Ichiro Satoh and Mario Tokoro, "A Timed Calculus for Distributed Object with Clocks" Proceedings of the 7th European Conference on Object Oriented Programming, pp. 326345, Springer-Verlag, Kaiserslautern, Germany, July 1993.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....our requirements concerning component composition, because compatibility criteria must be defined, and interfaces must correctly reflect encapsulated behaviors. 4. Numerous extensions have been proposed which are of particular interest in our area, such as distributed real time processes calculi [2] [3] The key issue addressed in this paper is the use of a formal calculus to model applications constructed and configured with Olan. Olan rely on a component based model that describes applications as interconnections of components, with no restrictions on the execution model of those ....

Ichiro Satoh and Mario Tokoro, "A Timed Calculus for Distributed Object with Clocks" Proceedings of the 7th European Conference on Object Oriented Programming, pp. 326345, Springer-Verlag, Kaiserslautern, Germany, July 1993.

....N in Machine N and thus we can predict the execution of programs with a given number of processors. From the above expression we know that, for example, let N = 2, then put (or get) method call may occasionally timeout and the execution of the program described in Figure 11 takes from 14 t stat to 16 t stat time units. The final content of variable Y in Writer s instance and that of Reader s one are non deterministic. Let N 3, then no method calls timeouts and the execution of the program takes from 12 t stat to 13 t stat time units (N = 3) or 12 t stat time units (N 4) The final content ....

....to define and compare various real time languages through this semantics framework. Also, the semantics implicitly assumes a global clock, whereas in distributed systems such a global clock cannot inherently be realized. We have already developed a process calculus based on non global clocks in [16] We plan to investigate a semantics for distributed real time programming languages by using the calculus. Acknowledgements We are grateful to Vasco Vasconcelos (Keio University) for helpful comments on an earlier version of this paper. We would like to thank anonymous referees for providing ....

Satoh, I., and Tokoro, M., A Timed Calculus for Distributed Objects with Clocks, Proceedings of ECOOP'93, LNCS 707, p326-345, Springer-Verlag, 1993.

....our requirements concerning component composition, because compatibility criteria must be defined, and interfaces must correctly reflect encapsulated behaviors. 4. Numerous extensions have been proposed which are of particular interest in our area, such as distributed real time processes calculi [2] [3] RR n 3231 4 Jean Yves Vion Dury, Luc Bellissard, Vladimir Marangozov The key issue addressed in this paper is the use of a formal calculus to model applications constructed and configured with Olan. Olan rely on a component based model that describes applications as interconnections of ....

Ichiro Satoh and Mario Tokoro, "A Timed Calculus for Distributed Object with Clocks" Proceedings of the 7th European Conference on Object Oriented Programming, pp. 326-345, Springer-Verlag, Kaiserslautern, Germany, July 1993.

....requirements concerning component composition, because compatibility criteria must be defined, and interfaces must correctly reflect encapsulated behaviors. 2 4 numerous extensions have been proposed which are of particular interest in our area, such as distributed real time processes calculus [2], 3] The key issue addressed in this paper is the use of a formal calculus to model applications constructed and configured with Olan. Olan rely on a component based model that describes applications as interconnections of components, with no restrictions on the execution model of those ....

Ichiro Satoh and Mario Tokoro, "A Timed Calculus for Distributed Object with Clocks" Proceedings of the 7th european Conference on Object Oriented Programming, pp. 326-345, Springer-Verlag, Kaiserslautern, Germany, July 1993.

....to define and compare various real time languages through this semantics framework. Also, the semantics implicitly assumes a global clock, whereas in distributed systems such a global clock cannot inherently be realized. We have already developed a process calculus based on non global clocks in [16]. We plan to investigate a semantics for distributed real time programming languages by using the calculus. Acknowledgements We are grateful to Vasco Vasconcelos (Keio University) for helpful comments on an earlier version of this paper. We would like to thank anonymous referees for providing ....

Satoh, I., and Tokoro, M., A Timed Calculus for Distributed Objects with Clocks, Proceedings of ECOOP '93, LNCS 707, p326-345, Springer-Verlag, 1993.

....Objects # Ichiro Satoh ## and Mario Tokoro ### Department of Computer Science, Keio University 3 14 1, Hiyoshi, Kohoku ku, Yokohama, 223, Japan Abstract. This paper presents a framework of specification and verification for distributed real time object oriented systems. An earlier paper [17] introduced a process calculus to describe distributed objects using local clocks. However, it is appropriately based on synchronous communication and thus cannot su#ciently model asynchronous communication in distributed systems. In this paper we propose a new process calculus with the ability to ....

....Systems) with the ability to express communication delay, asynchronous message passing, and delayed processing. It allows us to describe temporal and behavioral properties of remotely located real time objects and their asynchronous interactions with communication delay. In earlier papers [16, 17] the authors introduced timed extended process calculi, called RtCCS and DtCCS, for real time concurrent and distributed object oriented computing. Unfortunately, these calculi are based on synchronous communication and thus cannot provide any general framework for asynchronous interactions among ....

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Satoh, I., and Tokoro, M., A Timed Calculus for Distributed Objects with Clocks, Proceedings of ECOOP'93, LNCS 707, p326-345, July, 1993.

....the required precision of time information is finer than the intervals of clock synchronizations, di#erences and uncertainties among clocks may lead cooperations among distributed processes to timing failures. 1 This chapter is a modified version of an article that has been published earlier in [66, 68]. 54 CHAPTER 4. LOCALITY IN TIME 55 We need to analyze the influences of the inaccuracies of clocks upon the behavioral and temporal properties of distributed systems. A number of computing models for distributed systems have already been proposed. However, most of them are essentially ....

I. Satoh and M. Tokoro. A Timed Calculus for Distributed Objects with Clocks. In Proceedings of European Conference on Object Oriented Programming (ECOOP '93), volume 707 of Lecture Notes in Computer Science, pages 326--345. Springer-Verlag, July 1993.

....local clocks. In Section 3, we define the syntax and the operational semantics of DtCCS. Section 4 presents the concept of timed bisimilarity based on local time and studies its basic properties. The final section contains some concluding remarks. However, this paper is an abbreviated version of [15] and we leave the further details on DtCCS and all the proofs to [15] 2 Distributed Timed CCS In this section, we describe our basic idea of time in distributed computing and a brief introduction to our formalism, and then we formally define the formalism. First, we present our two assumptions ....

....semantics of DtCCS. Section 4 presents the concept of timed bisimilarity based on local time and studies its basic properties. The final section contains some concluding remarks. However, this paper is an abbreviated version of [15] and we leave the further details on DtCCS and all the proofs to [15]. 2 Distributed Timed CCS In this section, we describe our basic idea of time in distributed computing and a brief introduction to our formalism, and then we formally define the formalism. First, we present our two assumptions for time in distributed computing. ffl All processors in a ....

[Article contains additional citation context not shown here]

Satoh, I., A Timed Calculus for Distributed Objects with Clocks, To appear in Proc. European Conference on Object-Oriented Programming (ECOOP'93), LNCS, July, 1993.

....1. Air Traffic Control System 1 active class ControlTower 2 protected: 3 . 4 public: 5 EmData emergencyrunway( 6 within(0t200ms) timeout(recover) 7 EmData emergencyinfo( 8 within(0t500ms) timeout(recover) 9 . 10 activity: 11 protocol ProtAOI, ProtTAOI, ProtATAOI; 12 slave[5] emergencyrunway( emergencyinfo( 13 ; Fig. 2. Definition of Class ControlTower We suppose the situation shown in Figure 1. The airplane suffers a malfunction in flight. Then, immediately, the airplane object calls a method emergency( In emergency( the airplane tries to access the ....

....rate. The differences between clocks may cause interactions between objects to fail. Therefore, we need a formalism for reasoning about such locally temporal properties in distributed real time programs. Satoh and one of the authors proposed such a formalism, called DtCCS, an extension of RtCCS [5]. Here, we will give an overview of it. Before giving an exposition of DtCCS, we first present assumptions on the modeling of local time. If the relative motion of all processors is negligible, Einstein s Theory of Relativity tells us that the passage of physical time in every processor elapses ....

[Article contains additional citation context not shown here]

Satoh, I., and Tokoro, M., A Timed Calculus for Distributed Objects with Clocks, Proceedings of ECOOP'93, July, 1993.

....There have indeed been several process calculi for distributed systems. They are extensions of existing process calculi with some features of distributed computing: causality between events (e.g. 6] location information (e.g. 4] port passing mechanism (e.g. 8, 11] and local time (e.g. [17]) but none addresses the issue of communication delay. Also, there have been several temporal extensions of process calculi for synchronous communication, for example [7, 13, 14, 16, 20, 22] Among these, Moller and Tofts in [13] studied a preorder relating timed processes with respect to speed. ....

....follow hereafter. Definition 2.1 ffl Let M be a non empty infinite set of message names, ranged over by a,b, ffl Let Loc be an infinite set of location name, ranged over by , 1 , 2 , ffl Let T denote the set of the positive reals including 0. 3 By using the method developed in [17], we can express multiple and inaccurate clocks. 4 The notion of process location in this paper is introduced only to express temporal distance between locations; we do not intend to investigate the notion itself. ffl Let D Loc2Loc T be the set of communication delay functions, ranged over ....

Satoh, I., and Tokoro, M., A Timed Calculus for Distributed Objects with Clocks, Proceedings of 8th European Conference on Object Oriented Programming, LNCS 707, p326-345, Springer-Verlag, July, 1993.

....same rate. Differences among clocks may lead interactions among objects to failure. Therefore, we need a formalism for reasoning about such locally temporal properties in distributed real time programs. We here propose such a formalism, called DtCCS, by extending RtCCS, but we leave its detail to [4]. Before giving an exposition of DtCCS, we first present assumptions on the modeling of local time. If relative motion of all processors is negligible, from Einstein s Relativity, the passage of physical time in every processor elapses at the same rate. On the other hand, each actual local clock ....

....whose functional behaviors completely match and whose timings are different within a given bound. They are appropriate and practical to verify distributed objects with temporal uncertainties and real time objects with non strict time constraints. For details of the equivalences please consult [4]. 2.3 Toward Formalizing Asynchronous Real Time Systems We here attempt to formalize the third and fourth combinations. From the temporal viewpoint, asynchronous communication corresponds to a communication where temporal distance between the occurrences of sending and receiving cannot be ....

Satoh, I., and Tokoro, M., A Timed Calculus for Distributed Objects with Clocks, to appear in Proceedings of ECOOP'93, July, 1993.

....to define and compare various real time languages through this semantics framework. Also, the semantics implicitly assumes a global clock, whereas in distributed systems such a global clock cannot inherently be realized. We have already developed a process calculus based on non global clocks in [16]. We plan to investigate a semantics for distributed real time programming languages by using the calculus. Acknowledgements We are grateful to Vasco Vasconcelos (Keio University) for helpful comments on an earlier version of this paper. We would like to thank anonymous referees for providing ....

Satoh, I., and Tokoro, M., A Timed Calculus for Distributed Objects with Clocks, Proceedings of ECOOP'93, LNCS 707, p326-345, Springer-Verlag, 1993.

....the required precision of time information is finer than the intervals of clock synchronizations, differences and uncertainties among clocks may lead cooperations among distributed processes to timing failures. 1 This chapter is a modified version of an article that has been published earlier in [66, 68]. CHAPTER 4. LOCALITY IN TIME 55 We need to analyze the influences of the inaccuracies of clocks upon the behavioral and temporal properties of distributed systems. A number of computing models for distributed systems have already been proposed. However, most of them are essentially formulated ....

I. Satoh and M. Tokoro. A Timed Calculus for Distributed Objects with Clocks. In Proceedings of European Conference on Object Oriented Programming (ECOOP'93), volume 707 of Lecture Notes in Computer Science, pages 326--345. Springer-Verlag, July 1993.

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