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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.
81

Regulering og optimalisering av Shell Eco-maraton kjøretøy / Control and optimization of Shell Eco-marathon vehicle

Øverby, Jardar Sølna January 2011 (has links)
Å bygge en bil som kan kjøre tusen kilometer på energien i en eneste liter bensin; er ingeniørkunst. Når tusenvis av Europas ypperste studenter innen teknologi og ingeniørvitenskap hvert år møtes i konkurransen Shell Eco-marathon, utfordres skillet mellom hva som oppfattes som mulige og umulige. Kreativitet og respektløs nytenkning utfoldes når morgendagens teknologer får muligheten til å følge nysgjerrigheten på jakt etter nye å bedre teknologiske løsninger for morgendagens samferdsel. Dette er hvordan det har vært å oppleve og være deltager i NTNU sitt fjerde bidrag til Shell Eco-marathon. Motivasjonen for prosjektet har med andre ord vært stor.Arkitekturen og mange av modulene som ble brukt i kontrollsystemet i 2011-versjonen av DNV Fuel Fighter, ble arvet fra 2010-versjonen. Det ble i 2010 lagt ned et solid stykke arbeid i lage et modulbasert og fleksibelt kontrollsystem til bilen. Det lot seg derfor gjøre å kombinere en videreutvikling av noen av fjorårets løsninger, med også å introdusere helt ny funksjonalitet. Hver modul sin videre inndeling i en spesialmodul, og en universalmodul som er lik for alle nodene i det CAN-baserte nettverket har fortsatt fungert utmerket.Av de nyvinningene som faller inn under denne rapporten, nevnes først og fremst arbeidet med utvikling av et hybridsystem for å kunne bruke en modul av superkondensatore til å øke energiutnyttelsen i den elektriske delen av framdriftssystemet. Det er da først og fremst muligheten til å kunne tilbakeføre noe av bevegelsesenergien fra bilen til kondensatorene under nedbremsing med elektromotoren, som har vært det viktigste formålet. Slik kan energien så lagres til videre bruk under påfølgende akselerasjon. Dette systemet er både simulert og produsert, men ble dessverre ikke tatt i bruk under faktiske konkurransen. For senere studenter ligger det flere muligheter her til å få tatt dette systemet ordentlig i bruk.Videre nevnes det hardware-endringer for å bedre kontrollen over vifta som sørger for luftgjennomstrømning i den hydrogenbaserte brenselcella. Dette ga bedre kontroll over arbeidstemperaturen i cella. I tillegg en ny modul for å sikre gode målinger av flere viktige tilstander i systemet lagt til. Det medførte at det for første gang ble gjennomført målinger av strømmen i koblingene mellom brenselcelle og motorkontroller.Årets største utfordring har imidlertid vært motoren. Uforutsette svakheter i designet av motoren, førte til store problemer å komme opp i store nok hastigheter. Årsaken var at en for høy tilbakeindusert spenning fra motoren gjorde at spenningsnivået som var tilgjengelig fra brenselcella ikke strakk til når turtallet vokste. Dette problemet ble ikke beskrevet i noen rapport fra 2010. I samarbeid med SmartMotor, som en av flere viktige partnere for prosjektet, fikk selv denne utfordringen en løsning. Denne løsningen innebar å øke luftgapet i motoren slik at koblingen mellom permanentmagnetene og statorviklingene ble svakere. Dette er imidlertid en løsning som kompromiterer virkningsgraden i motoren. Hvor mye redusert virkningsgrad denne tilpasningen førte til ble aldri forsøkt målt. Ved en eventuell gjenbruk av motoren, må dette problemet få en permanent løsning.Som kronen på verket ble laget til slutt belønnet med to gjeve priser etter et godt gjennomført løp på konkurransens siste dag. Det ble andreplass i klassen, og pris for beste mediehåndtering.
82

Dynamic stability control and human energetics

Ekizos, Antonis 13 November 2018 (has links)
Die Bewegungs-kontrollstrategien kontextabhängig und abhängig von unterschiedlichen Kriterien ausgewählt werden. Einerseits ist die Stabilität in den Bewegungszuständen wie der Fortbewegung ausschlaggebend für die ungestörte Ausführung bestimmter Handlungen und erfordert eine effektive Steuerung durch das zentrale Nervensystem. Andererseits wird die Bewegungsstrategieauswahl durch das zentrale Nervensystem dadurch bestimmt, dass die Energiekosten minimiert werden soll. Beide Konzepte (d.h. die Aufrechterhaltung der Stabilität und die Energiekostenminimierung) spielen eine fundamentale Rolle bei der Frage, warum sich Menschen so bewegen, wie sie es tun. Unklar ist dabei allerdings, auf welche Weise das zentrale Nervensystem beide Prinzipien gegeneinander gewichtet. In den letzten 20 Jahren haben uns wissenschaftliche Konzepte wie die Chaostheorie oder die Theorie komplexer Systeme eine neue Herangehensweise an diese Fragen ermöglicht. Diese Arbeit untersucht die dynamische Stabilität menschlicher Fortbewegung mit Hilfe des Konzepts der Ljapunowanalyse. Als erstes wird eine methodologische Untersuchung der Verlässlichkeit des maximalen Ljapunowexponenten beim Gehen und Laufen durchgeführt (Kapitel 2). Danach wird verglichen zwischen dem Laufen unter normalen Umständen und dem darauffolgenden Laufen ohne Schuhe, wobei letzteres eine Abnahme der Stabilität nach dem Übergang zu den neuen Umständen zur Folge hat (Kapitel 3). In der letzten Untersuchung wurde ein unterschiedlich langes Training zur Verbesserung der Laufenergetik durchgeführt, in einer Gruppe nur über einen kurzen und in einer anderen Gruppe über einen etwas längeren Zeitraum (Kapitel 4). Die Ergebnisse zeigen, dass Bewegungskontrollfehler für die Energiekosten beim Laufen eine Rolle spielen können, und legen somit eine flexible Priorisierung der Bewegungskontrolle nahe. / Motor control strategies are chosen in a context dependent manner, based on different criteria. On the one hand stability in dynamic conditions such as locomotion, is crucial to uninterrupted task execution and requires effective regulation by the central nervous system. On the other, minimization of the energetic cost of transport is instrumental in choosing the locomotion strategy by the central nervous system. Both these concepts, (i.e. maintaining stability and optimization of energetic cost of locomotion) have a fundamental role on how and why humans move in the way they do. However, how the human central nervous system prioritizes between the different goals is unknown. In the last 20 years, ideas from scientific paradigms such as chaos theory and complex systems have given us novel tools to approach these questions. The current thesis examines the dynamic stability during human locomotion under such an approach using the concept of Lyapunov analysis. At first a methodological examination of the reliability of the maximum Lyapunov exponent in walking and running has been conducted (chapter 2). Afterwards, an examination between the habitual running condition and after removal of footwear was conducted, exhibiting a decrease in stability following the acute transition to the new condition (chapter 3). In the last study, a training intervention aiming at improvements in running energetics was performed using a short-term and a long-term intervention group (chapter 4). The results evidence that motor control errors can have a role in the energy cost of running and thus, a flexible prioritization of the motor control output.
83

ANALYSIS AND CONTROL OF COMPRESSOR SYSTEMS VIA NUMERICAL APPROACH / 以數值模擬分析與控制壓縮系統之動態特性

Lee, Win-Chin, 李文欽 January 1996 (has links)
碩士 / 國立交通大學 / 控制工程系 / 84 /
84

MMTS: Multi-Vehicle Metric & Telemetry System

Aspnes, Richard K., Yuma, Russell J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 17-20, 1988 / Riviera Hotel, Las Vegas, Nevada / The Multi-Vehicle Metric & Telemetry System (MMTS) is a complete range system which performs real-time tracking, command destruct, and telemetry processing functions for support of range safety and the test and evaluation of airborne vehicles. As currently configured, the MMTS consists of five hardware and software subsystems with the capability to receive, process, and display tracking data from up to ten range sensors and telemetry data from two instrumented vehicles. During a range operation, the MMTS is employed to collect, process, and display tracking and telemetry data. The instrumentation sites designated for operational support acquire tracking and telemetered data and transmit these data to the MMTS. The raw data is then identified, formatted, time tagged, recorded, processed, and routed for display to mission control and telemetry display areas. Additionally, processed tracking data is transmitted back to instrumentation sites as an aid to acquire or maintain vehicle track. The mission control area consists of a control and status console, high resolution color graphics stations, and large screen displays. As the mission controller observes mission progress on the graphics stations operational decisions can be made and invoked by activation of the appropriate console controls. Visual alarms provided my MMTS will alert mission control personnel of hazardous conditions posed by any tracked vehicle. Manual action can then be taken to activate transmission of the MMTS vehicle destruct signal. The telemetry display area consists of ten fully-functional, PC compatible computers which are switchable to either of two telemetry front end processors. Each PC can be independently set up by telemetry analysts to display data of interest. A total of thirty data pages per PC can be defined and any defined data page can be activated during a mission. A unique feature of the MMTS is that telemetry data can be combined with tracking data for use by the range safety functions.
85

Trajectory Tracking Control of Hamiltonian and Hybrid Control Systems / ハミルトン系とハイブリッド系の軌道追従制御 / ハミルトンケイ ト ハイブリッドケイ ノ キドウ ツイジュウ セイギョ

Sakurama, Kazunori 23 March 2004 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(情報学) / 甲第11003号 / 情博第103号 / 新制||情||25(附属図書館) / UT51-2004-G850 / 京都大学大学院情報学研究科システム科学専攻 / (主査)教授 杉江 俊治, 教授 足立 紀彦, 教授 片山 徹 / 学位規則第4条第1項該当
86

Temporal data, temporal data models, temporal data languages and temporal database systems.

Hom, Donald Dokeung. January 1988 (has links)
No description available.
87

STUDIES ON SINGULAR PERTURBATION MODELLING AND CONTROL OF LARGE-SCALE SYSTEMS / 特異摂動論による大規模系のモデリングと制御に関する研究

Kando, Hisashi 23 January 1987 (has links)
Kyoto University (京都大学) / 0048 / 新制・論文博士 / 工学博士 / 乙第6122号 / 論工博第2004号 / 新制||工||683(附属図書館) / UT51-62-C115 / (主査)教授 西川 褘一, 教授 服部 嘉雄, 教授 若林 二郎 / 学位規則第5条第2項該当
88

Ανάπτυξη μεθόδων αξιολόγησης της τρισδιάστατης κατανομής δόσης στη σύμμορφο ακτινοθεραπεία και ποιοτικός έλεγχος των συστημάτων σχεδιασμού θεραπείας / Development of evaluation methods of the three-dimensional dose distribution in conformal radiation therapy and quality control of treatment planning systems

Πανίτσα, Ευανθία 13 April 2010 (has links)
- / -
89

Flatness, tangent systems and flat outputs

Franch Bullich, Jaume 13 September 1999 (has links)
En esta tesis doctoral se presentan diversos métodos para la linealización de sistemas de control no lineales o para el estudio de la platitud. Se utilizan dos aproximaciones diferentes, en concreto: geometría diferencial y álgebra diferencial.En el marco de álgebra diferencial, se presenta un estudio de los sistemas lineales de control desde la perspectiva de la teoría de módulos. A pesar de que los resultados han sido establecidos previamente por otros autores, algunas demostraciones y ejemplos son originales.Entre las nuevas demostraciones cabe resaltar la que se refiere a la equivalencia entre sistemas de control lineales en representación de variables de estado, y los módulos sobre un anillo de operadores diferenciales. Los resultados de este estudio son ampliamente utilizados en el desarrollo de otros capítulos de la tesis en los que se usa el álgebra diferencial. En este contexto las principales contribuciones son:Una nueva demostración del hecho, bien conocido, que la linealización por realimentación estática y la linealización por realimentación dinámica son equivalentes en el caso de sistemas de entrada simple. Para la linealización de este tipo de sistemas, se desarrolla un nuevo algoritmo.Un procedimiento teórico para linealizar sistemas de entrada múltiple, basado en el cociente de módulos. También se ha hecho un paquete informático para llevar a cabo los cálculos necesarios. Debe mencionarse que este procedimiento es válido para linealizar sistemas mediante realimentación estática, así como para sistemas que sólo puedan linealizarse mediante realimentación dinámica.Una condición para comprobar si las salidas linealizantes encontradas pueden obtenerse mediante prolongaciones. Como aplicación, se muestran algunos ejemplos de sistemas linealizables por prolongaciones. Algunos de estos sistemas se creían que no eran linealizables mediante esta técnica.
90

Contrôle acoustique d'un parc éolien / Acoustic control of wind farms

Dumortier, Baldwin 25 September 2018 (has links)
Actuellement, la construction d’un parc éolien nécessite une étude acoustique qui doit assurer la tranquillité des habitants aux alentours et la conformité au regard de la réglementation en vigueur. Pour ce faire, des mesures acoustiques sont réalisées sur une période d’environ deux semaines. Durant ces mesures, des cycles de marche et d’arrêt des machines sont réalisés afin de mesurer la différence de niveau sonore entre le bruit ambiant (éoliennes en fonctionnement) et le bruit résiduel (éoliennes à l’arrêt). Un plan de bridage des machines est alors calculé et fourni à l’exploitant afin de l’implémenter dans le système de contrôle local des éoliennes (SCADA). Actuellement, ce plan dépend grossièrement des conditions météorologiques et des périodes de la journée, supposées corrélées aux conditions acoustiques. En pratique, cette manière de procéder engendre fréquemment des dépassements du critère réglementaire et/ou des pertes de production électrique. Ceci est dû aux conditions acoustiques qui évoluent sans cesse, à la fois pour le bruit particulier (bruit des éoliennes seules) qui dépend finement des conditions météorologiques, et pour le bruit résiduel qui dépend de toutes les autres sources de l’environnement et qui est fondamentalement de nature stochastique. La thèse vise à proposer un algorithme de contrôle du parc éolien en temps réel basé sur un nouveau paradigme de contrôle. On y étudie la possibilité de contrôler un parc éolien à partir d’un système en boite noire d’estimation temps-réel du niveau résiduel et du niveau particulier par séparation de sources. Dans le manuscrit, on définit tout d’abord une formulation du problème dans le cadre du contrôle en identifiant les problématiques propres à ce sujet, une définition des variables du problème et en se rattachant à l’état de l’art du contrôle. Ensuite, on propose deux solutions complètes de contrôle et une évaluation expérimentale. La première est une solution déterministe, qui s’appuie sur un algorithme d’optimisation combinatoire sous contrainte, et qui s’inspire du contrôle actuel des parcs éoliens tout en tenant compte de l’estimation par séparation de sources, alors supposée exacte. On y propose en outre une étude de la capacité du système déterministe à satisfaire le critère réglementaire français qui est aujourd’hui calculé à l’aide de médianes temporelles des variables acoustiques. La seconde est une solution stochastique, qui est basée sur une représentation d’état des variables acoustiques et des incertitudes gaussiennes. Elle inclut un filtrage de Kalman non-linéaire, afin de fusionner l’incertitude sur le modèle acoustique et l’incertitude de séparation de sources, un algorithme espérance-maximisation afin de ré-estimer les incertitudes du problème qui varient d’un parc à un autre, et une adaptation robuste de l’algorithme combinatoire afin de prendre en compte les incertitudes estimées / Currently, acoustic studies are required to set wind farms up. They must ensure the tranquility of the inhabitants around the farms in accordance with current regulations. For this purpose, acoustic measurements are made during a couple of weeks. When measuring, the wind turbines are periodically stopped in order to evaluate the difference between ambient noise levels (with the turbines on) and residual noise levels (with the turbines off). A curtailment plan is then computed and sent to the wind farm owner in order to set it up in the local turbine control system (SCADA). Currently, the curtailment plan roughly depends on the weather conditions and the time of the day which are allegedly correlated to the acoustic variables. In practice, it frequently leads to violations of the acoustic constraints or electrical power loss. This is because the acoustic conditions constantly and strongly evolve over time: the wind turbine noise level finely depends on the weather conditions and the residual noise level depends on all the other acoustic sources and has therefore a stochastic nature. The goal of the thesis is to design a principled real-time control algorithm for wind farms. To do so, we investigate the use of a black-box source separation system that estimates the residual noise level and the wind turbine noise level. We first provide a theoretical formulation of the problem by accounting for specific practical issues, by defining the variables of the problem and by binding these issues to the state of the art. Then, we propose two complete control solutions and run an experimental evaluation. The first solution is a deterministic algorithm based on a constrained combinatorial optimization algorithm, which is inspired by the current approach for controlling wind farms while exploiting the source separation system. Moreover, we present a study of its ability to fulfill the French acoustic constraints that are computed as temporal medians of the acoustic variables. The second solution is stochastic and based on a state-space model defined by means of Gaussian uncertainties. It features a nonlinear Kalman filter in order to fuse the uncertainties of the model and of the source separation system, an Expectation-Maximization algorithm that computes the uncertainties for a specific farm, and a robust variant of the deterministic algorithm that takes the estimated uncertainties into account when computing the optimal command

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