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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.
131

Mixed-Initiative Tile-Based Designer : Examining Expressive Range And Controllability For 2D Tile-Based Levels

Dolfe, Rafael January 2022 (has links)
This paper investigates the effectiveness of expressive range and controllability for 2-dimensional tile-based procedural content generation. Procedural content generation (PCG) is the automation of content, often in games, and tile-based PCG is when the generated content is constrained to a grid structure. Mixed-initiative PCG, which is the integration of user control into PCG, has been researched previously for tile-based PCG but the implementations have been limited by lack of breadth and user control over the algorithm. As a result, the expressive ranges and controllabilities of their algorithm have not been comprehensive, and in turn, the concepts of expressive range and controllability not thoroughly scrutinized. For the purpose of examining the concepts of expressive range and controllability, an implementation of declarative modelling, named Mixed-initiative Tile-based Designer (MTD), is made. The MTD combines the mission and shape grammar algorithm proposed by Dormans’ and the level generation system in Spelunky. Nine sets of input parameters, scenarios, are tested, each with 2000 levels generated. For each scenario, the expressive range of its output is examined using the standard evaluation metrics linearity and leniency. The results of the data sampling indicated that an analysis based on expressive range needs to be supported by additional analyses for the insights drawn to be more general. In particular, expressive range needs to be complemented by manual inspection, and linearity when applied to sufficiently complex levels needs to be complemented by additional evaluation metrics. On the other hand, controllability was found to have more significant limitations in its current form because of the normalization of the data that goes into the expressive range. One solution is instead to visualize the raw data of the expressive range and make liberal use of manual inspection. As a secondary study, the feasibility of implementing declarative modelling into 2-dimensional tile-based PCG is investigated through analyzing the MTD. In particular, the MTD’s user interface, procedural output and controllability is examined to determine whether declarative modelling is feasible for 2-dimensional tile-based PCG. / Denna artikel undersöker effektiviteten av uttrycksomfång och kontrollerbarhet för generering av 2-dimensionell rut-baserad procedurinnehåll. Procedurell innehållsgenerering (PCG) är automatisering av innehåll, ofta i spel, och rut-based PCG är när det genererade innehållet är begränsat till en rutnätsstruktur. Blandinitiativ PCG, som är integrationen av användarkontroll i PCG, har undersökts tidigare för rut-baserad PCG men implementeringarna har begränsats av brist på bredd och användarkontroll över algoritmen. Som ett resultat har uttrycksomfången och kontrollerbarheten av deras algoritm inte varit heltäckande, och i sin tur har begreppen uttrycksfullt omfång och kontrollerbarhet inte granskats noggrant. I syfte att undersöka begreppen uttrycksomfång och kontrollerbarhet görs en implementering av deklarativ modellering, benämnd Mixed-initiative Tile-based Designer (MTD). MTD:n kombinerar uppdrags-och formgrammatikalgoritmen som föreslagits av Dormans och nivågenereringssystemet i Spelunky. Nio uppsättningar ingångsparametrar, scenarier, testas, var och en med 2000 genererade nivåer. För varje scenario undersöks det uttrycksomfånget för dess utdata med hjälp av standardutvärderingsmåtten linjäritet och svårighet. Resultaten indikerade att en analys baserad på uttrycksomfång måste stödjas av ytterligare analyser för att insikterna ska bli mer generella. Speciellt måste uttrycksomfång kompletteras med manuell inspektion, och linjäritet när den tillämpas på tillräckligt komplexa nivåer måste kompletteras med ytterligare utvärderingsmått. Å andra sidan visade sig kontrollerbarhet ha mer betydande begränsningar i sin nuvarande form på grund av normaliseringen av data som går in i uttrycksomfånget. En lösning är istället att visualisera rådata från uttrycksomfånget och använda sig av manuell inspektion. Som en sekundär studie undersöks möjligheten att implementera deklarativ modellering i 2- dimensionell rut-baserad PCG genom att analysera MTD. I synnerhet undersöks MTD:s användargränssnitt, procedurutdata och kontrollerbarhet för att avgöra om deklarativ modellering är genomförbar för 2-dimensionell rut-baserad PCG.
132

Cadres pour l'analyse multi-perspective des infrastructures critiques / Frameworks for the multi-perspective analysis of critical infrastructures

Han, Fangyuan 23 January 2018 (has links)
Les infrastructures critiques (CIs) sont essentielles au fonctionnement de la société moderne. Leur sécurité et leur fiabilité sont les principales préoccupations. La complexité des CIs exige des approches d'analyse de système capables de voir le problème de plusieurs points de vue. La présente thèse porte sur l'intégration de la perspective de contrôle dans l'analyse de sécurité et de fiabilité des éléments de configuration. L'intégration est d'abord abordée par examiner les propriétés de contrôle d'un microgrid d'alimentation électrique. Un schéma basé sur la simulation est développé pour l'analyse sous différentes perspectives : le service d'approvisionnement, la contrôlabilité et la topologie. Un cadre basé sur la commande prédictive (MPC) est proposé pour analyser le microrgrid dans divers scenarios de défaillance. Ensuite, un cadre multi-perspectif est développé pour analyser les CIs considérant le service d'approvisionnement, la contrôlabilité et la topologie. Ce cadre permet d'identifier le rôle des éléments de CIs et de quantifier les conséquences de scénarios de défaillances, par rapport aux différents perspectives considérées. Afin de présenter le cadre d'analyse, un réseau de transport de gaz réel à travers plusieurs pays de l'Union européenne est considéré comme une étude de cas. En fin, un cadre d'optimisation a trois objectifs est proposé pour la conception de CI : la topologie du réseau et l'allocation des capacités de liaison sont optimisées minimisant la demande non fournie et la complexité structurelle du système, et en même temps maximisant la contrôlabilité du système. Une investigation approfondie sur les multiples objectifs considérés est effectuée pour tirer des informations utiles pour la conception du système. Les résultats de cette thèse démontrent l'importance de développer du cadre d'analyse des CIs considérant de plusieurs perspectives pertinentes pour la conception, l'opération et la protection des CIs. / Critical infrastructures (CIs) provide essential goods and service for modern society. Their safety and reliability are primary concerns. The complexity of CIs calls for approaches of system analysis capable of viewing the problem from multiple perspectives. The focus of the present thesis is on the integration of the control perspective into the safety and reliability analysis of CIs. The integration is first approached by investigating the control properties of a small network system, i.e., an electric power microgrid. A simulation-based scheme is developed for the analysis from different perspectives: supply service, controllability and topology. An optimization-based model predictive control framework is proposed to analyze the microgrid under various failure scenarios. Then, a multi-perspective framework is developed to analyze CIs with respect to supply service, controllability and topology. This framework enables identifying the role of the CI elements and quantifying the consequences of scenarios of multiple failures, with respect to the different perspectives considered. To demonstrate the analysis framework, a benchmark network representative of a real gas transmission network across several countries of the European Union (EU) is considered as case study. At last, a multi-objective optimization framework is proposed for complex CIs design: design of network topology and allocation of link capacities are performed in an optimal way to minimize the non-supplied demand and the structural complexity of the system, while at the same time to maximize the system controllability. Investigation on the multiple objectives considered is performed to retrieve useful insights for system design. The findings of this thesis demonstrate the importance of developing frameworks of analysis of CIs that allow considering different perspectives relevant for CIs design, operation and protection.
133

Controllability and stability of selectively wettable nanostructured membrane for oil/water separation

Sob, Peter Baonhe 12 1900 (has links)
M. Tech. (Department of Mechanical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / Presently, the current membrane technologies used in oil/water separation are inefficient with poor controllability and stability during oil/water separation. The has led to the current problem of membrane fouling and degradation during oil/water separation. Several approaches have been used to modify or design a better wettable surface with limited success since the current problem of membrane fouling is persisting. It is, therefore, necessary for scientists, engineers, and researchers to come up with a new membrane technology that will be more efficient with stable wettability and controllability during oil/water separation. Membranes are made up of nanoparticles on their surface, which are both random in nature. Furthermore, the collection of membrane particles to form mesh membranes are made of pores with further ransom spatial distribution. Thus, it was necessary to use the tools of stochastic processes to theoretically characterize these parameters. These parameters affect both internal and external factors as well as characteristics of random membrane particle and pores on wettability like surface tension and surface energy were established in the current project. Design and production of the membrane material according to established relationships was by both low and high-pressure spay jet coating in a controlled laboratory environment, and microscopic characterization performed using SEM. TEM, EDS, statistical analysis, and Image J particle analyzer. The spread, orientation, morphology, spatial distribution, inter-separation distances, surface roughness, surface smoothness, contact angles, surface density of the particle, mean size of the coated nanoparticle on the membrane surface after different coating rounds were analyzed so as to establish conditions for optimal wettability. The testing of produced membranes under the application of external and internal factors was done. A centrifugal pump was used to pump contaminated oil and water mixture through the membrane under a steady flow rate of 10 L/s with a gauge pressure of 180 kPa at room temperature conditions. The membrane materials from different coating rounds were tested for their abilities to produce pure collected water or oil particles in the collected water. The separated water was analyzed using oil and grease analysis US EPA method 1664B with the SPE-DEX 1000 oil and grease system. As revealed theoretically and validated experimentally, it was found that the random natures of nanoparticle size, the spatial distribution of membrane channels, and their morphology have impacts on surface energy-driven separability of oil and water mixture. It was also observed that the scattering of nanoparticles on the membrane surface during coating lowered surface energy, which enhanced oil/water separation. It was also revealed that there is an optimal nanoparticle size, scattering, morphology, and spatial distribution of membrane channels that offer better separation of water from oil. From the microscopy analysis, different microstructures were revealed for glass, ceramics, and sediment during LP and HP coating. The microstructure characterization showed different surface densities of nanoparticles, mean particle sizes, surface roughness or smoothness, and nanoparticles inter-separation distances. It was also revealed that the materials, which were more stable and efficient with more controlled wettability were glass, sediment, and ceramic HP 3rd rounds of coating. Clusters were observed on the membrane surface during HP and LP coating rounds with more clusters observed in LP coating when compared with HP coating. These clusters increased surface energy, which negatively affected oil/water separation. It was concluded that to improved the wettability surface. membrane clusters must be minimized during coating rounds. This thesis contributed new knowledge to existing body knowledge of membrane technology used in oil/water separation in a number of ways by: (1) Designing a new membrane surface with a more controlled, efficient, and stable wettability process during oil/water separation. (2) Applying the logic of surface energy-driven separability, which has not been previously used extensively to study membrane wettability. (3) Establishing a model for the optimal membrane pore sizes that offer optimal membrane wettability during oil/water separation. (4) Establishing a model for optimal nanoparticle coating that offers optimal membrane wettability during oil /water separation. (5) A great attempt was made in characterizing nanoparticle surface densities, spread, particle coating, and nanoparticles intensity on a wettable membrane surface.
134

Sufficient conditions for assignability of nonuniform dichotomy spectrum of discrete time-varying linear systems

Babiarz, Artur, Czornik, Adam, Siegmund, Stefan 22 February 2024 (has links)
We consider a version of the pole placement problem for tempered one sided linear discrete time time varying linear systems. We prove a sufficient condition for assignability of the nonuniform dichotomy spectrum by linear feedback. The main result is that the nonuniform dichotomy spectrum is assignable if the system is completely controllable and certain lower asymptotic bound for the controllability Gramian holds.
135

Performance Quantification of Interarea Oscillation Damping Using HVDC

Björk, Joakim January 2019 (has links)
With the transition towards renewable energy, and the deregulation of the electricity market, generation patterns and grid topology are changing. These changes increase the need for transfer capacity. One limiting factor, which sometimes leads to underutilization of the transmission grid, is interarea oscillations. These system-wide modes involve groups of generators oscillating relative to each other and are sometimes hard to control due to their scale and complexity. In this thesis we investigate how high-voltage direct current (HVDC) transmission can be used to attenuate interarea oscillations. The thesis has two main contributions. In the first contribution we show how the stability of two asynchronous grids can be improved by modulating the active power of a single interconnecting HVDC link. One concern with modulating HVDC active power is that the interaction between interarea modes of the two grids may have a negative impact on system stability. By studying the controllability Gramian, we show that it is always possible to improve the damping in both grids as long as the frequencies of their interarea modes are not too close. For simplified models, it is explicitly shown how the controllability, and therefore the achievable damping improvements, deteriorates as the frequency difference becomes small. The second contribution of the thesis is to show how coordinated control of two (or more) links can be used to avoid interaction between troublesome interarea modes. We investigate the performance of some multivariable control designs. In particular we look at input usage as well as robustness to measurement, communication, and actuator failures. Suitable controllers are thereby characterized. / Övergången till förnybar energi och avregleringen av elmarknaden leder till förändrade produktions-och överföringsmönster. Dessa förändringar medför behov av en ökad överföringskapacitet. En begränsande faktor, som kan leda till ett underutnyttjande av stamnätet, är interareapendlingar. Dessa systemövergripande pendlingar involverar grupper av generatorer som svänger i förhållande till varandra. Interareapendlingar är ibland svåra att styra på grund av deras skala och komplexitet. I denna avhandling undersöker vi hur förbindelser med högspänd likström, engleska high-voltage direct current (HVDC), kan användas för att dämpa interareapendlingar. Avhandlingen har två huvudbidrag. I det första bidraget visar vi hur stabiliteten hos två olika synkrona nät kan förbättras genom att modulera den aktiva effekten hos en enda HVDC-länk. Ett bekymmer med aktiv effektmodulering är att växelverkan mellan interareapendlingar hos de två näten kan ha en negativ inverkan på systemets stabilitet. Genom att studera styrbarhetsgramianen visar vi att det alltid är möjligt att förbättra dämpningen i båda näten så länge som frekvenserna hos deras interareapendlingar inte ligger för nära varandra. För förenklade modeller visas det uttryckligen hur styrbarheten och därmed de möjliga dämpningsförbättringarna, försämras då frekvensskillnaden blir liten. Avhandlings andra bidrag visar hur koordinerad styrning av två (eller fler) länkar kan användas för att undvika växelverkan mellan besvärliga interareapendlingar. Vi undersöker prestandan hos olika typer av flervariabla regulatorer. I synnerhet undersökers styrsignalsanvändning samt robusthet mot mät-, kommunikations- och aktuatorfel. Därigenom karakteriseras lämpliga regulatortyper. / <p>QC 20190308</p>
136

Interoception, Impulsivity and Coping with Stress : An investigation using the Novel Controllability Task

Bou Aram, Sinal January 2022 (has links)
Interoception, the signalling, processing, and perceptual representation of the visceral organs, together with trait impulsivity are in the present study examined using the Novel Controllability task (Mancinelli et al., 2021) as individual factors in coping behavior in response to stress. The coping process is conceptualized using the model of regulatory flexibility developed by Bonanno and Burton (2013). The results based on a sample of 39 healthy adults (M = 23,64 years, 22f/17m) do not support the hypothesis that the combined UPPS-P constructs are significantly related to interoception. For the coping process, the results suggest that: Negative Urgency is related to a negative initial appraisal of the stressor context leading to coping rigidity, by limiting the repertoire of strategies and the dynamic function of feedback; Positive Urgency is related to a larger dependency on emotions to guide decision making, motivating a “trial-and-error” coping approach; Sensation Seeking is related with an opposing style of emotion-focused coping where diminished threat perception and reduced sensitivity towards stimulus valence motivate a risk-taking approach, likely to pursue stimulation; Lack of Premeditation, the only facet of impulsivity convincingly related to interoception, is speculated to be associated with a dysregulation of interoceptive afferents facilitating a “here-and-now” attentional and coping focus. Despite lacking full support, the potential involvement of interoception as an internal stressor is discussed as a mediator in impulsive behavior, alongside general methodological issues with measuring interoception.
137

Théorie de contrôle et systèmes dynamiques / Control theory and dynamical systems

Lazrag, Ayadi 25 September 2014 (has links)
Cette thèse est divisée en trois parties. Dans la première partie, nous commençons par décrire des résultats très connus en théorie du contrôle géométrique tels que le théorème de Chow-Rashevsky, la condition de rang de Kalman, l'application Entrée-Sortie et le test linéaire. De plus, nous définissons et nous étudions brièvement la contrôlabilité locale au voisinage d'un contrôle de référence au premier et au second ordre. Dans la deuxième partie, nous donnons une preuve élémentaire du lemme de Franks linéaire pour les flots géodésiques qui utilise des techniques basiques de théorie du contrôle géométrique. Dans la dernière partie, étant donnée une variété Riemanienne compacte, nous prouvons un lemme de Franks uniforme au second ordre pour les flots géodésiques et on applique le résultat à la théorie de la persistance. Dans cette partie, nous introduisons avec plus de détails les notions de contrôlabilité locale au premier et au second ordre. En effet, nous donnons un résultat de contrôlabilité au second ordre dont la preuve est longue et technique. / This thesis is devided into three parts. In the first part we begin by describing some well known results in geometric control theory such as the Chow Rashevsky Theorem, the Kalman rank condition, the End-Point Mapping and the linear test. Moreover, we define and study briefly local controllability around a reference control at first and second order. In the second part we provide an elementary proof of the Franks lemma for geodesic flows using basic tools of geometric control theory. In the last part, given a compact Riemannian manifold, we prove a uniform Franks' lemma at second order for geodesic flows and apply the result in persistence theory. In this part we introduce with more details notions of local controllability at first and second order. In fact, we provide a second order controllability result whose proof is long and technical.
138

O conceito de estabilizabilidade fraca para sistemas lineares com saltos Markovianos / The weak stabilizability concept for linear systems with Markov jump

Manfrim, Amanda Liz Pacífico 08 March 2006 (has links)
Este trabalho introduz os conceitos de controlabilidade fraca e estabilizabilidade fraca para sistemas lineares com parâmetros sujeitos a saltos Markovianos a tempo discreto. É, inicialmente, construída uma coleção de matrizes C que se assemelha às matrizes de controlabilidade de sistemas lineares deterministicos. Essa coleção de matrizes C nos permite definir um conceito de controlabilidade fraca, requerendo que elas sejam de posto completo, assim como introduzir um conceito de estabilizabilidade fraca, dual ao conceito de detetabilidade fraca encontrado na literatura de sistemas com saltos de Markov. Uma característica importante do conceito de estabilizabilidade fraca é a de generalizar o conceito de estabilizabilidade na média quadrática, anteriormente encontrado na literatura. O papel do conceito da estabilizabilidade fraca no problema de filtragem é investigado através de casos de estudo. Estes casos de estudo são desenvolvidos no contexto do filtro de Kalman com observação do parâmetro de Markov e sugerem que a estabilizabilidade fraca em conjunto com a detetabilidade na média quadrática garantem que o estimador seja estável na média quadrática. / This work introduces weak controllability and weak stabilizability concepts for discretetime Markov jump linear system. We introduce a collection of matrices C that resembles controllability matrices of deterministic linear systems. The collection of matrices C allows us to define a weak controllability concept by requiring that the matrices are full rank, as well as to introduce a weak stabilizability concept that is a dual of the weak detectability concept found in the literature of Markov jump systems. An important feature of the introduced concept is that it generalizes the previous concept of mean square stabilizability. The role that the weak stabilizability concept plays in the filtering problem is investigated via case studies. These case studies are developed in the context of Kalman filtering with observation of the Markov parameter, they suggest that weak stabilizability together with mean square stabilizability ensure that the state estimator is mean square stable.
139

Controlabilidade e observabilidade em equações diferenciais ordinárias generalizadas e aplicações / Controllability and observability in generalized ordinary differential equations and applications

Silva, Fernanda Andrade da 30 October 2017 (has links)
Neste trabalho, introduzimos os conceitos de controlabilidade e de observabilidade para equações diferenciais ordinárias generalizadas, apresentamos resultados inéditos sobre condições suficientes e necessárias para controlabilidade e para observabilidade para estas equações e também apresentaremos uma aplicação. Utilizando teoremas de correspondência entre equações diferenciais ordinárias generalizadas e outras equações diferenciais, traduzimos os resultados obtidos para os casos particulares de controlabilidade e observabilidade para equações diferenciais em medida e equações diferencias com impulsos. O fato de trabalharmos no ambiente das equações diferenciais ordinárias generalizadas permitiu que os resultados obtidos pudessem envolver funções com muitas descontinuidades e muito oscilantes, ou seja, de variação ilimitada. Os resultados novos apresentados aqui estão contidos no artigo [21] que se encontra em fase final de redação e será submetido à publicação em breve. / In this work, we introduce concepts of controllability and observability for generalized ordinary differential equations, we present new results on necessary and sufficient conditions for controllability and observability for these equations and we also present an application. Using theorems of correspondence between generalized ordinary differential equations and other differential equations, we translate the results obtained for the particular cases of controllability and observability for measure differential equations and differential equations with impulses. The fact that we work in the framework of generalized ordinary differential equations allows us to obtain results where the functions involved can have many discontinuities and be highly oscillating, that is, of unbounded variation. The new results presented here are contained in the preprint [21] which is under final revision and will soon be submitted for publication.
140

Eléments d'analyse et de contrôle dans le problème de Hele-Shaw / Elements of analysis and control in the Hele-Shaw problem

Runge, Vincent 25 September 2014 (has links)
Cette thèse porte sur le traitement mathématique du problème de Hele-Shaw dans l’approximation de Stokes-Leibenson. À l’aide d’une transformation de type Helmholtz- Kirchhoff, nous explicitons une équation d’évolution du contour fluide valable pour tout type d’écoulement plan. Cette équation généralise des résultats précédents et permet alors d’établir un schéma numérique performant dit du quasi-contour, qui se réduit à un problème de Cauchy. Nous considérons ensuite l’étude du problème par transformations conformes menant à l’équation de Polubarinova-Galin. Dans le cas simple d’un contour représenté par un trinôme à coefficients réels, nous réussissons à expliciter la solution exacte du problème. Notons que les trajectoires des solutions exactes permettent de préciser la position de la frontière des domaines d’univalence décrits par les trinômes. Enfin, nous introduisons des paramètres de contrôle sous forme de coefficients d’un multipôle superposé à la source. Des conditions suffisantes de contrôlabilité sont établies et des résultats de contrôle optimal sont explicités pour les solutions binomiales et trinomiales. L’introduction de paramètres de contrôle permet de comprendre le lien qui relie les moments de Richardson à l’équation de Polubarinova-Galin. / This PhD thesis deals with the mathematical treatment of the Hele–Shaw problem in the Stokes–Leibenson approximation. By an Helmholtz–Kirchhoff transformation, we exhibited an evolutive equation of the fluid contour applicable to all type of planar fows. This equation generalizes previous results and also allows to state an efficient numerical scheme called quasi-contour’s, which is a simple Cauchy problem. We then consider the study of this problem using conformal transformations leading to the Polubarinova-Galin equation. In the simple case of a contour representing by a trinomial with real coefficients, we succeeded in exhibiting the exact solution of the problem. Notice that the trajectories of the exact solutions enable to precise the position of frontiers of univalent domains described by trinomials. Finally, we introduce control parameters under the form of coefficients of a multipole superposed to the source. Sufficient conditions of controllability are stated and results on optimal control established for the binomial and trinomial cases. Introduction of control parameters allows us to understand the link, which bound Richardson’s moments to the Polubarinova-Galin equation.

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