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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Proposta de metodologia para utilização em hardware reconfigurável para aplicações aeroespaciais / Proposal methodology for use in reprogrammable hardware in aerospace applications

Castellar, Anderson 19 September 2008 (has links)
O programa CBERS é uma parceria entre o governo Brasileiro e o governo Chinês para desenvolvimento de satélites para sensoriamento remoto. A metodologia proposta será aplicada na Câmera Multi Espectral (MUXCAM) dos satélites CBERS-3 e 4, a primeira deste gênero a ser totalmente produzida no Brasil. Devido à alta confiabilidade exigida, principalmente devido ao custo elevado, as aplicações aeroespaciais que envolvem hardware reconfigurável devem possuir uma metodologia de desenvolvimento, desde a definição dos requisitos até o processo de verificação e validação. A utilização da linguagem VHDL e da ferramenta de síntese, processo este chamado de metodologia clássica, produzem um circuito final não otimizado, eliminando redundâncias e alterando a arquitetura proposta. Este trabalho propõe uma metodologia que busca garantir a utilização de uma única arquitetura desde o início do ciclo de desenvolvimento até sua finalização. Esta metodologia torna o processo de desenvolvimento mais confiável e determinístico. / The CBERS program is a partnership between Brazil and China to produce satellites for remote sensing, producing images of the Earth for studies in several areas, mainly the ones related to the sustainable exploitation of natural resourses. The methodology proposed in this work will be applied on the satellite CBERS-3 e 4\'s Multispectral Camera (MUXCAM), the first of its gender fully produced in Brazil. Because the high reliability involved in aerospace applications, a methodology is necessary from software specification until the verification and validation process to guarantee the high reliability. The use of the synthesis tool and VHDL produce a poor circuit, eliminating redundance and making architectural changes. This work proposes a methodology to keep the architectural the same all development cycle, make the development process more trustful for aerospace applications.
102

Proposta de metodologia para utilização em hardware reconfigurável para aplicações aeroespaciais / Proposal methodology for use in reprogrammable hardware in aerospace applications

Anderson Castellar 19 September 2008 (has links)
O programa CBERS é uma parceria entre o governo Brasileiro e o governo Chinês para desenvolvimento de satélites para sensoriamento remoto. A metodologia proposta será aplicada na Câmera Multi Espectral (MUXCAM) dos satélites CBERS-3 e 4, a primeira deste gênero a ser totalmente produzida no Brasil. Devido à alta confiabilidade exigida, principalmente devido ao custo elevado, as aplicações aeroespaciais que envolvem hardware reconfigurável devem possuir uma metodologia de desenvolvimento, desde a definição dos requisitos até o processo de verificação e validação. A utilização da linguagem VHDL e da ferramenta de síntese, processo este chamado de metodologia clássica, produzem um circuito final não otimizado, eliminando redundâncias e alterando a arquitetura proposta. Este trabalho propõe uma metodologia que busca garantir a utilização de uma única arquitetura desde o início do ciclo de desenvolvimento até sua finalização. Esta metodologia torna o processo de desenvolvimento mais confiável e determinístico. / The CBERS program is a partnership between Brazil and China to produce satellites for remote sensing, producing images of the Earth for studies in several areas, mainly the ones related to the sustainable exploitation of natural resourses. The methodology proposed in this work will be applied on the satellite CBERS-3 e 4\'s Multispectral Camera (MUXCAM), the first of its gender fully produced in Brazil. Because the high reliability involved in aerospace applications, a methodology is necessary from software specification until the verification and validation process to guarantee the high reliability. The use of the synthesis tool and VHDL produce a poor circuit, eliminating redundance and making architectural changes. This work proposes a methodology to keep the architectural the same all development cycle, make the development process more trustful for aerospace applications.
103

Problematika testování a verifikace softwaru pro leteckou techniku / Methods of Software Testing and Verification for Airborne Systems

Mačišák, Lukáš January 2011 (has links)
This Master's Thesis describes methods of software certification and development of airborne systems, focusing on software testing and verification during project's life cycle. Thesis includes also designed software verification plan for concrete application according to RTCA/DO-178B. Another part of thesis illustrates the exemplary realization of tests according to designed verification plan. At the close we describe the options of applying the designed verification plan and evaluation of its results.
104

Modèles d'automates d'arbres étendus pour la vérification de systèmes infinis

Jacquemard, Florent 10 November 2011 (has links) (PDF)
Ce document présente l'étude de plusieurs modèles de machines à états finis qui étendent tous le même formalisme: les automates d'arbres classiques, et leur application dans différentes tâches telles que l'analyse statique de programmes ou de systèmes, la typage, la vérification de la cohérence de spécifications, le model checking... Les arbres sont une structure naturelle de données, très répandue en informatique, par exemple pour la représentation des structures de données hiérarchiques ou imbriquées, pour des algorithmes spécifiques (arbres binaires de recherche, algorithmes distribués), comme modèle abstrait pour des données semi-structurées utilisées pour l'échange d'information dans le Web, pour une présentation algébrique de processus récursifs, comme les termes en logique... Lorsqu'il s'agit de raisonner sur des systèmes manipulant des arbres, ou modelisés par des arbres, il est crucial d'avoir une représentation finie d'ensembles infinis d'arbres. Les automates d'arbres sont des machines à états finis permettant une telle représentation. Ils ont fait la preuve de leur adéquation à des tâches de raisonnement: ils ont un modèle théorique bien établi, en étroite relation avec la logique, ils bénéficient de bonnes propriétés de composition et d'algorithmes de décision efficaces. En particulier, les automates d'arbres sont utilisées au coeur de systèmes de vérification formelle d'outils de déduction automatique. Toutefois, les automates d'arbres ont des limitations sévères en expressivité. Par exemple, ils sont incapables de faire du filtrage non-linéaire ou d'exprimer des contraintes d'intégrité tels que les clés dans les bases de données. Certaines extensions ont été proposées afin d'améliorer le modèle en essayant de conserver de bonnes propriétés. Nous présentons dans ce document de plusieurs de telles extensions, leurs propriétés et leur utilisation en vérification symbolique de systèmes et de programmes.
105

Rule-Based Software Verification and Correction

Ballis, Demis 07 May 2008 (has links)
The increasing complexity of software systems has led to the development of sophisticated formal Methodologies for verifying and correcting data and programs. In general, establishing whether a program behaves correctly w.r.t. the original programmer s intention or checking the consistency and the correctness of a large set of data are not trivial tasks as witnessed by many case studies which occur in the literature. In this dissertation, we face two challenging problems of verification and correction. Specifically, verification and correction of declarative programs, and the verification and correction of Web sites (i.e. large collections of semistructured data). Firstly, we propose a general correction scheme for automatically correcting declarative, rule-based programs which exploits a combination of bottom-up as well as topdown inductive learning techniques. Our hybrid hodology is able to infer program corrections that are hard, or even impossible, to obtain with a simpler,automatic top-down or bottom-up learner. Moreover, the scheme will be also particularized to some well-known declarative programming paradigm: that is, the functional logic and the functional programming paradigm. Secondly, we formalize a framework for the automated verification of Web sites which can be used to specify integrity conditions for a given Web site, and then automatically check whether these conditions are fulfilled. We provide a rule-based, formal specification language which allows us to define syntactic as well as semantic properties of the Web site. Then, we formalize a verification technique which detects both incorrect/forbidden patterns as well as lack of information, that is, incomplete/missing Web pages. Useful information is gathered during the verification process which can be used to repair the Web site. So, after a verification phase, one can also infer semi-automatically some possible corrections in order to fix theWeb site. The methodology is based on a novel rewrit / Ballis, D. (2005). Rule-Based Software Verification and Correction [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1948 / Palancia
106

Reducing turbulence- and transition-driven uncertainty in aerothermodynamic heating predictions for blunt-bodied reentry vehicles

Ulerich, Rhys David 24 October 2014 (has links)
Turbulent boundary layers approximating those found on the NASA Orion Multi-Purpose Crew Vehicle (MPCV) thermal protection system during atmospheric reentry from the International Space Station have been studied by direct numerical simulation, with the ultimate goal of reducing aerothermodynamic heating prediction uncertainty. Simulations were performed using a new, well-verified, openly available Fourier/B-spline pseudospectral code called Suzerain equipped with a ``slow growth'' spatiotemporal homogenization approximation recently developed by Topalian et al. A first study aimed to reduce turbulence-driven heating prediction uncertainty by providing high-quality data suitable for calibrating Reynolds-averaged Navier--Stokes turbulence models to address the atypical boundary layer characteristics found in such reentry problems. The two data sets generated were Ma[approximate symbol] 0.9 and 1.15 homogenized boundary layers possessing Re[subscript theta, approximate symbol] 382 and 531, respectively. Edge-to-wall temperature ratios, T[subscript e]/T[subscript w], were close to 4.15 and wall blowing velocities, v[subscript w, superscript plus symbol]= v[subscript w]/u[subscript tau], were about 8 x 10-3 . The favorable pressure gradients had Pohlhausen parameters between 25 and 42. Skin frictions coefficients around 6 x10-3 and Nusselt numbers under 22 were observed. Near-wall vorticity fluctuations show qualitatively different profiles than observed by Spalart (J. Fluid Mech. 187 (1988)) or Guarini et al. (J. Fluid Mech. 414 (2000)). Small or negative displacement effects are evident. Uncertainty estimates and Favre-averaged equation budgets are provided. A second study aimed to reduce transition-driven uncertainty by determining where on the thermal protection system surface the boundary layer could sustain turbulence. Local boundary layer conditions were extracted from a laminar flow solution over the MPCV which included the bow shock, aerothermochemistry, heat shield surface curvature, and ablation. That information, as a function of leeward distance from the stagnation point, was approximated by Re[subscript theta], Ma[subscript e], [mathematical equation], v[subscript w, superscript plus sign], and T[subscript e]/T[subscript w] along with perfect gas assumptions. Homogenized turbulent boundary layers were initialized at those local conditions and evolved until either stationarity, implying the conditions could sustain turbulence, or relaminarization, implying the conditions could not. Fully turbulent fields relaminarized subject to conditions 4.134 m and 3.199 m leeward of the stagnation point. However, different initial conditions produced long-lived fluctuations at leeward position 2.299 m. Locations more than 1.389 m leeward of the stagnation point are predicted to sustain turbulence in this scenario. / text

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