Jörn Freiheit

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One of the main features of Event driven Process Chains (EPCs) is the non-local semantics of the OR-join and the XOR-join connectors. Simulating this non-local semantics faithfully and efficiently is still a challenging problem. A year ago, we have shown that the semantics of moderately sized EPCs can be calculated in reasonable time by using techniques(More)
The design of real-time systems requires modeling and analysis techniques, to ensure their correct and timely operation. In many cases a realistic model should be able to cover both fixed and stochastic times. Stochastic Petri nets are a promising description technique in this field, but mixing deterministic and randomly distributed times in one model makes(More)
Petri nets are useful for modelling complex concurrent systems. While modelling using Petri nets focusses on local states and actions , the analysis methods are concerned with global states and their transitions. Unfortunately generation of the complete state space suffers from the well-known state space explosion problem. This paper presents a method to(More)
In this paper an aggregation technique for generalised stochastic Petri nets (GSPNs) possessing synchronised parallel structures is presented. Parallel processes featuring synchronisation constraints commonly occur in fields such as product assembly and computer process communications, however their existence in closed networks severely complicates(More)
In this paper we bridge the gap between performance evaluation and the modelling of business processes. On the basis of a case study from the field of operational planning processes we investigate the performance evaluation of human resource management processes. In particular we consider the affect of timing in operational planning processes. We use(More)
The paper discusses the usability concept of workflow services for event-driven process chains. Usability is similar to controllability, known from Workflow net based BPEL semantics theory. Based on the observation, that if business processes interact (for instance because one of them is a service), it must be possible to check whether this is structurally(More)