Holonic User Driven Methodologies and Tools for ...

Holonic User Driven Methodologies and Tools for Simulating Human Organizations Emmanuel Adam

Christophe Kolski

Emmanuel Vergison

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René Mandiau

LÂMIH URA CNRS 1775, Université de Valenciennes et du Hainaut Cambrésis, Le Mont Houy B.P. 311 F 59304 Valenciennes Cede Rue de Ransbeek. 310 B 1120 Bru.xelles E-mail: E-mail: E-mail: E-mail enunanuel.vergison~sOIVay.com kolski@univ_valenciennes.fr [email protected] [email protected] SOL VAY Research and Technology, SOLVAY S.A. -

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The systems under consideration in this paper are time dependent, user-driven and supposed to be structured as a flexible hierarchy (holarchy) of cooperating human and/or computerized agents dealing with documents (producing, sending, receiving, updating, archiving,...).

KEYWORDS Enterprise Modelling, Holonic Systems, SADT, Petri Nets, mufti-agent systems ABSTRACT

Cooperation is looked at as a way to optimize the document flows within the system and between the agents, keeping the quality of the processed documents at a high standard and meeting customer (end-user) satisfaction.

Enterprise Modelling, viewed as a modelling exercise of all/part of the organization structure in order to obtain a better understanding of its working mechanisms and performance, is a widely accepted practice. Rather new today, however, is the need for modelling frameworks capable of simulating business/management activities which depend much more drastically on demanding organization needs, severe time constraints and decisivc human factors.

The methodology developed in titis paper, so called HAS for Holonic Administrative Systems, is aimed at businessfadministrative activities. It is largely underpinned by the work of Arthur Koestier who. 26 vears ago. studied the essential structure and the stability of complex social systems facing internal andlor external disturbances or perturbations : Holonic Systems (Koestler 1969). These systems will be introduced in the next chapter.

In this paper. we show how to couple the Holonic Concept developed by A. Koestier for social organizations, Software Engineering Techniques like OMT, SADT, OSSAD, and Petri Nets, to get a user friendly and computerizable way for simulating processes involving both technical and human facets.

We then present the HAS architecture which basicaliy consisis of two hierarchically dependent activity layers expressing two different levels of granularity within the system.

INTRODUCTION

Traditionally. Enterprise Modelling encompasses areas such as technical or business process modelling and optimization, system design, production planning, computer-driven manufacturing, shop floor control systems. and is essentiallv based on rather classical mathematics, statistics and Infonnation Technology techniques, methods and tools.

The highest and more general level of description is denved from weIl known Software Engineering techniques: OMT (Object Modelling Technique) (Rumbaugh et ai. 1991), SADT (Structured Analysis and Design Technique CRoss 1977) (IGL 1989) and OSSAD (Office Support Analysis and Design) (Dumas and Charbonnel 1990).

Over the last decade, structural changes in the world definitely impacted industrial orgaxuzation practices and business. Concepts such as Virtual and Distributed Enierprise/Organization and Holonic Systems are now emerging and they generate new research and modelling perspectives.

The use of Software Engineering originated methods that could be used in Systems Design is thoroughly discussed in (Adam and Kolski 1998).

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The iower and more detailed level of activity description is based on the Petri Net concept (Petri 1962). The reasons for this choice are threefold:

Another trend is the more explicit involvement of Human Issues within the process of Enterprise Modelling (Fraser and Macintosh 1994). This is a consequence of the need today to provide decision makers with tools and methods capable of simulating complex processes involving people, in a rapidly moving and changing context.

• Petri Nets are very flexible and well suited for niodelling time-dependent detailed processes • in iheir essence, they are quite close to mie based kno~~’Iedge production systems and thus quite user-friendiy • the are underpinned by a robust mathen~atical theoiy which renders computerization easier

The HAS methodology originates in real processes and is now being iniplemented within the SOLVAY Patent PhD Student whose thesis is joint)y sponsored by the ~‘Nord - Pas de CaIais Region (France) and SOL VAY S.A

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These methods, generall~ issued from (lie CSCW paradigm (CSCW stands for Computer Supported Cooperative Work). essentially focus on solutions to specific probiems like designing and installing a distributed editor or a video conference system (Connolv and Edmonds 1994).

Department and Library. Not only were the end-users deeply involved in the exercise, but thev aiso played a key role when the specification list for a computerized siniulator ~~as devised. This simulator based on the Petri Net Concept is written in Visual C++. ~vorks on a PC and is presently under test.

In our opinion, if CSCW is very well suited to solve such problems where, in general, just a few peopie are interacting in a rather isolated process, it is flot suitable for large complex systems design.

HOLONIC SYSTEMS Twenty six years ago, the Hungarian writer Arthur Koestier who ~vas studying living organisms and social organizations discovered that in real life. parts or wholes cannot be looked on as absolutes. He introduced the concept of Holon, originated from the Greek word holos, meaning whole, and the suffix on suggesting a part like in “proton

The HAS architecture, in turn. considers a system as a whole, made of more or less loosely coupled processes sharing common goals. T3pical processes in our case are: patentability studies, technical advice processes. trade-mark studies or technological watches. In contrast (o traditional hierarchical systems (Fig. 1) where goals are commu.nicated down in the form of tasks, from the top level to the next lower one, in HAS systems, communication takes the forrn of sub-goals to the next Iower level sub-processes (holons) as shown in Fig. 2.

A holon, as devised by Koestier, is supposed to be a stable autonomous and cooperative part of a Iarger organization or whole. Srabilitv means that the holon can face and properly

react when subjected to severe requests or perturbations. Autonomv refers to the holon’s self-management ability

when it has to react against disturbances. Cooperalion means that holons are standing together with other holons or holon layers, and capable of working on conimon projects and goals.

in the framework of an international collaborative initiative called “Intelligent Manufaciunng Systems” (IMS), a project consortium, the Holonic Manufacturing Systems, already translated Koestler’s ideas into a set of appropriate concepts for manufacturing industries (Van Brussel et al. 1996) (Hôpf 1996) (Vaikenaers and Van Brussel 1996). The underlying intention is to consider Holonic Manufacturing as one paradigm for the facto~y of the future.

Figure I. Traditiona! system architecture.

We took great advantage of the IMS work in order to port Koestler’s paradigm into administrative systems which rather like the manufacturing ones encompass svstem architecture, information structures and flows, w’ork organization, cooperation between agents as well as hardware issues. Figure 2. Holonic Ad,ninistrauve System architecture

THE HAS ARCHITECTURE

strasghr une main data flow dotred une minor data flow (restricted to outside commun,cat,ons)

Processes as well as sub-processes within a complex administrative system rely on people prescribed tasks and activities (the way tasks are performed), procedures (legal or local), ail factors which in one or another way have to deal with and handle documents.

The HAS Modelling Methodology The choice of modeliing methods and tools for designing complex administrative systems largely relv on their ability (o deal with various types of documents. with dynamic parallel treatment, with deferred actions, interrupts, synchronous and asynchronous information flows.

The document Iooked on as a structured entity made of information chunks is the key concept around which everything articulates. Methodologies for designing Document Systems already exist but they generaily do flot provide anv solution for managing contextual document information processed in paralici. 58

Document strucluring One of our firsi need was to dispose of a method for designing a document system. After a comparative study on existing abject models such as OOA (Shlaer and Mellor 1992) and OOD (Coad and Yourdon 1991), we opted for the so-cailed OMT (Object Modeliing Technique) methodology from which we took the abject mode!.

OSSAD, the Office Support and Analysis Design method. This processing mode! provides a detailed viei~’ of the process (Fig. 5) and constitutes a preliminars step towards system specification. Aà,~ru~,.t,w Oq~c.

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Modelling human activities and informaiion flows Human activities i~ithin HAS essentiallv consist of production, operations on, and management of documents. After having tested several activitv models. we found that the mosi attractive one for representing activities was the wide!)’ accepted SADT which proved to be well suited to h7uman activitv modelling (Abed and Angue 1994).

Figure 5.Subser ofa Paient Deporimenr Proccss

Modelling ihe system dynamics The various frameworks implemented up ta now give a fairly good graphic representation of the whole system, of its organization and of ~ts static working mechanisms. They do flot however ailow for time-dependent activity modelling and they cannot efficiently manage interrupts, parallelism or s nchronization (Abed and Angue 1994).

SADT, at the same time, provides a means to obtain an overali picture of the svstem, a clear view of the operations on documents and of the document exchanges bet~i’een players.

We turned ta Petri Nets to achieve these goals. A Petri Net is basicaliy a graphic representation sustained by a robust mathematical theoiy, aimed at modelling systems where the concepts of events, occurrence of events, event synchronizationJasynchromza~ion or parallelism play an important raie.

The underlving concept ive choose ta structure the mode! is the position of the actors i~’ithin the system. Figure 4 below gives an example on how players in the system are represented b)’ rows listed top down and ranked in decreasing level of position.

A Petri Net, as shown in the examples below extraced from David and Alla (David and Alla 1989), is composed of places (P0, Pi, ...), transitions (TO T5), events (transition passing conditions) and token “place to place” passing mies. .~

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Figure 4. Exampte ofan activay mode!

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The token in POis duplîcaaed inro PI andP3 when the ea’ent associateS wirh TO occurs. In order to reach P5. bath places P2 and P4 need ta contain o token.

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The latter make explicit the links between sub-entities. identify their goals and guarantee the stability of the whole system. They must also be defined in such a way that sub-entities dispose of a self-management capability. An exampie is shown in Fig. 9.

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Figure 7. Synchronizatson in Petri nets Passang transition T! as on!;’ possible when the associated event occurs and P3 conlains o token.

There are many ~‘ariants of Petri Nets and when we had 10 make a “best choice’ for our HAS needs, we finally opted for a parameterized object net allowing for interrupr handiing (Agimont 1996) (Gracanion 1994). In such a net, a place represents a raie whilst tokens represent either actors playing these raies or documents.

A simulator has been built in order to follow dynamicaliy modelied processes and learn about them. It has been developed in Visual C++ on a PC station and is presently under intensive test (Gransac 1997). The use of this simulator makes it casier 10 specii~’ holons, check their behavior and their capability to cooperate. From the end-user point of view, it clarifies the process(es) in which they are involved, and cleariy identifies their individuai role and their links to other people andlor entities.

On the one hand. the object concept ailowed us 10 add meaning to tokens and, on the other. parametrzation rendered the net description casier and more readable (Fig.8).

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~ (c) Figure 8. Example ofParameterazed Petri net ~‘aJ This place. corresponding ta o workspace (related to o rote). includes one document and one secretary worL~ng on that document. (b) In rhis place. the phone rings. The secretaty is inerrupted (transition I as Jlred) and her status changes. The document ii kept in place. A~otrot,oe ~aff

(c) The cati ends (transition 3 as fired); the secretaiy returns to her work.

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Transition 2 as actavared when the secretary as moving from one ta ana:her acuvuy. her work being compleied normaIlj~

Activating mies are associated with each parameterized place; they depend on the type of document and the kind of people in the place.

CONCLUSIONS AND PERSPECTIVES

Two sorts of ruies are considered : those which are specific 10 a persan (personal rules) and those (organisational) which are imposed bv the system.

In this paper, we developed an easy to implement and user-friendly methodology supported by tools for simuiating business/administrative systems.

Personal rules express the way human players work whilst organisationai rules express svstem prescribed tasks and the system internai governing rules.

It is based on the Holon concept which seems well suited for systems where cooperation between humans plays a decisive role. 60

This methodology is now Jargely implemented and is being validated in the field, on a rather large scale with a deep end-user involvement.

coordination in intelligent systems”. IEEE Transactions on Systems. Ma~z and Cybernetzcs, 24:1483-1497

The next steps in our initiative are twofold: first of ail we will consoiidate our approach by developing open and rigorous Return on Experiment checks and, in parallel,

Net Simulator Contribution to the study of Complex Business/Administrative Systems”, (in French), DESS Technical Report University of Valenciennes & SOLVAY SA. Hôpf M. (1996), “Holonic Manufacturing Systems (HMS)

we will set up specifications for a more systematic and as generic as possible computerization scheme in order to ex-tend the use of the methodology ta other sectors of activity.

http://w’.~w.ncms.orgi1ims/public/holo2.html I.G.L. Technology (1989). “SADT, un coninsuniquer”. Eyrolles, Paris.

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•

Gransac J. (1997) “Construction of an Object Oriented Petri -

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lie Basic Concept and a Report ofIMS Test Case 5”, Internet

Koestier A. (1969) “The Ghost in ACKNOWLEDGEMENTS

langage

pour

tue Machine”, Arkana

Books, London. Notte D., (1996), “The Patent Department : Domain study”, (in French), SOLVAY internai report, Ergodin.

As alreadv mentioned, the HAS methodology originated within the Patent Departinent where people have aiways been vezy supportive and helpftul from the early start of the project. We are grateful to them.

Petri C., (1962), Kommunication mit Automaten. Ph. D. Dissertation, University of Bonn, 1962. Ross D.T. (1977) “Structured Analysis : a language for communicating ideas”, IEEE Transactions on Software Engineering, vol. SE-3, 1, January.

We are also specially indebted to previous work by D. Notte (None 1996) and P. Carrere (Carrere 1996) which facilitated the simulator specifications exercise.

Rumbaugh J. Blaha M., Premerlani W., Eddy F., Lorensen W. (1991). “Objecr-orienied modeling and design PrenticeHall. “.

References

Shlaer S. and Mellor S.J., (1992), “Objeci L~fecvcles, Modeling the World in stales “, Yourdon Press.

Abed M. & Angué J-C. (1994), “A new Method for Conception, Realisation and Evaluation of Man-Machine Interfaces”, Procccdings IEEE. Systems and C~ybernerics, san Antonio 2-5/10

Valckenaers P. and Van Brussel H. (1996), “Intelligent Manufacturing Systems Technical Overview”, Internet -

http://i’.”.~w.ncms.org/hnis/public/hms_tech.htrnl

Adam E. & Kolski C. (1998) “The usage of Software Engineering methodologies in Process Design : a comparative studv.” Subnzitred to Sixrh European Conference on Information Systems, Aix-en-Provence, June 4-6.

Van Brussel H., Valckenaers P., Wyns J., Bongaerts L., Detand J. (1996), “Holonic Manufacturing Systems and Fini”, JT and Manufacturing Partnerships, J Browne et al. (Eds), IOS Press

Agimont G., Le Strugeon E., Mandiau R., Libert G. (1996) “Parametrized petri nets for organizational simulation and systems design. Proceedings of the Second International Conference on lime Design of Cooperatii’e Systems (‘COOP’96,l,

COOP Group (Ed.), Juan-les-Pins, France, 12-14 June.

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Carrere P., (1996), “Production, gestion et diffusion électronique de documents, Ré-ingénierie des processus dactivités d’un département de Propriété Industrielle”, DEA Technical Report University ofCompiègne & SOLVAY SA. -

Coad P., Yourdon E. (1991). Object-oriented design. Prentice Hall. Connolv J.H. and Edmonds E.A. (Eds.), (1994),

CSCW and

Art~ficial Intelligence. Springer-Verlag, London.

David R. & Alla H., (1989) Du Grafcet au réseaux de Perri. Hermes, Paris. Dumas P., Charbonnel G. (1990), La méthode OSSAD, pour maîtriser les technologies de î ‘information. Tome 1 principes. Les éditions d’organisation, Paris. Fraser J. & Macintosh A. (1994) (Survey Editors) “Enterprise State of lie Art Survey’, Enterprise DTI ISIF Project N° 8032, University of Edinburgh -

Gracanion D., Srinivasan P., Valavanis K.P., (1994) “Parameterized Petri nets and their application to planning and

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