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110
Bigraphs and Mobile Processes
, 2003
"... 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 ..."
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Cited by 1064 (29 self)
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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...
Mobile ambients
 In Proceedings of POPL'98
, 1998
"... Laboratory We introduce a calculus describing the movement of processes and devices, including movement through administrative domains. ..."
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Cited by 849 (29 self)
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Laboratory We introduce a calculus describing the movement of processes and devices, including movement through administrative domains.
Abstractions for mobile computation
, 1999
"... Abstract. We discuss the difficulties caused by mobile computing and mobile computation over wide area networks. We propose a unified framework for overcoming such difficulties. 1 ..."
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Cited by 126 (3 self)
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Abstract. We discuss the difficulties caused by mobile computing and mobile computation over wide area networks. We propose a unified framework for overcoming such difficulties. 1
The πCalculus in Direct Style
, 1997
"... We introduce a calculus which is a direct extension of both the and the π calculi. We give a simple type system for it, that encompasses both Curry's type inference for the calculus, and Milner's sorting for the πcalculus as particular cases of typing. We observe that the various contin ..."
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Cited by 66 (2 self)
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We introduce a calculus which is a direct extension of both the and the π calculi. We give a simple type system for it, that encompasses both Curry's type inference for the calculus, and Milner's sorting for the πcalculus as particular cases of typing. We observe that the various continuation passing style transformations for terms, written in our calculus, actually correspond to encodings already given by Milner and others for evaluation strategies of terms into the πcalculus. Furthermore, the associated sortings correspond to wellknown double negation translations on types. Finally we provide an adequate cps transform from our calculus to the πcalculus. This shows that the latter may be regarded as an "assembly language", while our calculus seems to provide a better programming notation for higherorder concurrency.
Global/local subtyping and capability inference for a distributed πcalculus
 In Proceedings of ICALP '98, LNCS 1443
, 1998
"... This paper considers how locality restrictions on the use of capabilities can be enforced by a static type system. A distributed πcalculus with a simple reduction semantics is introduced, integrating location and migration primitives from the Distributed Join Calculus with asynchronous π communicat ..."
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Cited by 66 (11 self)
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This paper considers how locality restrictions on the use of capabilities can be enforced by a static type system. A distributed πcalculus with a simple reduction semantics is introduced, integrating location and migration primitives from the Distributed Join Calculus with asynchronous π communication. It is given a type system in which the input and output capabilities of channels may be either global, local or absent. This allows compiletime optimization where possible but retains the expressiveness of channel communication. Subtyping allows all communications to be invoked uniformly. We show that the most local possible capabilities for internal channels can be inferred automatically.
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 ..."
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Cited by 62 (6 self)
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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...
Observational Determinism for Concurrent Program Security
 In Proc. 16th IEEE Computer Security Foundations Workshop
, 2003
"... Noninterference is a property of sequential programs that is useful for expressing security policies for data confidentiality and integrity. However, extending noninterference to concurrent programs has proved problematic. In this paper we present a relatively expressive secure concurrent language. ..."
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Cited by 54 (9 self)
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Noninterference is a property of sequential programs that is useful for expressing security policies for data confidentiality and integrity. However, extending noninterference to concurrent programs has proved problematic. In this paper we present a relatively expressive secure concurrent language. This language, based on existing concurrent calculi, provides firstclass channels, higherorder functions, and an unbounded number of threads. Welltyped programs obey a generalization of noninterference that ensures immunity to internal timing attacks and to attacks that exploit information about the thread scheduler. Elimination of these refinement attacks is possible because the enforced security property extends noninterference with observational determinism. Although the security property is strong, it also avoids some of the restrictiveness imposed on previous securitytyped concurrent languages.
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 ..."
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Cited by 51 (5 self)
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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
Asynchronous and Deterministic Objects
 IN 31ST ACM SYMPOSIUM ON PRINCIPLES OF PROGRAMMING LANGUAGES
, 2004
"... This paper aims at providing confluence and determinism properties in concurrent processes, more specifically within the paradigm of objectoriented systems. Such results should allow one to program parallel and distributed applications that behave in a deterministic manner, even if they are distrib ..."
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Cited by 41 (17 self)
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This paper aims at providing confluence and determinism properties in concurrent processes, more specifically within the paradigm of objectoriented systems. Such results should allow one to program parallel and distributed applications that behave in a deterministic manner, even if they are distributed over local or wide area networks. For that purpose, an object calculus is proposed. Its key characteristics are asynchronous communications with futures, and sequential execution within each process. While
On the expressiveness of internal mobility in namepassing calculi
, 1998
"... We consider the language rI, a namepassing calculus introduced by Sangiorgi, where only private names can be exchanged among processes (internal mobility). The calculus 7cI has simple mathematical theory, very close to that of CCS. We provide an encoding from (an asynchronous variant of) the ~rca ..."
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Cited by 39 (0 self)
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We consider the language rI, a namepassing calculus introduced by Sangiorgi, where only private names can be exchanged among processes (internal mobility). The calculus 7cI has simple mathematical theory, very close to that of CCS. We provide an encoding from (an asynchronous variant of) the ~rcalculus to IrI, which is fully abstract on the reduction relations of the two calculi. The result shows that, in namepassing calculi, internal mobility is the essential ingredient as far as expressiveness i concerned. 1 In t roduct ion By now, the 7rcalculus [13] is generally recognized as the prototypical algebraic language for describing concurrent systems with dynamically evolving communication linkage. The latter phenomenon, known as mobility, is modelled through the passing of channel names among processes (namepassing). The expressive power of the ~rcalculus is demonstrated by the existence of simple and fully abstract ranslations into it for a variety of computational formalisms, including Acalculus [12], higherorder process calculi [15] and calculi which permits reasoning on the causal or spatial structure of the systems [4, 17]. The price to pay for this expressiveness i a rather complex mathematical theory of the rcalculus. A source of complications i, above all, the need to take name instantiation (otherwise called substitution) into account. Input and output at a of a tuple of names b are written, respectively, asa(b).P (input prefix) and ~(b).P (output prefix), with P representing the continuation of the prefix. An input and an output prefix can be consumed in a communication, where a tuple of names is passed and used to instantiate the formal parameters of the input prefix, thus: a(c).P]5<b>.Q ~, P{b/~}]Q (,) with {b~} denoting the instantiation ofnames in ~'with names in b. Name instantiation is a central aspect in the mathematical treatment of certain behavioural relations.