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Software build systems tackle the problem of building software from sources in a way which is sound (when a build completes successfully, the relations between the generated and source files are as specified) and optimal (only genuinely required rebuilding steps are done). In this paper, we explain and exploit the connection between software build and the megamodel consistency problem. The model-driven development of systems involves multiple models, metamodels and transformations. Transformations—which may be bidirectional—specify, and provide means to enforce, desired "consistency" relationships between models. We can describe the whole configuration using a megamodel. As development proceeds, and various models are modified, we need to be able to restore consistency in the megamodel, so that the consequences of decisions first recorded in one model are appropriately reflected in the others. At the same time, we need to minimise the amount of recomputation needed; in particular, we would like to avoid reapplying a transformation when no relevant changes have occurred in the models it relates. The megamodel consistency problem requires flexibility beyond what is found in conventional software build, because different results are obtained depending on which models are allowed to be modified and on the order and direction of transformation application. In this paper, we propose using an orientation model to make important choices explicit. We show how to extend the formalised build system pluto to provide a means of restoring consistency in a megamodel, that is, in appropriate senses, flexible, sound and optimal. [ABSTRACT FROM AUTHOR]

The model-driven development of systems involves multiple models, metamodels and transformations, and relationships between them. A bidirectional transformation (bx) is usually defined as a means of maintaining consistency between "two (or more)" models. This includes cases where one model may be generated from one or more others, as well as more complex ("symmetric") cases where models record partially overlapping information. In recent years, binary bx, those relating two models, have been extensively studied. Multiary bx, those relating more than two models, have received less attention. In this paper, we consider how a multiary consistency relation may be defined in terms of binary consistency relations and how consistency restoration may be carried out on a network of models and relationships between them. In particular, we consider the circumstances under which we can prove non-interference between several bidirectional transformations that impact on the same model and how the use of a more refined notion of consistency can help in cases where this is not possible. In the process, we develop an abstract theory of parts of a model that are read or modified by a bidirectional transformation. We relate the work to megamodelling and discuss further research that is needed. [ABSTRACT FROM AUTHOR]

Teaching modeling in computer science is complicated. Many factors contribute, and are related in diverse ways. We regard some combinations as more successful than others, but we also value diversity, and we struggle to elucidate the relationships and our value structure. Similar remarks apply to the study of biological ecosystems. This contribution views teaching modeling as an ecosystem: we push the analogy as far as we can, with the intention of provoking readers’ thought in unaccustomed directions, which may perhaps lead to interesting advances. We identify the factors that contribute to the ecosystem and establish some relationships between the constituent factors. We discuss some of the factors that need further work and improvement. Finally, we discuss what it should mean for the ecosystem of the teaching of modeling to be healthy. [ABSTRACT FROM AUTHOR]

The QVT Relations (QVT-R) transformation language allows the definition of bidirectional model transformations, which are required in cases where two (or more) models must be kept consistent in the face of changes to either or both. A QVT-R transformation can be used either in checkonly mode, to determine whether a target model is consistent with a given source model, or in enforce mode, to change the target model. A precise understanding of checkonly mode transformations is prerequisite to a precise understanding of enforce mode transformations, and this is the focus of this paper. In order to give semantics to checkonly QVT-R transformations, we need to consider the overall structure of the transformation as given by when and where clauses, and the role of trace classes. In the standard, the semantics of QVT-R are given both directly, and by means of a translation to QVT Core, a language which is intended to be simpler. In this paper, we argue that there are irreconcilable differences between the intended semantics of QVT-R and those of QVT Core, so that no translation from QVT-R to QVT Core can be semantics-preserving, and hence no such translation can be helpful in defining the semantics of QVT-R. Treating QVT-R directly, we propose a simple game-theoretic semantics. We demonstrate its behaviour on examples and show how it can be used to prove an example result comparing two QVT-R transformations. We demonstrate that consistent models may not possess a single trace model whose objects can be read as traceability links in either direction. We briefly discuss the effect of variations in the rules of the game, to elucidate some design choices available to the designers of the QVT-R language. [ABSTRACT FROM AUTHOR]

We consider the OMG’s queries, views and transformations standard as applied to the specification of bidirectional transformations between models. We discuss what is meant by bidirectional transformations, and the model-driven development scenarios in which they are needed. We analyse the fundamental requirements on tools which support such transformations, and discuss some semantic issues which arise. In particular, we show that any transformation language sufficient to the needs of model-driven development would have to be able to express non-bijective transformations. We argue that a considerable amount of basic research is needed before suitable tools will be fully realisable, and suggest directions for this future research. [ABSTRACT FROM AUTHOR]

We compareHaskellwith StandardMLas programming languages for verification tools based on our experience developing the verification platformTruthinHaskelland the Edinburgh Concurrency Workbench (CWB) in StandardML. We review not only technical language features but also the “worlds” of the languages, for example, the availability of compilers, tools, and libraries. We also discuss the merits and difficulties of comparing programming languages in this wide sense and support our view thatTruthand theCWBare similar enough to justify the conclusions drawn in this paper. [ABSTRACT FROM AUTHOR]

Binary associations between classifiers are among the most fundamental of UML concepts. However, there is considerable room for disagreement concerning what an association is, semantically; it turns out that at least two different notions are called Associations. This confusion of concepts gives rise to unnecessary complication and ambiguity in the language, which have implications for the modeller because they can result in serious misunderstandings of static structure diagrams; similarly, they have implications for tool developers. In this paper we explore these issues, suggest improvements and clarifications, and demonstrate side-benefits that would accrue. [ABSTRACT FROM AUTHOR]

This special section is devoted to a selection of journal versions of papers that appeared originally in the Proceedings of the 8th International Conference on Tools and Algorithms for the Construction and Analysis of Systems (TACAS), which took place in Grenoble, France in April 2002 as a constituent event of the European joint conferences on Theory and Practice of Software (ETAPS). All papers are relevant to the field of systems validation. The first three papers advance and extend model-checking techniques, the fourth presents algorithms for run-time verification, and the last paper is about animation and test generation for formal system specifications. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including practical problem for the adoption of model-driven development, comparison of specification-based and heuristic-based composing techniques and application of the UML profile for MARTE.

The article presents an overview of the research papers which were presented during the 2003 Unified Modelling Language conference. A systematic way of designing interactions by stepwise refinement was developed. One paper describes a snapshot sequence language which has been implemented to help designers to make better use of complex snapshots of a given model. One paper describes the author's experiences with a tool called Netsilon which has been developed to apply the model-driven engineering approach to web applications.