76 research outputs found

    How Train Transportation Design Challenges can be addressed with Simulation-based Virtual Prototyping for Distributed Systems

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    International audienceThe needs to accelerate development of next generation train control technology, while meeting the quality standards and safety requirements demanded for the development of today's distributed, software dominated, train transportation applications, can only be achieved through a novel methodology that addresses analysis and integration validation of subsystems , via simulation-based virtual prototyping. The methodology must be able to address, much earlier in the development cycle, design goals (among others) such as: • Specifications Validation and Quality of Service Analysis, • Systems safety evaluation and commissioning of automated train control systems, • Early Integration Validation, • Fast assessment of derivative designs, • Compliance with transportation standards (EN50128-SIL2). Such methods actually used in some current projects can be seen as exemplary; they are paving the way for other transportation industry domains to adopt in confidence new system design paradigm shifts

    a multi scalar approach to long term dynamics spatial relations and economic networks of roman secondary settlements in italy and the ombrone valley system southern tuscany towards a model

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    In Roman landscapes, the particular sites defined as secondary settlements (also known as vici/villages, minor centres, agglomerations secondaires and/or stationes/mansiones) have played an 'intermediary' role between the cities and other rural structures (villae/farms), linked to medium- and long-distance economic and commercial trajectories. The aim of this paper is to apply a multi-scalar approach to model their long-term spatial relationships and connectivity with the Mediterranean exchange network. On the macro-scale, we have analysed a sample of 219 reviewed sites to understand the diachronic trends and spatial dynamics of attraction/proximity to significant elements of the landscape such as towns, roads, rivers and coastline. The Ombrone Valley (Tuscany, Italy) represents a micro-scale case study of a complex system, in which the imported pottery (amphorae, African Red Slip ware, ingobbiata di rosso) found in the vicus/mansio of Santa Cristina in Caio, the Roman villa of La Befa and the town of Siena (Saena Iulia) provided diagnostic 'macroeconomic' perspectives. The results show how the secondary settlements occupied a nodal position in the Roman landscape in terms of resilience (long period of occupation until the Early Middle Ages) and spatial organization with a close relationship to natural and anthropic infrastructures and trade functions linked to Mediterranean routes

    Blind identification of FIR MIMO systems driven by cyclostationary inputs in wireless communications using joint block diagonalization

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    The first crystal structure of a thioacylenzyme intermediate in the ALDH family: New coenzyme conformation and relevance to catalysis.

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    Crystal structures of several members of the nonphosphorylating CoA-independent aldehyde dehydrogenase (ALDH) family have shown that the peculiar binding mode of the cofactor to the Rossmann fold results in a conformational flexibility for the nicotinamide moiety of the cofactor. This has been hypothesized to constitute an essential feature of the catalytic mechanism because the conformation of the cofactor required for the acylation step is not appropriate for the deacylation step. In the present study, the structure of a reaction intermediate of the E268A-glyceraldehyde 3-phosphate dehydrogenase (GAPN) from Streptococcus mutans, obtained by soaking the crystals of the enzyme/NADP complex with the natural substrate, is reported. The substrate is bound covalently in the four monomers and presents the geometric characteristics expected for a thioacylenzyme intermediate. Control experiments assessed that reduction of the coenzyme has occurred within the crystal. The structure reveals that reduction of the cofactor upon acylation leads to an extensive motion of the nicotinamide moiety with a flip of the reduced pyridinium ring away from the active site without significant changes of the protein structure. This event positions the reduced nicotinamide moiety in a pocket that likely constitutes the exit door for NADPH. Arguments are provided that the structure reported here constitutes a reasonable picture of the first thioacylenzyme intermediate characterized thus far in the ALDH family and that the position of the reduced nicotinamide moiety observed in GAPN is the one suitable for the deacylation step within all of the nonphosphorylating CoA-independent ALDH family

    Ca-methyl, Ca-n-propylglycine homo-oligomers.

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    Ca-methyl, Ca-n-propylglycine homo-oligomers

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