Results 1  10
of
120
A Foundation for Actor Computation
 Journal of Functional Programming
, 1998
"... We present an actor language which is an extension of a simple functional language, and provide a precise operational semantics for this extension. Actor configurations represent open distributed systems, by which we mean that the specification of an actor system explicitly takes into account the in ..."
Abstract

Cited by 235 (51 self)
 Add to MetaCart
We present an actor language which is an extension of a simple functional language, and provide a precise operational semantics for this extension. Actor configurations represent open distributed systems, by which we mean that the specification of an actor system explicitly takes into account the interface with external components. We study the composability of such systems. We define and study various notions of testing equivalence on actor expressions and configurations. The model we develop provides fairness. An important result is that the three forms of equivalence, namely, convex, must, and may equivalences, collapse to two in the presence of fairness. We further develop methods for proving laws of equivalence and provide example proofs to illustrate our methodology.
The πcalculus as a theory in linear logic: Preliminary results
 3rd Workshop on Extensions to Logic Programming, LNCS 660
, 1993
"... The agent expressions of the πcalculus can be translated into a theory of linear logic in such a way that the reflective and transitive closure of πcalculus (unlabeled) reduction is identified with “entailedby”. Under this translation, parallel composition is mapped to the multiplicative disjunct ..."
Abstract

Cited by 102 (17 self)
 Add to MetaCart
The agent expressions of the πcalculus can be translated into a theory of linear logic in such a way that the reflective and transitive closure of πcalculus (unlabeled) reduction is identified with “entailedby”. Under this translation, parallel composition is mapped to the multiplicative disjunct (“par”) and restriction is mapped to universal quantification. Prefixing, nondeterministic choice (+), replication (!), and the match guard are all represented using nonlogical constants, which are specified using a simple form of axiom, called here a process clause. These process clauses resemble Horn clauses except that they may have multiple conclusions; that is, their heads may be the par of atomic formulas. Such multiple conclusion clauses are used to axiomatize communications among agents. Given this translation, it is nature to ask to what extent proof theory can be used to understand the metatheory of the πcalculus. We present some preliminary results along this line for π0, the “propositional ” fragment of the πcalculus, which lacks restriction and value passing (π0 is a subset of CCS). Using ideas from prooftheory, we introduce coagents and show that they can specify some testing equivalences for π0. If negationasfailuretoprove is permitted as a coagent combinator, then testing equivalence based on coagents yields observational equivalence for π0. This latter result follows from observing that coagents directly represent formulas in the HennessyMilner modal logic. 1
Foundations of Timed Concurrent Constraint Programming
 Proceedings of the Ninth Annual IEEE Symposium on Logic in Computer Science
, 1994
"... We develop a model for timed, reactive computation by extending the asynchronous, untimed concurrent constraint programming model in a simple and uniform way. In the spirit of process algebras, we develop some combinators expressible in this model, and reconcile their operational, logical and denota ..."
Abstract

Cited by 90 (10 self)
 Add to MetaCart
We develop a model for timed, reactive computation by extending the asynchronous, untimed concurrent constraint programming model in a simple and uniform way. In the spirit of process algebras, we develop some combinators expressible in this model, and reconcile their operational, logical and denotational character. We show how programs may be compiled into finitestate machines with loopfree computations at each state, thus guaranteeing bounded response time. 1 Introduction and Motivation Reactive systems [12,3,9] are those that react continuously with their environment at a rate controlled by the environment. Execution in a reactive system proceeds in bursts of activity. In each phase, the environment stimulates the system with an input, obtains a response in bounded time, and may then be inactive (with respect to the system) for an arbitrary period of time before initiating the next burst. Examples of reactive systems are controllers and signalprocessing systems. The primary issu...
Testing equivalence for mobile processes
 Proceedings of CONCUR ’92, LNCS 630
, 1995
"... Abst rac t. The impact of applying the testing approach to a calculus of processes with a dynamically changing structure is investigated. A proof system for the finite fragment of the calculus is introduced which consists of two groups of laws: those for strong observational equivalence and those ne ..."
Abstract

Cited by 66 (10 self)
 Add to MetaCart
Abst rac t. The impact of applying the testing approach to a calculus of processes with a dynamically changing structure is investigated. A proof system for the finite fragment of the calculus is introduced which consists of two groups of laws: those for strong observational equivalence and those needed to deal with x actions. Soundness and completeness w.r.t, a testing preorder are shown. A fully abstract denotational model for the language is presented which relies on the existence of normal forms for processes. 1.
A Secure Active Network Environment Architecture  Realization in SwitchWare
 IEEE NETWORK
"... Active Networks is a network infrastructure which is programmable on a peruser or even perpacket basis. Increasing the flexibility of such network infrastructures invites new security risks. Coping with these security risks represents the most fundamental contribution of Active Network research. T ..."
Abstract

Cited by 61 (22 self)
 Add to MetaCart
Active Networks is a network infrastructure which is programmable on a peruser or even perpacket basis. Increasing the flexibility of such network infrastructures invites new security risks. Coping with these security risks represents the most fundamental contribution of Active Network research. The security concerns can be divided into those which affect the network as a whole and those which affect individual elements. It is clear that the element problems must be solved first, as the integrity of networklevel solutions will be based on trust of the network elements. In this
A Calculus of Communicating Systems with Label Passing
, 1986
"... This report is essential Uffe Engbergs thesis for the MSc degree from Department of Computer Science, Aarhus University except that all proofs of theorems have been left out. Should anyone have interest in particular proofs, they may be obtained by contacting one of the authors. 1 Introduction ..."
Abstract

Cited by 58 (0 self)
 Add to MetaCart
This report is essential Uffe Engbergs thesis for the MSc degree from Department of Computer Science, Aarhus University except that all proofs of theorems have been left out. Should anyone have interest in particular proofs, they may be obtained by contacting one of the authors. 1 Introduction
The Lazy Lambda Calculus in a Concurrency Scenario (Extended Abstract)
 Information and Computation
, 1994
"... ) Davide Sangiorgi LFCS  Department of Computer Science Edinburgh University Edinburgh  EH9 3JZ  UK Abstract The use of lambda calculus in richer settings, possibly involving parallelism, is examined in terms of its effect on the equivalence between lambda terms. We concentrate here on Abra ..."
Abstract

Cited by 58 (8 self)
 Add to MetaCart
) Davide Sangiorgi LFCS  Department of Computer Science Edinburgh University Edinburgh  EH9 3JZ  UK Abstract The use of lambda calculus in richer settings, possibly involving parallelism, is examined in terms of its effect on the equivalence between lambda terms. We concentrate here on Abramsky's lazy lambda calculus and we follow two directions. First, the lambda calculus is studied within a process calculus by examining the equivalence $ induced by Milner's encoding into the calculus. We give exact operational and denotational characterizations for $. Secondly, we examine Abramsky's applicative bisimulation when the lambda calculus is augmented with (wellformed) operators, i.e. symbols equipped with reduction rules describing their behaviour. Then, maximal discrimination is obtained when all operators are considered; we show that this discrimination coincides with the one given by $ and that the adoption of certain nondeterministic operators is sufficient and necessary...
Communicating mobile processes: introducing occampi
 In 25 Years of CSP
, 2005
"... Abstract. This paper introduces occamπ, an efficient and safe binding of key elements from Hoare’s CSP and Milner’s πcalculus into a programming language of industrial strength. A brief overview of classical occam is presented, before focussing on the extensions providing data, channel and process ..."
Abstract

Cited by 57 (18 self)
 Add to MetaCart
Abstract. This paper introduces occamπ, an efficient and safe binding of key elements from Hoare’s CSP and Milner’s πcalculus into a programming language of industrial strength. A brief overview of classical occam is presented, before focussing on the extensions providing data, channel and process mobility. Some implementation details are given, along with current benchmark results. Application techniques exploiting mobile processes for the direct modelling of largescale natural systems are outlined, including the modelling of locality (so that freeranging processes can locate each other). Runtime overheads are sufficiently low so that systems comprising millions of dynamically assembling and communicating processes are practical on modest processor resources. The ideas and technology will scale further to address larger systems of arbitrary complexity, distributed over multiple processors with no semantic discontinuity. Semantic design, comprehension and analysis are made possible through a natural structuring of systems into multiple levels of network and the compositionality of the underlying algebra. 1
Asynchronous Communication Model Based on Linear Logic
 Formal Aspects of Computing
, 1995
"... We propose a new framework called ACL for concurrent computation based on linear logic. ACL is a kind of linear logic programming framework, where its operational semantics is described in terms of proof construction in linear logic. We also give a modeltheoretic semantics as a natural extension of ..."
Abstract

Cited by 48 (6 self)
 Add to MetaCart
We propose a new framework called ACL for concurrent computation based on linear logic. ACL is a kind of linear logic programming framework, where its operational semantics is described in terms of proof construction in linear logic. We also give a modeltheoretic semantics as a natural extension of phase semantics, a model of linear logic. Our framework well captures concurrent computation based on asynchronous communication. It will, therefore, provide us with a new insight into other models of concurrent computation from a logical point of view. We also expect ACL to become a formal framework for verification, reasoning, and transformation of concurrent programs by the use of techniques for traditional logic programming. ACL's attractive features for concurrent programming paradigms are also discussed. 1 Introduction For future massively parallel processing environments, concurrent programming languages based on asynchronous communication would become more and more important. Due ...
A lightweight coordination middleware for mobile computing
 In Proceedings of the 6th international conference on coordination models and languages
, 2004
"... Abstract. This paper presents Limone, a new coordination model that facilitates rapid application development over ad hoc networks consisting of logically mobile agents and physically mobile hosts. Limone assumes an agentcentric perspective on coordination by allowing each agent to define its own a ..."
Abstract

Cited by 41 (17 self)
 Add to MetaCart
Abstract. This paper presents Limone, a new coordination model that facilitates rapid application development over ad hoc networks consisting of logically mobile agents and physically mobile hosts. Limone assumes an agentcentric perspective on coordination by allowing each agent to define its own acquaintance policy and by limiting all agentinitiated interactions to agents that satisfy the policy. Agents that satisfy this acquaintance policy are stored in an acquaintance list, which is automatically maintained by the system. This asymmetric style of coordination allows each agent to focus only on relevant peers. Coordination activities are restricted solely to tuple spaces owned by agents in the acquaintance list. Limone tailors Lindalike primitives for mobile environments by eliminating remote blocking and complex group operations. It also provides timeouts for all distributed operations and reactions, which enable asynchronous communication with agents in the acquaintance list. Finally, Limone minimizes the granularity of atomic operations and the set of assumptions about the environment. In this paper we introduce Limone, explain its key features, and explore its capabilities as a coordination model. A universal remote control implementation using Limone provides a concrete illustration of the model and the applications it can support. 1