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This paper deals with the design of robust model-based fault detection and isolation (FDI) systems for atmospheric reentry vehicles. This work draws expertise from actions undertaken within a project at the European level, which develops a collaborative effort between the University of Bordeaux, the European Space Agency, and European Aeronautic Defence and Space Company Astrium on innovative and robust strategies for reusable launch vehicles (RLVs) autonomy. Using an H∞/H- setting, a robust residual-based scheme is developed to diagnose faults on the vehicle wing-flap actuators. This design stage is followed by an original and specific diagnosis-oriented analysis phase based on the calculation of the generalized structured singular value. The latter provides a necessary and sufficient condition for robustness and FDI fault sensitivity over the whole vehicle flight trajectory. A key feature of the proposed approach is that the coupling between the in-plane and out-of-plane vehicle motions, as well as the effects that faults could have on the guidance, navigation, and control performances, are explicitly taken into account within the design procedure. The faulty situations are selected by a prior trimmability analysis to determine those for which the remaining healthy control effectors are able to maintain the vehicle around its center of gravity. Finally, some performance indicators including detection time, required onboard computational effort, and CPU time consumption are assessed and discussed. Simulation results are based on a nonlinear benchmark of the HL-20 vehicle under realistic operational conditions during the autolanding phase. The Monte Carlo results are quite encouraging, illustrating clearly the effectiveness of the proposed technique and suggesting that this solution could be considered as a viable candidate for future RLV programs. [ABSTRACT FROM AUTHOR]

Here we present first-order results detailing the Anatolian crustal from receiver function analysis of data from approximately 300 stations within Turkey. Seismic data from the Kandilli Observatory array (KOERI; KO), the National Seismic Network of Turkey (AFAD-DAD; TU) and available IRIS data from the Northern Anatolian Fault experiment (YL) for the period between 2005 and 2010 is analysed. We calculate receiver functions in the frequency domain using water-level deconvolution. The results are analysed using a combination of H–K stacking and depth stacking to determine robust Moho conversion depths and VP/Vs ratios across Anatolia. We detect a deep Moho in eastern Anatolia of up to ∼55 km, a generally normal Moho in Central Anatolia of ∼37–47 km and a thinned Moho in western Anatolia and Cyprus of ∼30 km. The VP/Vs ratio across the Anatolian Plate is generally slightly elevated; regions of extremely high VP/Vs ratio (>1.85) can be associated with recent volcanism in eastern and central Anatolia. High VP/Vs ratio measurements (>1.85) in western Anatolia may be indicative of partial melt in the lower crust associated with regional extension. [ABSTRACT FROM AUTHOR]

Terrorist attacks on transportation networks have traumatized modern societies. With a single blast, it has become possible to paralyze airline traffic, electric power supply, ground transportation or Internet communication. How and at which cost can one restructure the network such that it will become more robust against a malicious attack? We introduce a new measure for robustness and use it to devise a method to mitigate economically and efficiently this risk. We demonstrate its efficiency on the European electricity system and on the Internet as well as on complex networks models. We show that with small changes in the network structure (low cost) the robustness of diverse networks can be improved dramatically whereas their functionality remains unchanged. Our results are useful not only for improving significantly with low cost the robustness of existing infrastructures but also for designing economically robust network systems. [ABSTRACT FROM AUTHOR]