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20
On Structured Workflow Modelling
"... Recent years have seen the introduction of many commercial workflow management systems. While there are similarities between the languages of various of these systems, there are also significant differences. One particular area of differences is caused by the fact that di erent systems impose differ ..."
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Cited by 48 (13 self)
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Recent years have seen the introduction of many commercial workflow management systems. While there are similarities between the languages of various of these systems, there are also significant differences. One particular area of differences is caused by the fact that di erent systems impose different syntactic restrictions. For example, some work ow management systems do not allow the use of arbitrary loops. In such cases, business analysts have to choose between either conforming to the language in their speci cations or transforming these speci cations afterwards. The latter option is preferable as this allows for a separation of concerns. In this paper we investigate to what extent such transformations are possible in the context of various syntactical restrictions (the most restrictive of which will be referred to as structured workflows). We also provide a deep insight into the consequences, particularly in terms of expressive power, of imposing such restrictions.
Configuration Structures
, 1995
"... this paper we consider a very general model of concurrency, the set systems. These are structures C = (E; C) with E a set and C ` 2 ..."
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Cited by 40 (1 self)
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this paper we consider a very general model of concurrency, the set systems. These are structures C = (E; C) with E a set and C ` 2
Refinement of Actions and Equivalence Notions for Concurrent Systems
 Acta Informatica
, 1998
"... This paper combines and extends the material of [GGa/c/d/e], except for the part in [GGc] on refinement of transitions in Petri nets and the discussion of TCSPlike parallel composition in [GGe]. An informal presentation of some basic ingredients of this paper appeared as [GGb]. Among others, th ..."
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Cited by 36 (1 self)
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This paper combines and extends the material of [GGa/c/d/e], except for the part in [GGc] on refinement of transitions in Petri nets and the discussion of TCSPlike parallel composition in [GGe]. An informal presentation of some basic ingredients of this paper appeared as [GGb]. Among others, the treatment of action refinement in stable and nonstable event structures is new. The research reported here was supported by Esprit project 432 (METEOR), Esprit Basic Research Action 3148 (DEMON), Sonderforschungsbereich 342 of the TU Munchen, ONR grant N0001492J1974 and the Human Capital and Mobility Cooperation Network EXPRESS (Expressiveness of Languages for Concurrency). Contents
History Dependent Automata
, 2001
"... In this paper we present historydependent automata (HDautomata in brief). They are an extension of ordinary automata that overcomes their limitations in dealing with historydependent formalisms. In a historydependent formalism the actions that a system can perform carry information generated i ..."
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Cited by 29 (8 self)
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In this paper we present historydependent automata (HDautomata in brief). They are an extension of ordinary automata that overcomes their limitations in dealing with historydependent formalisms. In a historydependent formalism the actions that a system can perform carry information generated in the past history of the system. The most interesting example is calculus: channel names can be created by some actions and they can then be referenced by successive actions. Other examples are CCS with localities and the historypreserving semantics of Petri nets. Ordinary
M.: Structuring acyclic process models
 Inf. Sys
, 2012
"... Abstract. This paper addresses the problem of transforming a process model with an arbitrary topology into an equivalent wellstructured process model. While this problem has received significant attention, there is still no full characterization of the class of unstructured process models that can ..."
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Cited by 21 (7 self)
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Abstract. This paper addresses the problem of transforming a process model with an arbitrary topology into an equivalent wellstructured process model. While this problem has received significant attention, there is still no full characterization of the class of unstructured process models that can be transformed into wellstructured ones, nor an automated method to structure any process model that belongs to this class. This paper fills this gap in the context of acyclic process models. The paper defines a necessary and sufficient condition for an unstructured process model to have an equivalent structured model under fully concurrent bisimulation, as well as a complete structuring method. 1
On Plain and Hereditary HistoryPreserving Bisimulation
, 1999
"... We investigate the difference between two wellknown notions of independence bisimilarity, historypreserving bisimulation and hereditary historypreserving bisimulation. We characterise the difference between the two bisimulations in tracetheoretical terms, advocating the view that the first i ..."
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Cited by 14 (5 self)
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We investigate the difference between two wellknown notions of independence bisimilarity, historypreserving bisimulation and hereditary historypreserving bisimulation. We characterise the difference between the two bisimulations in tracetheoretical terms, advocating the view that the first is (just) a bisimulation for causality, while the second is a bisimulation for concurrency. We explore the frontier zone between the two notions by defining a hierarchy of bounded backtracking bisimulations.
Non sequential semantics for contextual P/T nets
, 1996
"... . The problem of finding a true concurrent semantics for contextual P/T nets has not been deeply studied yet. The interest for such a semantics has been renewed by some recent proposals to equip mobile process algebras with a net semantics based on this model. In [3] we proposed a causal semantics f ..."
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Cited by 10 (1 self)
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. The problem of finding a true concurrent semantics for contextual P/T nets has not been deeply studied yet. The interest for such a semantics has been renewed by some recent proposals to equip mobile process algebras with a net semantics based on this model. In [3] we proposed a causal semantics for such nets, in this paper we study the non sequential semantics of contextual P/T nets. The semantics is based on a suitable notion of occurrence net and, equipped with a notion of history preserving bisimulation, is more discriminating of the contextual one in general, whereas both are equivalent if we restrict our attention to positive context only. 1 Introduction Place/Transition nets [13] are a well known model used to describe concurrent systems. Recently the interest in contextual nets, i.e. nets that are able to test for presence and absence of tokens, besides the usual flow relation, has grown, mainly due to the use of contextual nets to give a net semantics to the ßcalculus ([8...
Relating Maximalitybased Semantics to Action Refinement in Process Algebras
 Formal Description Techniques VII
, 1994
"... This paper extends to process algebras the notion of maximality which has initially been introduced for prime event structures and P/T nets and shows how this notion of maximality may be used for defining an adequate semantics of Basic LOTOS able to support action refinement. Such an approach appear ..."
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Cited by 8 (4 self)
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This paper extends to process algebras the notion of maximality which has initially been introduced for prime event structures and P/T nets and shows how this notion of maximality may be used for defining an adequate semantics of Basic LOTOS able to support action refinement. Such an approach appears to be more convenient than the classical STsemantics where non atomic actions are split into start and end subactions, as it makes it possible to escape from the potential state space explosion problems induced by action splitting. Main contributions of the paper are related to the definition of a maximalitybased operational semantics of LOTOS and to the expression of maximalitybased bisimulation equivalences which are shown to be preserved under action refinement.
Configuration Structures (Extended Abstract)
 Proceedings 10 th Annual IEEE Symposium on Logic in Computer Science, LICS’95
, 1995
"... Configuration structures provide a model of concurrency generalising the families of configurations of event structures. They can be considered logically, as classes of propositional models; then subclasses can be axiomatised by formulae of simple prescribed forms. Several equivalence relations for ..."
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Cited by 7 (7 self)
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Configuration structures provide a model of concurrency generalising the families of configurations of event structures. They can be considered logically, as classes of propositional models; then subclasses can be axiomatised by formulae of simple prescribed forms. Several equivalence relations for event structures are generalised to configuration structures, and also to general Petri nets. Every configuration structure is shown to be STbisimulation equivalent to a prime event structure with binary conflict; this fails for the tighter history preserving bisimulation. Finally, Petri nets without selfloops under the collective token interpretation are shown behaviourally equivalent to configuration structures, in the sense that there are translations in both directions respecting history preserving bisimulation. This fails for nets with selfloops. 1 Introduction The aim of this paper is to connect several models of concurrency, by providing translations between them and studying whi...
New Bisimulation Semantics for Distributed Systems
, 2007
"... Bisimulation semantics are a very pleasant way to define the semantics of systems, mainly because the simplicity of their definitions and their nice coalgebraic properties. However, they also have some disadvantages: they are based on a sequential operational semantics defined by means of an ordinar ..."
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Cited by 7 (0 self)
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Bisimulation semantics are a very pleasant way to define the semantics of systems, mainly because the simplicity of their definitions and their nice coalgebraic properties. However, they also have some disadvantages: they are based on a sequential operational semantics defined by means of an ordinary transition system, and in order to be bisimilar two systems have to be âtoo similarâ. In this work we will present several natural proposals to define weaker bisimulation semantics that we think properly capture the desired behaviour of distributed systems. The main virtue of all these semantics is that they are real bisimulation semantics, thus inheriting most of the good properties of bisimulation semantics. This is so because they can be defined as particular instances of Jacobs and Hughesâ categorical definition of simulation, which they have already proved to satisfy all those properties.