Browsing by Author "Schneider, Daniel"
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Item Multidirectional modular conditional safety certificates(Springer Verlag, 2015) Amorim, Tiago; Ruiz, Alejandra; Dropmann, Christoph; Schneider, Daniel; van Gulijk, Coen; Koornneef, Floor; QuantumOver the last 20 years, embedded systems have evolved from closed, rather static single-application systems towards open, flexible, multi-application systems of systems. While this is a blessing from an application perspective, it certainly is a curse from a safety engineering perspective as it invalidates the base assumptions of established engineering methodologies. Due to the combinatorial complexity and the amount of uncertainty encountered in the analysis of such systems, we believe that more potent modular safety approaches coupled with adequate runtime checks are required. In this paper, we investigate the possibility of an integrated contract-based approach covering vertical dependencies (between platform and application) and horizontal dependencies (between applications) in order to efficiently assure the safety of the whole system of systems through modularization. We integrate both concepts using state-of-the-art research and showcase the application of the integrated approach based on a small industrial case study.Item Runtime safety assurance for adaptive cyber-physical systems: Conserts M and ontology-based runtime reconfiguration applied to an automotive case study(IGI Global, 2017-07-20) Amorim, Tiago; Ratasich, Denise; Macher, Georg; Ruiz, Alejandra; Schneider, Daniel; Driussi, Mario; Grosu, Radu; QuantumCyber-Physical Systems (CPS) provide their functionality by the interaction of various subsystems. CPS usually operate in uncertain environments and are often safety-critical. The constituent systems are developed by different stakeholders, who - in most cases - cannot fully know the composing parts at development time. Furthermore, a CPS may reconfigure itself during runtime, for instance in order to adapt to current needs or to handle failures. The information needed for safety assurance is only available at composition or reconfiguration time. To tackle this assurance issue, the authors propose a set of contracts to describe components' safety attributes. The contracts are used to verify the safety robustness of the parts and build a safety case at runtime. The approach is applied to a use case in the automotive domain to illustrate the concepts. In particular, the authors demonstrate safety assurance at upgrade and reconfiguration on the example of ontology-based runtime reconfiguration (ORR). ORR substitutes a failed service by exploiting the implicit redundancy of a system.Item VITALAS at TRECVID-2009(2009) Diou, Christos; Stephanopoulos, George; Dimitriou, Nikos; Panagiotopoulos, Panagiotis; Papachristou, Christos; Delopoulos, Anastasios; Rode, Henning; Tsikrika, Theodora; de Vries, Arjen P.; Schneider, Daniel; Schwenninger, Jochen; Viaud, Marie Luce; Saulnier, Agnès; Altendorf, Peter; Schröter, Birgit; Elser, Matthias; Rego, Angel; Rodriguez, Alex; Martínez, Cristina; Etxaniz, Iñaki; Dupont, Gérard; Grilhères, Bruno; Martin, Nicolas; Boujemaa, Nozha; Joly, Alexis; Enficiaud, Raffi; Verroust, Anne; Selmi, Souheil; Khadhraoui, Mondher; CIBERSEC&DLT; HPAThis paper describes the participation of VITALAS in the TRECVID-2009 evaluation where we submitted runs for the High-Level Feature Extraction (HLFE) and Interactive Search tasks. For the HLFE task, we focus on the evaluation of low-level feature sets and fusion methods. The runs employ multiple low-level features based on all available modalities (visual, audio and text) and the results show that use of such features improves the retrieval effectiveness significantly. We also use a concept score fusion approach that achieves good results with reduced low-level feature vector dimensionality. Furthermore, a weighting scheme is introduced for cluster assignment in the "bag-of-words" approach. Our runs achieved good performance compared to a baseline run and the submissions of other TRECVID-2009 participants. For the Interactive Search task, we focus on the evaluation of the integrated VITALAS system in order to gain insights into the use and effectiveness of the system's search function-alities on (the combination of) multiple modalities and study the behavior of two user groups: professional archivists and non-professional users. Our analysis indicates that both user groups submit about the same total number of queries and use the search functionalities in a similar way, but professional users save twice as many shots and examine shots deeper in the ranked retrieved list.The agreement between the TRECVID assessors and our users was quite low. In terms of the effectiveness of the different search modalities, similarity searches retrieve on average twice as many relevant shots as keyword searches, fused searches three times as many, while concept searches retrieve even up to five times as many relevant shots, indicating the benefits of the use of robust concept detectors in multimodal video retrieval.