Using organizational analysis and IDEF0 for

enterprise mode lling in SMEs

MARCO CANTAMESSA and EMILIO PAOLUCCI

Abstract. This paper deals with enterprise mode lling, and paysspecial attention towards the requirements of Small and

Medium Enterprises ( SMEs) . Among existing methodologies,SADT/ IDEF0 is examined and chosen as a starting point. After

having discussed some of the problems connected to the use of

such methodology, a new approach is propose d. Th is methodmay be seen as a bottom-up variant of SADT, which allows us toreduce the mode l development time, decrease the influence

of subjective viewpoints during the mode lling proce ss, andincrease the ease with which information in the model may be

subse quently processe d. Finally, the application of the

proposed methodology in a medium-sized enterprise is brieflyreported.

1. Introduction

The lite rature on enterprise mode lling and en-

gin ee ring is rich in terms of proposed methods and

approache s. This te stifies to the existence of a very live ly

re search activity in th is field. Howe ve r, as conce rns

in dustrial acce ptan ce of th e se m e th ods, th e fe w

em pirical studie s availab le in the lite rature show that

the se proposals are not wide ly applied in practice . For

instance , Deve reux et al. ( 1995) , in a survey cove ring

both `hard ’ and `soft’ innovations to m anufacturing

system s, reported that wh ile 70% of the compan ie s in

the sam ple used som e form of proce ss flowcharting in

support of the de sign proce ss, on ly 20% used a system

design methodology coming from lite rature or consult-

ing firms, and the re st used a m ethod deve loped `in

house ’ . Wh ile the relative youth of enterprise m ode lling

as a discipline partially explain s the lim ited diffusion of

th e se m e th ods, it m ay be valu able to in ve stigate

whethe r they may be improve d in order make them

more acce ssible to end users. Th is is particularly true in

the case of Small and Medium Enterprise s ( SMEs) ,

whose problem s and requirements are obviously some-

what differen t than those of large com pan ies.

Eve n though SMEs are not as com plex as large

com panies, the need for analysin g and redesign ing

the ir operations is no le sser than for the latte r, in orde r

to have them operate in an e fficien t and flexible way,

and to avoid, as often happens, that the ir proce sses

sim ply em erge from the unp lanned evolution of past

custom s and habits. Investing in enterprise mode lling

m ethods for SMEs is worthwh ile because of the we ll-

known economic re levan ce of such com pan ie s. More -

over, with today’ s blurring of the organ izational borders

along m anufacturing value chain s, or so-calle d `ex-

tended enterprises’ ( Porter 1985 , Browne et al. 1995) ,

re lative ly small and strongly focused com panie s tend to

becom e leading actors and building blocks of a new

industrial organ ization ( Howard 1990) . For such

com panies, expe rience with enterprise mode lling and

engin ee ring m ay becom e a strategic asse t enabling

them to in teract closely, e fficien tly and flexibly with

othe r firms. In th is pe rspective , Section 2 of this pape r

deals with a brie f revie w of e nterprise m ode lling

techn iques focussing on SADT/ IDEF0 as a particularly

suitable approach for SMEs. In Section 3, a nove l

approach for IDEF0 m ode l authoring is proposed, to

overcome som e disadvan tages of the traditional SADT

m ethod. Section 4 discusses how this approach may be

used in an ente rprise engin ee ring proje ct and, finally,

an application to a medium -sized company is described

in Section 5.

2. En terp rise m ode lling ap proache s

A num ber of re levant approache s for modelling an

enterprise in te rm s of its proce sses and com ponents

m ay be found in literature ( revie ws may be found in

William s et al. 1994 , CEN TC310 WG1 1994 , Brandi-

m arte and Can tam essa 1994) . The com ple xity of

e n te rprise m ode lling is such that the se d iffe ren t

INT. J. CO MPUTER INTEGRATED MANUFACTURING, 1998, VO L. 11, NO . 5, 416 ± 429

0951-192X/ 98 $12.00 Ó 1998 Taylor & Francis Ltd

Authors: Marco Can tam essa and Emilio Paolucci, Dipartimento di Sistem i di

Produzione ed Economia dell’Azienda, Polite cnico di Torino, Corso Duca degli

Abruzzi 24, 10129 Torino, Italy.

approache s may be assigned to different conceptual

leve ls and classified according to the following schem e

( Doum e ingts et al. 1995 ) .

( 1) Architectures and reference models ( e .g. CIMO SA

and GERAM) provide a standardized and

ge ne ric de scription of the enterprise e lem ents

and their re lationships. They are m ainly used

to clarify the hypothe se s upon what a gene ric

com pany is assum ed to be , so that furthe r

d e ve lopm e n ts m ay be base d upon th e m

( com m ercial system s in the case of software

vendors, and mode lling fram eworks and struc-

tured approache s in the case of re se arch

projects) ;

( 2) Modellin g formalisms are languages wh ich support

the representation, ge nerally in a graphical and

in tuitive manner, of various e lem ents of the

enterprise and under differen t pe rspective s.

Exam ples of such form alism s are IDEF0 ( Marca

and McGowan 1988 ) and Data Flow Diagram s

for repre sen ting functions, En tity ± Re lationship

diagrams and IDEF1X for represen ting in form a-

tion , IDEF3 ( Maye r et al. 1992) and GRAI Nets

( Doum eingts 1989) for repre sen ting behaviour.

More formal language s have also been proposed

for en terprise m ode lling, e .g. the CIMO SA

proce ss mode l ( Ve rnadat 1993) ;

( 3) Modellin g frameworks. An enterprise model ge n-

e rally require s the deve lopm ent of a number of

partial mode ls, deve loped with different formal-

ism s, each dealing with a specific perspective

and in a specific phase of the m ode lling proce ss.

Mode lling frameworks, e .g. CIMO SA ( Jorysz and

Vernadat 1990, AMICE 1993) , are conceptual

structure s used to coordinate the deve lopment

of these partial m odels;

( 4) Structured approaches or methodologies sugge st the

steps to be followe d when using a m ode lling

framework in an enterprise enginee ring proje ct.

Exam ples of such m ethodologie s are SSADM

( Cutts 1991 ) , GIM ( GRAI Integrated Me thodol-

ogy) ( Doum e ingts 1989 ) and PERA ( William s

1992) .

SMEs see king to im prove the ir m anufacturin g

operations m ay obviously find them se lve s a bit lost in

front of the vastne ss and com plexity of such an offer.

Howeve r, the se le ction of an appropriate approach can

be m ade easie r by clarifying the obje ctives of the

enterprise enginee ring project. In particular, it is

importan t to decide whe the r the focus is specifically

upon the deve lopment of a CIM system , or whethe r an

ove rall approach to com pan y re de sign should be

pe rformed, eve ntually having computer-based in tegra-

tion as one e lement.

The strong IT orientation of the form er choice

naturally leads towards the adoption of a fully-fledged

structured approach , e .g. CIMO SA or GRAI-GIM. In

such case s, en te rprise m ode lling require s to conside r

d iffe re n t vie ws upon the com pany ( e .g. function ,

in formation or behaviour vie ws) , and to reach a leve l

of de tail adequate to support the specification and

im ple m e n tation of a software syste m . Th e costs

attached to the enterprise mode lling e ffort may in th is

case becom e sign ificant in absolute te rms, but not when

com pared to the ove rall inve stment in CIM. Additional

e ffort spent upon in itial m ode lling m ay re sult in

conside rable savings of rework avoided in the subse -

quent phases of the project.

In practice , ve ry often , SMEs come to enterprise

m ode lling without having the clear in itial aim of

deve loping a CIM system . The ir e ffort is rathe r m ore

dire cted toward something m ore sim ilar to a Busine ss

Proce ss Re -e ngine e ring in itiative ( Ham m e r 1990,

McSwiney 1995) : the objective in th is case is to

obtain a pre lim inary understanding of `what is going

on ’ in the com pany, and to identify the areas in

which organ izational and proce ss rede sign, toge the r

with IT system s rede sign, m ay contribute to im proving

operational perform ance . Afte r this has been accom -

plished, it may be possible to go some steps forward

by using m ore structure d and de tailed approaches. In

oth e r words, SMEs particu lar ly ne e d e n te rprise

m ode lling approaches for perform ing analysis at a

conceptual de sign leve l. Such pre liminary studie s

m ostly deal with functional aspects, because they are

the m ost apparent and bring busine ss processes in to

focus. They should be pe rformed without too much

e ffort, wh ile at the same tim e providing a sound basis

for further deve lopments ( e .g. adding othe r m odel-

ling vie ws and going deepe r in te rm s of leve l of

de tail) . More specifically, the following requirements

m ay be proposed ( see Colquhoun et al. 1996 for a

sim ilar list) :

( 1) the m ode lling approach must be simple to use

by non-expe rts ( SMEs ge ne rally do not have

enough resource s to dedicate specially trained

staff for enterprise m ode lling tasks) ;

( 2) mode ls must be easily inte rpre ted and discussed

by all the actors involve d in the innovation

process in orde r to increase their comm itm ent;

( 3) mode ls should be used as a basis for furthe r

deve lopments with min im al adaptation;

( 4) mode ls should he lp to identify opportunitie s for

syste m im prove m en t ( Dave nport and Short

1990) ;

Enterprise modellin g in SMEs 417

( 5) the m ode lling process must be as quick and

economical as possible , thus reducing expenses

in exte rnal consultancy or in distracting in te rnal

pe rsonne l from their usual work;

( 6) mode ls must be agile and concise, so that the ir

continuous m ain te nance may be viable and

economic. Th is is e ssen tial for initiating a true

`continuous im provem ent’ proce ss.

Despite some unden iable lim itations ( Billo et al.

1994) , the approach that probably ge ts close r to

fulfilling such requirements, and especially the former

four, is SADT/ IDEF0. Th is structured analysis approach

has become , since its first proposal in the early 1970 s, a

de facto standard for proce ss mode lling in industrial and

busine ss environments ( Colquhoun et al. 1993) . O f

particular in terest is IDEF0’ s un ive rsality, i.e . a language

wh ich has been used in academia and industry alike ,

across a wide range of busine ss sectors and with a

worldwide diffusion . Among the advan tage s of IDEF0,

one can m ention its expre ssive power, the intuitivene ss

of its use and the possibility of using it for functional

mode lling within a num ber of en terprise m ode lling

fram eworks. Am ong these , one can rem ember the IDEF

fam ily of formalisms ( where it is com monly com ple -

men ted with IDEF1x for in form ation m ode ls and

IDEF3 for behavioural m ode ls) and GIM ( in connec-

tion to GRAI grids and nets) . Moreove r, the building

blocks of IDEF0 are close to the enterprise activity

construct used in the CIMOSA function view.

Proper use of IDEF0, howe ve r, is not exem pt from

shortcomings, e specially with re spect to the two latte r

requirem ents. The original proposers of SADT have

always stressed the importance of taking great care of

the m ode lling proce ss and of inve sting suitable effort

into it. The user must be conscious that the final results

will essen tially depend upon the quality of such a

proce ss ( Marca and McGowan 1988) . Unfortunate ly,

th is recommendation often goes unheeded by m any

analysts who, pressed by tigh t time constraints, use

IDEF0 in an approxim ate and in form al way; in th is case ,

the in tuitivene ss and simplicity with wh ich m ode ls are

laid down may become misleading, and induce the

deve lopm ent of incorre ct or poorly focused mode ls.

More specifically, a critical aspect of IDEF0 m ode l

authoring is due to the subje ctive bias that the analyst

naturally tends to cast upon the mode l, based upon

prior experience and to the way with wh ich he or she is

accustom ed to in te rpre ting and looking at re ality

( Busby and William s 1993) . Th is phenom enon will be

enhanced in the case of low involve m ent by the

organ ization ’ s m embers. The risk of subjective bias

has a connection to the fact that IDEF0 m ode ls are

gene rally deve loped using a top-down decomposition.

Working top down require s a sign ifican t conceptual

e ffort in identifying a proper decom position of the

system into a subsystem hie rarchy, and it is ve ry easy for

the analyst to pe rform such a task rathe r roughly, by

drawin g new models from previously deve loped ones

and without payin g enough attention to the ir appro-

priate ne ss to the pre se n t case . Anoth e r fre quen t

problem in IDEF0 mode lling is connected to incon-

sistencie s in in formation flow wh ich are com monly

found in manufacturing system s ( i.e . activities that

re ce ive m ore or le ss inform ation than required, or that

produce in form ation which goes unused) . Actors in the

system , pressed by an analyst attem pting to deve lop an

orde rly and consistent model, often tend to allow him

to `fix’ such problems. Th is leads to a represen tation

which , although desirable , is not a faith ful picture of

the system and will h ide these problem s when the

m ode l will late r be analyse d.

To avoid such risks, the `golden rule ’ of IDEF0

m ode lling prescribes that the authoring proce ss be

m ade up of a lengthy sequence of m ode l writing and

revising phase s, during wh ich the analyst and mem bers

of the organ ization should be ite rative ly involve d and

com m unicate rathe r in tensive ly. As a re sult, deve loping

a good mode l often require s a few m onths time eve n for

a m ode l of limited size ; for a sm all company th is

gene rally becomes a far too demanding task from both

the organ izational and econom ic points of view. More -

over, extending the mode lling proce ss duration has a

number of othe r undesirable consequence s, e .g. a

decrease in comm itm ent on behalf of the organ iza-

tion ’ s m embers, the deve lopment of a m odel wh ich will

be obsole te from the start, and, finally, the inclination

to pe rform an unnece ssarily de tailed analysis, thus

m aking the mode l extrem e ly cumbersome and difficult

to understand.

To face these problems, proposals have been made

to re duce th e e ffort con ne cte d to IDEF0 m ode l

authoring, principally by followin g two differen t paths.

O n one side , som e authors have worked on IDEF0

m etamode ls ( Fung 1993 , Ang et al. 1994 ) : the se are

gene ric m ode ls which should be able to de scribe the

m ain feature s which are peculiar to com pan ie s in a

ce rtain industry, and essen tially propose a standard

h ierarch ical decomposition , toge ther with the principal

in formation and m aterial flows, controls and resource s.

In orde r to deve lop a specific mode l, the analyst should

adapt the m etam ode l’ s structure ( ge ne rally by pruning

or merging diagrams) and then enrich the re sulting

m ode l with company-specific activitie s and entities. The

proce ss followe d, the re fore, seems to be ve ry sim ilar to

CIMO SA’ s conce pt of `stepwise instantiation ’ of a

specific system by starting from a re fe rence architec-

ture . Toge the r with metam ode ls, authors often propose

M. Can tamessa and E. Paolu cci418

more or le ss com plex guide line s for mode l instantiation

and have deve loped software tools to support them,

som e tim es usin g Artificial Inte lligence techn ique s.

Me tamode ls speed up the mode lling proce ss and, in

principle , allow unskilled analysts to carry out com plex

mode lling tasks, because m uch of the e xpe rie nce

re quired is incorporated in the m etam ode l itse lf.

Howeve r, the risks associated with forcing the com plex-

ity of a specific en terprise to fit into a prefabricated

scheme re sulting from past expe rience now becom e

even h ighe r: expe rience , by its own nature , at least

modifie s itse lf ove r tim e , while a rigid scheme such as a

metamode l is more difficult to change . In conclusion,

me tamode ls may be a precious support indeed, but only

if the analyst has sufficient critical ability to find out the

ine vitable inconsistencie s wh ich e xist be tween the

metamode l and the real system, and to change the

former where nece ssary.

O the r authors, in stead, have proposed modifica-

tions to the IDEF0 language in orde r to take out some

of its difficultie s, mostly by sim plifying model structur-

ing. Among these , Billo et al. ( 1994) propose diagram s

based upon the so-calle d `triple diagonal’ , where the se

diagonals, re spective ly, correspond to plann ing, control

and execution activitie s. Triple diagonal m ode ls are not

hie rarch ically structured and the re fore show all re le -

vant data upon a single diagram; furthe r de tails m ay be

mode lled by using anothe r tool, e .g. the `use r concept

diagram ’ ( Hostnik et al. 1985) . Th is is a sort of iconic

enhancem ent of standard proce ss flow-charts, in wh ich

cycle tim es and areas of re sponsibility are m ade explicit.

This and other proposals seem to be prom ising, indeed

under m ultiple poin ts of vie w, e.g. the ease of writing,

validating and also in terpre ting mode ls; howeve r, they

have not yet evolve d in to a wide ly accepted standard,

and the ir industrial applicability may at presen t be

hinde red by this.

3. A bottom -up ap p roach to IDEF0 m od e l au thoring

In order to make the potential of IDEF0 more easily

availab le to SMEs, we have m ove d in to a third dire ction

by revisiting the usual m ode lling approach. Inspiration

for th is approach has com e from organ izational analysis

technique s ( Leife r and Burke 1994 ) , in which in form a-

tion on the organ ization and its busine ss proce sses is

systematically gathe red, loaded into a database and,

finally, analyse d with statistical techniques. The hin t is

to do the sam e for enterprise m ode lling, by colle cting

de tailed in form ation about the activities pe rform ed in

the system through personal inte rviews and/ or ques-

tionnaire s, and then to use such a database as an

in termediate model from wh ich to build other m odels of

the system , IDEF0 in primis. In othe r words, the idea is

the following ( figure 1) : the IDEF0 mode l ( wh ich we

will nam e `X’ ) is a view of reality `R’ , re stricted to

functional aspects and hierarch ically structured. Now, if

one deve lops a wider in te rmediate m ode l of reality, `Y’ ,

then the model X can be derived from Y instead of R

( by `wide r’ we m ean th at Y e ncom passe s all the

in form ation contained in X) . Furthe rm ore , if the

proce sses of obtain ing Y from R, and X from Y are

colle ctive ly le ss burdensome than the proce ss which

dire ctly extracts X from R, then we have found a

conve n ient alternative approach to IDEF0 m odelling.

Working with an in termediate m ode l has othe r

advan tage s. First, when othe r mode ls will have to be

deve loped to cove r different vie ws of the system , the se

m ay be drawn directly from the inte rmediate mode l,

without havin g to start a complete authoring proce ss for

e ach of them ( thus savin g m any tim e -consum ing

sessions for inte rviews and revisions with individuals

and groups) . More ove r, the com mon interm ediate

m ode l m ay he lp to main tain consistency be tween the

various partial mode ls of the sam e system . A som ewhat

sim ilar concept, but re lated to a much wide r scale

framework, m ay also be found in the CIMO SA process-

based mode lling approach ( Vernadat 1993) , as well as

in some othe r re cent proposals for en terprise enginee r-

ing ( Agu iar and Weston 1995 , Koonce et al. 1996) .

Finally, through the inte rmediate mode l, it is re lative ly

easy to obtain mathem atical repre sen tations of the

m anufacturing system ’ s entities and their re lationsh ips,

thus allowing us to analyse the system with quan titative

m ethods. Th is option offers a powe rful tool for high -

ligh ting problem s and solution opportun itie s in the

system , and it makes analysis tasks easy and straightfor-

ward, com pared to going through the large number of

diagram s wh ich m ake up an IDEF0 mode l.

Enterprise modellin g in SMEs 419

Figure 1. Mode l authoring through an intermediate mode l.

Th e in te rm e d iate m ode l has to be de sign e d

according to the m ode ls which will be based upon it,

and the formalisms with wh ich they will be deve loped.

Be cause this pape r focuses upon IDEF0, the in te rm edi-

ate mode l is somehow sim ple and is depicted as an

Entity-Relationsh ip Diagram in figure 2 ( for simplicity,

en tity attributes have not been listed in the diagram) .

Of course , the mode l may have to be augmented in the

case when othe r partial mode ls have to be deve loped in

coordination with the IDEF0 one, e .g. an IDEF1x m ode l

for de scribing inform ation , and/ or an IDEF3 model for

behaviour. Finally, it m ay be noted that the mode l in

figure 2 is sim ilar to the CIMOSA defin ition of function

vie w concepts; its m ain elem ents are the following:

· activ ities ( IDEF0 `boxe s’ ) are the elem entary un its

wh ich m ake up busine ss proce sses. Like in IDEF0,

each activity is characte rized by its inputs and

outputs ( wh ich may be both physical en tities or

in form ation) , as we ll as by the re source s and

controls which, respective ly, support and in flu-

ence its exe cution ;

· entities and in formation ( IDEF0 inputs, outputs and

controls) ; processes are made up of a flow of

physical en tities ( e .g. parts, raw m aterials, fixtures,

e tc.) and information . The in termediate m ode l

describe s each of the se flows and records wh ich

resource Ð if any Ð is in charge of it ( th is is an

additional in form ation re spect to IDEF0) ;

· resources ( IDEF0 m echan isms) ; activitie s are exe -

cuted by the inte rvention of re source s, be they

hum an or m ach ines, wh ich are de scribed in the

in te rm ediate mode l. As mentioned above, each

resource is also directly re lated to entity and

in form ation flow am ong the activitie s they are

involve d in;

· departmen ts; in orde r to make it easier to apply the

mode l to industrial ente rprises, each resource is

associated with a com pany departm ent. Th is

allows us to consider the authority and responsi-

bility flows to wh ich each resource is subordinated.

When such an in termediate m ode l is availab le , the

IDEF0 m ode l m ay be deve loped by extracting the

in formation it contain s. Apparently, the re is a problem

here in that such information is re lated to low-leve l

activitie s, and in IDEF0 m ode lling it is custom ary to

vie w these activitie s as the product of a top-down

decom position process, rathe r than as a starting point.

Now, the proposal wh ich comes from this in te rm ediate

m ode l-based approach is to re th ink th is procedure

and deve lop IDEF0 m odels from the bottom up by

aggre gatin g, rath e r th an de com posin g, ac tivitie s.

There are advan tage s to th is, which allow us to

overcome som e of the previously discussed problem s

connected to IDEF0 mode lling. The main bene fit is

that low-leve l activitie s and the ir in te ractions are

identified directly by the actors involve d in the system

and with m in im al in te rve ntion on behalf of the

analyst. There fore, inconsistencies in the in form ation

flow will appear right away, without tem pting the

analyst in to `fixing’ them to ensure mode l consistency.

Moreove r, the m ode l structure built by bottom -up

aggregation will fit a give n and stable se t of activitie s,

while in the usual top-down approach the analyst will

tend to influence activity identification in orde r to

m ake them fit the mode l structure wh ich he or she

has in mind and has deve loped up to that mom ent.

The concept m ay be clarified, eve n if not form ally

proved, through a toy exam ple , wh ich shows the kind

of problems encountered ( even though the scale of

the se problems is so reduced that they m ay appear

trivial) .

By in tervie wing its CEO , the `top-down analyst’

finds out that com pany XYZ has two departm ents,

M. Can tamessa and E. Paolu cci420

Figure 2. Simplified Entity ± Re lationship representation of the intermediate model.

`product deve lopm ent’ ( PD) and `production’

( P) . The analyst then create s the A0 diagram of

figure 3( a) and in te rviews the m anagers in charge

of the se two departm ents. The PD m anager

identifies h is department’ s activitie s as `product

de sign ’ and `process de sign ’ , wh ile the P m anager

declare s his workforce is engage d in `proce ss

de sign ’ and `m anufacturing’ ( the reason is that

proce ss de sign is pe rformed by product designe rs,

with the aid of shop floor pe rsonnel) . Now, the

m ode l de rivin g from th e A0 decom position

should be revised because it is doubtful that the

two-way partition of operations in PD and P may

still be accepted in the ligh t of the se new findings.

The analyst may anyway be tempted to avoid th is

revision by forcing `proce ss de sign ’ e ither in the

PD activity box, or in the P activity box or, more

creative ly, by placing two `proce ss de sign ’ activitie s

in both PD and P.

A `bottom -up analyst’ would instead go directly

for low-leve l activitie s and understand that there

are three of them , i.e . `product de sign ’ , `proce ss

de sign ’ and `m anufacturing’ , the second of wh ich

be ing join tly pe rform ed by people be longing to

two differen t departments. The proposed decom -

position ( or, more accurate ly, com position) of the

system would immediate ly appear as that of figure

3( b) . The top-down analyst would obtain such a

proposal on ly through a revision of h is in itial

proposal, not accounting for the risk of not doing

so, and the re fore deve loping a distorted m ode l.

The first result of bottom -up aggregation , the refore,

is an IDEF0 m odel that m ore faith fully represen ts the

real system. Moreove r, in the ligh t of experience gain ed

with th is me thod, and as will be de scribed in Section 5,

the mode lling process becom es quicker, because having

de fined low-leve l activitie s since the beginn ing allows us

to reduce the num ber of authoring ite rations with

actors of the system. These ite rations also change in

nature , and gene rally deal with sim ple issues such as

clarifying te rminology, rathe r than with m ore complex

problem s, such as in te rpre tin g syste m beh aviour.

Conce rn ing the h ie rarch ical aggre gation of activitie s,

the approach followed up to now is pure ly m anual and

is straightforward to accom plish . If de sired, it is also

possible to use autom atic approach e s for m ode l

structuring, such as the one proposed by Kusiak et al.

( 1994 ) .

Without any change to the in te rm ediate m odel

shown in figure 2, it is also possible to obtain

another inte resting vie w of the m anufacturing system ,

based upon incidence and adjacency matrice s ( see

figure 4) , wh ich allows us to m athematically repre -

sent inte ractions be tween the four obje ct classe s

conside red:

· the Resource / Activity matrix shows wh ich activ-

itie s are performed by each resource . Analysis of

the matrix m akes it possible to identify exce ssive

or insufficient workloads cast upon people , as we ll

as activitie s in wh ich too few ( or too many)

re source s are involved. Proce ssing th is incidence

matrix also allows us to find clusters of re source s

and activitie s, thus supporting the formation of

workgroups; th is is analogous to the way in which

mach ine s and parts are grouped toge the r in the

Production Flow Analysis approach in Group

Enterprise modellin g in SMEs 421

Figure 3. Top down versus bottom up development of an IDEF0 mode l.

Technology, and m any algorithm s deve loped in

th is area can be readily adapted for this type of

problem ( a com prehensive survey of such meth-

ods m ay be found in Offodile et al. 1994 ) ;

· the Department/ Activity matrix is similar to the

previous one , but aggregate s inform ation at a

department leve l, by showing which departments

are in volve d in each activity and h ow m any

resource s are deployed;

· the Resource / Re source matrix allows to us analyse

in form ation and mate rials exchange d am ong each

couple of re source s in the system . Analysing th is

matrix allows us to be tter understand the system ’ s

structure , and to rede sign both the in form ation

flow and the media with wh ich inform ation is

exchanged;

· the Departm ent/ Departm ent m atrix is sim ilar to

the previous one, but ope rate s on department-

leve l inform ation .

4. Using the prop osed m e thod in en terp rise

engin ee ring

It is now possible to brie fly de scribe how the

proposed approach to IDEF0 m ode lling may be used

with in an enterprise enginee ring proje ct. The metho-

dology used ( figure 5) is a fairly standard one , and is

based upon the m ode lling of the existing ( `As-is’ )

system , the design of a `Should-be ’ targe t and the

de fin ition of a migration plan leading to the desired

goal. There fore , the de scription will be concise and

focus upon the specific characte ristics connected to the

m ode lling approach being proposed.

4.1. Phase 1: bu ilding the `As-is’ model

The main objective of th is phase is to mode l the

curren t situation of the system . The in te rmediate m odel

is to be deve loped at first; afte rwards, two othe r `As-is’

m ode ls will be de rived from the former, re spective ly,

using the IDEF0 language, and the incidence and

adjacency matrice s. The `As-is’ mode l may be built

according to three m ain steps.

· Preliminary analysis. The analyst ach ieve s a pre -

lim inary understanding of the com pany and its

structure ; he or she circum scribes the part of the

com pany upon wh ich to act and, with in th is

portion , identifies the main actors, ope rations

and in teractions with the re st of the com pany.

· Activity analysis. The analyst system atically inte r-

views, e ithe r ve rbally or using questionnaire forms,

M. Can tamessa and E. Paolu cci422

Figure 4. Examples of Activity/ Resource, Activity/ Department, Resource/ Resource and Department/ Department matrices

( clockwise , from uppe r left) .

the actors involve d in the system be ing studied.

The inform ation gathe red is the sam e as indicated

by figure 2, and concerns the activitie s pe rform ed

by actors and the in teractions am ong them.

· `As-is’ model defin ition . The comple ted database

now allows us to produce two differen t vie ws of the

system : the IDEF0 mode l, deve loped by aggregat-

ing activitie s h ierarch ically, and the tabular mode l,

deve loped by extracting the incidence and ad-

jacency m atrice s.

4.2. Phase 2: `As-is’ model analysis an d `Shou ld-be’ model

bu ilding

The aim is to analyse the `As-is’ mode l, so as to

pinpoin t the curren t de ficiencie s and limitations of the

manufacturing system. Th is will lead to a `Should-be ’

mode l, that is a represen tation of the de sired goal towards

wh ich the company should tend. By com paring the `As-is’

and `Should-be ’ m ode ls, a sequence of innovative actions

may then be de signed and implem ented. Th is phase may

be performed through three m ain steps.

( 1) Defin ition of objectives and performan ce measu res.

Th is step is needed so that the curren t and

desired system s may be evaluated with re spect to

a stable fram e of re fe rence . O f course , the

se tting of obje ctives is a strategic matte r which

stands far ahead of the re -enginee ring task

wh ich is being addre ssed in th is pape r, and the

reade r should the re fore refe r to related lite ra-

ture ( Govindarajan and Shank 1992) . The sam e

holds for deciding, give n such objectives, which

pe rformance m easures should be used.

( 2) `As-is’ model analysis. The `As-is’ mode l is to be

analyse d in orde r to find its main drawbacks,

e specially in re lation to the previously e stab-

lished perform ance measure s. Now, such pro-

b le m s m ay h ave d i ffe r e n t o r ig in s a n d

m agnitude s; in orde r to point them out, the

two mode ls are complem entary and have to be

used alte rnative ly. Problem s at a minor scale

m ay be found using low-leve l IDEF0 diagrams or

ve ry specific querie s upon the tabular vie w;

conve rse ly, de ficiencie s connected to system

structure are spotted by working on e ither the

Enterprise modellin g in SMEs 423

Figure 5. Outline of the proposed methodology.

IDEF0 hie rarchy or the ove rall tabular mode l.

The kind of e ffort to be spent in analysing the

m ode ls the refore depends on the desired kind

of innovation , whe ther it is a radical in tervention

( e .g. a comple te busine ss process re -enginee ring

project) , or an incremental innovation ( e .g. an

activity to be perform ed at fixed inte rvals with in

a continuous improve ment program) .

As a m atte r of fact, the re is no fixed rule for

analysin g th e `As-is’ m ode l. Howe ve r, it is

conve n ient to define a se t of comm on criteria

an d d iagn ostic que stion s for spottin g th e

system ’ s ine fficiencie s, which may be gradually

incre m en te d wh ile the an alyst’ s e xpe rience

grows. Such analysis m ay be facilitated if the

database contain ing the in te rm ediate mode l

allows us to form ulate detailed querie s with

e ase , sin ce a com ple te an alysis com m on ly

requires us to try out a long series of such

in te rrogations ( e .g. `extract all com munications

of type chan ge to prev iou s order wh ich are

pe rform ed verbally between departmen t X and

department Y’ ) . As a sam ple of such questions,

four com mon and useful one s may be listed :

· the Activity/ Re source incidence m atrix al-

lows us to see wh ich people have to support

too m any activitie s or, conve rsely, to find out

activitie s wh ich are e ithe r understaffed or

perform ed by too many people at the sam e

time ( probably without any coordination) .

Moreove r, workgroups may be formed by

proce ssing the incidence m atrix, e ithe r by

sigh t, or with clustering algorithm s able to

sort out the `natural’ groups of resource s in

the system;

· re source / Re source and Departm ent/ Depart-

ment adjacency matrices allow us to spot

opportunitie s for e stablishing in terfunctional

teams, whenever it is found that a ce rtain

group of people have in tense and frequent

comm unications among themse lve s;

· adjacency matrice s comm only help in identify-

ing people who spend a sign ifican t part of the ir

time givin g advice and in form ation to collea-

gue s. In th is case , it m ay becom e necessary to

support th is in form ation tran sfer ( e .g. by

inse rting such in formation in a database or

sim ply posting it on a billboard) , and to value

the role of such provide rs of expert knowledge;

· by analysin g the IDEF0 mode l it m ay be

possible to find activitie s wh ich are unnece s-

sary ( often called non value -adding ones) ,

duplicate ( be ing exe cuted separate ly by dif-

feren t people at the sam e time ) , bottlenecks

( when too many activitie s depend upon the ir

com ple tion) , candidate s for be ing put in

paralle l ( it often happens that the sequencing

of activitie s is ju st a h abit, but n ot an

operational nece ssity) .

( 3) `Shou ld-be’ model defin ition ; afte r having analyse d

the `As-is’ m ode ls, and keeping in mind ge ne ral

obje ctive s and constraints, the aim is to de fine a

goal state for the system ( represen ted by the

`Should-be ’ mode l) . Th is may be done by going

ove r the list of deviations found in the previous

phase and, starting from the large r-scale ones,

corre cting them one at a tim e. The re sulting

`Should-be ’ m ode l is, as usual, give n by the

in te rmediate m ode l, and the two m ode ls, IDEF0-

and m atrix-based.

4.3. Phase 3: defin ition and implementation of the `Migration

Plan ’

The objective of this phase is to compare the actual

and the de sired system state ( i.e . the `As-is’ and the

`Should-be ’ m ode ls) . Such comparison allows us to

de fine a sequence of steps that may gradually lead to

the `Shou ld-be ’ state . Proposed m odifications m ay

essen tially be of thre e kinds: organ izational, procedural

and related to in formation system s. In the presen t

phase , it is wise to set priorities for such innovations by

using the previously de fined performance metric, and

conside ring both costs and technological constraints.

Im plementation of the migration plan require s that,

from a simple list of actions, a comple te project be

planned and exe cuted; it is clear that, during th is

phase , Proje ct Man age ment techn ique s m ay be of great

he lp. Moreover, im plem entation of the Migration plan

require s attentive m anage m ent conce rning the alloca-

tion of authority, e specially if the plan regards more

than one of the company’ s departments.

4.4. Phase 4: auditing of the process

The last phase has the obje ctive of ve rifying all the

previous re sults and, specifically, the proposed solutions

and the ir gradual implem entation . Th is activity has the

imm ediate aim of finding corrections wh ich may be

in troduced while the innovation process is still ongoing.

However, the true aim is to initiate a continuous

improvem ent proce ss wh ich may continue long afte r

the present in te rve ntion has been comple ted. In fact, a

com m only raised criticism on enterprise enginee ring

M. Can tamessa and E. Paolu cci424

methods is that they lead to an overwhe lm ing amount

of mode ls and recomm endations, which very soon

becom e forgotten and unheeded. The current proposal

trie s to overcom e this problem , on one side by havin g

facilitated mode l deve lopment and analysis, and on the

othe r side by inse rting this auditing phase .

5. Case stud y

Th is section will brie fly describe the application of

the proposed m ethodology in Com pany E, an Italian

medium-size firm located close to Turin, employin g

about 1100 workers. E produce s e le ctromechanical

components for the automotive and e le ctron ic appli-

ance s industries, and is a European market leader in

th is sector. The me thodology was applied in one

departm ent of the company having a workforce of

about 100 persons, thus justifying the connection with

SMEs.

E is an in n ovative com pan y wh ich draws its

competitivene ss from continuous innovation and qual-

ity of products. In orde r to reinforce th is capability, an

in te rnal program for `continuous im prove m ent’ was

started in late 1992 , and a dedicated staff directly

depending from the CEO was appoin ted. During 1993

and 1994, the staff re -de signed the work flow and

busine ss proce sses of about half of E’ s m anufacturing

departm ents. Howe ve r, the lack of an accurate and

e fficient m e thodology m ade th is proce ss tim e consum -

ing and expensive . The in itial analysis of each depart-

m ent was laborious, and the re was no tool availab le to

re -use part of the expe rience gain ed in previous

analysis.

In orde r to ove rcom e the se problems, E decided to

try out the proposed methodology on the plastic

in je ction moulding departme nt in 1995. Th is depart-

m ent is particularly critical for the com pany, both

because of the technological complexity and varie ty of

its activitie s, and for the impact it has upon down-

stream departments, conce rn ing ove rall lead-time and

quality. Currently, E’ s customers require a few part-

pe r-m illion de fect rate s and a JIT de live ry lead-time of

three days, de spite considerable geograph ical distance s

Enterprise modellin g in SMEs 425

Figure 6. `As-is’ A0 diagram of the case study.

and a rather uneve n dem and. A late 1994 e stimate

reve ale d th at une xpecte d eve nts, and in e fficien t

organ ization and manage ment of the production flow

we re causing an ave rage equipm ent idle time of about

20% , with a per-ann um cost of about 600 000 USD. Due

to increasing dem and, idle tim e reduction was there -

fore place d at the top of the list of obje ctive s to be

reached.

In orde r to ve rify the potential of the m ethodology

for non-expe rt use rs, two postgraduate students with

little practical expe rience in enterprise engin ee ring

we re chosen to apply it. In orde r to facilitate the

application of the m ethodology, a prototype software

tool for managin g the inte rmediate and m atrix-based

mode ls was deve loped by using standard PC-based

environ ments ( Microsoft Visual Basic 3.0 Pro and

Acce ss 2.0) . The IDEF0 mode l has been worked upon

by using a standard editing tool ( Design / IDEF by

Metasoftware Co.) . The `As-is’ m odel ( figure 6 shows

the A0 diagram of the IDEF0 mode l) was com ple ted in

three weeks, wh ich is much shorte r than the tim e

required by the traditional SADT methodology; above

all, shorte r than the standard period usually required by

E’ s innovation staff. Afte r its deve lopment, the `As-is’

m ode l was validated by department m anagers and

workers.

The prototype software facilitated the proce ssing of

the large am ount of in form ation availab le in the

database by allowin g flex ible que rie s and m atrix

clustering ( the we ll-known RO C algorithm was used

for this purpose , King 1980) . Th is analysis high ligh ted

the m ain problems of the departm ent, pointing out

areas of ine fficiency in in form ation managem ent and

proce ssing.

In the following two we eks, and on the basis of the

previous analysis, the `Should-be ’ mode l and m igration

plan we re prepared. Figure 7 shows the A0 diagram of

th is model. It is easy to notice that the most sign ificant

innovation in troduced was to separate line activitie s

( i.e . moulding and control) from staff activitie s ( i.e .

problem-solving and production plann ing activities) .

This separation was obtained by assigning staff activitie s

to a new team made up of expe rienced workers; in the

`As-is’ mode l, such workers we re involve d full tim e in

M. Can tamessa and E. Paolu cci426

Figure 7. `Should-be ’ A0 diagram of the case study.

line activities, so that the ir contribution to department

problem solving was e rratic and ill-structured. Expected

improve ments of the proposed work organ ization were

the following:

( 1) simplification of line activitie s and the acknowl-

edgem ent of problem-solving activitie s’ re le -

van ce ;

( 2) more e ffective problem -solving proce sses;

( 3) reduced equipm ent idle times, as a consequence

of m ore efficient line activitie s and decision

proce sses;

( 4 ) in c re ase d e xch an ge rate of com pe te n cie s

am ong workers with differen t specialtie s.

The Migration Plan was defined by comparing

the `As-is’ and `Should-be ’ m ode ls; the plan ( figure

8) m ain ly contain s organ izational and workflow-

re lated change s, and only one IT-re lated innovation

requiring minor inve stment. E’ s manage m ent has

approved it, and the plan has bee n im plemented. A

first asse ssment of re sults was made four m onths

afte r the Migration Plan im plementation start-up. In

that short period, equipm ent idle tim e has already

d e c re ase d by 30% , with e stim ate d savin gs of

200 000 USD per year.

6. Conclud ing rem arks

Th is paper brie fly discusses some issues in the fie ld

of en terprise mode lling and engin ee ring, outlining

the ir re levan ce within the managem ent of organ iza-

tion al an d tech n ological in novation in SMEs. In

Enterprise modellin g in SMEs 427

Migration Plan

Changes in organizational structure

· Dies are the scarce resource of the department, and planning their utilization requires a large amount of information andknowledge which is difficult to structure, since it changes very quickly and is owned by different persons.

Þ A new `Dies and Problems’ (DP) team is to be introduced, consisting of the responsible for die management, the diewarehouseman, process and tooling engineers. The task of this group is the retrieval, processing, storage and maintenance ofinformation concerning technological and organisational problems connected to dies.

· The responsibility of procedures concerning shift changeover is split between shift foreman and other departmental managers;this authority overlap causes conflicts and problems in product quality.

Þ The role of shift foremen will be removed, and shift changeover will be directly managed by operator team leaders of the endingand beginning shift.

· The enlargement of responsibilities given to operator team leaders induces new potential organizational conflicts.Þ The increased autonomy of operator team leaders will be balanced by increasing the plant manager’s line authority.

Changes in work-flow procedures

· The die warehouseman is involved in too many activities; he is often late in delivering required dies, increasing equipment idletime.

Þ Clerical activities connected to warehouse management will be accomplished directly by operators asking for dies.

· As consequence of the absence of required information, and of fragmentation in authority allocation within the department,production plans are often incompatible with molding technological constraints.

Þ Production schedules will be discussed among the plant foreman and the DP team.

· New-product pilot runs cause many conflicts in production activity control.Þ Production planning will give the required resources to new-product pilot runs and will transmit results to the DP team

· Set-up time must be reduced to improve shop-floor flexibility and reduce lot size.Þ Activities related to die change (including machine cleaning, loading, etc.) will be jointly executed by all workers involved.

Changes in Information System

· Production activity control isn’t currently supported by any software, this is preventing integration with the company’s MRPsystem.

Þ A new software application for production planning in the department is to be developed. The main expected features are:¨ to integrate department production activity control with the company’s MRP system;¨ to support the processing of daily department production plans;¨ to improve the availability of sharp information ion production activity control.

· Production flow must be controlled more closely.Þ A person will be dedicated full time to monitoring production flow, die availability, and coordination with internal and external

customers.

Figure 8. Migration plan proposed for the case study.

particular, special attention is cast upon methodologie s

that may be easily and e ffective ly adopted by SMEs. The

proposal m ade in th is pape r m ay be seen as a revision of

the wide ly-known SADT approach , whose objective is to

dramatically reduce the deve lopment lead-time of the

mode l, to make it exem pt from subjective vie wpoints, as

much as possible , and increase the ease of proce ssing

in formation con tained in it. Lead-time shorten ing

reduces the amount of re sources reque sted by m ode l

deve lopm ent and analysis, and makes its m ain tenance

easie r. The proposed methodology has been succe ss-

fully applied in a medium-sized enterprise , supporting

its application with a software tool designed for the

required data collection and analysis tasks. A furthe r

step will be the integration of these two package s in

order to allow transparent exchange of in form ation

between them .

Acknowled gm ents

The authors wish to thank G. Moretti and S. Ruffini

for the ir precious work in te sting the methodology.

Thanks are also due to Mr P. Aragn o for his support in

carrying out the case study in com pany E.

Re fe rence s

AGUIAR, M. W. C. and WESTO N, R. H., 1995, A mode l-drivenapproach to enterprise integration. International Journal of

Computer-Integrated Manufacturing, 8, 210 ± 224.

AMICE, 1993, CIMOSA: Open System Architecture for CIM

(Be rlin: Springer) .ANG, C. L., LUO , M. and GAY, R. K. L., 1994, Deve lopment of a

knowledge-based manufacturing mode lling system basedon IDEF0 for the metal-cutting industry. International Journal

of Production Economics, 34, 267 ± 281.

BILLO , R. E., RUCKER, R. and PAUL, B. K., 1994, Three rapid and

effective requirements de fin ition mode lling tools: evolvingtechnology for manufacturing system investigations. Inter-

national Journal of Computer Integrated Manufacturing, 7, 186 ±199.

BRANDIMARTE, P. and CANTAMESSA, M., 1994, Methodologie s forde signing CIM systems: a critique. Computers in Industry, 25,

281 ± 293.BROWNE, J., SACKETT , P. J. and WORTMANN, J. C., 1995, Future

manufacturing systemsÐ Towards the extended enterprise.Computers in Industry, 25, 235 ± 254.

BUSBY, J. S. and WILLIAMS, G. M., 1993, The value andlim itations of using process m ode ls to describe the

manufacturing organization. International Journal of Produc-

tion Research, 31, 2179 ± 2194.

CEN TC310 WG1, 1994, An evaluation of CIM mode llingconstructs. Evaluation report of constructs for views accord-

ing to ENV 40 003. Computers in Industry, 24, 159 ± 236.

COLQ UHOUN, G. J., BAINES, R. W. and CROSSELY, R., 1993, A stateof the art review of IDEF0. International Journal of Computer-

Integrated Manufacturing, 6, 252 ± 264.COLQ UHOURN, G. J., BAINES, R. W. and CROSSELY, R., 1996, A

composite behavioral mode lling approach for manufactur-ing enterprises. International Journal of Computer-Integrated

Manufacturing, 9, 463 ± 475.CUTTS, G., 1991, SSADM Structured Systems Analysis and Design

Methodology( Oxford: Blackwell Scientific) .DAVENPO RT, T. H. and SHORT, J. E., 1990, The new industrial

engineering: information technology and business processrede sign. Sloan Management Review, 11, 11 ± 27.

DEVEREUX , S., SMITH, P. and WOO D, D., 1995, A survey of the useof de sign methodologie s for implem enting change in

manufacturing companies in the United Kingdom. Interna-

tional Journal of Manufacturing System Design , 1, 51 ± 58.

DOUMEINGTS, G., 1989, GRAI approach to designing andcon trolling advanced manufacturing system in CIM envir-

onment. In S. Y. Nof and C. L. Moodie ( eds) Advanced

Information Technologies for Industrial Material Flow Systems

(Berlin Heidelberg: Springer) , pp. 196 ± 214.

DOUMEINGTS, G., VALLESPIR, B. and CHEN, D., 1995, Methodolo-gies for de signing CIM systems: a survey. Computers in

Industry, 25, 263 ± 280.

FUNG, R. Y. K., 1993, A structured analysis of the management

of high complexity jobbing production. Proceedings of the IX

CAPE Conference, Nanjing, China, July 1993 (China: AviationIndustry Press) , pp. 23 ± 28.

GOVINDARAJAN, V. and SHANK, J. K., 1992, Strategic Control

Management: tailoring controls to strategies. Journal of Cost

Management, Fall, 14 ± 24.

H AMMER, M., 1990 , Re -e n gin e e ring work: Don ’ t au to-mate , obliterate . Harvard Business Review, July ± August,

104 ± 112.

HOSTNIK, C. J., BILLO , R. E. and RUCKER, R., 1985, Making the

most of structured analysis in manufacturing informationsystem design : application of icons and cycle time . Computers

in Industry, 16, 267 ± 278.HOWARD, R., 1990, Can small business he lp countries com-

pe te?. Harvard Business Review, January ± February.JORYSZ, H. R. and VERNADAT, F. B., 1990, CIM-OSA part 1: total

en terprise mode lling and function view. International Journal

of Computer-Integrated Manufacturing, 3, 144 ± 156.

KING, J. R., 1980, Machin ing-component grouping in produc-tion flow analysis: an approach using a Rank O rder

Clustering algorithm . International Journal of Production

Research, 18, 213 ± 232.

KOONCE, D. A., JUDD, R. P. and PARKS C. M., 1996, Manufactur-ing systems engineering and design: an intelligen t, multi-

mode l, in tegration arch itecture . International Journal of

Computer-Integrated Manufacturing, 9, 443 ± 453.

KUSIAK, A., LARSO N, T. N. and WANG, J. R., 1994, Reengineeringof design and m anufacturing processes. Computers in

Industrial Engineering, 26, 521 ± 536.LEIFER, R. and BURKE, W. J., 1994, Organizational activity

analysis: a me thodology for analyzing and improvingtechnical organization. IEEE Transactions on Engineering

Management, 41, 234 ± 244.MARCA, D. A. and MCGOWAN, C. L., 1988, Structured Analysis and

Design Techn ique ( New York: McGraw Hill) .

M. Can tamessa and E. Paolu cci428

MAYER, R. J., CULLINANE, T. P., DEWITTE, P. S., KNAPPENBERGER , W.B., PERAKATH, B. and WELLS, M. S., 1992, Information

Integration for Concurrent Engineering ( IICE) IDEF3Process Description Compute r Method Report. Armstrong

Laboratory, Wright-Patterson Air Force Base , O hio 45433,AL-TR-1992-0057.

MCSWINEY, J., 1995, BPR for SMEs. In J. Browne , and D.O’ Sullivan ( eds) Re-engineering the Enterprise ( London: Chap-

man and Hall) .OFFO DILE, O. F., MEHEREZ, A. and GRZNAR, J., 1994, Cellular

manufacturing: a Taxonomic Review Framework. Journal of

Manufacturing Systems, 13, 196 ± 220.

PORTER, M. E., 1985, Competitive Advantage (New York: The FreePre ss) .

VERNADAT, F., 1993, CIMOSA: Ente rprise mode lling andenterprise integration using a proce ss-based approach.

Proceedings of the JSPE-IFIP WG 5.3 Workshop on The Design of

In formation In fra stru ctu re Systems for Man u factu rin g

(DIISM’93), Tokyo, Japan , November 1993, pp. 65 ± 79.WILLIAMS, T. J., 1992, The Purdue Enterprise Reference Architecture

( Re search Triangle Park, NC: Instrume nt Socie ty ofAmerica) .

WILLIAMS, T. J., BERNUS, P., BROSVIC, J., CHEN, D., DOUMENINGTS, G.,NEMES, L., NEVINS, J. L., VALLESPIR, B., VLIETSTRA, J. and

ZOETEKO UW, D., 1994, Arch itectures for integrating manu-facturing activities and enterprises. Computers in Industry, 24,

111 ± 139.

Enterprise modellin g in SMEs 429