C. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In Proceedings of Conference on Organizational Computing Systems, 1995.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....changes, by allowing simple modifications to the schema followed by a given instance as well as execution state modifications. Recently, some approaches to handle dynamic changes have been presented in the literature by the workflow research community. One of the first contributions come from [2], that defines a correctness criterion for instance migration, based on the definition of the set of all valid node sequences: a change is correct if the execution sequence could have been obtained with the new schema. The paper, however, introduces a simple workflow model and restricts to a ....

S. Ellis, K. Keddara and G. Rozenberg, Dynamic Change within Workflow Systems, Proceedings of (COOCS '95), Milpitas, California, 1995.

....languages such BPEL4WS, BPML, XLANG, WSFL, WSCI, etc. have adopted most workflow concepts. Despite its promise, many problems are encountered when applying workflow technology. As indicated by many authors, workflow management systems are too restrictive and have problems dealing with change [2,4,7,12,20]. Many workshops and special issues of journals have been devoted to techniques to make workflow management more flexible (e.g. 2,4,20] Most of the research in this area is devoted to techniques to increase the flexibility either by allowing for ad hoc changes (as reflected by workflow ....

.... more flexible (e.g. 2,4,20] Most of the research in this area is devoted to techniques to increase the flexibility either by allowing for ad hoc changes (as reflected by workflow management systems such as InConcert [18] or by providing mechanisms to migrate cases and evolve workflows [7,12]. In this paper we take a different perspective with respect to the problems related to flexibility. We argue that many problems are resulting from a discrepancy between workflow design (i.e. the construction of predefined workflow models) and workflow enactment (the actual execution of ....

C.A. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In N. Comstock and C.A. Ellis, editors, Conf. on Organizational Computing Systems, pages 10 - 21. ACM SIGOIS, ACM. Milpitas, California, 1995.

....dynamic workflows. Such systems must be uniquely sensitive to a rapidly changing process execution triggered by collaborative decision points, context sensitive information updates, and other external events. The majority of current work addresses relevant issues at modeling and language levels [24, 36, 45, 53, 57, 70] while the relevant issues involving organizational changes appear in [24, 38] A particularly different approach to supporting adaptive workflow (capable of reacting to the changes in local rules and other conditions) has been developed using the notion of migrating workflows) 19] Related ....

....triggered by collaborative decision points, context sensitive information updates, and other external events. The majority of current work addresses relevant issues at modeling and language levels [24, 36, 45, 53, 57, 70] while the relevant issues involving organizational changes appear in [24, 38]. A particularly different approach to supporting adaptive workflow (capable of reacting to the changes in local rules and other conditions) has been developed using the notion of migrating workflows) 19] Related issues of integrating workflow or coordination technologies and collaborative ....

C. Ellis, K. Keddara, and G. Rozenberg, "Dynamic changes within workflow systems," in Proc. of the Conf. on Organizational Computing Systems (COOCS'95), 1995.

....work item is executed by a single worker. Hence, distributed collaborative work in virtual project communities finds almost no support by WfMS. Groupware [3, 6] on the other hand, typically does not contain any knowledge or representation of the goals or underlying business processes of the group [4, 5, 8, 10]. In this paper, we discuss distributed product development in a virtual project community provided by the MOTION teamwork services platform [11, 13] The contribution of this paper therefore is a scenario based discussion of process aware software engineering in distributed and mobile ....

C. A. Ellis, K. Keddara, G. Rozenberg "Dynamic Change within Workflow systems," in Proc. COOCS International Conference, Milpitas, CA, USA, 1995.

....control protocol. This protocol protects the retrieval of steps by workflows from updates of the steps by administrative transactions and controls which of the workflows can use an updated specification, and which has to stick to the old one. This way, it eliminates the dynamic change bug [9, 26], i.e. errors introduced by changing specifications of active workflows. ithin the transactions formed by the workflows each step can execute arbitrary actions (represented by dotted lines in the figure) on, e.g. an application database. Correctness of these actions with several workflows ....

....does not cause the WfMS to stop execution of running workflows, nor to delay starting new ones 4. The solution must be applicable within a system that isolates workflows with some kind of transactions and implements recovery by compensation [17] Requirements 1 and 2 are derived from [9], while number 3 is more than reasonable in a real life WfMS. Requirement 4 is mainly motivated by our specific setting, as ULTRAflow uses compensation for recovery, i.e. it performs semantically reverse actions to undo the e#ects of aborted transactions. In systems that do not rely on ....

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C. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In Proc. Conf. on Organizational Computing Systems, pages 10--22, 1995. 517, 518

....fully understand the concepts. At the moment, there are more than 200 workflow products commercially available [24] and many organisations are introducing workflow technology to support their business processes. It is widely recognised that workflow management systems should provide flexibility [7 9, 12, 16, 21, 28, 33, 36, 37, 47, 56]. However, today s workflow management systems have problems dealing with changes, e.g. new technology, new laws, and new market requirements may lead to (structural) modifications of the workflow process definition at hand. In addition, ad hoc changes may be necessary, e.g. because of ....

....(a) restart (b) proceed (c) transfer before change after = new process = old process Fig. 1. How to handle running cases do not affect running cases by allowing for multiple versions of the process, and (c) transfer: a case is transferred to the new process. The term dynamic change [21] is used to refer to the latter policy. Restarting cases causes no real difficulties except that it is often difficult to rollback the tasks that have already been executed. The proceed policy also causes hardly any problems. In fact, it is the only policy truly supported by today s commercial ....

C.A. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In N. Comstock, C. Ellis, R. Kling, J. Mylopoulos, and S. Kaplan, editors, Proceedings of the Conference on Organizational Computing Systems, pages 10 -- 21, Milpitas, California, August 1995. ACM SIGOIS, ACM Press, New York.

....the workflow process Workflow processes may change on the fly as a result of changing laws, reengineering efforts, etc. This often leads to the situation where cases (workflow instances) have to migrate from the old workflow process to the new workflow process. As was first demonstrated in [25] this may lead to all kind of anomalies (e.g. deadlocks, livelocks, etc. Consider a case that is moved from a process with A and B in parallel to a process with A and B in sequence. If the case is in a state after executing B but before executing A, there is no corresponding state in the ....

....etc. Consider a case that is moved from a process with A and B in parallel to a process with A and B in sequence. If the case is in a state after executing B but before executing A, there is no corresponding state in the sequential process. This phenomenon is known as the dynamic change bug [25]. In [8] it is demonstrated that these anomalies can be avoided if the old and the new process are in a subclass superclass relation. In [16] the problem is tackled for workflow processes without loops. Despite these partial solutions, the more general problem remains unsolved. 8. How to ....

C.A. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In N. Comstock, C. Ellis, R. Kling, J. Mylopoulos, and S. Kaplan, editors, Proceedings of the Conference on Organizational Computing Systems, pages 10 -- 21, Milpitas, California, August 1995. ACM SIGOIS, ACM Press, New York.

....to continuous change. At the moment, there are many workflow products commercially available and many organizations are introducing workflow technology to support their business processes. A critical challenge for workflow management systems is their ability to respond effectively to changes [4,7,10,11,12,15,18,26,28,32]. Changes may range from ad hoc modifications of the process for a single customer to a complete restructuring for the workflow process to improve efficiency. Today s workflow management systems are ill suited to dealing with change. They typically support a more or less idealized version of the ....

....addition of the horizontal dimension allows for the design and enactment of many variants of a workflow process. However, it is not sufficient to support the design and enactment. There are two additional issues that need to be dealt with: 1) management information [32,33] and (2) dynamic change [7,11,12]. In spite of the existence of many variants of one process, the manager is interested in information at an aggregate level, i.e. management information which abstracts from small variations. The term dynamic change refers to the problem of handling old cases in a new process, e.g. how to ....

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C. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In N. Comstock and C. Ellis, editors, Conf on Organizational Computing Systems, pages 10 - 21. ACM SIGOIS, ACM, Aug 1995. Milpitas, CA.

....support. At the moment, there are more than 200 workflow products commercially available and many organizations are introducing workflow technology to support their business processes. A critical challenge for workflow management systems is their ability to respond effectively to changes [ 11,12,13,17,20,21,27,30,37,41,43,49]. Changes may range from ad hoc modifications of the process for a single customer to a complete restructuring for the workflow process to improve efficiency. Today s workflow management systems are ill suited to dealing with change. They typically support a more or less idealized version of the ....

....addition of the horizontal dimension allows for the design and enactment of many variants of a workflow process. However, it is not sufficient to support the design and enactment. There are two additional issues that need to be dealt with: 1) management information [49,50] and (2) dynamic change [13,20,21]. In spite of the existence of many variants of one process, the manager is interested in information at an aggregate level, i.e. management information which abstracts from small variations. The term dynamic change refers to the problem of handling old cases in a new process, e.g. how to ....

[Article contains additional citation context not shown here]

C.A. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In N. Comstock and C. Ellis, editors, Conf. on Organizational Computing Systems, pages 10 - 21. ACM SIGOIS, ACM, Aug 1995. Milpitas, CA.

....above, current workflow and personal systems independently manage each workflow and each user s schedule table; thus, a resource allocation mechanism is needed. This is a dynamic workflow control problem. There have been some research results in the area of dynamically changing workflow processes[2, 6, 11, 17, 22]. In such research, dynamic or incremental changes of workflow process definitions are the main concern. In [3] it deals with problems that occur when a workflow process definition is changed while its instances are alive. However, we are trying to solve another kind of dynamic problem: dynamic ....

Ellis, C., et al.: Dynamic Change Within Workflow Systems, in Proceedings of COOCS'95, ACM (Aug. 1995), pp. 10--21

....system maintaining a unique context in order to accompany the user while her attention switches from the routine to the solution of the occurred breakdown and back. Workflow Management Systems are composed of two basic components: the Workflow Model and the Workflow Execution Module (see also [Ellis Keddara 1993]) The former is devoted to supporting the designer of a workflow support system, while the latter executes it when a workflow is started by any authorized user. Despite their growing success, already existing Workflow Management Systems exhibit severe limitations in both their Workflow Model and ....

....the designer of a workflow support system, while the latter executes it when a workflow is started by any authorized user. Despite their growing success, already existing Workflow Management Systems exhibit severe limitations in both their Workflow Model and Workflow Execution Module (see [Ellis Keddara 1993, Abbott Sarin 1994] 1. Exception handling mechanisms are basic features of Workflow Management Systems, but generally either they are too restrictive with respect to the needs of their users or they are too complicated both with respect to the performances of the Workflow Execution Module and ....

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Ellis, C., Keddara, K. Dynamic Change within Workflow Systems. University of Colorado Technical Report, July 1993.

....by different actors or roles. The traditional separation between dynamic adaptive and static production workflow refers to whether changes to the definition of a workflow type can affect running workflow instances. At the same time, researchers have suggested different approaches. Ellis, et al. [19] point to the need for the specification and execution modules of workflow systems to be tightly interwoven, Haake and Wang [27] to the need for supporting processes with emerging structure. Design and software engineering are mentioned as examples of such work processes [32] Our aim is to ....

Ellis, C., Keddara, K. and Rozenberg, G. Dynamic Change Within Workflow Systems, COOCS' 95: Conference on Organizational Computing Systems, Milpitas California, USA, 1995.

....focus of this paper. From the viewpoint of GADB, BPT is a very important source of data. BPT log will be used for later reengineering. 5.2 Business Process Reengineering There are some research results in the BPR (Business Process Reengineering) field. Some of them are on the reengineering model[3, 1, 7], some applied knowledge technologies [10] In ActionWorkflow[16] and Regatta[21] reengineering is represented as incremental re definitions of a process definition. Borghoff discussed how two kinds of business processes can co exist, those processes before and after the reengineering[2] In our ....

Ellis, C., Keddara, K., and Rozenberg, G. : Dynamic Change Within Workflow Systems. Proc. of Conf. on Organizational Computing Systems '95, ACM (1995) 10--21

.... environment to accomplish a given task [11] A workflow system is meant to improve the process throughput, to promote a better use of resources, and to enable efficient process tracking [24] Moreover, since workflow applications are subject to frequent changes caused by the business environments [6], flexibility and adaptability are required in different directions, from dynamic evolution of existing coordination policies to proper reactions to unpredictable situations [13] In the VE case, WFMS have typically to face the issue of distribution that is, to coordinate a multiplicity of ....

C. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In ACM Conference on Organizational Computing Systems, pages 10--21. ACM, 1995.

.... work also constitutes, we believe, a substantive and novel contribution to previous efforts on exception handling, which have been pursued in the context of workflow (Kunin 1982; Kreifelts and Woetzel 1987; Auramaki and Leppanen 1989; Karbe and Ramsberger 1990; Strong 1992; Mi and Scacchi 1993; Ellis, Keddara et al. 1995; Klein 1998) manufacturing control (Parthasarathy 1989; Katz 1993; Visser 1995) model based fault diagnosis (deKleer and Williams 1986; Krishnamurthi and Jr. 1989; Birnbaum, Collins et al. 1990; Friedrich, Gottlob et al. 1990) planning (Sussman 1973; Goldstein 1975; Broverman and Croft 1987; ....

....enough to allow substantial automation of the exception diagnosis process, i.e. where most or all questions are answerable by software systems. We plan to take advantage of the substantial emerging body of research of specification languages for correctness preserving workflow transformation (Ellis, Keddara et al. 1995) to address the second challenge. For further information about our work, see the Adaptive Systems and Evolutionary Software web site at http: ccs.mit.edu ases . For further information on the Process Handbook, see http: ccs.mit.edu 10 Acknowledgements The authors gratefully acknowledge the ....

Ellis, C. A., K. Keddara, et al. (1995). Dynamic Change within Workflow Systems. Proceedings of the Conference on Organizational Computing Systems, New York, ACM Press.

....differs from our approach in that no strict correctness requirements exist, e.g. modifications are allowed even if inconsistencies may result. Furthermore, no specific process schema modification operations are provided. Following, related work in the area of workflow management is considered. [5] proposes a workflow evolution approach, where workflows are modeled by special kinds of Petri nets that can be modified by replacing a subnet of an existing net by another one. A correctness criteria, defining valid workflow execution sequences, specifies which modifications are correct. However, ....

C. Ellis, K. Keddara, and G. Rozenberg. Dynamic Change Within Workflow Systems. Proc. Conf. on Organizational Computing Systems, Milpitas, USA, August 1995.

....used to support dynamically changing workflow processes or the workflow process is supported in a rigid manner, i.e. changes are not allowed or handled outside of the workflow management system. In this paper, we focus on a notorious problem caused by workflow change: the dynamic change bug (Ellis et al. 1995). The dynamic change bug refers to errors introduced by migrating a case (i.e. a process instance) from the old process definition to the new one. A transfer from the old process to the new process can lead to duplication of work, skipping of tasks, deadlocks, and livelocks. This paper ....

....p1 p3 p2 p4 p5 p6 Fig. 1. The dynamic change bug. The term dynamic change refers to the problem of handling old cases in a new process, e.g. how to transfer cases to a new version of the process. The dynamic change problem which was first mentioned by Ellis, Keddara, and Rozenberg (Ellis et al. 1995) in 1995. To discuss this problem we use the two Petri nets shown in Figure 1. For an introduction to Petri nets (Reisig and Rozenberg, 1998) we refer to Appendix A. If the sequential workflow process (left) is changed into the workflow process where tasks send goods and send bill can be executed ....

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Ellis, C., Keddara, K., and Rozenberg, G. (1995). Dynamic change within workflow systems. In Comstock, N., Ellis, C., Kling, R., Mylopoulos, J., and Kaplan, S., editors, Proceedings of the Conference on Organizational Computing Systems, pages 10 -- 21, Milpitas, California. ACM SIGOIS, ACM Press, New York.

....must be verified in accordance with the correctness properties of the modeling language being used. Significant research has been done on the conceptual specification of workflow model and provision of change operations which guarantee the (structural) correctness of the changed model [15] 16] [17], 18] Our contention is that modifying the workflow (model) should be as flexible as building a new one, as long as the changes are Family Skill Ineligible Eligible Approve Disapprove Pass Fail Reject Satisfied =75 Return Passport Application Rejected Clear Sponsors Review by ....

Ellis S., Keddara K., Rozenberg G. (1995) Dynamic Changes within Workflow Systems. Proceedings of ACM Conference on Organizational Computing Systems (COOCS 95).

....detection, propagation and reaction needs to be implemented. 5 . Evolution specially in an heterogenous enviroment, dynamic changes in the distribution of the data, availability of personel and processes, make necessary that process managers provide some sort of support for dynamic change [CG95]. One specially interesting issue is how to handle processes that are already in progress. Do they get al..l changed to the new process, or should some of them be treated di#erently, according perhaps to the phase they are in at the moment of the change Again this is an open problem that poses many ....

K.Kedara C.Ellis and G.Rozenberg. Dynamic change within workflow systems. In N. Comstock and C.A. Ellis, editors, Proceed6 ings of the Conference on Organizational Computing Systems - COOCS'95, Milpitas, California, September 1995. ACM Press.

....for realizing policies coordinating various activities as well as resources needed to perform these activities plays a central role. This need for flexible coordination mechanisms emerges from the fact that workflow applications are subject to frequent changes caused by the business environment [Ellis et al. 1995] . Flexibility and adaptability is required in different directions ranging from a dynamic evolution of existing coordination policies to proper reactions to unpredictable situations. Active object oriented database systems along with their basic mechanism of ECA rules seem to be a promising ....

.... worklist management policies coordinate the execution order of several activities inserted into the worklist of a single agent (cf. 6] in Figure 1) Worklist management policies are necessary since business processes and therefore also single activities are often subject to temporal constraints [Ellis et al. 1995] . In fact, our framework supports three basic kinds of worklist management policies that support these temporal constraints. First, as soon as a new activity arrives at a certain worklist, the execution order of existing activities including the new one is re scheduled on the basis of the ....

Ellis, C.A., Keddara, K., and Rozenberg, G. 1995. Dynamic Change Within Workflow Systems. In ACM Conference on Organizational Computing Systems, N. Comstock et al. (eds.), ACM Press, Milpitas, 10-21.

....as well as system oriented tasks. b) A posteriori flexibility (flexibility by dynamic adaptation) is provided by the change and evolution of workflow models in order to modify workflow specifications on the schema and instance level due to dynamically changing situations of a real process (cf. [EKR95, ReDa98, JoHe98]) Note, that in the case of dynamic modifications we also have to define a priori when, i.e. in which context and in which state of execution, certain modifications are allowed in order to ensure the dynamic and semantical consistency of a process. This workflow evolution behavior depends on the ....

....OF target DEFINE: ON finished BY predecessors(During) aborted BY predecessors(During) FOR start OF source DEFINE: SEND TO sucessors(During) Figure 9: Flexible workflow of a change request management process tion and the behavior of the involved tasks. For example, within several approaches [EKR95, HoJa98, ReDa98] the insertion of a new preceding task is allowed only if the task has not been started. However, an active manual task can be suspended, a batch task can be just restarted, transactional tasks can be aborted, or executed tasks can be compensated possibly. The capabilities for behavior definition ....

Ellis, C. A.; Keddara, K.; Rozenberg, G.: "Dynamic Change Within Workflow Systems", in Comstock, N.; Ellis, C. (ed.): Proc. of the Conf. on Organizational Computing Systems COOCS '95. New York (ACM Press) 1995; pp. 10-21.

.... the need for a process model to be modified Moreover, do we need to change the process model even to deal with temporary changes in the software process Is it convenient to change the process model even when a minor deviation from the prescribed process occurs Similarly, in the WFMS domain [14], unforeseen activities and operations (exceptions) that human agents need to accomplish, and that are not specified in the workflow model, are managed by exploiting different kinds of techniques, such as exception handling procedures. 1 In general, the problem of dealing with deviations and ....

....allowed on these descriptions. Using their model, the authors present also a preliminary proposal for a taxonomy of the techniques for consistency handling in programming environments. The problem of dealing with domain level inconsistencies, has also been addressed in the WFMS domain. In [14], Ellis, Keddara and Rozenberg address the problem of dynamic change in workflow systems as the first step to enhance flexibility and usability of WFMS environments. Workflow systems are designed to assist groups of people in carrying out work procedure. They contain knowledge of how procedures ....

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C.A. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In Proceedings of COOCS 95, August 1995.

....captured by one of the exception handlers provided as part of the model. This explains why this situations are called expected exceptions in [7] A different solution adopted by some PSEEs, including SPADE, is to supply mechanisms to support on the fly modification of the process model [15], 16] By using these mechanisms, the project manager may change the process model during enactment, by explicitly modeling the unforeseen situation and the actions needed to cope with it. To support this solution, PSSs may incorporate meta process facilities to describe and support the process ....

C. Ellis, K. Keddara, and G. Rozenberg, "Dynamic change within workflow systems," in Proceedings of COOCS 95, August 1995.

....users in coordinating and scheduling the tasks of a BP. Current process oriented WFMSs are applicable in a reliable and secure manner only if the BP to be supported is well structured and there is no need for ad hoc deviations or dynamic extensions at run time (see Barthelmess and Wainer, 1995; Ellis et al. 1995; Siebert, 1996; Reichert and Dadam, 1997a) As only few BPs are static in this sense, this significantly limits the benefit and the applicability of current workflow (WF) technology. As an example, consider BPs from the clinical domain (see Reichert et al. 1996, 1997b) where it is often not ....

....presented in the following. For the remainder of the paper we concentrate on ad hoc structural changes applied to individual WF instances. We do not explicitly consider changes at the schema level and their propagation to WFs whose execution started with the old schema (see Casati et al. 1996; Ellis et al. 1995). However, many of the presented concepts can be applied to this type of change, too. Section 2 gives an overview of the ADEPT WF model. In section 3 we present a complete and minimal set of change operations which can be used to modify the structure of a WF during its execution. Section 4 ....

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Ellis, C.A., Keddara, K., and Rozenberg, G. (1995). Dynamic Change Within Workflow Systems. Proc. Conf. on Organizational Computing Systems (pp. 10-21). New York, ACM Press.

....mechanisms to change workflow descriptions while they are enacted, mechanisms to test the correctness of changed workflows wrt. to the underlying business process, and mechanisms to deal efficiently with business cases that existed at the time of change (known as the dynamic change problem [7]) Although these problems have been identified (cf. 1, 5, 7, 26] contemporary WFMSs do not provide adequate support for the adaption of workflows. Contemporary WFMSs suffer from two serious shortcomings: First, their modeling components rely on a flat, single schema architecture which ....

....they are enacted, mechanisms to test the correctness of changed workflows wrt. to the underlying business process, and mechanisms to deal efficiently with business cases that existed at the time of change (known as the dynamic change problem [7] Although these problems have been identified (cf. [1, 5, 7, 26]) contemporary WFMSs do not provide adequate support for the adaption of workflows. Contemporary WFMSs suffer from two serious shortcomings: First, their modeling components rely on a flat, single schema architecture which provides no means to explicitly capture the business process a workflow ....

[Article contains additional citation context not shown here]

C.A. Ellis and K. Keddara. Dynamic Change within Workflow Systems. In Proceedings of the 1995 ACM SIGOIS Conference on Organizational Computing Systems (COOCS'95), 1995.

....flexible manufacturing systems, user interaction, and business processes. There are several reasons for using Petri nets for workflow modeling: their formal semantics, graphical nature, expressiveness, analysis techniques and tools provide a framework for modeling and analyzing workflow processes ([3, 5, 6, 12, 13, 27, 31]) The remainder of this paper is organized as follows. First, we motivate the focus of this paper on loosely coupled workflows. Then, we will show how Petri nets can be applied to the domain of interorganizational workflows. For this purpose we introduce some Petri net terminology and some ....

C. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In N. Comstock and C. Ellis, editors, Conf. on Organizational Computing Systems, pages 10 -- 21. ACM SIGOIS, ACM, Aug 1995. Milpitas, CA.

....for modeling and analyzing processes. Petri nets are not based on a software package of a specific vendor and do not cease to exist if a new version is released or when one vendor takes over another vendor. Other references where the use of Petri nets for workflow modeling is advocated are [Aal96b, WR96, MEM94, EKR95, EN93, AH97]. In the remainder of this paper we will show how Petri nets can be applied to the domain of workflow management. To do this, we first introduce the basic concepts of workflow management and workflow management systems. Then we introduce the basic Petri net terminology. In section 4 we show how ....

C. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In N. Comstock and C. Ellis, editors, Conf. on Organizational Computing Systems, pages 10 -- 21. ACM SIGOIS, ACM, Aug 1995. Milpitas, CA.

.... organizational context as represented by other CSCW facilities incorporated in other applications as well as domainspecific information systems such as MIS, OIS, CIM, and CASE systems [15; 17; 42] The challenge is, as Ellis and Keddara aptly put it, to make groupware organizationally aware [16]. With this in mind, the objective of the present paper is to examine the issue of the relationship between cooperative work and the wider organizational context. In doing so, the paper will concentrate on a critique of the Transaction Cost approach, not because of it weaknesses but because of ....

Ellis, Clarence A., and Karim Keddara: "Dynamic change within workflow systems," Unpublished manuscript, 1994.

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C. Ellis, K. Keddara, and G. Rozenberg. Dynamic change within workflow systems. In Proceedings of Conference on Organizational Computing Systems, 1995.

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Ellis, C., Keddara, K. & Rozenberg, G. (1995), Dynamic Change within Workflow Systems, in `Proceedings of the Conference on Organizational Computing Systems (COOCS'95)', ACM Press, Milpitas, USA, pp. 10--21.

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C. Ellis, K. Keddara and G. Rozenberg, "Dynamic change within workflow systems", ACM Conf. on Organizational Computing Systems (COOS 95), August 1995.

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C.A. Ellis, K. Keddara and G. Rozenberg, "Dynamic change within workflow systems", Proc of Conference on Organizational Computing Systems (COOCS'95), Milpitas, CA, August 1995.

No context found.

C. Ellis, K. Keddara, and G. Rozenberg, 1995. Dynamic Changes within Workflow Systems in Proc. of the Conf. on Organizational Computing Systems (COOCS'95)}.

No context found.

Ellis, C., Keddara, K., Rozenberg, G., "Dynamic Change within Workflow Systems," Proceedings of Conference on Organizational Computing Systems (COOCS), Milpitas, CA, 1995, 10-22.

No context found.

Ellis, S., Keddara, K., and Rozenburg, G., "Dynamic Change within Workflow systems," ACM Conference on Organizational Computing Systems (COOSS95), 1995.

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