F. Moller and C. Tofts. A temporal calculus of communicating systems. In Baeten and Klop [BK90], 401--415. (pp 16, 17)  Home/Search   Document Not in Database   Summary   Related Articles   Check

....tics pres ted below. The inferencerules define a mapping ofthis algebra ontoCTMCs (as we will sll9 (# i ) i j P j (j recX. recX. Th prefix(#) P can be considered as th probabilistic version of th timed prefix (t) P thx typically occurs in timed process algebras, like in TCCS [44] or in Timed CSP [50] H. Hermanns and J. P. Katoen The rule forrecurs [ is surs [ wejus recall that P Q X denotes term P in which all (free) occurrences of pro ces variable X in P are replaced by Q. The rule for choicerequires squ explanation.Consana i#I (# i ) i . At execution, thefas[4G ....

....either P or Q independently from (and concurrently to) each other. Due to the memory les property ofCTMCs the behaviour of parallelCTMCs can be interleaved. This is di#erent from adeterminis timesme9]4 where parallel proces4S typically are forced tos91 hronis on the advance of time,as in TCCS [44]. The operationalrules are: i,#) P # (#,i) Q #. Notice that we create new auxiliary labels of the form (i, and (#,i) in order to obtain a multi trans :9s relation. ToundersC] the meaning of the memoryles property in our contextcons1S[ the pro (#) and sd9 os that ....

F. Moller and C. Tofts. A temporal calculus for communicating systems. In CONCUR'90, LNCS 458:401--415. Springer, 1990.

....[27] However, in the literature we see more and more that SOS definitions are decorated with predicates and or negative premises. For example, predicates are used to express matters like (un)successful termination, convergence, divergence [10] enabledness [41] maximal delay, and side conditions [165]. Negative premises are used to describe, e.g. deadlock detection [137] sequencing [55] priorities [24, 65] probabilistic behaviour [139] urgency [58] and various real [136] and discrete time [23, 127, 223] settings. Since predicates and negative premises are so pervasive, and often lead to ....

F. Moller and C. Tofts, A temporal calculus of communicating systems, in Baeten and Klop [26], pp. 401--415.

....where the system ages [NS92] For actions whose duration is such that they cannot be abstracted as instantaneous, it suces to split them into a beginning and an ending action. This principle has lead to many extensions of well known process algebras, such as Timed CSP [RR88, DS94] Timed CCS [MT90, Wan91, Han91], Timed ACP [BB91, BB96, Gro90] and Timed LOTOS [MFV94, CdO94, BLT94b, BLT94a, LL97, LL98, QMdFL94] New timed process algebras have also been proposed, such as TPL [HR95] and ATP [NS94] Even though these languages propose interesting facilities to specify realtime behaviours, very few of them ....

F. Moller and C. Tofts. A temporal calculus of communicating systems. In J.C.M. Baeten and J.W. Klop, editors, CONCUR'90, Theories of Concurrency: Uni cation and Extension, volume 458 of LNCS, pages 401-415. Springer, Berlin, 1990.

.... is an extended and improved version of [LeL93, Le # L94] In particular, the language presented in [Le # L94] has been enhanced and slightly modified to cover full LOTOS (i.e. LOTOS with data types) Among the other proposals that have inspired us, let us mention Real Time CSP [ReR88] TCCS [MoT90] and the Calculus of Real Time Systems [Wan91] A detailed comparison with these proposals, and others, is provided in Section 8. In this paper we present ET LOTOS from a theoretical point of view. Its expressive power as a specification language is further demonstrated in another paper [Le # ....

....(P, #, P#) denoted P# P# in the sequel, may be read as : the process P may perform the action # and thereby be transformed into the process P#. We will sometimes write that the process is in the state P#. We keep this model for ET LOTOS. Following an idea first introduced by Moller and Tofts [MoT90] we simply extend it with a new kind of transitions : timed transitions. More precisely, we extend the set A of actions with D, the time domain. A transition labelled with a time value d, P# P#, means then : the process P may idle for d time units and thereby be transformed into the ....

[Article contains additional citation context not shown here]

Moller, F., Tofts, C. : A temporal calculus of communicating systems. In : J. C. M. Baeten, J. W. Klop, eds., CONCUR '90, Theories of Concurrency : Unification and Extension, LNCS 458. Springer-Verlag, Berlin, 1990, 401--415.

.... modified to cover full LOTOS (i.e. LOTOS with data types) It is the basis of the timed extension of LOTOS currently developed in the ISO#IEC JTC1#SC33 standardization committee [ISO98] It has been inspired in one way or another by several other languages, such as Real Time CSP [ReR88] TCCS [MoT90] and the Calculus of Real Time Systems [Wan91] 2. Overview of the Paper In standard LOTOS, a system can only change state by performing actions, either internally or by interacting with its environment. Since the aim of ET LOTOS is to allow the description of the influence of time on the ....

....(P, #, P#) denoted P# P# in the sequel, may be read as : the process P may perform the action # and thereby be transformed into the process P#. We will sometimes write that the process is in the state P#. We keep this model for ET LOTOS. Following an idea first introduced by Moller and Tofts [MoT90] we simply extend it with a new kind of transitions : timed transitions. More precisely, we extend the set A of actions with D, the time domain. A transition labelled with a time value d, P# P#, means then : the process P may idle for d time units and thereby be transformed into the process ....

[Article contains additional citation context not shown here]

Moller, F. and Tofts, C. : A temporal calculus of communicating systems. In : J. C. M. Baeten, J. W. Klop, eds., CONCUR '90, Theories of Concurrency : Unification and Extension, LNCS 458, Springer -- Verlag, Berlin, 1990, 401--415.

....this problem in this paper. In the untimed setting, bisimulation equivalences have been reasonably successful as notions of implementation between transition systems [BW90, Mil89] Consequently, bisimulation equivalences have also been proposed as implementation relations for the timed setting [BB91, Klu93, MT90, NS94, Yi90]. However, we do not believe that bisimulations will turn out to be very useful as implementation relations in the timed case. The problem is that they do not allow one to abstract in specifications from the often very complex timing behaviour of implementations (see Chapter 10 of [Klu93] for an ....

....that can block the passage of time, and a RATE operation that can change the speed of its argument. On the other hand, there are several operators that have been proposed in the literature that do not fit our format of action transducers, in particular, the CCS style choice operation present in [BB91, MT90, NS94, Yi90]. This operation cannot be expressed as a timed action transducer because the timed trace inclusion relation is not substitutive with respect to it. We briefly consider the design of an appropriate language of operators for describing timing based systems. Such a language should consist of a ....

[Article contains additional citation context not shown here]

F. Moller and C. Tofts. A temporal calculus of communicating systems. In Baeten and Klop [BK90], pages 401--415.

....i.e. it is not suitable to take into account real time aspects. This is not the purpose of our formalism. We consider insertion of these properties as another level of abstraction. It is possible to introduce them in a refinement step following this specification step. Another idea is to use TCCS [10, 39] (T for Timed) instead of CCS. We remind that in CCS the synchronization is possible only between two agents. We have studied the modification of this kind of synchronization to another one. After much thoughts on the possible choices concerning the synchronization types: between two agents, ....

....execute themselves between two units of logical time to preserve the specification consistency. These hypotheses are non formal, then that could lead to inconsistencies. This drawback is due to the lack of real time constraints possibilities. A solution would be using a version of timed CCS [10, 39] in order to express the possible temporal aspects in a formal way. This is one of the main direction for future works. ClockAux(t: Instant, nbt: Nat, nbat: Nat) if (nbt = 1) then incClock.Clock(t, nbt, nbt) if not (nbt = 1) then incClock.ClockAux(t, nbt, nbat 1) The tester has ....

[Article contains additional citation context not shown here]

F. Moller and C. Tofts. A Temporal Calculus of Communicating Systems. In J. C. M. Baeten and J. W. Klop, eds., Theories of Concurrency: Unification and Extension (CONCUR'90), volume 458 of Lecture Notes in Computer Science, pages 401--415, The Netherlands, 1990. Springer-Verlag.

....limiting the complexity of the method, this also reduces its expressiveness. As discussed in Section 3.4, an explicit notion of time is required to achieve a satisfactory speci cation of real time behaviour. TCCS is a process algebras with explicit time, and thus suitable for real time systems [MT90] It is based on CCS, but with two additional constructs. The term (t) P denotes a process that behaves as P after exactly t units of time, and :P behaves as P but is willing to wait any amount of time before actually proceeding. These constructs can be used to de ne useful real time concepts ....

Faron Moller and Chris Tofts. A temporal calculus of communicating systems. In J. C. M. Baeten and J. W. Klop, editors, CONCUR '90: Theories of Concurrency: Uni cation and Extension, volume 458 of Lecture Notes in Computer Science, pages 401-415, Amsterdam, The Netherlands, 27-30August 1990. Springer-Verlag.

....systems require considerable refinement of the process algebras, in both the algebraic notation as well as the underlying semantic models. Considerable effort in this latter area has resulted in a large collection of real time versions of untimed process al gebras, such as CCS (e.g. M83, MT90, W91b, HR95, H91, FZ95] CSP (e.g. RR88, S91, DS95, S96] and ACP (e.g. IBB91, NS94] Ever since the boom of the mobile communica tions industry in the 90 s, various mobile devices have been manufactured. As a result, mobile computing has gained more and more attention over the past decade. ....

F. Moller and C. Torts, "A Temporal Cal- culus of Communicating Systems", Proceedings of CONCUR'90, LNCS 458, p401-415, 1990.

....address this problem in this paper. In the untimed setting, bisimulation equivalences have been reasonably successful as notions of implementation between transition systems [6, 34] Consequently, bisimulation equivalences have also been proposed as implementation relations for the timed setting [4, 23, 35, 38, 47]. However, we do not believe that bisimulations will turn out to be very useful as implementation relations in the timed case. The problem is that they do not allow one to abstract in specifications from the often very complex timing behavior of implementations (see Chapter 10 of [23] for an ....

....that can block the passage of time, and a RATE operation that can change the speed of its argument. On the other hand, there are several operators that have been proposed in the literature that do not fit our format of action transducers, in particular, the CCS style choice operation present in [4, 35, 38, 47]. This operation cannot be expressed as a timed action transducer because the timed trace inclusion relation is not substitutive with respect to it. We briefly consider the design of an appropriate language of operators for describing timing based systems. Such a language should consist of a ....

[Article contains additional citation context not shown here]

F. Moller and C. Tofts. A temporal calculus of communicating systems. In Baeten and Klop [5], pages 401--415.

.... I II) and as [43] 1 Introduction Most of the existing semantic models, languages and logics for describing and reasoning about timing based systems implicitly view an execution as an alternating sequence of instantaneous discrete actions and continuous phases during which time advances [2, 5, 7, 8, 9, 11, 14, 17, 20, 25, 26, 27, 48, 50, 52, 54, 61, 62]. To each system described in any of these formalisms one can associate a transition system or automaton consisting of (1) a set of states, 2) a set of initial states, 3) a set of discrete actions, 4) a set of discrete steps s Gamma s asserting that from state s the system can ....

....believe that timed automata, defined in this way, provide an excellent basis for defining and studying behavioral preorders and simulation proof techniques for timing based systems. Since timed automata can be viewed as an underlying semantic domain for any of the models, languages and logics of [2, 5, 7, 8, 9, 11, 14, 17, 20, 25, 26, 27, 48, 50, 52, 54, 61, 62], all the results that we obtain for timed automata carry over directly to those settings. For convenience, we use R as our domain of times in this paper. The need for densetime models has been well discussed in [4] However, for the purpose of generality we could have parameterized our timed ....

[Article contains additional citation context not shown here]

F. Moller and C. Tofts. A temporal calculus of communicating systems. In Baeten and Klop [10], pages 401--415.

....quantitative time, because time constraints of such systems are frequently altered depending on implementations. In such cases, we must guarantee that the system s essential behaviour would not be changed. In the latest years many languages have been proposed to describe real time prop erties [5 10]. For example, timed extensions of CCS[5 7] introduced several primi tive operators such as delay and timeout operators to describe real time properties. However, in these languages, even describing a simple time constraint that some action has to be done within a given time interval yields to a ....

....of such systems are frequently altered depending on implementations. In such cases, we must guarantee that the system s essential behaviour would not be changed. In the latest years many languages have been proposed to describe real time prop erties [5 10] For example, timed extensions of CCS[5 7], introduced several primi tive operators such as delay and timeout operators to describe real time properties. However, in these languages, even describing a simple time constraint that some action has to be done within a given time interval yields to a complicated descrip tion. Although ....

[Article contains additional citation context not shown here]

F. Moller and C. Tofts, "A temporal calculus of communicating systems," in Proc. of CONCUR '90, vol. 458 of Lecture Notes in Computer Science, pp. 401-415, Springer-Verlag, 1990.

....tasks are critical, in the sense that they must be executed urgently once they become enabled. Thus, in the last years several extensions of the classical models to describe concurrent systems have been defined in order to incorporate this factor: we have timed extensions of CSP [17, 13, 19] CCS [11], and LOTOS [15] Bolognesi and Lucidi [2] have defined another timed extension of LOTOS, which includes an operator for the specification of urgent interactions. Hansson and Jonsson have defined another timed and probabilistic extension of CCS [7, 6] by including a time out operator. In fact, ....

F. Moller and C. Tofts. A temporal calculus of communicating systems. Proceedings CONCUR 90, Lecture Notes in Computer Science, (458):401--415, 1990.

....systems. In recent years process algebras which involve time have been proposed to fulfill the need for formalisms able to deal with quantitative time aspects of systems. The option to represent time by non negative reals and to have time stamps on actions is taken into account in [2] for ACP, in [9] for CCS and in [1] for CSP. Another option is to divide time into slices, thus giving the possibility to use an implicit or explicit time stamping mechanism that provides each action with the index of the time slice in which it occurs. This has been developed for the case of ACP in [3] Frame ....

F. Moller and C. Tofts. A temporal calculus of communicating systems. In CONCUR'90, LNCS. Springer, 1990.

....are critical, in the sense that they must be executed urgently once they become enabled. Thus, in the last years several extensions of the classical models to describe concurrent systems have been de ned in order to incorporate this factor: we have timed extensions of CSP [RR88,Ort90,Sch95] CCS [MT90], and LOTOS [QAdF89] Bolognesi and Lucidi [BL91] have de ned another timed extension of LOTOS, which includes an operator for the speci cation of urgent interactions. Hansson and Jonsson have de ned another timed and probabilistic extension of CCS [HJ90,Han92] by including a time out ....

F. Moller and C. Tofts. A temporal calculus of communicating systems. Proceedings CONCUR 90, Lecture Notes in Computer Science, (458):401{ 415, 1990.

....theory has recently been devoted to the development of extensions of standard process algebras like CCS [16] CSP [11] and ACP [3] with constructs allowing for the modelling of timing aspects in the behaviour of processes. By now, most process algebras have a timed counterpart (see, e.g. [1, 6, 18, 21]) and the development of results and techniques for these languages is becoming comparable with that for the standard process description languages. For example, complete axiomatizations of behavioural On leave from School of Cognitive and Computing Sciences, University of Sussex, Brighton BN1 ....

....Research in Computer Science, Centre of the Danish National Research Foundation. Supported by SERC project GR H 16537. Additional funding was received from EC BRA 7166 concur2. Email: alanje cogs.susx.ac.uk. 1 congruences for subsets of timed process algebras have been presented in, e.g. [10, 14, 18, 22] showing that behavioural congruences which deal with timing considerations are as mathematically tractable as the standard untimed ones. Two of the most beautiful results in the theory of process algebras are the complete axiomatizations of strong bisimulation equivalence and observational ....

[Article contains additional citation context not shown here]

F. Moller and C. Tofts. A temporal calculus of communicating systems. In Baeten and Klop [2], pages 401--415.

....using predicates [9] However, in the literature SOS de nitions are often decorated with predicates and or negative premises. For example, predicates are used to express matters like (un)successful termination, convergence, divergence [3] enabledness [14] maximal delay, and side conditions [42]. Negative premises are used to describe, e.g. deadlock detection [38] sequencing [17] priorities [7, 21] probabilistic behaviour [39] urgency [19] and various real [37] and discrete time [6, 35] settings. Since predicates and negative premises are so pervasive, and often lead to cleaner ....

F. Moller and C. Tofts, A temporal calculus of communicating systems, in Baeten and Klop [8], pp. 401-415.

....discussed below. 3.4.3 Timed extensions of process algebras Considerable e#ort has been put into developing process algebras which explicitly represent quantitative time. The timed process algebras are generally derived as extensions of untimed process algebras(see Section 2. 5) Thus Temporal CCS [48] and Timed CCS [68] derive from CCS [46] TCSP [53] from CSP [56] U LOTOS [8] from LOTOS [6] and TPL [30] is derived from Hennessy s Acceptance Trees [28] In Section 3.4.1 the distinction between discrete and dense (ie infinitely divisible) representations of time was noted. This distinction is ....

F. Moller and C. Tofts. A temporal calculus of communicating systems. In Baeten and Klop [3], pages 401--415.

No context found.

F. Moller and C. Tofts. A temporal calculus of communicating systems. In Baeten and Klop [BK90], 401--415. (pp 16, 17)

No context found.

F Moller and C Tofts. A temporal calculus of communicating systems. Technical Report ECS-LFCS-89-104, Edinburgh University, December 1989.

No context found.

F. Moller and C. Tofts. A temporal calculus of communicating systems. In J.C.M. Baeten and J.W. Klop, editors, Proceedings CONCUR 90, Amsterdam, pages 401-- 415, Springer-Verlag, 1990.

No context found.

F. Moller, C. Tofts, A temporal calculus of communicating systems, in: J.C.M. Baeten, J.W. Klop (Eds.), CONCUR'90, Lecture Notes in Computer Science, vol. 458, Springer, Berlin, 1990, pp. 401--415.

No context found.

F. Moller, C. Tofts, A temporal calculus of communicating systems, in: Proceedings of the CONCUR'90, 1990, pp. 401--415.

No context found.

F Moller and C Tofts. A temporal calculus of communicating systems. Technical Report ECS-LFCS89 -104, Edinburgh University, December 1989.

No context found.

F. Moller, C. Tofts, A temporal calculus of communicating systems, in: J.C.M. Baeten, J-W. Klop (Eds.), Concur'90: Theories of Concurrency --- Uni#cation and Extension, Lecture Notes in Computer Science, vol. 458, Springer, Berlin, 1990, pp. 401-- 415.

First 50 documents  Next 50

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC