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LifeCycle Inheritance  A PetriNetBased Approach
 Application and Theory of Petri Nets 1997, volume 1248 of Lecture Notes in Computer Science
, 1997
"... . Inheritance is one of the key issues of objectorientation. The inheritance mechanism allows for the definition of a subclass which inherits the features of a specific superclass. This means that methods and attributes defined for the superclass, are also available for objects of the subclass. ..."
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Cited by 43 (15 self)
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. Inheritance is one of the key issues of objectorientation. The inheritance mechanism allows for the definition of a subclass which inherits the features of a specific superclass. This means that methods and attributes defined for the superclass, are also available for objects of the subclass. Existing methods for objectoriented modeling and design, abstract from the dynamic behavior of objects when defining inheritance. Nevertheless, it would be useful to have a mechanism which allows for the inheritance of dynamic behavior. This paper describes a Petrinet based approach to the formal specification and verification of this type of inheritance. We use Petri nets to specify the dynamics of an object class. The Petrinet formalism allows for a graphical representation of the life cycle of objects which belong to a specific object class. Four possible inheritance relations are defined. These inheritance relations can be verified automatically. Moreover, four powerful transfo...
Discrete Time Process Algebra with Silent Step
, 2000
"... The axiom system ACP of [10] was extended to discrete time in [6]. Here, we proceed to define the silent step in this theory in branching bisimulation semantics [7, 15] rather than weak bisimulation semantics [11, 20]. The version using relative timing is discussed extensively, versions using absolu ..."
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Cited by 16 (7 self)
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The axiom system ACP of [10] was extended to discrete time in [6]. Here, we proceed to define the silent step in this theory in branching bisimulation semantics [7, 15] rather than weak bisimulation semantics [11, 20]. The version using relative timing is discussed extensively, versions using absolute and parametric timing are presented in brief. A term model and a graph model are presented and soundness and completeness results are given. The time free theories BPA # and BPA # # are embedded in the discrete time theories. Examples of the use of the relative time theory are given by means of some calculations on communicating buffers. Note: Partial support received from ESPRIT Basic Research Action 7166, CONCUR2. This paper supersedes [4]. 1 Introduction Process algebra was introduced by Milner in the form of CCS [19]. The original design of CCS and of subsequent versions of process algebra such as ACP [10] and TCSP [14] involves no explicit notion of time. Time is present in the int...
Rooted branching bisimulation as a congruence
 Journal of Computer and System Sciences
, 2000
"... This article presents a congruence format, in structural operational semantics, for rooted branching bisimulation equivalence. The format imposes additional requirements on Groote’s ntyft format. It extends an earlier format by Bloom with standard notions such as recursion, iteration, predicates, an ..."
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Cited by 15 (6 self)
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This article presents a congruence format, in structural operational semantics, for rooted branching bisimulation equivalence. The format imposes additional requirements on Groote’s ntyft format. It extends an earlier format by Bloom with standard notions such as recursion, iteration, predicates, and negative premises. 1
Inheritance of Behavior
 Journal of Logic and Algebraic Programming
, 1999
"... One of the key issues of objectoriented modeling and design is inheritance. It allows for the definition of subclasses that inherit features of some superclass. Inheritance is well defined for static properties of classes such as attributes and methods. However, there is no general agreement on the ..."
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Cited by 12 (1 self)
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One of the key issues of objectoriented modeling and design is inheritance. It allows for the definition of subclasses that inherit features of some superclass. Inheritance is well defined for static properties of classes such as attributes and methods. However, there is no general agreement on the meaning of inheritance when considering the dynamic behavior of objects, captured by their life cycles. This paper studies inheritance of behavior both in a simple processalgebraic setting and in a Petrinet framework. Process algebra is chosen, because it concentrates on behavior, while abstracting from the internal states of processes. The result of the algebraic study is a clear conceptual understanding of inheritance of behavior. It can be expressed in terms of blocking and hiding method calls. The results in the algebraic framework inspire the development of the concept of inheritance of behavior in the Petrinet framework. The Petrinet formalism allows for a graphical representation...
A compositional theory of refinement for branching time
 12th IFIP WG 10.5 Advanced Research Working Conference, CHARME 2003, volume 2860 of LNCS
, 2003
"... Abstract. I develop a compositional theory of refinement for the branching time framework based on stuttering simulation and prove that if one system refines another, then a refinement map always exists. The existence of refinement maps in the linear time framework was studied in an influential pape ..."
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Cited by 10 (6 self)
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Abstract. I develop a compositional theory of refinement for the branching time framework based on stuttering simulation and prove that if one system refines another, then a refinement map always exists. The existence of refinement maps in the linear time framework was studied in an influential paper by Abadi and Lamport. My interest in proving analogous results for the branching time framework arises from the observation that in the context of mechanical verification, branching time has some important advantages. By setting up the refinement problem in a way that differs from the Abadi and Lamport approach, I obtain a proof of the existence of refinement maps (in the branching time framework) that does not depend on any of the conditions found in the work of Abadi and Lamport e.g., machine closure, finite invisible nondeterminism, internal continuity, the use of history and prophecy variables, etc. A direct consequence is that refinement maps always exist in the linear time framework, subject only to the use of prophecylike variables. 1
When are two workflows the same
 of Australian Computer Society
, 2005
"... In the area of workflow management, one is confronted with a large number of competing languages and the relations between them (e.g. relative expressiveness) are usually not clear. Moreover, even within the same language it is generally possible to express the same workflow in different ways, a fea ..."
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Cited by 9 (1 self)
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In the area of workflow management, one is confronted with a large number of competing languages and the relations between them (e.g. relative expressiveness) are usually not clear. Moreover, even within the same language it is generally possible to express the same workflow in different ways, a feature known as variability. This paper aims at providing some of the formal groundwork for studying relative expressiveness and variability by defining notions of equivalence capturing different views on how workflow systems operate. Firstly, a notion of observational equivalence in the absence of silent steps is defined and related to classical bisimulation. Secondly, a number of equivalence notions in the presence of silent steps are defined. A distinction is made between the case where silent steps are visible (but not controllable) by the environment and the case where silent steps are not visible, i.e., there is an alternation between system events and environment interactions. It is shown that these notions of equivalence are different and do not coincide with classical notions of bisimulation with silent steps (e.g. weak and branching). 1
Cones and Foci for Protocol Verification Revisited
 In Proc. 6th Conference on Foundations of Software Science and Computation Structures, LNCS 2620
, 2003
"... Abstract. We define a cones and foci proof method, which rephrases the question whether two system specifications are branching bisimilar in terms of proof obligations on relations between data objects. Compared to the original cones and foci method from Groote and Springintveld [22], our method is ..."
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Cited by 9 (4 self)
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Abstract. We define a cones and foci proof method, which rephrases the question whether two system specifications are branching bisimilar in terms of proof obligations on relations between data objects. Compared to the original cones and foci method from Groote and Springintveld [22], our method is more generally applicable, and does not require a preprocessing step to eliminate τloops. We prove soundness of our approach and give an application. 1
Equivalence checking for infinite systems using parameterized boolean equation systems
 In Proc. CONCUR’07, LNCS 4703
, 2007
"... Abstract. In this paper, we provide a transformation from the branching bisimulation problem for infinite, concurrent, dataintensive systems in linear process format, into solving Parameterized Boolean Equation Systems. We prove correctness and illustrate the approach with two examples. We also pro ..."
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Cited by 6 (3 self)
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Abstract. In this paper, we provide a transformation from the branching bisimulation problem for infinite, concurrent, dataintensive systems in linear process format, into solving Parameterized Boolean Equation Systems. We prove correctness and illustrate the approach with two examples. We also provide small adaptations to obtain similar transformations for strong and weak bisimulations and simulation equivalences. 1
Completeness in DiscreteTime Process Algebra
, 1995
"... We prove soundness and completeness for some ACPstyle concrete, relativetime, discretetime process algebras. We treat nondelayable actions, delayable actions, and immediate deadlock. Basic process algebras are examined extensively, and also some concurrent process algebras are considered. We con ..."
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Cited by 5 (3 self)
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We prove soundness and completeness for some ACPstyle concrete, relativetime, discretetime process algebras. We treat nondelayable actions, delayable actions, and immediate deadlock. Basic process algebras are examined extensively, and also some concurrent process algebras are considered. We conclude with ACP drt , which combines all described features in one theory. 1991 Mathematics Subject Classification: 68Q10, 68Q22, 68Q55. 1991 CR Categories: D.1.3, D.3.1, F.1.2, F.3.2. Keywords: ACP, process algebra, discrete time, relative time, elimination, soundness, completeness, BPA, BPA # , BPA  drt #, BPA  drt ID, BPA drt ID, BPA  drt , BPA drt , PA  drt ID, ACP  drt ID, PA drt , ACP drt , RSP(USD). Note: The investigations of the first author were supported by Philips Research Laboratories Eindhoven, The Netherlands. The investigations of the second author were supported by the Netherlands Computer Science Research Foundation (SION) with financial support from the N...