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Transformations of Petri Nets
"... The aim of this paper is an introduction to the area of Petri net transformations, a rulebased approach for dynamic changes of the net structure of Petri nets. This is especially important for the stepwise construction of Petri nets in the sense of the software development process in software engin ..."
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The aim of this paper is an introduction to the area of Petri net transformations, a rulebased approach for dynamic changes of the net structure of Petri nets. This is especially important for the stepwise construction of Petri nets in the sense of the software development process in software engineering. The concept of Petri net transformations is based on that of graph transformations and highlevel replacement systems and it is introduced within a small case study logistics.
Towards a New Algebraic Approach to Graph Transformation: Basic Concepts, . . .
 TECH. REP. OF THE SCHOOL OF COMP. SCI., UNIV. AUTÓNOMA
, 2006
"... This paper presents a new characterization of graph transformation rules for simple digraphs based on boolean matrix algebra. We introduce the concept of coherence, which allows the analysis of potential incompatibilities among rules that take part in a sequence of productions. Concurrency is studie ..."
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Cited by 6 (5 self)
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This paper presents a new characterization of graph transformation rules for simple digraphs based on boolean matrix algebra. We introduce the concept of coherence, which allows the analysis of potential incompatibilities among rules that take part in a sequence of productions. Concurrency is studied under the interleaving and the explicit parallelism views. For the former, the notion of sequential independence is generalized to arbitrary permutations of rules. For the latter, rule composition is defined, which does not generate intermediate states.
Roles in AgentOriented Modeling
, 2001
"... ... In this paper, we perform such an analysis and identify requirements for a general role concept. We develop such a role concept for a modeling approach based on the UML and graph transformation systems and exemplify its use for the specification (and application) of protocols. Finally, we pro ..."
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Cited by 6 (1 self)
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... In this paper, we perform such an analysis and identify requirements for a general role concept. We develop such a role concept for a modeling approach based on the UML and graph transformation systems and exemplify its use for the specification (and application) of protocols. Finally, we provide a runtime semantics for roles based on concepts from the theory of graph transformation
Concurrent rewriting for graphs with equivalences
 Concurrency Theory
, 2006
"... Abstract. Several applications of graph rewriting systems (notably, some encodings of calculi with name passing) require rules which, besides deleting and generating graph items, are able to coalesce some parts of the graph. This latter feature forbids the development of a satisfactory concurrent se ..."
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Abstract. Several applications of graph rewriting systems (notably, some encodings of calculi with name passing) require rules which, besides deleting and generating graph items, are able to coalesce some parts of the graph. This latter feature forbids the development of a satisfactory concurrent semantics for rewrites (intended as a partial order description of the steps in a computation). This paper proposes the use of graphs with equivalences, i.e., (typed hyper) graphs equipped with an equivalence over nodes, for the analysis of distributed systems. The formalism is amenable to the tools of the doublepushout approach to rewriting, including the theoretical results associated to its concurrent features. The formalism is tested against the encoding of a simple calculus with name mobility, namely the solo calculus.
Towards Graph Transformation with Time
, 2002
"... Following TER nets, an approach to the modelling of time in highlevel Petri nets, we propose a model of time within (attributed) graph transformation systems where time stamps are represented as distinguished node attributes. Corresponding axioms for the time model in TER nets are generalised t ..."
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Following TER nets, an approach to the modelling of time in highlevel Petri nets, we propose a model of time within (attributed) graph transformation systems where time stamps are represented as distinguished node attributes. Corresponding axioms for the time model in TER nets are generalised to graph transformation systems and semantic variations are discussed.
Adhesive dpo parallelism for monic matches
 In Graph Transformation for Verification and Concurrency, GTVC2006
"... This paper presents indispensable technical results of a general theory that will allow to systematically derive from a given reduction system a behavioral congruence that respects concurrency. The theory is developed in the setting of adhesive categories and is based on the work by Ehrig and König ..."
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Cited by 2 (1 self)
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This paper presents indispensable technical results of a general theory that will allow to systematically derive from a given reduction system a behavioral congruence that respects concurrency. The theory is developed in the setting of adhesive categories and is based on the work by Ehrig and König on borrowed contexts; the latter are an instance of relative pushouts, which have been proposed by Leifer and Milner. In order to lift the concurrency theory of dpo rewriting to borrowed contexts we will study the special case of dpo rewriting with monic matches in adhesive categories: more specifically we provide a generalized Butterfly Lemma together with a Local Church Rosser and Parallelism theorem.
Strengthening the Semantics of UML Collaboration Diagrams
, 2000
"... uitable for specifying the semantics of operations and actions. However, the semantic weakness of collaboration diagrams, in particular concerning the collaboration part, limits their expressiveness and prevents their use for precise specifications. In fact, according to the UML specification [12], ..."
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uitable for specifying the semantics of operations and actions. However, the semantic weakness of collaboration diagrams, in particular concerning the collaboration part, limits their expressiveness and prevents their use for precise specifications. In fact, according to the UML specification [12], a collaboration is just the context of an interaction. It does not entail any structural requirements beside the obvious one that objects and links have to be present as soon as they are involved in an interaction. In this note, we sketch how, without changing the syntax, the semantics of collaboration diagrams can be strengthened (and formalized) in order to allow for the specification of pre and postconditions and structural e#ects thus providing a powerful means for action semantics on both the model level and the meta model level. Research partially supported by the ESPRIT Working Group APPLIGRAPH. 2 Collaborations as Graph Transformations A collaboration diagram is based on a col
Autonomous Units and Their Semantics  The Concurrent Case
"... Communities of autonomous units are rulebased and graphtransformational devices to model processes that act and interact, move and communicate, cooperate and compete in a common environment. The autonomous units are independent of each other, and the environment may be large and structured in such ..."
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Communities of autonomous units are rulebased and graphtransformational devices to model processes that act and interact, move and communicate, cooperate and compete in a common environment. The autonomous units are independent of each other, and the environment may be large and structured in such a way that a global synchronization of process activities is not reasonable or not feasible. To reflect this assumption properly, a concurrentprocess semantics of autonomous units is introduced and studied in this paper employing the idea of true concurrency. In particular, causal dependency between actions of autonomous units is compared with shift equivalence known from graph transformation, and concurrent processes in the present approach are related to canonical derivations.
Under consideration for publication in Math. Struct. in Comp. Science Concurrency Can’t Be Observed, Asynchronously †
, 2012
"... The paper is devoted to an analysis of the concurrent features of asynchronous systems. A preliminary step is represented by the introduction of a noninterleaving extension of barbed equivalence. This notion is then exploited in order to prove that concurrency cannot be observed through asynchronou ..."
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The paper is devoted to an analysis of the concurrent features of asynchronous systems. A preliminary step is represented by the introduction of a noninterleaving extension of barbed equivalence. This notion is then exploited in order to prove that concurrency cannot be observed through asynchronous interactions, i.e., that the interleaving and concurrent versions of a suitable asynchronous weak equivalence actually coincide. The theory is validated on some case studies, related to nominal calculi (πcalculus) and visual specification formalisms (Petri nets). Additionally, we prove that a class of systems which are (outputbuffered) asynchronous according to a characterisation previously proposed in the literature falls into our theory.