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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.
31

Model systému automatického řízení přesného přiblížení a přistání civilního dopravního letadla za použití informací DGNSS / A model of a civil Atransport Aircraft Automatic Precise Approach & Landing Control System using DGNSS Information

Hvězda, Michal January 2021 (has links)
LPV approaches are being published in the Czech Republic nowadays. Their usage is enabled by the EGNOS European satellite augmentation system. However, published decision heights do not allow equivalence with the ILS CAT I precision approach yet. This work presents the model of automated control of aircraft precision approach. Verification of its functionality shows that applicable airspace requirements can be fulfilled for lower values of decision heights than values already published. The model is developed using contemporary methods of model-based development in the tool supporting common processing of both continuous and discrete signals. Although model architecture follows the structure of commonly used ILS system in definition of coordinate system and in establishing control in two separate directions it allows curved approach. Usage of digital navigation data provided by satellite system opens further opportunities in its usage, expansion and improvements. Model functionality in control of flight course, position and height control is verified in the scenarios covering detailed thesis goals. The goals were defined based on definition of precision approach process and include navigation signal drop-out, impact of wind, various flight path angles and curved approach. Analysis of behavior of controlled aircraft dynamics was a stimulator for research of specific system modules up to the application level, i.e. specific simulations of successful precision approaches.
32

The use of a holistic machine simulation for the development of hydraulic hybrid modules to reduce transient engine-out emissions

Brinkschulte, Lars, Pult, Felix, Geimer, Marcus 25 June 2020 (has links)
In contrast to constant operating states, particle and NOx emissions of internal combustion engines are significantly higher during transient operating states, which occur repeatedly at working cycles of mobile machines. This paper therefore deals with the conception, development and testing of hydraulic hybrid systems to reduce these emissions by phlegmatization of the engine. A wheel loader with its machine-typical working cycle serves as an example for the investigation of the benefits of such a system. Therefore, model based development techniques are used. In a holistic machine simulation, four different typical wheel loader cycles were carried out and the optimum size of the hydraulic accumulator for the hybrid system is identified by a parameter variation. The lowest emitted emissions and the smallest construction dimensions are the key elements for the accumulator selection. With an optimal hydraulic accumulator, a reduction in particle emissions of up to 29.4 % is achieved in one of the cycles investigated.
33

Gerência de Interfaces para Sistemas de Informação: uma abordagem baseada em modelos / Interfaces Management to Information Systems: an models based approach

SILVA, Wilane Carlos da 16 April 2010 (has links)
Made available in DSpace on 2014-07-29T14:57:53Z (GMT). No. of bitstreams: 1 wilane_mestrado.pdf: 4461079 bytes, checksum: da62fa9aebf506f095f41942a579aecc (MD5) Previous issue date: 2010-04-16 / Building and maintaining a Graphical User Interface (GUI) for Enterprise Information Systems usually requires much Software Engineering staff time and effort. This paper describes a model-driven approach to create dynamically and manage these GUIs. In this approach, the Software Engineer designs conceptual models of the information system using object-oriented meta-models. A set of predefined mapping rules is applied to automatically transform and refine the conceptual models in order to generate, in runtime, the look and feel of the GUI, without source code creation. This improves the software usability, assuring consistency and homogeneity of the GUI, increases the productivity of the software engineering staff and simplifies maintenance. In our experiments we have observed an average productivity fifteen times higher than traditional methods of GUI development. / Construir e manter uma Interface Gráfica com Usuário (GUI) para Sistemas de Informação (SI) demanda muito tempo e esforço da equipe de Engenharia de Software. Esta dissertação descreve uma abordagem dirigida por modelos para criar dinamicamente e gerenciar essas interfaces. Nessa abordagem, o Engenheiro de Software projeta um modelo conceitual do sistema de informação usando um meta-modelo orientado a objetos. Um conjunto de regras de mapeamento predefinidas é aplicado para refinar e transformar o modelo conceitual do SI, gerando, em tempo de execução, a sua interface gráfica, com aparência e comportamentos específicos. Esse mecanismo melhora a usabilidade do software, assegurando consistência e homogeneidade das GUIs, aumenta a produtividade da equipe de Engenharia de Software e simplifica a manutenção do SI. Nos experimentos realizados foi observada uma média de produtividade quinze vezes maior do que os métodos tradicionais no desenvolvimento de GUIs.
34

Methodology for a Model-based Timing Analysis Process for Automotive Systems / Méthodologie pour un processus d’analyse temporelle dirigé par les modèles pour les systèmes automobiles

Rekik, Saoussen 09 November 2011 (has links)
Aujourd'hui, les applications automobiles sont devenues de plus en plus complexes avec des ressources limitées et plus de contraintes de temps et de safety. La vérification temporelle est effectuée très tard aujourd'hui au cours du processus de développement automobile (après l'implémentation et au cours de la phase d'intégration). Pour apporter des solutions aux problèmes du développement logiciel automobile, plusieurs approches de développement dirigé par les modèles ont été définit. Ces approches donnent des langages, des concepts et des méthodologies pour la description de l'architecture des systèmes automobiles. Cependant, ces approches ne donnent aucun guide méthodologique pour intégrer l'analyse temporelle (notamment l'analyse d'ordonnancement) tout au long du processus de développement. Ce travail de thèse propose de développer une méthodologie décrivant un processus d'analyse temporelle dirigé par les modèles. Cette méthodologie décrit les différentes phases du processus de développement dirigé par les modèles et comment l'analyse temporelle est effectuée durant chaque phase. / Automotive systems are characterized today by increasing complexity, limited resources and more and more timing and safety requirements. Timing verification is performed too late during the development process. It is addressed by means of measurements and tests rather than through formal and systematic analysis. To meet the challenges of automotive software development, many model-based approaches have been developed. These approaches give modeling languages, concepts and methodologies allowing the description of automotive architecture. However, these approaches give no guidance for the integration of timing analysis (mainly scheduling analysis) during the phases of the model-based development process. This PhD work aims at defining a methodology that describes a model-based timing analysis process. This methodology describes the different phases of the model-based development process and how timing analysis is performed during each phase. This work has been performed in the context of a technical collaboration between Continental Automotive and the CEA laboratory.
35

TraceME: Traceability-based Method for Conceptual Model Evolution

Ruiz Carmona, Luz Marcela 23 May 2016 (has links)
[EN] Renewing software systems is one of the most cost-effective ways to protect software investment, which saves time, money and ensures uninterrupted access to technical support and product upgrades. There are several motivations to promote investment and scientific effort for specifying systems by means of conceptual models and supporting its evolution. In order to contribute to the requirements engineering field with automated software production methods, we design TraceME to cover the spectrum of activities from requirements to code focusing on organisational evolution. In this sense, the spectrum of activities involves various information system perspectives of analysis that need to be integrated. In this complex setting, traceability and conceptual models are key concepts. Mechanisms to trace software specifications from requirements to code are important to justify evolution processes; versions of information systems should be traced in order to get the connection between old and new specifications. Moreover, it is necessary to find mechanisms to facilitate change specifications, measurement, and interpretation. To design this thesis we follow Design Science by Roel Wieringa. Design Science gives us the hints on how to conduct the research, be rigorous, and put in practice scientific rules. Besides Design Science has been a key factor for structuring our research, we acknowledge the application of this framework since it has helps us to report clearly our findings. We build TraceME by making a method engineering effort, which shapes its fragmented nature in chunks. The architecture of TraceME opens a wide window of opportunities for its application in real world situations. To facilitate industrial adoption, we develop open source tools to support the implementation of the TraceME chunks. For example, one case study and one action-research protocols have been executed in two different organisations in Spain. The validation of TraceME has taken place in laboratory demonstrations, controlled experiments, action research and case study experiences in industry. Thanks to the validations various lessons learnt have been gathered and greatly influenced the maturity of the method. For example: the importance to consider end-users' perceptions for discovering needs to mitigate, and the significance to get knowledge from the application of TraceME in different contexts. The evidences from the validations demonstrate that TraceME is feasible to be applied to support evolution projects. In addition, future research is needed for promoting the implementation of TraceME. We envision short term and future-term work that motivate us to tackle the challenge to support evolution projects. / [ES] La evolución de sistemas software es una de las actividades mas importantes que permiten minimizar el tiempo de puesta en producción de actualizaciones y nuevos desarrollos, reducir los costos que implica desarrollar una aplicación desde cero, y además asegura el acceso ininterrumpido de servicios. Existen variadas motivaciones para promover la investigación y desarrollo de soluciones para especificar y evolucionar sistemas de información mediante modelos conceptuales. Para contribuir al campo de la ingeniería de requisitos con métodos automáticos de producción de software, hemos diseñado el método TraceME para cubrir el espectro de actividades desde requisitos a código con un enfoque de evolución organizacional. De este modo, el espectro de actividades involucra diferentes perspectivas de análisis de sistemas de información que necesitan ser integradas. En este escenario tan complejo, la trazabilidad y los modelos conceptuales son conceptos clave. Es necesario disponer de mecanismos para trazar especificaciones de software desde requisitos a código con el fin de justificar procesos de evolución. Las versiones de los sistemas de información deben ser trazables con el fin de establecer la conexión entre especificaciones obsoletas y actuales. Adicionalmente, es necesario encontrar mecanismos para facilitar la especificación del cambio, su medición e interpretación. Para diseñar esta tesis hemos seguido el marco de Design Science de Roel Wieringa. Design Science nos ha proporcionado las claves para conducir esta investigación, ser rigurosos y poner en práctica reglas científicas. Además de que Design Science ha sido un factor clave para estructurar nuestra investigación, reconocemos que la aplicación de este marco nos ha ayudado a reportar claramente nuestros hallazgos. Hemos aplicado ingeniería de métodos para diseñar y construir TraceME. Gracias a esto, la naturaleza de TraceME es conformada mediante fragmentos de método. La arquitectura de TraceME abre una amplia ventana de oportunidades para su aplicación en situaciones de la vida real. Para facilitar la adopción industrial de TraceME, hemos desarrollado herramientas de software libre para dar soporte a los fragmentos de TraceME. Por ejemplo, un caso de estudio y una experiencia de action research han sido ejecutadas en dos organizaciones en España. La validación de TraceME ha sido llevada a cabo mediante demostraciones de laboratorio, experimentos controlados, un caso de estudio y una experiencia de action research en industria. Como resultado, TraceME ha sido mejorado considerablemente; además hemos descubierto investigaciones a realizar a corto, mediano y largo plazo con el fin de implementar TraceME en la industria. Las evidencias obtenidas como resultado de las validaciones demuestra la factibilidad de TraceME para ser aplicado en proyectos de evolución organizacional. El trabajo futuro nos motiva a afrontar los retos que conlleva el soporte de proyectos de evolución de sistemas de información. / [CAT] L'evolució dels sistemes programari és una de les activitats més importants que permeten minimitzar el temps de posada en producció d'actualitzacions i nous desenvolupaments, reduir els costos que involucra desenvolupar una aplicació des de cero, a més d' assegurar l'accés ininterromput de serveis. Existixen diverses motivacions per promoure la investigació i desenvolupament de solucions per a especificar i evolucionar sistemes de informació mitjançant models conceptuals. Per tal de contribuir al camp de l'enginyeria de requisits amb mètodes automàtics de producció de programari, hem dissenyat el mètode TraceME per cobrir l'espectre d'activitats des de requisits a codi en un enfocament d'evolució organitzacional. Així, l'espectre d'activitats involucra diferents perspectives d'anàlisi de sistemes d'informació que necessiten ser integrades. En aquest escenari tan complex, la traçabilitat i els models conceptuals són conceptes clau. És necessari disposar de mecanismes per traçar especificacions de programari des de requisits a codi amb la fi de justificar processos d'evolució. Les versions dels sistemes d'informació deuen ser traçables amb la fi d'establir la connexió entre especificacions obsoletes i actuals. Addicionalment, és necessari trobar mecanismes per facilitar l'especificació del canvi, la seua mesura i interpretació. Per tal de dissenyar aquesta tesi, hem seguit el marc de Design Science de Roel Wieringa. Design Science ens ha proporcionat les claus per conduir aquesta investigació, ser rigorosos i posar en pràctica regles científiques. A més a més, Design Science ha sigut un factor clau per estructurar la nostra investigació, reconeixem que l'aplicació de aquest marc ens a ajudat a reportar clarament els nostres resultats. Hem aplicat enginyeria de mètodes per dissenyar i construir TraceME. Gràcies a açò, la natura de TraceME es conforma mitjançant fragments de mètodes. L'arquitectura de TraceME obri una ampla finestra d'oportunitats per a la seua aplicació en situacions de la vida real. Per facilitar l'adopció industrial de TraceME, hem desenvolupat ferramentes de programari lliure per tal de donar suport als fragments de TraceME. Per exemple, un cas d'estudi i una experiència de action research han sigut executades en dos organitzacions a Espanya. La validació de TraceME ha sigut portada a cap mitjançant demostracions de laboratori, experiments controlats , un cas d'estudi i una experiència de action research en l'industria. Com a resultat, TraceME ha sigut millorada considerablement; a més a més, hem descobert investigacions a realitzar a curt, mig i llarg termini amb la fi d'implementar TraceME a l'industria. Les evidències obtingudes com a resultat de les validacions, demostren la factibilitat de TraceME per ser aplicat en projectes d'evolució organitzacional. El treball futur presenta nous reptes que ens motiven a afrontar el suport de projectes d'evolució de sistemes d'informació. / Ruiz Carmona, LM. (2016). TraceME: Traceability-based Method for Conceptual Model Evolution [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/64553 / TESIS
36

Metody technické prognostiky aplikovatelné v embedded systémech / Methods of Technical Prognostics Applicable to Embedded Systems

Krupa, Miroslav January 2012 (has links)
Hlavní cílem dizertace je poskytnutí uceleného pohledu na problematiku technické prognostiky, která nachází uplatnění v tzv. prediktivní údržbě založené na trvalém monitorování zařízení a odhadu úrovně degradace systému či jeho zbývající životnosti a to zejména v oblasti komplexních zařízení a strojů. V současnosti je technická diagnostika poměrně dobře zmapovaná a reálně nasazená na rozdíl od technické prognostiky, která je stále rozvíjejícím se oborem, který ovšem postrádá větší množství reálných aplikaci a navíc ne všechny metody jsou dostatečně přesné a aplikovatelné pro embedded systémy. Dizertační práce přináší přehled základních metod použitelných pro účely predikce zbývající užitné životnosti, jsou zde popsány metriky pomocí, kterých je možné jednotlivé přístupy porovnávat ať už z pohledu přesnosti, ale také i z pohledu výpočetní náročnosti. Jedno z dizertačních jader tvoří doporučení a postup pro výběr vhodné prognostické metody s ohledem na prognostická kritéria. Dalším dizertačním jádrem je představení tzv. částicového filtrovaní (particle filtering) vhodné pro model-based prognostiku s ověřením jejich implementace a porovnáním. Hlavní dizertační jádro reprezentuje případovou studii pro velmi aktuální téma prognostiky Li-Ion baterii s ohledem na trvalé monitorování. Případová studie demonstruje proces prognostiky založené na modelu a srovnává možné přístupy jednak pro odhad doby před vybitím baterie, ale také sleduje možné vlivy na degradaci baterie. Součástí práce je základní ověření modelu Li-Ion baterie a návrh prognostického procesu.
37

Development of a Cost-Effective, Reliable and Versatile Monitoring System for Solar Power Installations in Developing Countries : A Minor Field Study as a Master Thesis of the Master Programme in Engineering Physics, Electrical Engineering

Trella, Fredrik, Paakkonen, Nils January 2016 (has links)
This report is the result of a conducted Minor Field Study (MFS), to the greatestextent funded by the Swedish International Development Cooperation Agency(SIDA), in an attempt to design a system for evaluating smaller solar power systems indeveloping countries. The study was to the greater part conducted in Nairobi, Kenyain close collaboration with the University of Nairobi. The aim was to develop asystem that would use easily available components and keep the costs to a minimum,yet deliver adequate performance. The system would measure certain parameters of asolar power system and also relevant environmental data in order to evaluate theperformance of the system. Due to the specific competence of the collaboratinggroup at the University of Nairobi, a Kinetis Freescale K64-microcontroller with anARM-Cortex processor was selected as the core of the design. Components wereselected, schematics were drawn, a circuit board was designed and manufactured andsoftware was written. After 12 weeks a somewhat satisfying proof-of-concept wasreached at the end of the field study in Kenya. The project however proved howdifficult it is to go from first idea to a functional proof-of-concept during a limitedtimeframe, and also in an East-African country. The final proof-of-concept was testedat Mpala Research Centre in Kenya and despite containing some flaws proved that itwould indeed be possible to design a working system on the principles discussed inthis report. The system is open-source, so anyone may use and modify it.

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