Pierpaolo Degano and Corrado Priami. Causality for mobile processes. In Zoltan Fulop and Ferenc Gecseg, editors, Proceedings of ICALP '95, volume 944 of Lecture Notes in Computer Science, pages 660671. Springer-Verlag, 1995.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....a coloured labelled transition semantics, allowing more direct statements of security properties of wrappers that interact with their environment. The coloured calculus is a trade o it captures less detailed causality information than the noninterleaving models studied in concurrency theory [37, 3, 7] but is much simpler; it captures enough information to express interesting security properties. In [28] we also expressed a number of other desirable properties of wrappers that they honestly forward messages between component and environment, and that they mediate all communication between ....

Pierpaolo Degano and Corrado Priami. Causality for mobile processes. In Zoltan Fulop and Ferenc Gecseg, editors, Proceedings of ICALP '95, volume 944 of Lecture Notes in Computer Science, pages 660-671. Springer-Verlag, 1995.

....labelled transition semantics, allowing more direct statements of security properties of wrappers that interact with their environment. The coloured calculus is a trade o it captures less detailed causality information than the non interleaving models studied in concurrency theory [WN95, BS95, DP95] but is much simpler; it captures enough information to express interesting security properties. In [SV99a] we also expressed a number of other desirable properties of wrappers that they honestly forward messages between component and environment, and that they mediate all communication ....

Pierpaolo Degano and Corrado Priami. Causality for mobile processes. In Zoltan Fulop and Ferenc Gecseg, editors, Proceedings of ICALP '95, volume 944 of Lecture Notes in Computer Science, pages 660-671. Springer-Verlag, 1995.

....labelled transition semantics, allowing more direct statements of security properties of wrappers that interact with their environment. The coloured calculus is a trade off it captures less detailed causality information than the non interleaving models studied in concurrency theory [WN95, BS95, DP95] but is much simpler; it captures enough information to express interesting security properties. In [SV99a] we also expressed a number of other desirable properties of wrappers that they honestly forward messages between component and environment, and that they mediate all communication between ....

Pierpaolo Degano and Corrado Priami. Causality for mobile processes. In Zoltan Fulop and Ferenc Gecseg, editors, Proceedings of ICALP '95, volume 944 of Lecture Notes in Computer Science, pages 660671. Springer-Verlag, 1995.

....a coloured labelled transition semantics, allowing more direct statements of security properties of wrappers that interact with their environment. The coloured calculus is a tradeo it captures less detailed causality information than the non interleaving models studied in concurrency theory [44, 6, 11] but is much simpler; it captures enough information to express interesting security properties. In [35] we also expressed a number of other desirable properties of wrappers that they honestly forward messages between component and environment, and that they mediate all communication between ....

Pierpaolo Degano and Corrado Priami. Causality for mobile processes. In Zoltan Fulop and Ferenc Gecseg, editors, Proceedings of ICALP '95, volume 944 of Lecture Notes in Computer Science, pages 660-671. Springer-Verlag, 1995.

....is based on traditional CCS [24] in particular, we reduce concurrency to nondeterminism using interleaving. Other semantic theories of concurrency [38] treat parallelism as a primitive notion; such truly concurrent frameworks include causal approaches e.g. partial order semantics [12,13,37], event structures [30] proved transitions [4] and Mazurkiewicz traces [23] and location semantics [5,15,26,27] As these theories make concurrency explicit, they may be seen as natural bases for modeling distributed systems. However, in making concurrency generally observable, the ....

....respect to the operators included in the considered algebra. Thus, it is difficult to compare priority approaches of both areas, Petri 27 Nets and process algebras, from a semantic point of view. Finally, priorities can implicitly arise when studying causality for mobile processes (see e.g. [13]) In these approaches priorities cut off superfluous paths that only present new temporal but not causal dependencies of systems. Hence, this kind of priorities is equipped with a global nature of pre emption. In contrast, the local view of pre emption in CCS prio is used for restricting the ....

P. Degano and C. Priami. Causality of mobile processes. In Z. Fulop and F. G'ecseg, editors, International Conference on Automata, Languages and Programming (ICALP '95), volume 944 of Lecture Notes in Computer Science, pages 660--671, Szeged, Hungary, July 1995. Springer-Verlag.

.... which is suited for our aims, hence providing calculus with a multistep semantics (new to the best of our knowledge) Finally, we present a causal semantics for P T nets with inhibitor arcs; the induced causal semantics for calculus is compared with those recently appeared in the literature [2, 6]. 1.1 Related Work Net Semantics The only paper we know dealing with a net semantics is [7] There Engelfriet considers the small calculus (no alternative composition) for which he studies the reduction semantics (communications only) Because of these limited aims, the semantics is greatly ....

....Consider the two processes p = y) xy:0 j yz:0) and q = y) xy: yz:0) These processes are not causal bisimilar according to [2] there is a link dependency in the former agent) whereas they are causal bisimilar for us. Our approach to causality is also different from the one given in [6]. First of all, they follow the so called read write causality, according to which outputs can pass their causes to inputs but not viceversa (i.e. the cause crossing in communication is not symmetric but directioned from outputs to inputs) The symmetric causes missing in communication are ....

[Article contains additional citation context not shown here]

P. Degano, C. Priami, "Causality for Mobile Processes", to appear in Proc. ICALP'95, LNCS, Springer, 1995.

....of specifications of concurrent systems closer and closer to implementations. In this way, it is possible to analyse both qualitative and quantitative aspects of systems on tightly related formal descriptions [11] More precisely, we exploit proved transition systems, a parametric model used in [9, 10] to describe uniformly different qualitative aspects of processes. The transitions of these transition systems are labelled by encodings of their proofs. Then, by inspecting these richer labels we rebuild the operations needed for deducing actions and we can derive their context sensitive costs, ....

....information, in the style of [8, 6, 9] Essentially, the label of a transition records the inference rules used during its deduction, besides the action itself. It is then possible to derive different semantic models for the calculus by extracting new kinds of labels from the enriched ones. In [10] the first and the last authors studied non interleaving qualitative aspects of the calculus. In the next sections we apply similar techniques to derive a machinedependent temporal model. Processes are given a non interleaving semantics, so it is possible to single out the sequential components ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....by encodings of their deduction trees. The rich labels allow us to easily derive an enabling relation from the transitions of a computation (i.e. a sequence of transitions) simply by looking at transitions [33] This relation is the complement of the concurrency relation over a computation [16]. Then, we use this truly concurrent information to compute the firing distributions of concurrent transitions. Roughly speaking, the distribution of a transition must be influenced by the one of all the transitions fired from states where it was enabled. Note that the influencing transitions ....

.... (x) R j S) j R j (x)S if x 62 fn(R) and (x)P j P if x 62 fn(P ) 44 Corrado Priami Note that and j are neither associative nor commutative to avoid multitransition systems as in [23] However, commutativity and associativity of and j are easily recovered to carry out behavioural analysis [16] by dropping tags i and jj i from labels, thus yielding the classical interleaving semantics. We call a variant of P ;F Gamma Q, a transition which only differs in that P and Q have been replaced by structurally congruent processes, and has been ff converted, where a name bound in ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....or being concerned with the development of program equivalences. So far the approach to semantics for Facile has been based on the interleaving approach to modeling concurrency. In this paper we present a non interleaving semantics for Facile, based on the parametric approach introduced in [6, 7]. We adopt a very concrete (SOS) transition system whose transitions are labelled by encodings of their proofs. We then instantiate it to non interleaving semantics through relabelling functions, which maintain only the relevant information in the labels. This approach allows us to use the ....

....value 0 is assigned to n for spawn(be) since be is activated on the same node as the spawn operation itself. The integer i denotes the number of jjj operators between the node n and the node performing the r spawn, i.e. i is the relative address of the two nodes. Following the developments in [6, 7], we extend actions with the parallel structure of the process which executes them. Definition 3.2 (proof terms) Let 2 Act, oe 2 fjjj 0 ; jjj 1 g , and # 2 fjj 0 ; jj 1 g . The set Theta of proof terms is: foe# g [ foe#hoe 0 # 0 ; oe 1 # 1 i : 2 Commg [ foe 0 # 0 ffloe 1 # 1 g ....

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....of its deduction. These kinds of transition systems are called proved [2] In particular, labels record the parallel structure of processes and permit to derive the relations of interest by looking at computations. This technique has been developed for CCS in [8] and for mobile processes in [9]. The advantage of enriching labels only is that the resulting transition system is finite state whenever the classical interleaving one is such. This is not true when configurations are modified. Consider the process rec x ff:x whose standard transition system is made up of a single node and a ....

....with standard configurations (unlike the one in [7] in spite of their interleaving nature. We modify the causal (mo) semantics of CCS presented in [8] to obtain a partial ordering semantics. Note that the same can be done for calculus [12] by modifying the causal semantics presented in [9], accordingly. We start with the proved transition system. Following [8] a dependency relation between transitions allows us to relabel proved computations to yield the causal semantics. We simply modify the relabelling function to obtain a po semantics, leaving unchanged the definition of ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....this extension in the framework of mobile computing [3] The rich labelling of transitions is the means to obtain different views of the same system. Indeed, it is possible to retrieve many semantic models presented in the literature (interleaving, causal, local) by simply relabelling transitions [2]. The relabelling functions serve also as a basis to compare on firm grounds different models: we only need to compare the corresponding relabellings. A fringe benefit is that all these models are compatible to one another by construction. Proved transition systems can originate a hierarchy of ....

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....[10] The definition of the operational semantics follows the SOS style [15] where the activities of a system are represented by transitions deduced according to a set of inference rules driven by the syntax. More precisely, we exploit proved transition systems, a parametric model used in [8, 9] to uniformly describe different qualitative aspects of processes. Transitions are labelled by encodings of their proofs. Intuitively, the proof of a transition can be interpreted as the low level routines performed by the run time support to execute the transition. Then, by inspecting these rich ....

....our enhanced labels, in the style of [7, 4, 8] Essentially, the label of a transition records the inference rules used during its deduction, besides the action itself. It is then possible to derive different semantic models for HO by extracting new kinds of labels from the enriched ones. In [9] the last two authors studied qualitative aspects of the calculus. In addition, we extract the encoding of the proof from an enhanced label and we call it proof term. Finally, we introduce a function that takes an enhanced label to the corresponding standard action label. Definition 2.2 Let L = ....

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....or being concerned with the development of program equivalences. So far the approach to semantics for Facile has been based on the interleaving approach to modeling concurrency. In this paper we present a non interleaving semantics for Facile, based on the parametric approach introduced in [12, 13]. We adopt a very concrete (SOS) transition system whose transitions are labelled by encodings of their proofs. We then instantiate it to causal semantics through relabelling functions, which maintain only the relevant information in the labels. This approach allows us to use the standard ....

....The value 0 is assigned to n for spawn(be) since be is activated on the same node as the spawn operation itself. The integer i denotes the number of jjj operators between the node n and the node performing the r spawn, i.e. i is the relative address of the two nodes. Following the developments in [12, 13], we extend actions with the parallel structure of the process which executes them. Definition 3.2 (proof terms) Let 2 Act, oe 2 fjjj 0 ; jjj 1 g , and # 2 fjj 0 ; jj 1 g . The set Theta of proof terms is: foe# g [ foe#hoe 0 # 0 ; oe 1 # 1 i : 2 Commg [ foe 0 # 0 ffloe 1 # 1 g ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....suffices thinking of Internet to see that this assumption is irrealistic. In this paper we do not assume a completely interconnected network, but we merge topology information with semantic descriptions of systems. The main tool we use to carry out this programme is the proved transition system [4, 8, 9]. The semantics of S is given in SOS style [18] Systems are represented by graphs (transition systems) whose nodes are terms of the language (processes) and whose arcs (transitions) represent the activities which make states change. Transitions are labelled by (portion of) encodings of their ....

.... is r 0 =r a (P ) Theta r 1 =r a (Q) Therefore the rate of synchronizations is R(P; a; Q; a; r 0 ; r 1 ) 1) r 0 =r a (P ) Theta r 1 =r a (Q) Theta min(r a (P ) r a (Q) The early operational semantics of S is defined in SOS style and the labels of transitions (proof terms) [8, 9] contains encodings of (portions of) their deduction trees. Definition 2.2 (Proof terms) Let # 2 fjj 0 ; jj 1 ; 0 ; 1 g . Proof terms (with metavariable ) are defined as : #( r) j (#hjj 0 # 0 0 ; jj 1 # 1 1 i; r) with 0 = x(z) iff 1 is x(y) xy) or vice versa. Function ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....semantics for Facile was presented in [4] That semantics covered the functional concurrent core of Facile. In this paper we further develop the non interleaving semantics for Facile to capture the distributed aspects of Facile. The semantics is based on the parametric approach introduced in [7, 8]. We adopt a very concrete (SOS) transition system whose transitions are labelled by encodings of their proofs. We then instantiate it to locality semantics through relabelling functions, which maintain only the relevant information in the labels. This approach allows us to use the standard ....

....The value 0 is assigned to n for spawn(be) since be is activated on the same node as the spawn operation itself. The integer i denotes the number of jjj operators between the node n and the node performing the r spawn, i.e. i is the relative address of the two nodes. Following the developments in [7, 8], we extend actions with the parallel structure of the process which executes them. Definition4. Let 2 Act, oe 2 fjjj 0 ; jjj 1 g , and # 2 fjj 0 ; jj 1 g . The set Theta of proof terms is: foe# g [ foe#hoe 0 # 0 ; oe 1 # 1 i : 2 Commg [ foe 0 # 0 ffloe 1 # 1 g Elements of Theta ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....of a process a continuous time Markov chain that is used to obtain performance measures with standard numerical techniques. Since we are interested here in mobile computing, we adopt the stochastic extension of calculus [29] We begin with a proved version of the SOS semantics of calculus [7]. Representations of processes are transition systems whose transitions are labelled by (portion of) encodings of their deduction trees. The new labels are called proof terms. For instance, the a transition of process (a j b) c is labelled 0 jj 0 a. The intuitive meaning of tag 0 (jj 0 ) is ....

.... communication is r 0 =r a (P ) Theta r 1 =r a (Q) Therefore the rate of synchronizations is R(P; a; Q; a; r 0 ; r 1 ) r 0 =r a (P ) Theta r 1 =r a (Q) Theta min(r a (P ) r a (Q) 1) The early operational semantics of S is defined in SOS style and the labels of transitions (proof terms) [6, 7] contains encodings of (portions of) their deduction trees. The additional information is used to keep distinct two transitions with the same label between the same pair of configurations. Actually, we want to distinguish processes (a; r) a; r) and (a; r) from a performance point of view: the ....

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....So far the approach to semantics for Facile has been based on the interleaving approach to modeling concurrency. In this paper we present a non interleaving semantics for Facile. The presentation of this non interleaving semantics for Facile is based on the parametric approach introduced in [7, 8]. We adopt a very concrete (SOS) transition system whose transitions are labelled by encodings of their proofs. We then instantiate it to non interleaving semantics through relabelling functions, which maintain only the relevant information in the labels. This approach allows us to use the ....

....will sometimes be referred to as Comm. Elements of Act are denoted as ; i ; 0 ; The label ( k) is caused by channel(t) and contains the name of the new channel. The label Phi(be) represents the creation of a new process to be activated by spawn(be) Following the developments in [7, 8], we extend actions with the parallel structure of the process which executes them. Definition 3.2 (proof terms) Let 2 Act, and # 2 fjj 0 ; jj 1 g . The set Theta of proof terms is: f# g [ f#h# 0 ; # 1 i : 2 Commg Elements of Theta are denoted as ; i ; 0 ; Function : ....

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....So far the approach to semantics for Facile has been based on the interleaving approach to modeling concurrency. In this paper we present a non interleaving semantics for Facile. The presentation of this non interleaving semantics for Facile is based on the parametric approach introduced in [6, 7]. We adopt a very concrete (SOS) transition system whose transitions are labelled by encodings of their proofs. We then instantiate it to non interleaving semantics through relabelling functions, which maintain only the relevant information in the labels. This approach allows us to use the ....

....will sometimes be referred to as Comm. Elements of Act are denoted as ; i ; 0 ; The label ( k) is caused by channel(t) and contains the name of the new channel. The label Phi(be) represents the creation of a new process to be activated by spawn(be) Following the developments in [6, 7], we extend actions with the parallel structure of the process which executes them. Definition2. Let 2 Act, and # 2 fjj 0 ; jj 1 g . The set Theta of proof terms is: f# g [ f#h# 0 ; # 1 i : 2 Commg Elements of Theta are denoted as ; i ; 0 ; Function : Theta Act ....

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....# 0 the path from P to G. Consider Fig. 1, and let G be P 3 and R be P 1 . The address of P 3 relative to P 1 is jj 0 jj 1 ffljj 1 jj 1 jj 0 . We will inductively build relative addresses while deducing transitions according to the inference rules of the proved transition system of calculus [5]. It suffices to record the application of inference rules involving the j in the label of a deduced transition. Slightly more complex is when a process receives a name and sends it to another process. The name must arrive to the new receiver with the address of the generator (not of the sender) ....

....of x, y and y i . In particular, can be either r(x) or rs or . The standard notions on actions (still ranged over by ) and on names (subject, object, free, bound) as well as the structural congruence on processes, are extended to the new syntax in the obvious way. Following the ideas of [4, 5], we encode in the labels of transitions the parallel structure of processes to identify the sequential component that fires the action. Actually, these labels encode a portion of the proof of the transitions, so we call them proof terms as in [5] Definition9. Labels of transitions (with ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....of projections su ce. We implement the motto TRANSITIONS AS PROOFS through proved transition systems [32, 10] Their transitions are labelled by encodings of their proofs. Then, suitable relabellings yield the wanted models, that are related to each other by comparing their relabelling functions [33, 34, 73, 9]. Also, proved transition systems can originate a hierarchy of semantic descriptions of the same process that are closer and closer to actual implementations. The parallel structure of processes, i.e. the network topology, made explicit by in the proofs of transitions, is exploited in [8] for ....

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660-671. Springer-Verlag, 1995.

....rules out nondeterminism from stochastic process algebras so that performance and reliability analysis can be carried out. All activities enabled attempt to proceed, but only the fastest (the first which ends its delay) succeeds. We begin with a proved version of the SOS semantics of calculus [9]. Representations of processes are transition systems whose transitions are labelled by (portion of) encodings of their deduction trees. The new labels are called proof terms. For instance, the a transition of process (a j b) c is labelled 0 jj 0 a. The intuitive meaning of tag 0 (jj 0 ) is ....

....a transition becomes enabled, it restarts its elapsing time as it would the first time that it is enabled. 2. 2 Operational semantics The early operational semantics of the stochastic calculus (S ) is defined in SOS style by enriching the labels of transitions with encodings of their proofs [8, 9] and with probabilistic distributions. The additional information is used to keep distinct two transitions with the same label between the same pair of configurations. Actually, we want to distinguish processes (a; r) a; r) and (a; r) from a performance point of view: the former process is two ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....# 0 the path from P to G. Consider Fig. 1, and let G be P 3 and R be P 1 . The address of P 3 relative to P 1 is jj 0 jj 1 ffljj 1 jj 1 jj 0 . We will inductively build relative addresses while deducing transitions according to the inference rules of the proved transition system of calculus [5]. It suffices to record the application of inference rules involving the j in the label of a deduced transition. Slightly more complex is when a process receives a name and sends it to another process. The name must arrive to the new receiver with the address of the generator (not of the sender) ....

....of x, y and y i . In particular, can be either r(x) or rs or . The standard notions on actions (still ranged over by ) and on names (subject, object, free, bound) as well as the structural congruence on processes, are extended to the new syntax in the obvious way. Following the ideas of [4, 5], we encode in the labels of transitions the parallel structure of processes to identify the sequential component that acts. Actually, these labels encode a portion of the proof of the transitions, so we call them proof terms as in [5] Definition9. Labels of transitions (with metavariable ) ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

....that allows us to derive the class of semantics mentioned above. We consider the proved transition system [6, 2] whose transitions are labelled by encodings of their proofs. The rich labelling of transitions permits us to retrieve the main semantic models presented in the literature as shown in [8, 9]. These models are obtained from the proved one simply by relabelling the transitions in order to drop unwanted details for the problem at hand. The intrinsic structure of transition systems records the temporal ordering in which transitions are fired. In fact, a computation (i.e. a path in the ....

....depends on (one of the) a, yielding a po. We show here that a po description of distributed systems is possible also by transition systems, in spite of their interleaving nature. We introduce relabelling functions of the proved transition system that yield po semantics, unlike the ones defined in [8, 9] which originate mo semantics. Furthermore, we show that po semantics can be retrieved from the mo one through a simple relabelling function. Finally, the classical interleaving description of systems can be obtained in straightforward way from the po semantics (and hence from the mo and proved ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Causality for mobile processes. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995.

No context found.

Pierpaolo Degano and Corrado Priami. Causality for mobile processes. In Zoltan Fulop and Ferenc Gecseg, editors, Proceedings of ICALP '95, volume 944 of Lecture Notes in Computer Science, pages 660671. Springer-Verlag, 1995.

No context found.

P. Degano and C. Priami. Causality for mobile processes. In Z. Fulop and F. Gecseg, editors, Proceedings of ICALP '95, volume 944 of Lecture Notes in Computer Science, pages 660-671. Springer-Verlag, 1995.

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