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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Development of a phase-by-phase, arrival-based, delay-optimized adaptive traffic signal control methodology with metaheuristic search

Shenoda, Michael 29 April 2014 (has links)
Adaptive traffic signal control is the process by which the timing of a traffic signal is continuously adjusted based on the changing arrival patterns of vehicles at an intersection, usually with the goal of optimizing a given measure of effectiveness. Herein, a methodology is developed in which the characteristics of a traffic signal cycle are optimized at the conclusion of every phase based on the arrival times of vehicles to an intersection, using stopped delay as the measure of effectiveness. This optimization is solved using metaheuristic search procedures, namely tabu search, and embedded in an algorithm in which current vehicle arrival times are detected, arrival patterns over a specified horizon are predicted, the traffic signal timing is optimized, and the timings are sent to a traffic signal controller. The methodology is shown to provide improvement in performance for a number of intersection configurations and traffic regimes over traditional forms of traffic signal control, and the metaheuristic search is demonstrated to significantly reduce the computation time for a solution as compared with other search procedures. / text
32

High performance façades for commercial buildings

Bader, Stefan 30 November 2010 (has links)
Due to the fact that construction, maintenance and operation of buildings consume almost 50% of the energy today, architects play a major role in the reduction of energy consumption. The building’s envelope (façades and roof) can have a significant and measurable impact. With regard to overheating and the potential lost of internal heat, transparent parts of the building envelope have a large effect on the building’s energy consumption. Modern, transparent façade systems can fulfill contemporary demands, such as energy conservation, energy production or the degree of visual contact, of sustainable buildings in order to reduce internal heating, cooling, and electrical loads. An analysis of existing shading devices and façade design leads to a comparative analysis of conventional shading devices like horizontal and vertical blinds as well as eggcrate and honeycomb shading structures in a hot-humid climate like Austin, Texas. This study helped evaluating strengths and weaknesses of each device resulting in an optimization process of conventional shading devices. Ultimately, an optimized shading structure has been developed. This project aimed to develop an advanced transparent façade system for a south-oriented commercial façade in Austin, Texas, which fulfills high standards with regard to low energy use, by limiting cooling loads and demands for artificial lighting while avoiding glare and heat losses during the cold season. The optimization has been achieved in providing full shading for a specified period of time throughout the year while providing maximized solar exposure. The shading structure consists out of an array of fixed shading components varying in size and proportion to fulfill criteria like specific views, transparency and aesthetics. The shading structure has been compared to conventional shading devices and analyzed with regard to the reduction of annual solar radiation. The improvement in design and energy consumption contributes to the variety of shading structures for building skins. It is anticipated that the solutions will help to widen the options for aesthetically pleasing, high-performance façades for commercial buildings. / text
33

CUSTOM DESIGNED MHC BINDING PEPTIDES FOR CANCER IMMUNOTHERAPY

Myers, Cheryl Eleanor January 2009 (has links)
Cancer immunotherapy seeks to boost the host’s immune system to respond to tumor antigens. The adaptive immune system comprises of two arms, one that elicits a cellular immune response and one that elicits a humoral immune response. Cytotoxic T lymphocytes (CTL) recognize short antigenic peptides presented to them in the context of class I major histocompatibility complex (MHC) molecules and are capable of killing tumor cells. CTL are educated to discriminate between foreign and self-antigen. Tumors frequently express self-antigen which usually makes them poorly immunogenic. Because tumors are genetically unstable, they may present excess self peptides and/or peptides in a reading frame different from wild type self proteins. These frameshift (FS) peptides, are caused by an insertion or deletion of nucleotides that disrupt translation of the normal reading frame and alters the protein produced such that it is non-self. Binding affinity, dissociation rate and the overall stability of the peptide/MHC/β₂-microglobulin complex are important considerations in determining the immunogenicity of a given peptide. Interaction between the anchor residues in a peptide and binding pockets in MHC are essential, but this interaction is not always strong enough to stimulate T cell responses. This indicates that not all amino acids of the peptide ligand bound to MHC are equally important for the functional outcome of the receptor engagement and that other amino acid residues in the sequence are important for binding. Optimized peptide ligands (OPL) are analogues derived from natural wild type antigenic peptides that contain amino acid substitutions at anchor and auxiliary residues. OPL can be rationally designed to generate a more robust immune response compared to that of the wild-type peptide. Active immunotherapy using OPL of tumor antigen epitopes are designed to elicit tumor-specific CTL that can overcome tolerance and either re-awaken or elicit new T-cell responses to an antigen. The work and principles presented here using brain tumor-derived peptides demonstrates that HLA-A*0201-restricted CTL generated against wild type, frameshift and OPL peptides elicit CTL that were able to recognize and respond to wild type, tumorderived peptides. The response was donor dependent in that not all individuals responded more strongly to OPL; a minority responded better to wild type peptide. This data further suggests that the rational design and testing of multiple peptides for the same epitope should elicit a broader response among different individuals than single peptide immunization.
34

ENHANCING LACOME TO CONSIDER PRIVACY AND SECURITY ISSUES

Dhillon, Sukhveer 22 February 2013 (has links)
LACOME, the Large Collaborative Meeting Environment, is a collaboration system that allows multiple users to simultaneously publish their computer desktops (workspace) and/or windows on a large shared display via a network connection. Once published, windows or even full desktops can be moved, resized, and iconified; optionally, users can even interact with the content of other users. LACOME was originally designed and developed at The University of British Columbia; we extend the system to consider privacy and security concerns. We conducted a series of focus groups to obtain feedback on the initial design of the system. Based on our findings, we developed high level design requirements for future iterations of LACOME; these include the need for addressing privacy and security concerns when moving from the use of LACOME in a co-located setting to the overarching goal of its use in a mixed presence environment. We implemented new features that provide enhanced awareness of users’ shared workspaces and the interactions of others with them. We also developed an access control framework in the system that allows users to assign permissions on an ad-hoc basis. We undertook an initial evaluation of the LACOME system to evaluate the overall system and the changes that we made to it.
35

Controle de frequência para otimização da potência em um sistema de transmissão de energia sem fios

Diniz Junior, Walter Ferreira January 2017 (has links)
Nesse trabalho é apresentada uma estratégia de controle para manter a potência entregue a carga do link indutivo de um sistema de transferência de potência sem fios maximizada continuamente. Inicialmente, foi desenvolvido o modelo do link indutivo do sistema, de forma a encontrar uma expressão para a potência na carga. Em seguida, essa expressão foi analisada, buscando os pontos de potência máxima correspondentes às frequências ressonantes quando o fator de acoplamento magnético do link indutivo era variado. Assim, foi estabelecido um método para estimar esse fator de acoplamento k e consequentemente da indutância mútua M a partir do monitoramento direto da fase e do módulo da corrente de entrada do link e indireto da impedância de entrada. Portanto, a estratégia de controle proposta consiste em monitorar a corrente da fonte de entrada do link para estimar o fator de acoplamento magnético k e finalmente, sintonizar a fonte na frequência de ressonância associada ao coeficiente de acoplamento magnético pela função obtida fres(k). Os resultados experimentais mostraram que a estratégia proposta aumenta significativamente a potência entregue a carga em comparação a uma fonte de alimentação sintonizada em uma frequência fixa. / A control strategy is presented in this work to maintain the power delivered to a load continuously maximized at the output of a wireless power transfer system. Initially, the inductive link model of the system was developed in order to find an expression for the power delivered to the load. Thus, the maximum power delivered to the load points were obtained experimentally while the magnetic coupling factor of the inductive link was varied and associated with the frequency of the source. The frequency and magnetic coupling variables were related to the maximum power on the load by a simple analytic function. Thus, a method has been established to estimate the coupling factor k and consequently the mutual inductance M by direct monitoring of the phase and the module of the input current of the link and indirect monitoring of the input impedance. Therefore, the proposed control strategy is to monitor the current of the input source of the link to estimate the magnetic coupling factor k and finally to tune the source at the resonance frequencies associated to the magnetic coupling coefficient by the obtained function fres(k). The experimental results showed that the proposed strategy increases significantly the power delivered to the load compared to a power source tuned at a fixed frequency.
36

Controle de frequência para otimização da potência em um sistema de transmissão de energia sem fios

Diniz Junior, Walter Ferreira January 2017 (has links)
Nesse trabalho é apresentada uma estratégia de controle para manter a potência entregue a carga do link indutivo de um sistema de transferência de potência sem fios maximizada continuamente. Inicialmente, foi desenvolvido o modelo do link indutivo do sistema, de forma a encontrar uma expressão para a potência na carga. Em seguida, essa expressão foi analisada, buscando os pontos de potência máxima correspondentes às frequências ressonantes quando o fator de acoplamento magnético do link indutivo era variado. Assim, foi estabelecido um método para estimar esse fator de acoplamento k e consequentemente da indutância mútua M a partir do monitoramento direto da fase e do módulo da corrente de entrada do link e indireto da impedância de entrada. Portanto, a estratégia de controle proposta consiste em monitorar a corrente da fonte de entrada do link para estimar o fator de acoplamento magnético k e finalmente, sintonizar a fonte na frequência de ressonância associada ao coeficiente de acoplamento magnético pela função obtida fres(k). Os resultados experimentais mostraram que a estratégia proposta aumenta significativamente a potência entregue a carga em comparação a uma fonte de alimentação sintonizada em uma frequência fixa. / A control strategy is presented in this work to maintain the power delivered to a load continuously maximized at the output of a wireless power transfer system. Initially, the inductive link model of the system was developed in order to find an expression for the power delivered to the load. Thus, the maximum power delivered to the load points were obtained experimentally while the magnetic coupling factor of the inductive link was varied and associated with the frequency of the source. The frequency and magnetic coupling variables were related to the maximum power on the load by a simple analytic function. Thus, a method has been established to estimate the coupling factor k and consequently the mutual inductance M by direct monitoring of the phase and the module of the input current of the link and indirect monitoring of the input impedance. Therefore, the proposed control strategy is to monitor the current of the input source of the link to estimate the magnetic coupling factor k and finally to tune the source at the resonance frequencies associated to the magnetic coupling coefficient by the obtained function fres(k). The experimental results showed that the proposed strategy increases significantly the power delivered to the load compared to a power source tuned at a fixed frequency.
37

Avaliação da operação otimizada de usinas hidrelétricas / Evaluation of the optimized operation of hydroelectric power plants

Renato Mendes da Silva 12 December 2003 (has links)
Através da análise de estudos de otimização e simulação, considerando a operação energética das usinas existentes na cascata do rio Paranapanema, situada na região sudoeste do estado de São Paulo, mostrou-se que a operação do sistema, baseada em regras de operação obtidas através da otimização da cascata, resulta em ganhos significativos de geração e de energia armazenada, proporcionando, desse modo, uma melhor utilização de recursos hidrológicos, bem como uma condição final de armazenamento mais favorável, implicando uma operação mais eficiente e confiável de todo o sistema. / Through the analysis of optimization and simulation studies regarding the energy operation of the existing plants in the Paranapanema river, situated in the southwestern region of the state of São Paulo, Brazil, it was shown that the system operation, based on operation rules achieved considering the cascate optimization, yields significant gains of generation and stored energy in the system, therefore providing a better use of the available hydrologic resources, as well as a more favorable final storage level for each plant, which implies in a more efficient and reliable operation of the whole set.
38

Concepção otimizada de semi-submersíveis visando oscilações verticais mínimas sob excitação de ondas. / Semi-submersible optimized conception aiming heave under sea waves excitation.

Arnstein Hosaas 13 April 2007 (has links)
Plataformas semi-submersíveis, utilizadas como estruturas flutuantes na prospecção e exploração de petróleo em águas profundas, têm sua geometria composta basicamente por elementos horizontais totalmente submersos (pontoons), pelo convés, e por elementos verticais que cruzam a superfície livre (colunas), estes últimos ligando os pontoons ao convés. Tal geometria é eficaz para manter reduzidas as oscilações sob a ação de ondas, mormente o heave, bem como para prover flutuação, área de convés e estabilidade estática compatíveis com a missão. Neste trabalho aplicam-se modelos bastante simplificados para representação de características geométricas e dos atributos acima mencionados. De fato, pontoons e colunas são representados por trechos de cilindros, enquanto que as oscilações sob ondas são determinadas a partir de formulação semelhante à Equação de Morison. Tais modelos compõem um processo de otimização para determinar dimensões principais e proporções que satisfaçam certos requisitos quanto ao peso, à área de convés, à estabilidade estática e ao heave. Resultados numéricos para as oscilações sob ondas são confrontados com dados experimentais obtidos para plataformas em escala reduzida ensaiadas no canal de ondas do Laboratório de Engenharia Naval e Oceânica da EPUSP, observando-se boa aproximação. O processo de otimização é aplicado a situações descritas na literatura, chegando-se a resultados compatíveis com aqueles publicados, com a vantagem da simplicidade dos modelos analítico-numéricos aqui adotados. / Semi-submersible platforms, which are used as floating structures for oil production and exploration in deep waters, have their geometry composed basically of totally submerged horizontal elements (pontoons), the deck, and vertical elements that cross the free surface, these latter linking the pontoons to the deck. This geometry is efficient for keeping the oscillations due to wave excitation at small levels, specially the heave, as well to provide floatation, deck area and static stability compatible to the platform?s mission. In the present work, rather simplified models are applied for the representation of the geometric characteristics and of the other above mentioned attributes. In fact, pontoons and columns are represented by cylinders, and oscillations due to waves are determined by a formulation similar to Morison?s equation. These models take part in an optimization process for the determination of the main dimensions and proportions that satisfy certain requirements concerning weight, deck area, static stability and the heave. Numerical results for the oscillations due to waves are compared to experimental data obtained for scaled platforms tested in the wave channel of the Naval and Oceanic Engineering Laboratory of EPUSP, leading to reasonable approximations. The optimization process is applied to some cases described in the Literature, leading to results compatible with the published ones, but with the advantage of the simplicity of the analytic-numerical models here adopted.
39

Adapting an FPGA-optimized  microprocessor to the MIPS32 instruction set / Anpassning av en FPGA-optimerad processor till  instruktionsuppsättningen MIPS32

Andersson, Olof, Bengtsson, Karl January 2010 (has links)
Nowadays, FPGAs are large enough to host entire system-on-chip designs, wherein a soft core processor is often an integral part. High performance of the processor is always desirable, so there is an interest in finding faster solutions.This report aims to describe the work and results performed by Karl Bengtson and Olof Andersson at ISY. The task was to continue the development of a soft core microprocessor, originally created by Andreas Ehliar. The first step was to decide a more widely adopted instruction set for the processor. The choice fell upon the MIPS32 instruction set. The main work of the project has been focused on implementing support for MIPS32, allowing the processor to execute MIPS assembly language programs. The development has been done with speed optimization in mind. For every new function, the effects on the maximum frequency has been considered, and solutions not satisfying the speed requirements has been abandoned or revised.The performance has been measured by running a benchmark program—Coremark. Comparison has also been made to the main competitors among soft core processors. The results were positive, and reported a higher Coremark score than the other processors inthe study. The processor described herein still lacks many essential features. Nevertheless, the conclusion is that it may be possible to create a competitive alternative to established soft processors. / FPGAer används idag ofta för stora inbyggda system, i vilka en mjuk processor ofta spelar en viktig roll. Hög prestanda hos processorn är alltid önskvärt, så det finns ett intresse i att hitta snabbare lösningar. Denna rapport skall beskriva det arbete och de resultat som uppnåtts av Karl Bengtson och Olof Andersson på ISY. Uppgiften var att fortsätta utvecklandet av en mjuk processor, som ursprungligen skapats av Andreas Ehliar. Första steget var att välja ut en mer allmänt använd instruktionsuppsättning för processorn. Valet föll på instruktionsuppsättningsarkitekturen MIPS32. Projektets huvutarbete har varit fokuserat på att implementera stöd för MIPS32, vilket ger processorn möjlighet att köra assemblerprogram för MIPS.Utvecklingen har gjorts med hastighetsoptimering i beaktning. För varje ny funktion har dess effekter på maxfrekvensen undersökts,och lösningar som inte uppfyllt hastighetskraven har förkastats eller reviderats. Prestandan har mätts med programmet Coremark. Det har också gjorts jämförelser med huvudkonkurrenterna bland mjuka processorer. Resultaten var positiva, och rapporterade ett högre Coremarkpoäng än de andra processorerna i studien. Slutsatsen är att det ärmöjligt att skapa ett alternativ till de etablerade mjuka processorerna, men att denna processor fortfarande saknar väsentliga funktioner som behövs för att utgöra en mogen produkt.
40

Low Overhead Ethernet Communication for Open MPI on Linux Clusters

Hoefler, Torsten, Reinhardt, Mirko, Mietke, Frank, Mehlan, Torsten, Rehm, Wolfgang 20 July 2006 (has links) (PDF)
This paper describes the basic concepts of our solution to improve the performance of Ethernet Communication on a Linux Cluster environment by introducing Reliable Low Latency Ethernet Sockets. We show that about 25% of the socket latency can be saved by using our simplified protocol. Especially, we put emphasis on demonstrating that this performance benefit is able to speed up the MPI level communication. Therefore we have developed a new BTL component for Open MPI, an open source MPI-2 implementation which offers with its Modular Component Architecture a nearly ideal environment to implement our changes. Microbenchmarks of MPI collective and Point-to-Point operations were performed. We see a performance improvement of 8% to 16% for LU and SP implementations of the NAS parallel benchmark suite which spends a significant amount of time in the MPI. Practical application tests with Abinit, an electronic structure calculation program, show that the runtime of be nearly halved on a 4 node system. Thus we show evidence that our new Ethernet communication protocol is able to increase the speedup of parallel applications considerably.

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