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Triggered Message Sequence Charts
, 2006
"... This paper introduces Triggered Message Sequence Charts (TMSCs), a graphical, mathematically wellfounded framework for capturing scenariobased system requirements of distributed systems. Like Message Sequence Charts (MSCs), TMSCs are graphical depictions of scenarios, or exchanges of messages be ..."
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Cited by 40 (2 self)
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This paper introduces Triggered Message Sequence Charts (TMSCs), a graphical, mathematically wellfounded framework for capturing scenariobased system requirements of distributed systems. Like Message Sequence Charts (MSCs), TMSCs are graphical depictions of scenarios, or exchanges of messages between processes in a distributed system. Unlike MSCs, however, TMSCs are equipped with a notion of trigger that permits requirements to be made conditional; a notion of partiality indicating that a scenario may be subsequently extended; and a notion of refinement for assessing whether or not a more detailed specification correctly elaborates on a less detailed one. The TMSC notation also includes a collection of composition operators allowing structure to be introduced into scenario specifications, so that interactions among different scenarios may be studied. In the first part of this paper, TMSCs are introduced, and their use in support of requirements modeling is illustrated via two extended examples. The second part develops the mathematical underpinnings of the language.
A Kleene Theorem and Model Checking Algorithms for Existentially Bounded Communicating Automata
 INFORMATION AND COMPUTATION 204:920–956
, 2006
"... The behavior of a network of communicating automata is called existentially bounded if communication events can be scheduled in such a way that the number of messages in transit is always bounded by a value that depends only on the machine, not the run itself. We show a Kleene theorem for existentia ..."
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Cited by 26 (7 self)
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The behavior of a network of communicating automata is called existentially bounded if communication events can be scheduled in such a way that the number of messages in transit is always bounded by a value that depends only on the machine, not the run itself. We show a Kleene theorem for existentially bounded communicating automata, namely the equivalence between communicating automata, globallycooperative compositional message sequence graphs, and monadic second order logic. Our characterization extends results for universally bounded models, where for each and every possible scheduling of communication events, the number of messages in transit is uniformly bounded [15, 17]. As a consequence, we give solutions in the spirit of [22] for various model checking problems on networks of communicating automata that satisfy our optimistic restriction.
Symbolic Message Sequence Charts
"... Message Sequence Charts (MSCs) are a widely used visual formalism for scenariobased specifications of distributed reactive systems. In its conventional usage, an MSC captures an interaction snippet between concrete objects in the system. This leads to voluminous specifications when the system conta ..."
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Cited by 8 (3 self)
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Message Sequence Charts (MSCs) are a widely used visual formalism for scenariobased specifications of distributed reactive systems. In its conventional usage, an MSC captures an interaction snippet between concrete objects in the system. This leads to voluminous specifications when the system contains several objects that are behaviorally similar. MSCs also play an important role in the modelbased testing of reactive systems, where they may be used for specifying (partial) system behaviors, describing test generation criteria, or representing test cases. However, since the number of processes in a MSC specification are fixed, modelbased testing of systems consisting of process classes may involve a significant amount of rework. For example, reconstructing system models, or regenerating test cases for systems differing only in the number of processes of various types. In this article, we propose a scenario based notation, called Symbolic Message Sequence Charts (SMSCs), for modeling, simulation, and testing of process classes. SMSCs are a lightweight syntactic and semantic extension of MSCs where, unlike MSCs, a SMSC lifeline can denote some/all objects from a collection. Our extensions give us substantially more modeling power. Moreover, we present an abstract execution semantics for (structured collections of) SMSCs. This allows us
Compositional message sequence charts (cmscs) are better to implement than mscs
 In TACAS
, 2005
"... Abstract. Communicating Finite States Machines (CFMs) and Message Sequence Graphs (MSCgraphs for short) are two popular specification formalisms for communicating systems. MSCgraphs capture requirements (scenarios), hence they are the starting point of the design process. Implementing an MSCgr ..."
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Cited by 5 (0 self)
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Abstract. Communicating Finite States Machines (CFMs) and Message Sequence Graphs (MSCgraphs for short) are two popular specification formalisms for communicating systems. MSCgraphs capture requirements (scenarios), hence they are the starting point of the design process. Implementing an MSCgraph means obtaining an equivalent deadlockfree CFM, since CFMs correspond to distributed messagepassing algorithms. Several partial answers for the implementation have been proposed. E.g., localchoice MSCgraphs form a subclass of deadlockfree CFM: Testing equivalence with some localchoice MSCgraph is thus a partial answer to the implementation problem. Using Compositional MSCs, we propose a new algorithm which captures more implementable models than with MSCs. Furthermore, the size of the implementation is reduced by one exponential. 1
A Coalgebraic Semantic Framework for Reasoning about UML Sequence Diagrams
 In Proceedings of QSIC’08. IEEE Computer Society
, 2008
"... If, as a wellknown aphorism states, modelling is for reasoning, this paper is an attempt to define and apply a formal semantics to UML sequence diagrams in order to enable rigourous reasoning about them. Actually, model transformation plays a fundamental role in the process of software development, ..."
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If, as a wellknown aphorism states, modelling is for reasoning, this paper is an attempt to define and apply a formal semantics to UML sequence diagrams in order to enable rigourous reasoning about them. Actually, model transformation plays a fundamental role in the process of software development, in general, and in model driven engineering in particular. Being a de facto standard in this area, UML is no exception, even if the number and diversity of diagrams expressing UML models makes it difficult to base its semantics on a single framework. This paper builds on previous attempts to base UML semantics in a coalgebraic setting and illustrates the application of the proposed framework to reason about composition and refactoring of sequence diagrams. 1.
Quantifying the Discord: Order Discrepancies in Message Sequence Charts
 in "Special Issue of ATVA’07, International Journal of Foundations of Computer Sciecnce (IJFCS)", vol. in press, 2009 FR SG IL IT BG . Activity Report INRIA 2009
"... Abstract. Message Sequence Charts (MSCs) and Highlevel Message Sequence Charts (HMSCs) are formalisms used to describe scenarios of message passing protocols. We propose using Allen’s logic to represent the temporal order of the messages. We introduce the concept of discord to quantify the discrepa ..."
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Abstract. Message Sequence Charts (MSCs) and Highlevel Message Sequence Charts (HMSCs) are formalisms used to describe scenarios of message passing protocols. We propose using Allen’s logic to represent the temporal order of the messages. We introduce the concept of discord to quantify the discrepancies between the intuition and the semantics of the ordering between messages in different nodes of an HMSC. We study its algorithmic properties: we show that while the discord of a pair of messages is hard to compute in general, the problem becomes polynomialtime computable if the number of nodes of the HMSC or the number of processes is constant. Moreover, for a given HMSC, it is always computationally easy to identify a pair of messages that exhibits the worstcase discord and compute the discord of this pair. 1
Modelling
"... www.elsevier.com/locate/tcs In UML 2.0 sequence diagrams have been considerably extended but their expressiveness and semantics remains problematic in several ways. In other work we have shown how sequence diagrams combined with an OCL liveness template gives us a much richer language for interobje ..."
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www.elsevier.com/locate/tcs In UML 2.0 sequence diagrams have been considerably extended but their expressiveness and semantics remains problematic in several ways. In other work we have shown how sequence diagrams combined with an OCL liveness template gives us a much richer language for interobject behaviour specification. In this paper, we give a semantics of these enriched diagrams using labelled event structures. Further, we show how sequence diagrams can be embedded into a trueconcurrent twolevel logic interpreted over labelled event structures. The top level logic, called communication logic, is used to describe interobject specification, whereas the lower level logic, called home logic, describes intraobject behaviour. An interesting consequence of using this logic relates to how statebased behaviour can be synthesised from interobject specifications. Plans of extending the Edinburgh Concurrency Workbench in this context are discussed.