R. Milner, J. Parrow, and J. Walker. A Calculus of Mobile Processes Part I and II. Information and Computation, 100:1--77, 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... calculus has previously shown its ability to express several object oriented features within the calculus and it is also possible to encode the calculus[Abr89] In this paper we shall describe an encoding of the simplest version of the calculus into an asynchronous version of the calculus[PW92] and investigate the properties of this encoding. In particular, the encoding is sound under the operational semantics of the calculus. We also show that Address: Dep. of Computer Science, Aalborg University, Frederik Bajersvej 7, 9220 Aalborg, Denmark. Email: fhans,kleistg cs.auc.dk 1 our ....

....= l = y)y:l ( x)x] then a :l ; a :l ( x)x ; a The object a shows how we can get infinite behaviour through the use of self variables. The object a shows how an object can modify itself by performing a method override on a self variable. 3 The asynchronous calculus The calculus [PW92] has previously shown its ability to encode both the calculus [Mil92] and certain object oriented languages [Wal95, San96] In [Wal95] Walker encoded a variant of the programming language POOL [Ame89] into the calculus and in [San96] Sangiorgi investigates another encoding of the calculus into ....

Robin Milner Joachim Parrow and David Walker. A calculus of mobile processes --- part i and ii. Information and Computation, 100:1--77, 1992.

....ciudad universitaria Mel endez, Cali, Colombia GERARD ASSAYAG assayag ircam.fr IRCAM, 1 pl Igor Stravinski, 75004 Paris, France Abstract. We propose PiCO, a calculus integrating concurrent objects and constraints, as a base for music composition tools. In contrast with calculi such as [5] [9] or TyCO [16] both constraints and objects are primitive notions in PiCO.InPiCO a base object model is extended with constraints by orthogonally adding the notion of constraint system found in the # calculus [12] Concurrent processes make use of a constraint store to synchronize communications ....

J. P. R. Milner and D. Walker (1992). "A Calculus of Mobile Processes, Parts I and II." Journal of Information and Computation, 100: 1--77.

....ciudad universitaria Mel endez, Cali, Colombia Gerard Assayag (assayag ircam.fr) IRCAM, 1 pl Igor Stravinski, 75004 Paris, France Abstract. We propose PiCO, a calculus integrating concurrent objects and constraints, as a base for music composition tools. In contrast with calculi such as [5] [9] or TyCO [16] both constraints and objects are primitive notions in PiCO. In PiCO a base object model is extended with constraints by orthogonally adding the notion of constraint system found in the ae calculus [12] Concurrent processes make use of a constraint store to synchronize ....

R. Milner, J. P. and D. Walker: 1992, `A Calculus of Mobile Processes, Parts I and II'. Journal of Information and Computation 100, 1--77.

....Out Ground Operations System) as a prototype for an unattended ground operations center in the area of control center automation [LO97] The system will integrate present technologies that exist at NASA GSFC with emerging technology via the use of autonomous agents. We show how the p calculus [MPW92], a calculus for communicating systems where one can express systems of processes that have changing communication structure, can be used to model aspects of multi agent systems. The p calculus is a process algebra; other examples include CCS [Mi89] and CSP [Ho85] Process algebras are term ....

....the fault. FIRE to Pager: Requests that the Pager agent locate the UIFA. Pager to UIFA: Signals the UIFA agent to resolve a fault. UIFA to Pager: Commands the Pager agent to stop paging. UIFA to FIRE: Responds to the FIRE agent that it will resolve the fault. 3. The p Calculus The p calculus [MPW92] can be used to model a system that consists of processes that interact with each other, and whose environment is constantly changing. The p calculus is available in two basic styles: the monadic calculus [MPW92] where exactly one name is communicated at each synchronization, and the polyadic ....

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Milner, R., Parrow, J., and Walker, D. "A Calculus of Mobile Processes, Parts I and II." Journal of Information and Computation, Vol. 100, 1992, 1-77.

....radical step in this direction is to think of processes just as agents that communicate each others channel names as values. In this way processes are virtually passed by sending the name of a (private) channel to the receiver, thus giving access to the passed process: this is Milner s calculus [51]. In the latter case, functions and functional application disappear from the calculus syntax, and they are simulated in a rather complex way. In this paper we advocate a third approach to the problem of the mathematical study of relevant aspects of concurrent functional languages, which, in some ....

R. Milner, J.G. Parrow, D.J. Walker, "A Calculus of Mobile Processes, Parts I and II", Info. and Comp. 100, 1992, 1-40, 41-77.

....the pure lambda calculus about termination. For instance, you cannot define the convergency test (see section 2) Such an operator is used to show that Abramsky s canonical domain for the lazy lambda calculus and Milner s encoding into the calculus do not induce fully abstract models (we refer to [10, 11] for a detailed exposition of the encoding and of calculus) Moreover, since applicative bisimulation derives from equivalence ideas developed for frameworks of reactive and concurrent systems, one might consider appealing the introduction of parallel operators. Various enrichments of the ....

....by Milner s encoding into the calculus Our starting point is the equivalence induced on the lambda terms by Milner s encoding into the calculus . Let [ M ] denote the encoding of the term M and the calculus s observational equivalence. To be precise, according to the terminology in [11] we should also say which version of the observational equivalence we mean, if the late or the early, ground or not ground. We do not because on the encoding of closed lambda terms all such versions coincide. Definition 4 Let M;N 2 (X ) then M N if [ M ] N ] In such a case we say that ....

R., Milner, J.G., Parrow, and D.J., Walker, "A Calculus of Mobile Processes, Parts I and II", Report ECS-LFCS-89-85 and-86, Computer Science Department, Edinburgh University, 1989, to appear in Journal of Information and Computation.

....on communication as the primitive interaction mechanism and builds a complete mathematical model from which concurrent programming languages can be derived. Even these are pre dated by the work of Carl Petri and his Petri Net theory of concurrency (see for example [Pet81] however. The p calculus [Mil92] extends process algebra to allow for dynamic systems with a changing topology and has gained a lot of attention for use in modelling the dynamics of concurrent object systems [Nie95] for example in the PICT language [Lum96] Our colleague, Xiaogang Zhang, is working on a class based model of ....

Milner R., Parrow J. and Walker D., "A Calculus of Mobile Processes (parts I and II)", Information and Computation, Vol 100, pp1-77, 1992

....on communication as the primitive interaction mechanism and builds a complete mathematical model from which concurrent programming languages can be derived. Even these are pre dated by the work of Carl Petri and his Petri Net theory of concurrency (see for example [Pet81] however. The p calculus [Mil92] extends process algebra to allow for dynamic systems with a changing topology and has gained a lot of attention for use in modelling the dynamics of concurrent object systems [Nie95] for example in the PICT language [Lum96] Our colleague, Xiaogang Zhang, is working on a class based model of ....

Milner R., Parrow J. and Walker D., "A Calculus of Mobile Processes (parts I and II)", Information and Computation, Vol 100, pp1-77, 1992

....counter, but this time the counter will be updated at the events arrival and start. Note that actions and guards are executed in mutual exclusion which allows a safe update of the variables execWriteOps and execReadOps. 3 Pict Pict is a language based on the polyadic p calculus [5] where the basic entities are processes and channels. The following paragraphs constitute an informal presentation of the language that should help the reader to understand section 4. More information can be found in [6] 3.1 Channels and types A channel is a port over which one process may ....

....operators New infix operators can be introduced in the language. They are defined exactly like functions but with their name enclosed in parentheses: def ( n,m] m n) 2 run printi (5 4) An infix operator can also be called using the usual syntax def ( n,m] m n) 2 run printi ( [5,4]) 3.4.4 Sequencing Assume we want to print the number 3 followed by the number 4 in that order. We cannot use a program like: run printi 3 printi 4 because we cannot tell which process will communicate first. Pict provides a simple way to call functions in sequence. The only requirement put ....

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Robin Milner, Joachim Parrow and David Walker, "A Calculus of Mobile Processes, Parts I and II," Reports ECS-LFCS-89-85 and-86, Computer Science Dept., University of Edinburgh, March 1989.

..... This multiset does not discriminate physical locations and realizes hereby ubiquitous information objects. Only the channels define a structure on top of these agents, and define the equivalence of space through those channels. Note, that the concept of a channel is in contrast to, e.g. [11] implicit there is no construct channel : any of the ubiquitous information objects may communicate provided it is stated in the transition rules. Note, that our approach is compositional. Agents and channels can be specified in different formalisms and can be composed to the declarative ....

....Logic in describing architectures for virtual distributed environments and to [19] for relations of Rewriting Logic with other formalisms. 3] presents an an introduction to Labelled Deductive systems. Multi agent systems can be formalized at different levels of abstraction: the calculus [11] models distributed systems as a collection of mobile agents, Troll [20] ofi [21] are examples for object oriented, formal approaches for describing distributed systems. Particular to our approach is the formalization not only of the domain of discourse to be represented on the medium, but also ....

R. Milner, J. Parrow, and D. Walker, "A calculus of mobile processes, Parts I and II," Information and Computation, vol. 100, no. 1, pp. 1--40 and 41--77, 1992.

....research within theoretical computer science has been directed towards this kind of systems. The emphasis has mainly been on semantic issues; in particular, how should such systems be represented faithfully and fully abstracted. This has, for example, lead to the development of the Pi calculus [Milner et al. 1992], and to new refinements of the Actor model [Agha et al. 1997] Most of the early proposals have a strong operational flavour. More recent denotational approaches [Jagadeesan,1995] Stark,1996] are rather technical, and in most cases directed towards the Pi calculus. The above mentioned research ....

R. Milner, J. Parrow, D. Walker, A Calculus of Mobile Processes part I and II, Information and Computation, 100:1-77, 1992.

....usually the service customer. Next, the new service is decomposed in order to find its relevant components and connectors. Then, components and connectors are formally specified using a formalism for protocol verification purpose. We have works using LOTOS [12] and also using p calculus [18 ] formalism [19 ] Once we are sure that the interaction patterns between components and connectors are validated the framework generates templates written in Java. We want to point out that these templates have the pattern interactions validated. Therefore, the service designer has to ....

Milner R., Parrow J., Walker D., "A Calculus of Mobile Processes, Parts I and II". Journal of Information and Computation, vol. 100, 1992, pp. 1-77.

....above) into our formal foundation. The design of the composition language is informed by results from the theoretical study of communicating processes. 3] for example, show that 2 way communication interfaces are sufficient for implementing n way synchronization. The notion of bisimilarity (see [20]) could serve as foundation for a component and interaction type system. Secondly, we have to be aware that total flexibility is not necessarily a desirable goal, especially so in CSCW where several users might potentially be affected by a tailoring operation. Thus, it should be possible ....

Milner, R.,Parrow, J., and Walker, D., "A calculus of mobile processes, Parts I and II," Journal of Information and Computing, vol. 100, pp. 1-77, 1992.

....properties of the systems so described. The use of formal methods could help us to avoid these limitations. Formal specifications have a precise meaning derived from the semantics of the notation used and they admit several forms of reasoning. In particular, we propose the use of the calculus [9] for the specification of software architectures. The calculus can express directly the mobility, making easier the specification of dynamic systems. Besides, its formal basis allows the analysis of the specifications and also the development of automated verification tools [15] One of the ....

....the possibility of direct expression of mobility in calculus makes easier the specification of ports and roles. In fact, as it is stated in [8] formalisms like CCS or CSP do not seem the most appropriate for the description of evolving or dynamic structures. 3 The calculus The calculus [9] is a process algebra derived from CCS. It is specially suited for the description and analysis of dynamic systems. A system is specified in the calculus as a collection of processes or agents which interact by means of links or names (we denote by N the set of names) The restriction of the ....

R. Milner, J. Parrow and D. Walker. "A Calculus of Mobile Processes, Parts I and II". Journal of Information and Computation, vol. 100, 1992, pp. 1--77.

....that (P, Q) R implies: i) P = if and only if Q = ii) for all a A: a) P a P implies Q , Q a Q and (P , Q ) R. b) Q a Q implies P , P a P and (P , Q ) R. The strong and weak semantic equivalences coincide with the strong and weak equivalence (cf. Milner [11]) respectively if the first of the two requirements (i) is dropped. In other words, if two processes P and Q are free of the undefined state p then (i) P Q implies P and Q are strongly equivalent; ii) P Q implies P and Q are weakly equivalent. 9 charge1, charge2 prepay1, prepay2 activate ....

R. Milner, J. Parrow, and D. Walker, "A Calculus of Mobile Processes Part I and II," : University of Edinburgh, June 1989.

.... process calculi and calculi (i.e. where function application is analogous to communication and functions are first class communicable values) The original work on extending CCS to accommodate label passing is by Engberg [15] More recently, there has been the development of the calculus [25], Thomsen s Calculus of Higher Order Communicating Systems (CHOCS) 38] Nielsen s calculus with first class processes [28] Boudol s proposal for a concurrent calculus [8] and Berry and Boudol s Chemical Abstract Machine (CHAM) 7] The most important contributions in these developments appear ....

....a by n : a) The third allows us to discard a restriction of an unused name (fn(a) is the set of free names in a) The fourth equation tells us that the order of restriction is unimportant. The fifth equation allows us to expand the scope of a restriction to nearby agents (called scope extrusion [25]) if the restricted name is new. The last three equations define ff convertibility for agents. They are needed for substituting local names by globally unique names prior to scope extrusion. O.M. Nierstrasz 6 Definition 3 Communication offers, denoted by c Gamma , where c is either v (for ....

R. Milner, J. Parrow and D. Walker, "A Calculus of Mobile Processes, Parts I and II," Reports ECS-LFCS-89-85 and-86, Computer Science Dept., University of Edinburgh, March 1989.

....dynamically instantiated, channel names cannot be communicated and no new channel names can be dynamically introduced. Functional abstraction cannot be modeled, and it is also not possible to pass process expressions as values. These technical shortcomings where attacked by various researchers [7] [23] [25] 36] 39] and have culminated in the p calculus, a calculus of mobile processes in which channel names can be communicated and newly introduced using rules analogous to those for the l calculus to avoid capture of names. Although the p calculus only allows for the communication of names ....

Robin Milner, Joachim Parrow and David Walker, "A Calculus of Mobile Processes, Parts I and II," Reports ECS-LFCS-89-85 and-86, Computer Science Dept., University of Edinburgh, March 1989.

....use either as far as their behaviour is concerned. Over the years, there have been many studies of behaviour equivalence. Commonly used behaviour equivalences in the literature include trace equivalence [32] failure equivalence [5, 19] testing equivalence [13] observational (weak) equivalence [30] and strong equivalence [30] Among these, observational and strong equivalences are popularly used to distinguish behaviours of communicating processes [30] Strong Equivalence Strong equivalence is widely accepted as the strongest equivalence relation of interest to the theory of concurrency ....

....behaviour is concerned. Over the years, there have been many studies of behaviour equivalence. Commonly used behaviour equivalences in the literature include trace equivalence [32] failure equivalence [5, 19] testing equivalence [13] observational (weak) equivalence [30] and strong equivalence [30]. Among these, observational and strong equivalences are popularly used to distinguish behaviours of communicating processes [30] Strong Equivalence Strong equivalence is widely accepted as the strongest equivalence relation of interest to the theory of concurrency [32, 36] It is generally ....

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R. Milner, J. Parrow and D. Walker. A Calculus of Mobile Processes Part I and II, Technical Report, University of Edinburgh, June 1989.

....has been on studying the equivalences for pure processes where communication does not involve the passing of data values. However, within the past few years there has been renewed interest in the study of value passing as a consequence of the emergence of the 7r calculus. Here Milner et al. [6] have determined two variants of the notion of bisimulation, late and ear ly bisimilarity, differing in the assumption of when a data value is instantJared. Most recently Sangiorgi [7] has proposed a new notion of bisimulation equivalence which he calls open bisimilarity. Sangiorgi formulates a ....

Robin Milner, Joachim Parrow, and David Walker. A calculus of mobile processes part I and II. Technical Report ECS-LFCS-89-85 and-86, Department of Computer Science, University of Edinburgh, 1989.

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R. Milner, J. Parrow, and J. Walker. A Calculus of Mobile Processes Part I and II. Information and Computation, 100:1--77, 1992.

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R. Milner, J. Parrow, and D. Walker. A Calculus of Mobile Processes -- parts I and II. Journal of Information and Computation, 100:1--77, 1992. Available as technical report: ECS-LFCS-89-85/86, University of Edinburgh, UK.

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R. Milner, J. Parrow, and J. Walker. A Calculus of Mobile Processes Part I and II. Information and Computation, 100:1--77, 1992.

No context found.

R. Milner, J.G. Parrow, D.J. Walker, "A Calculus of Mobile Processes, Parts I and II", Report of ECS-LFCS-89-85 and 86, Edinburgh Un., 1989.

No context found.

R. Milner, J.G. Parrow, D.J. Walker, "A Calculus of Mobile Processes, Parts I and II", Info. and Comp. 100, 1992, 1-40, 41-77.

No context found.

R. Milner, J.G. Parrow, D.J. Walker, "A Calculus of Mobile Processes, Parts I and II", Report of ECS-LFCS-89-85 and 86, Edinburgh Un., 1989.

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