75393 2.37E-19 2. Cgc-cf43 -0.10353 -9.52048 1.48E-27 3. Cgc-cf45 -0.22511 -9.61464 4.51E-13 4. Cgc-cf58 -0.12758 -9.70537 1.63E-18

Average -0.15262 -9.6486 1.13E-13 Standard Deviation 0.052581 0.103096 2.26E-13

Results of processing of five fatigue crack growth data for non-corroded specimens are given in

Table 4. Table 4. Fatigue crack growth parameters for non-corroded specimens

Serial No. Specimen # μ bo = ln Q a(0)

1. Cgc-f38 0.432273 -11.2323 0.079004 2. Cgc-f46 0.44934 -11.0738 0.091935 3. Cgc-f51 0.334914 -10.6355 0.02707 4. Cgc-f60 0.249426 -10.5026 0.014186 5. Cgc-f61 0.322694 -10.7252 0.018577

Average 0.35773 -10.8339 0.046155 Standard Deviation 0.082805 0.307091 0.036475


220

4.3. Simulation of a Process of Fatigue Crack Inspection

It is assumed that some inspection technology is characterized by two values: ad and wi; ad - the minimum size of a detectable crack and w – is interpreted as probability that the earlier scheduled inspection will be made with required accuracy. Service time when crack becomes detectable td and service time to fatigue failure tf are defined below:

QC

t dd =

QC

t ff = (4)

We consider, that td and tf are functions of random variable Q. Cd – constant for both non-corroded and corroded specimens with different a(0).

( )

( )( )μ

μ

μ oaa

oa

C dd

⎟⎟⎠

⎞⎜⎜⎝

⎛−

=

1 (5)

Where ad is the initial detectable size of the fatigue crack. Cf – constant for the case when μ – negative. It takes place for the corroded specimens

( )( ) ( )( )⎥⎥⎦

⎤

⎢⎢⎣

⎡ −∗=

γπσ γγ

oaKC c

f12

max (6)

Cf – is constant for the case when μ – positive. It takes place for the non-corroded specimens.

( )

( )μ

μ

μ

πσ

oa

Koa

C

c

f

⎟⎟⎟⎟⎟

⎠

⎞

⎜⎜⎜⎜⎜

⎝

⎛

−

=2

max

21

(7)

Bar chart of crack undetectable and crack detectable time periods (CUCDTP) in both cases are shown in Figure 7 and 8.

0 200000 400000 600000

13579

1113151719

Aircrafts

T

0 200000 400000 600000

13579

1113151719

Aircrafts

T

Figure 7. Bar chart of CUCDTP for the corroded specimens at 5% and 6% level

Figure 8. Bar chart of CUCDTP for the non-corroded specimens


221

4.4. Estimation of Fatigue Failure Probability

If we use Monte Carlo (MC) method then the failure probability in the interval (td, tf)j with rj inspections on the j-th airplane is defined by formula:

( ) jrjf wp −=

∧

11 (8)

w – is a probability that planned inspection will be made with required accuracy. Then for N airplanes (or for N Monte Carlo trials) mean failure probability (Pf) will equal to:

∑=

∧

=N

jjff P

Np

11

1 . (9)

For the case when w =1 it can be shown that [4, 5]:

∑=

•=n

iif pp

1

(10)

Where

⎪⎪⎩

⎪⎪⎨

⎧

>

≤

=

−

−∗

i

f

i

di

i

f

i

d

i

tC

tC

if

tC

tC

ifp

1

1

,

,0

π

(11)

=−⎟⎟⎠

⎞⎜⎜⎝

⎛=

− i

fQ

i

dQi t

CF

tC

F1

π (12)

( ) ( )⎟⎟⎠

⎞⎜⎜⎝

⎛ −−⎟⎟

⎠

⎞⎜⎜⎝

⎛ −= −

1

0

1

01 lnlnθ

θφ

θθ

φπ ifidi

tCtC (13)

4.5. The Choice of First Interval t1

The choice of first interval t1 can be made on the condition of limitation of probability of failure in interval [0,t1] by small value ε :

( ) 001.0lnln: 11 ==< εtTPt f . (14)

Usually it is assumed that lnTf has normal distribution N(θ0, θ12) where θ0 = θ0 (lnTf), θ1 = θ1

(lnTf) are mean and standard deviation of lnTf.

QC

T ff = . (15)

Then

( ) ( )( ) ⎥

⎥⎦

⎤

⎢⎢⎣

⎡ −Φ=<

f

ff T

TttTP

lnlnln

lnln1

011 θ

θ (16)


222

( ) ( ) ( )ff TTt lnln*ln 011

1 θθε +Φ= − . (17)

There is a relationship.

QCT ff lnlnln −= . (18)

Then

( ) ( ) ( )ff TQCt ln*lnlnln 11

01 θεθ −Φ+−= (19)

If all the other Δi are equal, then interval between inspections is as follow as:

( )n

tTSL 1−=Δ (20)

where tSL – specified life of an aircraft n – number of inspections (including first interval).

Examples of calculation of t1 for the corroded specimens are given in the Table 5. Table 5. First time interval t1

ε Φ-1(ε) LnCf lnt1 t1=exp(lnt1) 0,001 -3,09024472 2,4734724 11,65854 115674,9109

Examples of calculation of t1 for the non-corroded specimens are given in the Table 6. Table 6. First time interval t1

ε Φ-1(ε) lnCf lnt1 t1=exp(lnt1)

0,001 -3,09024472 2,0431005 12,41344 246085,9357 All the other moments of inspection are defined by the following formula:

( )11 −Δ+= itti (21)

where i = (1,2,3,….,n). Relevant curves Pf = Pf (Δ) are shown in Figure 9 and 10.

Pf = Pf (Δ ), a_d=2,032mm

0,00,10,20,30,40,50,60,70,80,91,0

0 100000 200000 300000 400000 Δ

Pf

Pf = Pf (Δ ), a_d=2,032mm

0,00,10,20,30,40,50,60,70,80,91,0

0 100000 200000 300000 400000Δ

Pf

Figure 9. Failure probability for the corroded specimen with specified life = 450000 cycles

Figure 10. Failure probability for the non-corroded specimen with specified life = 450000 cycles


223

At a first glance it is surprising that for the corroded specimens the probability of failure does not grow higher than 0.48. The reason is that at the first inspection (t1 = 115674) we discover approximately 52% of cracks (see Fig 7 and 9). But for the non-corroded specimens (at t1 = 246085) we do not see any fatigue crack (see Fig 8 and 10). This means that a more sophisticated strategy of t1 choice should be developed. But this is a subject of another paper.

4.6. Choice of the Number of Inspections

We can choose n (number of inspections) for allowable failure probability (Pf ≈ 0.017). The value 0.017 should be considered just as an example (Really it is defined by the limited time of Monte Carlo analysis). Monte Carlo method when t1>d. Detectable size of the crack is equal to 2.032 mm and final critical size of the crack is equal to 50.8 mm.

The required number of inspections (n) for different specified lives (SL), which are expressed in

cycles, are shown in Table 7 and 8 for corroded and non-corroded specimens respectively.

(To remind that the first interval t1(ε) = 115674,9109 cycles). Table 7. Required number of inspections for corroded specimens

w =1 w =0.9 Specified Life n n

400000 4 8 450000 5 9 500000 6 11

(To remind that the first interval t1 (ε) = 246085,9352 cycles).

Table 8. Required number of inspections for non-corroded specimens

w=1 w=0,9 Specified Life n n

400000 3 4 450000 4 6 500000 5 7

w – is a probability that planned inspection will be made with required accuracy. 5. CONCLUSIONS

For corroded specimens the required number of inspection (n) (for reliability R = 1 – 0.017) increases. When TSL=400000 cycles and b=0, it is less significant for the case when w=1 where the required number of inspections increases from 3 to 4. But it is very significant for the case when w=0.9 where the number of inspections increases from 4 to 8, that is two times higher. This shows that with the influence of corrosion the number inspections required doubles in the case of corroded specimens as compared to the non –corroded specimens.


224

References [1] Xiong Y., Eastaugh G., Shi G. Probabilistic failure analysis of fuselage splice joints with multiple site

fatigue damage and corrosion. In: Proceedings of the Twentieth ICAF (International Committee on Aeronautical Fatigue) Symposium, Bellevue, Washington, USA, 14 – 16 July 1999, Structural Integrity for the next Millennium / Edited by Bader R. M. and Rudd J. L., 2 Volumes. Washington, USA, 1999. 1232 p.

[2] Парамонов Ю. М., Кузнецов В. П. Живучесть авиационных конструкций. Оценка эффективности эксплуатации по состоянию, МУ. По выполнению самостоятельной работы. 1990. 24 c.

[3] Yang J.N. Statistical Crack Growth in Durability and Damage Tolerant Analysis. In: 22nd Structures, Structural Dynamics and Materials Conference. 1980, pp. 38-49.

[4] Paramonov Yu. M., Bharati R. Mathematical Models of the Process of Airframe Fatigue Problem Solution for the Purpose of Automated System Development, Transactions of RAU, Mechanical Department, 1997, pp. 123-126.

[5] Wahab M. Shujauddin, Paramonov Yu. M. Influence of Corrosion on the Required Number of an Airframe Inspection. Transport and Telecommunication Institute Volume 5, No1. In: Proceedings of the International Conference “Reliability and Statistics in Transportation and Communication” (RelStat’03) 16-17 October 2003, Vol.1, 2004, pp. 180-190.


225

STOCHASTIC MODELS OF THE FATIGUE CRACK PROPAGATION PROCESS

Konstantin N. Nechval

Transport and Telecommunication Institute

Computer Science Department Lomonosov Street 1, LV-1019 Riga, Latvia

Email: [email protected] 1. INTRODUCTION

Based on engineering and macroscopic viewpoints, the mechanical properties of metallic materials are often considered homogeneous. However, a considerable amount of scatter has been observed in fatigue data even under the same loading condition. It may be attributed to the inhomogeneous material properties. As a result, probabilistic approaches for the fatigue crack growth have received great attention in recent years. Along with the development of fracture mechanics for the past three decades and the need of reliability or risk assessment for some important structures or components such as nuclear power plant and aircraft structures, the so-called ‘probabilistic fracture mechanics’ has thus arisen [1]. One of the important issues in the probabilistic fracture mechanics analysis lies in the probabilistic modelling of fatigue crack growth phenomenon. Many probabilistic models have been proposed to capture the scatter of the fatigue crack growth data. Some of the models are purely based on direct curve fitting of the random crack growth data, including their mean value and standard deviation [2]. Other researchers, however, have criticized these models, that, less crack growth mechanisms have been included in them. To overcome this difficulty, many probabilistic models adopted the crack growth equations proposed by fatigue experimentalists, and randomised the equations by including random factors into them [3, 4, 5, 6, 7, 8, 9 and 10]. The random factor may be a random variable, a random process of time, or a random process of space. It then creates a random differential equation. The solution of the differential equation reveals the probabilistic nature as well as the scatter phenomenon of the fatigue crack growth.

To justify the applicability of the probabilistic models mentioned above, fatigue crack growth data are needed. However, it is rather time-consuming to carry out experiments to obtain a set of statistical meaningful fatigue crack growth data. To the writers' knowledge, there are only a few data sets available so far for researchers to verify their probabilistic models. Among them, the most famous data set perhaps is the one produced by Virkler et al. more than twenty years ago [11]. Two more frequently used data sets include one reported by Ghonem and Dore [12], and the other released by the Flight Dynamics Laboratory of the US Air Force [13]. Itagaki and his associates have also produced some statistically meaningful fatigue crack growth data, but have not been mentioned very often [14]. In fact, many probabilistic fatigue crack growth models are either lack of experimental verification or just verified by only one of the above data sets. It is suspected that a model may explain a data set well but fail to explain another data set. The universal applicability of many probabilistic models still needs to be checked carefully by other available data sets.

While various stochastic fatigue crack growth models have been proposed, there are limited statistically meaningful data sets that can be used to verify these models' appropriateness or accuracy. The objective of the present paper is to use the available experimental data to verify a stochastic log-linear fatigue crack growth model proposed in this paper. 2. STOCHASTIC MODELS

Several probabilistic or stochastic models have been employed to fit the data from various fatigue crack growth experiments. Among them, the Bogdanoff and Kozin's Markov chain model, Yang's second-order approximation model, the modified second-order polynomial model, and a stochastic log-linear fatigue crack growth model all produced satisfactory results. These models are presented briefly below.


226

2.1. Markov Chain Model

In the Markov chain model proposed by Bogdanoff and Kozin, a duty cycle (DC) is defined as a repetitive period of operation in the life of a component during which damage can accumulate. It is assumed that the increment of damage at the end of a DC depends in a probabilistic manner only on the amount of damage present at the start of the DC and on the DC itself. It is independent of how damage was accumulated up to the start of that DC. If the degrees of damage are characterized by discrete states, the probabilistic structure of the damage at the end of each DC can be described by a state vector pk consisting of b states, i.e.

pk={pk(1), pk(2), …, pk(b)}. (1)

It can be calculated easily based on the Markov assumption through the following formula

pk=p0Pk=pk−1P, (2)

in which p0 is the initial probability distribution, pk−1 is the probability distribution at the end of the previous DC, and P is a transition matrix consisting of

.

1 0 0 0 0 0 0 0

0 0 0

0 0 0

11

22

11

⎥⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢⎢

⎣

⎡

=

−−

L

L

MMOMMM

L

L

ss qp

qpqp

P (3)

where pj denotes the probability of stay at the same state, and qj=1−pj denotes the probability of transit from one state to the next after each DC. It is noted that the transition matrix has s−1 state-dependent transition states; one absorbing state, and only unit-jumps are permitted. The unit-jump restriction, however, can be lifted to make the transition matrix more complicated. Moreover, if P is set to be time-dependent, then the damage model becomes a non-stationary one.

In the fatigue crack growth problem, the above damage should be interpreted as the crack size, and a DC consists of several loading cycles. Based on the Markov chain model, both the cumulative distribution function of time to reach a certain state (including failure state) and the cumulative distribution function of crack size at a certain DC can be obtained easily. The reliability function and failure rate can also be calculated accordingly. The appropriate values of s and pj, however, are to be obtained from the experimental data. If a stationary model is not enough to characterize the crack growth process, non-stationary models can be employed to describe this evolutional process. The detailed derivation of the required formulas to complete the modelling will not be described herein for the sake of simplicity. Interested readers are encouraged to refer to Bogdanoff and Kozin's book [2]. 2.2. Yang's Power Law Model

The above Markov chain model has been criticized as lack of physical meaning and is more of a statistical model. To be compatible with the physically meaningful fatigue crack growth process, the following Paris law, used by many fatigue experimentalists, is frequently considered

,)(dd mKCNa

Δ= (4)

in which a is the crack length, N is the number of load cycles, C and m are material constants, and ΔK is the stress intensity factor range that is related to the applied load, crack length and material geometry. The stochastic modelling then considers at least one of the above parameters as random variables or simply adds a random factor into the above Paris law to make it a stochastic differential equation. The probability distribution of random crack size or probability distribution of random cycles to reach a given crack size can therefore be determined. However, owing to the difficulty in the calculation of ΔK in real situations as well as the difficulty in obtaining a closed-form solution of the


227

differential equation, the Paris law is sometimes modified or simplified to a certain degree. For example, Yang and Manning have suggested the following simpler form of the above equation after investigations of crack propagation in fastener holes of aircrafts under spectrum loading [15]

,)]([)(d

)(d btaQtXtta

= (5)

in which X(t) is a random factor, Q and b are constants to be evaluated from the crack growth observation. The independent variable t can be interpreted as either stress cycles, flight hours, or flights depending on the applications.

According to Yang and Manning, if the above random factor X(t) is modelled as a stationary lognormal random process having a unit mean-value and an auto-covariance function of

),exp(])(),(Cov[ 122

21 tttXtX X −−= ζσ (6)

the probability structure of the stochastic fatigue crack growth process can be obtained analytically. In particular, the probability of crack exceed, )(

)(etaP , and the probability distribution of random time to

reach a given crack size, FT(a), can be found without difficulty. They have the same form as

, )(

/)(lnln)()( )()()( ⎟⎟

⎠

⎞⎜⎜⎝

⎛ −==

tattΦtFaP

XaT

eta σ

λ (7)

in which Φ is the cumulative distribution function of the standard normal random variable, )(at indicates the median service life for the crack to reach a, σX(t) is the standard deviation of the

logarithm of the integrated X(t), and λ is a latent time parameter related to σX and ζ in Eq. (6). The detailed derivation of the above equations can be found in Yang and Manning's paper [15].

The greatest advantage of Yang's model lies in its flexibility in the choice of ζ that, in turn, is related to (the inverse of) the correlation time of the random factor X(t). If the correlation time ζ−1 approaches to zero, indicating that X(t) is a lognormal white noise random process, Eq. (7) becomes

, 2

exp)()()(2

)()()( ⎟

⎟⎠

⎞⎜⎜⎝

⎛⎟⎟⎠

⎞⎜⎜⎝

⎛−−== X

aTeta attUtFaP σ

(8)

in which σX is the standard deviation of lnX, and U is a unit step function. It indicates that there is a sudden jump for the associated probability at ).2/exp()( 2

Xatt σ−= There is no statistical dispersion for the crack growth accumulation in this case. Hence, the model can be considered as the most non-conservative stochastic modelling. For the other extreme case, if the correlation time ζ−1 approaches to infinite, indicating that X(t) degenerates to a lognormal random variable X, Eq. (7) then becomes

, )(lnln)()( )()()( ⎟⎟

⎠

⎞⎜⎜⎝

⎛ −==

XaT

eta

attΦtFaPσ

(9)

which is identical to the result derived previously by Yang and his associates in earlier years [16] and it indicates the most conservative case in the stochastic modelling. By the appropriate choice of a correlation time within the above two extreme cases, Yang's model is thus very versatile as the Markov chain model is. 2.3. Polynomial Model

If Paris law can be simplified to be Yang's power law in the stochastic modelling of fatigue crack growth, it can also be simplified to other forms. This is needed if Yang's model is found to be inadequate in describing the probabilistic structure of the growth process. However, a complicated fatigue crack growth law may result in numerical complexity, especially when a random factor is


228

added to it. To obtain a compromise between the crack growth mechanism and the numerical simplicity, polynomial models could be considered in the stochastic modelling. In particular, the following second-order polynomial fatigue crack growth model is studied

],)]([)()[(d

)(d 2tartqaptXtta

++= (10)

in which p, q, r are polynomial constants, and X(t) is the same stationary lognormal random process as the one used in Yang's model. The polynomial constants are, of course, related to the characteristics of the studied material as well as the environmental loading. Following the derivation of Yang's model, many formulas can be obtained in closed-forms. For example, the median service time to reach any specified crack size a from initial crack size a0 can be obtained as

,2

)2(tan2)( 1

⎥⎥⎦

⎤

⎢⎢⎣

⎡

+++−

= −

rAaGAqGqAra

Gat (11)

in which A=2ra0+q and G=4pr−q2. The probability of crack exceed and probability distribution of random time to reach a given crack size can be obtained from

,)(

)](ln[Φ))((1)()( )(

)()()()( ⎟⎟

⎠

⎞⎜⎜⎝

⎛ −=−==

tat

atFtFaPX

tXtWaT

eta σ

μ (12)

in which W(t) is the integrated X(t), μX(t) is the mean value of the logarithm of the integrated X(t), and σX(t) is the standard deviation of the logarithm of the integrated X(t). The latter two quantities can be obtained based on Eq. (6) and the assumption for X(t) made before. Detailed derivations and expressions for these probability distributions can be found in [17].

Similar to Yang's power law model, there are two extreme cases for the polynomial model. For the simplest extreme, if X(t) is considered a lognormal random variable, it can be shown that

,2

)2(tan2ln

Φ))((1)()(

1

)()()()(

⎟⎟⎟⎟⎟⎟

⎠

⎞

⎜⎜⎜⎜⎜⎜

⎝

⎛

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

⎥⎥⎦

⎤

⎢⎢⎣

⎡

+++−

=−==

−

XtWaT

eta

rAaGAqGqAra

GtatFtFaP

σ (13)

The γ percentile of the crack size at a service time t can also be derived as

.

2tan2

2tan)()(

)(

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛⎟⎟⎠

⎞⎜⎜⎝

⎛−

⎟⎟⎠

⎞⎜⎜⎝

⎛++−

=

txGAGr

txGGAqGqAta

γ

γ

γ (14)

However, for the other extreme that X(t) is a lognormal white noise process, the probability distributions have to be obtained numerically by Monte Carlo method.

2.4. Log-linear Fatigue Crack Growth Model

Fracture mechanics theory is used to determine the length of a propagating crack under random stress. This theory can predict crack size as a function of time. For the purposes of this study, it is assumed that a crack grows according to the Paris and Erdogan [18] equation:


229

,)]([d

)(d BxaQxxa

= (15)

where a(x) is the crack size of a fastener hole at x flight-hours, and Q and B are material parameters. This model has been used successfully to describe the observed propagation of a dominant crack in many experiments and the values Q & B have been established for a wide range of materials. Integrating eqn (15) from the initial crack length a(τ0) at the time of crack initiation x=τ0 up to the current crack length a(τ) at time x=τ, one obtains the relation between the crack size, a(τ), at any service time τ and the initial crack size, a(τ0), as follows

[ ] .][]1[)]([1

)()( )1/(1 0

10

0−− −−−

= BB QBa

aaτττ

ττ (16)

For the special case in which B=1, it can easily be shown that

]).[exp()()( 00 τττ −=τ Qaa (17)

Available in-service inspection data for various types of aircraft indicate that the Weibull or lognormal distribution provides a reasonable fit for B and Q in both cases. In this paper, for the sake of simplicity but without loss of generality, only a special case in which B=1 is considered. This suggests, by taking logarithm, the following model

ln[a(τ)] = ln[a(τ0)] + Q[τ-τ0], (18)

where Q follows a Weibull distribution, the cumulative distribution function of which is given by

⎩⎨⎧ ≥−−

=otherwise, 0,

0, ],)/(exp[1)(

qqqF

δ

θσ

(19)

with unknown parametric vector θ=(σ,δ). Let a• be the operational limit crack size for the degradation path, which is permitted for the initial crack to grow and reach a• at time x=T•, then we can write

ln(a•)=ln[a(τ0)]+Q[T•−τ0], (20)

where

T•−τ0 = [ln(a•)−ln[a(τ0)]/Q =Q

aa )](/ln[ 0τ•

(21)

represents a time permitted for the initial crack to grow and reach the operational limit crack size a•. The distribution function of T• is given by

}Pr{)( 00 ττθ −≤−= ••• tTtG⎭⎬⎫

⎩⎨⎧

−≥=

⎭⎬⎫

⎩⎨⎧

−≤= •

••

•

0

00

0 )](/ln[Pr)](/ln[Prτ

τττt

aaQtQ

aa

0. ,][)](/ln[exp)](/ln[1 0

0

0

0

0 >−⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛−

−=⎟⎟⎠

⎞⎜⎜⎝

⎛−

−= ••

•

•

•

τtt

aat

aaFδ

θ τστ

ττ

(22)

Thus, a random variable Z(0)≡Q=[ln(a•/a(τ0))]/[T•−τ0] follows the Weibull distribution with the cumulative distribution function


230

⎩⎨⎧ >−−

=otherwise. 0,

0,z(0) ],)/)0((exp[1))0((

δ

θσz

zF (23)

Similarly, if Q follows a lognormal distribution (μ,σ2), the distribution function of T• is given by

}Pr{)( 00 ττθ −≤−= ••• tTtG⎭⎬⎫

⎩⎨⎧

−≥=

⎭⎬⎫

⎩⎨⎧

−≤= •

••

•

0

00


τττt

aaQtQ

aa

0, ,

)](/ln[ln1 0

0

0

>−

⎟⎟⎟⎟⎟

⎠

⎞

⎜⎜⎜⎜⎜

⎝

⎛−⎟⎟

⎠

⎞⎜⎜⎝

⎛−

Φ−= ••

•

τtt

aa

σ

μτ

τ

(24)

where Φ(⋅) is the standard normal distribution function. Thus, a random variable Z(0)≡Q =[ln(a•/a(τ0))]/[T•−τ0] follows the lognormal distribution with the probability density function

,2

))]0((ln[exp)0(2

1))0(( 2

2

⎟⎟⎠

⎞⎜⎜⎝

⎛ −−=

σμ

σπθ

zz

zf z(0)>0, −∞<μ<∞, σ>0, (25)

where θ=(μ,σ2). Let Q ~ N(μ,σ2) with σ«μ so that Pr{Q≤0} is negligible. Then the distribution function of T• is

given by

}Pr{)( 00 ττθ −≤−= ••• tTtG⎭⎬⎫

⎩⎨⎧

−≥=

⎭⎬⎫

⎩⎨⎧

−≤= •

••

•

0

00


τττt

aaQtQ

aa

0. ,

)](/ln[

1 00

0

>−

⎟⎟⎟⎟⎟

⎠

⎞

⎜⎜⎜⎜⎜

⎝

⎛−

−Φ−= •

•

•

τttaa

σ

μτ

τ

(26)

Thus, a random variable Z(0)≡Q =[ln(a•/a(τ0))]/[T•−τ0] follows the normal distribution with the probability density function

,2

))0((exp21))0(( 2

2

⎟⎟⎠

⎞⎜⎜⎝

⎛ −−=

σμ

σπθ

zzf z(0)>0. (27)

It is assumed that the above takes place for all Z(j) ≡Q =[ln(a(τj+1)/a(τj))]/[ τj+1 −τj], where τj+1 >τj, a(τj+1) ≤a•. 3. CONCLUSIONS

After extensive study of various sets of fatigue crack growth data, it is concluded that Markov chain model, Yang’s power law model, polynomial model and log-linear fatigue crack growth model can all be used to describe the stochastic growth process. Each of the models may be the most appropriate one to depict a particular set of fatigue growth data but not necessarily the others. All models can be improved to depict very accurately the growth data but, of course, it has to be at the cost of increasing computational complexity. In the present study, fortunately, the simplest lognormal


231

random variable used in either Yang’s model or polynomial model is sufficient to describe the studied fatigue crack growth data. The Markov chain model has been criticized to be unable to depict the fatigue crack growth mechanism. Yang’s model and the polynomial model are considered more appropriate than the Markov chain model by some researchers through the introduction of a differential equation which indicates that fatigue crack growth rate is a function of crack size and other parameters. The parameters, however, can only be determined through the observation and measurement of many crack growth samples. If fatigue crack growth samples are observed and measured, descriptive statistics can then be applied directly to the data to find the distributions of the desired random quantities. Thus, these models still lack prediction algorithms. Moreover, they are mathematically too complicated for fatigue researchers as well as design engineers. The log-linear fatigue crack growth model is attractively simple and easy to apply in practice. A large gap still needs to be bridged between the fatigue experimentalists and researchers who use probabilistic methods to study the fatigue crack growth problems. ACKNOWLEDGMENTS

This work was supported by the Latvian Council of Science under Grant No. 99-79d. References [1] Proven J.W. Probabilistic Fracture Mechanics and Reliability. Martinus Nijhoff, Dordrecht, The

Netherlands, 1987. [2] Bogdanoff J.L., Kozin F. Probabilistic Models of Cumulative Damage. New York: Wiley, 1985. [3] Lin Y.K., Yang J.N. On Statistical Moments of Fatigue Crack Propagation, Engng Fract Mech, 18, 1983,

pp. 243-262. [4] Yang J.N., Manning S.D. Stochastic Crack Growth Analysis Methodologies for Metallic Structures, Engng

Fract Mech, 37, 1990, pp. 1105-1124. [5] Zhu W.Q., Lin Y.K., Lei Y. On Fatigue Crack Growth under Random Loading, Engng Fract Mech, 43,

1992, pp. 1-12. [6] Sobczyk K., Spencer B.F. Random Fatigue: from Data to Theory. Boston: Academic Press, 1992. [7] Ishikawa H., Tsurui A., Utsumi A., Tanaka H. Effect of Stress Ratio on Crack Propagation Life

Distribution under Random Loading, Probab Engng Mech, 8, 1993, pp. 35-41. [8] Wu W.F., Shin C.S., Shen J.J. Probabilistic Analysis of Fatigue Crack Propagation under Random

Loading, ASME J Pressure Vessel Technol, 116, 1994, pp. 216-225. [9] Tanaka H., Toyoda-Makino M. Cost-Based Optimal Relation between Inspection Time and Assessment

Time for Random Fatigue Crack Growth, Probab Engng Mech, 13, 1998, pp. 69-76. [10] Kirkner D.J., Sobczyk K., Spencer B.F. On The Relation of the Cumulative Jump Model for Random

Fatigue to Empirical Data, Probab Engng Mech, 14, 1999, pp. 257-267. [11] Virkler D.A., Hillberry B.M., Goel P.K. The Statistic Nature of Fatigue Crack Propagation, ASME J Engng

Mater Technol, 101, 1979, pp. 148-153. [12] Ghonem H., Dore S. Experimental Study of the Constant Probability Crack Growth Curves under Constant

Amplitude Loading, Engng Fract Mech, 27, 1987, pp. 1-25. [13] Yang J.N., His W.H., Manning S.D. Stochastic Crack Propagation with Applications to Durability and

Damage Tolerance Analyses: Technical Report. Flight Dynamics Laboratory, Wright-Patterson Air Force Base, AFWAL-TR-85-3062, 1985.

[14] Itagaki H., Ishizuka T., Huang P.Y. Experimental Estimation of the Probability Distribution of Fatigue Crack Growth Lives, Probab Engng Mech, 8, 1993, pp. 25-34.

[15] Yang J.N., Manning S.D. A Simple Second Order Approximation for Stochastic Crack Growth Analysis, Engng Fract Mech, 53, 1996, pp. 677-686.

[16] Yang J.N., Manning S.D., Rudd J.L., His W.H. Stochastic Crack Propagation in Fastener Holes, AIAA J Aircraft, 22, 1985, pp. 810-817.

[17] Wu W.F., Ni C.C., Liou H.Y. Random Outcome and Stochastic Analysis of Some Fatigue Crack Growth Data, Chin J Mech, 17, 2001, pp. 61-68.

[18] Paris P., Erdogan F. A Critical Analysis of Crack Propagation Laws, Trans. ASME, 85, 1963, pp. 528-534.


232

SIMULATION OF DYNAMIC PROCESSES IN MECHANICAL AND PNEUMATICAL SYSTEM

Marijonas Bogdevicius

Department of Transport Technological Equipment, Faculty of Transport Engineering

Vilnius Gediminas Technical University Plytinės g. 27, LT-10105 Vilnius-16. Lithuania

Tel. (+370 5) 274 47 84, e-mail: [email protected], www.vgtu.lt/fakultetai/transport/technolog 1. INTRODUCTION

Pneumatic drive together with mechanical, electrical, and hydraulic drives have been widely used in mechanical engineering, transport, power engineering etc. Pneumatic drives have one essential disadvantage: the influence of transient processes on its main work. Density of gas in pneumatic drive has the greatest influence on transient processes. The main parameters in pneumatic drives are selected according to the calculation results of transient processes. Therefore, there is a necessity to carry out calculation of the transient processes in pneumatic drive very precisely. Most often pneumatic drive are investigated as systems with concentrated parameters. Taking this assumption into consideration, it is not possible to evaluate pressure wave propagation in pneumatic drive. Therefore, it is not possible to study the impact of shock wave and hydraulic impact on the pneumatic drive elements connected with simple and complicated pneumatic signal transmission lines.

The accuracy of pneumatic mechanisms depends not only on gas parameters and management factors but also on mechanical factors. The most important factors influencing the accuracy of pneumatic drive are frictional and inertial forces. Therefore, when studying transient processes in pneumatic drive, the impact of these factors shall be evaluated accurately.

In this article the dynamic processes in the drive together with the asynchronous engine, coupling with gas, and mechanical drive are considered. The distinguishing property of this coupling is that semi-couplings interact with each other through gas. The coupling of this type consists of separate segments, where additional masses are used. Every segment consists of three pipelines.

Many authors investigated the pneumatic system as the system with lumped values and thus did not take into consideration wave processes going on in pneumatic lines [1]. The present work aims to show wave processes going on in the coupling system as well investigated dynamic processes in the drive as a general system. 2. DYNAMIC MODEL OF DRIVE

Drive consists of the asynchronous engine, the coupling with gas and mechanical drive (Fig. 1a). The coupling of this type consists of separate segments, where additional masses are input (Fig. 1, b).

a) b)

Figure 1. A circuit of a mechanical driver: a − calculated circuit of mechanical driver; b − calculated circuit of segment


233

The asynchronous engine dynamic model is presented [1, 2]:

{ } ( ){ }eB ϕψψ ,=& , ( ) ( )pMMI eee ,11 ϕψϕ −=&& (1)

where: { }ψ − bound flow vector; ( ){ }eB ϕψ , − vector of parameter of the asynchronous engine; eI − rotor inertia moment; eϕ − rotor turning angle; eM − engine turning moment; ( )pM ,11 ϕ − engine resistance moment; 1ϕ − turning angle of semi-coupling one; p − gas pressure in the segments.

The system of equations of drive is the following

( ) ( ) 11,121,111 Σ−−−−−= MhkI eee ϕϕϕϕϕ &&&& ;

( ) ( )323,2323,2222 ϕϕϕϕϕ &&&& −−−−= Σ hkMI ;

( ) ( ) ( )tMhkI r−−−−−= 233,2233,233 ϕϕϕϕϕ &&&& ;

( ) ( )[ ]+−+−+Δ−= 1,0,11,01,1,100 qqhqqkrI iiiiiii &&&&ϕ

( ) ( )[ ]2,0,2,022,2,2 qqhqqkr iiiii && −++−Δ+ ;

( ) ( ) 2,0,3,3,3,3,3,3,3,3,3,3,3,3 iiiiiiiiiiiii qrmqhqkpSqm ϕ&&&& −−−+Δ−=

( )nsegi ,...,1= (2)

where: 1I , 2I − semi-coupling mass inertia moments; 3I − third mass inertia moment; iI ,0 − i

segment mass inertia moment; im ,3 − i segment third mass; ek ,1 , 3,2k − coefficients of stiffness; eh ,1 ,

3,2h − coefficients of damping; ik ,3 , ih ,3 − coefficients of stiffness and damping of coupling; ir ,1 ,

ir ,2 , ir ,3 − radiuses of coupling; ip ,3 − gas pressure on im ,3 − mass surface; 2ϕ − turning angle of

semi-coupling two; 3ϕ − turning angle of third mass; i,0ϕ − i segment turning angle; iq ,3 − i segment third mass displacement

( )[ ( )]tii

nseg

iiiiiii qqhqqkpSrM ,0,1,1

11,0,1,1,1,1,11 && −−−+Δ−= ∑

=Σ ;

( )[ ( )]2,0,21

2,0,2,2,2,2,22 qqhqqkpSrM iinseg

iiiiiii && −−−+Δ−= ∑

=Σ ;

iiii kSp ,1,1,0,1 /=Δ ; iiii kSp ,2,2,0,2 /=Δ ; iii rq ϕ= ; iii rq ,0,0,0 ϕ=

iS ,1 , iS ,2 , iS ,3 − cross-section areas of i segment; ip ,0 − initial gas pressure in the i segment.

The equations of bodies’ movements and asynchronous engine are integrated by the trapezoid method.

The following dependences are valid according to the trapezoid method:

( )tttttt qqtqq Δ+Δ+ +Δ

=− &&2

; ( )tttttt qqtqq Δ+Δ+ +Δ

=− &&&&&&2

. (3)

Semi-couplings of a coupling are separated by real gas. Gas movement in segments is described by differential equations with partial derivates, which express laws of mass and movement quantity. One-dimensional isothermal gas movement is studied, where the gas velocity vector is directed along the axis of a segment and variables change in time and along the axis of pipeline (coordinate x ).


234

Equations of gas continuity and movement quantity are written in differential form:

0=∂∂

+∂∂

+∂∂

xv

tv

tρρρ ; (4)

01=+

Π+

∂∂

+∂∂

+∂∂

xaSx

pxvv

tv

ρτ

ρ (5)

where: ρ − gas density; v − gas velocity; τ − shearing stresses on the internal surface of the pipeline; Π − perimeter of cross-section of segment; xa − acceleration to x direction.

The equation of state of real gas is the following:

( ) RTTZp ρρ,= (6)

where: ( )TZ ,ρ − compressibility coefficient; R − gas constant; T − temperature. Having approximated the experimental data, Bogomolov and Mayer equation of the state of the

real gas is used:

( ) ∑ ∑= =

+=Ni

i

Nj

jj

T

i

ijbTZ1 0

1,τ

ωρ ρ (7)

where: crρρω ρ = ;

crT T

T=τ ; crρ − critical density; crT − critical temperature; ijb − coefficient,

Ni , Nj − variation limits. Equations of one-dimensional movement of fluid can be written as the system of second order

quasi-linear differential equations [3, 4, 5]:

[ ] ( )[ ] ( ){ }uFxuuB

tuA =

⎭⎬⎫

⎩⎨⎧

∂∂

+⎭⎬⎫

⎩⎨⎧

∂∂ , (8)

where: [ ]A , ( )[ ]uB , ( ){ }uF − matrices and vector which depend on t , x and elements iu of vector { }u . The equations of characteristics are determined by next condition:

[ ] [ ] 0det =⎟⎠⎞

⎜⎝⎛ −

dtdxAB , (9)

and equations characteristics are equal:

avdtdx

±= , (10)

where: a − sound velocity in real gas when constT = ,

( ) ⎟⎟⎠

⎞⎜⎜⎝

⎛∂∂

+=ρ

ρρ ZZRTa .

The total length of a pipeline is divided into elements, the length of which is xΔ . At the moment of time the unknown variables of task tt Δ+ : pressure p and velocity v are determined from their known values at the moment of time t Fig. 2.


235

Figure 2. The circuit of determination of gas parameters at point D

To ensure the stability of the solution, the Currant number shall be fulfilled:

1<Δ

+Δ=

xavt

Cr .

The system of two non-linear algebraic equations are obtained from conditions of compatibility on characteristics:

( ) ( ) ( )[ ] 02

1121

2121 =+Δ

−⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛+⎟⎟

⎠

⎞⎜⎜⎝

⎛−+−=Φ D

DLLDLD FFt

aappvv

ρρ; (11)

( ) ( ) ( )[ ] 02

1121

222 =+Δ

−⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛+⎟⎟

⎠

⎞⎜⎜⎝

⎛−−−=Φ DR

DRRDRD FFt

aappvv

ρρ. (12)

The parameters of gas in points L and R are obtained approximating these values between points A , C and C , B , respectively.

The system non-linear equations (10) and (11) is solved by Newton method. In the each segment’s of the coupling potential and kinetic energy of gas is transferred to the

mechanical system, which transforms this energy into kinetic and vice versa. Solving system of equations of gas movement by the method of characteristics, there are four cases of interaction between the gas flow and the solid body (Fig. 3).

In case number two the following conditions shall be fulfilled:

iHi xqx <<−1 ; iHHi xqtqx ≤⋅Δ+<−1 ; ( ) 1+<+⋅Δ+≤ iHHHi xavtqx . (13)

a) b)

c) d)

Figure 3. Cases of body and gas flow interaction: a − one, b − two, c − three, d − four


236

The system of equations in this case of interaction between gas and solid body is equal:

( )[ ] 01 =−−−=Φ FFFG pavxq ;

( ) ( ) ( )[ ] 02

1121

222 =+Δ

−⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛+⎟⎟

⎠

⎞⎜⎜⎝

⎛−−−=Φ GF

GFFGFG FFt

aappvv

ρρ;

( ) 0113 =−−=Φ GautGiGi pGvSqS ρρ & ;

( ) ( ) 0,,,441111121

14 =+−⎥

⎦

⎤⎢⎣

⎡−

Δ−−

Δ=Φ eeiiGiHHHG

iMrpSqq

tqq

trI

ϕϕϕϕ &&&&& . (14)

System of equations of interaction of gas with a rigid body for other parts of segments of the coupling similarly enters the name.

The systems of equations of motion of asynchronous engine and first mass with equations of interactions are solved by trapezoid method and obtained system of nonlinear algebraic equations is solved by Newton method:

[ ] { } { }kkk XJ 111 Φ−=Δ , (15)

where: [ ]kJ1 − Jacobi matrix; { }kX1Δ − increment vector variables

{ } [ ,,,,,,,, 11143211 GFe pxX ΔΔΔΔΔΔΔΔ=Δ ϕϕψψψψ

]TGnsegGnsegFnsegG vpxv ΔΔΔΔ ,,,...1 ,

{ }k1Φ − vector of equations; k − number of iteration. The system of equations of motion of second and third mass with equation of interactions are

solved by trapezoid method and obtained system of nonlinear algebraic equations is solved by Newton method:

[ ] { } { }kkk XJ 222 Φ−=Δ , (16)

where: { } [ ,,,, ,...1112 GnsegFnsegGGF pxvpxX ΔΔΔΔΔ=Δ ]32 ϕϕ ΔΔΔ ,,vGnseg .

3. THEORETICAL RESULTS

As an example of mechanical drive with asynchronous engine A−100S4Y3, coefficients of stiffness: 6

,1 10=ek Nm/rad, ,,13,2 ekk = 5,3,2,1 10=== iii kkk N/m, ( )nsegi ,..1= ; coefficients of

damping: 73,2,1 10−== hh e Nms/rad, 4

,3,2,1 10−=== iii hhh Ns/m, ( )nsegi ,..1= . Geometrical parameters of coupling with gas are: 12,0,2,1 == ii rr m, 045,0,3 =ir m, ( )nsegi ,..1= , 2=nseg . Inertia

moment of masses: 3106 −⋅=eI kgm2, 01,0321 === III kgm2, 01,00201 == II kgm2, 050,03 =m kg.

Dependence of semi-coupling with gas torsion angle 1221 ϕϕϕ −=Δ on time, when moment of resistance is random quantity, distributed according to the normal law is shown in Fig. 4.

The random moment of resistance is equal to:

( ) ( ) ( ) ( )[ ]

⎪⎪⎪

⎩

⎪⎪⎪

⎨

⎧

>−⋅+

≤

=

1

1221110

11

0

,sin,

,

ttwhenttMM

ttwhenttM

tM rr

r

r μσωμσ .


237

0,00

0,02

0,04

0,06

0,08

0,10

0,00 0,20 0,40 0,60 0,80 1,00

t, ms

Δϕ21, rad

Figure 4. Dependence of semi-couplings of the coupling torsion angle on time 50 =rM Nm; 51 =μ Nm; 11 =σ Nm; 902 =μ rad/s; 402 ,=σ rad/s; 101 ,t = s

4. CONCLUSIONS 1. The composed mathematical model of a drive with asynchronous engine, coupling with gas and

mechanical drive. In coupling with gas takes into account wave motion of a gas complex drive. 2. The transient’s mechanical drive is determined when resistance moment is harmonic and random

quantity distributed by the normal law. 3. Designed mathematical model of interaction of gas with a rigid body. 4. The designed mathematical model of mechanical drive is possible for using for optimization of

dynamic characteristics of this drive. References [1] Bogdevičius M. Simulation of Dynamic Processes in Hydraulic, Pneumatic and Mechanical Drivers and

their Elements. Vilnius: Technika, 2000. 96 p. [2] Bogdevičius M. Berechung Instationärer Strömungen in Elastisch − Plastischen und Visko − Plastischen

Röhrleitungen. Universität Stuttgart, 1991.48 S. [3] Bogdevičius, M. Non-Stationary Movement of Gas in Elastic Pipelines, Mechanika, No 1 (21), 2000, pp.

39-45. (Kaunas: Technologija) [4] Bogdevičius M. Simulation of Complex Pneumatic System, Transport, Vol. XV, No 1, 2000, pp. 20-28.

(Vilnius: Technika) [5] Bogdevičius M. Dynamic and Mathematical Model of Rotor System with Elastic Link in the Presence of

Shafts Misalignment. In: Proceedings 2nd International Conference of Mechanical Engineering „Mechanic’97“. Vilnius: Technika, 1997, pp. 78-84.

[6] Bogdevičius M. Simulation and Interaction of Mechanical and Hydraulic System. In: Proceedings of Tenth World Congress on the Theory of Machines and Mechanisms. Oulu (Finland), 1999, pp. 2110-2115.

[7] Bogdevičius M. Pump Hydraulic System Simulation by the Characteristic Method, TRANSPORTAS (Transport Engineering), No 2(15), 1997, pp. 30-37. (in Russian; Vilnius: Technika)

[8] Aladjev V., Bogdevicius M. Maple 6: Solution of Mathematical, Statistical, Engineering and Physical Problems. Moscow: BINOM, 2001. 850 p. ISBN 5-93308-085-X. (CD-ROM)

[9] Aladjev V., Bogdevicius M., Vaganov V. Systems of Computer Algebra: New Software Toolbox for Maple. Tallinn: International Academy of Noosphere, 2004. 462 p. ISBN 9985-9277-8-8.


238

SIMULATION OF THE INFLUENCE OF MINERAL MATERIALS’ HOMOGENEITY ON THE STABILITY OF ASPHALT CONCRETE

MIXES GRADING

Henrikas Sivilevičius1, Kęstutis Vislavičius2

1 Vilnius Gediminas Technical University Faculty of Transport Engineering, Department of Transport Technological Equipment

Plytinės Street 27-303, LT-10105, Vilnius, Lithuania Ph: (+370 5) 2744785, Fax: (+370 5) 2745060, e-mail: [email protected]

2 Vilnius Gediminas Technical University

Faculty of Fundamental Sciences, Department of Strength of Materials Saulėtekio al. 11, LT-10223, Vilnius, Lithuania

Ph: (+370 5) 2744855, Fax: (+370 5) 2744844, e-mail: [email protected] 1. INTRODUCTION

Road pavement asphalt concrete has some features of heterogeneity due to which its separate sections have worse characteristics than adjacent sections, and they deteriorate faster. Such type and range of asphalt concrete characteristics’ variation is often impacted by the instability of the used asphalt concrete mixture (ACM) composition: separate lots of the produced ACM have different quantity of the same components (crushed stone, sand, cold imported fillers, bitumen). Even if portions (batches) of highly stable mass mineral materials (3-5 hot fractions, reclaimed dust, cold imported fillers) are dosed accurately, the ACM produced in an asphalt concrete mixing plant is not homogeneous due to their segregation ([1]).

Asphalt concrete mixing plants controlled by modern computers enable to achieve sufficiently stable dosing of materials; however, ACM produced in them is not homogeneous ([2]). It shows that the homogeneity of the ACM is influenced by the variation of mineral materials’ grading used for its production.

The mathematical models constructed by us ([3,4]) enabled to reveal the impact of technological factors on the size of dispersion of each mineral component’s (crushed stone, sand, cold imported fillers) quantity. Average values of experimental investigation data obtained from the study of the composition and technological parameters of the ACM produced in seven non-computerized asphalt concrete mixing plants during one working day were used. It was found out that in the produced ACM the standard deviation value of crushed stone quantity (particles larger than 5 mm) depends by 42 % on the grading variation of the used mineral materials and by 58 % on the dosing errors; of sand (particles of 5-0,71 mm) by 70 % and 30 % respectively, cold imported fillers (particles smaller than 0,71 mm) by 60 % and 40 % respectively. These data show that the actual variation of mineral materials’ grading reduces the stability of the ACM composition at almost the same rate as their dosing errors. When very strict permissible limits of dosing materials are used in the asphalt concrete mixing plant controlled by the computer, their dosing errors may be minimized, and the stability of ACM components’ quantity may be increased. The variation of ACM components’ quantity, occurring due to the heterogeneity of the used finally dosed mineral materials, may be reduced in the asphalt concrete mixing plant hot bin by setting up anti-segregation equipment; by screening the mixture of mineral materials into a greater number of hot fractions (5, 6 or 7); by reducing their contamination with by-particles and by maintaining the constant amount of hot fractions in the sections of the bin ([3,5]).

Average values of mineral materials’ grading, obtained by taking and studying a certain number of separate samples of each material, are applied in the methodologies of designing asphalt concrete mixture of optimal composition. In fact, each mineral material is heterogeneous, and its grading varies around the mean within the interval of a certain width. When mineral materials of unstable grading are used, ACM with the different quantity of its components in separate lots is produced as well.


239

The mixture of mineral materials dried and heated in modern asphalt concrete mixing plants is screened into four or five hot fractions, the grading of which varies as well. The variation range depends on a majority of factors, and it can vary not only between separate mixing plants but in the same plant as well. According to our information, the impact of the used mineral materials’ homogeneity on the scattering of the produced ACM grading has not been studied yet. It is supposed that due to the heterogeneity of mineral materials, the designed ACM of optimal grading according to the values of screenings passing through all control sieves, complying with the requirements of standard R35-01 ([7]) will be produced so that some of its lots will not conform to these requirements: they will not be within the lower and upper permissible limits. Denying or confirming its correctness shall verify this hypothesis. Therefore, the methods of mathematical simulation are applied.

The aim of the research is to show through mathematical simulation the variation of asphalt concrete mixture grading, when per cent values of the used mineral materials’ particles’ full screenings passing through control sieves vary within the interval of different width.

The aims of the research are to obtain the curves of asphalt concrete mixture grading and to calculate statistical indices (arithmetic mean, standard deviation, dispersion, etc.) for each sieve by changing the composition of mineral materials so that the full screenings passing through control sieves complied with the normal distribution (the values of their statistical indices are known) and equal ratio materials’ mass was maintained (specified for the mixture of the designed mark). 2. SIMULATION ALGORITHM

The algorithm is illustrated by one sample of ACM grading simulation: hot ACM of 0/16-A mark is produced from seven mineral materials. The initial data of mineral materials used to produce the mixture, i.e. means X and standard deviations σ of full screenings passing through control sieves, are presented in table 1. When applying the data from the carried out experimental investigations, the following values of standard deviations are presented: minimum – minσ , medium – mσ and maximum – maxσ .

Stage one – design of the pilot asphalt concrete mixture

First of all, the pilot asphalt concrete mixture was designed, i.e. the quantity in per cent of

asphalt concrete mixture mineral materials in the mixture was estimated. To solve the problem, the mathematical analogue presented in [9, 10, 11] was used:

( )

( )

( )

( )

0

1

2 1

2 1

1

1

1

1

⎪⎪⎪⎪⎪⎪⎪

⎭

⎪⎪⎪⎪⎪⎪⎪

⎬

⎫

≥

=

=≤⋅

=≤⋅≤

→⋅

∑

∑

∑

∑

=

=

=

e,y

d,y

)c(,s,...,,v,hyd

b,n...,,,i,byab

amin,yc

j

m

j=j

m

jvjvj

imax,m

jjijimin,

m

jjj

(1)

where jc is the weight multiplier of mineral material j, jy is the quantity of mineral material j of an

asphalt concrete mixture in parts of the unit, m is the number of mineral materials, ija is the quantity of mineral material j in percent that pass through sieve i; ibmin, , ibmax, are limited quantities of a mineral part of asphalt concrete mixture in percent that can be passed through sieve i; n is the number of sieves;

vjd is the coefficient of additional inequality v corresponding to mineral material j; vh is the limit value of additional inequality v; s is the number of additional inequalities.


240

Table 1. Statistical data of mineral materials’ grading used to produce asphalt concrete mixture

Serial Mineral Statistical Size of control sieves’ mesh, mm number material index 0,09 0,25 0,71 2 5 8 11,2 16

1 Cold imported fillers X 83,6 99,4 100 100 100 100 100 100 minσ 0,60 0,02 0 0 0 0 0 0

mσ 1,15 0,11 0 0 0 0 0 0

maxσ 2,20 0,24 0 0 0 0 0 0

2 Reclaimed dust X 79,5 98,1 99,8 100 100 100 100 100 minσ 0,78 0,12 0,04 0 0 0 0 0

mσ 1,32 0,25 0,14 0 0 0 0 0

maxσ 2,71 0,32 0,24 0 0 0 0 0

3 Hot fraction 0-2 X 18,3 41,7 58,0 69,9 100 100 100 100 minσ 1,58 3,39 4,12 2,49 0 0 0 0

mσ 2,81 5,71 6,88 4,50 0 0 0 0

maxσ 4,04 8,03 9,64 6,48 0 0 0 0

4 Hot fraction 2-5 X 2,6 9,1 9,6 11,5 96,8 100 100 100 minσ 1,03 1,26 1,44 2,37 0,90 0 0 0

mσ 1,39 1,71 2,09 3,24 1,35 0 0 0

maxσ 1,75 2,16 2,73 4,12 1,80 0 0 0

5 Hot fraction 5-8 X 0,3 0,4 0,5 0,6 1,9 91,6 100 100 minσ 0,11 0,21 0,24 0,30 0,71 1,70 0 0

mσ 0,17 0,27 0,31 0,38 1,14 2,19 0 0

maxσ 0,22 0,33 0,39 0,46 1,58 2,69 0 0

6 Hot fraction 8-11 X 0,2 0,3 0,4 0,6 0,8 10,6 86,7 100 minσ 0,04 0,11 0,13 0,18 0,21 1,89 2,46 0

mσ 0,08 0,24 0,31 0,35 0,42 2,53 3,64 0

maxσ 0,12 0,37 0,49 0,51 0,62 3,16 4,82 0

7 Hot fraction 11-16 X 0,1 0,2 0,4 0,7 1,0 2,9 20,0 70,4 minσ 0,03 0,13 0,16 0,23 0,48 0,61 1,77 1,98

mσ 0,06 0,21 0,27 0,36 0,55 0,90 2,82 3,33

maxσ 0,09 0,29 0,37 0,49 0,62 1,19 3,87 4,69

The object function (1a) is a numerical

value of optimal criterion of the designed ACM mineral part. For example, if jc is the price of one mass unit of j mineral material, the numerical value of the object function equals to the price of one mass unit of ACM mineral part. Such task is usually called the task of minimal price. Inequalities (1b) limit the quantities of ACM mineral part passing through respective sieves, i. e. they express the field of solutions mathematically. The inequalities (1c) mathematically express technological limitations (there may be none of them). For example, these inequalities can be used for limitation of a maximum or minimum quantity of certain mineral material in a mixture. The equation (1c) shows that variables are expressed as parts of a unit, and the inequality (1d) guarantees the validity of solution.

Table 2. Quantities of mineral materials in the pilot ACM of 0/16-A mark

Mineral material Quantity, % Cold imported fillers 0,5 Reclaimed dust 1,3 Hot fraction 0-2 33,6 Hot fraction 2-5 17,7 Hot fraction 5-8 11,8 Hot fraction 8-11 6,8 Hot fraction 11-16 28,3

Table 3. Values of particular points of the grading curves

Sieve size,

Limit curves of ACM of 0/16-A mark, %

Pilot ACM curve, %

mm min max 0,09 3 9 8,1 0,25 7 25 17,5 0,71 15 33 23,2

2 25 40 27,6 5 36 55 53,1 8 46 68 65,5

11,2 57 80 76,5 16 90 100 91,6


241

The aim of identifying ACM mineral materials‘ quantity in per cent in the mixture was not to obtain the optimal solution according to one or another optimal criterion. The main task was to ensure that all mineral materials were used in the designed mixture since all finally dosed materials, making up the section of its largest and smallest particles, are used when producing ACM. In exceptional cases, cold imported fillers or reclaimed dust may not be used. When reclaimed dust is not used, it is stored in air purification equipment, and later is used when producing ACM of lower mark or is eliminated from the production process, for example, dumped. Since cold imported fillers and reclaimed dust are of similar grading, partial optimization task with the ratio between cold imported fillers and reclaimed dust set in advance is frequently used when selecting the optimal ratio of all mineral materials‘ mass ([8]).

When considering the possibility of using all mineral materials in the pilot mixture, inequalities of the mathematical model were of great use (1c). Versatility of this mathematical model was confirmed again. The findings of calculations are presented in table 2. Table 3 presents values of particular points of 0/16-A mark hot ACM limiting curves and the designed mixture grading curve. They show that the ACM designed according to full screenings passing through control sieves comply with all permissible limit requirements.

Stage two – simulation of full screenings passing through control sieves

The research carried out by us showed that the per cent of mineral materials‘ full screenings mass passing through control sieves distributes according to the normal distribution. It is only full screening which deviates from the normal distribution passing through the sieve with the largest mesh, where they make up ca 100 %.

In the second stage of simulation, when mean X and standard deviation σ of mineral material‘s full screening passing through control sieve are known, the theoretical function ordinate of the normal distribution (normal distribution density) is calculated and the curve is drawn:

2

2

22

1 σ

−−

⋅πσ

=

)Xx(

e)x(p . (2)

Only part of the section below the theoretical curve of normal distribution, covering 0.9973 of the normal distribution diagram area, is investigated. This part is obtained by taking away sections equal to σ3 on both sides of the mean of full screenings. Let us call part of this section the calculated section of the theoretical curve of normal distribution. Its beginning and end are the smallest and the largest values of mineral material‘s full screenings passing through control sieves:

σ−= 3min XB , (3)

σ+= 3max XB . (4)

The simulation of full screenings passing through control sieves is illustrated by the example of 0-2 mm hot fraction‘s screenings passing through 0,71 mm control sieve ( %,X 058= , %,m 886=σ ). The theoretical curve of normal distribution and its calculated section of the sieve under investigation are presented in fig. 1.

When the calculated section of the theoretical curve of normal distribution is identified, values of mineral material‘s full screenings passing through control sieve, complying with the theoretical curve of normal distribution, are calculated. The following algorithm is used.

58.0Percent passing

0.04

Dis

tribu

tion

0.020.01

0.03

0.060.05

237.4 3

1

78.6

Fig. 1. Theoretical curve of normal distribution and

calculated section of screenings passing through 0,71 mm control sieve


242

1. The area of the theoretical curve of normal distribution per one value is calculated:

nAa = , (5)

where A is the area of the theoretical curve diagram of normal distribution above the calculated section, n is the number of mineral material‘s full screenings passing through control sieve separate values set during simulation (in the example under investigation it equals to 64).

2. The following step of simulation is identified:

rBB

x minmax −=Δ , (6)

where r is any number at least 100 times bigger than n (the bigger this number is the more precise the calculation is).

3. One step ( xΔ ) is added to the smallest value of the calculated section; thus the calculated interval is obtained.

4. The central point of the calculated interval is identified. 5. The ordinate (density) of the theoretical function of normal distribution is calculated for the

central point. 6. The obtained density is multiplied by the calculated interval; thus, the calculated area is

obtained. 7. The difference between the calculated area and area a is verified. If the difference is larger

than the assumed criterion of accuracy, one-step and parts 4, 5, enlarge the calculated interval 6 of algorithm are repeated. This cycle is continued until the difference between the calculated area, compared with area a, becomes smaller than the assumed criterion of accuracy (it is accepted that the criterion of accuracy is equal to the half of the last change of the calculated area). If at the end of the cycle the value of the mineral material‘s full screenings passing through control sieve is less than zero, it is considered equal to zero; if it is more than 100, it is considered equal to 100.

8. When the difference between the calculated area and area a is less than the assumed criterion of accuracy, the last point becomes the initial point of the new calculated interval. The simulation step ( xΔ ) is added and algorithm stages 4, 5, 6, 7 are repeated. For example (fig. 1), the calculated area of the interval, the initial point of which is i, and the final point of which is (at the moment of

investigation) j, is )xx

(pa ijj/ij/i 2

−= , here j/ip – density of normal distribution, calculated for

central point (2

ij xx −) of interval ij using the formula (2).

Table 4. Hot fraction 0-2 of sieve 0,71 mm full screenings simulated values

No Value (%)

No Value (%)

No Value (%)

No Value (%)

No Value (%)

No Value (%)

No Value (%)

No Value (%)

1 40,6 9 50,5 17 53,6 25 56,0 33 58,2 41 60,4 49 62,9 57 66,3 2 44,7 10 50,9 18 54,2 26 56,3 34 58,5 42 60,7 50 63,2 58 66,8 3 46,2 11 51,4 19 54,6 27 56,6 35 58,7 43 61,0 51 63,6 59 67,5 4 47,2 12 51,8 20 54,9 28 56,8 36 59,0 44 61,3 52 64,0 60 68,3 5 48,1 13 52,2 21 55,2 29 57,1 37 59,3 45 61,6 53 64,4 61 69,2 6 48,8 14 52,6 22 55,4 30 57,4 38 59,6 46 61,9 54 64,8 62 70,3 7 49,4 15 52,9 23 55,7 31 57,7 39 59,8 47 62,2 55 65,2 63 72,1 8 50,0 16 53,3 24 56,0 32 57,9 40 60,1 48 62,5 56 65,7 64 75,9

The calculations are completed when the required number of full screenings passing through

control sieve values (n) is obtained. It is recommended to verify the obtained results by calculating the standard deviation of the obtained normal distribution. If the accuracy is not achieved, the larger number r is accepted and the algorithm is repeated. The values of full screenings of the sieve under investigation are presented in table 4.


243

Calculations are carried out for all mineral materials and all sieves by using the proposed algorithm. Therefore, before starting to simulate asphalt concrete mixtures, we have to obtain values of seven materials after 64 full screenings of each sieve. The graphs of possible grading curves’ scattering fields of all mineral materials are presented in fig. 2. Stage three – simulation of asphalt concrete mixtures

Using the generator of random numbers, the grading curve is selected for each mineral material. The condition that larger (or the same amount) of mineral material passes through sieves with larger mesh size if compared to the amount of the material passing through an adjacent sieve of smaller size, is verified. On the basis of the simulated grading curves of all mineral materials, ACM grading curve is calculated (the applied solution of the task under investigation is presented in table 2). This stage of algorithm is carried out the necessary number of times. In this work the number of such grading curves was 2000.

Table 5. Results of the calculated experiment (after 2000 iterations)

Values of special points of the simulated mixtures’ grading curves, % Sieve minσ mσ maxσ size, medium standard limited medium Standard limited medium standard limited mm deviations min max deviations min max deviations min max 0,09 8,1 0,54 6,47 9,72 8,1 0,93 5,29 10,9 8,0 1,31 4,05 11,9 0,25 17,2 1,09 13,9 20,5 16,9 1,84 11,4 22,4 16,4 2,46 8,97 23,8 0,71 23,0 1,31 19,1 27,0 22,6 2,14 16,2 29,1 21,9 2,72 13,7 30,0

2 27,6 0,88 24,9 30,2 27,5 1,54 22,9 32,2 27,5 2,15 21,1 34,0 5 53,1 0,20 52,5 53,7 53,1 0,30 52,2 54,0 53,1 0,37 52,0 54,2 8 65,5 0,28 64,6 66,3 65,4 0,38 64,3 66,6 65,4 0,48 64,0 66,9

11,2 76,4 0,50 74,9 77,9 76,4 0,81 74,0 78,9 76,4 1,08 73,2 79,7 16 91,6 0,53 90,0 93,2 91,6 0,88 89,0 94,3 91,6 1,28 87,8 95,4

a) b)

Perc

ent p

assi

ng, %

Sieve size, mm

10203040506070

9080

100

0,09 0,25 0,71 2 5 8 160

Lower limit

11,2

Upper limit

Perc

ent p

assi

ng, %

Sieve size, mm

10203040506070

9080

100

0,09 0,25 0,71 2 5 8 160

Lower limit

11,2

Upper limit

c)

Perc

ent p

assi

ng, %

Sieve size, mm

10203040506070

9080

100

0,09 0,25 0,71 2 5 8 160

Lower limit

11,2

Upper limit

Fig. 3. Grading curves’ scattering fields of pilot ACM: a) standard deviation minσ is used, b) standard deviation mσ is used, c) standard deviation maxσ is used

Perc

ent p

assi

ng, %

Sieve size, mm

10203040506070

9080

100

0,09 0,25 0,71 2 5 8 160

11,2

12

3

4 5

7

6

Fig. 2. Grading curves’ scattering fields of all mineral materials


244

Finally, arithmetic means X and standard deviations σ of full screenings are calculated for each sieve. The results of the numerical experiment are presented in table 5. Beside the values of particular points of the simulated average grading curve of the mixture, a possible distribution of such curves is presented. The table shows that standard requirements are not met on certain sieves (values of full screenings passing through control sieves which do not comply with the standard requirements are presented in bold in the table). It is obvious that the greatest number of infringements (four) is found when maximal values of standard deviations are applied during simulation. The graphs of the calculated experiment are presented in fig. 3. ACM full screenings passing through 0,71 mm control sieve are scattered within the widest range. The screening makes up 22 % and is less than 50 %. Theoretically and practically the standard deviation of screenings of particles making up 50 % of the mixture is the largest ([3,4]). Having added material dosing errors, which are bigger for larger hot fractions, the widest scattering section of the produced ACM would be similar to those particles (sieves) that make up 50 % of the mixture. 3. CONCLUSIONS

1. Due to the change of production technological parameters and raw materials’ characteristics,

poor quality of transportation, storage and delivery, mineral materials used to produce asphalt concrete mixture are heterogeneous. On a certain section their grading fluctuates around the arithmetic means of full screenings passing through control sieves. Even extremely precise dosing of stable mass heterogeneous mineral materials’ doses, the composition of separate ACM lots is not the same and varies within a certain range depending on the homogeneity of the used mineral materials.

2. Having carried out the calculated experiment with seven mineral materials of different homogeneity, complying with the real values of minimum, medium and maximum standard deviations of their full screenings passing through control sieves, it was found out that the grading of the designed ACM varies within the widest range on that section (sieve) which is made of mineral materials’ particles of the greatest variation. Particles ( %X 22≈ ) passing through 0,71 mm sieve ( %,291min =σ , %,062m =σ , %,662max =σ ) have the greatest ACM standard deviation, influenced by the heterogeneity of the used materials (without dosing errors) since the major part of it is made up of hot fraction 0-2 mm of the highest variation range. References [1] Segregation: Causes and Cures for Hot Mix Asphalt (Published by the American Association of State

Highway and Transportation Official, NAPA, 1997, 24 p.). [2] Sivilevičius H., Karalevičius I., Gailius A. Naujo kompiuterizuoto asfaltbetonio maišytuvo medžiagų

diskretinių dozatorių technologinių rodiklių statistinis vertinimas, Journal of Civil Engineering and Management, Vol. IX, Supplement 2, 2003, pp.131-140.

[3] Sivilevičius H. The Quality Improvement System of Asphalt Concrete Mixture Production Technological Process: Summary of the research report presented of habilitation. Vilnius: Technika, 2003. 37 p.

[4] Сивилявичюс Г. Ч. Моделирование однородности асфальтобетонной смеси, Наука и техника в дорожной отрасли, 2004, № 2(29), c.22-25.

[5] Sivilevičius H. The Influence of the Unloading Mode of Asphalt Concrete Mixing Plant Hot Bin on the Homogeneity of Screened Fractions, Transport, Vol. XIX, No 3, 2004, 141-147.

[6] Mix Design Methods for Asphalt Concrete and Other Hot-Mix Types: Manual Series No2 (MS-2), Sixth Edition. Lexington, USA: Asphalt Institute, 1993, 141 p.

[7] Statybos rekomendacijos R35-01. Automobilių kelių asfaltbetonio ir žvyro dangos. (Строительные рекомендации R35-01. Асфальтобетонные и гравийные покрытия автомобильных дорог) Vilnius: LAKD, 2001: 116 p.

[8] Sivilevičius H., Podviezko V. Conditional Optimization Mathematical Model Of The Asphalt Concrete Mixture Grading, Journal of Civil Engineering and Management, Vol.VIII, No 2, 2002, pp.125-132.

[9] Виславичюс К. Ю., Ясулайтис В. И. Метод проектирования оптимальных зерновых составов минеральной части асфальтобетонных смесей, Автомобильные дороги, № 9, 1987, c.8-9.

[10] Vislavičius K. Bendrieji konglomeratų fizikinių-mechaninių savybių modeliavimo principai, Statyba, Vilnius, VI t., No 3, 2000, 175-178.

[11] Vislavičius K. Determination of Optimum Quantity of Bitumen on Asphalt Concrete Mixtures, Journal of Civil Engineering and Management, Vilnius, Vol. VIII, No 1, 2002, pp.73-76.


245

THE RESEARCH ON THE INFLUENCE OF THE EXTERNAL EXCITATION CHARACTERISTICS ON THE DYNAMIC

“MAN – WHEELCHAIR – VEHICLE” SYSTEM

Mečislovas Mariūnas1, Julius Griškevičius2

Vilnius Gediminas Technical University,

Faculty of Mechanics, Department of Biomechanics J.Basanavičiaus Str. 28a, LT-03224, Vilnius, Lithuania

Ph: (+370)-5-2744748. Fax: (+370)-5-2745043. 1 E-mail: [email protected], 2 E-mail: [email protected]

INTRODUCTION

Safe transportation of the wheelchair-seated passengers nowadays is one of the most important

problems facing transit providers and engineers. In a public transport disabled individuals often sit in their wheelchairs, therefore there must be certain means for securing the wheelchairs. Wheelchair is not typically designed to function as motor vehicle seat and it must be tested to withstand high loads that may occur during different traffic accidents [1, 2]. Because of the high traffic intensity, complex structure of the street system, non-uniform quality of the pavement, particularity of the public transport route the motion in the city is the most changeable, non-steady regime [3, 4]. During such motion high accelerations and forces act on the passengers, and therefore it is essential to determine magnitude of the dynamical loads and their influence on the wheelchair-seated passengers’ safety during the travel. Despite the fact that the transportation safety of wheelchair-users and wheelchair crashworthiness problems has been solved partly by implementing the standards (ISO, ANSI/RESNA, FMVSS) for different wheelchair tie-down occupant restraint systems, some problems still exist [5, 6]. For example, wheelchair tie-down occupant restraint systems are not installed in all public transport and are often difficult to reach, uncomfortable to wear, and time-consuming to use [7]. Improperly or totally unsecured wheelchair can lose the stability and may become dangerous during an accident or emergency braking, especially the heavier electrical wheelchair. Furthermore, in the event of rollover the passenger should not be allowed to fall out of his wheelchair. However, if this should occur, the wheelchair itself should not be allowed to tumble on the passenger or through the bus during an accident. Most injuries to wheelchair users riding the city transport seem to result not from the traffic accident but more from sudden braking and turning that bus drivers do during daily routs in the city streets [8, 9]. Often disabled person travels seated in his wheelchair during the long-distance travel outside the city. When the wheelchair is rigidly fixed on the vehicle floor, vibration caused by different sources (road roughness, engine vibration) is directly transmitted to the body and therefore passenger may feel discomfort [10]. Therefore it is essential to determine whether the resonant frequencies of the vehicle cover the frequency range from 1 to 15 Hz, wherein human body mostly feels the discomfort. Most wheelchair restraint devices are designed primarily to prevent the wheelchair and the wheelchair occupant from moving excessively in a transportation situation and [11, 12].

Thus the main objectives of present paper are to determine characteristics of the external excitation during the motion of the vehicle and their influence on to dynamic “Man – Wheelchair – Vehicle” system, and to provide certain means to reduce negative effects on the safety and safe transportation of wheelchair-seated disabled persons.

MATERIAL AND RESEARCH METHODS

Since the wheelchair-seated passenger is in the moving vehicle, it is essential to determine

external excitation forces that occur during the vehicle’s motion. In turn the motion of the vehicle can be divided into the steady and non-steady motion regimes. During the steady motion transport mean is riding at a constant velocity, without sharp maneuvers, therefore forces of the kinematic or other sources of excitation are small. Non-steady regime of the motion is more dangerous, because sharply


246

varying speed and/or path increases the loads like accelerations which in turn cause the reduction of the stability and therefore safety of the wheelchair-seated disabled person. Furthermore, because of high traffic intensity, complex structure of the street system, non-uniform road surface, and traffic jams, unexpected accidental situations, and particularity of the public transport daily routes in the city are exactly the non-steady regime of the motion. Consequently, analyzing the daily routes of the public transport can be distinguished specific and frequently repetitive motion regimes. They are: start moving and stopping in bus-stops, in traffic jams, high radius turnings, different maneuvers and so on. Thus, series of experimental measurements in most widely usable public transportation means (busses, trolleys) were performed. Accelerations in three directions, which affect the disabled person in the wheelchair during before mentioned vehicles driving regimes, were recorded using “Bruel&Kjaer” portable PULSE Type 3560C 4/2-ch. Input/Output module Type 3109. Tri-axial accelerometer was mounted on the plate and attached to the floor of vehicle, in special space for the disabled passengers with the wheelchairs. Usually it is located in the middle of the low-floor passenger bus or trolley. The setup of the experimental measurements in moving vehicle is shown schematically in Figure 1.

1

23

xy

z

(Drivingdirection)

Fig.1. Setup of the experimental measurements

1 – Accelerometer; 2 – Portable data acquisition system; 3 – PC with analysis software

Shapes of the measured acceleration pulses during most common motion regimes of the public transport are shown in Figure 2 on the left. Peak values of the acceleration produce significant large forces acting on the wheelchair-bound disabled person and the stability of the dynamic “Man – Wheelchair – Vehicle” system reduces. Large accelerations that occur during traffic accidents are very dangerous and can cause severe or fatal injuries of passengers. Form and duration of the acceleration pulse determines the severity of the dynamical loads during the motion of the vehicle.

Fig.2. Measured acceleration pulses during different motion regimes (on the left)

and acceleration pulse during tug-like motion of the vehicle (on the right)


247

The motion regimes of the public transport and ranges of the measured acceleration values in terms of gs are listed in Table 1.

Table 1. Acceleration values

Acceleration values, g’s Nr. Motion regime min max 1. Start moving 0.508 0.653 2. Braking (from ~30–40 to 0 km/h) 0.570 1.394 3. U-turn (~20–30 km/h with ~20m radius turn) 0.639 1.156 4. Different maneuvers 0.594 0.724 5. Route cycle through the city streets 0.356 0.869 6. Unexpected tug-like motion – 1.825

The speed in the city is limited up to 50-60 km/h and often it is lesser (average speed is about

30-40 km/h) because of the traffic intensity and street structure. Therefore severe collisions are very rare and disabled person travels in so called “low-g” environment, where acceleration loads are up to 2 g’s in comparison with the accelerations up to 30 g’s when the car crashes into a wall at speed ~54km/h for example. Particular cases in driving regimes that occur occasionally but nevertheless are significant should be marked. It is the regime when the bus or other mean of transportation suddenly changes its state of motion. For example, it can be an emergency braking or tug-like motion of the vehicle. The nature of acting forces during such motion is impulsive, with high amplitudes and short duration. Figure 2 on the right shows acceleration pulse of the tug-like motion.

Together with the measurements of accelerations during the most common driving regimes also the vehicle’s accelerations during the usual route in the city streets were recorded. Figure 3 shows the accelerations during the 5 minutes long driving cycle.

Fig.3. Measured accelerations in three directions during the route in the city

Four intervals can be distinguished from the obtained acceleration data for the separate analysis.

First interval lasts from 0 to 60 seconds (Fig.3. No.1), the bus starts moving from one bus stop to the next and stops there. Acceleration ax coincides to the bus driving direction, ay to the lateral movements in horizontal direction and az to the vertical. Second interval lasts from 70 to 150 seconds (Fig.3. No.2) and the bus moves again from one bus-stop to the next. Third interval lasts form 160 to 220 seconds (Fig.3. No.3), and the bus starts from a bus stop and stops in a traffic jam. Fourth interval (Fig.3. No.4) depicts the jerk of the bus in a traffic jam. Acceleration data was recorded and represented in time domain. Common practice is to present data in frequency domain, because the frequency spectrum gives more detailed information about the signal sources that cannot be obtained from the time signal and for this study especially important are the frequencies in lowest range. For this reason spectral analysis of the acceleration data using discrete fast Fourier transformation and Matlab software was performed.

Figure 4 shows the estimated power spectral densities (PSD) of the measured acceleration data during before mentioned cycle intervals.

1 2 3 4


248

Fig.4. Power spectral density graphs of the measured acceleration

The spectral analysis of the frequencies spectrum of the system‘s accelerations showed 3

dominant groups in it: 0–80 Hz; 300–500 Hz and 750–950 Hz. However, amplitudes of vibrations, matching the second and the third groups are very small and can be assigned to the structure of vehicle body, working engine and similar sources. To depict clearly the range of lowest frequencies logarithmic scale was chosen, because the effect of the lower frequencies to the disabled person in a wheelchair is very significant. On purpose to determine whether the frequencies of the external excitation in the lowest range from 0 to 80 Hz cover the natural frequencies of the wheelchair-seated disabled person, the spectral analysis of the “Man – Wheelchair” subsystem was performed. The wheelchair was chosen a manual rear-wheel-driven wheelchair, which is the most common (Fig. 5, on the left). Furthermore, the stiffness characteristics of the wheelchair were measured experimentally and the relationship between the stiffness and the pressure in the wheelchair tyres for different loading situations is shown in Figure 5 on the right.

xy

z

1

2

3

Fig.5. Disabled person in the wheelchair and measurement setup (on the right) and stiffness dependence

on the pressure values in the wheelchair tyres (on the right) 1 – Accelerometer; 2 – Portable data acquisition system; 3 – PC with analysis software

1 2

3 4


249

In Figure 6 are shown the power spectral densities graphs of the wheelchair-seated disabled person in three directions x (Fig.6, 1), y (Fig.6, 2) and z (Fig.6, 3) in comparison with the frequency spectrum of the vehicle during the emergency braking from the velocity 40 km/h to full stop of the bus.

Fig.6. Power spectral densities of the wheelchair-seated disabled person in comparison

with the vehicle’s during an emergency braking

Analyzing the frequency spectrums of the vehicle during the full cycle motion in the city (Figs. 3 and 4) and during an emergency braking situation (Fig.6) it can be marked that the lowest range of well-defined frequencies is in vertical and lateral directions. It can be marked coincident resonant frequencies peaks of the vehicle and the wheelchair – seated disabled person in the range from 1 to 15 Hz. In vertical direction resonant frequencies are at 5 Hz, 7 Hz and 13 Hz; in lateral (y) direction at 4 – 5 Hz and 8 Hz. And the more sudden the vehicle changes its state of motion (for example, emergency braking, tug-like motion and similar), the more emphasizes the lowest frequencies with higher amplitudes. Therefore the stability of the dynamic “Man – Wheelchair – Vehicle” (MWV) system can decrease especially in vertical and lateral directions. Thus it can be distinguished three possible cases of the dynamic MWV system behavior; they are the steady motion, partial and complete abruption cases (Fig. 7. 1, 2 and 3).

Fig.7. Possible cases of the dynamic “Man – Wheelchair – Vehicle” system’s behavior

1

3

2

321


250

The research was made on the system consisting of two bodies (the man and the wheelchair) with concentrated masses m1 and m2 respectively (Fig. 8). The dynamic MWV system is connected to the vehicle through elastic constraints in one point (Fig. 8, point “F”) with coordinate’s ht and Lt. The disabled person is bound by elastic constraints only to the wheelchair.

Fig.8. The simplified model of the wheelchair-seated disabled person

The man in a wheelchair and the wheelchair each has 6 degrees of freedom; therefore using the

LaGrange’s energy method the system of 12-second order non-linear differential equations that describes the steady motion of the system was obtained. The equation of motion is shown using generalized coordinates:

[ ]{ } [ ]{ } [ ]{ } { } ,M q C q K q Q+ + =&& & (1)

where M is the mass matrix, C is the dissipative matrix, K is the stiffness matrix, Q is the column vector of the generalized external forces and { }q , { }q& , { }q&& are the column vectors of the generalized translational and rotational displacements, linear and angular velocities and accelerations respectively.

The wheelchair’s vertical displacement z2 in vertical Oz direction and the angle of rotation φ2 around the Oy axis are the primary parameters that determine the stability of the dynamic MWV system. System’s stability is described by the relationships of the static deformation between the wheelchair tyres and vehicle’s ground and dynamic MWV system’s behavior under different loading situations. The value of static deformation zst (Fig. 9) is determined basically by the experimentally measured stiffness characteristics of the wheelchair’s tyres and it is non-linearly dependent on the pressure in the tyres.

Load

z'o

zo

Fig.9. Value of the static deformation between the wheelchair tyres and vehicle’s ground


251

Thus, during the steady motion regime of the MWV system the stability is defined by following inequalities:

2

2 2 2 2

,

and ,2 2

st

p pst st

z zL L

z z z zϕ ϕ

≤⎧⎪⎨

+ ≤ − ≤⎪⎩

(2)

where Lp is the width between the wheelchair’s wheels, z2 is the vertical displacement and zst (zst = zo – z’o) is the static deformation between the wheelchair’s tyres and vehicle’s ground.

When the vehicle is moving under extreme conditions, for example sudden braking or sharp turning, higher accelerations act on the disabled person in the wheelchair and following inequalities for the dynamic system’s behavior cases (Fig. 7, 2 and 3) exists respectively:

2

2 2 2 2

,

and ,2 2

st

p pst st

z zL L

z z z zϕ ϕ

>⎧⎪⎨

+ > − ≤⎪⎩

(3)

2

2 2 2 2

,

and .2 2

st

p pst st

z zL L

z z z zϕ ϕ

>⎧⎪⎨

+ > − >⎪⎩

(4)

When the conditions (3) or (4) are fulfilled, the tyres of the wheelchair lose the contact with the vehicle’s ground and the wheelchair is restrained only at one fastening point. Thus, the frame of reference changes, sets of elastic constraints intermit and the motion of the dynamic MWV system is described by other systems of equations. When the condition (2) in the considered system’s motion is fulfilled again, an impact occurs between the wheelchair’s wheels and the vehicle’s ground. Very large accelerations that exceed the stability limit of the MWV system can cause more complex gross motion of the system. Therefore, the analysis of the dynamical system’s motion is performed using the numerical methods.

Another significant parameter can be expressed as the ratio S of the fastening height ht and the center of gravity of the system:

t

CG

hS ,

H= (5)

where ht is the fastening height and HCG is vertical coordinate of the system’s center of gravity. The fourth-order Runge-Kutta method with fixed time step was chosen as a numerical method

to solve system (1) of non-linear differential equations. Series of calculations were performed to determine the response of the system and to establish how fastening height influence on the overall stability of the dynamic “Man – Wheelchair – Vehicle” system. Gradually increasing the acceleration pulse magnitude and ratio S, the obtained dependencies are shown in Fig. 10. For a man with the weight m1 = 80 kg (load 800 N) sitting in the wheelchair, the magnitude of static deformation value zst equals to ~8 mm. Thus, when a vertical displacement z2 of the wheelchair exceeds zst, the motion of the system must be described by another system of equations.

Fig.10. Angular (1) and vertical (2) displacements, tyre pressure pmax = 0.32 mpa

21


252

When the pressure in the wheelchair tyres is low, large accelerations increase the amplitudes of vertical displacements of the MWV system 1.2 times, and vice versa, vertical displacements are smaller when the tyre is stiffer. Thus, the stability condition (2) is satisfied with lower pressure values for smaller accelerations. Fig. 10, 2 shows gradually growth of vertical displacements independent of the wheelchairs’ fastening height. Analyzing the angular displacements about the Oy axis it can be seen, that amplitudes of the rotations are growing during the increase of the accelerations. However, depending on the fastening height, largest values will be at lower ratio S values of the fastening height and the height of center of gravity. It was also determined that when the accelerations exceed 25 m/s2, motion of the system cannot be described by the system (1) of equations because the frame of reference has changed and the amplitudes of oscillations increased. Taking in to account measured accelerations during daily routes of the public transport, it can be seen that the peak of values is up to 18 m/s2 and therefore the motion of the dynamic “Man – Wheelchair – Vehicle” system lies within the stable region. CONCLUSIONS

The main findings of the present research of the external excitation influence on the dynamic “Man – Wheelchair – Vehicle” system are listed below.

1. Measurements showed that the largest accelerations in terms of g’s were up to 1.4 g’s during the emergency braking from the velocity 40 km/h to full stop; during the full left-right-turns up to 1.2 g’s and other regimes from 0.4 to 0.9 g’s. During an unexpected jerk of the vehicle largest acceleration up to 2 g’s was measured. Therefore the disabled person travels in so called “low-g” environment and in spite of the loads are small in comparison with high loads (up to 30 g’s) during severe car crashes there must be certain means to safely secure the wheelchair.

2. The spectral analysis of the spectrum of the “Man – Wheelchair – Vehicle” system’s accelerations showed 3 dominant groups in it: 0-80 Hz, 300-500 Hz, and 750-950 Hz. However, amplitudes of vibrations, matching the second and the third groups are very small and depend mainly on the vehicle’s body structure, engine action. More significant is the lowest range of the frequencies, because the natural frequencies of the disabled person in a wheelchair are very low and lie in range of 1-15 Hz. Thus the frequencies of the vehicle and wheelchair-seated disabled person were superposed and coincident resonant frequency peaks of the vehicle and wheelchair – seated disabled person in the range from 1 to 15 Hz were noted: in vertical direction at 5 Hz, 7 Hz and 13 Hz; in lateral direction at 4 – 5 Hz and 8 Hz. The superposition effect of the resonant frequencies in considered public transportation case is minor, because the trip through the city usually is of small duration, with often stops; however during the long-distance trips mentioned phenomena may be the cause of the ride discomfort.

3. Numerical analysis showed that the condition of the wheelchair tyres to lose contact with the vehicle’s ground fulfilled when the acceleration exceeds 25 m/s2. The frame of reference is changed and therefore another system of equations for the analysis of MWV system’s stability is required.

4. Observed, that the fastening height of the wheelchair to the vehicle is also very important. Decreasing the fastening height 3 times, rotation amplitudes about an Oy axis increased 2.1 times thus resulting in the decrease of the dynamic system stability. The fastening device of the wheelchair to the transport mean must have an ability to change the mentioned dimensions and must be adjusted to each disabled person individually, that is safe, comfortable and allows independent usage.

5. Pressure magnitude in the wheelchair tyres has the significant influence on amplitudes of oscillations in the MWV system. When the pressure in the wheelchair tyres is diminished 3 times, the amplitudes of oscillations increase 1.2 times at the same parameters of the dynamic system. Last-mentioned phenomena indicates that despite lowered stiffness is more effective in the reduction of the ground vibrations, during braking and turning increased acceleration forces act directly on the MWV system resulting in the increase of the angular displacements especially. References [1] Bertocci G.E., Manary M., Ha D. Wheelchairs Used as Motor Vehicle Seats: Seat Loading in Frontal

Impact Sled Testing, Medical Engineering & Physics, 23(10), 2001, pp. 679-685.


253

[2] Ha D., Bertocci G.E., Karg P., Deemer E. Evaluation of Wheelchair Sling Seat and Sling Back Crashworthiness, Medical Engineering & Physics, 24(6), 2004, pp. 441-448.

[3] Mariūnas M., Griškevičius J. The Analysis of the Impact-Dynamic “Man – Wheelchair – Vehicle” System, Proceedings of XIV International Symposium “Research, Practice and Didactics in modern Machine Building”, Stralsund, Germany, May 5-8, 2004, pp. 52-60.

[4] Mariūnas M., Griškevičius J. The Analysis of Natural Frequencies of Dynamical System “Disabled Person in a Vehicle” In: Proceedings of Scientific-Practical Seminar BIOMDLORE‘03(4) “Biomechanics, Artificial Organs, Locomotion, Orthopedics, Rehabilitation”, Vilnius, Lithuania, October 9, 2003, pp. 89-95.

[5] Van Roosmalen L., Bertocci G.E., Ha D., Karg P. Wheelchair Integrated Occupant Restraints: Feasibility in Frontal Impact, Medical Engineering & Physics, 23(10), 2001, pp. 687-698.

[6] Shaw G., Gillispie T. Appropriate Protection for Wheelchair Riders on Public Transit Buses, Journal of Rehabilitation Research and Development, 40(4), 2003, pp.309-320.

[7] Van Roosmalen L., Bertocci G.E., Hobson D.A., Karg P. Preliminary Evaluation of Wheelchair Occupant Restraint System Usage in Motor Vehicles, Journal of Rehabilitation Research and Development, 39(1), 2002, pp. 83-93.

[8] Van Roosmalen L., Bertocci G.E., Herring D. Wheelchair and Occupant Kinematics During “Low-G” Turning and Braking. In: Proceedings of RESNA 26th Annual Conference. Atlanta, GA, June 2003.

[9] Wretstrand A., Petzäll J., Ståhl A. Safety as Perceived by Wheelchair-Seated Passengers in Special Transportation Services, Accident Analysis & Prevention, 36(1), 2004, pp. 3-11.

[10] Kawai K., Matsuoka Y. Construction of a Vibration Simulation Model for the Transportation of Wheelchair-Bound Passengers. In: SAE 2000 World Congress. Detroit, Michigan, March 6-9, 2000. SAE technical paper Nr. 2001-01-0645.

[11] Mariūnas M., Griškevičius J. Influence of the Wheelchair Fastening Characteristics on the Stability of Dynamic „Man – Wheelchair – Vehicle“ System, Mechanics (Kaunas, Lithuania), 3(47), 2004, pp. 38-44.

[12] Mariūnas M., Griškevičius J. The Analysis of the Impacts Influence on the Dynamic “Man – Wheelchair – Vehicle” System. In: Proceedings of International Conference “Biomechanics 2004”, Gdańsk, Poland, September 9-11. Acta of Bioengineering and Biomechanics, Vol.6, Supplement 1, 2004, pp. 100-104.

Efficiency of Electronics Systems and Devices


255

IDENTIFICATION OF NARROW-BAND DISCRETE SYSTEMS

V. Yeremeyev, Т. Mamirov

Transport and Telecommunication Institute Lomonosov Str. 1, Riga, LV 1019, Latvia

Ph: (+371)-9499489. Fax: (+371)-7100660. E-mail: [email protected] 1. INTRODUCTION

Modern digital signal processing makes very strict demands to the filtration systems. Ones of them are high selectivity and narrowness of band.

Traditional bi-quad realizations [3] are not enough robust and also provide relatively low narrowness of band. Practically realizable normalized pass bands of a digital low pass bi-quad filter are only about 10-4-10-7( Ω~ ). However, some practical applications, for example, in systems of artificial sense of smell, demand higher resolution of frequency components. Earlier by authors the new bi-lines digital structures have been offered, possessing super-narrowness of band - till 10-15. The detailed analysis of such structures is given in the literature [2, 3].

Identification of bi-line structures in real time is extremely problematic. The traditional way of an estimation of dynamic frequency characteristics by the impulse response in this case is inconvenient because of its excessively big required length. It does not allow investigating frequency characteristics with necessary accuracy with the help of Fourier discrete transformation. The last causes practically unpredictable errors because of insufficient precision of machine arithmetic and excessively big number of required arithmetic operations. 2. DESCRIPTION OF THE RESEARCH

In this work the new technique of recursive systems identification is offered. It is based on synthesis of special finite input test influences, at which reaction of correctly designed filter has strictly limited duration.

As a base, we shall consider a transfer function of the digital filter in Z-area:

NN

NN

zbzbzazaa

HzH −−

−−−

++++++

=K

K1

1

110

01

1)( (1)

and formulate the next theorem.

Theorem. For identification of any discrete N-order IIR-system it is always possible to generate an input influence with duration no more, than (N+1) samples, at which the finite length of output sequence is guaranteed.

The proof. Really, the output response of any IIR-system of the finite order is:

)()()( 111 −−− ⋅= zXzHzY .

If this product is a polynomial of 1−z , it is enough, that the reaction of such system will be finite length. It is possible only in a case, when X(z-1) is equal to a polynomial of a transfer function denominator. At such input influence the Z-image of IIR-system reaction will be equal to numerator of transfer function, which is finite by definition.

For identification of the unknown system, having, in general, transfer function (1), generating of input unique sequence consists of samples selection of input influence, until output response becomes finite. After determination of both sequences a system’s transfer function automatically becomes known. Then it is possible to calculate system frequency characteristics and to draw a conclusion about theirs compliance with goal requirements.


256

The offered method is especially useful for super narrow-band systems identification. We shall consider the bi-line structure, which transfer function is described by expression:

=⎟⎟⎟

⎠

⎞

⎜⎜⎜

⎝

⎛

+−

+−−⋅

+−+−−

=−−

−−=

+++

= ∏∏∏= −

−

−

−

==

2

1 1*

2

1**

11

1

21

2

1*

*2

12

2

)(1

)()()(1

)()(

))((

))(()(

N

iiio

ii

iio

iiioio

N

iii

ii

N

i ii

i

zpkh

zzkzkzpkh

zzkzkhh

pppp

zpzpCpBp

AppH

∏= −

−

−

−

⎟⎟⎟

⎠

⎞

⎜⎜⎜

⎝

⎛

−

−⋅

−−

=2

1 1*

1*

1

*

01

110

11

N

ii

ii

i

iio

z

zbbzzbb

hαα

. (2)

For identification of this bi-line system it is expedient to form an input influence, which Z-transformation is equal to polynomials’ product of denominators. In this case, while forming of input sequence the system’s poles in Z-area (αi) are selected. 3. EXAMPLES

Let's make identification1 of elliptical bi-line filter, order of which is known (N=14). The theoretical impulse characteristic of such system is shown on fig. 1.

Fig. 1. Impulse response of bi-line elliptical filter (N = 14)

Unique input influence ∏=

−− −−=2

1

1*

1 )1)(1(N

kiiin zzX αα of the minimal length we shall determine

either by random search of all poles αi, or, that is certainly better, using known evaluated initial approach - with the help of methods of local optimisation.

As a result of the described identification process, the input influence of (N+1) samples length is determined (for presentation samples are resulted with the limited precision) (fig. 2):

Xin = 1*103*[0.0010 -0.0140 0.0910 -0.3640 1.0010 -2.0020 3.0029 -3.4319

3.0029 -2.0019 1.0010 -0.3640 0.0910 -0.0140 0.0010]

1 Modelling of all processes was carried out on Pentium 4 2.4 GHz, 1 Gb RAM under OS Windows XP Professional, environment - Matlab 6.5 Release 13.

0 1000 2000 3000 4000 5000 6000-6

-4

-2

0

2

4

6

8x 10

-3

Sample time

Am

plitu

de

Impulse response of biline structure

2.58 2.585 2.59 2.595 2.6 2.605 2.61 2.615 2.62

x 105

-4

-3

-2

-1

0

1

2

3

4x 10

-56

Sample time

Am

plitu

de

Impulse response of biline structure


257

Fig. 2. Formed input influence

The system response is certainly finite (fig. 3):

Yout = [0.0010 -0.0141 0.0904 -0.3586 0.9798 -1.9506 2.9179 -3.3317 2.9179 -1.9506 0.9798 -0.3586 0.0904 -0.0140 0.0010]

Fig. 3. Response of elliptical filter on special input influence

During system’s identification in real time it’s important not only to receive amplitude-frequency response (AFR), meeting the set requirements. In particular, sometimes it is necessary to analyse, in what degree allowable (by criterion of stability) random deviations of transfer function’s poles influence on AFR’s form and on target reaction. For example, we should add uniform noise N0 to poles, so that in result they remain inside unit circle on Z – plane:

)"1()'1( 00 NjNp iii +++⋅= βα , 1≤ip .

0 2 4 6 8 10 12 14 16 18 20

-3000

-2000

-1000

0

1000

2000

3000

Sample time

Am

plitu

de

Special test influence

0 5 10 15 20 25 30-8

-6

-4

-2

0

2

4

6

8x 10

-6

Sample time

Am

plitu

de

Impulse response of special test influence

2000 4000 6000 8000 10000 12000 14000 16000

-5

-4

-3

-2

-1

0

1

2

3

4

5

x 10-13

Sample time

Am

plitu

de



258

On fig. 4, 5 the example of the selective system’s identification with the added random additive polar noise about 10-2 % is shown. Apparently, output response, as expected, is finite; however "identified" AFR in a pass band is significantly distorted.

Fig. 4. Poles and zeros arrangement of elliptical bi-line filter and it’s AFR

Fig. 5. Test response of “noised” filter

Let's consider a possible defragmentation of identification process in case of parallel program realization, with an opportunity of reception of separate sub-channels responses. Transfer function can be presented so:

⎟⎟⎟

⎠

⎞

⎜⎜⎜

⎝

⎛+

⎟⎟⎟

⎠

⎞

⎜⎜⎜

⎝

⎛

−+

−=

−−

++=

++++

= ∑∏∏= −

−= −−

−−

=−−

−−− 1

11)1)(1(1)(

2

1 1*

**

1''

0

2

1 1*

1

22

110'

0

2

12

21

1

22

110

01

N

kk

kk

k

kk

N

kkk

kkk

N

k kk

kkk

zz

zKzz

zKH

zzzz

zbzbbH

zazazbzbb

HzH . (3)

0.992 0.994 0.996 0.998 1 1.002

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

Real part

Imag

inar

y pa

rt

Zero-pole reprezentation of elliptical filter

0 0.005 0.01 0.015 0.02 0.025 0.030

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Digital frequency, Ω

Mag

nitu

de

Amplitude-frequency response of biline filter

0 5 10 15 20 25 30-8

-6

-4

-2

0

2

4

6

8x 10

-6

Sample time

Am

plitu

de



259

Apparently from expression (4), each part of the sum can be identified separately. In that case the problem of identification is paralysing and is technologically carried out faster in real time. It is enough to send the minimally short test complex sequence (two inputs - real and imaginary) on each sub-channel. Summarizing responses, it is possible to start an estimation of all transfer function. 4. CONCLUSIONS

The new method of identification of recursive, in particular, narrow-band systems is suggested. The examples of system identification with parameters are shown.

References [1] Оппенгейм А.В., Шафер Р.В. Цифровая обработка сигналов. Москва: Связь, 1979. [2] Мамиров Т. Цифровые фазовые звенья с комплексными умножителями, Transport and

Telecommunication, 2003, с. 75. ISSN 1407-6160 [3] Еремеев В., Мамиров Т., Гуменюк А. Новые структуры малочувствительных цифровых фильтров,

Computer Modeling and New Technologies, 2001, с.145. ISSN 1407-5806. [4] Антонью А. Цифровые фильтры: анализ и проектирование. Москва: Радио и связь, 1983. 320 с. [5] Рабинер Л., Гоулд Б. Теория и применение цифровой обработки сигналов. Москва: Мир, 1978. 848 с.


260

SHORT WAVE COMMUNICATION LINES EFFICIENCY INCREASE IN CIVIL AVIATION

Alexander Mrochko, Yury Sikerzitski, Vladimir Shelkovnikov

Transport and Telecommunication Institute Lomonosov Str. 1, Riga, LV-1019, Latvia

Ph: 7100573. E-mail: [email protected] INTRODUCTION

Rapid development of satellite communication systems has resulted in an undeserved reduction of work on improving the already existing radio-communication lines, particularly, short wave communication lines in civil aviation used as the reserve ones in emergencies of aircraft.

One of the problems incurred in the organization of communication with aircraft is low disturbance tolerance and unreliability of communication between radio-stations located in the range distance from 50km to 200 km from each other.

The energy calculation of such communication lines has shown that the information supply of aircraft in the short wave range mode will be possible provided that antennae of zenithal radiation and reception effect radiation and reception of signals.

The requirements on parameters of short wave antennae of zenithal radiation and reception have been formulated on the basis of energy calculations. FERRIC-ELECTRICAL ANTENNAE

The attempts to raise the efficiency of radiation of short wave antennae of aircraft are pretty difficult because the field made by the antenna of an aircraft is to a great extent reduced by the almost anti-phase field made by the hull of the aircraft.

To reduce the influence of the anti-phase field of the fuselage of an aircraft, it is suggested to use ferric-electrical antennae in which either some ferric or a ferric antenna are used to initiate electric currents in the metallic surface of the radiator and this enables to form special amplitude-phase distributions of electric current, for example, in the fuselage of an aircraft. The following types of ferric-electric antennae are suggested and studied:

1. To form the amplitude distribution of electric currents in the fuselage of an aircraft, you can use a ferric antenna. This ferric-electrical antenna was constructively developed and theoretically studied. Its main advantage is a much greater efficiency as compared with an ordinary ferric antenna. Therefore, unlike the ferric antenna, it can be used not only for reception but for transmission as well.

In this case the surface of the airplane fuselage is used for radiating the electromagnetic waves by exciting on it the conductivity currents eliminating the necessity to use special current-carrying conductors in comparison with the usual electrical antenna.

2. Another option of a ferric-electrical antenna for the required phase distribution of electric currents in the fuselage of an aircraft suggests a magneto-dielectric layer between the antenna and the hull of an aircraft. In this antenna system you can make use of the electromagnetic field re-reflected by the fuselage.

In this case the magneto-dielectric layer with the corresponding parameters should cover the fuselage. This layer will cause the additional regulated shift of the phase of the components of the fuselage re-radiated electromagnetic field. Thus, in the observation point the compensation of the fields provided by the vibrator and fuselage will not be formed and this fact will naturally lead to the growth of the efficiency of the zenithal radiation antenna system (electrical vibrators – the airplane fuselage with the magneto-dielectric layer).

Besides, provided that the appropriate choice of the magneto-dielectric layer parameters is made, the electrical and magnetic fields magneto-dielectric layer tension in the zenithal direction of this system can be increased in comparison with the single electrical vibrator of the same length.


261

The authors of the article have developed the analytical expressions of the tangential constituents of the electric Eτ and magnetic τH fields on the surface of the magneto-dielectric layer [1].

⎟⎟⎠

⎞⎜⎜⎝

⎛

−+

+−

+−

++= ψ

ψψ

ψ

τ ψψ cos1

sincos1

sin2

cos21cos2160 p

parctg

pp

ctgaj

zв e

PPPP

dI

Er

dIH вπτ 2

= ,

where IВ – the electrical current in the vibrator; d – the distance from the electrical vibrator wire to the magneto-dielectric layer with h thickness;

,P ψ – correspondingly the module and the phase of the reflection coefficient being the complex function of the magneto-dielectric layer [1] parameters.

With the help of these expressions we can find the fields E and H as a result of the re-radiating of the fuselage with the magneto-dielectric layer at any point of the space.

3. The third option of the antenna system suggests using an absorbing layer between the vibrating antenna and the hull of an aircraft. It will result in reduction of the field re-reflected by the fuselage. RECEIVING FERRIC ANTENNAE GRID

Anyway, even with the above transmitting antenna systems, the signal at the point of reception might be pretty feeble. Therefore, at the receiving side, it is suggested to use a grid of receiving ferric antennae.

The peculiarity of performance of the receiving antenna system of the decimal-meter range waves is that the electrical-magnetic wave, reaching the place of the system installation, fluctuates both in the amplitude and in the phase.

The resulting diagram direction of the above system will be defined by the average, in the statistic sense, interference multiplier of the grid [2] for which calculation you need to know the statistic characteristics of the received signal.

On the basis of the experimental data on the statistic signal characteristics for trajectories up to 1000 km [3] the authors have developed the expression for an interference multiplier of the grid working in the conditions of fluctuations of the amplitude and the phase of the received signal with reference to relatively short radio lines:

( )

,2

22

,A

dm

mK ρκ−−

κ = e ( )

,K2

22 dm

m,ϕρ

κ−−

κ =′ e

( )

,12

221

2max

2

⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡−σ=σ ϕ

κ

ρ−κ−

ϕϕ

d

e

where d – the distance between the neighbouring antennae of the grid; 2

κϕσ , 2

mϕσ – the dispersions of the oscillation phases difference in “k” and “m” elements of

the antenna system; mK ,κ – the correlation coefficient between EMF amplitudes in “k” and “m” antennae;

mK ,κ′ – the correlation coefficient between EMF phases in “k” and “m” antennae;

ϕρρ1,1

А

– the scales of the space correlation corresponding to the amplitude and phase

fluctuations of the receiving wave;


262

12

2πσ ϕ =2max

.

Then the expression for the interferential grid multiplier in power will be

+π−

+⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛ψ+⎟⎟

⎠

⎞⎜⎜⎝

⎛ψ

π= ∑∑

=κκ

=κκ N4

4sincosN4

F2N

1

2N

12

2

( ) ( )

( ) ( ) ( )

( ) −⎪⎭

⎪⎬

⎫

⎪⎩

⎪⎨

⎧ψ−ψ−

⎟⎟⎟

⎠

⎞

⎜⎜⎜

⎝

⎛+

π−π

×

⎢⎢⎢

⎣

⎡×−σ

π−+

⎥⎥⎥

⎦

⎤

⎢⎢⎢

⎣

⎡−σ+

∑

∑∑

+κ=κ

ρ−−

ρκ−−

ρκ−−

−

=κ

ρ−κ−

ϕ=κ

ρ−κ−

ϕ

ϕϕ

ϕψ

N

1mm

d1mdmdm

1N

1

d1

max2

N

1

d12

max2

cos14

1N2

41N1

2

22

2

22

2A

22

2

22

2

22

eee

ee

( ) ( )

( ) ,.cos142

11 1

2

2212

22

⎥⎥⎥

⎦

⎤

⎪⎭

⎪⎬

⎫

⎪⎩

⎪⎨

⎧

−⎟⎟⎟

⎠

⎞

⎜⎜⎜

⎝

⎛

−⎟⎟⎟

⎠

⎞

⎜⎜⎜

⎝

⎛+

−− ∑ ∑

= =

−−−−N N

mm

dm

A

dm

κκ

ϕρρ

κ

ψψπ

π ee

where ( )ψ−κ=ψκ 1 – the phase shift between EMF of the “k” and the first antennae; ( )ψΔ−ϕ⋅θ⋅λπ=ψ coscos2 d – the regular phase shift between the EMF of the

neighbouring antennae of the antenna system; θ – the angle of the coming received wave in the vertical plane; ϕ − the angle of the coming received wave in the horizontal plane; Δψ – the phase’s difference between the EMF of the neighbouring antennae used for

controlling the diagram direction of the antenna grid. The first member of the given expression will be the interferential multiplier of the antenna

system according in power in case of the absence of the fluctuations of the received wave field. The second and the third members of the expression characterize the parasite growth of the

level of the reception of the signals from the latter directions The fourth member characterizes widening of the main petal of the diagram direction of the

antenna system due to the fluctuation of the oscillations phases in the separate system elements. Taking into consideration the statistic characteristics of the received signal and using the

expression for the average fixed multiplier of the receiving antenna grid in power, we will be able to evaluate the distortions of the diagram direction of the antenna systems in use, or to choose properly its length and number of elements at the stage of designing of the receiving antennae system. References 1. Шелковников В.А. Отражение плоских волн от магнитодиэлектрического слоя, расположенного на

идеально-проводящей поверхности. B кн.: Сборник докладов международного симпозиума "Экология, авиация, техносфера- взгляд в третье тысячелетие", 2-5 декабря 1996 г., Рига. Рига: РАУ, 1996.

2. Моргунов А.Д., Шелковников В.А. Приемная линейная эквидистантная антенная решетка декаметрового диапазона. В кн.: Теория и техника радиолокации, радионавигации и радиосвязи в ГА: Межвуз. сборник научных трудов МГА. Рига, 1980.

3. Моргунов А.Д., Сикержицкий Ю.М., Шелковников В.А. Экспериментальные исследования статистических характеристик сигналов и помех декаметрового диапазона. Рига: РКИИГА, 1981. (Деп. в ВИНИТИ 27.07.81, № 3780-81 Деп.)


263

THE ANALYSIS OF THE RECEIVING ANTENNAE EFFECTIVENESS

Vladimir Shelkovnikov

Transport and Telecommunication Institute

Lomonosov Str. 1, Riga, LV 1019, Latvia Ph: 7100573. E-mail: [email protected]

Numerically effectiveness of receiving antenna is characterized by the threshold sensitivity, the latter means the value of the useful signal electrical field tension near the antenna птE , at which the useful signal voltage caused by the antenna thermal noises at the antenna output in case of outer interference absence.

In case of outer interference existence threshold sensitivity ПE is considered to be the value of the useful signal electrical field tension at which the useful signal voltage is equal to the voltage caused by the thermal noises and outer interference at the antenna output.

The weakly directed electrical antennae are mainly used as receiving antennae in aviation. That is why we should carry on the comparative estimation of the ferrite antennae efficiency through the prism of the aviation antennae.

Let us find the threshold sensitivity of the ferrite antenna taking into account the outer interference. The full power of the ferrite antenna without thermal losses power is equal to

,1121 22

222⎥⎦

⎤⎢⎣

⎡⎟⎠⎞

⎜⎝⎛ +++++== Σ ствствствн EE

BEE

BEEE

BEEAEAP

where A – proportionality coefficient; E – useful signal electrical field tension; вE – the tension of the electrical field of the interference having the wave nature (mainly

atmospheric and mutual interference); стE – tension of the electrical field of the interference having mainly electrical nature (such

interferences include industrial interferences and mutual interferences caused by the re-radiation of the objects near receiving antenna);

B – coefficient showing how many times the EDF of the ferrite antenna caused by the field стE is lower than the EDF of the wave field when the values of стE and E are equal.

The summarized overage power of interferences is equal to

,1121 22

2ном тствствствн PEE

BEE

BEEE

BEAP +⎥⎦

⎤⎢⎣

⎡⎟⎠⎞

⎜⎝⎛ ++++=

where ƒΔ⋅= −17T 104,0P – thermal losses power at the room temperature; ƒΔ – pass band expressed in kHz; 2вE , 2

стE – effective values squares.

Equalizing the useful signal power to the summarized interferences power for the receiving ferrite antenna we will get the useful signal field tension threshold value.


264

.1121 222

2птствствствп EEE

BEE

BEEE

BEE +⎟

⎠⎞

⎜⎝⎛ ++++=

In this expression we did not take into consideration the useful signal re-radiated field influence. E and вE are the uncorrelated values. There can exist the correlation between E and стE as well

as between вE and стE . Taking into consideration the equally probable phases distribution, we will get after making the

values average

.1 222

22птствп EE

BEE ++=

Here the inducers pointing to the effective values are omitted. Similarly we can get the expression for the electrical antenna threshold sensitivity.

.2222птэствпэ EEEE ++=

In this expression B=1, as the electrical antenna reacts similarly to the electrical component of both – the wave and static fields.

The relative efficiency of the electrical and ferrite antennae is determined by the expression

.

1

111

22

22

2

222

222

2

⎟⎟⎠

⎞⎜⎜⎝

⎛+⎟⎟

⎠

⎞⎜⎜⎝

⎛+

⎟⎟⎠

⎞⎜⎜⎝

⎛+⎟⎟

⎠

⎞⎜⎜⎝

⎛+

=++

++=

в

птэ

в

ст

в

пт

в

ст

птэств

птств

пэ

п

EE

EE

EE

EE

BEEE

EEB

E

EE

For the electrical antennae the length of which corresponds to the wavelength in the decametric waves band, the value птэE can be neglected, that is why

.

1

111

2

22

2

22

222

2

⎟⎟⎠

⎞⎜⎜⎝

⎛+

⎟⎟⎠

⎞⎜⎜⎝

⎛+⎟⎟

⎠

⎞⎜⎜⎝

⎛+

=+

++=

в

ст

в

пт

в

ст

ств

птств

пэ

п

EE

EE

EE

BEE

EEB

E

EE

It is known [1,2,3,4], that the value B can reach the meaning 30 dB and more, then in case

2

222

BEEE ст

стпт −<

or approximately 22стпт EE < , the receiving ferrite antenna becomes efficient than the electrical

antenna. If the conditions 1<впт EE are fulfilled, the tuned ferrite antenna will not have less efficiency

than one of the electrical antenna efficiency even in case, when the electrical antenna is placed far from the re-radiating objects, electrical circuits and the other elements creating the interference стE .


265

References [1] Моргунов А.Д., Сикержицкий Ю.М., Шелковников В.А. Методика определения характера

электромагнитного поля полезного сигнала и помех по отношениям значений электрического вектора к магнитному. В кн.: Повышение надежности и дальности авиационной радиосвязи при применении авиации в народном хозяйстве (ПАНХ) и на местных воздушных линиях (МВЛ). Часть 2. Исследование вопросов обеспечения надежности р/связи в диапазоне ДКМВ и на МВ в условиях воздействия нестационарных и взаимных помех: Отчет по НИР ГР 81066148. Рига: РКИИГА, 1981.

[2] Dunlavy J.H. Design Aspects of Ferrite Antennas in the Frequency Range Below 30 MHz: Proc. Electron. Component Conf. Washington, 1968.

[3] Шелковников В.А.. Экспериментальные исследования макетов ферритовых антенн В кн.: Исследование эффективности применения КВ антенн для предприятий связи ГА : Отчет по НИР (промежуточный) ГР 76000324. Рига: РКИИГА, 1975.

[4] Шелковников В.А.. Экспериментальные исследования макетов ферритовых антенн В кн.: Исследование эффективности применения КВ антенн для предприятий связи ГА : Отчет по НИР (заключительный) ГР 76000324. Рига: РКИИГА, 1976.

Transport


267

POSSIBILITY OF PASSENGER INTERMODALITY IN LITHUANIA

Daiva Griskeviciene, Algirdas Griskevicius

Vilnius Gediminas Technical University

Transport Management Department Plytines Str. 27, Vilnius, LT - 2040, Lithuania

Ph: (+370) 5 2744779, Fax: (+370) 5 2745059 1. INTRODUCTION

The passenger intermodality has not yet received the same attention as intermodality in freight transport, which is being promoted with a number of concrete initiatives on a European level. The main aim of intermodality is to provide the passenger with a seamless door-to-door journey, which is efficient and comfortable. For the individual passenger the intermodality is a route consisting of a combined chain from origin to destination involving at least two different modes, excluding walk for passengers.

On another hand, the intermodality is not a route of a single passenger only, but also a concept and planning principle of co-operation and organisation of several modes of transport. Preconditions for true intermodality are connected with the terms of interconnection and interoperability. Intermodal transport can constitute complex trip chains, which create high demands on the interfaces and operational integration of the transport system.

Implementation of intermodal passenger transport chains is an efficient and more sustainable alternative to car transport. However, there is no comparable work programme for intermodal passenger transport as there is regulative and financial incentive action for freight transport.

The research on intermodal passenger transport at the European level has remained at the level of policy, research programmes and relatively uncoordinated standardisation activities mainly in the area of transport telematics. The aim of the Lithuanian study is to create the basis for policy implementation and work programme in the country. It will assist and but will also cover issues of regulations, financing programmes, European co-ordination and standardisation. 2. ANALYSIS OF PASSENGER SERVICE MARKET

In Lithuania passengers are transported by the public regular scheduled transport: by road,

railway, air and water transport modes; also passengers travel by cars: own and/or official. Public regular scheduled transport is quite popular among population (Table 1).

During Soviet times the public regular scheduled transport has been very well developed according to then existing lifestyle and population demands. Then it fully met the dislocation of productive force and population demands in terms of domesticity, culture and leisure travels. Much attention was paid not only to urban transport but also to the transport within the entire country, as well as to that connecting with other Soviet republics.

After restoration of Independence it became clear that the inherited transport system was inadequate to meet the altered transport demands of population. Whereas the economic reform had continued for a whole decade the passengers’ demands for transport were also gradually changing. However from the very beginning of reformation the regular scheduled transport has undergone economic losses caused by confusion of travel demands and insolvency of population, especially in the long-distance and international transport. In the beginning of the Independency period the flows of national and urban passengers decreased, the same as those of incoming tourists and Lithuanians travelling abroad. Constantly, through the entire decade, decreasing passenger flows in the public transport still keep the tendency to recede. This proves that the socio-economic level of population has not reached an adequate level, and that regrouping/shifting of passenger transportation modes is still going on.


268

Table 1. Passenger transportation by Public Transport in Lithuania

1996 1997 1998 1999 2000 2001 2002

Total passengers, thous. 609414,2 551378,8 516242,7 471929,5 383243,0 355874,4 358324,8 Rail transport 14189,6 12556,6 12194,6 11527,3 8852,1 7718,1 7217,2 Road transport 593474,6 537079,7 502138,8 458327,6 372684,2 346400,8 347782,7 buses 361648,0 346834,3 316157,7 273492,4 213349,9 182099,4 182117,7 trolleybuses 231826,6 190245,4 185981,1 184835,2 159334,3 164301,4 165665,0 Water transport 1510,8 1471,3 1607,3 1779,1 1364,1 1392,4 2948,6 sea 40,8 36,4 43,7 50,8 64,2 68,8 58,4 inland waterways 1470,0 1434,9 1563,6 1728,3 1299,9 1323,6 2890,2 Air transport 239,2 271,2 302,0 295,5 342,6 363,1 376,3 National transport 605931,6 547861,5 513090,2 469108,0 380404,3 353048,3 355462,7 Rail transport 12159,8 10611,5 10536,4 10044,2 7411,6 6314,0 5755,4 Road transport 592300,0 535813,7 500989,0 457334,3 371691,7 345410,2 346815,7 by buses 360473,4 345568,3 315007,9 272499,1 212357,4 181108,8 181150,7 by trolleybuses 231826,6 190245,4 185981,1 184835,2 159334,3 164301,4 165665,0 Inland waterways transport 1470,0 1434,9 1563,6 1728,3 1299,9 1323,6 2890,2 Air transport 1,8 1,4 1,2 1,2 1,1 0,5 1,4 International transport 3482,6 3517,3 3152,5 2821,5 2838,7 2826,2 2862,0 Rail transport 2029,8 1945,1 1658,2 1483,1 1440,5 1404,1 1461,8

Road transport (buses)

1174,6

1266,0 1149,8 993,3 992,5 990,6 967,0 Sea transport 40,8 36,4 43,7 50,8 64,2 68,8 58,4 Air transport 237,4 269,8 300,8 294,3 341,5 362,7 374,8

6094

14,2

5513

78,8

5162

42,7

4719

29,5

3832

43

3558

74,4

3583

24,8

6059

31,6

5478

61,5

5130

90,2

4691

08

3804

04,3

3530

48,3

3554

62,7

3482

,6

3517

,3

3152

,5

2821

,5

2838

,7

2826

,2

2862

0100000200000300000400000500000600000700000

1996 1997 1998 1999 2000 2001 2002

International transport

National transport

Total passengers, thous.

Passenger transportation by Public Transport in Lithuania

Chart 1. Passenger transportation by Public transport in Lithuania

A share of the passenger market in long-distance communication has been taken over from the

public transportation by the automobile transport over the last decade. The number of automobiles registered in Lithuania doubled during the last 10 years. The automotive level in 2002 reached 340 per 1000 residents, whilst it was 145 automobiles per 1000 residents in 1990. The automotive level is increasing due to the expansion of sales in the new and the widely spread western make “second hand” automobiles.

The fallen positions of the public transport, even more induce the use of automobiles. After the economic reform an increasing share of private automobiles is used for trips to work and for work


269

purposes. Non-correspondence of the public commuter transport network and traffic schedules to the passengers’ changed demands impels residents to acquire private cars and use them more often. It is expected that the public transport should offer more attractive routes and a traffic schedule in demand.

An overmuch increased intensiveness of the automobile transport is noticeable in intercity communication, especially during the summer time, what comes close to the limit of the main highway capacities. Due to this reason the railway and bus transport will be used more often for long-distance national trips. The share of the passenger market reverted to the railway and bus transport will depend on the quality and attractiveness of the public transport.

Level of automobilization in Lithuania

316304

315291

260235

208

150170190210230250270290310330

1996 1997 1998 1999 2000 2001 2002

Personal passenger cars per 1000 inhabitans

Table 2. Number of road vehicles

1996 1997 1998 1999 2000 2001 2002

Passenger transport Passenger cars 785088 882101 980910 1089334 1172394 1133477 1180945 of which personal 745742 835462 920373 1021795 1097797 1055164 1093882 Personal passenger cars per 1000 inhabitants 208 235 260 291 315 304 316 Buses 15482 14888 15156 15590 15069 15171 15376 Trolleybuses 544 547 523 500 474 470 466 Motorcycles 19402 19128 19266 19515 19842 20244 21017

The growth of the automotive level in Lithuania is fostered by an improved standard of living. If

the greatest boom of the automotive level took place in cities, the number of cars is expected to increase in rural areas and small settlements due to the growth of work places and re-deployment of labour resources in peripheral areas. It is forecasted that the transport mobility will increase in the entire territory of Lithuania, and, at the same time, the demand for travel by public transport will increase. The need for travel by the railway transport is expected to increase in those regions and cities, which have a good access to the railway lines/stations: bus schedule is coordinated with the train traffic schedule, there is a sufficient infrastructure and parking lots for cars, motorcycle and cycle transport at passenger stations.

Although 88,5 % of the registered road transport vehicles consists of cars, only part of them, however, is used during a weekday or traffic jams. The renovated and upgraded bus stocks propose more flexible services for passengers in long-distance routes. Because of a speedier implementation of investments, the bus transport attracts a share of passengers on intercity routes. It is probable that the railway transport will offer cheaper, however qualitative and modern services in the future, at the same time conquering back the lost share of passengers during the reform. Renovation and upgrading of the suburban train stock will provide more opportunities to increase passenger transportation on local routes.

One of the reasons for an increasing market share of the private car across most of European countries is its ability to provide (nearly) door-to-door transport – despite the problems with congestion and parking in many urban regions. A lack of interoperability for intermodal transport systems is among the reasons for congestion in Europe.


270

Passenger transport in 2002

Passenger cars; 1180945

Buses; 15376

Motocycles; 21017

Trolleybuses; 466

of which personal; 1093882

other passenger cars; 87063

Chart 2. Structure of the passenger transport park in Lithuania

An analysis of the passenger service market and today situation of passenger long-distance

travel in Lithuania shows that the main weakness is as follows – an absence of the organized passenger intermodality in the country. The strengths – county’s favourable geographic position, needs of the international trips, good conditions of road, air and water transport infrastructure – stimulate to improve the quality of passenger conveyance and to organize the intermodal service network. There are some opportunities to develop the system.

Due to the not vast territory and its compactness two main objectives of long-distance passenger transport may be noticed in Lithuania: interurban (intercity) and international (cross-border). In the international transport prevail: mainly air, railway, bus transport and some maritime and car transport. In the interurban transport inside the country prevail: regular route scheduled bus and railway transport, and car transport. 3. STRATEGY OF LITHUANIAN TRANSPORT SECTOR

Total productive force restructuring followed by the gradual regrouping of work places and their new dislocation, change of residence places of a certain part of inhabitants, alteration of the mental model and occurrence of new interests, growing economic potentials of demand satisfaction – all this directly has influenced and continues to impact the population and the passenger market. As the result of the economic development during the thirteen years of independence two main facts may be noted – the leap of auto mobilisation level in the whole country especially in towns and the decrease of demand in public transport services caused by the inadequacy of supply to the altered requirements of demand.

In this situation efforts were made to create a new national transport strategy. In 2004 was finalised the elaboration of the Strategy of Lithuanian transport sector development until 2025 prepared by the Ministry of Transport and Communications of the Republic of Lithuania. The intermodality concept of passenger transport is already included there as one of its objectives. It has been presented in the form of concrete measures for the medium-term (until 2013) and long-term (until 2028) perspective periods. The integration of external and internal passenger transport services has been foreseen by linking external passenger transport terminals (air, maritime, river ports and railway stations) with the internal/local transport system thus enabling good accessibility in towns and settlements. It is foreseen to make pedestrian and bicycle paths in the suburbs of towns and settlements, to integrate them into the general transport system by installing parking sites at the terminal bus stops of the public transport. It is foreseen to co-ordinate the use of cars with the work of the regular scheduled public transport, to limit and restrict/prohibit the car traffic in the old-town and central areas of cities and in the densely inhabited district centres where it is purposeful to set the zones of pedestrian and motor-less traffic. 4. OPPORTUNITY TO IMPLEMENT THE INTERMODAL PASSENGER

TRANSPORTATION

Intermodal passenger transport ranges from small-scale “bike & ride” schemes to international trips combining air, rail or private car transport. To improve the opportunities for sustainable intermodality, a systematic and high quality approach to transport is needed. Sustainable transport will


271

be the guiding principle, that environmental, social and economic sustainability issues define priorities and that mode combinations will receive most attention.

The effort to improve intermodality involves many issues ranging from framework conditions, to concrete services and implementation issues.

Legal framework. The basic framework of the legal acts is created. However there are no legal acts regulating combined and intermodal passenger transport, its co-ordination and control. Although there are no artificial barriers for passenger transport intermodality, there are not yet created conditions for arranging such type of transport. There is lack of legal basis for operators of different origin for their work in the single market. Therefore there were difficulties in passenger transport market based co-operation of activities between the small size private buses and the state owned bus fleet/park that lost its former status.

Economic assumptions. Some modal conflicts exist because of the different economical interests of different operators. The changers of commercial and technological requirements due to the integration to the EU and development of the market and demand constrain the public transport operators to accommodate to new circumstances. But this is own separate adaptation of these companies to the new situation in the market.

The changers of the demand are going to the development of passenger market. Social-economic possibilities of population are increasing every year. But financial potential of population is arising slowly, so demand for trip of international passenger transport is lower than in other countries. The best opportunity to implement the intermodal passenger transportation is the organization good interface with EU level passenger transport network, integration into the international passenger service market.

International co-operation. Until now yet there are no intergovernmental agreements on the development of intermodal transport, however Lithuania participates in the Baltic Sea Region Countries’ Programmes in the fields of the road network development, traffic safety enhancement and short sea shipping development.

Service combination. Certain elements of co-ordination of separate transport modes have been formed in Lithuania, but they are not included into the general system. It is, for example, the combination of car approach facilities to the Vilnius airport with the short-term and long-term parking facilities.

Because of the space shortage there is no possibility to equip bigger car parking close to most external transport terminals (air and railway). Compactly inhabited territories located near the passenger railway stations’ terminals were not reserved for car parking because in the initial period of their design the auto mobilisation level was low thus the related forecasts were also low.

Presently there are foreseen to be started low budget flights from Kaunas airport; they would attract many clients and, on the other hand, would require special equipment for parking of cars coming from other towns and from Kaunas as well. Similar development is possible also in Palanga airport.

In any case the public urban transport systems are traditionally interrelated with the external/outgoing transport terminals and they serve them through the whole working day according to the seasonal changes. This problem has been solved in smaller cities as well; there buses that service the district go on the schedule/timetable co-ordinated with the arrival of trains into the stations of these cities.

Well-balanced and sustainable urban and external transport services in the country are looked upon as a long-term target being constantly aimed at and corrected according to the changing situation in the market of passenger transport services supply.

Integration and interoperability. Conveying of the external transport priority to the international passenger transportation has to be harmonised with the neighbouring countries. Lithuania has experience from the I Trans-European Railway Corridor project protection and defining of its route (places of border-crossing with neighbouring countries) and from priority attachment to the project, its long discussing and time-consuming co-ordination with the Republics of Latvia and Poland. High-speed passenger traffic – it is also foreseen to be implemented in this European gauge railway ‘Via Baltica’ line that is now fixed in the international agreements. Furthermore, in this project there is proposed an additional high-speed railway track from Kaunas to Vilnius as the most important and well founded by possible flows high-speed line. In terms of intermodality the traffic of this project will have to be fully integrated and co-ordinated with the national level transport system.

The interoperability of inland transport networks lacks a developed railway route system (the railway network is underdeveloped) to which regular scheduled route bus system could correspond, as


272

at present its interrelation with railways is not sufficient. The development of networks can be implemented only on the basis of scientific research. As far as now there are no concrete calculations and no modelling of combined passenger transport operation inside the country (local) and in cross-border/international transport.

In the railway transport for passenger transportation the passenger trains are destined, which goes by an average speed with numerous stops, also there are international high-speed trains, which stop only in large towns. Whereas the territory of Lithuania is not vast and the railway network is not dense the inhabitants of Lithuania as far as now do not have to change transport modes during their trips.

However the analysis of international transport requires co-ordination of separate transport modes for the passengers that are living in remote areas from the international railway stations. In major towns the railway stations are easily accessible by the street network of urban transport by buses (trolley-buses), taxis and cars.

In similar way the stations of outgoing buses can be reached. However in small towns where the public traffic is not frequent, and in rural type settlements, the problems of railway or bus station accessibility may occur.

Traditionally the bus fleets/parks of small cities and districts used to plan their regular scheduled routes by harmonising them with the passenger transport traffic: when the train arrived to the station the scheduled regular bus was already awaiting, as it had had brought passengers into the railway station thus afterwards taking in turn passengers that came by railway. This principle had been maintained until now in locations where the correspondence of scheduled bus routes with the railway traffic remained. For local people such co-ordination is well known and they make use of it.

The international regular scheduled routs of all international bus carriers are published in the yearly journal/magazine issued by the State Road Transport Inspectorate. In the Internet this information does not exist. The fleets/parks of long-distance buses also do not publish all their timetables in the Internet, the same as all haulers. For this they have their own commercial argumentation.

Besides the regular scheduled haulage the bus fleets/parks perform charter operations too. Although not all charter haulages can be profitable. The presence of illegal haulers in the market used to cut haulage prices, therefore a certain number (not high) of companies suffered losses (in the year 2000 out of 38 companies 5 ones suffered losses).

Information system. Advance informing of population on the provided transport services, concrete travelling possibilities, as well as informing passengers in terminals and during the travelling time improves every year due to the implementation of marketing means, modern technologies and better organisation of works.

Regretfully, all information related to transport services in Lithuania is available only according to different transport modes. Therefore it is difficult for people to orient about the possible time duration of travels in the case of different transport modes combination/interchanges.

On the other hand, even our local people will not be able to define from the information provided a possible combination of transport modes if an element of local transport of other town or district/periphery is included into the chain of combined transport.

Superficial Internet information is available on the sights of enterprises. As a rule the sights are reluctantly changed, seldom renewed. Therefore even published timetables are not very reliable to Internet browsers. Everybody in Lithuania that the most precise information may be obtained only in the stations knows it.

Ticketing system. The ticketing system in the public transport does not meet the requirements of the present time. It lacks versatility, innovation, modern ticketing variety, and introduction of electronic ticketing in urban and local transport. The entire public transport needs a clear structure and information. It is considered that public urban transport lacks uniform tickets. Lithuania needs to have real-time traffic timetable information, possibilities of booking by Internet, electronic accountancy.

In the urban transport tickets in most cases are not integrated. Long-distance transportation companies also have their own tickets. National level united information centre is mostly necessary. It is necessary to create a site where information on carriers and their services could be accumulated and displayed.

It is still early to speak about a one-ticket concept because the question of profit distribution is not clear. Besides, there are no guarantees for a carrier that he will regain his profit from the institution that has sold the ticket. For haulers it is easier to agree with agencies: if in several months’ time the carrier does not regain his profit, the agreement is cancelled. Thus, according to the opinion of carriers there is a commercial risk in the attachment to one institution selling tickets for all routs.


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Beside the main services the travel agencies find and coordinate other long-distance links abroad coordinating them to the timetable of plain arrival in the destination airport and book tickets, for example, for any long-distance railway/bus journey. Therefore people are happy to communicate with the travel agencies and book their tickets there.

Other travel agencies represent only a certain transport carrier, therefore they book/reserve tickets exceptionally to the services of that particular carrier. Such are agencies representing Lithuanian and foreign airlines, maritime ferries, inland waterway ferries, railways, long-distance transportation and tourist bus enterprises. Regarding the tide and ebb of passenger flows they advertise and take part in public events in the role of sponsors

Data collection. Data of the intermodal passenger transport are not collected, as there does not exist the traffic of such kind in Lithuania. Each participating company would collect when such traffic occurs the data of such kind. But there does not exist and there is not yet foreseen any institutional distribution and there is no nomination of such institution responsible for the arranging of such kind traffic. Great difficulties are caused by data collection of any passenger transportation kind, definition and composition of their reliability. Accessibility of data, especially of the economic-financial causes difficulties in elaboration of studies and limits the depth of analysis. CONCLUSIONS

1. The investigation of different modes of passenger transport shows the possibilities for the cooperation in the integrated service market.

2. There is no functioning mechanism in Lithuania able to co-ordinate transportation services according to the origin of capital and perform co-ordination of route lines in long-distance transport For the preparation of regular scheduled routes for combined passenger transport in Lithuania it is necessary to start with the elaboration of the general concept, formation of the legal basis, realisation of strategic tasks, as well as designing and implementation of concrete pilot projects.

3. Lithuanian transport strategy already for quite a long time states that it is necessary to join the common continental information systems on transport traffic and ticketing so that people could choose travel combination and book tickets in advance on their own. This is now very important because the numbers of personal computers and Internet users are rapidly increasing. This is particularly important in major towns the inhabitants of which are more mobile in transport terms.

4. The State being responsible for public transportation has to take care of organising the public transport. Through the local municipalities the local, suburban and intercity transport formation, co-ordination and financing functions are performed. The State has to keep its obligations: to arrange public transport services, arrange agreements with operators, compensate loss-making routes of public transport, subsidise and guarantee State owned capital enterprises the vehicle fleet of which needs to be renewed.

5. For operator coordination of large numbers of passenger transportation services a new structure is necessary, which would be able to perform similar functions and form long-distance passenger transportation service market on the national and international levels. The lack of such institution is the foremost barrier for the development of passenger transport intermodality.

6. Finally, a better-organised transport system contributes to the main Community objectives competitiveness, employment, sustainable development and territorial cohesion. References [1] Butkevicius J. Passengers’ conveyance: Monograph. Vilnius: Technika, 2002., 416 p. [2] Griskeviciene D., Griskevicius A. Public transport passenger’s social problems and their solution. In:

Transport: Technologies, economics, environment, health: Collective monograph. Vilnius: Technika, 2003, pp.623-685.

[3] Burinskiene M., Paliulis G. Urban transport problems and their solutions. In: Transport: Technologies, economics, environment, health: Collective monograph. Vilnius: Technika, 2003, pp. 559-622.

[4] Griskeviciene D., Valeika V., Juskevicius P. Transport. The Territorial Master Plan of Lithuanian Republic. Vilnius: Urbanistika, 2001.


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DEVELOPMENT OF PASSENGER TRANSPORTATION BY LITHUANIAN SEA TRANSPORT

J. Butkevičius 1, A. Vyskupaitis 2


Dept of Transport Management Plytinės Str.27, LT-10105 Vilnius, Lithuania

1 E-mail: [email protected] 2 E-mail: [email protected]

1. INTRODUCTION

Following restoration of independence of Lithuania, passenger transportation by ferries from Klaipėda ports has been progressing rapidly – a number of ferry lines are increasing, flows of passengers are growing. Possibilities of ferry navigation, however, are not fully exhausted. Therefore, this article deals with analysis of passenger transportation by Lithuanian sea transport and trends of development of this transportation. 2. DEVELOPMENT OF TRANSPORTATION BY FERRY LINES

IN THE BALTIC SEA

The market of transportation by ferries is one of the most perspective and the most rapidly developing markets in the international shipping. The world ferry fleet has already about 2800 ships, 1200 of which are cargo-passenger ferries of different purpose and 1600 ones are high-speed ships. The Baltic region, in which a number of population amounts to 85 mill., includes 500 ports.

Transportation by ferries within the Baltic Sea in the international market is the most concentrated in the world. Prevalence of short and medium routes determines frequent ship traffic. The total number of ferry lines in the whole Baltic region is constantly growing. A fair amount of this number includes inner lines, connecting parts of the Baltic state continents with island territories.

Ferries have become an inseparable sea chain among overland routes in most countries. This factor is effective in the Baltic Sea as well, where ferry lines are connected with European continent through a thousand of islands – in the Baltic channel zone, Goth land, Born Holm, Aland, Saarem, etc. However, the major stimulus in the Baltic ferry transportation market happens to be relations of the Scandinavian Peninsula and Finland with the other European part.

The Baltic ferry transportation market (based on data of the year 2001) makes up 161,5 mill. passengers, 54 mill. cars, 4,7 mill. trackers, 258 thou. buses. Internationally, each of these complex trade parts plays a significant role in ferry transportation. The Baltic Sea region covers 43 % of the world car transportation, 30 % – bus transportation, 23 % – cargo trackers, 20 % – passenger transportation. In the major ferry lines cargo transportation exceeds 40 mill. tons per year.

Development of passenger transportation has been the fastest – on the average, its number has increased by 6 % in the latest years. Growth of car transportation is slightly lagging behind - by 4,5-5,0 %. The greatest number of ferry passengers is transported between Denmark and Sweden – 24,0 mill., between Finland and Sweden – 8,8 mill., between Denmark and Germany – 7,8 mill., between Finland and Estonia – 6,0 mill., between Germany and Sweden – 2,4 mill., between Poland and Sweden – 0,78 mill. passengers per year (based on data of the year 2001).

On the average, each Baltic ferry line has two ferries, however, in the specific ferry line service their number may vary from 1 up to 3 – 4. The region fleet contains all types of ferries, the main part of which consists of car transport ferries and passenger ferries, carrying motor transport vehicles as well.

A high-speed ferry, the speed of which exceeds 30 knots or more, successfully competes with air transport in passenger transportation; other types of ships also play an important role in cruise business. Here, the so-called “cruise ferries” should be mentioned – heavy and comfortable ships with high-level service.


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These expensive ships, same as cruise liners, are distinguished for long exploitation. Though in the nineties new ships supplemented the world ferry fleet, currently, ships over 20 year-old make up over 50 % of ships or 40 % of fleet tonnage. Ferries may be in service 2-3 times longer than freighters, they are being modernized, transferred “from hand to hand”, and renamed.

Ferry fleet has avoided the mass „wastage“ into the famed registers. Baltic ferries, often arriving into national ports, are usually registered with its own country’s flag; however, sometimes flags of free economic zones may be still met.

The united navigation politics and the common sea servicing market in the EC have been purposively formed for many years. Integrated processes provide for harmonization of competitive terms within the EC, mutual access to coasting transportation (mutual permit for coasting transportation), unification of national sea laws, and a number of other projects. The idea of the united shipping register – „EUROS“, has been considered for many years; this would enable to move to the common „euro – flag“ in all sea ships of countries-members. The EC general action program may make a great effect on the Baltic transportation market.

Presently, some leaders in the market have a control over the major ferry centre in the Baltic waters. In the Western basin part interests of the Danish-German Scandlines and the big group Stena Line in the eastern Baltic part there dominate, and in the eastern Baltic part other two competitors fight for the market – the Finnish Silja Line (together with a subsidiary Sea Wind) and the Swedish Viking Line. Scandlines ferries carried about 20 mill. Passengers per year, Stena Line – 18,5 mill., Viking Line – 5,4 mill. and Silja Line – 4,8 mill.

Transportation by ferries brings income of three types: from passenger transportation, from car transportation and from trade and services, rendered in ferry shops, restaurants, etc. 3. ANALYSIS OF PASSENGER TRANSPORTATION

BY LITHUANIAN SEA TRANSPORT 3.1. Ferry Lines

Ferries from Klaipėda go to Kiel, Mukran (Germany), Aarhus (till April of 2002), Copenhagen, Fredericija, Aabenraa (Denmark), Karlshamn (Sweden) (from April of 2002).

The ferry line Klaipėda – Mukran (Germany) was opened in 1987. This line transports passengers, motor vehicles and also railway wagons. On 13 February 1998, the Danish ferry „Belard“ moored in Klaipėda international sea crossing; it used to run from Klaipėda to the Danish town Aabenraa and back twice a week. It could carry 50 motor vans and 24 passengers. This ferry line was opened on Danish businessmen’s initiative. This is related with ever strengthening political and economical relations between Lithuania and Denmark. Presently, „Scandlines“ AG ferry „Sea Corona“, capable of carrying 12 passengers, runs by this line.

The ferry line Klaipėda – Kiel was opened in 1989. Currently, 3 cargo-passenger ferries, „Šiauliai“, „Palanga“ and „Svealand“, run by this line.

The ferry line Klaipėda – Aarhus was opened in 1993. The ferry „Šiauliai“ was running by it. This line was closed in April of 2002. Instead of this line, on 19 April 2002, the line Klaipėda – Karlshamn was opened. The cargo-passenger ferries „Kaunas“ and „Šiauliai“ run by this line.

The ferry-line Klaipėda – Stockholm was opened on 10 June 1997. The cargo-passenger ferry „Palanga“ was running by this line.

Presently, ferries from Klaipėda port transport passengers, motor trailers, railway wagons, cargo trucks and cars to Germany, Denmark and Sweden.

For servicing ferry lines Ro-Ro type ships are used. The distinguishing feature of these ships is as follows: self-propelled vehicles (cars, trucks, etc.) enter and leave the ship on their own. If only ferries carry semi trailers, without trackers, they are tracked into and out of ferries. For passenger transportation cabins are installed in ferries. A number of cabins depend upon a size of a ferry and a nature of services to be rendered. For instance, in case the navigation company is intended for servicing short distance routes and is oriented towards passenger transportation, it will exploit high-speed type ferries (catamarans, ships on air-cushions). Traveling by this route is usually not long lasting, therefore, instead of individual cabins, one big hall, accommodating several hundred people, is installed.


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Ferries, servicing the state Klaipėda seaport, are more oriented towards cargo transportation and are not so speedy as passenger ferries; furthermore, traveling usually lasts for more than 8 hours, therefore rest cabins for ferry-drivers and passengers are necessary. 3.2. Analysis of Flows of Passengers

Flows of passengers transported by ferry lines are covered under the Table 1. Table 1. Dynamics of the number of passengers transported by different ferry lines

in the period 1998-2002 Passengers transported

Ferry line 1998 1999 2000 2001 2002 1998 and 2002, compared in %

Klaipėda – Mukran 23 526 18 716 27 620 10 919 9 698 41,2 Klaipėda – Kiel 22 739 29 659 50 959 66 016 64 067 281,7 Klaipėda – Karlshamn (until April of 2002 – Aarhus) 2 268 3 077 3 612 20 218 29 742 1311,4

Klaipėda – Aabenraa 418 1256 1724 1892 1951 466,7 Klaipėda – Stockholm 14 564 17 432 19 971 590 0 0 Total 63 517 70 140 103 886 101 177 107 202 168,8

As the data covered under the Table 1 show, individual ferry lines transport different flows of

passengers. The largest number of passengers – even 59,8 % - was transported in 2002 by the ferry line Klaipėda – Kiel. Flows of passengers transported by this line increased even by 281,7 % within the period 1998 – 2002.

Flows of passengers towards Aarhus were not intense – in 1998 – 2 268 pass., in 2000 – 3 612 pass. After this line had been closed and the line towards Karlhamn had been opened, the flows considerably increased and in 2002 made up 29 742 pass., i.e. even by 131,4 % more than in 1998 towards Aarhus.

Flows of passengers towards Mukran decreased – in 1998, 23 526 pass. were carried in this direction, and in 2002 – only 9 698 pass., i.e. this number reached 41,2 % of the 1998 year level.

Flows of passengers towards Aabenraa are not high, however, they are constantly increasing – in 1998, 418 passengers were transported, in 2002 – 1 951 pass., i.e. the number of passengers increased by 466,7 %.

The total number of passengers transported by all lines per the period 1998 – 2002 considerably grew up from 63 517 up to 107 202 pass., i.e. by 168,8 %. Table 2. Dynamics of loading and landing of road vehicles in Klaipėda state seaport

Year 1995 1997 1998 1999 2000

Road vehicles, loaded, pcs. 32 514 55 332 45 877 37 332 46 107 Cargo vehicles 1 211 1 544 1 696 1 745 1 505 Trailers and semi trailers 17 157 38 314 28 296 18 675 21 992 Trackers with semi trailers 10 581 11 483 10 929 12 027 17 361 Cars 3 517 3 517 4 481 4 393 4 661 Other road vehicles 48 474 475 492 588 Road vehicles, landed, pcs. 6 908 103 986 87 260 52 314 60 174 Cargo vehicles 2 374 3 503 3 739 2 895 3 338 Trailers and semi trailers 17 248 38 821 28 046 19 632 22 006 Trackers with semi trailers 11 457 12 808 11 404 12 194 18 764 Cars 37 860 47 757 42 812 16 738 14 901 Other road vehicles 114 1 097 1 259 855 1 165

In 2001, statistic data processing was modified. The number of wagons, road vehicles and cargo

vehicles transported in 2002 is covered under the Table 3.


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Table 3. Number of wagons, road vehicles and cargo vehicles transported by ferry lines in 2002 Road vehicles transported

Ferry line Wagons, transported, pcs. Total Cargo vehicles and trailers Klaipėda - Kiel 0 62 284 50 098 Klaipėda – Kopenhaga (Federicija) 0 21 015 18 224 Klaipėda – Karlshamn Klaipėda – Aarhus (until April of 2002)

0 15 558 14 140

Klaipėda – Aabenraa 0 11 530 9 740 Klaipėda – Mukran 4 688 10 047 6521 Total 4 688 120 434 98 723

In 1995, 101 603 road vehicles were transported. In 1997, the number of the road vehicles

transported was the largest – even 159 318. In 2002, 120 434 road vehicles were transported, i.e. by. 18,5% more than in 1995 m. Furthermore, in 2002, 4 688 wagons were transported by the line Klaipėda – Mukran 3.3. Forecast of Extent of Passengers, Transported by Ferries

The forecast of extent of passenger transportation for the period till the year 2015 was performed; The forecast of volumes of passengers, carried by all ferry lines for the period till 2015 (taking into account the time factor).

1998 1999 2000 2001 2002 2015 Fact data Forecast

63 517 70 140 103 886 101 177 107 202 266 795

The regression equation was used for the forecast:

y = 11840.7t + 53662.3, (1)

where t – tendency time factor.

Figure 1. Forecast of volumes of passengers, transported by ferries

As the Figure 1 illustrates, flows of passengers are supposed to grow up to 266 795 passengers till the year 2015, i.e., as compared with the year 2002, the number will grow by 2,6 times.

3.4. Forecast of Extent of Road Vehicles, Transported by Ferries

The forecast of extent of road vehicles, transported by all types of ferries, for the period till the year 2015 was performed (taking into account the time factor).

1995 1997 1998 2002 2015 Fact data Forecast

101 603 159 318 133 127 120 434 140 137

The regression equation was used for the forecast:

266795

103886

107202

65503635170

50000

100000

150000

200000

250000

300000

1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016

Pas

seng

ers

Fact dataForecast


278

y = 377.2692308t + 125913.9231, (2)

where t – tendency time factor.

Figure 2. Forecast of volumes of road vehicles, transported by ferries As the Picture 2 illustrates, volumes of road vehicles, transported by ferries, are supposed to

grow up to 140137 pcs. till the year 2015., i.e., as compared with the year 2002, the number will grow by 1,16 time. 4. TRENDS OF DEVELOPMENT OF PASSENGER TRANSPORTATION

BY SEA FERRIES

According to the forecast, loading of road vehicles into Klaipėda port ferries should grow up by 1,44 time till the year 2015 and should make up 66 797 pcs. per year.

According to the same forecast, landing of road vehicles in Klaipėda port, contrary to loading, should decrease by 1,54 time till the year 2015 and should make up 38 867 pcs. per year. Such forecast of decrease was determined by the fact that a number of cars brought to the port is constantly decreasing – in 1997, 47 757 cars were brought, and in 2000 m. – this number amounted only to 14 901 pcs., i.e. the number of cars brought during this period decreased even by 3,2 times.

While developing transportation by ferries from Klaipėda, a perspective line towards Swedish port Oxelösund should be born in mind. In the latter port a new cargo pier should be installed, branch railing should be tracked – for this purpose a support form the European Community could be expected. Construction works could be performed per year.

Costs would be compensated, if a ferry sailed with a load of 20 railway wagons and 30 trailers twice per week. If the ferry line load made up more than 50 %, the line would be cost-effective. This ferry line would be analogous to the Klaipėda-Mukran line, but they would not compete with each other.

Other perspective ferry line from Klaipėda goes towards the southern Swedish port Karlskron. Currently, thousands of passengers from Lithuania, especially in summer time, use the ferry line Gdynė (Poland)-Karlskrona. In this line the company STENA LINE in 2001 launched the second ferry and built a new passenger terminal. One ferry, belonging to this company, transports about 130 thou. passengers by this line per year; according to the company’s plans, the second ferry from the new terminal should service the analogous flow of passengers. It should be noted that even 80 % of passengers from Sweden come to Poland to do the shopping – thus, Klaipėda and Lithuania could seem attractive to them. In this ferry line a constant flow of Lithuanian car drivers could be expected, as in this case they should not have to cross Poland even until Gdynė, and from Karlskrona they would reach all the southern Sweden, could go further towards Stockholm (the line Klaipėda-Stockholm was closed in 2001), and also to Denmark (after the bridge between Stockholm and Copenhagen in Denmark was built, it is convenient) or towards to Norway.

The perspective ferry lines are also towards Rotterdam in Holland and towards Bremerhafen or Hamburg in Germany.

Presently, a ferry shipping line from Klaipėda towards Swinoujscie (close to Szczecin, Poland) is planned to be opened – for this purpose an operator is being looked for.

When establishing new shipping lines, it is essential to foresee which passenger groups are planned to be serviced and what kind of cargo will be transported, as the total flow of cargo between

101 603

159 318133 127 140 137

120 434

020 00040 00060 00080 000

100 000120 000140 000160 000180 000

1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Pas

seng

ers

Fact dataForecast


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the East and the West undergoes slight changes and these changes are mostly effected by various prohibitions or their suspension.

New navigation lines from the specific Baltic sea eastern port always effect other shipping lines, a part of the cargo flow in that port moves from one line into the other one, when owners of the cargo in new lines acquire temporary privileges and reservation places in future.

When forming flows of passengers in ferry liens, the essential issue is cooperation with tourist companies. For instance, the company STENA LINE, to attract flows of passengers in the line Gdynė-Karlskrona, started contacting with about 350 traveling agencies in Poland.

Another important issue is differentiation of tickets for both individual passenger groups and road vehicles, and also different ticket packages.

The most perspective ferries from Klaipėda are high-speed ferries (when duration of traveling does not exceed 8 hours), transporting road vehicles as well.

One more significant issue, when forming flows of cargo, passengers and road vehicles by ferry lines through Klaipėda port, is attraction of transit flows from Russia, Belarus, Ukraine and other countries. For this purpose, specific marketing programs should be established and later, by means of logistics centre, implemented. 5. CONCLUSIONS

The market of transportation by ferries is one of the most perspective and the most developing markets in international navigation. Transportation by ferries within the Baltic Sea in the international market is the most intensive in the world. This is determined by not only a high number of ferry lines – about 80, but also a high number of ferry journeys that is constantly increasing.

43 % of the world car transportation, 30 % bus transportation, 23 % cargo trackers and 20% passenger transportation are concentrated in the Baltic Sea. In the major ferry lines cargo transportation exceeds 40 mill. tons per year.

Within the Baltic Sea region the united navigation politics and the common sea EC servicing market has been formed for many years. Integrating processes provide harmonization of competitive terms within the EC, development of coastwise transportation, etc.

Transportation by ferries yields three types of income – from passenger transportation, from vehicle transportation and trade („duty-free“) and passenger services. Most Baltic States, since the moment of entering the European Community, are striving for letting navigation companies to preserve duty-free trade in ferries for more 6,5 years.

Klaipėda is a perspective port for new ferry lines. The research shows that the most perspective new ferry lines link Klaipėda with Swedish ports of Oxelösund and Norlskrona, the Dutch port of Rotterdam, German ports of Bremerhaven or Hamburg and Polish port of Swinoujscie (close to Szczecin). References [1] Butkevičius J. Keleivių vežimai: Monografija. Vilnius: Technika, 2002. [2] Butkevičius J. Fundamental Direction of Development and Integration into European Transport

Network.Lithuanian Passenger Systems. In: Nordic-Baltic Transport Research Conference. Riga, 2000, p. 4. [3] Smailys V. Lietuvos jūrų transporto plėtotės perspektyvos ir aplinkosaugos problemos. In: Lietuvos mokslas.

Transportas. Vilnius: Lietuvos mokslas, 1999, pp. 354-412. [4] Szwankowski S. Transport Aspects of Sustainable Development of the Port of Gdansk, Bulletin of the

Maritime Institute in Gdansk, Vol. XXVII, No 1, 2000. p.24. (Instytut morski w Gdansku). [5] Kryžanowski M. The Logistics Centres Adapted to the Demands of the European Case, Bulletin of the

Maritime Institute in Gdansk, Vol. XXVI, No 2, 1999, pp.15-28. (Institut morski w Gdansku). [6] V. Paulauskas. New Shipping Policy and Ports, Jūra ir aplinka, No 1 (5), 2001, pp.7-10. (Klaipėdos

universitetas). [7] Литвинова Н. Роль финансового менеджмента в оценке конкурентно-способности морского

торгового порта. В кн.: Транспортная политика, экономика и образование. Санкт-Петербург: Министерство транспорта Российской Федерации, 2000, с. 138-139.


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END-OF-LIFE VEHICLES AND TRANSPORT EXPLOITATION MATERIALS DEVELOPMENT PERSPECTIVES IN LITHUANIA

A. Pikūnas, V. Valiūnas


Department of Automobile Transport J. Basanaviciaus Str. 28, LT-03224 Vilnius-09, Lithuania

Ph.: +370 5 274 47 90, Fax.: +370 5 274 50 68, E-mail: [email protected] 1. INTRODUCTION

When Lithuania expressed its wish to join the European Union, the necessity of harmonization Lithuanian and EU environmental protection priorities and standards appeared. On 27 June 2001, Lithuania and EU concluded a bargain on the Environmental section. It was one of the most complicated spheres in the negotiations on the membership, first of all, because of its large scale, an abundance of problematic issues and high implementation expenses. It was agreed on the principles that should be implemented at present.

The requirements according to the EU norms are set forth in the relevant Directives. In the present paper, a brief review of the perspectives of Lithuania in exploitation of end-of-life vehicles in conformity with EU Directives that are urgent for the transport sector is provided. The condition of the end-of-life vehicles in Lithuania today and in the nearest future is compared. The principal scheme for control and systematisation of the whole process of treatment of end-of-life vehicles is proposed. 2. THE ANALYSIS OF EUROPEAN UNION DIRECTIVES RELATED

TO THE TRANSPORT SECTOR

Waste Framework Directive (75/442/EEC) requires States Members to take appropriate measures “to ensure waste utilization or disposal, causing no risk to human health and using no process and methods that may cause a harm to the environment…”.

States Members must prohibit an uncontrolled waste disposal; develop waste treatment plans as well as an integrated and appropriate network of waste disposal equipment. The Directive provides definitions of terms, requirements related to waste accounting, issue of licenses and so on.

Hazardous Waste Directive (91/698/EEC) provides additional and stricter regulations that require taking into account a particular nature of hazardous waste. Hazardous waste should be traced “from the cradle to the grave”, i.e. from the moment of its formation to the moment of final disposal.

Waste is considered hazardous, if it conforms to the categories provided in the Hazardous Waste List. It is prohibited to mix together hazardous waste with non-hazardous waste or hazardous wastes of various categories, except of some specific circumstances. It is necessary to develop hazardous waste disposal plans that would be accessible to the community.

Waste Oils Disposal (75/739/EEC) requires States Members to ensure safe collection, use and disposal of used lubricating oils. The top priority is provided to waste regeneration, then follows waste burning upon the conditions set forth in the Directive and, finally, controlled storage and protection of them.

The Directive prohibits to pour out used oils to water or drainage systems, to store them in the soil and release the harmful oils into it, to practice an uncontrolled disposal of remains of processed oils, to carry out processing of used oils, if it may cause air pollution exceeding the preset limits. Enterprises engaged in disposal of used oils should be provided licenses and enterprises engaged in collection of used oils should be registered and duly supervised.

The Directive on Batteries and Accumulators (91/157/EEC) prohibits sales with any alkaline manganese batteries, where mercury content exceeds 0.025% of weight, except of alkaline manganese batteries for long-term use on emergency (when temperature is below 0ºC and over 50ºC). In such batteries, mercury content up to 0.05% of weight is permissible. The prohibition is not applicable to “button” type alkaline manganese elements and their batteries.


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The Directive also provides certain requirements to sales and disposal of batteries and accumulators, where mercury content of over 25 mg, cadmium content of 0.025% of weight and lead (plumbum – Pb) content over 0.4% of weight in each element take place. Such batteries and accumulators should be marked with a specific chemical symbol specifying content of heavy metals.

States Member should take measures to ensure a separate collection of used batteries and accumulators and easy removal of used batteries from the devices.

The Directive on End-of-Life Vehicles (2000/53/EC) requires limiting usage of hazardous materials in production, collecting, using and processing of end-of-life vehicles and their parts. States Member is obliged to organize used vehicles collection systems and to ensure a transfer of all old vehicles to the enterprise provided with the licenses for their treatment. Old vehicles should be crossed out from the register only upon a presentation of the certificate on disposal issued by the processing enterprise having accepted the vehicle. Manufacturers (importers are attributed to the same category as well) should cover total expenses of processing of old vehicles or a considerable part of them. No charge should be imposed on the proprietor of the vehicle for a provision of the used vehicle for processing. Table 1. The tasks on treatment of waste of taxed products in 2003-2006

No. Description of product Method of treatment Task (in mass per cent) 1. Tires with the weight over 3 kg Processing or other use 80 2. Accumulators Processing 80 3. Mercury lamps Processing 80 4. Galvanic elements Processing In 2003 – 30

In 2004 – 55 In 2005 – 70 In 2006 – 80

5. Fuel or oil filters of internal combustion engines

Processing or other use 80

6. Air filters of internal combustion engines

Processing or other use 80

7. Hydraulic damper Processing or other use 80

Not later than by 1 January 2003, 85% of old vehicles weight should be used, and 80% of this share should be processed. From 1 January 2015, these tasks increase to 95 and 85%, respectively. 3. THE CONDITION OF VEHICLES IN TODAY LITHUANIA

At present, the average age of a vehicle in Lithuania is 13 years. However, more detailed analysis of the vehicle sector shows this indicator to be 14-15 years. In 2003, over 800000 vehicles in Lithuania were 15-20 years old. If this number is multiplied by the average weight of a vehicle (1.5 ton), the resulted amount of waste is tremendous. Taking into account the post-Soviet heritage of buses, cargo-carrying vehicles and agricultural machinery, we are forced to agree that the amount of vehicles unfit for exploitation is really large at present. In 2003, over 20000 imported vehicles were over 10 years old. This number presents over 50 per cent of the total number of imported vehicles. Taking into account that vehicle exploitation usually is calculated for 6-8 years, the problem of utilization of unfit for exploitation vehicles will become very urgent in the nearest future. 4. FACTORS PREDETERMINING A FORMATION OF LESS AMOUNT OF WASTE

At present, it is particularly purposeful to develop an economically reasonable system that would induce collection, use and processing of secondary raw materials, including waste of packages. One of ways of such inducement may be a transformation of the system of taxes for pollutants and waste in the common ecosystem, i.e. it should be necessary to strengthen its inducing (not only income generating) character; to add applicable product taxes to the pollution taxes; to add energy taxes to the pollution taxes. And to reduce, for example, the Profit Tax on the account of the mentioned new taxes for enterprises that treat their waste. Today rates of pollution taxes are too low to induce investments


282

into environmental protection. So, the effect of these taxes for economical subject is not considerable. We hope that the principal causes of such low level of the rates, namely, a lack of information on marginal environmental protection costs as well as political and social arguments, will lose their importance and it will become possible to take actions that will allow to use possibilities provided by a flexibility of the response to the set environmental protection requirements ensured to economical subjects by economical environmental protection measures. 5. PREVENTIVE MEASURES AGAINST A FORMATION OF TRANSPORT WASTE

Manufacturers of vehicles should assess a usability of raw materials obtained from vehicle dumps for manufacturing of specific details, as a production of details of metal, plastics or glass, in their strategic plans. However, a part of vehicle details is not fit for recycling or their processing is not economically reasonable. It includes, for example, cooling liquid, brake shoes, spark plugs or other complex details that require a complicated manufacturing process. In such case, problems of waste of such vehicles should be settled by the state that accumulates unfit for use “transport scrap”. This problem is particularly urgent in Lithuania, where the percentage of old vehicles is very high. Those who had caused it that is by the manufacturers should settle this problem. The way of the settlement – taxes for a vehicle: for utilization and the vehicle itself.

In our opinion, functioning of universal vehicle disassembling sites may be effective. Effective functioning of the said vehicle disassembling sites would be ensures by its complete integration into the whole waste treatment system and well-settled problem of financing. They are “universal”, because sites of such type would include the whole process of utilization of end-of-life vehicles and their exploitation materials as well as control of transport waste treatment taxes. 6. CONCLUSIONS

1. The statistical data attest that the problem of treatment of waste of end-of-life vehicles will become particularly urgent in the nearest future, so it is necessary to prepare us for its settlement today, in accordance with the standards set forth in EU Directives.

2. It is necessary to induce manufacturers and users to initiate processing and utilization of waste of end-of-life vehicles.

3. It is necessary to develop preventive measures to ensure a formation of less transport waste. 4. Vehicle disassembling sites may become a mechanism of transport waste treatment costs

reduction and control. References [1] EUROPEAN PARLIAMENT AND COUNCIL DIRECTIVE on End-of-Life Vehicles 2000/53/EB, issued

on 18 September 2000. [2] “The Programme of Renovation of Lithuanian Vehicle Stock”, the presentation. Vilnius, 2002. [3] Lina Šleinotaitė-Budrienė and Inga Silvestravičiūtė, Kaunas Technological University, Environmental

engineering project “On an Application of European Parliament and Council Directive 2000/53/EB on End-of-Life Vehicles in Lithuania”, Kaunas Technological University Environmental Engineering Institute, 2003.

[4] The Report on the Activities of the Ministry of Environment in 2001, www.am.lt. [5] The Statistical Report on Waste, Ministry of Environment, www.am.lt.


283

THE IMPACT OF ANTI-LOCK BRAKING SYSTEM ON BRAKING DISTANCE OF THE VEHICLE

Valdas Valiūnas, Aurelijus Vestartas


Department of Automobile Transport J. Basanavičiaus Str. 28, Vilnius, LT – 2000 Lithuania

Ph.: (+370)-2744790. Fax.: (+370)-2745068. E-mail: [email protected] INTRODUCTION

Anti-lock braking systems had been developed in order to provide assistance to a driver in avoiding crashes. It is known that anti-lock braking system does not considerably reduce the braking distance, when the road paving is dry, however, increases a stability of the vehicle and possibilities of its control on emergency braking. While braking a vehicle without ABS on a dry road paving, the wheels are locked, but the coefficient of friction is rather high, so the vehicle stops very soon. ABS may even increase the braking distance while braking on loose snow or gravel.

The essential advantage of ABS is its capability to reduce braking distance on wet or slithery way.

ABS causes both positive and negative impact on traffic safety. The statistics show that the probability of “crashes with several vehicles involved” on wet road paving had been reduced by 24% and the probability of fatal crashes – by 14%. However, on the other hand, the statistics also show increase of number of “crashes with one vehicle involved” and “off-going”, as compared to vehicles without ABS. The share of events related to “off-going” with fatal result increased by 28% and the share of crashes without fatal consequences – by 19% [3]. It is difficult to say what should be held culpable for such situation: ABS, improper use of the anti-lock braking system by the driver, reaction of the driver or any other factors. So, scientific substantiation of the statistics requires close investigation.

In the present Paper, the braking distance of vehicle with and without ABS on wet asphalt is compared. Their efficiency is assessed and the corresponding conclusions about the impact of anti-lock braking system on traffic safety are provided. THE CONDITIONS OF THE EXPERIMENT

The efficiency of the service (foot) brake was found using two cars. The experiment was carried out on the straight fragment of road; the speed on the beginning of braking was about 60 km/h. An emergency situation caused by strong stressing of the brake pedal had been simulated. The vehicles of the same age (manufactured in 1993) and approximately same mileage had been chosen for the experiment. One vehicle was equipped with anti-lock braking system (the system was provided with 4 sensors) and the second vehicle was without ABS. Tyres of all vehicles met the manufacturer’s requirements (such as size, internal pressure of tyres and so on). The data on the vehicles are provided in Table 1. The masses of both vehicles were almost the same, i.e. about 1400 kg.

Table 1. The brief description of the data on the vehicles used in the experiment

Brakes Tyres A model of the vehicle ABS Front Rear Type Mark Protector’s

depth, mm Honda Civic No Disks Drums Summer Hankook 6,8 VW Vento 4 sensors Disks Drums Summer Viking 5,9

The following parameters were measured during the experiment: 1. The speed of movement of the vehicles; 2. Braking distances; 3. Control force on the brake pedal.


284

10 tests had been carried out with each vehicle, then the average values had been found on their base.

Force measuring device (K – 614 T – 200 – PCCP – 1 – 219) from the stand K – 208 M was used in the experiment. The case of the device was connected to the brake pedal and the manometer was connected to the steering wheel.

In the experiment, it was found that force of 500 N affects the brake pedal of the vehicle with anti-block braking system. In the vehicle without ABS, wheels are locked during braking. In the experiment on the vehicle with ABS, it was tried to activate the anti-block braking system as soon as possible and to keep the pedal pressing force unchanged until complete stopping of the vehicle. The brakes were pre-heated before the experiment, because the temperature of brake shoes should be about 100ºC according to the methodical requirements [2].

The fragment of road free of dead-water zones on its surface had been chosen for the experiment, because in such zones the braking distance may increase even twice. THE RESULTS OF THE EXPERIMENT

The results of the experiment are provided in Table 2. The braking distance and deceleration of each vehicle are the average values of all performed tests. Table 2. Braking distances and deceleration of the vehicles

A model of the vehicle

Mass of vehicle, kg ABS Braking distance, m Deceleration, m/s2

Honda Civic 1410 No 17,1 8,1 VW Vento 1385 Yes 15,6 8,9

The following formula is used to calculate the deceleration:

12

22

21

12 2 Svv

d⋅−

= ;

where: 1v - the initial speed of movement ( 601 =v km/h); 2v - the speed in the end of the experiment ( 02 =v km/h); 12S - the braking distance.

The results of the experiment in graphical form are presented in Figure 1.

17.1

15.6

14.5

15

15.5

16

16.5

17

17.5

Bra

king

dis

tanc

e, m

1 2

Vehicle No Fig.1. Braking distances for vehicles equipped with ABS and for the cars without ABS

(1 – Honda Civic, 2 – VW Vento)


285

ASSESMENT OF ERRORS OF THE EXPERIMENT

The following factors impact the results of the experiment on measuring braking distance: 1. Wear of the braking system of the vehicle; 2. The system “human – vehicle – measuring device”; 3. The ambient conditions; 4. The inaccuracies of measuring methods. The errors appearing in course of the experiment may be divided into two groups: a) systematic errors, i.e. errors caused by wear and tear of the vehicle brake system, errors of

ambient conditions, errors caused by measuring methods; b) accidental errors, i.e. errors appearing (in this case). in the system “human – vehicle –

measuring device”. Accidental errors of the experiment may be described using several statistical responses [1]:

the arithmetic mean:

nddd

d xnxx +++=

...21 ;

where xd – results of experiments; n – number of tests. The average standard deviation from the arithmetic mean is calculated according to the formula:

nxxx n

222

21 ... +++

=σ ;

where ix – an accidental error of a result of measurement from the arithmetic mean. The probability of detection and error between 1x and 2x may be calculated for the probability

integral function ( )zΦ , where σxz = .

( ) ∫=Φz

dzzz0

2

2exp

21π

;

The results of calculation of statistical responses of accidental errors of the experiment are shown in Table 3. Table 3. The statistic responses of accidental errors of the experiment

A model of the

vehicle

ABS

Arithmetic mean

d , m

The average standard deviation from the arithmetic

mean σ

Probability integral function ( )zΦ

Honda Civic No 17,1 0,91 0,32

VW Vento Yes 15,6 0,82 0,30

After the analysis of the data obtained in course of the experiment, it may be stated that the

vehicle with anti-lock braking system stopped on wet asphalt 1.5 m earlier as compared to the vehicle without anti-lock braking system. The braking distance was reduced by 9 %. So, ABS provides better safety warranty, in particular on wet asphalt.


286

CONCLUSIONS

1. On the base of the carried out experiment, it may be stated that efficiency of anti-lock braking system remains high at low speeds (typical in towns) as well upon wet asphalt conditions.

2. In course of the experiment, it was found that braking distance of the vehicle with ABS reduces by 9 per cent as compared to the vehicle without anti-lock braking system. References [1] Dr. Robert B. Abernethy, The New Weibull Handbook. Florida: Robert B. Abernethy, 2000. [2] 71/320 EEC: The directive of council regulating brake systems for countries members of EU. [3] Insurance Institute for Highway Safety. Antilock Brakes don‘t Reduce Fatal Crashes.

http://www.highwaysafety.org/news_releases/1996/pr121096.htm [4] Memmer S. Braking Distances. http://www.edmunds.com/edweb/editorial/safety/braking.htm [5] Brauer K. Fixing Antilock Brakes. http://www.edmunds.com/edweb/editorial/innovation/ABS.htm


287

LOGISTICS SERVICE DEVELOPMENT AND ITS RESEARCH ASPECTS

Darius Bazaras1, Ramūnas Palšaitis2


Transport Management Department Plytines 27, Vilnius, LT – 10105, Lithuania Ph: (+370)-2745099. Fax: (+370)-2745059

1E-mail: [email protected]

2E-mail: [email protected] INTRODUCTION

Deregulation was primary factor in creation the contemporary requirements satisfying logistics systems. Modern information technologies, global supply and distribution markets and corporate drive asset productivity all converged to shape a new logistics environment. It allowed both the buyer and the seller to introduce wide range of innovations into their relationships.

In the international markets, it is possible for a whole new set of the third-party players to get involved in facilitating the material flows between origin and final destination. One of most important reasons to use the third parties in the logistics channels is growing importance to the firm for focusing its assets on the core business. THIRD PARTY LOGISTICS SERVICE

Third Party Logistics (TPL) – Outsourcing all or much of a company's logistics operations to a specialized company. Third Party Logistics Provider: A firm, which provides multiple logistics, services for use by customers. Preferably, these services are integrated, or "bundled" together by the provider. These firms facilitate the movement of parts and materials from suppliers to manufacturers, and finished products from manufacturers to distributors and retailers. Among the services that they provide are transportation, warehousing, inventory management, electronic data interchange and other third party services. By these definitions TPL appears as an application of the outsourcing concept on the logistics function, in which an outside company provides a considerable part of the logistics service needs of the outsourcing company. But there is something more than outsourcing included in this definition, as it is stated that a bundling of these services is preferred. [1]

Presuming that the company, which is presented in the scheme, is active not only in the sector of client services but in the production and other activities, it is possible to suspect, that the first activity makes the biggest part of all cost (see Fig. 1). Although the preferred number requires additional calculations and arguments, there are theoreticians who think that the costs of the logistics make 70 percents of the final price of the product. Anyhow it is supposed that it is better to dispose the part of the indistinctive activities to another company. Signing the contracts of the cooperation can do this. The contemporary wish to gain the competitive advantage in the market enforces to use the effective strategies – the specialization of the activity is one of them. It is mostly realized as the purposeful focusing on the concrete activity, by both accumulating all resources on it and refusing the activities, which can be refused. And it is not bad that the specialized enterprises appear in the market increasingly. It is possible to think that such companies can lose their positions in the market and to become very pregnable, but it is not true. The specialization makes a good ground to anchor in the market and to concur with others on this base.


288

Fig.1. Time and financial recourses needs for client’s service

IMPLEMENTATION STAGES OF THIRD PARTY LOGISTIC

The preparation phase of TPL establishment is one that is mainly about the shipper doing their homework properly. As outsourcing logistics activities have widespread strategic and organizational consequences, it is important that any decision to outsource is preceded by an extensive analysis of the current logistics system, costs, and service levels, as well as establishing cost service targets to be achieved through TPL. Some authors stress the importance of specifying the scope and types of service that are to be performed by the provider in the future TPL arrangement.

The process of establishing TPL includes the events that lead to identifying TPL as the desired future state. The buying process starts with an identified need to respond to a problem or an arisen opportunity. Common factors behind this are an initiative to enhance customer service, decrease fixed and variable cost, or to increase capacity. It is needful to take to the account the companies' macro and microenvironments, such as enlargement of the European Union, increased competition, higher customer expectations and increasing costs, in conjunction with the shipper's overall business vision and goals, as well as "organizational shake-up". Examples of influencing factors can be connected with the overall strategy of focusing on core business, a desire to ease implementation of structural change (most notably a centralization of the distribution structure, at least in European firms), cost and investment reduction, and service improvement efforts.

The last activity in the first phase is the development of a request for proposals, an activity that is included in all the other descriptions as well. This is the activity in which, according to the authors, much of the work regarding service specification is carried out.

Selection. When the needs of TPL are identified the shipper should identify potential providers, through using multiple sources of information. Financial strength and capability to provide the requested services are important factors for choosing candidates. It can be achieved during the mutual visits and references from external actors as ways of gathering information for the final choice of provider, or the evaluating the proposals of the outside consultants.

Order Preparation

Order Transmittal and Order Entry

Order Filling

Packing for Shipment and Scheduling for Delivery

Shipping Documents Preparation

Transportation

Order Status Reporting


289

In some instances, due to the complexity of the sought-after TPL arrangement, there might not be any providers that are capable of offering the services at all. Rather, the choice may very well be one of finding the candidate that is most apt for developing the necessary capabilities.

Contract. When a provider is selected and the services are specified, a contract between the parties must be signed. It is suggested that a brief main contract is formulated, in which the main terms of the deal are specified. This should be complemented with detailed working manuals, in which tasks, service targets, and such are specified in detail. The routinely contract periods must be of one to three years, but longer periods might be required if suppliers are to undertake major investments for the specific arrangement, they also stress the importance of including an escape clause. Some researchers point out that negotiations and contracting are heavily dependent on the complexity and uncertainty of the arrangement. In some instances, service specification, negotiation of terms and contract formulation might take place during or after the fact, i.e. operations might commence before the formal contract is signed.

Implementation. This phase includes transferring responsibility for provision of the included services from the shipper to the provider. The use of cross-functional teams with members from both organizations is common, as is exchange of personnel for training purposes. The human factor is most decisive for the success of a TPL arrangement, and stresses the importance of transferring routines and competence between the parties. The parties should be prepared that problems not only can, but also will emerge underway, and that it is the responsibility of both parties to work jointly in solving these.

The strictly planned approach is required in order to smoothly implement the partnership; this should be manifested by the writing of a thorough transition plan hi co-operation between the two parties. The written plan should contain directives for issues as comprehensive as the organizational structure of parties, process descriptions and a timetable for events and activities.

While one might surmise that implementation begins at the date and time specified in the formal contract, this is not always the case. In fact, it often starts in the supplier selection stage and can play a prominent role in the final choice of a provider.

Improvement. When the transfer is completed and the provider has assumed responsibility for producing and managing services, the TPL arrangement moves on to the improvement phase. The main activities of this phase are, apart from the provider actually providing the service, are continuous evaluation and development. Education and training, risk and gain sharing, and further development of social bonds are important ingredients. These are basically the activities that include in the last steps of their respective models, the latter however also point out that a TPL arrangement might have to be terminated due to unacceptable service levels or cost.

Renegotiation. When the initial contract period comes to an end it is time for renegotiation. This should be started well in advance of the end of the contract period, as time for evaluating the process should be provided for, as well as allowing for the shipper to develop a new contract and obtain bids from competing service providers. [1] LOGISTICS CENTERS AS PRACTICAL THIRD PARTY LOGISTICS SERVICE CASE

The intermodal and combined transport can be perceived as a concept that is omnipresent while the cargo is transported in swap bodies, containers and semi-trailers. The sea, inland waterways, rail, road and air transport modes are the tools to move the cargo from the place of origin to the destination. The transport modes require loading and unloading areas-ports, different size and purpose logistics centers and cargo terminals where the units will be handled. Once well-functioning internal and external information flows have been added to the transport chains, all the elements of intermodal transport can be assembled.

One of the main objectives of the long term transport development program is to develop a framework for an optimal integration of different modes of transport in the regional logistics centers so as to enable efficient and cost-effective use of the transport system through seamless, customer-oriented door-to-door services, favoring competition between transport operators and cargo owners.

Intermodality and logistics are not oriented to the forcing of a specific modal split, but rather to improving the connections between all modes of transport and integrating them into a single system providing optimal use of rail, road and short sea transport in order to meet modern logistics requirements for door-to-door deliveries.


290

Intermodal transport and regional logistics centers in Lithuania will find their market place among the conventional international longer distance railway and water transport and the local shorter distance transport market that is ultimately suited for road transport. Shipments that depend strongly on early and/or timely delivery (time-sensitive, high value goods) in general favor road transport, whereas shipments requiring primarily the lowest possible transport costs (cost-sensitive, large quantities of lower value goods) can generally be well-served by the rail or maritime transport. Intermodal, i.e. combined rail/road or combined maritime/road transport unites the strong sides of the different modes. The advantages of the rail and water maritime transport (relatively low costs, high capacity, safety, energy efficiency and low environmental pollution) are combined in the regional logistic centers with road transport (high flexibility, speed, organizational simplicity of door-to-door transport).

The organizational simplicity for the shipper of goods, once various organizations involved in the regional logistics centers have properly organized and coordinated their activities, has been the main driving force for the creation of the logistics centers and growth of intermodal transport.

Both, for the supplier and the user of regional logistics centers services and of intermodal transport, and for the society as a whole the development of logistics centers and intermodal transport has proven to offer substantial benefits, particularly because of their (relative) quality or the relative merits of the (competing) transport modes constantly developing in an operating environment subject to continuous change, such as increasing congestion on the road network, or the introduction of new pricing policies and/or regulations. [2] CONCLUSION

One important aspect of change processes is the distinction between the strategic and operative areas, which are a figurative representation of the constellations in which decisions on change and the implementation thereof, take place. Designs and decisions conceived in the strategic area are manifested in operations, i.e. there is a link between the two areas. There might also be activities in the one area that take place without link to the other, but from an overall systems perspective the design of the distribution system in the studied case - which was establishment of TPL and centralization of distribution - was conceived on the strategic level and manifested on the operative.

There is also the distinction between formation and implementation. Depending on the models of change that are at play in a change process, these two process constituents are of different character, but both exist to some extent in any given process. In the description of the process it is concluded that it can be divided into four main chronological episodes. The first two of these Recognition and Decisions - involve no operational manifestation of change; this takes place during the third and fourth episodes, Transfer and Operations. Therefore the process can on an overall level be seen as having involved two main phases, the first being formation during which activities, actions and events aimed at formulation solutions and gaining acceptance of the planned change are carried out, and Implementation, during which most of the operational manifestation of change takes place.

There are a number of important factors that are going to affect the development the shipper/ third party relationships in the nearest future:

• in order for a relationships between the shippers and third party to be effective in the context of partnering, there must be a clear understanding on the part of both parties regarding mutual expectations;

• both the shipper and third party must establishing the technology interface - the best technological resources of both parties must be utilized to insure efficient and effective implementation;

• the relationships in the respect is evolutionary and tends to grow in the scope and complexity over time. The range and cost of available technology will encourage this general trend toward expanded value added services on the third party;

• the most progressive third party firms must develop strategic alliances with partners in other EU countries in order to provide an “end to end “ service in international markets; References [1] Lindskog M. Changing to Third Party Logistics. Prentice: Institute of Technology, Linköping University,

2003, p. 140. [2] Palšaitis R., Bazaras D. Analysis of the Perspectives of Intermodal Transport and Logistics Centers in

Lithuania, Transport, Vol. XIX, No. 3, 2004, pp.119-123. ISSN 1648-4142. (Journal of Vilnius Gediminas Technical University and Lithuanian Academy of Sciences).


291

FORECASTING OF THE FREIGHT TRANSPORTATION BY LITHUANIAN RAILWAYS

Daiva Griskeviciene1, Algirdas Griskevicius1, Albertas Simenas2

1 Vilnius Gediminas Technical University

Transport Management Department, Plytines Str.27, Vilnius LT-10105, Lithuania

Ph: (+370) 5 2745099. Fax: (+370) 5 2699714. E-mail: [email protected] 2 JS Company “Lithuanian Railways”

Mindaugo Str. 12/14, Vilnius LT-2600, Lithuania Ph: (+370) 5 2693303. Fax: (+370) 5 2693261. E-mail: [email protected]

INTRODUCTION

Aim of this article is to analyse evolution of freight and passenger transportation by Lithuanian railways as well as market development opportunities, to foresee perspectives of transportation activities and to present forecast of freight and passenger transportation up to 2020.

To this effect an analysis of freight transportation market and of its changes was carried out, as well as the current status in the Lithuanian railways was examined. Based on the analysis of development indicators of the Lithuanian railway transport sector in 1997-2003, the SWOT analysis (of strengths, weaknesses, opportunities and threats) was carried out. The most important factors and premises, which form a basic foundation for the long-term railway transport strategy, were identified.

In order to form a perspective, the study was based on macro-economical indicators of the Lithuanian economy, of their evolution and forecasts. Also, external and internal factors having impact on the evolution of freight and passenger transportation were analysed, perspective directions were put forward, and as well as possible risk factors were identified. When determining long-term freight transportation forecasts, references were made to the “Long term strategy of the Lithuanian transport development (up to 2025)”, which was prepared on the basis of factors and assumptions, arising out of an analysis of tendencies of the Lithuanian economic and transport sector development and out of the general forecast. Besides, the newest development tendencies of the EU transport sector were taken into consideration, as well as economic evolution (Basel) scenarios and (Lisbon) strategy directions and methods.

When preparing long-term forecasts of the Lithuanian railway transport development, three possible growth scenarios of the Lithuanian economy – 1) an optimistic, i.e. of a speedy economical development, 2) the basic, i.e. of a realistic economic growth, progressing towards moderate tendencies (based on the scenario of the Ministry of Economics), 3) a pessimistic, i.e. of a slow economic growth, were assessed. When preparing forecast of the modal split, references were made to the forecast of total freight transportation volumes contained in the Long-term strategy of the Lithuanian transport development up to 2025. 1. ANALYSIS OR RAILWAY TRANSPORT ACTIVITIES

The country’s main and the biggest railway transport company AB “Lithuanian Railways” carries out freight and passenger transportation, development and maintenance of infrastructure, traffic organization and control, technical supervision and repairs of the rolling and traction stock and other services related with these activities.

Increased freight transportation volumes (43.4 million tons of freight) in 2003 exceeded transportation volumes by 18.5% of 2002. The flow of international freight increased by 26,0% and amounted to 38,0 million tons. Local transportations during the year decreased by 16,2% (up to 5,4 million tons). International transportation was distributed as follows: 7,2 million tons of freight were imported, 7,1 million tons of freight were exported, and 23,8 million tons of freight were transported


292

by transit. Amongst the factors determining these changes in local and international transportation volumes were the changes in the transportation of oil and oil products: bigger volumes of oil were transported by local routes in 2002, whilst a greater part of oil freight was exported in 2003.

Local carriages in freight transportation accounted for 12.5%, export for 16.2% and import for 16.5%, whereas transit in freight transportation constituted the greatest share of 60.8 % (Table 1). Table 1. Freight transportation by Lithuanian railways in 1997-2003

1997 1998 1999 2000 2001 2002 2003

Total freight transported, in thsnd. tons

30498 30912 28347 30712 29173 36650 43447

Of which: Local transportation 4720 5977 4595 4664 6340 6481 5435 International transportation 25778 24935 23752 26048 22833 30169 38012

Of which: import 4581 4977 4317 3961 3410 4898 7176 export 5495 6210 4359 4099 4273 4476 7053 transit 15702 13748 15076 17988 15150 20795 23783 Freight turnover, in mln. tarif. tkm 8622 8265 7849 8918 7741 9767 11457

Average distance of one ton transported, km 283 267 277 290 265 266 264

Freight turnover, in mln. oper. tkm 8933 8658 8169 9233 7917 9936 11523

Oil and oil products constitute the main share of freight transportation by Lithuanian railways

(44.8% of the total freight transportation volume). Transportation of this type of consignment, as compared to 2002, has increased by 25.2%. Chemical and mineral fertilizers accounted for 14.2%, and ferrous metals for 8.3% in the total freight transportation structure, and increased, correspondingly, by 17.6% and 4.6%. Also, a volume of construction consignments and cement increased by 12.6%, of grain and flour by 22.5%, of coal and coke by 18.7% and of foodstuff consignments by 6.4% (chart 1).

Goods carried by railways in 2002 by kind of goods, thous. t

2607

,3

1281

6,9

7

1755

,7

199,

6

3684

,9

0,2

2,916

65,2

3583

,7

69,7 95

4,9

705,

7

1936

,3

141,

5

1338

,1

0,2 43

1,1

41,8 11

91,2

383,

2

1135

,3

659,

1

1338

,3

02000400060008000

100001200014000

National transport

Crude petroleum and petroleum products CoalFerrous metals including scrap-iron Non-ferrous metalsChemical and mineral fertilizers Chemicals and sodaBuilding materials TimberPerishable food products Other food productsGrain and flour Other goods

International transport

Chart 1. National and international goods transportation by Lithuanian railway transport in 2002


293

The main directions of freight transportation are concentrated on the Trans-European corridor IX: 31.7 % of freight is transported through Klaipeda port, 65.8% in Kaliningrad direction and as little as 2.5% of the remaining freight is transported in other directions.

Growth tendencies in freight transportation also persist in 2004: freight transportation by JSC “Lithuanian Railways” has increased by 13.1 % during 1st quarter, transit increased by 5.8%, and export by 38.1%. 2. COMPLEX ECONOMIC ANALYSIS

The results of analysis on the evolution and current status of the Lithuanian railways core businesses, i.e. of freight transportation and of passenger transportation, are evaluated with the help of the analytical form in order to identify further development opportunities: Strengths:

1. The upgraded and reconstructed railway transport infrastructure going alongside Trans-European transport Corridors I and IX crossing the territory of the country creates favourable conditions for freight transportation and international freight and passenger transportations;

2. The upgraded and developed non-freezing Klaipeda sea port generates freight flows the main share of which is transported by the Corridor IXB railways;

3. Good political and economical relations with the neighbouring countries foster cooperation in freight transportation and passenger transportation by rail, implementation of combined carriages;

4. Due to favourable transportation conditions, branch of corridor IXD is intensively operated for transporting CIS freight and passengers through the territory of Lithuania;

5. The completed fundamental restructuring of the railway transport sector will enhance performance of operation, and will induce investments into the railway infrastructure and upgrading;

6. The improved training, qualification maintenance and advancement system of workers in the railway sector allows to achieve higher performance standards and to create more qualitative services;

7. New tourism opportunities, opened up together with the membership in EU, will increase the need of services for international and local communication by rail.

8. Qualified scientific potential of the transport sector, which prepares feasibility studies of different transport branches and participates in preparing programs and projects.

Weaknesses 1. Outdated railway freight and passenger rolling and traction stock; 2. Poorly developed network of electrified passenger railway lines, insufficient for freight

transportation; 3. Poor communication by rail with EU countries through Poland (different gauge width),

absence of the European gauge line into the depth of the country; 4. Passenger transportation is not coordinated with the services of other transport modes; 5. Legal basis for regulating the upgrading and development mechanism of the transport

infrastructure by applying principles of the private- public capital has not been prepared; 6. Great competitiveness of the road transport, especially of automobiles, based on higher

communication speeds and technologically developed interoperability among individual passenger transportation modes;

7. Insufficiently efficient interoperability between Klaipėda seaport and the Lithuanian railways, and insufficiently developed railway network in the port.

Opportunities 1. To improve and comply with EU the legal and normative basis in order to create favourable

conditions for developing and upgrading the Lithuanian railway transport sector; 2. To create logistics centres in Kaunas, Klaipėda, Panevėžys and Vilnius and to integrate them

into the transport logistics network of the Baltic sea region; 3. To achieve the status of the Trans-European network for the most important trunk-roads of

Lithuanian railway transport; 4. To cooperate with the subjects of transport services in the continental Europe market;


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5. To strengthen agents’ and expeditionary services by increasing freight flows in the East-West direction through Klaipėda and Kaliningrad ports and realizing economical interests of Lithuania and of enlarged EU.

6. To improve and to upgrade commuter passenger communication by creating new quality of services and introducing a new ticketing system;

7. To upgrade traffic command and control systems, by ensuring traffic safety and increasing capacities of infrastructure.

Threats 1. Insufficiently efficient action coordination with neighbouring countries when developing

Trans-European networks; 2. Deepening public passenger transportation crisis due to decreasing number of passengers, i.e.

situations of a delayed public transport adjustment to the rearranged layout of production forces and the changed situation of planning cities and settlements;

3. Neighbouring countries’ (especially Russia’s) ambitious national plans and programmes incongruent with the interests of Lithuania and EU in developing the sea transport (ports, logistic centres, sea highways) and railway transportation;

4. Limited railway opportunities to compete in the transport market with the carries of the liberalized “cheap ticket” air transport system;

5. Unbalanced railway tariff policy with neighbouring countries; 6. Political decisions are seldom based on careful studies and necessary research and analysis of

an object.

On the basis of SWOT analysis goals and means of further railway transport system network were envisaged seeking to make the Lithuanian railway transport sector competitive by satisfying growing needs of both markets of transport services, the Lithuanian and that of enlarged EU. 3. MAIN TRENDS OF THE LITHUANIAN RAILWAYS STRATEGY

Main goals of the long-term development of the railway transport: • To prepare a legal basis and to establish institutions for market regulation necessary for

Lithuania’s integration into the European Union; • To complete restructuring and its partial privatisation of the railway enterprise; • To create a strong and efficient safety control system; • To create a uniform environment protection system for the railways, encompassing all

possible (air, water, soil) pollution sources; • To upgrade the infrastructure for its efficient integration into the European Union

transport system, and to carry out upgrading works according to AGC and AGTC agreements;

• To restructure railways according to EU directive 91/440 and to the supplementing directives 2001/12EB, 2001/14/EB, 2001/16 /EB, in order to increase the competitiveness of railways in the European market of transport services.

• To acquire passenger and freight rolling stock to meet the parameters of the upgraded infrastructure.

In order to be able to get integrated into Trans-European railway network structures successfully, and to reach a high speed of trains and a maximal traffic safety, to implement EU requirements for environment protection, to ensure efficient communication between the West and the East by railway transport by providing passenger and freight transportation services, it is necessary to be guided by the European Parliament and Council directive 2001/12/EB regarding the Community’s railway development and to continue implementation of the envisaged measures in 2004-2008.

Railway security insurance. The railway sector has always been safer than that of the roads. This is proved by statistical data. The increasing need for international services and interoperability of the system, together with the opening up of the market, caused the need to toughen an attitude towards the railway security. Mutual interoperability of the systems should ensure the same or even bigger safety level, than it is achieved in each state. Namely because of that safety is declared as one of the most necessary requirements of operating the Trans-European railway system, which is laid down in


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the directive 96/48/EC on interoperability of the Trans-European high-speed railway system and in the directive 2001/16/EC on interoperability of the Trans-European conventional railway system.

This induces to take up parallel actions on two levels: - on the technical level it is necessary to define standards for each component of the railway

system (rails, rolling stock, signalling system, work procedures, etc.). This is the role of the “directives on interoperability”;

- on the administrative level it is necessary to specify duties and liabilities of all workers of the system, starting with the managers of infrastructure, and finishing up with representatives of the communication institutions (without forgetting representatives of railway companies and state institutions). Making reference to the safe traffic programme of AB “Lithuanian railways” that is planned in order to submit for consideration in the near future should do this. 4. FORECAST OF FREIGHT TRANSPORTATION

Factors forming the main freight transportation flow: 1. Local freight transportation. The market of local freight transportation is formed by the country’s major enterprises, i.e. the

main clients, the changing commodity structure, distribution of freight transportation among transport modes and the share of freight transportation flows falling on the railway, what is often conditioned by a possibility of access to the railway lines/stations and by an average distance of transportation by rail in the total transportation.

2. Freight export and import Freight export is determined by export of international trade, by its spectrum, the production

potential and competitiveness of the country’s economy, foreign demand of exported goods. Freight import is determined by the country’s demand for imported goods and by consumers’ purchasing power or financial capabilities.

3. Freight transit Freight transit forms the main flows in the East-West direction: the direction to Kaliningrad area

and to Klaipėda seaport. The transit flow by rail in the North-South direction is insignificant, however, huge EU and Lithuanian investments are directed namely towards the construction of this direction railway line.

4. Combined transportation Combined inter-modal transportation is a direction of a modern technology. The crucial share of

the services falls on the railway transport. To this effect, transportation by containers is fostered, and special rolling stock is purchased, shuttle freight trains are being organized.

5. 5. Freight terminals. Freight stations are being upgraded in the railway transport; the technology of interoperability

of two different systems is being improved. Lithuania needs universal logistics centres, multi-modal terminals, and freight villages. Projects of freight terminals were developed for Klaipeda, Kaunas and Vilnius cities.

Factors having a negative impact for changes in freight transportation: 1. Renovation and upgrading of the freight rolling and traction stock. 2. Upgrading of the railway infrastructure in compliance with AGC and AGTC requirements. 3. Integration of the railway network into Pan-European networks. 4. Upgrading and improvement of the traffic safety system. 5. Balancing out of the environment protection system in the railway (pollution of air, water,

soil). 6. Implementation of restructuring of the railway sector. 7. Creation of the legal and normative basis of railway operation. 8. Implementation of requirements of EU directives 91/440, 95/18, 2001/12/EB, 2001/14/EB,

2001/16/EB and of other legal acts in order to liberalize the Lithuanian railways, to enhance their competitiveness in the market of European transport services, to technically improve and technologically upgrade, by ensuring safety and environment protection.

Premises for the freight flow increase:


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1. Development of the Lithuanian economy, and a positive development of its separate sectors, the development of industry, agriculture, local and international trade.

2. Membership in the European Union, harmonization of business activities with the social indicators.

3. Opening up of the production and consumption markets of EU states, geographical and quantitative development.

4. Increase of the purchasing power of residents of the newly joined EU states; 5. Recovering and reformed economy of CIS, especially of Russia and of Ukraine, where the

pushing force of economic relations passes from the politics and the state control into the field of private initiative and economic decisions.

6. Russia’s accession into the World Trade Organization should catalyse international agreements concerning railway cooperation, including the tariffs.

7. The reviving demand and purchasing power of the consumer society of the Eastern neighbouring countries will boost exports of Lithuanian goods.

External risk factors: 1. Adversarial economical and political decisions of CIS bloc countries concerning

commercial-transport relation’s with/through the states newly acceded to the EU. 2. Construction and upgrading of the new Russian sea ports on the Eastern Baltic seaside

will increase competition for Klaipeda port, as a result of which freight transit may decrease by the Lithuanian railways;

3. Instability and insecurity of the foreign banking sector, especially, in the regions of economically instable states may cause fluctuations in the market demands;

4. Fluctuation of oil supply and oil prices and instability of the market, linked with the military, political and economic situation of the world and of the neighbouring states which govern industrial enterprises;

5. Threat of terrorism immobilizing transport- commercial relations even in neutral states; 6. Instability of the USD and possibly, of other main currencies prevailing in financial

settlements with the Eastern neighbours due to recurrent political-economical crisis in the regions of the world.

5. THE LITHUANIAN FREIGHT TRANSPORTATION MARKET

The Lithuanian market consists of 22 % of local freight transportation and of 78 % of international transportation. 5436 thousand tons of freight were transported in the domestic market, and 23783 thousand tons of freight were transported by transit through the territory of Lithuania in 2003, whereas export and import distributed nearly evenly, i.e. 7053 thousand tons and 7176 thousand tons, correspondingly. All international transportation amounted to 38012 thousand tons of freight

In the future smaller volumes of freight, as compared with international freight transportation, will fall on the railways in local transportation, since the main transportation in the domestic market is carried out by the road transport .The increasing competition within the market of the road transport services itself, induces enlargement of enterprises, expansion of the quality and spectrum of services. Meanwhile, the road transport competitiveness will increase against the railway transport, for which freight transportation distances within the country’s market are too small due to a small territory of Lithuania. However, the growth of the country’s economic potential and increase of the consumer market will be the crucial factors for increasing the plenitude of goods and volumes of their transportation.

If daily consumer goods are transported by specialized road transport vehicles, the production of major industries are transported by rails in as much there is access to the railway lines. It is expected that the domestic market of services will be stabilized and will remain in the same level in the near future. Therefore, a current share of the local freight transportation in the domestic market falling on the railway transport should also remain in the future.

In the railway transport, Lithuania is related with the neighbouring Baltic States by the common project of developing the European level infrastructure, which should revive a comparatively passive transportation of international freight by the surface transport, especially by railways, in the North-South direction. Completion of the project Rail Baltic throughout all three Baltic states together with


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Finland and Poland will not only create necessary conditions for a modern transportation and loading of freight, but will actually integrate this remote economical region into the common railway networks of EU states.

The growth of economies of the Central and Eastern European countries has gained an ever-accelerating rate as compared with that of the developed Western European neighbours. In the opinion of experts of EU structures, the main macro-economical indicators in the acceded states should retain their regular growing tendencies: the GDP of the countries will grow by 4 % per year, foreign trade by 7% per year.

Trans-European I Corridor connects national markets of the Northern EU states with the Central and Eastern, and further on, with the Western and Southern European states’ markets. This is a direct international connection among the majority of EU countries. The already functioning automobile highway Via-Baltic activated transit transport flows through Lithuania. It is expected that the constructed railway trunk road Rail-Baltic will become an actual axle connecting the nucleus of Europe with the more Northern states.

Western European states, belonging to the common EU market, have different levels of economic development, and the economical growth of these countries has stabilized at a small rate of GDP growth. 1,5% growth was achieved in 2004. Forecasts approved by EU structures indicate 2% annual growth rates, however, it is expected that international trade should reach an average 4,1% growth rate.

Russia’s economy is manifestly recovering from the financial crisis of 1998. Although the domestic market suffers due to devaluation of the national currency, great hopes were entailed by the growth of prices in oil export in the world market. During the last 5 years, an average GDP growth was approximately 6,5%. Recovery of non-ferrous metallurgy, agricultural, foodstuff and retail sale industries gives hopes for the further growth of the GDP (table 9). The Russian Ministry of Economic Development and Commerce envisages that the country’s economy will develop at a rate of approximately 5 % of annual growth during the next 20 years, if the tendencies of 8-9% of investment are be retained.

Russian export will increase more significantly than import. Export of oil, natural gas, metals and other raw materials will be continued further on. In recent years, raw materials and semi-fabricated goods constituted approximately 70% of the Russian export.

Export to Lithuania decreased insignificantly, as well as import increased insignificantly. Russia’s regular economical and political interests connect Russia by transport ties with its

Kaliningrad area. Freight transportation and part of passenger communication is going on by the main Corridor IXD-IXB, which connects them through Lithuania. This is the shortest and the most economically acceptable way to communicate with a geographically remote Russian area. The results of recent years demonstrate that Russia’s freight transportation through Klaipeda port is regularly decreasing and it is increasing towards the Kaliningrad area

Russia’s transit through Lithuania from/ to Klaipėda port is related with the changes in the country’s national policy. The Russian government plans to better use possibilities of the current port and the ports being newly built and to provide them with a sufficient load of cargoes. Such tightening up of the political direction of the planned economy is a characteristic and usual tool of Russia’s economic policy. As result, transfer of part of the usual freight flow in Klaipeda direction to other railways (table 8) has been tangible in recent years. The further stability of freight flows is related only with the interests of the Russian businesses in specific ports of the Baltic Sea, e.g. Ventspils. Lithuania, on the contrary, having only one port, retained the national ownership of the port infrastructure during the entire period of independence and provided services to the country’s businessmen. It is evident, that Klaipeda port and the railway corridor IXB towards it may experience a decrease of freight volumes due to the above-mentioned political steps of Russia.

Byelorussia is the closet Lithuanian neighbour from the Eastern side. After formation of CIS, this country of extraction of natural resources and machinery industry starts to gain speed in the evolution of economical development during the last three years. Due to strict planning and control, the Byelorussia economic evolution is related more with political decisions, rather than economical levers. Irrespective of a difficult economic-social situation after the financial-economic crisis, long-term economic instability, the Byelorussia economy is gaining speed. If the state succeeds directing the planned and sufficient investment into upgrading of the national plants instead of exporting the production means abroad, then it is probable that the country may achieve a far speedier development


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rate, than it is foreseen by economic-financial institutions, as compared to the evolution scenario of the Russian economy. However, the further perspective of the country’s evolution during the next decade is related more with the investments of the national origin, therefore it is probable, that the growth proportions should remain more moderate.

Freight transportation between Lithuania and Byelorussia had a tendency to increase up to 2003 until reached 7,8 million tons per year. Freight flow by IX Corridor is distributed in two directions: by IXB corridor to Klaipeda port and by IXD Corridor to the Kaliningrad area. 4/5 of the Byelorussia total transit is transported by IXB corridor to Klaipeda port; meanwhile 1/5 of transit freight is transported to the Kaliningrad area. In 2003 the flow of transit freight in Klaipeda direction decreased by 4,5%, and it increased by 22,5% by the Kaliningrad corridor.

Ukraine’s economy has been developing intensively during the last three years. The GBP increased by 4,8% in 2002, and by 5,4% in 2003. It is expected that GDP will increase by even 8% in 2004. However, evolution of the country’s economy greatly depends on the course and results of the structural reforms. At present, 30,5% of the GDP is created by the industry, and 13,4% is created by agriculture. Foreign trade has reached an annual growth of 10% under present prices. Around half of export consists of metals and mineral cargoes. 41,5% of the total import consists of the mineral cargoes.

Based on the essential conditions of the economic evolution, it is forecasted that Ukraine’s freight transportation will increase correspondingly to the evolutions of the GDP and economical-political conditions

Lithuania’s transportation connections with Ukraine are starting to develop more intensively. Freight transportation by rail increased in import, export and transit through Lithuania.

The increased import from Ukraine to Lithuania demonstrates increasing commercial interests of the latter and cooperation development with the Ukrainian manufacturers and businessmen. This is confirmed by transit, which increased twice during the year, and by export from Lithuania, which increased by 1/3. The structure of the main cargoes, transported by railways, remains the same.

Market of the Central Asian states starts to recover after an economic crisis which followed the reformation of the Soviet states into CIS. Russia’s financial crisis of 1998 had a negative impact for the recovering economies of these countries. However, the again strengthened Russia’s economic situation in the field of world oil trade and exported raw materials helped to recover economies of other CIS countries. Market success of the Central Asian countries is based on the extraction of energy and mineral raw materials and on manufacturing and trading in consumer goods, which is still very vulnerable to the impact of external markets. Due to Russia’s great impact and a speedy development rate characteristic to the developing countries, quite a fast economic rise is expected from the low social –economical level, which is close to a number of CIS countries.

Kazakhstan is one of the Central Asian states, which has transport relations with Lithuania. Kazakhstan’s freight exported to Lithuania decreased by 61,9%, and import from Lithuania increased by 192,5%. Kazakhstan’s transit through Lithuania decreased by 13,0% during 2003. 6. GENERAL FORECASTS AND TENDENCIES OF INTERNATIONAL FREIGHT

TRANSPORTATION

Forecast scenarios: Premises for an optimistic scenario:

1. Freight transit through Lithuania gains growth tendencies due to the improved economies of CIS states;

2. International freight transportation increases due to the established normal economic cooperation relations with all neighbouring and major states and due to activated foreign trade in the European Continent and in the whole world;

3. As a result of implementation of investment projects into Klaipėda sea port, opportunities of the port are developed, what activates freight loading and big ship servicing, and the infrastructure is prepared for the application of more modern technologies;

4. Thanks to great investments into the Lithuanian railways, the upgraded infrastructure and rolling stock ensure safe and speedy freight transportation in compliance with the EU standards.


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Premises for a radical scenario: 1. The level of freight transit through Klaipėda port does not change since the port and

railways reinforce their positions in the international freight market; 2. Russia’s connection with Kaliningrad will be consolidated, transportation volumes will

increase due to the reviving economy of the Russian Federation; 3. After Russia’s accession to the World Trade Organization, tariffs and solutions

discriminating the Baltic countries’ railways will be cancelled; 4. The Lithuanian railways are developed by investing into them all envisaged resources; 5. The Lithuanian international trade is intensified due to integration onto the common EU

market, and simultaneously, into the world market; 6. After construction of the European railway trunk-road Rail Baltic, regular freight

transportation in the North-South direction through the territory of Lithuania begins; 7. The railway transport maintains its positions in the market of local transportation.

Based on these main premises, the three main scenarios of an economical evolution of the Lithuanian railways for up to 2020 have been formed, which specify the environment, under which freight transportation by the Lithuanian railways is expected to develop. Forecasts have been calculated for total freight flows, local and international transportation: export, import and transit. Since freight transit by the Corridors IXB and IXD has been formed long ago and has some structural and origin differences, forecasts for these flows were calculated separately. Besides, seeking to identify the railway transport share in total transportation, modal split in freight transportation is forecasted (table 2). Table 2. The actual data and the forecasts of freight transportation by the Lithuanian railways (thous. t)

1999 2000 2001 2002 2003 2004 2005 2006 2007 2010 2015 2020 Local freight transportation 4595 4664 6340 6481 5435

Forecast 5521 5641 5767 5901 6290 6880 7358 International freight transportation:

1. Import 4317 3961 3410 4898 7176 Forecast 7195 7293 7651 7840 8435 9536 10190 2 Export 4359 4099 4273 4476 7053 Forecast 7119 7296 7383 7579 8139 9065 10212 3. Transit 15076 17988 15150 20795 23783 Forecast 25554 26685 27570 28620 30561 33986 38993 Total transit to/from Byelorussia, Russia, Kazakhstan and Ukraine through Klaipeda

7684 7260 7322 7753 7641 7806 8544 9535 11319

Transit to/from Byelorussia, Russia,Kazakhstan and Ukraine in Kaliningrad direction

13756 16338 17239 17938 18707 19320 20201 21448 22142

Total international freight transportation

23752 26048 22833 30169 38012

Forecast 38568 39274 40604 43039 47135 52587 56914 Total transportation of freight by Lithuanian railways

28347 30712 29173 36650 43447

Forecast 44089 44915 46371 48940 53425 59467 64272


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CONCLUSIONS

1. The complex SWOT analysis of the present economical situation corroborated the optimistic tendencies of the freight transportation by Lithuanian Railways.

2. The rate of economics development of European Union and the joint states corroborate the possibilities of the increasing of freight transportation by railway transport.

3. On the results of restructuring of JSC „Lithuanian Railways“ the assumptions are created for the increasing of freight flows, improvement of the service quality, increasing the speed and security of transportation.

4. The forecasts scenarios based on the internal factors and external assumptions create the conditions for reliability of forecasting of future freight transportation by railway transport even until year 2020. References [1] Long-term Strategy of the Lithuanian Economical Development for 2015. Government of LR, 2002. [2] Long-term Strategy of the Lithuanian Transport Development for 2025. VGTU, 2004. [3] Forecasts of Freight and Passenger Transportation Volumes by Lithuanian Railways up to 2020. VGTU,

2004. [4] EC DG of Energy and Transport. European Energy and Transport – Trends to 2030.

Information Technology in Transportation and Education


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INFORMATIONAL MODELLING OF THE REGULATIONS OF THE DANGEROUS FREIGHT TRANSPORTATION

FOR DATABASE MANAGEMENT SYSTEMS

Nijole Batarliene

Vilnius Gediminas Technical University Plytines 27, LT-10105 Vilnius-16, Lithuania

Tel.: +370 2744778, Fax: +370 2745059 E-mail: [email protected], [email protected]

1. INTRODUCTION

The purpose of this article is to show theoretically and with certain examples the coherence of database management systems’ (DBMS) schemes and restructured dangerous freight transportation regulations’ base. From the one hand, such coherence requires restructuring regulations into DBMS acceptable structure, and from the other hand – lets forwarders to use database to know how to transport certain dangerous substances.

Restructure of dangerous freight is made neither by scientific organizations, which work, in this particular direction, nor is described in specific literature. Usually text of dangerous freight transportation rules is just changed by means of computer. Therefore, restructure theoretically and practically is a new subject.

There is a plenty of international dangerous freight transportation rules, which are very complicated and inconsequential. It is because of the following reasons:

Big number and amounts of dangerous freight and its’ compounds; Properties of different dangerous freight and its’ compounds are often partly or completely

similar; Position coding method well known several decades ago isn’t effective nowadays, because

of the ever-growing number of substances, compounds and their classes; there is a lack of positions in substance’s code to indicate new materials and their properties [1].

Bearing this in mind, first of all, dangerous freight transportation rules should be restructured. 2. RESTRUCTURE MODEL OF DANGEROUS FREIGHT TRANSPORTATION

RULES

Restructure is understood as changing dangerous freight transportation rules’ structure into the self sufficient elementary dangerous freight transportation regulations’ system.

Basic principle of restructure is simple. As dangerous freight transportation rules are based on UNO declared code list of dangerous substances and their compounds, selecting certain dangerous substance’s or compound’s code, it is possible to find out in the rules how to transport one or another substance or what is prohibited during transportation of this particular substance.

Let dangerous substance’s name, code and transportation regulations be:

iiii TNNN →−+ )()()( . (1)

Here: T – is name of substance, i – UNO code of this material (0001≤ i ≤ 9999),

)( +N – regulations, requiring one or another type of transportation, parameters, etc. )( −N – regulations, prohibiting one or another transportation of dangerous substance,

)(N – technical constants, parameters, units of measure, etc., used not only in transportation of dangerous freight.

From expression (1) we can see, that separate regulations of different substances are similar:


303

,11ql

ql nn ≡ (2)

where q1 ≠ q; l1 ≠ l.

It is obvious that the same technical parameters can influence different dangerous freight transportation.

)( +N and )( −N in the expression (1) have only formal differences, because it is not important if transportation regulation confirms the requirement or denies. It is important that regulation would be undividable. Let us say, that a certain regulation consists of two parts:

ql

ql

ql nnn

21 ,= . (3)

Then, it is clear that for i1 substance only qln1

part of regulation is valid, and for the i2 - only qln2

part of regulation is valid. Because both parts of regulation have the same code qln1

, therefore for i1

substance qln2

part of regulation and for i2 substance qln1

part of regulation would be incorrect,

misleading. It seems that such classification of dangerous freight transportation regulations would allow

transportation process participant (forwarder, packager, fright-forwarder, etc.) to define himself which transportation regulations are necessary to transport a particular dangerous substance. But it’s not the way it is. Because of big number of regulations, their complicated formulation and very frequent dangerous freight transportation regulations’ changes by competent organizations, the only person able to define all transportation parameters is specialist-expert. Dangerous freight forwarders unable to use services of such experts for each separate transportation because of physical and financial reasons. To solve this problem it is needed to create dangerous freight transportation regulations’ database from those regulations, which are practically required for transportation participants. The sphere of competence of the experts would stay juridical debates concerning breaking rules and development of dangerous freight transportation strategy in the country [2].

Extending expression (1), we have a list of dangerous substances as well as big number of their transportation regulations:

LLLLLLLLLLL

L

L

LLLLLLLLLLL

L

L

ikiii

ikiii

k

k

Tnnn

Tnnn

Tnnn

Tnnn

i

i

→

→

→

→

−−−−−

, , ,

, , ,

, , ,

, , ,

21

112

11

1

2222

12

1121

11

1

2

1

(4)

Obviously, when new dangerous substance appears, it’s not difficult to continue the list (4):

11

12

11

1 , , , ++

+++ → ikiii Tnnn iL .

Let any code of substance be R, where 1 ≤ l ≤ i, row number – 1 ≤ q ≤ d, where d is maximum row number of a certain substance, which has the biggest number of regulations.

3. DATA STRUCTURE

In expression (4) all regulations are classified into several groups according certain similar

dangerous freight parameters and the same transportation requirements. Thus, special regulations (S) are formed, which concern only certain dangerous substances with the similar parameters. There are 13 types


304

Sj Sjx Gj G N C

Cla

sses

of d

ange

rous

m

ater

ials

x po

sitio

ns o

f dan

gero

us

mat

eria

ls in

side

of t

he sa

me

j cl

ass

Gen

eral

tran

spor

tatio

n re

gula

tions

insi

de o

f j c

lass

Gen

eral

tran

spor

tatio

n re

gula

tions

of s

ever

al o

r all-

dang

erou

s sub

stan

ces’

cl

asse

s

Com

mon

tech

nolo

gica

l re

gula

tions

(con

stan

ts,

para

met

ers,

units

of m

easu

re,

etc.

)

Dan

gero

us su

bsta

nces

’ cla

ss

char

acte

ristic

s

of such different dangerous substances, i.e. Sj, where 1 ≤ j ≤ 13. It is because at the present moment international dangerous freight transportation rules contain 13 different dangerous substances’ classes.

The following general regulations (G), are regulations valid for all dangerous substances’ classes. These are requirements for package, vehicles, marking of materials and vehicles, etc. Besides, separate dangerous substances’ class of special regulations S, is classified by certain x positions, i.e. Sj

x. Dangerous substances of the same class and position often have almost the same transportation regulations. Usually only one or couple of regulations differs.

Therefore it is possible to classify all regulations into such open regulations lists (Fig.1):

Fig.1. Scheme of open regulations lists The contents of all regulations meant above was explained before or are clear from the list’s

comments. Only C list requires special attention. It has the following characteristics: • Closed or opened class. Closed means that, according international rules the transportation of

substance, which is not in the list, is restricted and special transportation should be organized. If class is opened and there is no substance’s name in the list, the substance considers being not dangerous.

• Regulations that allow or restrict transportation of different classes together.

Symbols, described before:

Sj, Sjx, Gj, G, N, C

mean names of the lists, and their regulations, inside of each list, have corresponding natural numbers’ coding: 1,2,3,… .

In each list, next to each number there are texts T, which mean undividable transportation regulation.

To make things simple, all texts of regulations are marked with T letter. Still it is necessary to remember, that T texts irrespectively of similar marking differ one from another, i.e. in the special and general regulations’ lists there should be no same texts. In practice, texts of special lists’ regulations for different classes can be alike and sometimes even similar. In this case, noticed similarities are transferred into G or N lists.

At the beginning of this article it was meant that codes of dangerous substances or their compounds are noted by i letter, which has the following interval 0001≤ i ≤ 9999.

Therefore it is necessary to divide all i codes according their dependence on different classes:

1 class i codes are → t11 ≤ i ≤ t2

1; 2 class i codes are → t1

2 ≤ i ≤ t22;

………………………………………. (5) 13 class i codes are → t1

13 ≤ i ≤ t213


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Basis structure of data model is transportation regulations’ codes, expressed by natural numbers, written next to the code of certain substance. To sum it all up, for any i we can write the following (Fig.2):

Fig.2. Examples of the lists of dangerous freight regulations

Here natural numbers are chosen inconsequentially. They don’t mean certain codes, but show the way it has to be represented.

List of expression has to join all existing i. If there will appear new dangerous substances or their compounds, expressions have to be made for them, too. 4. ALGORITHM OF FINDING REGULATIONS

For finding any dangerous substance transportation regulation it is enough to indicate it’s i code or it’s description T, showed in fig.2.

Using indicated substance code or description, i is found, which is described by expression (5). The serial numbers of corresponding lists’ regulations are found and are changed by corresponding regulations’ texts T:

i ← Sj (T, T,…,T) Sjx (T,T…,T) Gj (T,T,…,T)

G (T,T,…T) N (T,T,…T) C (T,T,…T). (6)

Names of lists’ codes Sj Sjx Gj G N C are not presented while defining texts’ variety of ith

dangerous freight transportation regulations. It is because they don’t supply any additional information for freight forwarder. An exception is Sj, which means dangerous substance class. For it T is necessary to understand other regulations’ texts easier.

Before making conclusions, it is necessary to note that represented model of dangerous freight transportation regulations doesn’t change or develop the essence of dangerous freight transportation rules. It is in charge of UNO competitive organs able to do this, using possibilities of scientific branches and disciplines. These are chemistry, transportation technology, physics, nucleus theory, etc. The represented model allows freight transporter of any qualification to choose from the variety of transportation regulations necessary ones.

Data set’s structures of dangerous freights’ transportation are separated considering peculiarities of its data-processing technologies, trying to bring stored data closer to its sources and users. It is thought that the main user of informational system is participant of dangerous freights’ transportation.

While sorting data according to different criteria, particular layout of these criteria enables to direct projection of transport technology to a certain direction. The essence of project depends on this direction. When changing the order of layout we get new projects of transport technology. Data can be added, a part of data can be changed and a part of it may be removed. This can be done without changing the essence of formal system.

(Sj (3, 8, 16 ,9)

Sjx (16, 18, 30)

G (8, 17, 20)

N (8, 18, 29, 30)

C (1, 6)

(Sj (51, 10, 19 ,3)

Sjx (11, 24, 40)

G (9, 21, 40)

N (18, 25, 35, 39, 42)

C (2, 8,11)

2213 PARAFORMALDEHYDE

1203 MOTOR SPIRIT or GASOLINE or PETROL


306

5. CONCLUSIONS

1. Created models give possibility to present dangerous freight transportation rules as undividable transportation regulations’ lists, which can be extended, decreased or otherwise modified. This allows leaving dangerous freight transportation system unchanged, when rules are changing. It is enough to change regulations’ lists.

2. The most important requirements, which are used for carriage of one or another load, can be selected using computer according to the system of codes. In this way main regulation models can be made for all the dangerous materials, for all the participants taking part in transportation of dangerous freights.

3. Knowing the name of dangerous material, it is possible to find needed regulations for transportations of this material. References [1] Adomėnas P. G. Structural Modelling of International Regulations of Dangerous Goods Carriage by Road

(ADR), Transport Engineering, 1997, Vol. 2 (15), pp. 4-8. [2] Batarlienė N. Dangerous Goods Transportation Informational System: Collective monograph. In: Transport:

Technologies, Economy, Environment, Health. 2003, pp.103-151. [3] Paulauskas V. Difficulties in Dangerous Goods Transportation via New Independent Countries, Transport

Engineering, Vol. XV, No 5, 2000, pp.16-22. [4] The Official European Agreement Concerning the International Carriage of Dangerous Goods by Road

(ADR). ECE/TRANS/160, Vol. I, II UN-ECE Inland Transport Committee/ECE, New York, Geneva, 2003.


307

ESTIMATION AND PERSPECTIVES OF INFORMATION SYSTEMS OF LITHUANIAN RAILWAY

Aldona Jarasuniene


Transport Research Institute Plytines Str.27, LT-10105, Vilnius-16, Lithuania

E-mail: [email protected] 1. ACTIVITIES OF THE INFORMATION SYSTEMS OF LITHUANIAN RAILWAYS

To ensure a purposeful creation and implementation of new and modernised old systems, there have been chosen priorities in accordance with systems level (information collection, information analysis and decision-making).

Fig. 1 shows that the information systems that are being exploited currently as well as those that are being created for near future use are data collection-oriented. Only having exhaustive information about the company’s activities, it is possible to start implementing information systems that would be beneficial while analysing the information and later modifying the company’s activities as well as making decisions.

Fig. 1. Stages of implementing of information technologies

The development and enlargement of information systems is as follows: – a computer information system for commercial goods for freight station (KPS KIS) is

started to create by goal – to organize best service for customers, to prepare documents precisely and quickly, to control accounting of the working stations.

– a passenger carriage accounting computer information system. It is creating now. It is going to change now workable place reservation and ticket selling systems Ekspress-2 into Ekspress-3.

The Lithuanian Railways officers are frequently participating in EURODAT sessions (session of specialist of railways information technologies).

Lithuanian railways are connected with Western Europe telecommunication nets by means of a roundabout way − through Belarus, Ukraine and Poland. These days the possibilities of the direct telecommunication through Poland are being discussed.

The foreseen trends in the system development and modernization in accordance with PLC “Lithuanian Railways” the field of activities is depicted in Fig. 2.

2004−2006 years 2003−2005 years 2002−2004 years

Distributing of Modelling Acceptance technologies

Solutions solutions of aggregated information

STADIUM OF INFORMATION ANALYSIS

STADIUM OF AGGREGATION INFORMATIONS

1. To implement modelling systems 2. To implement software for decisions to

model and accept 3. To implement information modular

systems 1. To create and to implement juridical

system their groups 2. To implement documents management

systems 3. Using new information technologies to

development for trade

1. To equip dates storage 2. To safeguard information 3. To outfit of computing technique 4. To outfit of software 5. To create global net of transfer dates 6. To organize local nets 7. To create and implement using software

and information systems 8. To organize refresher courses 9. To safeguard interaction of implemented

information systems


308

Fig. 2

The activities of the information systems centre of PLC “Lithuanian Railways” – in 2001 there was established the Information Technologies Centre (here ITC) that was entitled to carry out the following main functions:

• to coordinate the information technologies development policy and strategy on the company’s scale;

• to prepare investment projects meant for information system project works as well as for the acquisition of computer hardware and software;

• to prepare technical requirements and tasks for the creation of informative systems; • to create and implement new information systems and individual tasks, carry out their

authorized monitoring as well as provide assistance; • to employ computer-based information systems and individual tasks; • to employ data-processing as well as local computer nets; • to solve issues related to the need to exchange information with other countries’ railways,

match its exchange content and technology; • to organize computer hardware provision, carry out its monitoring and servicing; • to consult users of computerized systems and tasks; • to represent LR in international organizations working on information issues.

Fig. 3 shows the growth of the company’s investments into information technologies over the last years.

Investition to the information systems of Lithuanian railways

16 000 000 Lt

8 850 000 Lt

4 730 000 Lt

1 160 000 Lt 713 000 Lt0

2000000400000060000008000000

1000000012000000140000001600000018000000

2000 m. 2001 m. 2002 m. 2003 m. 2004 m. planning

Fig. 3

The following information systems and individual programs have been exported: • The accounting system of goods transportation. The data about 80 000 transportation

documents are processed each month. Over 100 various firms of statements of various periodicity are typed, about 1,000 invoices are sent to clients;

• Computerized information system of carriage transition stations; • ISU, Lithuania, Latvia and Estonia’s countries data-base;

Railway infrastructure

Passenger carriage

Goods transportation

Management finance and economics. Statistics

Traffic and safety

Administration Management of capital

INFORMATION SYSTEMS

INFORMATION TECHNOLOGIES


309

• ISU, Lithuania, Latvia and Estonia’s front carriages data-base; • Automated transportation administrative system; • Accounting system of ticket selling for local routes and passengers’ transportation; • Accounting system of wages; • Tasks processing complex of engine-drivers’ itineraries; • Material accounting; • Accounting of long-lasting wealth and that of low value; • Data administration system; • Formation of tax accounting; • Simplified system of customs procedures; • LR Internet website.

While exploiting the above-mentioned systems into computers only by ITC alone a large amount of information is processed. On average about 18-19 mln. signs are entered by ITC monthly. Beside, about 12,000 tickets are sold to passengers every day; about 3,500 statements are formed at stations every day about the movement of freight trains. 2. INTERDEPARTMENTAL COLLABORATION ASSESSMENT

All accounting programs have been transferred from old SM 1600 electronic calculating machines into personal computers. Long lasting and law value wealth accounting as well as that of materials, special wear, wages and working time are carried out by means of that new system. Data for balance sheets are prepared too. The services are provided to many company’s affiliates. There has been created Lithuanian Railways Internet website, i. e. www.litrail.lt.

Additional services are provided for passengers’ − data concerning issued invoices and their appendices about the services that have been provided. Clients as well as various institutions can obtain this data by means of e-mail. 3. A COMMON USE OF IS WITH ABROAD

The computerised information system of station carriages transfer (CIS CST) regulates the accounting of carriages transfer and acceptance through the state’s boundary. This system is closely connected with analogical systems in Latvia, Belarus, Kaliningrad railways and the International Computer Centre in Moscow. As a matter of fact CIS SCT has already been created, however, in accordance with the railways’ agreement. The system is constantly improved in terms of accounting methods transfer stations working technologies, changes associated with modifications in requirements for information exchange between centres. CIS SCT altogether with the elaborated operative computerized information system of goods transformation (OCISGT) would enable us to effectively control other countries’ carriages along our railways, organize their shipment from Lithuania. An analogical system of accounting of containers movement through the state’s boundary is also being developed.

The operative computerised information system of goods transportation (OCISGT). The system is supposed to ensure the collection and accumulation of information about trains formation, movement, arrival and departure as well as about other operations. Up to now. These functions have been performed by the system created in Russia in 1980 and which has been exploited in Riga’s Computing Centre. Having accomplished creating our own OCISGT, its operating costs would decrease twice as much.

An 1996−1999 there was established the computerized information system of station carriages transfer meant for the accounting of carriages transfer and their use among the states. These days on the principle of analogy a containers accounting system is being worked out. In order to exploit these systems there has been set up a new department new local computer nets have been created in Lithuanian railways central administrative centre as well as at carriages transfer stations. These new are interconnected; the centre computer net is connected with Latvia (Riga), Belarus (Minsk), Kaliningrad and Moscow’s Railways Administrations information and computing centres.

The company’s administrative employees have taken a chance to join the global Internet web and make an extensive use of e-mail communication.


310

4. CONCLUSIONS

Having considered PLC “Lithuanian Railways” use of IS, IS current situation and prospects as well as having evaluated interdepartmental and interstate data exchange, one can see that:

• The exploited IS PLS “Lithuanian Railways” are data-collection-oriented IS which are being developed these days are oriented not only towards information collection but also towards its analysis as well as the current activities modifications;

• Having evaluated PLC “Lithuanian Railways” interdepartmental collaboration, it is apparent. That railway passengers are provided with the information concerning the services provided, issued invoices, data is being conveyed by means of e-mail service;

• LR computerized data conveyance net is being development, by means of which the company’s affiliates will be interconnected; Lithuanian Railways network is connected with Latvia, Belarus, Russia’s Railways Administration Information and Computing centres;

• When comparing the company’s current information technologies level with that of Western railways information systems, it is obvious that the former is not quite high, however, in the course of the last “Eurodat” meeting German, Hungarian, Austrian, Latvian, Russian and other countries’ railway information technologies specialists discussed the possibilities of the direct telecommunication between Lithuania and Western Europe railways through Poland. References [1] Transport of Fast Changing Europe. Vers und Resen European des systems de transport by Group

Transport 2002 Plus. Brussels, 2002. 101 p. [2] Jarasuniene A. Formulation of Optimal International Freight Transport Objectives. Vilnius: Technika,

2002. 201 p. (in Lithuanian). [3] Bartzak K. Institution Challenges to the Development and Deployment of ITS Technologies and Services

in Poland. In: Transport Systems Telematics TST’03 III international Conference. Gliwice, 2003, pp. 21-24.

[4] JSC “Sintagma Systems”. Computerized information systems of Keltra. 2004. 100 p.

Computing Mathematics


312

METHOD OF WAITING TIME ON-LINE CONTROL IN COMPUTING SYSTEMS WITH QUEUES

V. Nykolsky1, A. Latkov1, Y. Svirchenkov2

1Transport and Telecommunication Institute

Department of Networks and Computer Technologies Lomonosov Str. 1, Riga, LV 1019, Latvia

E-mail: [email protected], [email protected]

2“SoftComs”Director, Riga, Latvia E-mail:[email protected]

1. INTRODUCTION

Nowadays there is strong trend towards application of computer systems and computer networks to the solution of different industrial and commercial problems. Under real operation conditions there are possible different faults of computer network certain node (delay in communication device, malfunction of one or more processors of computing unit, etc.). This would result in decreased node capacity associated with waiting time increase above the specified limit. Typical solution of the problem of waiting time limitation is processor fail-soft redundancy introduction [1, 2, 3]. In spite of simplicity such design realization is associated with high resource requirements. Contrary to [1, 2, 3] there is different method of the problem solution proposed by this report. The essence of the method is closed system introduction for waiting time on-line control. In this case processor malfunction, connection time variation, and variation of request separation could be interpret as disturbing factors (Disturbance). Hereinafter we will restrict consideration to the disturbance related to connection delay and variation of request separation without the loss in generality. In this case the control system design amounts to finding out the algorithm of on-line evaluation of the current request holding time subject to disturbance compensation and providing specified value of waiting time. On the basis of evaluated holding time there is calculated required number of operating processors. The required number of operating processors is calculated on each step of on-line control. It is expected that all processors of computing unit are identical and are processing incoming requests simultaneously. In such a manner an adaptation of a network node to variation of operation conditions takes place there. The problem solution is based on K(E)-transform of lattice functions [4]. As a result of luck of a priori information on certain disturbances there was expected quasi-determinate variation of disturbance. This generates a need for K(E) transform extension over quasi-determinate lattice functions. With consideration for above mentioned, this report presents development of K(E)- transform method, mathematical model of step-type waiting type control for computer network node, and then the control device design. 2. K(E) – TRANSFORM OF QUASI-DETERMINATE LATTICE FUNCTIONS

It is possible to recognize three representative cases of discrete (lattice) functions K(E) – transform:

a) lattice function is specified by analytic description; b) a function is stochastic; c) a function of incomplete a priori information is quasi-determinate process (e.g. harmonic

oscillation of a priori unknown amplitude, frequency, and phase). The concept of K(E) – transform for discrete functions of known analytic description as well as

for stationary random, sequence is presented in [4]. For the specified discrete functions gi, the K(E) operator represented by a polynomial of E-1 translation symbol, providing K(E)gi = 0 or gi + C0.gi-1 + ... + CN.gi-N-1 = 0; K(E) = 1 + Co.E-1 + ... + CN

.E-N-1, where i is integer, Co, ... CN are some constant coefficients.


313

In such manner gi, – function could be interpreted as a solution of homogeneous difference equation specified by K(E)-transform.

Let us note, that the essence of K(E) – transform in the above mentioned way is prediction of discrete function for step i on the basis of data for previous steps. So, K(E)-transform for discrete stochastic function is evaluated by means of optimal statistical prognosis.

K(E) -transform values for determinate and stationary random disturbances are represented by Tables of [5]. Extracts from those tables are represented in Table 1 and Table 2, which could be used for synthesis of control systems.

Table 1. The Main Correspondence for Determinate Functions

Typical signal K(E)-transform Note

l(i) E - 1 i - integer I (E-l)2 ai E - a a- scalar e-αI E-b b = e-α n e-αI (E - b)2 sin βI E2 - 2⋅c⋅E + 1 с = cos β

Table 2. The Main Correspondence for Stationary Stochastic Functions

Typical signal K(E)-transform Note

e-α/k/ E – b b = e-α e-α/k/(1 + α/k/) E2 – 2⋅b⋅E + b2 k- integer e-α/k/⋅cos (βk) + (α/β)⋅e-α/k/⋅sin (β/k/) E2 – 2⋅b⋅c⋅E + b2 c = cos β

In this report there is represented future development of K(E)-transform for quasi-determinate

lattice functions. Let us consider a class of functions, which may by specified by a solution of corresponding

homogeneous difference equation of undefined initial conditions. Let there be discrete function

gi =g(i, a1, ... am), (1)

where i is integer, as it was before; {aj} – population of a priory unknown parameters. Let us demonstrate possibility to find non-linear operator K(E) for function (1) providing

K(E)gi, = 0, K(E) ≠ 0, gi ≠ 0, (2)

K(E)=Er + C1Er-I + ...+Cr, (3)

where r is integer, Ck are some coefficients, which depend on gi function and its certain translated values. It is possible to find the structure of operator (3) as a result of consideration of initial process generating equations system.

Actually function (1) does comply with the equation

00

=∑=

−

m

jjijqb , (4)

where bj coefficients are uniquely linked with aj [4] parameters. Using translation operator, let us represent equation (4) as follows

000

== −==

− ∑∑ jik

m

jj

m

jjij

k qEbqbE . (5)


314

Assuming in (5) k = 0, 1, ... m, let us make a system of m + 1 equations

0

0

0

0,

0,

............................

0.

m

j i jj

m

j i jj

mm

j i jj

b q

b E q

b E q

−=

−=

−=

⎧=⎪

⎪⎪⎪ =⎪⎨⎪⎪⎪⎪ =⎪⎩

∑

∑

∑

(6)

Evaluating bj from the first m equalities and using it in the last equation we will get the following

K[gi] =

m-i1-ii

m-i1-ii

m-i1-ii

g...gg............g...EgEg

g...gg

mmm EEE

E

This determinant could be rearranged as follows

K[gi] =

i1-mimi

1m-ii1i

m-i1-ii

g...gg............

g...ggg...gg

++

++ (7)

The system (6) has non-trivial solution if determinant (7) is equal to zero only. After opening this determinant we will get equation (2). The desired operator (3) is evident from equation (2). Let us illustrate the technique of K(E) - transform for quasi-determinate lattice functions by an example.

Taking gi = D exp (α1) , where D and a parameters are undefined, and using linear K(E) -transform we will find:

gi - eαgi-1 = 0.

To eliminate exp (α) coefficient let us make the system of two operator equations

0 01

1

0,

0.

ai i

ai i

E g e E g

Eg e Eg−

−

⎧ − =⎪⎨

− =⎪⎩

Let us replace this system with the system of recurrent equations

1

1

0,

0.

ai i

ai i

g e g

g e g−

+

⎧ − =⎪⎨

− =⎪⎩

In accordance with (7) it follows hereupon

K[gi]= -1

1

i i

i i

g gg g+


315

Having opened this determinant we will get the following

K(E)=E – Ci, Ci=gi/gi-1. (8)

It is obvious from (2) and (8) that the basis of K(E)-transform for this case makes non-linear (adaptive) g, extrapolation for one step and it is in use later. 3. MATHEMATICAL MODEL OF CONTROL SYSTEM FOR COMPUTER

NETWORK NODE

Let on input of a computer system node there is Poisson's request flow of A level. In this case there is true for any i integer

wi+1 = wi +Θi – τi + si, (9)

where wi is actual waiting time for request i which is considered as controlled parameter; r, is separation between arrival moments of request / and (i + 1), si is holding time of request i, Θi is communication delay. We will consider Θi, and τi as disturbances. It is possible to consider the process of waiting time control as multi-stage process repeating from one request to another. We will call the step each stage of this process. Conditionally we may consider the current step as step /. To provide the best realization of wi

0 specified waiting time it is necessary to compensate Θi, and τi disturbances. Using the concept of translation operator, we could rearrange the equation (9) in symbol form

( )iiii sE

w +−Θ−

= τ1

1. (10)

Hence it follows that control subject operator is Wo(E) = Ro(E) / Qo(E) - 1/(E - 1). Block diagram of the system under consideration is presented by the Figure, where is in use the

following designation: Wy = Ry(E) / Qy(E) is operator of control device (the on-line control unit); Wτ(E) is operator of τi disturbance control channel; wi

0 and wi, are discrete functions defining specified and actual waiting time for step i (in stabilization mode wi

0= const.) respectfully. The task is to find such Wy(E) and Wk(E) operators which provide:

1) finite duration of transient system movement; 2) zero steady error of specified wi

0 value realization; and 3) Θi and τi, disturbance compensation in stationary mode.

Figure 1. Block diagram of the waiting time control system

4. DESIGN METHOD OF WAITING TIME CONTROL ALGORITHM

In accordance with K(E)-transform method the system design may be broken down to three stages: On the first stage there is defined the symbolic transfer function of the control device


316

.)()(

)(1

)(1)(

ENEM

EKEKEWy

Θ

= (11)

To provide specified wi0 value realisation on the output of the system there is introduced 1/K(E) factor

in Wy(E) at this point. In this case K(E) operator is K(E) -transform of analytically specified wi0

function. 1/KΘ(E) factor is included in Wy(E) in aim of Θi disturbance compensation. To provide the system transient process finite duration there is

011

1

011

1

......

)()(

NENENEMEMEMEM

NMEM

qq

q

kk

kk

++++++++

= −−

−−

cofactor included in Wy(E) transform function. The later could be achieved by making equal to zero coefficients of the system characteristic polynomial except for the coefficient of the member of the highest E order [6]. M(E) operator order is defined by the expression k = a + y – 1, where a is total order of K(E) and KΘ operators, у is the order of Qo(E) operator, and q is the order of Ro(E) operator.

On the second stage there is defined the operator of τi, disturbance control channel

,)(

)()()()(

EREAEKEQ

EWy

y ⋅−=

ττ (12)

where Kτ operator is introduced in aim of τi, disturbance compensation. A(E) = E1 factor provides actual realization of Wτ(E) operator. In this case / = т - d, т is the order of Qy(E) operator, d is the order of Kτ(E) operator. The values of K(E)-transform for representative determinate signals and stationary stochastic process with known correlation function are represented by Table 1 and Table 2 respectfully. In case of discrete quasi-determinate signal Kτ(E) could be found from expression (2).

On the third stage there is defined operation algorithm for control function

iiiyi EWyEWwwEWs ττ ⋅⋅+−⋅= )()()()( 0 (13)

After Wy and Wr had been found conversion to recursion relation for si calculation should present no fundamental problems.

In this case the calculation unit capacity on step i is

ii s/1=μ (14)

and the number of required operating processors is

[ ],/ μμ iik = (15)

where μ is capacity of one processor unit, [ ] brackets mean a whole number. In such a manner of K(E)-transform method application for waiting time control there is

necessary to know the nature of disturbances in the system. In case of insufficient a priori information on disturbances the solution of the problem of disturbance compensation is associated with adaptive extrapolation on the basis of self-instruction algorithm described in Part 1.

In conclusion let us formulate the main calculation operations of the control algorithm design: a) evaluation of wi – the current status of the object and comparison with wi

0- specified value; b) dynamics problem solution which is selection of control rale providing Θi, – unmeasured

disturbance compensation in finite time; c) synthesis of auxiliary τi, disturbance control channel; d) calculation of iμ – computing unit capacity and determination of the number of operating

processors for step i of control.


317

5. SUMMARY

1. There had been demonstrated that the problem of reasonable usage of computer network node resources providing specified waiting time of requests may be solved by means of closed on-line control system design using K(E)-transform method.

2. Certain disturbances in the system may be interpret as quasi-determinate functions. In this connection there had been presented K(E)-transform extension over the above mentioned class of functions. The later is natural future development of the concept of design of adaptive invariant systems of discrete control for quasi-determinate signals.

3. There had been demonstrated that procedure of control synthesis could be reduced to an algebraic problem solution. This makes the proposed method highly efficient for actual calculations. References [1] Kleinrock Leonard. Queueing systems. In: Computer applications, Vol.2. 1976. [2] Basharin G.B., Bocharov P.P., Kogan J.A. Analysis of Queues in Computing Networks. Theory and

Calculation Methods. Moscow: Nauka, 1989. (in Russian) [3] Nikolsky V., Latkov A., Svirchenko Y. Demand Output Regularization in the Queuing System G/G/1/∞. In:

Proceeding of the International Conference “Modern Mathematical Methods of Analysis and Optimization of the Communication Networks” BSU, GSU. 23-25 September. Gomel, Belarus, 2003. 5 p.

[4] Nickolsky V.A., Sevastyanov N.P. K(E)-Form Grating Functions in Discrete System Research Problem. Moscow: Nauka, 1973. (in Russian)

[5] Nickolsky V.A., Sevastyanov N.P. Method of Filtration for Discrete Systems on the Basis of K(E)- transform: Transactions of 5-th Conference "Invariance Theory and Applications". Kiev: Naukova Dumka, 1979. (in Russian)

Development of Transport Logistics in the Baltic States


319

INTERFACES BETWEEN LOGISTICS CENTRES AND LITHUANIA ECONOMICAL DEVELOPMENT

Ramunas Palsaitis, Gintautas Labanauskas

Vilnius Gediminas Technical University Department of Transport Management

Plytines 27, Vilnius-16, LT-10105, Lithuania. Ph: (+370)-8-5-2744776, Fax: (+370)-8-5-2745059. E-mail: [email protected]; [email protected]

1. CONCEPTUAL CONSIDERATIONS

In order to promote Lithuania’s position that is like an East Baltic key player in East-West and South-North cargo transportation the establishment of the regional logistic centres in the biggest towns is envisaged. They must be located near the international transport corridors and will promote intermodal cargo transportation and will benefit Lithuania from the large amount of traffic currently transiting country, by offering (value-added) services to transport operators and cargo owners. 2. BENEFITS OF LOGISTICS CENTRES AND INTERMODAL TRANSPORT

The sea, inland waterways, rail, road and air transport modes are the business tools to move the cargo from the place of origin to the destination. The transport modes require loading and unloading areas-ports, different size and purpose logistics centres and cargo terminals − where the units will be handled.

One of the main objectives of the long term transport development programme is to develop a framework for an optimal integration of different modes of transport in the regional logistics centres so as to enable an efficient and cost-effective use of the transport system through seamless, customer-oriented door-to-door services, favouring competition between transport operators and cargo owners [1].

Transport and logistics is not oriented to the forcing of a specific modal split but rather for improving the connections between all modes of transport and integrating them into a single system providing optimal use of rail, road and short sea transport in order to meet modern logistics requirements for door-to-door deliveries [2−4].

Regional logistics centres in Lithuania must find its market place among the conventional international longer distance railway and water transport and the local shorter distance transport market that is ultimately suited for road transport. Shipments that depend strongly on early and/or timely delivery (time-sensitive, high value goods) in general favour road transport, whereas shipments requiring primarily the lowest possible transport costs (cost-sensitive, large quantities of lower value goods) can generally be well-served by the rail or maritime transport. The advantages of the rail and maritime transport (relatively low costs, high capacity, safety, energy efficiency and low environmental pollution) are combined in the regional logistic centres with road transport (high flexibility, speed, organisational simplicity of door-to-door transport).

The organisational simplicity for the shipper of goods, once the various organisations involved in the regional logistics centres have properly organised and co-ordinated their activities, has been the main driving force for the creation of the logistics centres and growth of intermodal transport.

Both, for the supplier and user of regional logistics centres services and of intermodal transport, and for the society as a whole, the development of logistics centres and intermodal transport has proven to offer substantial benefits, particularly because of its (relative) quality or the relative merits of the (competing) transport modes is constantly developing in an operating environment subject to continuous change, such as increasing congestion on the road network, or the introduction of new pricing policies and/or regulations.


320

Logistics centres and transport is an integral part of most economic activities. Therefore, adequate logistics services provision is a pre-requisite for sound economic development. When traffic volumes are increasing to the point that congestion arises, it is the greatest importance to ensure the accessibility of the major economic centres. This is possible only when there are alternatives for the congested transport system; regional logistics centres and intermodal transport is such an alternative. It can offer benefits to all parties involved (the so-called stakeholders).

The stakeholders are the shippers of goods, the intermodal transport operators, possible intermediaries, and public authorities as well.

All parties involved in transportation can expect to benefit from the development of logistics centres. It will contribute to a sustainable growth of transport capacity, as has happened in European Union countries during the last two decades. Intermodal transport is strongly supported by policy makers especially because of its socio-economic benefits for society as a whole. In most cases external costs of the different transport systems (particularly those caused by the road sector) are not accounted for in the direct costs for the user. Users of transport systems base their choice of preferred mode of transport on direct costs only. Intermodal transport will be preferred only when it is cheaper than the alternatives, while its level of service is higher or acceptable.

It would be too optimistic to assume that the regional logistics centres in Vilnius, Kaunas and Klaipeda could attract potential handling volumes to a maximum extent. When considering the effective cargo volumes that can be attracted to the regional logistics centres the following aspects have to be taken into account:

• Much depends on the origin and destination of the cargo. Cargoes originating in Lithuania are most likely not effective business for the logistics centres since the delivery distance may be too short to justify additional handling procedures.

• Part of the existing traffic is the result of an optimisation process. Some transport operators have already established their own cargo distribution or logistics centres and facilities to handle their transport fleet. These volumes are difficult to detract from the existing routings, since not so much the owner of the cargo but the transport operators have to be convinced to abandon existing structures and move their business into the regional logistics centres located in Vilnius, Kaunas and Klaipeda. In this context especially the large international trading companies stevedoring and freight-forwarding firms have proven to be very reluctant to use the services of regional logistic centres since they usually control large cargo volumes justifying the establishment of their own (road) cargo distribution centres.

• Another aspect relates to the flexibility of road traffic. For example, some commodities may be time sensitive, requiring fast shipment, which can only be guaranteed by trucking the goods. Moreover, the flexibility of the truck enables the cargo owner or transport operator to change dispositions/routings on very short notice, even when the cargo is already on the road.

• Tariffs and freight rates play an important role when deciding on the routing of cargo. It can be assumed that there will always be some cargo groups, which potentially can be handled in the regional logistics centre, but due to an unfavourable tariff or pricing structure will by-pass the logistics centres. For example, a trucking company engaged in unbalanced traffic may be willing to offer dumping rates for return freight, which normally would have been shipped by rail through the logistics centre. Altogether, the above-mentioned aspects significantly limit the share of cargo volumes that can be attracted to the regional logistics centres in Vilnius, Kaunas and Klaipeda.

It will strengthen the competitiveness of the Lithuania for the serving the international transit cargo flows. Lithuania position allows easy international access to areas of major industry and trade centres with all kinds of transport modes. By establishment three logistics centres in Lithuania it can be implemented and explored the entire intermodal transport network in the region. It will increase the efficiency of transport infrastructure, which will contribute to optimisation to the cargo flows distribution as West−East same as North–South directions. Regional Logistic Centres will fulfil the logistical needs and requirements of international and local transport companies on worldwide basis. The logistical solutions that will be created in the centres will make considerable improvements to eliminate logistics and transport bottlenecks and make it attractive the location for many new enterprises. Each of the logistics centres can become a centre of economic activity, with an integrated regional logistics for transport supply and demand potential for competitive business and markets.


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The initiative related to the development of a logistics centres network in Lithuania can contribute to the following:

• develop regional business service qualities and increasing the competitiveness of the Lithuania, strengthening inter-regional co-operation and exchanges on concrete projects linked to business logistics;

• build trust and confidence among people in the Lithuania: trust in fact reduces transaction costs and reduces;

• risks association with innovation. Cultural exchange is also an effective way to build trust and confidence across diverse regions and nations and joint marketing initiatives can be pursued (through website, networking, business and trade, centres of knowledge and innovation);

• a better educated population: growth sectors and industries demand a highly skilled and educated work force which this project can encourage through co-operation with business centres, university, etc. Specifically software development can be developed, especially for the logistics sector. An atmosphere of “lifelong learning” is important to allow communities and firms to develop the critical mass of knowledge and skills needed to supply the new knowledge-based economy;

• integrate the Lithuania transport infrastructure and corridors with the main European Transport Corridors, increasing quality of transport services;

• contribute to concentrate through the creation of a logistic centres in Klaipeda, Kaunas and Vilnius long distance and international intermodal freight flows to a biggest transport terminals and logistics centres in Europe, establishing logistics networks and improving accessibility to the customers by adding missing links and expelling bottlenecks;

• develop competitive conditions for sustainable international cargo transport and transport solutions that may attract customers in competition with other alternatives, characterising the logistics centres as sustainable in economic, ecological and social terms;

• develop improved and co-ordinated intermodal travel service on small scale and local as well as on regional and interregional levels;

• co-operate across sectors to develop a corridor planning policy comprising land use, transport and natural protection policies, as well as co-ordinated planning procedures that integrate spatial and transport sector planning process. The common procedures may include joint efforts related to strategic assessment of various types of impacts, open access to information and co-ordinated decision making processes;

• contribute to develop environmental and social criteria to guide the spatial and transport sector planning related to the expected increase of international freight traffic along the main corridors. 3. CONCLUSIONS AND RECOMMENDATIONS

1. It is identified that the creation regional logistics centres in Lithuania is one of the main measures of improvement for the business and transport-related infrastructure in the country.

2. Regional logistics centres will be the first public Logistics Centres in Lithuania established under the contemporary requirements and will provide the needed co-operation with big trading companies and other logistics centres in and outside Europe.

3. Transport Corridors No I and No IX must be very important for a Logistics Centres in Lithuania will have significant impact on the business linked as to the separate regions and to the whole country.

4. The benefits deriving from an increase of international transit traffic will be also related to the complementary and boosting activities of logistics services associated with the development of logistics centres network in Lithuania.

5. The Logistic Centres in Vilnius, Kaunas and Klaipeda must be created and run in coherence with the most logistically, commercially and environmentally efficient logistics centres in Europe and for such reasons it must comply with European standards and quality performance to provide the framework for commercial and sustainable transport solutions.


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References [1] Palsaitis R. Logistics in Lithuania. Nordic–Baltic Transport Research Conference: Proceedings of the

Conference, 13–14 April 2000, Riga, Latvia, Vol. 1. ISBN 9984-668-13-4. [2] Palsaitis R., Bazaras D. Multimodal Approach to the International Transit Transport, Transport, 2003, Vol.

XVIII, No 6, pp. 248-254. (Vilnius: Technika) [3] Palšaitis, R. Tranzitinis transportas: įtaka eismo intensyvumui ir šalies ekonomikos plėtrai. In: Transportas:

technologijos, ekonomika, aplinka, sveikata: Straipsnis kolektyvinėje monografijoje. Vilnius: Technika. 2003, pp. 152-205.

[4] Burkovskis R., Palsaitis R. Interoperability of the Klaipeda Sea Port and Railway Transport, Transport, 2002, Vol. XVIII, No 2, pp. 71-76. (Vilnius: Technika)


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THE DEVELOPMENT AND PERSPECTIVES OF LOGISTICS CENTRES IN LITHUANIA

Ieva Meidute


Plytines Str.27, Vilnius, Lt-2016, Lithuania E-mail: [email protected]

1. INTRODUCTION

Logistics centre (LC) is a centre to all companies that participate in activities related to transport and logistics in the broadest meaning. LC provides the collective equipment needed to develop these activities and has common services for the companies installed there. Together with the values of location and centrality, Logistics centre provides quality service and effective selection of the most efficient means of transportation due to its truly multi-modal transport possibilities. LC offers real flexibility to adapt to companies needs as well as the development of specialized services with shared costs in a favourable setting for business activity and with the support of the large investment made in infrastructures [6].

Currently, the Logistics centre (LC sometimes called freight village) is realized as an “integrator” of various transport modes, able to promote intermodal transport. The Logistics centre is mainly an intermodal terminal, which is the primary component of the intermodal transport chain, constituting the node where the transhipment of goods from one mode to the other takes place. There is a consensus in definitions that intermodal transport constitutes a transport process in which at least two of the following conditions are fulfilled:

Two or more different transport modes (lorry, train, barge, ship, planes) are deployed. The goods remain in one and the same transport load unit for the entire journey. Due to their nature of operations, they provide integration at a local or interregional level,

depending on the modes served and the purposes conformed by the type of freight handled. Local integration of intermodal transport differs between maritime regions and densely

populated inland and/or sea regions. Maritime terminal regions are interfaces between container vessel operation on one side and inland modes such, as mainly road and rail [3,7]. On the other hand, the Logistics centre organization is interrelated to intermodal transport chain structure, and especially to the types of markets served, as well as transport modes and respective volumes.

In any case a Logistics centre is part of an integrated transport chain that the shipper (customer of the LC) develops and operates and as such it comprises terminals and rail/maritime transport segments as well as the initial and final segments done in most (if not all) cases by road transport [4]

However, the potential customer of LC, evaluate whether such integrated transport chain produces cost savings, enhances reliability, decreases transit times and improves quality. Therefore, the customer is the real decision maker for the operators and the others are merely executing the orders.

Hence, the concept of Logistics centre is developed to offer “common” services to various transport and logistics companies located within its site, as well as to other external users. Transport and logistics companies can take advantage from the common infrastructure, equipment and services, without proceeding to heavy and risky investments if they had to choose the “individual” use. The latter requires that they develop and use a freight centre/village for only their own products, not accepting third parties, and thus exhibiting low or possibly unattainable positive returns. Thus, modern Logistics centre must be perceived as commercial enterprises offering comprehensive transport services to companies rather than as simple infrastructure projects facilitating the single companies’ location.


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2. THE POSSIBLE CATEGORIZATION OF A LOGISTICS CENTRE

Despite the widespread use of the term logistics centre there seems to be, to some extent, great variation in the definition of the term. This is partly an outcome of the evolution process and new types of centres that have been developed in recent years, some of these centres may have characteristics, which do not always correspond to all typical features of what has been understood as a logistics centre. Partly the variation is a result of the fact that, by absolute terms, a logistics centre is very difficult to define [5]. There are useful and detailed definitions for certain types of logistics centres describing their functions, but the creation of an overall definition of a logistics centre has proved to be problematic. Therefore, it is common that instead of using a general definition we rather describe different types of logistics centres.

From a functional point of view, logistics centres can be defined simply as concentration points of logistics flows and operations at any scope; a logistics centre is a node that concentrates traffic flows. In broader terms, a logistics centre can be defined as a centre in a particular area, within which various operators and companies on commercial basis carry out all activities relating to transport, logistics and distribution. However, the geographical scope of, for instance, actions and the internal uniformity of a centre are features that divide logistics centres into various types making general definitions problematic. The geographical dimension of a logistics centre can be anything between local and global. Internal uniformity of a logistics centre has two extremities: a concrete logistics centre, which is very coherent and operates in a same physical space, and a virtual logistics centre that consists of several logistics service providers and their facilities in a region. A categorization of a logistics centre can be made in numerous ways. Typically, three basic types are as follows:

• Concrete (physical) • Virtual • Network (sometimes also referred to as regional).

A concrete logistics centre may be operated and owned by several logistics service providers or just by one. For example, some companies in the field of logistics, such as land transport companies and forwarders, quite often have their own distribution centres referred to as logistics centres. These centres serve the needs and transmit flows of a single company and are also owned by and only by a single company. Multiple companies providing a wide range of logistics and value added services to their customers operate some of the concrete centres. The operators can either be owners or tenants of buildings and facilities.

A company operating a concrete logistics centre might play a different role in the delivery chain of its customers. Only a minor part of companies offering logistics services take care of all logistics activities of their customers. Nonetheless, customers buy willingly services they need from the specialized service companies. For this reasons it is an advantage to a logistics centre to be able to provide a wide range of specialized services within the same centre. A concrete logistics centre is usually a company that clearly practices its own business activities, and whose activities support the needs of the largest logistics service provider in the logistics centre. A concrete logistics centre can also be equipped with all public facilities needed to carry out the above-mentioned operations. If possible, it should include public services for the staff and equipment for the users. Usually a concrete centre serves as a multimodal centre linking together different transport modes.

A virtual logistics centre is usually a certain type of rainbow organization, which can support its member organizations in marketing, for example, but does not participate actively in actual logistics operations. Where the legal status of a concrete logistics centre is typically a company, a looser organizational body such as an association may manage a virtual logistics centre, or it can even operate on a project base.

Along with the two perhaps most common types of logistics centres the third type of a centre can be specified: a network. A network is an entity of several logistics centres or service companies. A network logistics centre supposes relatively effective co-operation between several private companies, and possibly several individual logistics or distribution centres, which might be located within a larger geographical area (town, city, group of cities, region etc.). These companies seek mainly synergy benefits through co-operation. A network promotes services of all its members, not only of a single physical centre. A network is usually formally less organized than a concrete centre in terms of rules, and organizational and legal status. Sometimes network has no company to manage its


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activities but only a loose co-operational body. Virtual centres sometimes share similar characteristics to networks, which is the case in Finland, for example.

The main differences between concrete, virtual and network logistics centres are sometimes measured by the internal uniformity (referring to organizational mode, aims, facilities, role of different partners etc.). From that perspective, concrete and virtual logistics centres are seen as extremities whereas network is positioned between them. A virtual centre is considered a loose co-operational organization between companies that mostly promotes and markets their services. A network is characterized by stronger links and modes of co-operation between companies. Companies provide their services through their own facilities but seek for synergy benefits through close co-operation. A concrete centre has its own operational facility (infrastructure) and is most often a private limited company.

The difference between a virtual logistics centre and a network is, therefore, not a portal or services provided through the Internet but the depth of co-operation and the mode of the centre’s organization.

Another perspective is also to understand the three types of logistics centres as development stages of a single centre. During a certain period of time a logistics centre may develop from the looser virtual mode first to a network and then finally to a concrete centre.

Distinguishing between various types of logistics centres in practice is not unproblematic. Many centres share similar features with each other, thus, making a clear definition difficult. Many centres also have similarities with organizations that are not used to being referred to as logistics centres. For example, networks and virtual logistics centres tend to share many similar characteristics with purely regional marketing and development organizations promoting logistics advantages of a region.

At the moment we don’t have the Logistics centres (nor physical, nor virtual, nor network) in Lithuania, because the Logistics centre can not develop easily, it requires a lot of effort. But we have an idea to create the several physical Logistics centres, which will be located in Vilnius, Klaipeda, Kaunas and Panevezys. 3. THE STRATEGIC ESTABLISHMENT PLACE OF LOGISTICS CENTRE IN

LITHUANIA

Usually the Logistics centres are focused on international markets. On one hand they aim at collecting international transport flows and gain economically from the increased logistics activities in the region. On the other hand, most of the logistics centres analysed here share the strategy of attracting new businesses to the region by strengthening the logistics services and the logistics sector in general in the region.

Bearing this in mind, it is no surprise why logistics centres tends to be located along the major international transport corridors. Transport volumes are the largest along these corridors and the location in the interchange of different transport modes/corridors is the most favourable to a logistics centres.

3.1. Klaipeda Logistics Centre

Klaipeda region has well-developed transport links. It is the only county on the coast of

Lithuania providing a sea connection to the whole country. Major sea routes extensive rail and road networks and also crude oil product pipelines serves the area. Transport infrastructure offers competitive advantage for the logistics centres because of the developed combination of provided three modes. Being an important transit node of the transport corridor IX B, Klaipeda has good road and railway connection with the major industrial cities, with Belarus, CIS and CEE countries. Considerable numbers of regular ship lines are operating between the ice-free Klaipeda seaport and the seaports of Baltic Sea region, Western Europe, America and through Trans Siberian Main Line to South-East Asia. Intensive transit cargo flows between East-West trading partners through the Klaipeda seaport make the region attractive for domestic and foreign investments. The nearest airport is the Palanga airport locating North to Klaipeda. Strengths of Klaipeda are the location near the sea and in the transport corridor IX branch B and also the Palanga airport is located near Klaipeda [1].


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In the Klaipeda regional development plan logistics centre is highlighted as one of the first priorities. Feasibility studies have been made, and analysis of special conditions and business opportunities for new economic infrastructure and services in relation to the logistics centre as well as land plot analysis resulting in a suitable land area for the logistics centre shall be carried out. Technical assistance to development of the legal agreement forms and activities for participation in the logistics centre will be provided. Marketing and awareness raising activities shall be carried out. Financial commitments for the investments in the logistics centre shall be established. Agreements with transport and logistics companies, service providers and other users of the centre shall be concluded.

The evaluation procedure has shown, that the best qualification for the Klaipeda logistics centre is the location in the south of Klaipeda city. The location in the south of Klaipeda was considered optimal for future development of this state as a part of transport corridor IX B.

3.2. Kaunas Logistics Centre

The Kaunas County is located in the central Lithuania on the transport corridor I, on the

crossroads of the Via Baltica route and the transport corridor IX branches B and D. It is one of the largest industrial centres where in the intersection of I and IX international transport corridors cargo flows from North to South and East to West meet. The region of Kaunas makes a great contribution to the total economy of the country. The city of Kaunas is the region's centre locating the confluence of the two largest navigable rivers of Lithuania. The river port is located in Kaunas. It is a TEN port and a TEN waterway goes along the river of Nemunas to Klaipeda. There is also a busy airport in Kaunas.

The Kaunas Logistics Centre is in a very early stage of development, too. Depending on the traffic volume and commodities, the plan to establish the Kaunas Logistics Centre should be carried out in several phases. It should be put into operation by the completion of the planned new European standard gauge railway line from the Polish border to Kaunas. This would mean that the gauge change from the European Standard Gauge to the existing wide gauge and vice versa would be made in Kaunas [1].

The alternative locations for the Kaunas Logistics Centre have been evaluated according to the following key characteristics:

• Location in relation to the Polish frontier and to Kaunas; • Size of the proposed area; distances to major and minor settlements; • Topography, present land-use and surface drainage; • Service infrastructure; • Location in relation to the proposed European standard-gauge railway, to the existing wide-

gauge railway and to the present or improved Via Baltica and the potential for further site expansion.

The probable location of the centre will be Mauruciai. Nevertheless, the discussions about the location of Kaunas logistics centre are still going on. 3.3. Vilnius Logistics Centre

Vilnius is located at the South East side of the country and it lies at the crossroads of four important main roads. The country is located in the transport corridor IX at the branch B. The road traffic is heaviest to the direction of Klaipeda. In Vilnius is located the largest airport in Lithuania which is concentrated mainly to the international traffic. The distance between Vilnius and the border of Belarus is only 30 kilometres. There are seven railway stations in the city of Vilnius and international trains leaves Vilnius to several directions. The nearest seaport is Klaipeda, which is located 319 kilometres west of Vilnius [1].

Vilnius, the capital of Lithuania, is one of the most active business centres of the country. Positive changes have been observed in the economy of the city: the services sector has shown fast growth. During the recent decade, the proportion of the population working in the services industry increased to 68% of the total working population in the city. The industrial sector of Vilnius has been modernized. The rapid economic growth of Vilnius is caused mainly by foreign direct investment.

The Vilnius Logistics Centre, which would be located between Vilnius and the Belarus boarder, would solve the traffic congestions in Vilnius and in the region surrounding the city. On the other hand, Vilnius opens huge possibilities for a logistics centre, as it is one of the most active business centres of the country.


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3.4. Panevezys Logistics Centre Panevezys is situated half way from Vilnius to Riga. It is located on the motorway Via Baltica

on the Pan-European transport corridor number I and on the railway branch Panevezys-Radviliskis leading to the Pan-European rail transport corridor number IX B.

Panevezys, the fifth biggest city in Lithuania with 119 000 inhabitants, is situated halfway from Vilnius to Riga. The city has favourable potential for a strategic logistics node in the northeastern part of Lithuania. The priorities of the City of Panevezys, stated in the Development Priorities for 2013, include the development of a logistics centre, strengthening administrative capacities and the development of future-oriented businesses and advanced IT technologies [1]. 4. THE PERSPECTIVES OF LOGISTICS CENTRES IN LITHUANIA

A definition of “Freight Village” ((LC) sometimes called freight village) is as follows: “A freight village is a defined area within which all activities relating to transport, logistics and

the distribution of goods, both for national and international transit, are carried out by various operators. These operators can either be owners or tenants of buildings and facilities (warehouses, break-bulk centres, storage areas, offices, car parks, etc.) that have been built there. Also in order to comply with free competition rules, a freight village must allow access to all companies involved in the activities set out above. A freight village must also be equipped with all the public facilities to carry out the above-mentioned operations. If possible, it should also include public services for the staff and equipment of the users. In order to encourage intermodal transport for the handling of goods, a freight village must preferably be served by a multiplicity of transport modes (road, rail, deep sea, inland waterway, air). Finally, it is imperative that a freight village be run by a single body, either public or private”[6].

Also, as shows the analyses of experience of some Logistics centres, one of the important functions increasing the attraction of the region and boosting its industrial and business activities. This is based on the fact that logistics play a major role in planning the location of any company [5]. Establishment of new companies or relocating existing ones is highly dependent on the general economical situation and the development possibilities of a company. Companies are naturally more eager to invest in new areas at the time when the economical prospects are good. This in turn affects the success of logistics centres. The development of the regional economy can therefore be seen as a planning challenge for logistics centres.

We intend that the Logistics Centres help to develop (infrastructure, business, economical aspects) these areas where it’s be establishment. 5. CONCLUSION

The logistics centres can be defined simply as concentration points of logistics flows and operations at any scope; a logistics centre is a node that concentrates traffic flows. In broader terms, a logistics centre can be defined as a centre in a particular area, within which various operators and companies on commercial basis carry out all activities relating to transport, logistics and distribution.

The geographical dimension of a logistics centre can be anything between local and global. Internal uniformity of a logistics centre has two extremities: a concrete logistics centre, which is very coherent and operates in a same physical space, and a virtual logistics centre that consists of several logistics service providers and their facilities in a region. A categorization of a logistics centre can be made in numerous ways. Typically, three basic types are: concrete (physical), virtual, network (sometimes also referred to as regional).

The analysis of development of Logistics Centres shows that these Centres play an important role for the future development of the freight transport and for the economic development of the areas in which they are located. Also the analysis has shown that the logistic synergies developed in the LC are a key factor for the improvement of intermodal transport; the integration of the intermodal terminal into the LC, the proximity of different transport and logistic activities and the services.


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The crucial characteristics for establishment of Logistics Centre with European and regional importances are: location at a TEN corridors, high-class motorway and railway, network cooperation, large span of activities, considerable volume of distribution. References [1] Bentzen K., Hoffmann T., Bentzen L., Nestler S., Nobel T. Best Practice Handbook for Logistics Centres in

the Baltic Sea Region. Association Hoja Fondas, Lithuania, 2003. [2] Guelat J., Florian M., Crainic T. A Multimode Multi-Product Network Assignment Model for Strategic

Planning of Freight Flows, Transportation Science, Vol. 24, 1990, pp. 25-39. [3] IMPULSE, 1998. Transhipment Systems Description and Analysis. Deliverable 5, IMPULSE Research

Project, European Commission, Brussels. [4] IQ, 1998. Quality of Terminals. Deliverable 1, IQ Research Project, European Commission, Brussels. [5] Konings J.W. Integrated Centres for the Transhipment, Storage, Collection, Distribution of Goods,

Transport Policy, Vol.3, No1/2, 1994, pp. 3-11. [6] PROFIT, 2000. The PROFIT Methodology. Deliverable 2, PROFIT Research Project, European

Commission, Brussels. [7] TERMINET, 1997. New Generation Terminal and Terminal Node Concepts in Europe. Deliverable 2,

TERMINET Research Project, European Commission, Brussels.


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ROLE AND PLACE OF LOGISTIC CENTRE IN MODERN CONDITIONS

Alexander Medvedev1, Vladimir Zvonarev2

1 Transport and Telecommunication Institute

Lomonosov Str.1, Riga, LV-1019, Latvia Tel.: +(371)-7100680, Fax: +(371)-7100660, E-mail: [email protected]

2 Research and Training Consultative Centre of Transport and Logistics

Lomonosov Str.1, Riga, LV-1019, Latvia Tel.: +(371)-7100635, E-mail: [email protected]

After joining the European Union truck transport of Latvia have found themselves in a difficult working conditions. Competition with large transport and shipping companies of Europe has become visibly stronger. At that, as it’s clear from data submitted below in Fig. 1, the majority of truck transport companies of Latvia (more than 80% of complete amount) has up to 5 trucks [1]. It means that in the market of the given services small companies are submitted.

Fig. 1. Distribution of truck transport companies of Latvia due to number of trucks (international transportation)

To provide their competitiveness the Latvian truck transport have purchased vehicles meeting

ecological standards, namely EURO-II and EURO-III (see Fig. 2). At that, the majority of truck transport vehicles have been purchased on credit or leasing. After joining the EU transportation costs have decreased distinctly. For example, before joining the average cost of freight from Latvia to the central regions of Germany compiles 1200 – 1500 EURO/trip. At present, it is just 500 – 700 EURO/trip. Costs of carriers (first of all, at the expense of fuel price increase – see Fig. 3) after May 1, 2004 are growing constantly. At that the efficiency of control due to the decrease of delivery terms with the existing system of transport load search is being reduced. Obviously, for the provision of credit and leasing payments carriers are forced to perform transportation at the extremely unprofitable conditions.

67%

16%

10%

5% 2%

до 3 3 - 56 -1011 -20более 20


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Fig. 2. Compliance of vehicles of Latvia to ecology standards (EURO)

Fig. 3. Cost change of diesel fuel in Latvia

Fig. 4. Change of freight intensity in UkraineAt that, similar processes are typical not only for Latvia or other new members of the European Union. Due to the data of the Ukrainian Union of Truck

0%

5%

10%

15%

20%

25%

30%

35%

40%

Without certificate EURO1 EURO2 EURO3

0,3

0,35

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0,45

0,5

30.04.04. 01.08.04. 01.10.04.

Ls/l

0

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trip/mont


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Transport and Logistics [2] after May 1 the intensity of freight has increased also in non-EU states. In Fig. 4, data about change of freight intensity from Ukraine to Germany and Holland is shown.

In relatively stable status the Latvian carriers having own float in amount not less than 50-70% are. But even for such companies in present conditions the problem of the development is complicated. In perspective, accordingly, it’s possible to forecast closing and fusion of many transport companies.

To provide a normal operation of the Latvian carriers it is necessary to create regional logistic control centres with the following basic tasks:

1. Analysis of existing transport flows and on its basis the development of proposals for creation of new transport routes (Eastern direction – Russia and Byelorussia; Western direction – Germany, France; South direction – Italy and new Member States of the EU).

2. Information support and shipping services. 3. Search for large cargo owners for their service on constant base. 4. Control and operative management of transport positioning. 5. Professional training of staff. 6. Legal support and defence. As the experience has shown, the Latvian carriers and shipping agencies in their majority are not

ready to work applying the model of such logistic centre. To our mind, it’s possible to explain as follows:

1. Fear of non-standard decisions. 2. Absence of the experience of perspectives evaluation and work in groups. 3. Weak professional and legal training of carriers. 4. Absence of necessary minimum of financial support of the project. 5. Distrust to potential partners. 6. Absence of financing model of such centres. A significant negative factor is an absence of state institutions support that means the absence of

partnership between state and private initiative in creation and development of logistic centres. The experience of the western companies (Finland, Germany, Denmark) shows that the creation

of such centres is an efficient method of transport development. On the first step, (taking into account the above-mentioned negative factors) in Latvia it’s possible to create such organization structure with the help of unification of small transport and shipping agencies on the basis of treaty companies with opportunity of the further enlargement and interaction in the frames of one logistic space of the Baltic Sea region. References [1] Autopārvadājumi Latvijā. Fakti īsumā. Autotransporta direkcija, 2004. [2] Скорость доставки возросла, Transport weekly, Special Edition, No 41(308), 2004, p. 88.


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CONFERENCE AUTHORS INDEX

Afanasyeva H. 90

Bagdonienė D. 95

Batarliene N. 302

Baublys A. 30

Bazaras D. 287

Bogdevicius M. 232

Bogomolova N. 445

Budinas S. 172

Burkovskis R. 58

Butkevicius J. 55

Butkevičius J. 169, 274

Denisyeva O. 445

Ginevičius R. 133

Gobzemis A. 445

Gode N. 61

Goncharova Ju. 438

Griskeviciene D. 267, 291

Griskevicius A. 267, 291

Griškevičius J. 245

Gusarova L. 75

Guseinov Sh. 471

Išoraitė M. 162

Jarasuniene A. 307

Jonaitis J. 37

Juzenas A. A. 122

Kaklauskas A. 11

Klevecka I. 139

Kopitov R. 362, 383

Krasnitskiy Ju. A. 459

Labanauskas G. 319

Labeyev V. 383

Latkov A. 312

Lazauskas J. 152

Lelis J. 139

Lingaitis L. P. 391

Litnitska I. 378

Litvinenko M. 47

Mamirov Т. 255

Mariūnas M. 245

Mazūra S. 95

Medvedev A. 329

Meidute I. 323

Melihov A. 67

Migilinskas D. 183

Mikalyunas Sh. 391

Morozov D. 465

Mrochko A. 260

Naula T. 18

Nechval K. N. 81, 130, 225

Nechval N. A. 81, 114, 130

Novikovienė D. 145

Nykolsky V. 312, 487

Ojala L. 18

Okruzhnova M. 471

Orlov S. 465

Pabedinskaite А. 355

Palsaitis R. 55, 58, 319

Palšaitis R. 287

Paramonov Yu. M. 215

Pchelkin A. 61

Pechelyunas R. 407

Petkevicius K. 122

Pikūnas A. 280

Podvezko V. 133, 391


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Popov V. 183

Prentkovskiy O. 407

Queiroz C. 18

Raslanas S. 11

Rozite K. 114

Rusakova S. 67

Šarka V. 172

Šarkienė E. 172

Sharkovsky S. 417

Shelkovnikov V. 260, 263

Signeyeva N. 449

Sikerzitski Yu. 260

Simenas A. 291

Sipchenko D. 417

Sivilevičius H. 238

Sivilyavichus H. 397

Svirchenkov Y. 312

Titarenko D. 368

Truskovskiy P. 431

Ustinovičius L. 183

Valiūnas V. 280, 283

Vasermanis E. K. 81, 114, 130

Vestartas A. 283

Vislavičius K. 238

Vyskupaitis A. 169, 274

Wahab M. S. 215

Yatskiv I. 75

Yeremeyev V. 255, 417

Zavadskas E. K. 11

Zilberman M. 449

Zilioniene D. 122

Zinovyev A. 487

Zvonarev V. 329


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CUMULATIVE

INDEX


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TRANSPORT and TELECOMMUNICATION, Volume 6, No 2, 2005

(Abstracts)

M. Shujauddin Wahab, Yu. M. Paramonov. The Influence of Corrosion on Reliability and Inspection Program for Fatigue – Prone Airframe Structures, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 215–224.

This paper is devoted to the discussion and solution for the following problems: Determination of mean value and variance of estimates of parameters of fatigue crack growth model for both the corroded and non-corroded types of specimens: a (0),μ, ln Q and m. Inspection modelling with the use of Monte Carlo method for calculation of probability of fatigue failure as function of inspection number. Determination of the number of inspections required for the limitation of fatigue failure probability. Comparison of the required (for required reliability) is ninsp for corroded and non-corroded cases. Special programs have been developed for necessary calculations. It was confirmed that the influence of corrosion has a great impact on the required number of inspections.

Keywords: fatigue crack growth, corrosion medium, failure probability, inspection program & specified life Konstantin N. Nechval. Stochastic Models of the Fatigue Crack Propagation Process, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 225–231.

To study the fatigue crack growth problems and to emphasize the variability of the growth curves in addition to their average growth trend, four stochastic fatigue crack growth models are presented. These models include the Markov chain model, Yang's power law model, the polynomial model and a probabilistic log-linear fatigue crack growth model with the parameter that varies from unit to unit according to a Weibull (σ,δ), lognormal or normal distribution. Experimental work can be carried out to produce the required fatigue crack growth data, which are then used for verification of the models. It is found that all these models can be used to depict the experimentally obtained fatigue crack growth data with certain degrees of accuracy. However, out of the four models, one is superior to the others concerning a certain data set while the other three models are better for other data sets. As soon as the appropriate stochastic model is established, it can be used for the fatigue reliability prediction of structures made of the tested material.

Keywords: fatigue crack growth, stochastic model, random process, probabilistic analysis Marijonas Bogdevicius. Simulation of Dynamic Processes in Mechanical and Pneumatical System, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 232–237.

The dynamic processes in the drive together with the asynchronous engine, coupling with gas, and mechanical drive are considered in this article. The coupling of this type consists of separate segments, where additional masses are input. There is presented dynamic model of drive pressure wave propagation in gas, interaction of separate coupling bodies and gas in the article. Gas movement in segments is described by the equations of continuity, movement quantity and gas state. This system of equations is solved by the method of characteristics together with the system of equations of asynchronous engine and mechanical drive; the received non-linear equations are solved by Newton method.

Keywords: mechanical and pneumatic system, pressure wave, asynchronous engine, numerical method, simulation

Henrikas Sivilevičius, Kęstutis Vislavičius. Simulation of the Influence of Mineral Materials’ Homogeneity on the Stability of Asphalt Concrete Mixes Grading, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 238–244.

The article analyses the homogeneity problem of asphalt concrete mixture (ACM) used in road pavement. The average values of an ACM lot composition and physical-mechanical parameters shall comply with the requirements of the project and standards. Another important factor is that the amount of components in separate ACM batches influencing on the homogeneity of the lot’s structure and characteristics would fluctuate within the minimum narrow interval. The variation interval of coarse aggregate, fine aggregate and fillers’ amount in ACM and its grading in the lot is influenced by the stability of the materials’ grading used when producing the mixture.

When simulating different variation of mineral materials’ grading mathematically, the scattering of the ACM grading produced of them is simulated. While applying the theoretical principles of the simulation,


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formulas were written and software was developed, which enabled to design ACM from mineral materials of different homogeneity, the quality of which is shown not by one curve of grading but the wholeness of curves laid out on the interval of relevant width.

When changing the grading varying according to the normal distribution of cold imported fillers, reclaimed dust and five hot fractions aggregate of different coarseness, screened in the asphalt concrete mixing plant, the statistical characteristics of ACM composition and components’ quality scattering are obtained. The presented methodology of mathematical simulation also enables to calculate the scattering of all used mineral materials’ grading according to the (set) permitted ACM grading variation interval in the lot.

The mathematical programming method was applied in the proposed methodology; software was developed and the calculated experiment was carried out.

Keywords: asphalt concrete mixture, grading, homogeneity, mathematical simulation, mathematical programming

Mečislovas Mariūnas, Julius Griškevičius. The Research on the Influence of the External Excitation Characteristics on the Dynamic “Man – Wheelchair – Vehicle” System, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 245–253.

Public transportation system often transport disabled individuals seated in wheelchairs, and there must be certain means to safely secure them. In present paper the dynamical behavior of the dynamic “Man – Wheelchair – Vehicle” system under the action of external excitation is analyzed. Main characteristics of the external excitation during the motion of the public transport were determined by experimental measurements of the acceleration. The analysis of the frequency spectrum of the moving vehicle and wheelchair-seated disabled person was performed and coincident resonant frequencies in low range were noted. The dynamical and mathematical models of the disabled person seated in a wheelchair were developed and three possible cases of the dynamic system’s motion were described; they are the steady motion, partial and complete abruption cases. Numerical analysis of the system’s dynamical stability was performed.

Keywords: wheelchair, transportation safety, public transport, external excitation, disabled persons, dynamic system

V. Yeremeyev, Т. Mamirov. Identification of Narrow-Band Discrete Systems, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 255–259.

The new method of recursive systems identification is suggested. The results of super-narrow band filters modelling are shown.

Keywords: narrow-band digital filters, identification, characteristic verification Alexander Mrochko, Yury Sikerzitski, Vladimir Shelkovnikov. Short Wave Communication Lines Efficiency Increase in Civil Aviation, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 260–262.

To raise the efficiency of short wave communication lines in civil aviation it is suggested to use ferric-electrical antennae of zenithal radiation and reception as antennae for aircraft. Some types of these antennae have been considered in the given article. There has been got the expression for an average diagram of the direction of the receiving antenna system in power and with the account of experimentally collected statistic characteristics of signals for short trajectories.

Keywords: ferric-electrical antennae, receiving antenna system, statistic characteristics Vladimir Shelkovnikov. The Analysis of the Receiving Antennae Effectiveness, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 263–265.

Numerically effectiveness of receiving antenna characterizes threshold sensitivity. In the work were obtained the expressions for threshold sensitivity of receiving electrical and ferrite

antennae. Expressions make it possible to compare these antennae between themselves. It is shown that the receiving ferrite antenna on comparing with the electrical antenna is more effective

under the conditions of acting of different interferences, which have, in essence, electrical character. Such interferences include the industrial interferences and those interferences, caused by the reflection from the objects, which are located near the receiving antenna.

Keywords: receiving antenna, effectiveness, threshold sensitivity


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Daiva Griskeviciene, Algirdas Griskevicius. Possibility of Passenger Intermodality in Lithuania, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 267–273.

An analysis of the passenger service market and today situation of passenger long-distance travel in Lithuania shows that the main weakness is as follows – an absence of the organized passenger intermodality in the country. The strengths – county’s favourable geographic position, needs of the international trips, good conditions of road, air and water transport infrastructure – stimulate to improve the quality of passenger conveyance and to organize the intermodal service network. The investigation of different modes of passenger transport shows the possibilities for the cooperation in the integrated service market. Some combination of separate traffic modes exists in the field of combination timetable of regular buses to the train schedule in the regional centres and small towns. Another type of intermodality exists in urban public passenger transport system harmonization. The changers of the demand are going to the development of passenger market. Social-economic possibilities of population are increasing every year. But financial potential of population is arising slowly, so demand for the international passenger transport is lower than in other countries. The best opportunity to implement the intermodal passenger transportation is the organization of good interface with EU level passenger transport network, integration into the international passenger service market.

Keywords: passenger transport, intermodality, long-distance travellers, use of different modes, modal conflicts

J. Butkevičius, A. Vyskupaitis. Development of Passenger Transportation by Lithuanian Sea Transport, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 274–279.

The article covers an analysis of passenger transportation by Lithuanian sea transport and trends of development of this transportation. Furthermore, the analysis of passenger transportation by ferries in the Baltic Sea is given – volumes of transportation, operators, and income sources.

Keywords: sea transport, port, ferry line, passenger transportation A. Pikūnas, V. Valiūnas. End-of-Life Vehicles and Transport Exploitation Materials Development Perspectives in Lithuania, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 280–282.

Lithuania is a transit country, and one of the main bases for transporting the used cars for Russia Federation and Asia countries. Statistics shows us that solely in 2003 year the registration of motor transport vehicles was made for 1 580 476 units, trucks – 156 326. More then 80 000 units of motor transport vehicles are 15 till 20 years old. Such a problem we have here, because those vehicles from 15 till 20 years old are approximately of 1 million units. Old agriculture machinery is not of economy because of rise in prices of diesel fuel. Agricultural implements and machinery will not be long exploited in the future, because it’s not economic and not the way of production exploitation, which makes agriculture production prices up. And all those transport and machinery waste and dismantling of it – Lithuania will have to take care according to the standards of the EU directives.

The manufacturers and consumers for unfit in use automobiles and their exploitation materials has to be stimulated to do recovering and second using. The government has to create preventive steps for the waste avoiding. The financial responsibility for unfit in use transport vehicles has to take on the correct manufacturers, in that way Lithuanian citizens will not have to pay the taxes. The place of dismantling transport vehicles could promote transport waste expenses decreasing and mainly controlling this process on places. The principled scheme of the place of dismantling transport vehicles is created and showed.

Keywords: transport vehicles, waste, exploitation materials, perspectives, treatment, automobiles Valdas Valiūnas, Aurelijus Vestartas. The Impact of Anti-Lock Braking System on Braking Distance of the Vehicle, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 283–286.

In present, various means that enable to avoid a crash are rapidly spreading in vehicles. One of such technologies is anti-lock braking system (ABS). In the present Paper, the importance of the anti-lock braking system and its impact on braking distance of a car on wet asphalt are being analysed. During the tests, the speed of movement, braking distance and brake pedal stressing force of two vehicles (with and without ABS) had been fixed. The importance of using of ABS, its advantages and imperfections are discussed on the base of the results of the said experience.

Keywords: anti-lock braking system, vehicle, braking distance Darius Bazaras, Ramūnas Palšaitis. Logistics Service Development and its Research Aspects, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 287–290.


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After restoration of Lithuania’s independence the industry shifted from a highly structured and regulated industry to an industry operating in market conditions. Global supply chains extended for thousands kilometres. The new thinking about logistics services spread to all logistics suppliers of the companies. It is the significant shift from transaction driven system to continually driven system to all business sectors and for the significant share of third party services providers.

Keywords: logistic, logistics service, third party logistics service, efficiency Daiva Griskeviciene, Algirdas Griskevicius, Albertas Simenas. Forecasting of the Freight Transportation by Lithuanian Railways, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 291–300.

The aim of the article is to analyse evolution of freight transportation by Lithuanian railways as well as market development opportunities, to foresee perspectives of transportation activities and to present forecast of freight transportation up to 2020. Based on the analysis of development indicators of the Lithuanian railway transport sector in 1997-2003, the SWOT analysis was carried out. The most important factors and premises that form a basic foundation for the long-term railway transport strategy were identified. In order to form a perspective, the study was based on macro-economical indicators of the Lithuanian economy, of their evolution and forecasts. Also, external and internal factors having impact on the evolution of freight transportation were analysed; perspective directions were put forward, as well as possible risk factors were identified.

Keywords: railway transport, freight transportation, strategy, forecast Nijole Batarliene. Informational Modelling of the Regulations of the Dangerous Freight Transportation for Database Management Systems, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 302–306.

The coherence of database management systems’ schemes and restructured dangerous freight transportation regulations’ base theoretically and with certain examples is shown in the article. Regulations of dangerous freight transportation are modelled till the indivisible level so that they wouldn’t have any exceptions and references to other regulations. Basis of regulations about transported dangerous freight, their amounts have to be formulated in this way. Transportation of freight and formulation of regulations concerning their conditions in the database have to be separated from conventionality of changing software.

The result of restructure is presented in this article – different types of formal lists of elementary regulations, their creation and changing principles as well as database structure and algorithm for database.

Keywords: dangerous freight, transportation regulations, management system, database Aldona Jarasuniene. Estimation and Perspectives of Information Systems of Lithuanian Railway, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 307–310.

The activities of the Information systems (IS) of Lithuanian Railway, the fields of activities and function of Lithuanian railway and investments to the information system are showed in figures in the article.

The stages of implementing information technologies are showed; the interdepartmental collaboration assessment and common use of IS with other countries are showed as well.

Keywords: information system of Lithuanian railway, transport means, technical characteristics, technological dates, and implemented information systems

V. Nykolsky, A. Latkov, Y. Svirchenkov. Method of Waiting Time On-Line Control in Computing Systems with Queues, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 312–317.

There is covered a method of request waiting time on-line control for a node of computer network comprising of general memory of limited capacity and multiprocessor computing unit. As a result of synthesis there had been designed an algorithm of current request holding time calculation taking onto account variation of the node operating conditions and requirements on allowable waiting time of requests. On the basis of the holding time evaluation there is calculated the number of required processors for each step of on-line control.

Keywords: waiting time method, online control, algorithm Ramunas Palsaitis, Gintautas Labanauskas. Interfaces between Logistics Centres and Lithuania Economical Development, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 319–322.


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It is identified that the creation of regional logistics centres in Lithuania will have positive impact to the economical development of the country. Logistics centres in Kaunas, Vilnius and Klaipeda will be established under the contemporary requirements and will provide the needed co-operation with big trading companies and other logistics centres in and outside Europe. Existing transport corridors will have significant impact on the business linked as to the separate regions and to the whole country. An increase of international transit traffic will be also related to the complementary and boosting activities of logistic services associated with the development of logistics centres network in Lithuania.

Keywords: logistics centres, transport, costs, economics, development, cargo Ieva Meidute. The Development and Perspectives of Logistics Centres in Lithuania, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 323–328.

The analysis of development of Logistics Centres (LC) shows that these Centres play an important role for the future development of the freight transport and for the economic development of the areas in which they are located. Also the analysis has shown that the logistic synergies developed in the LC are a key factor for the improvement of intermodal transport; the integration of the intermodal terminal into the LC, the proximity of different transport and logistic activities and the services.

But in the countries where to create Logistic Centres is planned, there is not enough of available experience. These countries, including Lithuania, must evaluate the main characteristics for establishment of LC. These characteristics for establishment of Logistics Centres with European and regional importance are: location at a TEN corridor, high class motorway and railway, large span of activities, considerable volume of distribution, network cooperation, cooperation between centres, membership of Euro platforms and organization in a legal body to ensure a commercial, open and neutral Logistics Centre.

Keywords: logistics centres, transport, terminal, development Alexander Medvedev, Vladimir Zvonarev. Role and Place of Logistic Centre in Modern Conditions, TRANSPORT and TELECOMMUNICATION, Vol. 6, No 2, 2005, pp. 329–331.

The article deals with truck transport companies’ development and problems in Latvia that have arisen after joining the European Union.

Keywords: truck, transport, company, European Union


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TRANSPORT and TELECOMMUNICATION, 6.sējums, Nr.2, 2005

(Anotācijas)

M. Shujauddin Wahab, Yu. M. Paramonov. Korozijas ietekme uz drošību un pārbaudes programma lidmašīnu korpusiem ar nodiluma pazīmēm, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 215.–224. lpp.

Vidējās vērtības noteikšana un parametru novērtējuma dažādība modelim ar noguruma plaisu rašanos kā sarūsējušiem, tā arī nesarūsējušiem tipiem: a (0),μ, ln Q un m – tie ir galvenie raksta diskutēšanas jautājumi.

Tiek pierādīts, ka korozijas ietekmei ir liels spēks uz nepieciešamo pārbaužu skaitu. Atslēgvārdi: noguruma plaisu rašanās, vidējā korozija, pārbaudes programma

Konstantin N. Nechval. Nogurumplaisu pavairošanas procesu stohastiskie modeļi, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 225.–231. lpp.

Lai izpētītu nogurumplaisu augšanas problēmas un uzsvērtu līknes augšanas variabilitāti jeb mainīgumu turklāt to vidējās augšanas gaitu, rakstā tiek piedāvāti četri nogurumplaisu augšanas modeļi. Starp šiem modeļiem var minēt Markova ķēdes modeli, Janga likuma spēka modeli, polinomiālo modeli un varbūtības log-lineāro nogurumplaisu augšanas modeli ar parametru, kas variē no vienības uz vienību saskaņā ar Weibull(σ,δ), lognormālo un normālo sadali. Var veikt eksperimentu, lai dabūtu nepieciešamos nogurumplaisu augšanas datus, kuri pēc tam tiek lietoti modeļu pierādījumam.

Atslēgvārdi: nogurumplaisas rašanās, stohastisks modelis, gadījumprocess, varbūtēja analīze Marijonas Bogdevicius. Dinamisko procesu simulācija mehāniskajā un pneimatiskajā sistēmā, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 232.–237. lpp.

Šajā rakstā tiek izskatīti procesi, kas notiek darbināšanās laikā asinhronajā dzinējā, savienojoties ar gāzi, kā arī mehāniskā darbināšana tiek izskatīta. Šī tipa apvienošana sastāv no atsevišķiem segmentiem, kur papildus masa tiek pievienota.

Gāzes kustība segmentos tiek aprakstīta ar vienādojumu nepārtrauktību, kustības daudzumu un gāzes stāvokli.

Iegūtie nelineārie vienādojumi tiek risināti ar Ņūtona metodes palīdzību. Atslēgvārdi: mehāniskā un pneimatiskā sistēma, spiediena vilnis, asinhronais dzinējs, skaitliskā

metode, simulācija Henrikas Sivilevičius, Kęstutis Vislavičius. Minerālmateriālu vienveidīguma ietekmes imitācija uz asfalt-betona sajaukumu šķirošanas stabilitāti, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 238.–244. lpp.

Autori rakstā izskata asfalt-betona sajaukuma, kas tiek lietots ceļu klājumos, vienveidīguma problēmu. Asfalt-betona sajaukuma daudzuma kompozīcijas vidējās vērtības un fizikāli mehāniskie parametri

pakļausies projektu un standartu prasībām. Cits svarīgs faktors, kas tiek atzīmēts rakstā, ir tas, ka sastāvdaļu daudzums atsevišķās partijās, ietekmējot daudzuma struktūras un raksturojumu vienveidīgumu, svārstīsies minimāli šaurā intervālā.

Piedāvātajā metodoloģijā tiek izmantota matemātiskās programmēšanas metode, izstrādāta programmatūra un veikts skaitļošanas eksperiments.

Atslēgvārdi: asfalt-betona sajaukums, šķirošana, vienveidīgums, matemātiskā imitācija, matemātiskā programmēšana

Mečislovas Mariūnas, Julius Griškevičius. Ārējo uzbudinājumu raksturojumu ietekmes izpēte uz dinamisko sistēmu “Cilvēks-ratiņkrēsls-transporta līdzeklis”, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 245.–253. lpp.

Sabiedriskā transporta sistēma bieži sastopas ar problēmām, transportējot indivīdus ar īpašām vajadzībām ratiņkrēslos, līdz ar to ir nepieciešami speciālie līdzekļi, lai to nodrošinātu.

Rakstā tiek piedāvāti minēto personu ratiņkrēslos dinamiskie un matemātiskie modeļi un tiek risināti trīs dinamiskās sistēmas kustības iespējamie gadījumi; tie ir šādi – stingra, noturīga kustība, daļējas vai pilnīgas atraušanās gadījumi. Veikta sistēmas dinamiskās stabilitātes skaitliskā analīze.

Atslēgvārdi: ratiņkrēsls, transportēšanas drošība, sabiedriskais transports, dinamiskā sistēma


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V. Yeremeyev, Т. Mamirov. Cieši saistīto diskrēto sistēmu identificēšana, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 255.–259. lpp.

Autori rakstā piedāvā jaunu rekursīvās identificēšanas sistēmas metodi. Īpaši cieši saistītu filtru modelēšanas rezultāti tiek parādīti.

Atslēgvārdi: cieši saistītie digitālie filtri, identificēšana, raksturīgais pierādījums Alexander Mrochko, Yury Sikerzitski, Vladimir Shelkovnikov. Īsviļņu sakaru līniju efektivitātes palielināšanās civilajā aviācijā, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 260.–262. lpp.

Autori rakstā izskata īsviļņu sakaru līniju efektivitātes palielināšanos civilajā aviācijā, kā arī, lai paaugstinātu sakaru līniju efektivitāti, tiek piedāvātas speciālas uztveres antenas lietošanai lidmašīnās. Daži šo antenu tipi tiek izskatīti konkrētajā rakstā.

Atslēgvārdi: ferro-elektriskās antenas, uztveres antenas sistēma, statistiskie raksturojumi Vladimir Shelkovnikov. Uztveres antenas efektivitātes analīze, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 263.–265. lpp.

Skaitliski jutīguma slieksni raksturo uztveres antenas efektivitāte. Autors rakstā parāda izteiksmes, kas raksturo elektriskās un magnētiskās uztveres antenas jutīguma slieksni. Ar šo izteiksmju palīdzību ir iespējams savstarpēji salīdzināt elektrisko un magnētisko antenu. Rakstā autors pierāda, ka magnētiskā uztveres antena ir efektīvāka nekā elektriskā, iedarbojoties dažādiem traucējumiem, kuriem būtībā ir elektrisks raksturs. Šādus traucējumus parasti rada industriālie traucējumi, kā arī dažādi citādi objekti, kuri ir izvietoti netālu no uztveres antenas.

Atslēgvārdi: uztveres antena, efektivitāte, jutīguma slieksnis Daiva Griskeviciene, Algirdas Griskevicius. Pasažieru starpmodalitātes iespējas Latvijā, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 267.–273. lpp.

Pasažieru apkalpes tirgus analīze un Lietuvas tālbraucēju pasažieru šodienas situācija parāda, ka galvenā vājā vieta šajā posmā ir organizētas pasažieru starpmodalitātes trūkums valstī. Stiprā puse ir tā, ka valstij ir veiksmīgs ģeogrāfisks izvietojums, labs ceļu stāvoklis, gaisa un ūdens infrastruktūra – tas viss stimulē pasažieru pārvadāšanas kvalitātes uzlabojumu un organizē starpmodālo apkalpes tīklu.

Vislabākā iespēja starpmodālai pasažieru transportēšanas ieviešanai ir organizēt labu interfeisu – Eiropas Savienības līmeņa pasažieru transportēšanas tīklu, kā arī integrēties starptautiskajā pasažieru apkalpes tirgū.

Atslēgvārdi: pasažieru transports, starpmodalitāte, tālbraucēji, dažādu veidu izmantošana, modālie konflikti

J. Butkevičius, A. Vyskupaitis. Pasažieru pārvadājumu attīstība ar jūras transportu Lietuvā, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 274.–279. lpp.

Rakstā tiek analizēti pasažieru pārvadājumi ar Lietuvas jūras transportu un tiek doti tā attīstības virzieni. Īpaša uzmanība tiek veltīta pārvadājumiem ar prāmi pa Baltijas jūru – pārvadājumu apjomi, darbība un ienākumu avoti.

Atslēgvārdi: jūras transports, osta, prāmju līnija, pasažieru pārvadājumi A. Pikūnas, V. Valiūnas. Nolietoto transporta līdzekļu un transporta ekspluatācijas materiālu risināšanas perspektīvas Lietuvā, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 280.–282. lpp.

Lietuva ir tranzīta valsts un līdz ar to cauri Lietuvai tiek transportēts bezgala daudz lietotu automobiļu. Automobiļi tiek transportēti no Eiropas uz Krieviju un Āzijas valstīm. Daudzas lauksaimniecības mašīnas un arī citi transporta līdzekļi paliek arī Lietuvā, tie ir ļoti veci, vecāki par 15-20 gadiem, ekspluatēt tos ir ekonomiski neizdevīgi. Pastāv arī problēma šo veco auto iznīcināšanā, tam visam ir jānotiek saskaņā ar Eiropas direktīvām – minētās un citas problēmas, saistītas ar šiem jautājumiem, tiek risinātas rakstā.

Atslēgvārdi: transporta līdzekļi, atkritumi, ekspluatācijas materiāli, automobiļi, perspektīvas Valdas Valiūnas, Aurelijus Vestartas. ABS sistēmas ietekme un transporta līdzekļu bremzēšanas distanci, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 283.–286. lpp.


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Mūsdienās transporta līdzekļos tiek pielietoti daudz un dažādi līdzekļi, lai paaugstinātu to drošību satiksmes negadījumos. Viena no tādām sistēmām ir ABS sistēma jeb anti-saslēguma bremzēšanas sistēma. Rakstā tiek diskutētas šīs sistēmas priekšrocības.

Atslēgvārdi: ABS sistēma, transporta līdzeklis, bremzēšanas ceļš

Darius Bazaras, Ramūnas Palšaitis. Loģistikas pakalpojumu attīstība un to pētījumu aspekti, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 287.–290. lpp.

Pēc stingri strukturētas un regulētas industrijas Lietuvas rūpniecība sāk savu darbību tirgus apstākļos, iegūstot neatkarību. Jauna domāšana un uzskati par loģistikas pakalpojumiem izveidojās visās kompānijās, kas ar to nodarbojās. Konkrētajā rakstā tiek izskatīta trešās personas loma loģistikas pakalpojumu sniegšanā.

Atslēgvārdi: loģistika, loģistikas pakalpojumi, trešās personas loģistikas pakalpojumi, efektivitāte

Daiva Griskeviciene, Algirdas Griskevicius, Albertas Simenas. Kravu pārvadājumi pa Lietuvas dzelzceļu un to perspektīvas, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 291.–300. lpp.

Raksta mērķis ir analizēt kravu pārvadājumu evolūciju pa Lietuvas dzelzceļu, tāpat arī tirgus attīstības iespējas, paredzēt transportēšanas perspektīvas un izstrādāt kravu pārvadājumu plānu līdz 2020. gadam. SWOT analīze tiek izstrādāta, pamatojoties uz Lietuvas dzelzceļa transporta sektora attīstības rādītājiem no 1997.-2003. gadam. Iekšējie un ārējie faktori tiek analizēti, kas iespaido kravu pārvadājumu evolūciju; tiek noteiktas perspektīvas un riska faktori.

Atslēgvārdi: dzelzceļa transports, kravu pārvadāšana, stratēģija, paredzējums Nijole Batarliene. Bīstamo kravu transportēšanas noteikumu informācijas modelēšana datubāzu vadības sistēmām, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 302.–306. lpp.

Datubāzu vadības sistēmu shēmu koherence un restrukturētā bīstamo kravu transportēšanas regulējumu bāze kā teorētiski, tā arī ar noteiktiem piemēriem tiek izklāstīta šajā rakstā. Bīstamo kravu transportēšanas noteikumi tiek modelēti līdz nedalāmam līmenim tā, ka tiem nav nekādu izņēmumu un norāžu uz citiem noteikumiem.

Šajā rakstā tiek dots restrukturizācijas rezultāts – dažādi elementāro noteikumu formālo sarakstu tipi, to radīšana un maiņas principi, kā arī datubāzu struktūra un algoritms datubāzei.

Atslēgvārdi: bīstamās kravas, transportēšanas noteikumi, vadības sistēma, datubāze Aldona Jarasuniene. Lietuvas dzelzceļa Informācijas sistēmu izvērtēšana un tās perspektīvas, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 307.–310. lpp.

Lietuvas dzelzceļa Informācijas sistēmas, Lietuvas dzelzceļa darbības un funkcionēšanas joma, kā arī investīcijas informācijas sistēmā skaitļos tiek atspoguļotas šajā rakstā.

Informācijas tehnoloģiju ieviešana tiek parādīta pa posmiem; departamentu savstarpējās sadarbības vērtējums, kā arī informācijas sistēmas kopējā lietošana ar citām valstīm tiek parādīta šajā rakstā.

Atslēgvārdi: Lietuvas dzelzceļa Informācijas sistēma, transporta līdzekļi, tehniskie raksturojumi, tehnoloģiskie dati, ieviestās informācijas sistēmas

V. Nykolsky, A. Latkov, Y. Svirchenkov. Gaidīšanas laika online kontroles metode skaitļošanas sistēmās ar rindām, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 312.–317. lpp.

Rakstā tiek izskatīta gaidīšanas laika online jeb tiešsaites kontroles metode datoru tīkla mezglam, sastāvot no ierobežotas jaudas vispārējas atmiņas un multiprocesora skaitļošanas vienības.

Atslēgvārdi: gaidīšanas laika metode, online jeb tiešsaites kontrole, algoritms Ramunas Palsaitis, Gintautas Labanauskas. Loģistisko centru saskarsme un Lietuvas ekonomiskā attīstība, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 319.–322. lpp.

Autori rakstā diskutē par loģistikas centru nozīmīgumu valsts ekonomiskajā attīstībā. Loģistikas centru izveides pamatā kā Kauņā, tā arī Viļņā un Klaipēdā tiek ņemtas vērā mūsdienu prasības, lai tie savukārt varētu nodrošināt pilnīgu kooperāciju starp lielajām tirdzniecības kompānijām un arī starp citiem loģistikas centriem Eiropā un ārpus tās.

Atslēgvārdi: loģistikas centri, transports, izmaksas, attīstība, krava


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Ieva Meidute. Loģistikas centru attīstība un perspektīvas Lietuvā, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 323.–328. lpp.

Loģistikas centru analīze parāda, ka šiem centriem nākotnē ir svarīga loma kravas pārvadājumu attīstībā un bez tam arī to vietu ekonomiskai attīstībai, kur šie centri ir izvietoti.

Lai Loģistikas centri atbilstu reģionālajām un Eiropas prasībām, tiem jāietver sekojoši raksturojumi: jāizvietojas TEN koridorā, nepieciešami augstas klases lielceļš un dzelzceļš, plašs darbības lauks, ievērojams distribūcijas daudzums, tīkla kooperācija, kooperācija starp Loģistikas centriem u.c.

Atslēgvārdi: loģistikas centri, transports, terminālis, attīstība Alexander Medvedev, Vladimir Zvonarev. Loģistikas centra vieta un loma mūsdienu apstākļos, TRANSPORT and TELECOMMUNICATION, 6.sēj., Nr.2, 2005, 329.–331. lpp.

Autori rakstā izskata kravas transporta problēmas Latvijā, kas radās pēc iestāšanās Eiropas Savienībā. Atslēgvārdi: kravas auto, transports, kompānija, Eiropas Savienība

The International Conference RELIABILITY and STATISTICS

in TRANSPORTATION and COMMUNICATION (RelStat’05) 13-14 October 2005. Riga, Latvia

PURPOSE

The purpose of the conference is to bring together academics and professionals from all over the world to discuss the themes of the conference: • Theory and Applications of Reliability and Statistics • Reliability and Safety of Transport Systems • Rare Events and Risk Management • Software Reliability and Testing • Modelling and Simulation • Intelligent Transport Systems • Transport Logistics and Economics • Education Programmes and Academic Research in

Reliability and Statistics

DEDICATION

The Conference is devoted to the memory of Prof. Kh.Kordonsky.

OFFICIAL LANGUAGES English and Russian will be the official languages of the Conference.

SUPPORTED BY:

Transport and Telecommunication Institute (Latvia) and The K. Kordonsky Charitable Foundation (USA) in co-operation with: Latvian Transport Development and Education Association (Latvia) Latvian Academy of Science (Latvia)

SPONSORED BY Transport and Telecommunication Institute (Latvia) The K. Kordonsky Charitable Foundation (USA) Latvian Operations Research Society PAREX bank (Latvia)

HOSTED BY

Transport and Telecommunication Institute (Latvia)

SECRETARIAT

Prof. Igor Kabashkin, Latvia - Chairman Mrs. Inna Kordonsky-Frankel, USA - Co-Chairman Mrs. Elena Rutkovska, Latvia – Secretary

DEADLINES AND REQUIREMENTS

Abstracts submitted for review should be a maximum of 600 words in length, should present a clear and concise view of the motivation of the subject, give an outline, and include a list of references. The abstracts should reach the Secretariat before September 5, 2005. Authors should provide a maximum of five key words describing their work. Please include the full name, affiliation, address, telephone number, fax number, and e-mail address of the corresponding author. Camera-ready documents must be handed in at the registration desk. Papers presented at the conference will be included in the conference proceedings. Instruction for papers preparing can be found on the conference WWW page: www.tsi.lv.

REGISTRATION FEE The registration fees will be Euro 50 before the deadline, and Euro 70 after the deadline. This fee will include: hard copy of the Conference Abstracts, hard copy of the Conference Proceedings (the proceedings will be mailed to the delegates after the conference), coffee breaks, Conference Dinner. Each registration fee might include just one paper, which presentation will be included in the conference program and published in the conference proceedings.

VENUE

Riga is the capital of the Republic of Latvia. Thanks to its geographical location, Riga has wonderful trade, cultural and tourist facilities. Whilst able to offer all the benefits of a modern city, Riga has preserved its historical charm. It's especially famous for its medieval part – Old Riga.

Old Riga still preserves many mute witnesses of bygone times. Its old narrow streets, historical monuments, organ music at one of the oldest organ halls in Europe attract guests of our city. In 1998 Old Riga was included into the UNESCO list of world cultural heritage.

ACCOMMODATION

A wide range of hotels will be at the disposal of participants of the conference and accompanying persons.

FURTHER INFORMATION Contact: Elena Rutkovska, Secretary, RelStat’05 Transport and Telecommunication Institute Lomonosova iela 1, Riga, LV-1019, Latvia Telephone: +(371)-7100665 Fax: +(371)-7100535 E-mail: [email protected] WWW: www.tsi.lv

Abstracts Submissions: September 5, 2005 Camera-ready final manuscript: October 13, 2005 Conference start: October 13, 2005

The K. Kordonsky Charitable Foundation

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