Process architecture

About: Process architecture is a research topic. Over the lifetime, 4876 publications have been published within this topic receiving 104171 citations.

Towards a complete design method for embedded systems using predicate/transition-nets

Abstract: In this paper, we present a new approach to embedded system design based on modeling discrete and also continuous system parts with high level Petri—Nets. Our investigations concentrate on a complete design flow, analysis on high level Petri—Nets and their meaning for hardware/software partitioning of real-time embedded systems. The concepts for hybrid modeling of discrete and continuous systems are applied in an example in the domain of mechatronic systems.

Stepwise construction and refinement of dependability models

Abstract: This paper presents a stepwise approach for dependability modeling, based on Generalized Stochastic Petri Nets (GSPNs). The first-step model called functional-level model, can be built as early as system functional specifications and then completed by the structural model as soon as the system architecture is known, even at a very high level. The latter can be refitted according to three different aspects: component decomposition, state and event fine-tuning and distribution adjustment to take into account increasing event rates. We define specific rules to make the successive transformations as easy and systematic as possible. This approach allows the various dependencies to be taken into account at the right level of abstraction: functional dependency, structural dependency and those induced by non-exponential distributions. A part of the approach is applied to an instrumentation and control system (I&C) in power plants.

Structure Theory of Petri Nets

Abstract: The aim of this tutorial is to give a concise, but nonetheless not too narrow, overview of definitions and results pertaining centrally to Petri net structure theory. The Petri net model considered in these notes are the classical place/transition nets, as they have been defined in the First Advanced Course held in 1979 and originate back to the late Sixties. Structure theory asks what behavioural properties of a Petri net can be derived from its structural properties. Other aspects of Petri nets are neglected to a large extent in the present notes, such as various extensions and generalisations of central notions and results, as well as almost all algorithmic and complexity-theoretic consequences that accompany the structure-theoretic results. Because full proofs can easily be retrieved from the literature, they are not given, unless they are small and perhaps somewhat characteristic for Petri net oriented reasoning. Proof ideas are often sketched, however, and the sharpness of various results is accentuated by means of examples and counterexamples. A list for further reading is also provided.

Petri net reachability checking is polynomial with optimal abstraction hierarchies

Abstract: The Petri net model is a powerful state transition oriented model to analyse, model and evaluate asynchronous and concurrent systems. However, like other state transition models, it encounters the state explosion problem. The size of the state space increases exponentially with the system complexity. This paper is concerned with a method of abstracting automatically Petri nets to simpler representations, which are ordered with respect to their size. Thus it becomes possible to check Petri net reachability incrementally. With incremental approach we can overcome the exponential nature of Petri net reachability checking. We show that by using the incremental approach, the upper computational complexity bound for Petri net reachability checking with optimal abstraction hierarchies is polynomial. The method we propose considers structural properties of a Petri net as well an initial and a final marking. In addition to Petri net abstraction irrelevant transitions for a given reachability problem are determined. By removing these transitions from a net, impact of the state explosion problem is reduced even more.

Decomposition of the supervisory control problem for Petri nets under preservation of maximal permissiveness

Abstract: Decomposing the design of supervisory control laws for Petri nets is an efficient way to tackle its complexity. We consider legal sets which are the union of two sets. In general, this can make the control law obtained via decomposition too restrictive, i.e., it disables more transitions than necessary. Generalizing existing results, we give structural conditions under which the control law via decomposition is maximally permissive.