Implementing QVT-R bidirectional model transformations using alloy

QVT Relations (QVT-R) is the standard language proposed by the OMG to specify bidirectional model transformations. Unfortunately, in part due to ambiguities and omissions in the original semantics, acceptance and development of effective tool support has been slow. Recently, the checking semantics of QVT-R has been clarified and formalized. In this paper we propose a QVT-R tool that complies to such semantics. Unlike any other existing tool, it also supports meta-models enriched with OCL constraints (thus avoiding returning ill-formed models), and proposes an alternative enforcement semantics that works according to the simple and predictable “principle of least change”. The implementation is based on an embedding of both QVT-R transformations and UML class diagrams (annotated with OCL) in Alloy, a lightweight formal specification language with support for automatic model finding via SAT solving.Fundação para a Ciência e a Tecnologi

Comparing transformation languages for the implementation of certified model transformations

Precise specifications are needed for verifying and certifying the correct behavior of critical systems. However, traditional proofreading and test based verification techniques are usually not exhaustive and as systems become more complex, their coverage is less and less adequate. Use of models allows early verification, validation and automated building of "correct by construction" systems. Our work targets formal specification and verification of model transformations. In a previous paper we tackled the problem of writing formal speci- fications for model transformations independently to the implementation technique. In this paper we investigate the implementation phase of these specifications as model transforma- tions using traditional MDE techniques and the difficulties encountered while generating the verification materials

Teaching MDE through the Formal Verification of Process Models

International audienceModel Driven Engineering (MDE) and formal methods (FM) play a key role in the development of Safety Critical Systems (SCS). They promote user oriented abstraction and formal specification using Domain Specific Modeling Languages (DSML), early Validation and formal Verification (V&V) using efficient dedicated technologies and Automatic Code and Documentation Generation. Their combined use allow to improve system qualities and reduce development costs. However, in most computer science curriculae, both domains are usually taught independently. MDE is associated to practical software engineering and FM to theoretical computer science. This contribution relates a course about MDE for SCS development that bridges the gap between these domains. It describes the content of the course and provides the lessons learned from its teaching. It focuses on early formal verification using model checking of a DSML for development process modeling. MDE technologies are illustrated both on language engineering for CASE tool development and on development process modeling. The case study also highlights the unification power of MDE as it does not target traditional executable software

Integrating an Online Configuration Checker with Existing Management Systems : Application to CIM/WBEM Environments

National audienceRuntime configuration validation is a critical requirement if we are to build reliable self-adaptive management systems. This paper presents a generic framework that includes a runtime configuration checker built upon a high-level language dedicated to the specification of configurations and validity constraints. In addition, we describe a methodology for using this framework and integrating the configuration checker with existing management systems. In particular, we show how we use the framework to enrich a CIM/WBEM management environment with automatic runtime configuration validation against a defined set of constraints guarding structural correctness and service behavior conformance. Our experiments with management models conforming to the CIM Virtual System profile show viable results demonstrating the feasibility of our approach

Least - change bidirectional model transformation With QVT- R and ATL

QVT Relations (QVT-R) is the standard language proposed by the OMG to specify bidirectional model transformations. Unfortunately, in part due to ambiguities and omissions in the original semantics, acceptance and development of effective tool support has been slow. Recently, the checking semantics of QVTR has been clarified and formalized. In this article we propose a QVT-R tool that complies to such semantics. Unlike any other existing tool, it also supports metamodels enriched with OCL constraints (thus avoiding returning ill-formed models), and proposes an alternative enforcement semantics that works according to the simple and predictable “principle of least change”. The implementation is based on an embedding of both QVT-R transformations and UML class diagrams (annotated with OCL) in Alloy, a lightweight formal specification language with support for automatic model finding via SAT solving. We also show how this technique can be applied to bidirectionalize ATL, a popular (but unidirectional) model transformation language.This work is funded by ERDF-European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by national funds through the FCT-Fundacao para a Ciencia e a Tecnologia (Portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER-020532. The first author is also sponsored by FCT grant SFRH/BD/69585/2010. The authors would also like to thank all anonymous reviewers for the valuable comments and suggestions

A Lumped Parameter Model for the Pressure and Vibration Analysis of Variable Displacement Vane Pumps

This PhD thesis presents a lumped parameter model able to simulate the vibrational behavior of a wide range of variable displacement vane pumps. The vibration analysis of the rotating parts is carried out through a planar model with three degrees of freedom. It takes into account the variability of the pressure loads acting on the rotor shaft, the hydrodynamic journal bearing reactions, the friction due to viscous actions and contact forces, the rotor shaft stiffness and damping, the variation of the pump geometry with respect to working condition and all the inertia actions. In particular, the computation of pressure forces and torques is allowed by the preliminary evaluation of the variable pressure field acting inside the pump, obtained through a model based on an Euler’s approach with 26 control volumes. Thus, the present model makes it possible to define the pressure field acting inside the pump, and calculate the rotor shaft accelerations, as well as the journal bearing reaction forces and the motor drive torque absorbed by the pump in working condition. The test campaign and the validation method are then described: an original assessment technique based on the comparison of pump casing accelerations is proposed. Finally, some important simulation results are reported as an example of application. The main original contribution of this work concerns the development of a nonlinear model of variable displacement vane pumps including all the important dynamic effects in the same model, with the aim at taking into account their iterations. This can be important in order to foresee the influence of working conditions and design modifications on the pump vibrational behavior. In this sense the developed lumped parameter model could be a very useful tool in prototype design, in order to identify the origin of unwanted dynamic effects