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The meaning of negative premises in transition system specifications II
 THE JOURNAL OF LOGIC AND ALGEBRAIC PROGRAMMING
, 2004
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Process algebra with timing: real time and discrete time
 Smolka (Eds.), Handbook of Process Algebra
, 2001
"... We present real time and discrete time versions of ACP with absolute timing and relative timing. The startingpoint isanewrealtimeversion with absolute timing, called ACPsat, featuring urgent actions and a delay operator. The discrete time versions are conservative extensions of the discrete time ve ..."
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Cited by 28 (10 self)
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We present real time and discrete time versions of ACP with absolute timing and relative timing. The startingpoint isanewrealtimeversion with absolute timing, called ACPsat, featuring urgent actions and a delay operator. The discrete time versions are conservative extensions of the discrete time versions of ACP being known as ACP dat and ACP drt. The principal version is an extension of ACP sat with integration and initial abstraction to allow for choices over an interval of time and relative timing to be expressed. Its main virtue is that it generalizes ACP without timing and most other versions of ACP with timing in a smooth and natural way. This is shown for the real time version with relative timing and the discrete time version with absolute timing.
Equivalences on Observable Processes
 In Proceedings of the 7th Annual IEEE Symposium on Logic in Computer Science
, 1992
"... The aim of this paper is to nd the nest `observable ' and `implementable' equivalence on concurrent processes. This is a part of a larger programme to develop a theory of observable processes where semantics of processes are based on locally and nitely observable process behaviour, and ..."
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Cited by 21 (6 self)
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The aim of this paper is to nd the nest `observable ' and `implementable' equivalence on concurrent processes. This is a part of a larger programme to develop a theory of observable processes where semantics of processes are based on locally and nitely observable process behaviour, and all process constructs are allowed, provided their operational meaning is de ned by realistically implementable transition rules.
Algebraic Theory of Probabilistic and Nondeterministic Processes
 PROCEEDINGS OF THE WORKSHOP
, 2001
"... In this paper we present an algebraic language for the specification of probabilistic and nondeterministic processes, PNAL, which is a probabilistic extension of EPL (Algebraic Theory of Processes, M. Hennessy) that maintains nondeterminism.We have ..."
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Cited by 14 (0 self)
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In this paper we present an algebraic language for the specification of probabilistic and nondeterministic processes, PNAL, which is a probabilistic extension of EPL (Algebraic Theory of Processes, M. Hennessy) that maintains nondeterminism.We have
An Embedding of ConGolog in 3APL
 IN PROCEEDINGS OF THE 14TH EUROPEAN CONFERENCE ON ARTIFICIAL INTELLIGENCE
, 2000
"... Several highlevel programming languages for programming agents and robots have been proposed in recent years. Each of these languages has its own features and merits. It is still difficult, however, to compare different programming frameworks and evaluate the relative benefits and disadvantages ..."
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Cited by 12 (5 self)
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Several highlevel programming languages for programming agents and robots have been proposed in recent years. Each of these languages has its own features and merits. It is still difficult, however, to compare different programming frameworks and evaluate the relative benefits and disadvantages of these frameworks. In this paper, we present a general method for comparing agent programming frameworks based on a notion of bisimulation, and use it to formally compare the languages ConGolog and 3APL. ConGolog is a concurrent language for highlevel robot programming based on the situation calculus. ConGolog provides a logical perspective on robot programming, but also incorporates a number of imperative programming constructs like sequential composition. 3APL is an agent programming language and its semantics offers a more operational perspective on agents. The language is a combination of logic and imperative programming and provides operators for beliefs, goals and plans of an ag...
Event Notification in Datadriven Coordination Languages: Comparing the Ordered and Unordered Interpretations
, 2000
"... JavaSpaces and TSpaces are two coordination middlewares for distributed Java programming recently proposed by Sun and IBM, respectively. They extend the datadriven coordination model of Linda with an event notification mechanism: a process can register interest in the incoming arrivals of a particu ..."
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Cited by 10 (3 self)
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JavaSpaces and TSpaces are two coordination middlewares for distributed Java programming recently proposed by Sun and IBM, respectively. They extend the datadriven coordination model of Linda with an event notification mechanism: a process can register interest in the incoming arrivals of a particular kind of data and receive communication of the occurrences of these events. In [2, 3] we introduce a process calculus L, based on the Linda coordination model, and we prove that if processes are synchronous with the dataspace (ordered interpretation) L is Turing powerful, while this is not the case if they are asynchronous (unordered interpretation). Here, we introduce a new calculus Ln , obtained by extending L with the event noti cation mechanism, and we prove two main results contrasting with what has been shown for L: (i) Ln is Turing powerful also under the unordered interpretation and (ii) it allows a faithful encoding of the ordered semantics on top of the unordered one.
Discrete Time GenerativeReactive Probabilistic Processes with Different Advancing Speeds
 Theor. Comput. Sci
"... We present a process algebra expressing probabilistic external/internal choices, multiway synchronizations, and processes with dierent advancing speeds in the context of discrete time, i.e. where time is not continuous but is represented by a sequence of discrete steps as in Discrete Time Markov Ch ..."
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Cited by 9 (3 self)
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We present a process algebra expressing probabilistic external/internal choices, multiway synchronizations, and processes with dierent advancing speeds in the context of discrete time, i.e. where time is not continuous but is represented by a sequence of discrete steps as in Discrete Time Markov Chains (DTMCs). To this end, we introduce a variant of CSP that employs a probabilistic asynchronous parallel operator whose synchronization mechanism is based on a mixture of the classical generative and reactive models of probability. In particular, dierently from existing discrete time process algebras, where parallel processes are executed in synchronous locksteps, the parallel operator that we adopt allows processes with dierent probabilistic advancing speeds (mean number of actions executed per time unit) to be modeled. Moreover, our generativereactive synchronization mechanism makes it possible to always derive DTMCs in the case of fully specied systems. We then present a sound and complete axiomatization of probabilistic bisimulation over  nite processes of our calculus, that is a smooth extension of the axiom system for a standard process algebra, thus solving the open problem of cleanly axiomatizing action restriction in the generative model. As a further result, we show that, when evaluating steady state based performance measures which are expressible by attaching rewards to actions, our approach provides an exact solution even if the advancing speeds are considered not to be probabilistic, without incurring the state space explosion problem that arises with standard synchronous approaches. We  nally present a case study on multipath routing showing the expressiveness of our calculus and that it makes it particularly easy to produce scalable specications....
Precongruence Formats for Decorated Trace Preorders
 In Proceedings, 15th IEEE Symposium on Logic in Computer Science. IEEE
, 2000
"... This paper explores the connection between semantic equivalences and preorders for concrete sequential processes, represented by means of labelled transition systems, and formats of transition system specications using Plotkin's structural approach. For several preorders in the linear time { br ..."
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Cited by 4 (2 self)
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This paper explores the connection between semantic equivalences and preorders for concrete sequential processes, represented by means of labelled transition systems, and formats of transition system specications using Plotkin's structural approach. For several preorders in the linear time { branching time spectrum a format is given, as general as possible, such that this preorder is a precongruence for all operators speci able in that format. The formats are derived using the modal characterizations of the corresponding preorders. 1. Introduction Structural operational semantics [24] provides process algebras and specication languages with an interpretation. It generates a (labelled) transition system in which states are the closed terms over a (singlesorted, rstorder) signature, and transitions between states may be supplied with labels. The transition relation is obtained from a transition system specication (TSS), this being a set of proof rules called transition rules. I...
Ordered SOS Process Languages for Branching and Eager Bisimulations
 INFORMATION AND COMPUTATION
, 2002
"... We present a general and uniform method for defining structural operational semantics (SOS) of process operators by traditional Plotkinstyle transition rules equipped with orderings. This new feature allows one to control the order of application of rules when deriving transitions of process terms. ..."
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Cited by 4 (0 self)
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We present a general and uniform method for defining structural operational semantics (SOS) of process operators by traditional Plotkinstyle transition rules equipped with orderings. This new feature allows one to control the order of application of rules when deriving transitions of process terms. Our method is powerful enough to deal with rules with negative premises and copying. We show that rules with orderings, called ordered SOS rules, have the same expressive power as GSOS rules. We identify several classes of process languages with operators defined by rules with and without orderings in the setting with silent actions and divergence. We prove that branching bisimulation and eager bisimulation relations are preserved by all operators in process languages in the relevant classes.