Laboratoire d’analyse et d’architecture des systèmes
J.M.Larré, K.CABRERA CASTILLOS, J.GUIOCHET
Rapport LAAS N°17404, Novembre 2017, 18p.
Y.MOTIE, A.NKETSA, P.TRUILLET
Manifestation avec acte : European Simulation and Modelling Conference ( ESM ) 2017 du 25 octobre au 27 octobre 2017, Lisbonne (Portugal), Octobre 2017, 7p. , N° 17375
It is common accepted that complex systems or cyber-physical systems need co-simulation for their study. Further more, they are made of heterogeneous subsystems that have to exchange data. Usually each subsystem is modeled using specific tools, environments and sim-ulators. The simulators have to interoperate to realize all the simulation of the system. It is known that in-teroperativity is a broad and complex subject. Interop-erability is a strong commitment as the communication solution in heterogeneous systems. This paper describes a co-simulation framework interoperability based FMI (Functional Mock up Interface) standard for the structural part and data mediation for semantic part. We present a case study for Neo-Campus project that shows how the framework helps to build the semantic interop-erability of a cyberphysical system.
M.LI, G.ZHU, Y.SAVARIA, M.LAUER
Ecole Montréal, TSF
Revue Scientifique : IEEE Transactions on Industrial Informatics, Vol.13, N°5, pp.2118-2129, Octobre 2017, DOI: 10.1109/TII.2017.2732345 , N° 17317
AFDX is a safety critical network in which a redundancy management mechanism is employed to enhance the reliability of the network. However, as stated in the ARINC664-P7 standard, there still exists a potential problem, which may fail redundant transmissions due to sequence inversion in the redundant channels. In this paper, we explore this phenomenon and provide its mathematical analysis. It is revealed that the variable jitter and the transmission latency difference between two successive frames are the two main sources of sequence inversion. Thus, two methods are proposed and investigated to mitigate the effects of jitter pessimism, which can eliminate the potential risk. A case study is carried out and the obtained results confirm the validity and applicability of the developed approaches.
C.BERTERO, M.ROY, C.SAUVANAUD, G.TREDAN
Manifestation avec acte : International Symposium on Software Reliability Engineering ( ISSRE ) 2017 du 23 octobre au 26 octobre 2017, Toulouse (France), Octobre 2017, 10p. , N° 17295
Event logging is a key source of information on a system state. Reading logs provides insights on its activity, assess its correct state and allows to diagnose problems. However, reading does not scale: with the number of machines increasingly rising, and the complexification of systems, the task of auditing systems' health based on logfiles is becoming overwhelming for system administrators. This observation led to many proposals automating the processing of logs. However, most of these proposal still require some human intervention, for instance by tagging logs, parsing the source files generating the logs, etc. In this work, we target minimal human intervention for logfile processing and propose a new approach that considers logs as regular text (as opposed to related works that seek to exploit at best the little structure imposed by log formatting). This approach allows to leverage modern techniques from natural language processing. More specifically, we first apply a word embedding technique based on Google's word2vec algorithm: logfiles' words are mapped to a high dimensional metric space, that we then exploit as a feature space using standard classifiers. The resulting pipeline is very generic, computationally efficient, and requires very little intervention. We validate our approach by seeking stress patterns on an experimental platform. Results show a strong predictive performance (≈ 90% accuracy) using three out-of-the-box classifiers.
Rapport LAAS N°17329, Septembre 2017, 17p.
N.GE, M.PANTEL, S.DAL ZILIO
Beihang University, IRIT-ENSEEIHT, VERTICS
Manifestation avec acte : International Symposium on Theoretical Aspects of Software Engineering ( TASE ) 2017 du 13 septembre au 15 septembre 2017, Sophia Antipolis (France), Septembre 2017, 8p. , N° 17308
To ease the expression of real-time requirements, Dwyer, and then Konrad, studied a large collection of existing systems in order to identify a set of real-time property patterns covering most of the useful use cases. The goal was to provide a set of reusable patterns that system designers can instantiate to express requirements instead of using complex temporal logic formulas. A limitation of this approach is that the choice of patterns is more oriented towards expressiveness than efficiency; meaning that it does not take into account the computational complexity of checking patterns. For this purpose, we define a set of verification-dedicated, atomic property patterns for qualitative and quantitative real-time requirements. End-user requirements can then be expressed as a composition of these patterns using a predefined meta-model and a mapping library. These properties can be checked efficiently using a set of elementary observers and a model checking approach.
A.ALBORE, S.DAL ZILIO, G.INFANTES, C.SEGUIN, P.VIRELIZIER
VERTICS, RIS, ONERA, IRT
Manifestation avec acte : International Symposium on Model-Based Safety and Assessment ( IMBSA ) 2017 du 11 septembre au 13 septembre 2017, Trento (Italie), Septembre 2017, 15p. , N° 17339
The design of complex safety critical systems raises new technical challenges for the industry. As systems become more complex—and include more and more interacting functions—it becomes harder to evaluate the safety implications of local failures and their possible propagation through a whole system. That is all the more true when we add time to the problem, that is when we consider the impact of computation times and delays on the propagation of failures. We describe an approach that extends models developed for Safety Analysis with timing information and provide tools to reason on the correctness of temporal safety conditions. Our approach is based on an extension of the AltaRica language where we can associate timing constraints with events and relies on a translation into a realtime model-checking toolset. We illustrate our method with an example that is representative of safety architectures found in critical systems.
R.WANG, J.GUIOCHET, G.MOTET
Manifestation avec acte : International Conference on Computer Safety, Reliability and Security ( SafeComp ) 2017 du 12 septembre au 15 septembre 2017, Trento (Italie), Septembre 2017, 14p. , N° 17189
Confidence in safety critical systems is often justified by safety arguments. The excessive complexity of systems nowadays introduces more uncertainties for the arguments reviewing. This paper proposes a framework to support the argumentation assessment based on experts' decision and confidence in the decision for the lowest level claims of the arguments. Expert opinion is extracted and converted in a quantitative model based on Dempster-Shafer theory. Several types of argument and associated formulas are proposed. A preliminary validation of this framework is realized through a survey for safety experts.
J.ROUX, E.ALATA, V.NICOMETTE, M.KAANICHE
Manifestation avec acte : European Dependable Computing Conference ( EDCC ) 2017 du 04 septembre au 08 septembre 2017, Genève (Suisse), Septembre 2017, 4p. , N° 17230
Nowadays, more and more Internet-of-Things (IoT) smart products, interconnected through various wireless communication technologies (Wifi, Bluetooth, Zigbee, Z-wave, etc.) are integrated in daily life, especially in homes, factories, cities, etc. Such IoT technologies have become very attractive with a large variety of new services offered to improve the quality of life of the endusers or to create new economic markets. However, the security of such connected objects is a real concern due to weak or flawed security designs, configuration errors or imperfect maintenance. Moreover, the vulnerabilities discovered in IoT products are often difficult to eliminate because, most of the time, they cannot be patched easily. Therefore, protection mechanisms are needed to mitigate the potential risks induced by such objects in private and public connected areas. In this paper, we propose a novel approach to detect potential attacks in smart places (e.g. smart homes) by detecting deviations from legitimate communication behavior, in particular at the physical layer. The proposed solution is based on the profiling and monitoring of the Radio Signal Strenght Indication (RSSI) associated to the wireless transmissions of the connected objects. A machine learning neural network algorithm is used to characterize legitimate communications and to identify suspiscious scenarios. We show the feasibility of this approach and discuss some possible application cases.
A.KRITIKAKOU, T.MARTY, M.ROY
INRIA Rennes, TSF
Revue Scientifique : ACM Transactions on Design Automation of Electronic Systems, Vol.23, N°2, 13p., Septembre 2017 , N° 17377
In real-time mixed-critical systems, Worst-Case Execution Time analysis (WCET) is required to guarantee that timing constraints are respected —at least for high criticality tasks. However, the WCET is pessimistic compared to the real execution time, especially for multicore platforms. As WCET computation considers the worst-case scenario, it means that whenever a high criticality task accesses a shared resource in multi-core platforms, it is considered that all cores use the same resource concurrently. This pessimism in WCET computation leads to a dramatic under utilization of the platform resources, or even failing to meet the timing constraints. In order to increase resource utilization while guaranteeing real-time guarantees for high criticality tasks, previous works proposed a run-time control system to monitor and decide when the interferences from low criticality tasks cannot be further tolerated. However, in the initial approaches, the points where the controller is executed were statically predefined. In this work, we propose a dynamic run-time control which adapts its observations to on-line temporal properties, increasing further the dynamism of the approach, and mitigating the unnecessary overhead implied by existing static approaches. Our dynamic adaptive approach allows to control the ongoing execution of tasks based on run-time information, and increases further the gains in terms of resource utilization compared with static approaches.