Results 1  10
of
24
A calculus of mobile processes, I
, 1992
"... We present the acalculus, a calculus of communicating systems in which one can naturally express processes which have changing structure. Not only may the component agents of a system be arbitrarily linked, but a communication between neighbours may carry information which changes that linkage. The ..."
Abstract

Cited by 1184 (31 self)
 Add to MetaCart
We present the acalculus, a calculus of communicating systems in which one can naturally express processes which have changing structure. Not only may the component agents of a system be arbitrarily linked, but a communication between neighbours may carry information which changes that linkage. The calculus is an extension of the process algebra CCS, following work by Engberg and Nielsen, who added mobility to CCS while preserving its algebraic properties. The rrcalculus gains simplicity by removing all distinction between variables and constants; communication links are identified by names, and computation is represented purely as the communication of names across links. After an illustrated description of how the ncalculus generalises conventional process algebras in treating mobility, several examples exploiting mobility are given in some detail. The important examples are the encoding into the ncalculus of higherorder functions (the Icalculus and combinatory algebra), the transmission of processes as values, and the representation of data structures as processes. The paper continues by presenting the algebraic theory of strong bisimilarity and strong equivalence, including a new notion of equivalence indexed by distinctionsi.e., assumptions of inequality among names. These theories are based upon a semantics in terms of a labeled transition system and a notion of strong bisimulation, both of which are expounded in detail in a companion paper. We also report briefly on workinprogress based upon the corresponding notion of weak bisimulation, in which internal actions cannot be observed.
Bigraphs and Mobile Processes (revised)
, 2004
"... A bigraphical reactive system (BRS) involves bigraphs, in which the nesting of nodes represents locality, independently of the edges connecting them; it also allows bigraphs to reconfigure themselves. BRSs aim to provide a uniform way to model spatially distributed systems that both compute and comm ..."
Abstract

Cited by 66 (7 self)
 Add to MetaCart
A bigraphical reactive system (BRS) involves bigraphs, in which the nesting of nodes represents locality, independently of the edges connecting them; it also allows bigraphs to reconfigure themselves. BRSs aim to provide a uniform way to model spatially distributed systems that both compute and communicate. In this memorandum we develop their static and dynamic theory. In Part I we illustrate...
Pure bigraphs: structure and dynamics
, 2005
"... Bigraphs are graphs whose nodes may be nested, representing locality, independently of the edges connecting them. They may be equipped with reaction rules, forming a bigraphical reactive system (Brs) in which bigraphs can reconfigure themselves. Following an earlier paper describing link graphs, a c ..."
Abstract

Cited by 62 (5 self)
 Add to MetaCart
Bigraphs are graphs whose nodes may be nested, representing locality, independently of the edges connecting them. They may be equipped with reaction rules, forming a bigraphical reactive system (Brs) in which bigraphs can reconfigure themselves. Following an earlier paper describing link graphs, a constituent of bigraphs, this paper is a devoted to pure bigraphs, which in turn underlie various more refined forms. Elsewhere it is shown that behavioural analysis for Petri nets, πcalculus and mobile ambients can all be recovered in the uniform framework of bigraphs. The paper first develops the dynamic theory of an abstract structure, a wide reactive system (Wrs), of which a Brs is an instance. In this context, labelled transitions are defined in such a way that the induced bisimilarity is a congruence. This work is then specialised to Brss, whose graphical structure allows many refinements of the theory. The latter part of the paper emphasizes bigraphical theory that is relevant to the treatment of dynamics via labelled transitions. As a running example, the theory is applied to finite pure CCS, whose resulting transition system and bisimilarity are analysed in detail. The paper also mentions briefly the use of bigraphs to model pervasive computing and
Syntax and consistent equation semantics of hybrid Chi
 Journal of Logic and Algebraic Programming
, 2006
"... † This work was partially supported by the EU project HyCon (FP6IST511368) ii The hybrid χ (Chi) formalism integrates concepts from dynamics and control theory with concepts from computer science, in particular from process algebra and hybrid automata. It integrates ease of modeling with a straigh ..."
Abstract

Cited by 60 (24 self)
 Add to MetaCart
(Show Context)
† This work was partially supported by the EU project HyCon (FP6IST511368) ii The hybrid χ (Chi) formalism integrates concepts from dynamics and control theory with concepts from computer science, in particular from process algebra and hybrid automata. It integrates ease of modeling with a straightforward, structured operational semantics. Its ‘consistent equation semantics ’ enforces state changes to be consistent with invariants as in most hybrid automata. Ease of modeling is ensured by means of the following concepts: 1) different classes of variables: discrete and continuous, of subclass jumping or nonjumping, and algebraic; 2) strong time determinism of alternative composition in combination with delayable guards; 3) integration of urgent and nonurgent actions; 4) differential algebraic equations as a process term as in mathematics; 5) steadystate initialization; and 6) several userfriendly modeling extensions. Furthermore, the Chi language incorporates several concepts for complex system specification: 1) process terms for scoping that integrate abstraction, local variables, local channels and recursion definitions; 2) process definition and instantiation that enable process reuse,
Transition systems, link graphs and Petri nets
, 2004
"... A framework is defined within which reactive systems can be studied formally. The framework is based upon scategories, a new variety of categories, within which reactive systems can be set up in such a way that labelled transition systems can be uniformly extracted. These lead in turn to behavi ..."
Abstract

Cited by 29 (5 self)
 Add to MetaCart
A framework is defined within which reactive systems can be studied formally. The framework is based upon scategories, a new variety of categories, within which reactive systems can be set up in such a way that labelled transition systems can be uniformly extracted. These lead in turn to behavioural preorders and equivalences, such as the failures preorder (treated elsewhere) and bisimilarity, which are guaranteed to be congruential. The theory rests upon the notion of relative pushout previously introduced by the authors. The framework
Logics of Dynamical Systems
"... We study the logic of dynamical systems, that is, logics and proof principles for properties of dynamical systems. Dynamical systems are mathematical models describing how the state of a system evolves over time. They are important in modeling and understanding many applications, including embedded ..."
Abstract

Cited by 18 (17 self)
 Add to MetaCart
We study the logic of dynamical systems, that is, logics and proof principles for properties of dynamical systems. Dynamical systems are mathematical models describing how the state of a system evolves over time. They are important in modeling and understanding many applications, including embedded systems and cyberphysical systems. In discrete dynamical systems, the state evolves in discrete steps, one step at a time, as described by a difference equation or discrete state transition relation. In continuous dynamical systems, the state evolves continuously along a function, typically described by a differential equation. Hybrid dynamical systems or hybrid systems combine both discrete and continuous dynamics. Distributed hybrid systems combine distributed systems with hybrid systems, i.e., they are multiagent hybrid systems that interact through remote communication or physical interaction. Stochastic hybrid systems combine stochastic
I.: RCharon, a Modeling Language for Reconfigurable Hybrid Systems
 In: Hybrid Systems: Computation and Control. Volume 3927 of LNCS
, 2006
"... For more information, please contact ..."
(Show Context)
Reniers. Lost in translation: Hybridtime flows vs. realtime transitions
 In Hybrid Systems: Computation and Control
, 2008
"... Abstract. Recently, hybridtime flow systems have been introduced as an extension to timed transition systems, hybrid automata, continuous time evolutions of differential equations etc. Furthermore, a number of notions of bisimulation have been defined on these flow systems reflecting abstraction f ..."
Abstract

Cited by 8 (1 self)
 Add to MetaCart
Abstract. Recently, hybridtime flow systems have been introduced as an extension to timed transition systems, hybrid automata, continuous time evolutions of differential equations etc. Furthermore, a number of notions of bisimulation have been defined on these flow systems reflecting abstraction from certain timing properties. In this paper, we research the difference in abstraction level between this new semantic model of flow systems, and the more traditional model of realtime transition systems. We explore translations between the old and new semantic models, and we give a necessary and sufficient condition, called finiteset refutability, for these translations to be without loss of information. Finally, we show that differential inclusions with an uppersemicontinuous, closed and convex righthand side, are finiteset refutable, and easily extend this result to impuls differential inclusions and hybrid automata.