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Bidirectional transformations (bx) are a mechanism for maintaining the consistency of two (or more) related sources of information, such as models in model-driven development, database schemas, or programs. Bx technologies have been developed for practical engineering purposes in many diverse fields. Different disciplines such as programming languages, graph transformations, software engineering, and databases have contributed to the concepts and theory of bx. However, so far, most efforts have been focused on the case where exactly two information sources must be kept consistent; the case of more than two has usually been considered as an afterthought. In many practical scenarios, it is essential to work with more than two information sources, but the community has hardly started to identify and address the research challenges that this brings. Driven by the practical needs and usage scenarios from industry, this Dagstuhl Seminar aimed to identify the challenges, issues and open research problems for multidirectional model transformations and synchronisations and sketch a road map for developing relevant concepts, theories and tools. The report contains an executive summary of the seminar, reports from its working groups, as well as descriptions of industrial and academic case studies that motivated the discussions.

This paper presents a model-based testing framework for probabilistic systems. We provide algorithms to generate, execute and evaluate test cases from a probabilistic requirements model. In doing so, we connect ioco-theory for model-based testing and statistical hypothesis testing: our ioco-style algorithms handle the functional aspects, while statistical methods, using $$\chi ^2$$i¾?2 tests and fitting functions, assess if the frequencies observed during test execution correspond to the probabilities specified in the requirements. Key results of our paper are the classical soundness and completeness properties, establishing the mathematical correctness of our framework; Soundness states that each test case is assigned the right verdict. Completeness states that the framework is powerful enough to discover each probabilistic deviation from the specification, with arbitrary precision. We illustrate the use of our framework via two case studies.

Bidirectional transformations bx are a mechanism for maintaining the consistency of two (or more) related sources of information. Researchers from many different areas of computer science including databases (DB), graph transformations (GT), software engineering (SE), and programming languages (PL) are actively investigating the use of bx to solve a diverse set of problems. Although researchers have been actively working on bidirectional transformations in the above mentioned communities for many years already, there has been very little cross-discipline interaction and cooperation so far. The purpose of a first International Meeting on Bidirectional Transformations (GRACE-BX), held in December 2008 near Tokyo, was therefore to bring together international elites, promising young researchers, and leading practitioners to share problems, discuss solutions, and open a dialogue towards understanding the common underpinnings of bx in all these areas. While the GRACE-BX meeting provided a starting point for exchanging ideas in different communities and confirmed our believe that there is a considerable overlap of studied problems and developed solutions in the identified communities, the Dagstuhl Seminar 11031 on ``Bidirectional Transformations'' also aimed at providing a place for working together to define a common vocabulary of terms and desirable properties of bidirectional transformations, develop a suite of benchmarks, solve some challenging problems, and launch joint efforts to form a living bx community of cooperating experts across the identified subdisciplines. This report documents the program and the outcomes of Dagstuhl Seminar 11031 with abstracts of tutorials, working groups, and presentations on specific research topics.

Performance, dependability and quality of service (QoS) are prime aspects of the UML modeling domain. To capture these aspects effectively in a modeling language requires easy-to-use support for the specification and analysis of randomly varying behaviors. This paper introduces an extension of UML statecharts with randomly varying durations, by enriching a specific syntactic construct: The after operator is equipped with (discrete or continuous) probability distributions, determining the duration of the delay caused by this operator. The semantics of this extension is given in terms of a variant of stochastic automata. It is shown how existing model-checking tools can be used to calculate model-inherent QoS characteristics automatically. We study a UML model of an automatic teller machine scenario using this approach.

Lecture Notes in Computer Science, 9633, ISSN:0302-9743, ISSN:1611-3349, Fundamental Approaches to Software Engineering, ISBN:978-3-662-49665-7, ISBN:978-3-662-49664-0

Performance analysis of computing systems, in particular distributed computing systems, is a complex process. Analysing the complex flows and interactions between a set of distributed processing nodes is a non-trivial task. The problem is exacerbated by the addition of continuous system functions that are time dependent, such as communication between components in the form of multimedia streams of video and audio data. Quality-of-Service (QoS) specifications define constraints on such communications and describe the required patterns of data transfer. By making use of these specifications as part of the performance analysis process it is possible to add significant confidence to predictions about the correct (required) operation of a distributed system. This paper presents a method for designing distributed multimedia systems, including the specification of QoS, using the ODP framework and UML and describes a technique for verifying the QoS specification against the designed functional behaviour of the system using Timed Automata.