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ItemSemi-symbolic Simulation and Analysis of Deviation Propagation of Feature Coordination in Cyber-physical Systems( 2018-01-03)For studying the effects of deviations for uncertain inputs of systems, often multi-run simulation is employed, which is time-consuming. Unfortunately, such simulations also do not directly support the traceability of such effects. A semi-symbolic modeling approach based on Affine Arithmetic Forms allows the representation of uncertainty in terms of ranges. Simulations of such models directly include propagation of deviations and their traceability. This paper presents such a semi-symbolic model of a cyber-physical system including coordination of safety-critical and interacting features. For feature coordination, this model introduces handling discrete uncertainty with two different behavioral modes and their integration. Based on this model, a single simulation run allowed us studying the effects of several deviations. In addition, this modeling approach facilitates specific analyses of deviations based on the traceability information. As a result from simulation and analyses, we got a better understanding of the different deviation propagations within our model.
ItemAnalyzing the Instability of the Core Components of Software Projects( 2018-01-03)Open source software projects represent a significant source of existing pieces of software to be identified and used to implement new or emerging requirements. However, the high complexity of the existing software systems makes difficult the identification of software components to be reused in other systems and the evaluation of their quality. This paper proposes an approach aiming at identifying the core components of a software system and proposing and evaluating some metrics for measuring the evolution of their architecture instability across multiple releases. Then, the paper analyses how the architecture of core components of a software system evolves respect to the whole system. It also investigates the different factors influencing the instability of the core components and it verifies if it decreases across multiple releases assumed that this is a good indication that they can constitute a good candidate to be reused.