Jörn Freiheit

Modelling of Cross-Organizational Business Processes - Current Methods and Standards

Not only since the upcoming of Service-oriented Architectures the modelling of cross-organizational business processes is a heavily investigated field comprising dozens of standards based on different concepts. New techniques on the implementation site, e.g. Web Service orchestration and choreography, further extended the possibilities and requirements on such standards. To systematically order and present a comprehensive state of the art of relevant methods and standards this paper first describes requirements that occur in cross-organizational business processes both for concepts and modelling languages. Then the most important state of the art concepts for modelling cross-organizational processes are described. Based on the requirements defined before and the presented concepts, selected modelling languages are analysed.

Approximate closed-form aggregation of a fork-join structure in generalised stochastic petri nets

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 analysis. This paper details the derivation of computationally-simple closed-form expressions which permit the aggregation of a GSPN subnet featuring a fork-join structure. The aggregation expressions presented in this paper do not require the generation of the underlying continuous time Markov chain of the original net, and do not follow an iterative procedure. The resulting aggregated GSPN accurately approximates the stationary token distribution behaviour of the original net, and this is shown by the analysis of a number of example GSPNs.

Enhanced workflow models as a tool for judicial practitioners

In the past, attempts were made to make law and justice more accessible to general audience and to legal practitioners using models of legal texts. We present a new approach to make the judicial workflows easier to understand. By using process modelling methods, the developed representation emphasises on improving transparency, on promoting mutual trust and on formalising models for verification. To design semi-formal models interviews are used as well as legal texts are consulted. These models are formalised in a second step. The models are enhanced with hierarchies, modules and the generation of different views. Language problems are also treated. The subsequent formalised models are used to verify trigger events and timing of judicial workflows, which have very specific requirements in terms of periods of time and fixed dates. A new tool, Lexecute, is presented which gives new perspectives into justice and reveal new potentials for modelling methods in the field of justice.