Conformance testing of FMI calling sequence for simulation environments

Exchanging simulation models is currently of utmost importance.To improve interoperability between suppliers and original equipment manufacturers(OEMs),the functional mock-up interface(FMI)is exchanged in a standard format called functional mock-up unit(FMU).Since its first release,many simulation tools took the initiative to support FMI.However,since then,there have been many complaints stating that exchanging models via FMI does not work as stable as expected.The reason usually turned out to be the implementation of tool vendors that sometimes fail to comply with the standard fully.This paper introduces a methodology for testing FMI compliance of importing simulation tools using a set of reference FMUs.The standard defines the implementation of FMI functions calling sequence in a state machine.Therefore,conformance testing(also called fault detection)from automata theory is utilized to produce reference FMUs based on the FMI state-machine.

Pragmatic model transformations for refactoring in Scilab/Xcos

Model-Based Development has become an industry wide standard paradigm.As an open source alternative,Scilab/Xcos is being widely employed as a hybrid dynamic systems modeling tool.With the increasing efficiency in implementation using graphical model development and code generation,the modeling and simulation community is struggling with assuring quality as well as maintainability and extendibility.Refactoring is defined as an evolutionary modernization activity where,most of the time,the structure of the artifact is changed to alter its quality characteristics,while keeping its behavior unchanged.It has been widely established as a technique for textual programming languages to improve the code structure and quality.While refactoring is also regarded as one of the key practices of model engineering,the methodologies and approaches for model refactoring are still under development.Architecture-Driven Modernization(ADM)has been introduced by the software engineering community as a model-based approach to software modernization,in which the implicit information that lies in software artifacts is extracted to models and model transformations are applied for modernization tasks.Regarding refactoring as a low level modernization task,the practices from ADM are adaptable.Accordingly,this paper proposes a model-based approach for model refactoring in order to come up with more efficient and effective model refactoring methodology that is accessible and extendable by modelers.Like other graphical modeling tools,Scilab/Xcos also possesses a formalized model specification conforming to its implicit metamodel.Rather than proposing another metamodel for knowledge extraction,this pragmatic approach proposes to conduct in place model-to-model transformations for refactoring employing the Scilab/Xcos model specification.To construct a structured model-based approach,the implicit Scilab/Xcos metamodel is explicitly presented utilizing ECORE as a meta-metamodel.Then a practical model transformation approach is established based on Scilab scripting.A Scilab toolset is provided to the modeler for in-place model-to-model transformations.Using a sample case study,it is demonstrated that proposed model transformation functions in Scilab provide a valuable refactoring tool.