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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.
181

Studium av Othellospelande program : Design, algoritmer och implementation / A study of strong Othello programs : Design, algorithms and implementation

Ekbom, Andreas January 2003 (has links)
<p>Att "smarta" brädspelande datorprogram har blivit mycket bättre under de senaste årtiondena har väl knappast kunnat undgå någon. Med brädspel menar jag spel såsom Go, Othello, Backgammon och Schack. Idag spelar program, som körs på en reguljär PC, bättre än de flesta människor. Vad är det som gör dessa program så bra? Hur kan man lära en dator att spela ett så pass komplext spel som Othello på en sådan nivå att ingen människa har en chans att vinna? I detta examensarbete kommer jag att försöka förklara mekanismerna bakom ett toppspelande Othelloprogram. Jag har dessutom implementerat ett eget Othellospelande program som jag använt som testapplikation för att prova olika sökmetoder, metoder för att öka exekveringshastigheten och tekniker för att öka spelskickligheten. Jag kommer att presentera empiriska data där jag utvärderar och jämför flera andra program med mitt eget.</p>
182

Polyhydroxyl and Polyphosphorylcholine functionalized Silica for Hydrophilic interaction liquid Chromatography- Synthesis, characterization and application

Bui, Nhat Thi Hong January 2012 (has links)
This thesis focuses on the development of new stationary phases for use in hydrophilic interaction liquid chromatography using TRIS-based and phosphorylcholine typed monomers and porous silica particles as starting substrates. In this thesis, several ways of polymerizing highly hydrophilic mono­mers onto pore surfaces of silica supports are described, based on several “grafting from” schemes. “Controlled/living” radical polymerizations including atom transfer radical polymerization (ATRP) and iniferter-mediated polymerization in conjunction with conventional free radical polymerization are demonstrated to be successful tools for grafting different hydrophilic monomers (polyhydroxyl and phosphorylcholine [meth]acrylamide/acrylates) onto the silica surfaces. Reaction solvents are proven to play an essential role to achieve efficient graft polymerization of activated silica surfaces with these amphiphilic vinylic monomers, which is difficult because of their restricted access to the activated surface in solvents that can be used because of solubility constraints. Two tentacle TRIS-based polymer grafted silica, namely TRIS-WAX – TRIS functionality bonded to silica via a C–N–C imine bond and TRIS-Amide – TRIS bonded to silica via an amide bond, prove to be useful as stationary phases for hydrophilic interaction chromatography (HILIC).The TRIS-WAX exhibits a mixed mode hydrophilic partitioning and weak anion exchange (HILIC/WAX) retention mechanism while retention by hydrophilic partitioning is the dominant mechanism on the neutral TRIS-Amide phase which lacks weak anion exchange (WAX) properties. Interestingly, both these phases have selectivities that are radically different from most commercial HILIC stationary phases. Finally, a method is demonstrated for synthesizing a stratified (graft-copolymerized) silica material based on N,N′-methylenebisacrylamide and 2-methacryloyloxyethyl phosphorylcholine (MPC) using a “controlled/living” photoiniferter-mediated polymerization from the N,N-diethyldithiocarbamate iniferter moiety immobilized silica surfaces. This polymerization method proves to be successful for graft-blockcopolymerization of different highly hydrophilic monomers onto the activated surfaces of porous silica. In this way, silica surfaces are grafted with a cross-linked amide-based hydrogel, on top of which a tentacle zwitterionic phosphorylcholine-typed layer is synthesized. The resulted material proves to be useful for HILIC separations and possesses different selectivity for the tested organic acids compared to that of commercial ZIC-cHILIC stationary phase.
183

Linear-time invariant Positive Systems: Stabilization and the Servomechanism Problem

Roszak, Bartek 17 January 2012 (has links)
Positive systems, which carry the well known property of confining the state, output, and/or input variables to the nonnegative orphant, are of great practical importance, as the nonnegative property occurs quite frequently in numerous applications and in nature. These type of systems frequently occur in hydrology where they are used to model natural and artificial networks of reservoirs; in biology where they are used to describe the transportation, accumulation, and drainage processes of elements and compounds like hormones, glucose, insulin, and metals; and in stocking, industrial, and engineering systems where chemical reactions, heat exchanges, and distillation processes take place. The interest of this dissertation is in two key problems: positive stabilization and the positive servomechanism problem. In particular, this thesis outlines the necessary and sufficient conditions for the stabilization of positive linear time-invariant (LTI) systems using state feedback control, along with providing an algorithm for constructing such a stabilizing regulator. Moreover, the results on stabilization also encompass the two problems of the positive separation principle and stabilization via observer design. The second, and most emphasized, problem of this dissertation considers the positive servomechanism problem for both single-input single-output (SISO) and multi-input multi-output (MIMO) stable positive LTI systems. The study of the positive servomechanism problem focuses on the tracking problem of nonnegative constant reference signals for unknown/known stable SISO/MIMO positive LTI systems with nonnegative unmeasurable/measurable constant disturbances via switching tuning clamping regulators (TcR), linear quadratic clamping regulators (LTQcR), and ending with MPC control. Finally, all theoretical results on the positive servomechanism problem are justified via numerous experimental results on a waterworks system.
184

Linear-time invariant Positive Systems: Stabilization and the Servomechanism Problem

Roszak, Bartek 17 January 2012 (has links)
Positive systems, which carry the well known property of confining the state, output, and/or input variables to the nonnegative orphant, are of great practical importance, as the nonnegative property occurs quite frequently in numerous applications and in nature. These type of systems frequently occur in hydrology where they are used to model natural and artificial networks of reservoirs; in biology where they are used to describe the transportation, accumulation, and drainage processes of elements and compounds like hormones, glucose, insulin, and metals; and in stocking, industrial, and engineering systems where chemical reactions, heat exchanges, and distillation processes take place. The interest of this dissertation is in two key problems: positive stabilization and the positive servomechanism problem. In particular, this thesis outlines the necessary and sufficient conditions for the stabilization of positive linear time-invariant (LTI) systems using state feedback control, along with providing an algorithm for constructing such a stabilizing regulator. Moreover, the results on stabilization also encompass the two problems of the positive separation principle and stabilization via observer design. The second, and most emphasized, problem of this dissertation considers the positive servomechanism problem for both single-input single-output (SISO) and multi-input multi-output (MIMO) stable positive LTI systems. The study of the positive servomechanism problem focuses on the tracking problem of nonnegative constant reference signals for unknown/known stable SISO/MIMO positive LTI systems with nonnegative unmeasurable/measurable constant disturbances via switching tuning clamping regulators (TcR), linear quadratic clamping regulators (LTQcR), and ending with MPC control. Finally, all theoretical results on the positive servomechanism problem are justified via numerous experimental results on a waterworks system.
185

Model Predictive Control for Series-Parallel Plug-In Hybrid Electrical Vehicle

Engman, Jimmy January 2011 (has links)
The automotive industry is required to deal with increasingly stringent legislationfor greenhouse gases. Hybrid Electric Vehicles, HEV, are gaining acceptance as thefuture path of lower emissions and fuel consumption. The increased complexityof multiple prime movers demand more advanced control systems, where futuredriving conditions also becomes interesting. For a plug-in Hybrid Electric Vehicle,PIHEV, it is important to utilize the comparatively inexpensive electric energybefore the driving cycle is complete, this for minimize the cost of the driving cycle,since the battery in a PIHEV can be charged from the grid. A strategy with lengthinformation of the driving cycle from a global positioning system, GPS, couldreduce the cost of driving. This by starting to blend the electric energy with fuelearlier, a strategy called blended driving accomplish this by distribute the electricenergy, that is charged externally, with fuel over the driving cycle, and also ensurethat the battery’s minimum level reaches before the driving cycle is finished. Astrategy called Charge Depleting Charge Sustaining, CDCS, does not need lengthinformation. This strategy first depletes the battery to a minimum State of Charge,SOC, and after this engages the engine to maintain the SOC at this level. In thisthesis, a variable SOC reference is developed, which is dependent on knowledgeabout the cycle’s length and the current length the vehicle has driven in the cycle.With assistance of a variable SOC reference, is a blended strategy realized. Thisis used to minimize the cost of a driving cycle. A comparison between the blendedstrategy and the CDCS strategy was done, where the CDCS strategy uses a fixedSOC reference. During simulation is the usage of fuel minimized; and the blendedstrategy decreases the cost of the driving missions compared to the CDCS strategy.To solve the energy management problem is a model predictive control used. Thedesigned control system follows the driving cycles, is charge sustaining and solvesthe energy management problem during simulation. The system also handlesmoderate model errors. / Fordonsindustrin måste hantera allt strängare lagkrav mot utsläpp av emissioneroch växthusgaser. Hybridfordon har börjat betraktas som den framtida vägenför att ytterligare minska utsläpp och användning av fossila bränslen. Den ökadekomplexiteten från flera olika motorer kräver mera avancerade styrsystem. Begränsningarfrån motorernas energikällor gör att framtida förhållanden är viktigaatt estimera. För plug-in hybridfordon, PIHEV, är det viktigt att använda denvvijämförelsevis billiga elektriska energin innan fordonet har nått fram till slutdestinationen.Batteriets nuvarande energimängd mäts i dess State of Charge, SOC.Genom att utnyttja information om hur långt det är till slutdestinationen från ettGlobal Positioning System, GPS, blandar styrsystemet den elektriska energin medbränsle från början, detta kallas för blandad körning. En strategi som inte hartillgång till hur långt fordonet ska köras kallas Charge Depleting Charge Sustaining,CDCS. Denna strategi använder först energin från batteriet, för att sedanbörja använda förbränningsmotorn när SOC:s miniminivå har nåtts. Strategin attanvända GPS informationen är jämförd med en strategi som inte har tillgång tillinformation om körcykelns längd. Blandad körning använder en variabel SOC referens,till skillnad från CDCS strategin som använder sig av en konstant referenspå SOC:s miniminivå. Den variabla SOC referensen beror på hur långt fordonethar kört av den totala körsträckan, med hjälp av denna realiseras en blandad körning.Från simuleringarna visade det sig att blandad körning gav minskad kostnadför de simulerade körcyklerna jämfört med en CDCS strategi. En modellbaseradprediktionsreglering används för att lösa energifördelningsproblemet. Styrsystemetföljer körcykler och löser energifördelningsproblemet för de olika drivkällorna undersimuleringarna. Styrsystemet hanterar även måttliga modellfel.
186

Modeling and Control of Friction Stir Welding in 5 cm thick Copper Canisters / Modellering och Reglering av Friction Stir Welding i 5 cm tjocka Kopparkapslar

Nielsen, Isak January 2012 (has links)
Friction stir welding has become a popular forging technique used in many applications. The Swedish Nuclear Fuel and Waste Management Company (SKB) evaluates this method to seal the 5 cm thick copper canisters that will contain the spent nuclear fuel. To produce repetitive, high quality welds, the process must be controlled, and today a cascade controller is used to keep the desired stir zone temperature. In this thesis, the control system is extended to also include a plunge depth controller. Two different approaches are evaluated; the first attempt is a decentralized solution where the cascaded temperature controller is kept, and the second approach uses a non-linear model predictive controller for both depth and temperature. Suitable models have been derived and used to design the controllers; a simpler model for the decentralized control and a more extensive, full model used in the non-linear model predictive controller that relates all the important process variables. The two controller designs are compared according to important performance measures, and the achieved increase in performance with the more complex non-linear model predictive controller is evaluated. The non-linear model predictive controller has not been implemented on the real process. Hence, simulations of the closed loop systems using the full model have been used to compare and evaluate the control strategies. The decentralized controller has been implemented on the real system. Two welds have been made using plunge depth control with excellent experimental results, confirming that the decentralized controller design proposed in this thesis can be successfully used. Even though the controller manages to regulate the plunge depth with satisfying performance, simulations indicate that the non-linear model predictive controller achieves even better closed loop performance. This controller manages to compensate for the cross-connections between the process variables, and the resulting closed loop system is almost decoupled. Further research will reveal which control design that will finally be used. / ''Friction stir welding'' har blivit en populär svetsmetod inom många olika tillämpningar. På Svensk Kärnbränslehantering AB (SKB) undersöks möjligheten att använda metoden för att försegla de 5 cm tjocka kopparkapslarna som kommer innehålla det använda kärnbränslet. För att kunna producera repeterbara svetsar utav hög kvalité krävs det att processen regleras. Idag löses detta med en temperaturregulator som reglerar svetszonens temperatur. I detta examensarbete utökas styrsystemet med en regulator för svetsdjupet. Två olika lösningar har utvärderats; först en decentraliserad lösning där temperatur-regulatorn behålls och sedan en lösning med en olinjär modellprediktiv reglering (MPC) som reglerar både djup och temperatur. Passande modeller har tagits fram och har använts för att designa regulatorerna; en enklare modell för den decentraliserade regulatorn och en utökad, komplett modell som används i den olinjära MPC:n och som beskriver alla viktiga variabler i processen. Viktiga prestandamått har jämförts för de båda regulatorstrukturerna och även prestandaökningen med den olinjära MPC:n har utvärderats. Då denna regulator inte har implementerats på den verkliga processen har simuleringar av den kompletta modellen använts för att jämföra och utvärdera regulatorstrukturerna. Den decentraliserade regulatorn har implementerats och testats på processen. Två svetsar har gjorts och de har givit utmärkta resultat, vilket visar att regulatorstrukturen som presenteras i rapporten fungerar bra för reglering av svetsdjupet. Trots att den implementerade regulatorn klarar av att reglera svetsdjupet med godkänt resultat, så visar simuleringar att den olinjära MPC:n ger ännu bättre reglerprestanda. Denna regulator kompenserar för korskopplingar i systemet och resulterar i ett slutet system som är nästan helt frikopplat. Ytterligare forskning kommer avgöra vilken av strategierna som kommer att användas i slutprodukten.
187

Adaptive Cruise Control for Heavy Vehicles : Hybrid Control and MPC / Adaptiv farthållning för tunga fordon : hybrid reglering och MPC

Axehill, Daniel, Sjöberg, Johan January 2003 (has links)
An Adaptive Cruise Controller (ACC) is an extension of an ordinary cruise controller. In addition to maintaining a desired set velocity, an ACC can also maintain a desired time gap to the vehicle ahead. For this end, both the engine andthe brakes are controlled. The purpose with this thesis has been to develop control strategies for an ACC used in heavy vehicles. The focus of the work has been the methods used for switching between the use of engine and brake. Two different methods have been studied, a hybrid controller and an MPC-controller. For the hybrid controller, the main contribution has been to use the influence of the surroundings on the acceleration of the truck. This consists of several parts such as wind drag, road slope and rolling resistance. The estimated influence of the surroundings is used as a switch point between the use of engine and brakes. Ideally, these switch points give bumpless actuator switches. The interest in the MPC-controller as an alternative solution was to achieve automatic actuator switching, thus with no explicitly defined switch points. The MPC-controller is based on a model of the system including bounds on the control signals. Using this knowledge, the MPC-controller will choose the correct actuator for the current driving situation. Results from simulations show that both methods solve the actuator switch problem. The advantages with the hybrid controller are that it is implementable in a truck with the hardware used today and that it is relatively simple to parameterise. A drawback is that explicit switch points between the uses of the different actuators have to be included. The advantages with the MPC-controller are that no explicit switch points have to be introduced and that constraints and time delays on signals in the system can be handled in a simple way. Among the drawbacks, it can be mentioned that the variant of MPC, used in this thesis, is too complex to implement in the control system currently used in trucks. One further important drawback is that MPC demands a mathematical model of the system.
188

Control of Torsionalpendulum on Containercranes / Reglering av torsionspendel på containerkranar

Bäck, Pär January 2004 (has links)
A container crane of STS-type, Ship To Shore, consists of a spreader hanging underneath a railrunning trolly. As the container is under the influence of wind, it is likely that it starts to turn in a torsional pendulum. This report handles how the torsional pendulum of a container crane can be damped. A number of different models have been developed to analyze how different placement of the actuators affects the system. Two differens types of controllers, LQG and MPC, have been developed and applied to these models. The different models and controlers were evaluated and compared by studying simulation results in timedomain. Moreover in order to make the simulations more realistic, a wind model has been developed and applied. The models and controllers have been analyzed with bodediagrams and sensitivity functions. The analyses shows clearly that the best placement of the actuators for control of the torsional pendulum on an STS-crane is in the trolly, pulling and relaxing the wires. This control is best handled by a state feedback control (LQG). Furthermore, the control should in this way, with addition of in the horizontalplane movable suspensions in the trolly, work acceptably in the whole operational area of a STS-crane.
189

Controle multivariável aplicado a uma coluna de alta pureza com recompressão de vapor.

EMERENCIANO, Mariângela da Silva Araújo. 02 February 2018 (has links)
Submitted by Gustavo Nascimento (gustavo.diniz@ufcg.edu.br) on 2018-02-02T12:22:34Z No. of bitstreams: 1 MARIÂNGELA DA SILVA ARAÚJO EMERENCIANO - TESE PPGEQ 2014.pdf: 2549347 bytes, checksum: 4f7d187e940acf4a6dcad840f1d5c392 (MD5) / Made available in DSpace on 2018-02-02T12:22:34Z (GMT). No. of bitstreams: 1 MARIÂNGELA DA SILVA ARAÚJO EMERENCIANO - TESE PPGEQ 2014.pdf: 2549347 bytes, checksum: 4f7d187e940acf4a6dcad840f1d5c392 (MD5) Previous issue date: 2014-12-17 / Capes / Os processos industriais são sistemas multivariáveis (MIMO) que consistem de múltiplas variáveis de entrada e múltiplas variáveis de saída, onde a interação entre essas variáveis é uma característica inerente desses processos. A identificação do modelo nesse tipo de processo é uma etapa importante na implementação do sistema de controle, principalmente quando se trata de controladores MPC, os quais incorporam um modelo explícito do processo. O procedimento de identificação realizado neste trabalho propõe uma abordagem diferente da que se tem visto na literatura. Enquanto o mais comum é estimular as variáveis manipuladas, a nova abordagem proposta visa estimular o processo a partir de perturbações nos setpoints das variáveis controladas, em malha fechada, com o intuito de se obter uma melhor avaliação dos efeitos das variáveis controladas e manipuladas. A proposta deste trabalho é comparar duas estratégias de controle: uma estratégia de controle clássico e uma estratégia de controle multivariável baseado em modelo (MPC). O estudo de caso é uma coluna de separação propeno/propano de alta pureza com recompressão de vapor. Quando comparado o controle descentralizado com o controle MPC, observa-se que o MPC apresenta melhores resultados, afirmação esta, baseada nos valores do índice de desempenho IAE (Integral Absolute Error) para as duas propostas analisadas. / Industrial processes are multivariable systems (MIMO) consisting of multiple input variables and multiple output variables, where the interaction between these variables is an inherent characteristic of these processes. The model identification in this type of process is an important step in the implementation of the control system, especially when it comes to MPC controllers, which incorporate an explicit process model. The identification procedure performed in this research proposes a different approach to what has been seen in the literature. While the most common is to stimulate the manipulated variables, the proposed new approach aims to stimulate the process from disturbances in the setpoints of the controlled variables, closed loop, in order to obtain a better assessment of the effects of controlled and manipulated variables. The purpose of this study is to compare two control strategies: A classic control strategy and a multivariable control strategy based on model (MPC). The case study is a column separation of propylene / propane with high purity vapor recompression. When compared with the decentralized control the MPC control, it is observed that the MPC performs better, this statement, based on the values of IAE performance index (Integral Absolute Error) for the two proposals analyzed.
190

Studium av Othellospelande program : Design, algoritmer och implementation / A study of strong Othello programs : Design, algorithms and implementation

Ekbom, Andreas January 2003 (has links)
Att "smarta" brädspelande datorprogram har blivit mycket bättre under de senaste årtiondena har väl knappast kunnat undgå någon. Med brädspel menar jag spel såsom Go, Othello, Backgammon och Schack. Idag spelar program, som körs på en reguljär PC, bättre än de flesta människor. Vad är det som gör dessa program så bra? Hur kan man lära en dator att spela ett så pass komplext spel som Othello på en sådan nivå att ingen människa har en chans att vinna? I detta examensarbete kommer jag att försöka förklara mekanismerna bakom ett toppspelande Othelloprogram. Jag har dessutom implementerat ett eget Othellospelande program som jag använt som testapplikation för att prova olika sökmetoder, metoder för att öka exekveringshastigheten och tekniker för att öka spelskickligheten. Jag kommer att presentera empiriska data där jag utvärderar och jämför flera andra program med mitt eget.

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