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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.
1

Le diagnostic de système de systèmes : une approche à base de modèles appliquée aux bancs d’intégration avionique / System of systems diagnosis : a model-based approach for avionics test bench diagnosis

Cossé, Ronan 02 November 2016 (has links)
Le but de cette thèse est d’étudier le diagnostic de systèmes de test utilisés en aéronautique chez AIRBUS HELICOPTERS, appelés bancs d’intégration avioniques.Les hélicoptères embarquent une vingtaine de fonctionnalités pour offrir aux clientsd’hélicoptère les fonctions qui vont lui permettre d’opérer son appareil dans toutes lesconditions de vol (visibilité réduite, accès restreint, terrain hostile, en zone de combat). Les tests d’intégration permettent de valider le système embarqué par rapport à un ensemble d’exigences définies par les autorités de certification européenne et américaine. Ils consistent à évaluer l’état des sous-systèmes avioniques au sein du système global, c’est-à-dire à l’aide de simulation de l’environnement réel de l’hélicoptère. Chez AIRBUS HELICOPTERS, pour diminuer le coût des tests réalisés sur l’hélicoptère, des tests préliminaires dans un environnement simulé, appelé banc d’intégration, sont effectués. Le banc d’intégration doit être compatible avec les différentes configurations de l’hélicoptère et les simulations de son environnement. Nous nous intéressons dans cette thèse au diagnostic du banc d’intégration avionique. La mise en œuvre de méthodes de diagnostic est indispensable pour identifier les causes de défaillances du banc d’intégration. Nous avons travaillé sur un modèle de diagnostic adapté au banc d’intégration. Les notions de diagnostic fonctionnel et structurel ont été définies et ont servi à la mise en place d’un algorithme de diagnostic. Nous avons ainsi défini des fonctions de vérification que nous avons intégrées au banc de test afin de valider notre méthode. / The aim of this thesis is to study the diagnostic of test systems used at Airbus HELICOPTERS called avionics test benches. Helicopters embark twenty features to offer helicopter customers functions that will enable to operate the aircraft in all flight conditions (reduced visibility, restricted area, hostile terrain, in a combat zone). Integration tests are used to validate the embedded system with regards to a set of requirements defined by the European and US certification authorities. The state of avionics subsystems is assessed within the overall system, that is to say, using simulation of the real environment of the helicopter. AIRBUS HELICOPTERS wants to reduce the cost of the tests of the helicopter, preliminary testing in a simulated environment, called integration benches. The integration bench must be compliant with the various configurations of the helicopter and simulation environment.We are interested in this thesis in the diagnosis of avionics integration bench. The implementation of diagnostic methods is essential to identify the causes of failures of integration benches. We work on a diagnostic model adapted to the integration bench. functional and structural diagnostic concepts were defined and used for the establishment of a diagnostic algorithm. We have defined verfications functions we have integrate on test benches to validate our method.
2

A Framework for Complex Product Architecture Analysis using an Integrated Approach

Uddin, Amad, Khan, M. Khurshid, Campean, Felician, Masood, M. 12 May 2016 (has links)
Yes / Contemporary design decomposition and synthesis analytical tasks at the conceptual design stage reply on functional and structural modelling approaches. There is a wide diversity of elements used by various modelling approaches for information and representation of product architecture, which incurs difficulties for multidisciplinary engineers working across different phases of design in capturing, visualising, sharing and tracing consistent yet common knowledge and elements across the function and structure domains. This prompts for fixation of detail and common modelling knowledge across both functional and structural analytical approaches which is also critical from automatized software perspective. A limitation of existing approaches is that they tend to focus more on ‘what’ and less on ‘how’ (and vice versa). This paper proposes an integrated conceptual product architecting approach that combines and expands the functional and structural modelling approaches, enabling capturing and tracing knowledge coherently through a common binding domain. This is underpinned by the view that most interaction requirements amongst the physical components during structural modelling can be derived from functional modelling. The proposed integrated approach is underpinned by the critical analysis and synthesis of existing approaches in literature dealing with functional and structural architecture analysis, integrated within a Multiple Domain Matrix (MDM) to fuse the knowledge of both solution independent (functional) and dependent (structural) analyses. The proposed framework is illustrated with a case study of solar robot toy, followed by discussion and suggestions for future work.
3

The Use of Function Modelling Methods in Industry: Insights from a Large Scale Study with an Automotive OEM

Yildirim, Unal, Campean, Felician, Uddin, Amad 29 May 2022 (has links)
Yes / This paper presents an evaluation study for the System State Flow Diagram function modeling framework based on a large-scale study with an automotive OEM. Technical reports are used to evaluate the usage of the framework within the organization. The paper also introduces a list of the type of problems that engineers are interested in in practical function modelling. The findings suggest that there is a widespread uptake of the framework across the organization and it supports the usage of relevant key engineering tools within the context of a broader model-based Failure Mode Analysis methodology.
4

Bivariate relationship modelling on bounded spaces with application to the estimation of forest foliage cover by Landsat satellite ETM-plus sensor

Moffiet, Trevor Noel January 2008 (has links)
Research Doctorate - Doctor of Philosophy (PhD) / Due to the effects of global warming and climate change there is currently intense and growing international interest in suitable modelling methods for relating satellite remotely sensed spectral imagery of vegetated landscapes to the biophysical structural variables in those landscapes across regional, continental or global scales. Of particular interest here is the satellite optical remote sensing of forest foliage cover—measured as foliage projective cover (FPC)—by Landsat ETM+ (Enhanced Thematic Mapper plus) sensor. In the remote sensing literature, different empirical and physical modelling approaches exist for relating remotely sensed imagery to the landscape parameters of interest, each with their own advantages and disadvantages. These approaches, in the main, may be broadly categorised as belonging to one, or a combination of: spectral mixture analysis (SMA) modelling, canopy reflectance modelling, multiple regression (MR) modelling or, spectral vegetation index (SVI) modelling. This thesis uses the SVI approach, partly in comparison to the MR approach. Both the SVI and MR approaches require field-based data to establish the relationship between the biophysical parameter and the spectral index or spectral responses within defined spectral bandwidths. Surrogate measures of the biophysical parameter are sometimes used extensively to establish this relationship and therefore a separate calibration relationship is required.This has inherent problems when the output of one model is substituted into the next and the effects of carry-over of error from one model to the next are not considered. My main goal is therefore to develop a modelling approach that will allow a larger set of one or more surrogate measures to be combined with a smaller set of ‘true’ measures of the biophysical parameter into the one model for establishing the relationship with the SVI and hence the spectral imagery. Success in meeting the goal is the illustration of a working model using real data. In progression towards meeting the goal, two new modelling ideas are developed and synthesised into the creation of an overall modelling framework for estimating FPC from spectral imagery. The modelling framework, which has potential for use in other applications, allows for the incorporation of different types of data including different calibration relationships between variables while avoiding the usual, stepwise approach to the linking of separate relationship models and their variables. One contribution that is new to both remote sensing and statistical modelling practices involves a polar transformation of the principal components of a multi-spectral image of a local reference landscape to produce a set of empirically based, invariant three-dimensional spectral index transformations that have potential for application to the spectral images of different regional landscapes and possibly global landscapes. In particular, the vegetation index from the set has approximate bounded properties that we exploit for modelling of its contribution to residual variation in its relationships with the biophysical variables measured on the ground. The other contribution to statistical modelling practice that has potential for application by a wide range of disciplines is the direct modelling of interdependent relationships between pairs of bounded variates, each considered to have a measurement error structure that can be modelled as though it is similar to sampling variation. Associated with this particular contribution is the development of novel geometric methods to construct approximate prediction bounds and to assist with model interpretations.
5

Optimisation énergétique d'un véhicule hybride / Optimisation énergétique d'un véhicule hybride

Mokukcu, Mert 05 October 2018 (has links)
Les progrès technologiques augmentent la complexité des systèmes énergétiques, ce qui permet d'avoir variés sources et architectures possibles. Si le contexte économique et écologique est également pris en compte, l'industrie automobile est menée à aligner sa production sur des véhicules hybrides ou électriques qui disposent d'une gestion de l'énergie sophistiquée. Ainsi, les études pour la conception sont orientées à l'optimisation et à la gestion de l'énergie en tenant compte les tendances des constructeurs : i) augmenter les performances des véhicules, ii) avoir des véhicules moins polluants en réduisant la consommation de carburant et iii) diminuer le temps nécessaire à la conception et au processus de validation. Face à ces problèmes, une approche qui aide le concepteur à caractériser le système de gestion de l'énergie d'un VEH est proposée. Cette caractérisation consiste à : i) choisir l'architecture de la chaîne de traction, ii) le dimensionnement des composants (groupes) et iii) le contrôleur de gestion de l'énergie. Pour accomplir ces tâches, une méthode de modélisation énergétique fonctionnelle est proposée. Cette approche proposée à un niveau d'abstraction "juste nécessaire" qui permet d'avoir une analyse énergétique pour une série de cas d'utilisation. La méthode repose sur des boucles de contrôle locales, un contrôleur global et des équations de base et elle permet d'avoir une optimisation modulaire pour tout changement d'architecture. Prochaine étape de la validation est l'adaptation du modèle fonctionnel afin d'obtenir le contrôleur de haut niveau pour le niveau multi-physique avec deux étapes proposées : i) l'ajustement des paramètres des éléments fonctionnels et ii) l'interconnexion les modèles fonctionnels et multi-physiques. Après l'illustration du démonstrateur d'un VEH, trois stratégies de gestion de l'énergie sont proposées : i) fondée sur des règles, ii) fondée sur PFC avec fonctionnement de partage de besoin par priorisation et iii) fondée sur PFC avec fonctionnement boost. Les stratégies de gestion de l'énergie proposées sont ensuite comparées par indicateurs de performance (consommation de carburant, nombre de cycles marche/arrêt du groupe motopropulseur et consommation de carburant corrigée avec variation de l'état de charge du stockage électrique) avec des cas d'usages définis. / Technology advancements increase the complexity of energy systems which bring additional varieties of sources and possible architectures to choose. If the economic and ecological context is also included, the automobile industry is in_uenced to align their production to hybrid or battery electric vehicles that have sophisticated energy management system. Thus, researchers and designers have oriented their studies for system design, optimisation and energy management that take into consideration the constructor tendencies : i) increasing vehicle performances, ii) having less polluting vehicles by reducing fuel consumption and iii) decreasing the time needed for design and validation process. Against these problematics, an approach that assists the system designer to fully characterize the energy management system of a HEV is proposed. This characterization consists : i) choosing powertrain architecture, ii) component (units) sizing and iii) energy management controller. In order to accomplish these tasks, a functional energetic modelling method is proposed. Proposed functional modelling level has a level of abstraction _just necessary_ which permits to have energetic analysis for a series of use case. This method relies on local control loops, a global controller and basic equations and it allows to have a modular optimisation for any architecture changes. The second-stage in the validation is completed by adapting the functional model in order to obtain the high-level controller for the multi-physical level with two offered steps : i) adjustment the functional elements' parameters and ii) interconnection the functional and multi-physical models. After the illustration of the demonstrator of a HEV, three strategies for energy management is proposed : i) based on rules, ii) based on PFC with power sharing function and iii) based on PFC with booster function. The proposed energy management strategies then compared by performance indicators (fuel consumption, number of on/off cycles of engine powertrain and corrected fuel consumption with variation of state of charge of electrical storage) with defined use cases.

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