OMG's PSCS specification extends the execution model of fUML by precise runtime semantics for UML composite structures. With composite structures being a concept for describing structural properties of a model, the majority of execution semantics specified by PSCS concern analysis and processing of static information about the model's fine-grained structure at runtime. Using Model-To-Text-Transformation to generate source code, which serves as an input for PSCS's actual execution environment, the runtime level of model execution can be relieved by outsourcing analysis and processing of static information to the level of code generation. By inserting this step of preprocessing, the performance of the actual model execution at runtime can be improved. This paper introduces an implementation of the PSCS specification for C++ based on code generation using Model-to-Text-Transformation. Moreover, it presents a set of test models validating the correct functionality of the implementation a s well as a performance benchmark. The PSCS implementation presented by this paper was developed as a part of the MDE4CPP* project.

One of the goals of the Foundational UML Subset (fUML) is a consistent and well-defined execution of UML activity diagrams. However, the specification is not done in a formal mathematical model and leaves room for implementation-specific tool details. This paper shows how this may lead to problems for concurrent program semantics. To this end, the paper introduces a transformation and basic analysis methods for activity diagrams under the current fUML sequential execution semantics. The analysis is conducted using Petri nets, which are mathematical models with a graphical representation to describe distributed systems. There are numerous well-established analysis methods to validate specific desirable properties of a concurrent program including liveliness, the absence of deadlocks, fairness, mutual exclusion, and detection of unreachable states. In this paper, we show that the intuitive translation to Petri nets does not fit the current fUML execution implementation; therefore, we i ntroduce a new model-to-model transformation realized with QVTo, that translates a set of the most used fUML elements to Petri nets. Moreover, we propose methods to analyze the models with the tool TimeNET.

This paper shows and discusses the realization of advanced data structures used in the UML specification (namely subsets, unions, and subset-unions) for a C++ execution engine. Those data structures have been realized thanks to the use of variadic templates, which were first introduced in C++11. Thanks to those templates which allow to take as parameters a non-fixed number of elements in an elegant manner, it has been possible to automatically generate from the Ecore and UML ecore models type-safe data structures which avoid elements being duplicated or the generation of additional lists during run-time. A performance analysis is presented to show how our implementation behaves compared to the other possible approaches.

This paper introduces an execution engine that is able to run fUML models, described by a subset of UML's class and activity diagrams' elements. The execution engine is realized in C++, which leads, in certain conditions, to better memory efficiency and performance of the generated code, compared for example to the fUML standard implementation in Java. As it does not use any platform specific code, it is possible to compile it on any C++ compliant platform. The paper then shows how the engine has been applied to a simulated annealing optimization heuristic as a validation example and finally a performance evaluation regarding occupied memory, storage requirements, and execution time is carried out.

The optimization of complex systems as well as other design methods require a description of the system parameters, or the design space. Explicit encoding of all possible variants is practically impossible, thus an implicit method is needed. While this is easy for purely numerical parameters and a fixed number of them as usually assumed in direct or indirect optimization, it is quite hard for systems in which the architecture and thus the structure of the parameters themselves can be varied. This paper introduces an approach to specify system architecture variants in a concise way and proposes a UML profile for this task. Standard UML meta model elements are used for the description of variant-specific stereotypes. An example of a variant specification for a communication network model is presented.