1 CHAPTER 8 Decision Support Systems Development.

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CHAPTER 8

Decision Support Systems Development

Fall, 2006 All Right Reserved, Zhong YAO, School of E&M, BHU

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8.1 DSS Development Issues

How to develop a DSS DSS must usually be custom tailored

– The application are diverse, ranging from data-oriented DSS to model-oriented DSS in different functional areas

– The vendors assisted in the DSS Construction

– Hardware, networking, man-machine interface and potential impact of DSS on the individual and groups. Software problem focused in this chapter

– Other problem are:


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8.1 DSS Development Issues– System development life cycle (SDLC)

– Prototyping

– Objective-Oriented Developing Method

– ROMC

– Organizing and forming the development team

– Complex process

– Technical issues

– Behavioral issues

– Different approaches


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8.2 DSS Development Platform General-purpose programming language, such as

COBOL or PASCAL. Little has been used in 1990s Fourth-generation language (4GL), like a SQL. OLAP with a data warehouse or large database DSS integrated development tool (generator, engine),

such as Excel, Lotus Domino. Domain-specific DSS generator, such SAS, MAPLE,

now Mathmatica, Matlab. Use the CASE methodology Integrate several of the above


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8.3 Traditional Systems Development Life Cycle (SDLC) (Waterfall)

Design

Implementation

Analysis

Need

Planning

System


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8.3 Traditional Systems Development Life Cycle (SDLC)

– Phase A-Planning,

– Phase B-Research,

– Phase C-System Analysis and Conceptual Design,

– Phase D-Design,

– Phase E-Construction,

– Phase F-Implementation,

– Phase G-Maintenance and Documentation,

– Phase H-Adaptation

Simplifying Into Four Phases:– Planning (Phase A, and Phase B)

– Analysis (Phase C)

– Design (Phase C , D, and E)

– Implementation (Phase F, G, and H)


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Planning - Why Build the System?

Minor Step Deliverable

1. Identify business value System request2. Analyze feasibility Feasibility study3. Develop work plan Work plan4. Staff project Staffing plan,

Project charter5. Control and direct project Project management tools

CASE toolStandards listProject binders / filesRisk assessment


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Analysis- Who, What, When, Where?


6. Analyze problem Analysis plan

7. Gather information Information

8. Model process(es) Process model

9. Model data Data model


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Design - How Will the System Work?


10. Design physical system Design plan

11. Design architecture Architecture design,Infrastructure design

12. Design interface Interface design

13. Design database and files Data storage design

14. Design program(s) Program design


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Implementation--- System Delivery


15. Construction Test plan,

Programs,

Documentation

16. Installation Conversion plan,

Training plan


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Common Implementation Headaches– No project team or management support

– Hazy purpose; no defined schedule; ballooning scope

– Unclear aspects of make vs. buy decisions

– Few project integrations are functional out of the box

– Qualitative benefits

– No user buy in

– Poor project management skills

– No accountability (责任 ) / no responsibility


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CASE Tools Functions– Information systems for systems analysts– Can help manage system development– Upper CASE (assists in analysis)– Lower CASE (manages diagrams and code generation)– Integrated CASE (both)

Often used tools:– Oracle Enterprise Development Suite– Rational Rose– Paradigm Plus– Visible Analyst– Logic Works Suite– AxiomSys and AxiomDsn– V32 & X32– Visual Studio


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Project Management (PM)– Team leader must have good PM skills– Major reason for IS development failures-bad PM skills– Only 26% of all projects surveyed (23,000) in 1998

succeeded– 28% failed, 46% challenged– Lower success rates for large companies– Better PM skills needed

Skills for Project Managers– Technology and business knowledge– Judgment– Negotiation


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– Good communication

– Organization Implementation Failures (DW Example)

– No user involvement

– No clear objectives stated early

– No real executive sponsorship

– Not appropriate for the DSS development


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8.4 Alternative Development Methodologies

Parallel development Rapid application development (RAD) methodologies

– Phased development

– Prototyping

– Throwaway prototyping


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Parallel Development– Multiple copies of design and implementation phases

– To develop separate subsystems

– All come together in a single implementation phase Phased Development

– Break system up into versions developed sequentially

– Each version has more functionality

– Evolves into a final system

– Users gain functionality quickly

– But initial systems are incomplete


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Prototyping (also called Evolutionary Prototyping

Process, iterative process, middle-out process, adaptive design, incremental design) Characteristics:– Performing analysis, design, and implementation

phases concurrently, and repeatedly– Users see system functionality quickly and provide

feedback– Decision maker learns about problem– But can lose gains in repetition

Aims: building a DSS in a series of short steps with immediately feedback from users to ensure that development is proceeding correctly.



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Developing processes:

– Select an important sub-problem to be built first. User and the builder jointly identify a subproblem for which the initial DSS is constructed. This early joint effort sets up initial working relationships between the participants and opens the lines of communication. The subproblem should be small enough that the nature of the problem, the need for computer-based support, and the nature of the at support are clear. It should have high interest value to the decision maker even if that interest is short-live.



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– Develop a small but usable system for the decision maker. No major system analysis or feasibility analysis is involved. In fact, the builder and the user go through all the steps of the system development process quickly, though on a small scale. The system should, out of necessarily, be simple.

– Evaluate the system constantly. At the end of each cycle the system is evaluated by the user and builder. Evaluation is an integral part of the development process, and is the control mechanism for the entire iterative design process. The evaluation mechanism is what keeps the cost and effort of developing a DSS



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– consistent with its value. At the end of the evolution a

decision is made on whether to further refine the DSS, or to stop.

– Refine, expand, and modify the system in cycles. Subsequent cycles expand and improve the original version of the DSS. All the analysis, design, construction, implementation, and evaluation steps are repeated in each successive refinement.

Advantages of Prototyping– Short developing time– Short user reaction time– Improve user understanding of the system, its

information needs, and its capabilities.



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– Low cost.

Disadvantages and Limitations– Gains maybe lost.

• Gains includes: Understanding Information systems benefits and costs, a detailed description of the business’s information needs, an easy to to maintain information system design, a well-tested information system, and well-prepared users.

– Combined with the critical success factor method

• Depend on the DSS built by the end-user or a DSS team.



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Prototyping

Design

Implementation

Analysis

Need

Planning

Prototype

System

Prototype Not OKPrototype OK


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Throwaway Prototyping– Like prototyping and SDLC

– Analysis phase is thorough

– Design prototypes assist in understanding the system

– Example: can use Excel, then Visual Basic Prototyping for DSS Development

– Problems are semistructured or unstructured

– Managers and developers may not completely understand problem

– Use prototyping


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Throwaway Prototyping (Figure 6.4)

Design

Implementation

Analysis

Need

Planning

DesignPrototype

System

Design PrototypeNot OK

Design

Implementation


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Why Prototyping?– Users and managers involved in every phase and

iteration

– Learning is part of design

– Prototyping bypasses the information requirement definition

– Short interval between iterations

– Initial prototype must be low cost


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8.5 Team-Developed DSS A team-Developed DSS needs:

– Substantial effort.

– Extensive planning and organization

– Some generic activities

– Group of people to build and to manage it

(users, intermediaries, DSS builder, technical support experts and IS personnel)

Size depends on

• Effort

• Tools

• For example, some project needs 2-3 people, but other maybe 15-20 people.


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8.5 Team-Developed DSS DSS development group varies:

– Within the IS department

– As a highly placed executive staff group

– Within the finance or other functional area

– Within the industrial engineering department

– Within the management science group

– Within the information center group The process that a DSS team may follow depends on the

specific application. The group may be temporary, created for a specific DSS, or it may be permanent, in which case the group members are assigned to specific DSS project.


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8.6 Team-Developed Versus User-Developed DSS

DSS 1970s and early 1980s were large-scale, complex systems designed primarily to provide organizational support. Therefore, these process needs team effort to complete and maintain.

Another approach is user-developed system.– Personal computers– Computer communication networks– PC-mainframe communication– Friendly development software– Reduced cost of software and hardware– Increased capabilities of personal computers– Enterprise-wide computing – Easy accessibility to data and models – Client/server architecture– Now OLAP– Balance


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8.7. End-user Computing andUser-Developed DSS

End-user Computing (end-user development): development and use of computer-based information systems by people outside the formal information systems areas. This definition includes many people, such as manager, professionals using PCs, Secretaries using Word processing tools, etc.

End-users Can be– At any level of the organization

– In any functional area

– Levels of computer skill vary

– Growing


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End-User Developed DSS Advantages

– Short delivery time

– Eliminate extensive and formal user requirements specifications

– Reduce some DSS implementation problems

– Low cost End-User Developed DSS Risks

– Poor Quality

– Quality Risks Substandard or inappropriate tools and facilities Development process risks Data management risks

– Increased Security Risks

– Problems from Lack of Documentation and Maintenance Procedures


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Issues in Reducing End-User Computing Risks

– Error detection

– Use of auditing techniques

– Determine the proper amount of controls

– Investigate the reasons for the errors

– Solutions

– Spreadsheet errors

• Should use same controls as normal IS


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•Age•Gender•Computer Confidence•Domain Experience•Application Expertise•Development Expertise•Math anxiety•Cognitive style

•Problem Complexity•Time Pressure•Existence of Review •Other

•Ad Doc•Structured

•Spreadsheet•Database•Others

•Reliability•Ease of use•Maintainability•Auditability•Cost

•Singles•Pairs•3+

Developer Attributes Application Type

End-user development Application Outcomes

Problem/process Char.

Developer Approach

Developer Configuration


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8.8. Objective-Oriented Developing Methods For DSS

Evolution of Objective-Oriented Technology

– Simula Language for replacing Simulation Language

– Use of auditing techniques (1967)

– Ada and Midula-2 for information hiding, (70s)

– Smalltalk, Xerox PARC, 1980

– C++, AT and T, 1981

– Visual Basic, Power Builder, Delphi etc. since 1994

– Java, C#, etc. 2000s


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Main Concept of Objective-Oriented Technology– To analyze and resolve the problems, the initial views

of the OOT is according to human being recognizing objective world and thinking ways

– Objective world consists of many concrete things or events, abstract concept, planning etc.

– Therefore, to study the problem of objective world, we can abstract them as objects. In OOT, the objects are basic elements. It is a core of analyzing problem.

– What is Object?• Is of independent operations and behaviors program.• Object vs. procedure.


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What is Object?– Actions executed by messages transferred between objects.– Each object possesses itself data structure and style for storing

data– Each object possesses independent interface for accessing by

other objects

Object 1

Object 2 Object 3

Object 4 Object 5 Object 6

User demand


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Object Class– If a object having same structure, operation, and the

following same constraint rules

– A class include: (1) name, (2) external interface, (3) internal presentation and (4) realization.

– Characteristics: – Class Specification---interface

– Realization--- each function how to do

– Hierarchy (Lattice)---farther class, sub-class, sub-sub-class etc.

» High level: generalization and commonality

» Low level: specials and details


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Characteristics of Objective-Oriented Technology– Abstraction: Any thing can be presented, structured and

unstructured. For example, table, chair, graph, sound, rule, concept etc. But similar things will be abstracted into same class for their similar operations, structures, and limits)

– Encapsulation: structure and procedure encapsulated into one whole class. This can be used for data hiding. Data in a class only can be accessed by its (this class) internal functions or data.

– Inheritance: subclass can inherit partial or whole properties of its mother class. The subclass can extend some special properties that the mother class don’t have.

– Polymorphism: one function can be used by different arguments.


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8.9. UML Technology for DSS

Resources: Universal Modeling Language– UML origins Booch Method91, 93; OMT-1 and –2

and OOSE (use case)

– 1994, Rational Software Corporation, combining Booch, OMT and OOSE into UML.

Concept of UML– Core view: 4+1;

• 4: Logical + Implementation + Process + Deployment

• 1: Use Case

• Figure presents with


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Implementation

View

Logical

View

Deployment

View

Process

View

Use Case

View

System Integrators

Performance, Scalability, Throughput

System Engineering

System Topology, Delivery Installation, Communication

End Users

Functionality

Programmers

Software Management

Analysts/Testers

Behavior


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9 standard Diagrams– Static Views

• Use Case Diagram

• Class Diagram

• Object Diagram

• Component Diagram

• Deployment Diagram

– Dynamic Views• Sequence Diagram

• Collaboration Diagram

• State Chart

• Activity diagram


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UML module– UML is Specifying(规范化 ), Visualization(可视化 ),

Documentation(文档化 ), and Constructing(结构化 ) software module language, its focus is on becoming a standard modeling language not on standard program language.

– Common metamodel(元模型 ) and Notation– UML is best for:

• OOT development• Component-based development• Higher Visualization Requirement • Components Reuse• Assisting Evaluation, statistical operating flows• Easy implementation


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8.10. Developing DSS: Putting the System Together

Development tools and generators – Use of highly automated tools

– Use of prefabricated pieces

– Both increase the developer’s productivity DSS Development System Includes

– Request (query) handler

– System analysis and design facility

– Dialog management system

– Report generator

– Graphics generator


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– Source code manager

– Model base management system

– Knowledge-base (management) system

– Object-oriented tools

– Standard statistical and management science tools

– Special modeling tools

– Programming languages

– Document imaging tools DSS Development System Components

– Some may be integrated into a DSS generator

– Others may be added as needed


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– Components used to build a new DSS

– Core of system includes development language or DSS generator

– Construction by combining programming modules

– Windows environment handles the interface


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8.11 Hardware & Software Selection

Hardware Selection– PCs– Unix workstations– Network of Unix workstations– Web servers– Mainframes– Typically use existing hardware

Software Selection (Complex because)– At start, information requirements, etc. are unknown– Hundreds of packages– Software updated rapidly– Price changes


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8.11 Hardware & Software Selection

– Many people involved in decision

– Language capability problems

– Different tools might be needed

– Many criteria

– Technical, functional, end-user, and managerial issues

– Inaccurate published software reviews

– Might prefer a single vendor Maybe use the AHP!!!


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8.12 DSS Technology Levels and Tools

Three Levels of DSS Technology

– Specific DSS [the application]

– DSS integrated tools (generators) [Excel]

– DSS primary tools [programming languages] Plus

– DSS integrated tools

Now all with Web hooks and easy GUI interfaces Relationships among the three levels (Figure 6.5)


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8.12 DSS Technology Levels and Tools

Specific DSS

DSS Generators (Spreadsheets, …)

DSS Tools (Languages, …)


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8.13 DSS Research Directions and The DSS of the Future

More AI Faster, more powerful computers The Web - interfaces and DB and model access More and better GSS ERM/ERP Knowledge management Better GUI Better telecommunications More research on theories More research on methods


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8.14 Supplement of Development Method

ROMC system analysis method: Aims Mainly: – The decision maker requirements and – Capabilities of the DSS.

Concept: Representation, Operations, Memory Aids, and Control Mechanisms

Representation: the user interface for the users of the DSS, (the displaying forms of the information required for the decision making, because any decision making needs lots of the information (such as charts, images, figures and equations))

Operations: manipulating the various information, including database retrieve, data sorting and calculating, plotting;


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of course, various of modeling calculations are also included. Memory Aids: mediate results need to store so that later

models or calculation to reuse. Therefore, Memory Aids design is the data structure and database design. It stores the variety of the valuable information and mediate results so that sequential operations to use. For example:

– Recording internal and external data

– Storing temporal results produced by an ad hoc analysis

– Reminding the decision makers for some operations backup design

– Directory of the status of information and the set values internally


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Control Mechanisms: All of above three aspects can support various decision process and status. Control Mechanism as a decision procedure combined uses the representation, operations and memory aids in which it depends on the styles , skills, and knowledge of decision maker.

There are two kinds of functions: – Building specification of using procedures and skills, e.g.,

using menu to select a manipulation, editing etc.– Online Help

ROMC analyzing procedure– Identifying various activities in each decision stage

For example, intelligence, design, choice, and implement.


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– Identifying the supporting functions for each activity.

– Building the key components of ROMC (identify the boundaries of the ROMC)

System design Application Case (Liang, textbook- a case of buying

a auto for personal)


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Assignments (individual)

Interpreting following concepts:– SDLC( or Describe the major phases of the

traditional SDLC. )– Prototyping– DSS teams or End-user Development– OODM– UML technology– ROMC– List eight ways in which companies speed up

application development. – Describe the features of Extreme Programming

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1 CHAPTER 8 Decision Support Systems Development.

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