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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.
11

Quantum codes over Finite Frobenius Rings

Sarma, Anurupa 2012 August 1900 (has links)
It is believed that quantum computers would be able to solve complex problems more quickly than any other deterministic or probabilistic computer. Quantum computers basically exploit the rules of quantum mechanics for speeding up computations. However, building a quantum computer remains a daunting task. A quantum computer, as in any quantum mechanical system, is susceptible to decohorence of quantum bits resulting from interaction of the stored information with the environment. Error correction is then required to restore a quantum bit, which has changed due to interaction with external state, to a previous non-erroneous state in the coding subspace. Until now the methods for quantum error correction were mostly based on stabilizer codes over finite fields. The aim of this thesis is to construct quantum error correcting codes over finite Frobenius rings. We introduce stabilizer codes over quadratic algebra, which allows one to use the hamming distance rather than some less known notion of distance. We also develop propagation rules to build new codes from existing codes. Non binary codes have been realized as a gray image of linear Z4 code, hence the most natural class of ring that is suitable for coding theory is given by finite Frobenius rings as it allow to formulate the dual code similar to finite fields. At the end we show some examples of code construction along with various results of quantum codes over finite Frobenius rings, especially codes over Zm.
12

Tillämpning av effektstabilisering i PLC

Andersson, Stefan, Johansson, Andreas January 2008 (has links)
Syftet med examensarbetet är att digitalt tillämpa en stabilisering av pendlingar i den aktiva effekten hos en synkrongenerator för vattenkraft kopplad till ett distributionsnät. Implementeringen är tänkt att ske i en PLC som redan hanterar andra delar av magnetiseringen. Effektstabiliseringen görs genom att en motverkande styrsignal skickas till magnetiseringsutrustningen vilken i sin tur påverkar generatorns uteffekt. Denna motverkande styrsignal kan tas fram på olika sätt. Två modeller, av IEEE standardiserade, för effektstabilisering undersöks, PSS1A och PSS2B. En Simulink-modell över ett distributionsnät med generator byggs upp för att testa effektstabiliseringen. Diskretisering av den ena standarden utförs för att digital implementering ska kunna ske. Tester utförs även på denna modell för att kunna validera dess funktion i jämförelse med den kontinuerliga. Den tidsdiskreta modellen görs om till ett matematiskt uttryck tillämpbart i PLC:n. Jämförelse sker mellan simuleringarna och den tillämpade modellen genom mätningar. / The purpose of the degree project is to make a digital realization of a stabilizer for oscillations in the active power from a hydropower synchronous generator, connected to a power network. The implementation is supposed to be done in a PLC which already handles part of the excitation system. The power stabilization is achieved by sending a counteracting reference signal to the excitation system which controls the generator’s output power. This counteracting signal can be achieved in several ways. Two existing models, standardized by IEEE, for power system stabilizing will be examined, PSS1A and PSS2B. A Simulink-model of a distribution net with a generator is constructed to test the stabilizers. To perform a digital implementation a discrete transformation of one continuous model is done. This discrete model is also tested to verify the function in comparison to the continuous one. The discrete model is reorganized in a form possible to implement in the PLC. Comparison between the simulated and the implemented model is made by measurement.
13

Estudo reológico de formulações para sorvetes produzidos com diferentes estabilizantes / Rheological study of ice cream formulations produced with different food stabilizers

Milliatti, Mariana Carniel 22 April 2013 (has links)
Seis formulações para sorvete foram produzidas com diferentes combinações entre os estabilizantes alimentícios Goma Guar, Goma Locusta (LBG) e Gelatina e foram avaliadas durante diferentes etapas de produção: maturação, após batimento e congelamento e após congelamento total. Através dos testes ocilatórios identificou-se que as misturas para sorvetes produzidas com a combinação de Gelatina com Goma Guar e Gelatina com LBG apresentam forte relação entre tempo de maturação e propriedade reológica, o que não foi observado nas formulações contendo cada um dos estabilizantes isoladamente, e nem na formulação contendo a mistura de LBG com Goma Guar. Isso mostra a existência de uma interação forte entre gelatina e galactomananas e que a maturação dessa mistura é essencial para a formação de uma rede contínua e estável. Após maturação de 24 horas, os sorvetes foram produzidos e analisados assim que saíram da produtora a -4°C. As análises conduzidas nesta etapa foram: capacidade de aeração (overrun) e força máxima requerida para extrusão. Quando dois estabilizantes foram combinados percebeu-se menor overrun o que pode ser explicado pelo aumento da viscosidade do sistema quando combinamos dois hidrocolóides, dificultando a incorporação de ar. Pôde ser percebida uma tendência de maior força necessária para extrusão para sorvetes com maior incorporação de ar. Tanto o tamanho dos cristais de gelo quanto o volume da fase congelada podem ter contribuído para aumento da dureza dos sorvetes. Após congelamento total dos sorvetes, a análise da varredura de freqüência realizada a -8ºC mostrou que os sorvetes produzidos com Gelatina e com a mistura LBG + Gelatina apresentaram maiores valores de G’ o que é um indicativo da presença de cristais de gelo maiores e também maior rigidez. Através da reologia termo-oscilatória, na faixa de temperatura de -10 a 5ºC, foi possível avaliar as modificações nas estruturas dos produtos e sua relação com as propriedades sensoriais. Entre -10ºC e -1ºC foi observado, para todas as formulações, um grande declínio nos módulos elástico (G’) e viscoso (G”) devido à perda das interações cooperativas entre os cristais de gelo, associada com o seu derretimento. Após derretimento, as formulações não variaram muito em relação ao parâmetro G”, que se relaciona com a cremosidade dos sorvetes durante consumo. / Six ice cream formulations were produced with different combinations of food stabilizers: Guar gum, Locust bean gum (LBG) and Gelatin. They were evaluated during different production steps: aging time, after whipping and freezing and after complete freezing. Oscillatory trials during aging time showed that ice cream mixes produced with Gelatin + Guar gum and Gelatin + LBG present strong relationship between aging time and rheologic properties, which was not observed in the formulations containing each of these stabilizers alone, nor in the formulations containing the combination of Guar gum + LBG. These results show the strong interaction between gelatin and galactomannans and, also, aging time is critical to create a continuous and stable network for this combination. After aging time (24 hours), the ice creams were produced and evaluated as soon as they were removed from the ice cream producer machine. The tests conducted this time were aeration capacity (overrun) and maximum force required for extrusion. The combination of two stabilizers produced ice creams with lower overrun, which can be explained by the higher viscosity of these systems, making them difficult to incorporate air. It was perceived a trend of greater force required for extrusion for the ice creams with greater incorporation of air. Both the size of the ice crystals as the volume of the frozen phase may have contributed to increase the hardness of these ice creams. After complete freezing, the ice creams were evaluated by a frequency sweep test at -8ºC. Ice creams produced with Gelatin and Gelatin + LBG presented higher G’ values, which is an indicative of larger ice crystals and also greater rigidity. Through the thermo-oscillatory rheology, between -10ºC and +5ºC, it was possible to evaluate the changes in the structures of the products and their relation to sensory properties. Between -10°C and -1°C it was observed, for all formulations, a large decline in the elastic and viscous modules (G’ and G”, respectively) due to the lost of the cooperative interactions among the ice crystals, associated with their melting. After melting, the parameter G”, associated with the creaminess of the ice cream was very similar for the six formulations evaluated.
14

Estudo reológico de formulações para sorvetes produzidos com diferentes estabilizantes / Rheological study of ice cream formulations produced with different food stabilizers

Mariana Carniel Milliatti 22 April 2013 (has links)
Seis formulações para sorvete foram produzidas com diferentes combinações entre os estabilizantes alimentícios Goma Guar, Goma Locusta (LBG) e Gelatina e foram avaliadas durante diferentes etapas de produção: maturação, após batimento e congelamento e após congelamento total. Através dos testes ocilatórios identificou-se que as misturas para sorvetes produzidas com a combinação de Gelatina com Goma Guar e Gelatina com LBG apresentam forte relação entre tempo de maturação e propriedade reológica, o que não foi observado nas formulações contendo cada um dos estabilizantes isoladamente, e nem na formulação contendo a mistura de LBG com Goma Guar. Isso mostra a existência de uma interação forte entre gelatina e galactomananas e que a maturação dessa mistura é essencial para a formação de uma rede contínua e estável. Após maturação de 24 horas, os sorvetes foram produzidos e analisados assim que saíram da produtora a -4°C. As análises conduzidas nesta etapa foram: capacidade de aeração (overrun) e força máxima requerida para extrusão. Quando dois estabilizantes foram combinados percebeu-se menor overrun o que pode ser explicado pelo aumento da viscosidade do sistema quando combinamos dois hidrocolóides, dificultando a incorporação de ar. Pôde ser percebida uma tendência de maior força necessária para extrusão para sorvetes com maior incorporação de ar. Tanto o tamanho dos cristais de gelo quanto o volume da fase congelada podem ter contribuído para aumento da dureza dos sorvetes. Após congelamento total dos sorvetes, a análise da varredura de freqüência realizada a -8ºC mostrou que os sorvetes produzidos com Gelatina e com a mistura LBG + Gelatina apresentaram maiores valores de G’ o que é um indicativo da presença de cristais de gelo maiores e também maior rigidez. Através da reologia termo-oscilatória, na faixa de temperatura de -10 a 5ºC, foi possível avaliar as modificações nas estruturas dos produtos e sua relação com as propriedades sensoriais. Entre -10ºC e -1ºC foi observado, para todas as formulações, um grande declínio nos módulos elástico (G’) e viscoso (G”) devido à perda das interações cooperativas entre os cristais de gelo, associada com o seu derretimento. Após derretimento, as formulações não variaram muito em relação ao parâmetro G”, que se relaciona com a cremosidade dos sorvetes durante consumo. / Six ice cream formulations were produced with different combinations of food stabilizers: Guar gum, Locust bean gum (LBG) and Gelatin. They were evaluated during different production steps: aging time, after whipping and freezing and after complete freezing. Oscillatory trials during aging time showed that ice cream mixes produced with Gelatin + Guar gum and Gelatin + LBG present strong relationship between aging time and rheologic properties, which was not observed in the formulations containing each of these stabilizers alone, nor in the formulations containing the combination of Guar gum + LBG. These results show the strong interaction between gelatin and galactomannans and, also, aging time is critical to create a continuous and stable network for this combination. After aging time (24 hours), the ice creams were produced and evaluated as soon as they were removed from the ice cream producer machine. The tests conducted this time were aeration capacity (overrun) and maximum force required for extrusion. The combination of two stabilizers produced ice creams with lower overrun, which can be explained by the higher viscosity of these systems, making them difficult to incorporate air. It was perceived a trend of greater force required for extrusion for the ice creams with greater incorporation of air. Both the size of the ice crystals as the volume of the frozen phase may have contributed to increase the hardness of these ice creams. After complete freezing, the ice creams were evaluated by a frequency sweep test at -8ºC. Ice creams produced with Gelatin and Gelatin + LBG presented higher G’ values, which is an indicative of larger ice crystals and also greater rigidity. Through the thermo-oscillatory rheology, between -10ºC and +5ºC, it was possible to evaluate the changes in the structures of the products and their relation to sensory properties. Between -10°C and -1°C it was observed, for all formulations, a large decline in the elastic and viscous modules (G’ and G”, respectively) due to the lost of the cooperative interactions among the ice crystals, associated with their melting. After melting, the parameter G”, associated with the creaminess of the ice cream was very similar for the six formulations evaluated.
15

Tillämpning av effektstabilisering i PLC

Andersson, Stefan, Johansson, Andreas January 2008 (has links)
<p>Syftet med examensarbetet är att digitalt tillämpa en stabilisering av pendlingar i den aktiva effekten hos en synkrongenerator för vattenkraft kopplad till ett distributionsnät.</p><p>Implementeringen är tänkt att ske i en PLC som redan hanterar andra delar av magnetiseringen.</p><p>Effektstabiliseringen görs genom att en motverkande styrsignal skickas till magnetiseringsutrustningen vilken i sin tur påverkar generatorns uteffekt. Denna motverkande styrsignal kan tas fram på olika sätt.</p><p>Två modeller, av IEEE standardiserade, för effektstabilisering undersöks, PSS1A och PSS2B.</p><p>En Simulink-modell över ett distributionsnät med generator byggs upp för att testa effektstabiliseringen.</p><p>Diskretisering av den ena standarden utförs för att digital implementering ska kunna ske. Tester utförs även på denna modell för att kunna validera dess funktion i jämförelse med den kontinuerliga.</p><p>Den tidsdiskreta modellen görs om till ett matematiskt uttryck tillämpbart i PLC:n.</p><p>Jämförelse sker mellan simuleringarna och den tillämpade modellen genom mätningar.</p> / <p>The purpose of the degree project is to make a digital realization of a stabilizer for oscillations in the active power from a hydropower synchronous generator, connected to a power network.</p><p>The implementation is supposed to be done in a PLC which already handles part of the excitation system.</p><p>The power stabilization is achieved by sending a counteracting reference signal to the excitation system which controls the generator’s output power. This counteracting signal can be achieved in several ways.</p><p>Two existing models, standardized by IEEE, for power system stabilizing will be examined, PSS1A and PSS2B.</p><p>A Simulink-model of a distribution net with a generator is constructed to test the stabilizers.</p><p>To perform a digital implementation a discrete transformation of one continuous model is done. This discrete model is also tested to verify the function in comparison to the continuous one.</p><p>The discrete model is reorganized in a form possible to implement in the PLC.</p><p>Comparison between the simulated and the implemented model is made by measurement.</p>
16

The Role of Glutathione Metabolism in the Neuroprotective Effect of Mood Stabilizers

Pasiliao, Clarissa 13 January 2011 (has links)
Several lines of evidence implicate oxidative stress in the pathophysiology of bipolar disorder (BPD). The mood stabilizers lithium and valproate have been shown to protect against oxidative stress-induced cell death. This study examined whether an increase in cellular reductive potential due to glutathione (GSH) synthesis up-regulation underlies this neuroprotective effect. Using primary rat cortical neurons as a model, this study demonstrated that unlike lithium and valproate, carbamazepine and lamotrigine do not exert neuroprotective effects against H2O2-induced cell death. Moreover, the level of GSH and the GSH:GSSG ratio in neurons and in rat brain remained unchanged following chronic treatment with either lithium or valproate. Similarly, this study did not find a significant effect of treatment on the expression of genes encoding γ-glutamylcysteine ligase sub-units, Gclc and Gclm, in both neurons and the rat brain. These findings suggest that other molecular targets of lithium and valproate likely mediate the observed neuroprotective effects.
17

Design Optimization and Verification of a Horizontal Stabilizer for the SeaStryder600 Wing-in-ground-Effect (WIG) Aircraft

Haley, Stephen 20 November 2012 (has links)
Aircraft manufacturer Aquavion Systems is currently designing and constructing prototypes for its revolutionary new fleet of aircraft called the SeaStryder. During the prototyping phase, it was discovered that the center-of-gravity of the SeaStryder600 was too far aft and outside of the acceptable range. To solve this design issue, it was hypothesized that the weight of the horizontal stabilizer may be reduced without compromising its structural integrity. The following document analyzes this hypothesis and provides two alternative designs. Each design exceeds the design requirements, meets additional requirements requested by industry, and provides a significant degree of weight savings. The first design provides a 25% weight reduction. The second design provides an 18% weight reduction as well as a 160% increase in loading capacity. The designs proposed have both been verified through the use of Finite Element Analysis as well as by means of experimentation where two prototype wings were constructed and tested to failure confirming the analytical results.
18

The Role of Glutathione Metabolism in the Neuroprotective Effect of Mood Stabilizers

Pasiliao, Clarissa 13 January 2011 (has links)
Several lines of evidence implicate oxidative stress in the pathophysiology of bipolar disorder (BPD). The mood stabilizers lithium and valproate have been shown to protect against oxidative stress-induced cell death. This study examined whether an increase in cellular reductive potential due to glutathione (GSH) synthesis up-regulation underlies this neuroprotective effect. Using primary rat cortical neurons as a model, this study demonstrated that unlike lithium and valproate, carbamazepine and lamotrigine do not exert neuroprotective effects against H2O2-induced cell death. Moreover, the level of GSH and the GSH:GSSG ratio in neurons and in rat brain remained unchanged following chronic treatment with either lithium or valproate. Similarly, this study did not find a significant effect of treatment on the expression of genes encoding γ-glutamylcysteine ligase sub-units, Gclc and Gclm, in both neurons and the rat brain. These findings suggest that other molecular targets of lithium and valproate likely mediate the observed neuroprotective effects.
19

Design Optimization and Verification of a Horizontal Stabilizer for the SeaStryder600 Wing-in-ground-Effect (WIG) Aircraft

Haley, Stephen 20 November 2012 (has links)
Aircraft manufacturer Aquavion Systems is currently designing and constructing prototypes for its revolutionary new fleet of aircraft called the SeaStryder. During the prototyping phase, it was discovered that the center-of-gravity of the SeaStryder600 was too far aft and outside of the acceptable range. To solve this design issue, it was hypothesized that the weight of the horizontal stabilizer may be reduced without compromising its structural integrity. The following document analyzes this hypothesis and provides two alternative designs. Each design exceeds the design requirements, meets additional requirements requested by industry, and provides a significant degree of weight savings. The first design provides a 25% weight reduction. The second design provides an 18% weight reduction as well as a 160% increase in loading capacity. The designs proposed have both been verified through the use of Finite Element Analysis as well as by means of experimentation where two prototype wings were constructed and tested to failure confirming the analytical results.
20

A functional link network based adaptive power system stabilizer

Srinivasan, Saradha 02 September 2011
<p>An on-line identifier using Functional Link Network (FLN) and Pole-shift (PS) controller for power system stabilizer (PSS) application are presented in this thesis. To have the satisfactory performance of the PSS controller, over a wide range of operating conditions, it is desirable to adapt PSS parameters in real time. Artificial Neural Networks (ANNs) transform the inputs in a low-dimensional space to high-dimensional nonlinear hidden unit space and they have the ability to model the nonlinear characteristics of the power system. The ability of ANNs to learn makes them more suitable for use in adaptive control techniques.</p> <p>On-line identification obtains a mathematical model at each sampling period to track the dynamic behavior of the plant. The ANN identifier consisting of a Functional link Network (FLN) is used for identifying the model parameters. A FLN model eliminates the need of hidden layer while retaining the nonlinear mapping capability of the neural network by using enhanced inputs. This network may be conveniently used for function approximation with faster convergence rate and lesser computational load.</p> <p>The most commonly used Pole Assignment (PA) algorithm for adaptive control purposes assign the pole locations to fixed locations within the unit circle in the z-plane. It may not be optimum for different operating conditions. In this thesis, PS type of adaptive control algorithm is used. This algorithm, instead of assigning the closed-loop poles to fixed locations within the unit circle in the z-plane, this algorithm assumes that the pole characteristic polynomial of the closed-loop system has the same form as the pole characteristic of the open-loop system and shifts the open-loop poles radially towards the centre of the unit circle in the z-plane by a shifting factor &alpha; according to some rules. In this control algorithm, no coefficients need to be tuned manually, so manual parameter tuning (which is a drawback in conventional power system stabilizer) is minimized. The PS control algorithm uses the on-line updated ARMA parameters to calculate the new closed-loop poles of the system that are always inside the unit circle in the z-plane.</p> <p>Simulation studies on a single-machine infinite bus and on a multi-machine power system for various operating condition changes, verify the effectiveness of the combined model of FLN identifier and PS control in damping the local and multi-mode oscillations occurring in the system. Simulation studies prove that the APSSs have significant benefits over conventional PSSs: performance improvement and no requirement for parameter tuning.</p>

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