Workflow management promises a new solution to an age-old problem: controlling, monitoring, optimizing and supporting business processes. What is new about workflow management is the explicit representation of the business process logic which allows for computerized support. This paper discusses the use of Petri nets in the context of workflow management. Petri nets are an established tool for modeling and analyzing processes. On the one hand, Petri nets can be used as a design language for the specification of complex workflows. On the other hand, Petri net theory provides for powerful analysis techniques which can be used to verify the correctness of workflow procedures. This paper introduces workflow management as an application domain for Petri nets, presents state-of-the-art results with respect to the verification of workflows, and highlights some Petri-net-based workflow tools. 1 Introduction In former times, information systems were designed to support the execution of indivi...

. A collection of 10 "rules of thumb" is presented that helps to determine the decidability and complexity of a large number of Petri net problems. 1

. Workflow management systems facilitate the everyday operation of business processes by taking care of the logistic control of work. In contrast to traditional information systems, they attempt to support frequent changes of the workflows at hand. Therefore, the need for analysis methods to verify the correctness of workflows is becoming more prominent. In this chapter we present a method based on Petri nets. This analysis method exploits the structure of the Petri net to find potential errors in the design of the workflow. Moreover, the analysis method allows for the compositional verification of workflows. 1 Introduction Workflow management systems (WFMS) are used for the modeling, analysis, enactment, and coordination of structured business processes by groups of people. Business processes supported by a WFMS are case-driven, i.e., tasks are executed for specific cases. Approving loans, processing insurance claims, billing, processing tax declarations, handling traffic vio...

This paper presents a novel method to derive a Petri net from any specification model that can be mapped into a state-based representation with arcs labeled with symbols from an alphabet of events (a Transition System, TS). The method is based on the theory of regions for Elementary Transition Systems (ETS). Previous work has shown that for any ETS there exists a Petri net with minimum transition count (one transition for each label) with a reachability graph isomorphic to the original Transition System. The method makes use of the following three mechanisms, providing a framework for synthesis of safe Petri nets from arbitrary TSs. Firstly, the requirement of isomorphism is relaxed to a "more behavioural" form of equivalence, bisimulation of TSs, thus extending the class of synthesizable TSs to a new class called Excitation-Closed Transition Systems(ECTS). Secondly, previous work required an oracle (usually the designer) to identify sets of events labeling the TS that were mapped to...

Currently, the Dutch Customs Department is building a nationwide information system to handle all kinds of declarations related to the import and export of goods. For this purpose the Petri-net-based Work ow Management System (WFMS) named COSA has been selected. During the selection process, it turned out that there are several reasons for insisting on a Petri-net-based WFMS. The three main reasons for selecting a Petri-net-based WFMS are discussed in this paper. In our opinion these reasons are also relevant for many other projects involved in the selection or implementation of a WFMS.

We show that safe timed Petri nets can be represented by special automata over the (max,+) semiring, which compute the height of heaps of pieces. This extends to the timed case the classical representation a la Mazurkievicz of the behavior of safe Petri nets by trace monoids and trace languages. For a subclass including all safe Free Choice Petri nets, we obtain reduced heap realizations using structural properties of the net (covering by safe state machine components). We illustrate the heap-based modeling by the typical case of safe jobshops. For a periodic schedule, we obtain a heap-based throughput formula, which is simpler to compute than its traditional timed event graph version, particularly if one is interested in the successive evaluation of a large number of possible schedules. Keywords Timed Petri nets, automata with multiplicities, heaps of pieces, (max,+) semiring, scheduling. I. Introduction The purpose of this paper 1 is to prove the following result: Timed safe Pe...

... This paper presents the verification tool Woflan. Woflan analyzes workflow process definitions downloaded from commercial workflow products using state-of-the-art Petri-net-based analysis techniques. This paper describes the functionality of Woflan emphasizing diagnostics to locate the source of a design error. Woflan is evaluated via two case studies, one involving twenty groups of students designing a complex workflow process and one involving an industrial workflow process designed by Staffware Benelux. The results are encouraging and show that Woflan guides the user in finding and correcting errors in the design of workflows.

Contemporary workflow management systems are ch'iven by explicit process models, i.e., a completely specified workflow design is required in order to enact a given workflow process. Creating a workflow design is a complicated time-consuming process and typically there are discrepancies between the actual workflow processes and the processes as perceived by the management. Therefore, we have developed techniques for discovering workflow models. Starting point for such techniques are so-called "workflow logs" containing information about the workflow process as it is actually being executed. In this paper, we extend our existing mining technique c [4] to incorporate time. We assume that events in workflow logs bear timestamps. This information is used to attribute timing such as queue times to the discovered workflow model. The approach is based on Petri nets and timing information is attached to places. This paper also presents our workflow-mining tool EMIT. This tool translates the workflow log of several commercial systems (e.g., Staffware) to an independent XML format. Based on this format the tool mines for causal relations and produces a graphical workflow model expressed in terms of Petri nets.

Today's corporations often must operate across organizational boundaries. Phenomena such as electronic commerce, extended enterprises, and the Internet stimulate cooperation between organizations. Therefore, it is interesting to consider workflows distributed over a number of organizations. Interorganizational workflow offers companies the opportunity to re-shape business processes beyond the boundaries of their own organizations. Two important questions are addressed in this paper: (1) What are the minimal requirements any interorganizational workflow should satisfy?, and (2) How does one decide whether an interorganizational workflow, modeled in terms of Petri nets, is consistent with an interaction structure specified through a message sequence chart?

Enterprise information systems support and control operational business processes ranging from simple internal back-office processes to complex interorganizational processes. Technologies such as Workflow Management (WFM), Enterprise Application Integration (EAI), Enterprise Resource Planning (ERP), and Web Services (WS) typically focus on the realization of IT support rather than monitoring the operational business processes. Process mining aims at extracting information from event logs to capture the business process as it is being executed. In this paper, we try to put the topic of process mining into context, discuss the main issues around process mining, and finally we introduce the papers in this special issue.