Results 1  10
of
21
Highlevel Message Sequence Charts
, 1997
"... syntax of HMSC A hierarchical graph is a mathematical structure that represents the information contents of an HMSC. The set HGid represents the set of all HMSC names. Obviously, this includes the names of BMSCs. Since we did not provide a formal graphical syntax for HMSC we cannot provide a forma ..."
Abstract

Cited by 49 (4 self)
 Add to MetaCart
syntax of HMSC A hierarchical graph is a mathematical structure that represents the information contents of an HMSC. The set HGid represents the set of all HMSC names. Obviously, this includes the names of BMSCs. Since we did not provide a formal graphical syntax for HMSC we cannot provide a formal mapping from HMSC to hierarchical graphs. However, the intuition is clear. A node in an HMSC contains a reference to another HMSC via its name. Definition 3.3.1 (Hierarchical graphs) A hierarchical graph is either a BMSC or a tuple #id, Nodes, Starts, Ends, Edges, l#, where . id # HGid is the name of the hierarchical graph; . Nodes, Starts, and Ends are pairwise disjoint sets of HMSC reference nodes, start nodes and end nodes respectively with Starts #= ?; . Edges # (Nodes # Starts) × (Nodes # Ends) is a set of edges. An edge (n, n # ) is denoted by n # n # ; . l : Nodes # HGid is a labeling function which associates to a node a reference to an HMSC by means of a...
Interpreting Message Flow Graphs
 Formal Aspects of Computing
, 1995
"... We give a semantics for Message Flow Graphs(MFGs), which play the role for interprocess communication that Program Dependence Graphs play for control ow in parallel processes. MFGs have been used to analyse parallel code, and are closely related to Message Sequence Charts and Time Sequence Diagrams ..."
Abstract

Cited by 48 (9 self)
 Add to MetaCart
We give a semantics for Message Flow Graphs(MFGs), which play the role for interprocess communication that Program Dependence Graphs play for control ow in parallel processes. MFGs have been used to analyse parallel code, and are closely related to Message Sequence Charts and Time Sequence Diagrams in telecommunications systems. Our requirements are rstly, to determine unambiguously exactly what execution traces are speci ed by anMFG, and secondly, to use a nitestate interpretation. Our methods function for both asynchronous and synchronous communications. From a set of MFGs, we de ne a transition system of global states, and from that a Buchi automaton by considering safety and liveness properties of the system. In order easily to describe liveness properties, we interpret the traces of the transition system as a model of MannaPnueli temporal logic. Finally,we describe the expressive power of MFGs by mimicking an arbitrary Buchi automaton by means of a set of MFGs. 1.
Operational Semantics for MSC'96
 Computer Networks and ISDN Systems
, 1998
"... Introduction Recently, the ITU 1 standardised specification language Message Sequence Chart (MSC) [IT96] has been extended with constructs for more complete and structured specifications. The new version of the language is called MSC'96. Currently, research is performed on the extension of the o ..."
Abstract

Cited by 9 (0 self)
 Add to MetaCart
Introduction Recently, the ITU 1 standardised specification language Message Sequence Chart (MSC) [IT96] has been extended with constructs for more complete and structured specifications. The new version of the language is called MSC'96. Currently, research is performed on the extension of the old formal semantics towards a semantics for MSC'96. Ideally, the development of a language and its semantics should go hand in hand. There is little use in defining a fancy syntactic construction without a precise understanding of its meaning. As was the case for the old version of the MSC language, first the syntax and an incomplete and informal semantics were developed, while the construction of a formal semantics was deferred until after the acceptance of the language by the ITU bodies. It is obvious that the aposteriori construction of a formal semantics will reveal many places in which the informal language description is ambiguous, underspecified, inconsistent
Rule formats for determinism and idempotence
 In Proceedings of the 3rd International Conference on Fundamentals of Software Engineering (FSEN’09), Lecture Notes in Computer Science, Kish Island
, 2009
"... Abstract. Determinism is a semantic property of (a fragment of) a language that specifies that a program cannot evolve operationally in several different ways. Idempotency is a property of binary composition operators requiring that the composition of two identical specifications or programs will re ..."
Abstract

Cited by 9 (7 self)
 Add to MetaCart
Abstract. Determinism is a semantic property of (a fragment of) a language that specifies that a program cannot evolve operationally in several different ways. Idempotency is a property of binary composition operators requiring that the composition of two identical specifications or programs will result in a piece of specification or program that is equivalent to the original components. In this paper, we propose two (related) metatheorems for guaranteeing determinism and idempotency of binary operators. These metatheorems are formulated in terms of syntactic templates for operational semantics, called rule formats. We show the applicability of our formats by applying them to various operational semantics from the literature. 1
An Execution Semantics for MSC2000
 In Proc. of the 10th International SDL Forum
, 2001
"... Message Sequence Charts (MSCs) is a visual notation for expressing requirements on communicating systems. Their expressive power has traditionally been somewhat limited, and additional information is usually needed by tools that manipulate them, e.g., to derive test suites. The new standard MSC ..."
Abstract

Cited by 7 (0 self)
 Add to MetaCart
Message Sequence Charts (MSCs) is a visual notation for expressing requirements on communicating systems. Their expressive power has traditionally been somewhat limited, and additional information is usually needed by tools that manipulate them, e.g., to derive test suites. The new standard MSC2000, developed by ITUT, extends earlier versions by constructs for data and highlevel control, so that it may be possible to derive test sequences directly from MSC requirements, without need of additional information. Motivated by this, we present an execution semantics for a signicant part of the MSC2000 standard.
Realizability criteria for compositional MSC
 In 11th Intl. Conf. on Algebraic Methodology and Software Technology (AMAST’06), volume 4019 of LNCS
, 2006
"... Abstract. Synthesizing proper implementations for scenariobased specifications is often impossible, due to the distributed nature of implementations. To be able to detect problematic specifications, realizability criteria have been identified, such as nonlocal choice. In this work we develop a for ..."
Abstract

Cited by 7 (0 self)
 Add to MetaCart
Abstract. Synthesizing proper implementations for scenariobased specifications is often impossible, due to the distributed nature of implementations. To be able to detect problematic specifications, realizability criteria have been identified, such as nonlocal choice. In this work we develop a formal framework to study realizability of compositional MSC [GMP03]. We use it to derive a complete classification of criteria that is closely related to the criteria for MSC from [MGR05]. Comparing specifications and implementations is usually complicated, because different formalisms are used. We treat both of them in terms of a single formalism. Thereto we extend the partial order semantics of [Pra86,KL98] with a way to model deadlocks and with a more sophisticated way to address communication. 1
Fischer's Protocol in Timed Process Algebra
, 1994
"... Timed algebraic process theories can be developed with quite different purposes in mind. One can aim for theoretical results about the theory itself (completeness, expressiveness, decidability), or one can aim for practical applicability to nontrivial protocols. Unfortunately, these aims do not go ..."
Abstract

Cited by 7 (2 self)
 Add to MetaCart
Timed algebraic process theories can be developed with quite different purposes in mind. One can aim for theoretical results about the theory itself (completeness, expressiveness, decidability), or one can aim for practical applicability to nontrivial protocols. Unfortunately, these aims do not go well together. In this paper we take two theories, which are probably of the first kind, and try to find out how well suited they are for practical verifications. We verify Fischer's protocol for mutual exclusion in the settings of discretetime process algebra (ACP dt ) and realtime process algebra (ACP ur ). We do this by transforming the recursive specification into an equivalent linear specification, and then dividing out the maximal bisimulation relation. The required mutual exclusion result can then be found by reasoning about the obtained process graph. Finally, we consider the ease of the verification, and ways to adapt the theory to make it more practical. It will turn out that the...
Nonlocal choice and beyond: Intricacies of MSC choice nodes
 In Fundamental Approaches
, 2005
"... Abstract. MSC is a visual formalism for specifying the behavior of systems. To obtain implementations for individual processes, the MSC choice construction poses fundamental problems. The beststudied cause is nonlocal choice, which e.g. is unavoidable in systems with autonomous processes. In this ..."
Abstract

Cited by 6 (1 self)
 Add to MetaCart
Abstract. MSC is a visual formalism for specifying the behavior of systems. To obtain implementations for individual processes, the MSC choice construction poses fundamental problems. The beststudied cause is nonlocal choice, which e.g. is unavoidable in systems with autonomous processes. In this paper we characterize two additional problematic classes of choice nodes. Based on these three classes we point out some errors in related work. Extending our work on pragmatic implementations of nonlocal choice, we motivate a different choice semantics which allows a little more behavior. Finally, inspired by practical case studies, we present the first implementation approach for nonlocal choice nodes that can handle arbitrary numbers of processes. 1
Time Scale Decomposition of Stochastic Process Algebra Models
 University of Twente
, 1997
"... Realistic models of computer and communication systems result in large, complex performance models. Compositionality, offered by stochastic process algebra constructs a model from submodels which are smaller and more tractable. We present a technique to exploit this structure in order to enhance the ..."
Abstract

Cited by 6 (0 self)
 Add to MetaCart
Realistic models of computer and communication systems result in large, complex performance models. Compositionality, offered by stochastic process algebra constructs a model from submodels which are smaller and more tractable. We present a technique to exploit this structure in order to enhance the solution of the model by decomposition of the underlying Markov process. The decomposition under consideration is time scale decomposition, based on Courtois's near complete decomposability. This work has been influenced by related work on stochastic Petri nets and presents a major advancement related to a preliminary version of this technique already presented at a workshop of this series. In particular, a transformation technique is developed which is based on a delayed choice operator and preserves equivalence. 1 Introduction Stochastic process algebras (SPA) are formal description techniques by which systems are modelled as an interaction of autonomous agents or components who engage i...
MSC and data
, 1998
"... The extension of the MSC language with more advanced data concepts is one of the current topics of discussion in the MSC standardization community. We discuss some problems and possibilities. By means of two case studies we study the practical consequences of our proposed approach. ..."
Abstract

Cited by 5 (1 self)
 Add to MetaCart
The extension of the MSC language with more advanced data concepts is one of the current topics of discussion in the MSC standardization community. We discuss some problems and possibilities. By means of two case studies we study the practical consequences of our proposed approach.