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Moyano F.,University of Malaga | Fernandez-Gago C.,University of Malaga | Baudry B.,French Institute for Research in Computer Science and Automation | Baudry B.,Certus Software nter | Lopez J.,University of Malaga
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

The Future Internet (FI) comprises scenarios where many heterogeneous and dynamic entities must interact to provide services (e.g., sensors, mobile devices and information systems in smart city scenarios). The dynamic conditions under which FI applications must execute call for self-adaptive software to cope with unforeseeable changes in the application environment. Models@run.time is a promising modeldriven approach that supports the runtime adaptation of distributed, heterogeneous systems. Yet frameworks that accommodate this paradigm have limited support to address security concerns, hindering their usage in real scenarios. We address this challenge by enhancing models@ run.time with the concepts of trust and reputation. Trust improves decision-making processes under risk and uncertainty and constitutes a distributed and flexible mechanism that does not entail heavyweight administration. This chapter introduces a trust and reputation framework that is integrated into a distributed component model that implements the models@run.time paradigm, thus allowing software components to include trust in their reasoning process. The framework is illustrated in a smart grid scenario. © Springer International Publishing Switzerland 2014 Source

Ali S.,Certus Software nter | Yue T.,Certus Software nter
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

The use of search algorithms requires the definition of a fitness function that guides the algorithms to find an optimal solution. The definition of a fitness function may require the use of a normalization function for various purposes such as assigning equal importance to various factors constituting a fitness function and normalizing only one factor of a fitness function to give it less/more importance than the others. In our previous work, we defined various branch distance functions (a commonly used heuristic in the literature at the code-level) corresponding to the constructs defined in the Object Constraint Language (OCL) to solve OCL constraints to generate test data for supporting automated Model-Based Testing (MBT). The definition of several of these distance functions required the use of a normalization function. In this paper, we extend the empirical evaluation reported in one of the works in the literature that compares the impact of using various normalization functions for calculating branch distances at the code-level on the performance of search algorithms.The empirical evaluation reported in this paper assesses the impact of the commonly used normalization functions for the branch distance calculation of OCL constraints at the model-level. Results show that for one of the newly studied algorithms Harmony Search (HS) and Random Search (RS), the use of the normalization functions has no impact on the performance of the search. However, HS achieved 100% success rates for all the problems, where RS obtained very poor success rates (less than 38%). Based on the results, we conclude that the randomness in creating a solution in search algorithms may mask the impact of using a normalization function. © IFIP International Federation for Information Processing 2014. Source

Behjati R.,Certus Software nter | Nejati S.,University of Luxembourg
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Configuration is a recurring problem in many domains. In our earlier work, we focused on architecture-level configuration of large-scale embedded software systems and proposed a methodology that enables engineers to configure products by instantiating a given reference architecture model. Products have to satisfy a number of constraints specified in the reference architecture model. If not, the engineers have to backtrack their configuration decisions to rebuild a configured product that satisfies the constraints. Backtracking configuration decisions makes the configuration process considerably slow. In this paper, we improve our earlier work and propose a backtrack-free configuration mechanism. Specifically, given a cycle-free generic reference architecture model, we propose an algorithm that computes an ordering over configuration parameters that yields a consistent configuration without any need to backtrack. We evaluated our approach on a simplified model of an industrial case study. We show that our ordering approach eliminates backtracking. It reduces the overall configuration time by both reducing the required number of value assignments, and reducing the time that it takes to complete one configuration iteration. Furthermore, we show that the latter has a linear growth with the size of the configuration problem. © IFIP International Federation for Information Processing 2015. Source

Yue T.,Certus Software nter | Ali S.,Certus Software nter
Software and Systems Modeling | Year: 2014

The Object Constraint Language (OCL) has been applied, along with UML models, for various purposes such as supporting model-based testing, code generation, and automated consistency checking of UML models. However, a lot of challenges have been raised in the literature regarding its applicability in industry such as extensive training, slow learning curve, and significant effort to use OCL due to lack of familiarity of practitioners. To confirm these challenges, empirical evidence is needed, which is severely lacking in the literature. To build such preliminary evidence, we report a controlled experiment that was designed to evaluate OCL by comparing it with Java; a programming language that has also been used to specify constraints on UML models. Results show that the participants using OCL perform as good as the participants working with Java in terms of three objective quality metrics (i.e., completeness, conformance and redundancy) and two subjective metrics (i.e., applicability and confidence level). In addition, the participants using OCL performed consistently well for all the constraints of varying complexity, while fluctuating results were obtained for the participants using Java for the same constraints. Based on the empirical evidence, we can conclude that it does not make much difference to use OCL or Java for specifying constraints on UML models. However, the participants working with OCL performed consistently well on specifying constraints of varying complexity suggesting that OCL can be used to model complicated constraints (commonly observed in industrial applications) with the same quality as for simpler constraints. Moreover, additional analyses on the constraints when using Java and OCL tools revealed that tools are needed to specify fully correct constraints that can be used to support automation. © 2014 Springer-Verlag Berlin Heidelberg Source

Fan Z.,Beihang University | Fan Z.,CAS Institute of Computing Technology | Yue T.,Certus Software nter | Zhang L.,Beihang University
Software and Systems Modeling | Year: 2016

Ship command and control systems (SCCSs) are composed of large-scale, complex, real-time and software-intensive systems that complete tasks collaboratively. Open architecture has been introduced to design the architecture of SCCSs and has been refined into functional architecture (FA) and technical architecture (TA) to meet architectural requirements such as adapting fast-speed functional and technical changes. Thereby, specifying the architecture of SCCSs, based on FA and TA, becomes a key issue for stakeholders of the domain. In this paper, we propose an architecture modeling methodology (named as SAMM) for describing the architecture of SCCSs. SAMM is derived by following a systematic and generic framework—modeling Goal, domain-specific Conceptual model, architecture Viewpoint, and architecture description Language (GCVL), which guides domain experts to devise domain-specific architecture modeling methodologies of large-scale software-intensive systems. SAMM contains three viewpoints and 22 models, and a UML/SysML-based architecture description language. An industrial application of SAMM, along with the subsequent application of the derived SAMM architecture model (i.e., a deployed SCCS prototype) was conducted to evaluate SAMM. A questionnaire-based survey was also conducted to subjectively evaluate whether SAMM meets the modeling goals and its applicability. Results show that SAMM meets all modeling goals and is easy to apply. © 2013, Springer-Verlag Berlin Heidelberg. Source

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