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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.
391

Ekonomistyrning, på liv eller död? : En kvalitativ studie om controllers användning av styrmedel inom sjukvården. / Management accounting, of life or death?

Andersson, Christian, Bonnevier, Niklas, Nilsson, Alexander January 2015 (has links)
Bakgrund: Sjukvården beskrivs som oerhört komplex och genom bland annat utveckling av ny och dyr teknik, som i sin tur genererar bättre vård, gör det svårt för sjukhus att hålla sin budget. En controller har en fundamental roll i en organisations ekonomistyrning och ska med hjälp av diverse styrmedel styra och kontrollera så att verksamheten drivs mot ekonomiska mål. Syfte: Syftet med uppsatsen var att beskriva och analysera hur en controller inom sjukvården använder ekonomiska styrmedel för att nå ekonomisk måluppfyllelse samt skapa en förståelse för hur en controller hanterar balansgången mellan ekonomisk måluppfyllelse och vårdkvalité. Metod: Uppsatsen är formad med en kvalitativ forskningsdesign. En flerfallstudie har använts som forskningsstrategi där den empiriska datan är insamlad genom ostrukturerade intervjuer med anställda vid två sjukhus i Småland, länssjukhuset i Kalmar och centrallasarettet i Växjö. Det teoretiska avsnittet är byggt med data som insamlats från litteratur och vetenskapliga artiklar som varit tillgängliga via Linnéuniversitetets bibliotekskatalog. Slutsats: De resultat som framkommer av studien påvisar att en controllerns användning av styrmedel tenderar att fokusera på ekonomisk måluppfyllelse. Genom användning i större utsträckning av de styrmedel som är under utveckling finns möjligheter för controllern att även påverka vårdkvalité. / Background: Health care organisations are seen as complex due to the all time ongoing development of new and expensive technology. Which in other hand generates better quality but makes it hard for these organisations to keep within their budget. A controller has an fundamental role in the work with managing accounting within organisations. With the help of a setup of control instruments the controller are to manage and control so that operations helps the organisation to reach its economic targets. Purpose: Our purpose with this thesis were to study a selection of health care organisation. Through explaining and analyzing the controllers usage of control instruments to reach economic targets and develop an understandning for how a controller are handling priority between economic targets and care quality. Method: The thesis were formed with a qualtivive research design. With a strategy of studying multiple cases were the empirical data gathered from interviews with employees at two hospitals in Småland. Our theoretical chapter is built on information collected from litterature and scientific articles that were available through the library catalogue at Linnaeus University. Conclusion: The results of this thesis shows that a controllers usage of control instruments focus on economic targets rather then care quality. With an greater use of the control instruments that are under development the controller has an opportunity to influence on care quality.
392

Compositional Synthesis and Most General Controllers

Klein, Joachim 18 December 2013 (has links) (PDF)
Given a formal model of the behavior of a system, an objective and some notion of control the goal of controller synthesis is to construct a (finite-state) controller that ensures that the system always satisfies the objective. Often, the controller can base its decisions only on limited observations of the system. This notion of limited observability induces a partial-information game between the controller and the uncontrollable part of the system. A successful controller then realizes an observation-based strategy that enforces the objective. In this thesis we consider the controller synthesis problem in the linear-time setting where the behavior of the system is given as a nondeterministic, labeled transitions system A, where the controller can only partially observe and control the behavior of A. The goal of the thesis is to develop a compositional approach for constructing controllers, suitable to treat conjunctive cascades of linear-time objectives P_1, P_2, ..., P_k in an online manner. We iteratively construct a controller C_1 for system A enforcing P_1, then a controller C_2 enforcing P_2 for the parallel composition of the first controller with the system, and so on. It is crucial for this approach that each controller C_i enforces P_i in a most general manner, being as permissive as possible. Otherwise, behavior that is needed to enforce subsequent objectives could be prematurely removed. Standard notions of strategies and controllers only allow the most general treatment for the limited class of safety objectives. We introduce a novel concept of most general strategies and controllers suited for the compositional treatment of objectives beyond safety. We demonstrate the existence of most general controllers for all enforceable, observation-based omega-regular objectives and provide algorithms for the construction of such most general controllers, with specialized variants for the subclass of safety and co-safety objectives. We furthermore adapt and apply our general framework for the compositional synthesis of most general controllers to the setting of exogenous coordination in the context of the channel-based coordination language Reo and the constraint automata framework and report on our implementation in the verification toolset Vereofy. The construction of most general controllers in Vereofy for omega-regular objectives relies on our tool ltl2dstar for generating deterministic omega-automata from Linear Temporal Logic (LTL) formulas. We introduce a generic improvement for exploiting insensitiveness to stuttering during the determinization construction and evaluate its effectiveness in practice. We further investigate the performance of recently proposed variants of Safra\'s determinization construction in practice.
393

Optimal Design Of Truss Structures With Actuators

Akgoz, Asli 01 December 2003 (has links) (PDF)
Smart structures become highly popular with the developing technology. The aim of this study is to develop a basic model, which can be also used in the design of more complex systems by performing simultaneous optimization of a structure and associated controller with respect to some design parameters and feedback gains. In this thesis work, two smart structures are used as case studies and their results are compared with the available results in the literature. The first case study is simple twobar truss problem controlled by either one or two actuators. This problem is solved both numerically and analytically. The latter is a twenty-element parabolic truss, which is controlled by four actuators. This problem is solved numerically only. In the optimization process, the design parameters are taken as the cross sectional areas of bar elements, positions and/or number of actuators, and the elements of closed loop gain matrix. In the second case study, in addition to these parameters, shape design parameters are also optimized. A coordinate transformation is applied in both cases from the displacement space to the modal space. The modal model reduction method is used in the design of second problem. The optimization goal in both cases studies is to minimize the system energy while satisfying some frequency and mass constraints. In the second case study, in addition to the original objective function, system controllability and stability robustness are also maximized. In the solution of design problem, two optimization algorithms are used one embedded within the other. In the outer loop, a hide and seek simulated annealing algorithm optimizes structural design parameters, and positions and/or number of actuators. In order to generate a candidate design family for this level, optimal closed loop gain matrices are calculated by using MATLAB&reg / .
394

A novel parametrized controller reduction technique based on different closed-loop configurations

Houlis, Pantazis Constantine January 2009 (has links)
This Thesis is concerned with the approximation of high order controllers or the controller reduction problem. We firstly consider approximating high-order controllers by low order controllers based on the closed-loop system approximation. By approximating the closed-loop system transfer function, we derive a new parametrized double-sided frequency weighted model reduction problem. The formulas for the input and output weights are derived using three closed-loop system configurations: (i) by placing a controller in cascade with the plant, (ii) by placing a controller in the feedback path, and (iii) by using the linear fractional transformation (LFT) representation. One of the weights will be a function of a free parameter which can be varied in the resultant frequency weighted model reduction problem. We show that by using standard frequency weighted model reduction techniques, the approximation error can be easily reduced by varying the free parameter to give more accurate low order controllers. A method for choosing the free parameter to get optimal results is being suggested. A number of practical examples are used to show the effectiveness of the proposed controller reduction method. We have then considered the relationships between the closed-loop system con gurations which can be expressed using a classical control block diagram or a modern control block diagram (LFT). Formulas are derived to convert a closed-loop system represented by a classical control block diagram to a closed-loop system represented by a modern control block diagram and vice versa.
395

Bezdotykové ovládání interaktivních výukových aplikací s využitím technologie Leap Motion / Contactless control of interactive training applications using Leap Motion technology

SVATEK, Tomáš January 2015 (has links)
In its theoretical part, this thesis treats possibilities of using no-touch technology Leap Motion in elementary school lessons for operating interactive applications focused on physics education. The thesis investigates the ways in which it is possible to operate already published applications which are not programmed specifically for a no-touch technology and which are, however, intended for work with an interactive whiteboard or for a standard computer work. Their advantages and disadvantages are discussed as well. The thesis deals, among other things, with the availability of relevant applications and offers a summary of information about Leap Motion technology and of opportunities for replacing interactive whiteboards. The thesis also includes a description of the technology and of the potential for developing your own applications. The aim of the practical part is to create a new didactic application which will be tested in lessons. This part also includes a poll which will find out what is the interest in Leap Motion technology among teachers.
396

Projeto de controladores para o seguimento de referências periódicas em sistemas com atuadores saturantes

Flores, Jeferson Vieira January 2012 (has links)
Este trabalho aborda o problema de seguimento e rejeição de sinais periódicos em sistemas lineares sujeitos a saturação nos atuadores. Para garantir o seguimento/rejeição, dois controladores baseados no princípio do modelo interno são considerados: o primeiro baseia-se no modelo interno em sua formulação clássica, isto é, um controlador dinâmico contendo um número finito de modos (marginalmente) instáveis da referência/perturbação é introduzido na malha de controle, em uma abordagem chamada de controladores ressonantes; a segunda abordagem considera o controlador repetitivo, onde um elemento de atraso é inserido namalha de controle emumlaço de realimentação positiva, fazendo o papel do modelo interno de ordem infinita. Nos dois casos, o objetivo principal é a obtenção de condições na forma de inequações matriciais lineares (do inglês, Linear Matrix Inequalities - LMIs) para a síntese simultânea de uma realimentação de estados estabilizante e do ganho do laço estático de anti-windup. Partindo do pressuposto que as referências e perturbações pertencem a um certo conjunto admissível, estes ganhos garantem que as trajetórias do sistema em malha fechada inciadas em um certo conjunto elipsoidal convergem para outro conjunto elipsoidal invariante contido na região de operação linear do sistema. Nesta região, a presença do modelo interno na malha de controle garante o seguimento e a rejeição dos sinais de interesse. Nas duas abordagens são propostos problemas de otimização visando a maximização do conjunto invariante de estados admissíveis e/ou a maximização do conjunto de referências/perturbações admissíveis. Extensões da metodologia para sistemas de tempo discreto também são apresentadas. / This work addresses the tracking/rejection problem of periodic signals for linear systems subject to control saturation. To ensure the tracking/rejection, two internal model based controllers are considered: the first one considers the internal model in a classical framework, i.e. a dynamic controller containing a finite number of (marginally) unstable modes of the reference/disturbance signal is introduced in the control loop. In this work, this approach is called resonant controller. The second approach considers the repetitive controller, where a delay element is introduced in the control loop in a positive feedback loop, playing the role of an infinite order internal model. In both cases, the main objective is to obtain conditions in the form of LMIs to simultaneously compute a stabilizing state feedback gain and an anti-windup gain. Assuming that the references and disturbances signals belong to a certain admissible set, these gains guarantee that the trajectories of the closed-loop system starting in a certain ellipsoidal set contract to another invariant ellipsoidal set inside the linearity region of the closed-loop system. In this region the presence of the internal model ensures tracking/rejection of the considered periodic signals. In both frameworks, optimization problems aiming at the maximization of the invariant set of admissible states and/or the maximization of the set of admissible references/disturbances are proposed. Extensions of the proposed framework to discrete-time systems are also presented.
397

Projeto de controladores para o seguimento de referências periódicas em sistemas com atuadores saturantes

Flores, Jeferson Vieira January 2012 (has links)
Este trabalho aborda o problema de seguimento e rejeição de sinais periódicos em sistemas lineares sujeitos a saturação nos atuadores. Para garantir o seguimento/rejeição, dois controladores baseados no princípio do modelo interno são considerados: o primeiro baseia-se no modelo interno em sua formulação clássica, isto é, um controlador dinâmico contendo um número finito de modos (marginalmente) instáveis da referência/perturbação é introduzido na malha de controle, em uma abordagem chamada de controladores ressonantes; a segunda abordagem considera o controlador repetitivo, onde um elemento de atraso é inserido namalha de controle emumlaço de realimentação positiva, fazendo o papel do modelo interno de ordem infinita. Nos dois casos, o objetivo principal é a obtenção de condições na forma de inequações matriciais lineares (do inglês, Linear Matrix Inequalities - LMIs) para a síntese simultânea de uma realimentação de estados estabilizante e do ganho do laço estático de anti-windup. Partindo do pressuposto que as referências e perturbações pertencem a um certo conjunto admissível, estes ganhos garantem que as trajetórias do sistema em malha fechada inciadas em um certo conjunto elipsoidal convergem para outro conjunto elipsoidal invariante contido na região de operação linear do sistema. Nesta região, a presença do modelo interno na malha de controle garante o seguimento e a rejeição dos sinais de interesse. Nas duas abordagens são propostos problemas de otimização visando a maximização do conjunto invariante de estados admissíveis e/ou a maximização do conjunto de referências/perturbações admissíveis. Extensões da metodologia para sistemas de tempo discreto também são apresentadas. / This work addresses the tracking/rejection problem of periodic signals for linear systems subject to control saturation. To ensure the tracking/rejection, two internal model based controllers are considered: the first one considers the internal model in a classical framework, i.e. a dynamic controller containing a finite number of (marginally) unstable modes of the reference/disturbance signal is introduced in the control loop. In this work, this approach is called resonant controller. The second approach considers the repetitive controller, where a delay element is introduced in the control loop in a positive feedback loop, playing the role of an infinite order internal model. In both cases, the main objective is to obtain conditions in the form of LMIs to simultaneously compute a stabilizing state feedback gain and an anti-windup gain. Assuming that the references and disturbances signals belong to a certain admissible set, these gains guarantee that the trajectories of the closed-loop system starting in a certain ellipsoidal set contract to another invariant ellipsoidal set inside the linearity region of the closed-loop system. In this region the presence of the internal model ensures tracking/rejection of the considered periodic signals. In both frameworks, optimization problems aiming at the maximization of the invariant set of admissible states and/or the maximization of the set of admissible references/disturbances are proposed. Extensions of the proposed framework to discrete-time systems are also presented.
398

Controle preditivo robusto com realimentação de saída. / Robust MPC with output feedback.

José Manuel Gonzalez Tubio Perez 17 March 2006 (has links)
Esse trabalho apresenta uma contribuição para o projeto de um controlador MPC robusto quanto à estabilidade baseado na realimentação da saída e admitindo restrições nas entradas e incertezas no modelo da planta. Ele estende a abordagem existente para o projeto de um MPC considerando o caso particular de um modelo em espaço de estados, onde o estado é lido diretamente da planta, sendo aplicado para a situação em que o sistema escolhido de entradas possa ficar saturado ou que o processo seja representado por um modelo diferente do modelo considerado na função objetivo do controlador. Para isso, o MPC se propõe a resolver o problema de otimização em dois estágios: No estágio off-line, vários controladores sem restrição são obtidos a partir de um problema de otimização onde inequações de Lyapunov são acrescentadas ao problema como restrições de forma a garantir a contração do estado (estabilidade). Esses controladores, representados por uma matriz de ganhos, correspondem a todas configurações possíveis de saturação das variáveis manipuladas para um dado conjunto possível de variáveis controladas. Nessas combinações, incluídas como restrições no controlador, todos os modelos previstos para o processo são considerados. Dessa forma, perdendo-se uma entrada, o subconjunto de saídas controladas pode ser alterado.Na versão anterior do método proposto por Rodrigues & Odloak (2005), esse estágio off-line envolve um observador de estados o que dificulta a solução do problema de otimização do MPC robusto, consumindo grande tempo computacional. Além disso, requer uma solução inicial viável que nem sempre é trivial. Com a versão proposta do sistema de modelo espaço estado, o estimador de estado torna-se desnecessário pois o estado passa a ser medido. Na etapa on-line do projeto do controlador, uma lei ótima de controle é obtida a partir da combinação convexa das configurações de controle que correspondem ao conjunto de variáveis manipuladas disponíveis (não saturadas). Também nessa etapa é considerada a incerteza do modelo utilizado pelo controlador. O controlador proposto é testado com alguns exemplos simulados a partir de modelos obtidos na indústria de processo. / In this work, it is presented a contribution to the design of a robust MPC with output feedback, input constraints and uncertain model. This work extends existing approaches by considering a particular non-minimal state space model, which transforms the output feedback strategy into a state feedback strategy. The controller is developed to the case in which the system inputs may become saturated and the model is uncertain. We follow a two stages approach: In the off-line stage, a series of unconstrained robust MPCs is obtained by including in the control optimization problem, inequality constraints that force the state of the closed-loop system to contract along the time. Each of these controllers, represented by a gain matrix, is associated to particular sets of manipulated inputs and controlled outputs. When one manipulated input becomes saturated, we may need to reduce the set of controlled variables. In the existing version of the method, the closed loop system involves a state observer that makes the solution to the robust MPC optimization problem a time consuming step. The problem also requires an initial solution that may not be trivial to find. With the adopted version of the system state space model, the state filter becomes trivial and the state can be considered measured. In the on-line step of the proposed controller design, a sub optimal control law is obtained by combining control configurations that correspond to particular subsets of available manipulated inputs. The method is illustrated with simulation examples of the process industry.
399

Projeto de controladores para o seguimento de referências periódicas em sistemas com atuadores saturantes

Flores, Jeferson Vieira January 2012 (has links)
Este trabalho aborda o problema de seguimento e rejeição de sinais periódicos em sistemas lineares sujeitos a saturação nos atuadores. Para garantir o seguimento/rejeição, dois controladores baseados no princípio do modelo interno são considerados: o primeiro baseia-se no modelo interno em sua formulação clássica, isto é, um controlador dinâmico contendo um número finito de modos (marginalmente) instáveis da referência/perturbação é introduzido na malha de controle, em uma abordagem chamada de controladores ressonantes; a segunda abordagem considera o controlador repetitivo, onde um elemento de atraso é inserido namalha de controle emumlaço de realimentação positiva, fazendo o papel do modelo interno de ordem infinita. Nos dois casos, o objetivo principal é a obtenção de condições na forma de inequações matriciais lineares (do inglês, Linear Matrix Inequalities - LMIs) para a síntese simultânea de uma realimentação de estados estabilizante e do ganho do laço estático de anti-windup. Partindo do pressuposto que as referências e perturbações pertencem a um certo conjunto admissível, estes ganhos garantem que as trajetórias do sistema em malha fechada inciadas em um certo conjunto elipsoidal convergem para outro conjunto elipsoidal invariante contido na região de operação linear do sistema. Nesta região, a presença do modelo interno na malha de controle garante o seguimento e a rejeição dos sinais de interesse. Nas duas abordagens são propostos problemas de otimização visando a maximização do conjunto invariante de estados admissíveis e/ou a maximização do conjunto de referências/perturbações admissíveis. Extensões da metodologia para sistemas de tempo discreto também são apresentadas. / This work addresses the tracking/rejection problem of periodic signals for linear systems subject to control saturation. To ensure the tracking/rejection, two internal model based controllers are considered: the first one considers the internal model in a classical framework, i.e. a dynamic controller containing a finite number of (marginally) unstable modes of the reference/disturbance signal is introduced in the control loop. In this work, this approach is called resonant controller. The second approach considers the repetitive controller, where a delay element is introduced in the control loop in a positive feedback loop, playing the role of an infinite order internal model. In both cases, the main objective is to obtain conditions in the form of LMIs to simultaneously compute a stabilizing state feedback gain and an anti-windup gain. Assuming that the references and disturbances signals belong to a certain admissible set, these gains guarantee that the trajectories of the closed-loop system starting in a certain ellipsoidal set contract to another invariant ellipsoidal set inside the linearity region of the closed-loop system. In this region the presence of the internal model ensures tracking/rejection of the considered periodic signals. In both frameworks, optimization problems aiming at the maximization of the invariant set of admissible states and/or the maximization of the set of admissible references/disturbances are proposed. Extensions of the proposed framework to discrete-time systems are also presented.
400

CONTROLE DE CORRENTE APLICADO EM INVERSOR MONOFÁSICO DE TENSÃO / CURRENT CONTROL APPLIED IN SINGLE-PHASE VOLTAGE INVERTERS

Lima, Marcel Soares 20 February 2015 (has links)
Made available in DSpace on 2016-08-17T14:52:39Z (GMT). No. of bitstreams: 1 DISSERTACAO_MARCEL SOARES LIMA.pdf: 17818100 bytes, checksum: 95b36384b873fd5da81040a537b53ec1 (MD5) Previous issue date: 2015-02-20 / With advancement of power electronics and the wide range of applications involving single-phase inverter voltage, current controllers has gained great prominence, because they control the flow of energy supplied to the grid or to a load and compensate some quality energy problems. For this, various techniques for controlling power has been studied in order to meet the robustness characteristics, accuracy and speed of response. In addition, another important characteristic, which has been adopted for accurately determining the choice of the current driver is the possibility of eliminating disturbances in specific frequency, such as those caused by harmonicas of the fundamental signal. This paper presents the study, analysis and resonant controller design. Since this controller is equivalent to adding two PI controllers synchronously, a positive sequence and negative sequence other, implemented in the stationary frame of reference, we will investigate the possible resonance structures of controlling synchronous equivalent to PI controllers, and vector classic and the advantages and disadvantages of each. The analyses of resonant controllers are held in the continuous domain and then the drivers are implemented in discrete domain, taking into account the computational delay. It is also performed the analysis and design of strategies for controlling resonant with and without a delay compensator. Finally, experimental tests will be performed to confirm the analyzes in this paper. / Com o avanço da eletrônica de potência e a vasta gama de aplicações que envolvem os inversores monofásicos de tensão, os controladores de corrente têm ganhado grande destaque, pois controlam o fluxo de energia fornecida à rede elétrica ou a uma carga e compensam alguns problemas de qualidade de energia. Para isso, diversas técnicas de controladores de corrente têm sido estudadas com o intuito de atender as características de robustez, precisão e rapidez na resposta. Além disso, outra característica importante, e que tem sido rigorosamente adotada para determinar a escolha dos controladores de corrente, é a possibilidade de eliminar distúrbios em frequências específicas, como por exemplo, aqueles causados por harmônicas do sinal fundamental. Esta dissertação apresenta o estudo, análise e projeto do controlador ressonante. Uma vez que este controlador é equivalente à adição de dois controladores PI síncronos, um de sequência positiva e outro de sequência negativa, implementados no referencial estacionário, serão investigados as possíveis estruturas dos controladores ressonantes equivalentes aos controladores PI síncronos, clássico e vetorial, bem como as vantagens e desvantagens de cada um. As análises dos controladores ressonantes são realizadas no dominio contínuo e, posteriormente, os controladores são implementados no dominio discreto, levando em consideração o atraso computacional. Também é realizada a análise e projeto das estratégias de controladores ressonantes com e sem um compensador de atraso. Por fim, serão realizados ensaios experimentais para confirmar as análises realizadas no decorrer deste trabalho.

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