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124
P.R.: General distributions in process algebra. In: Lectures on formal methods and performance analysis: first EEF/Euro summer school on trends in computer science
, 2002
"... Abstract. This paper is an informal tutorial on stochastic process algebras, i.e., process calculi where action occurrences may be subject to a delay that is governed by a (mostly continuous) random variable. Whereas most stochastic process algebras consider delays determined by negative exponenti ..."
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Abstract. This paper is an informal tutorial on stochastic process algebras, i.e., process calculi where action occurrences may be subject to a delay that is governed by a (mostly continuous) random variable. Whereas most stochastic process algebras consider delays determined by negative exponential distributions, this tutorial is concerned with the integration of general, nonexponential distributions into a process algebraic setting. We discuss the issue of incorporating such distributions in an interleaving semantics, and present some existing solutions to this problem. In particular, we present a process algebra for the specification of stochastic discreteevent systems modeled as generalized semiMarkov chains (GSMCs). Using this language stochastic discreteevent systems can be described in an abstract and modular way. The operational semantics of this process algebra is given in terms of stochastic automata, a novel mixture of timed automata and GSMCs. We show that GSMCs are a proper subset of stochastic automata, discuss various notions of equivalence, present congruence results, treat equational reasoning, and argue how an expansion law in the process algebra can be obtained. As a case study, we specify the root contention phase within the standardized IEEE 1394 serial bus protocol and study the delay until root contention resolution. An overview of related work on general distributions in process algebra and a discussion of trends and future work complete this tutorial. 1
Probabilistic Models for Reo Connector Circuits
 Reasoning About ChannelBased Component Connectors 15
, 2005
"... Constraint automata have been used as an operational model for Reo which o#ers a channelbased framework to compose complex component connectors. In this paper, we introduce a variant of constraint automata with discrete probabilities and nondeterminism, called probabilistic constraint automata. The ..."
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Constraint automata have been used as an operational model for Reo which o#ers a channelbased framework to compose complex component connectors. In this paper, we introduce a variant of constraint automata with discrete probabilities and nondeterminism, called probabilistic constraint automata. These can serve for compositional reasoning about connector components, modelled by Reo circuits with unreliable channels, e.g., that might loose or corrupt messages, or channels with random output values that, e.g., can be helpful to model randomized coordination principles.
Thread Algebra for Sequential PolyThreading
, 2008
"... Threads as considered in basic thread algebra are primarily looked upon as behaviours exhibited by sequential programs on execution. It is a fact of life that sequential programs are often fragmented. Consequently, fragmented program behaviours are frequently found. In this paper, we consider this ..."
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Threads as considered in basic thread algebra are primarily looked upon as behaviours exhibited by sequential programs on execution. It is a fact of life that sequential programs are often fragmented. Consequently, fragmented program behaviours are frequently found. In this paper, we consider this phenomenon. We extend basic thread algebra with the barest mechanism for sequencing of threads that are taken for fragments. This mechanism, called sequential polythreading, supports both autonomous and nonautonomous thread selection in sequencing. We relate the resulting theory to the algebraic theory of processes known as ACP and use it to describe analytic execution architectures suited for fragmented programs.
The cones and foci proof technique for timed transition systems
 Information Processing Letters
"... ..."
Dynamic Consistency in Process Algebra: From Paradigm to ACP
, 2010
"... The coordination modelling language Paradigm addresses collaboration between components in terms of dynamic constraints. Within a Paradigm model, component dynamics are consistently specified at various levels of abstraction. The operational semantics of Paradigm is given. For a large, general subcl ..."
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Cited by 8 (6 self)
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The coordination modelling language Paradigm addresses collaboration between components in terms of dynamic constraints. Within a Paradigm model, component dynamics are consistently specified at various levels of abstraction. The operational semantics of Paradigm is given. For a large, general subclass of Paradigm models a translation into process algebra is provided. Once expressed in process algebra, relying on a correctness result, Paradigm models are amenable to process algebraic reasoning and to verification via the mCRL2 toolset. Examples of a scheduling problem illustrate the approach.
Distributed strategic interleaving with load balancing. To appear in Future Generation Computer Systems. Preliminary version: Computer Science
"... Abstract. In a previous paper, we developed an algebraic theory of threads, interleaving of threads, and interaction of threads with services. In the current paper, we assume that the threads and services are distributed over the nodes of a network. We extend the theory developed so far to the dist ..."
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Abstract. In a previous paper, we developed an algebraic theory of threads, interleaving of threads, and interaction of threads with services. In the current paper, we assume that the threads and services are distributed over the nodes of a network. We extend the theory developed so far to the distributed case by introducing distributed interleaving strategies that support explicit thread migration and see to load balancing or capability searching by implicit thread migration.
Abstract Integration of Conceptual Process Models by the Example of Eventdriven Process Chains
"... It has become common place in business life that companies with related operations engage in a socalled merger in order to benefit from synergies or from combined products and services. In order to handle the complexity of such an endeavour, it is important to utilise a structured approach for fin ..."
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Cited by 7 (0 self)
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It has become common place in business life that companies with related operations engage in a socalled merger in order to benefit from synergies or from combined products and services. In order to handle the complexity of such an endeavour, it is important to utilise a structured approach for finding similarities and contradictions in business process models of both partners. In this paper, we present a suitable procedure for this task. Furthermore, we demonstrate how to identify those specific activities within the overall business processes which must be adapted. In particular, we discuss how such integration can be conducted if the processes of both parties are modelled with Eventdriven Process Chains, one of the most popular conceptual business process modelling languages. By the help of a running example we illustrate the join operator for the integration of these models and the interpretation of the result. 1
Equational reasoning on ad hoc networks
 In Proceedings of the Third International Conference on Fundamentals of Software Engineering (FSEN
, 2009
"... Abstract. We provide an equational theory for Restricted Broadcast Process Theory to reason about ad hoc networks. We exploit an extended algebra called Computed Network Theory to axiomatize restricted broadcast. It allows one to define an ad hoc network with respect to the underlying topologies. We ..."
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Abstract. We provide an equational theory for Restricted Broadcast Process Theory to reason about ad hoc networks. We exploit an extended algebra called Computed Network Theory to axiomatize restricted broadcast. It allows one to define an ad hoc network with respect to the underlying topologies. We give a sound and complete axiomatization for the recursionfree part of the term algebra CNT, modulo what we call rooted branching computed network bisimilarity. 1
A Probabilistic Branching Bisimulation for Quantum Processes. quantph/0508116, 2005. [Lal06] [LGP06] Marie Lalire. Développement d’une notation alorithmique pour le calcul quantique
, 2006
"... Full formal descriptions of algorithms making use of quantum principles must take into account both quantum and classical computing components and assemble them so that they communicate and cooperate. Moreover, to model concurrent and distributed quantum computations, as well as quantum communicatio ..."
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Full formal descriptions of algorithms making use of quantum principles must take into account both quantum and classical computing components and assemble them so that they communicate and cooperate. Moreover, to model concurrent and distributed quantum computations, as well as quantum communication protocols, quantum to quantum communications which move qubits physically from one place to another must also be taken into account. Inspired by classical process algebras, which provide a framework for modeling cooperating computations, a process algebraic notation is defined, which provides a homogeneous style to formal descriptions of concurrent and distributed computations comprising both quantum and classical parts. Based upon an operational semantics which makes sure that quantum objects, operations and communications operate according to the postulates of quantum mechanics, a probabilistic branching bisimulation is defined among processes considered as having the same behavior. 1
Data anonymity in the FOO voting scheme
 In Proceedings VODCA’06, ENTCS
, 2006
"... We study one of the many aspects of privacy, which is referred to as data anonymity, in a formal context. Data anonymity expresses whether some piece of observed data, such as a vote, can be attributed to a user, in this case a voter. We validate the formal treatment of data anonymity by analyzing a ..."
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We study one of the many aspects of privacy, which is referred to as data anonymity, in a formal context. Data anonymity expresses whether some piece of observed data, such as a vote, can be attributed to a user, in this case a voter. We validate the formal treatment of data anonymity by analyzing a wellknown electronic voting protocol.