As information technology advances, so does the demand for power management of telecom and computing equipment. High efficiency and high power density are still the key technology drivers for power management for these applications. In order to save energy, in 2005, the U.S. Environmental Protection Agency (EPA) announced the first draft of its proposed revision to its ENERGY STAR specification for computers. The draft specification separately addresses efficiency requirements for laptop, desktop, workstation and server computers. The draft specification also proposes a minimum power supply efficiency of 80% for PCs and 75% to 83% for desktop derived servers, depending on loading condition and server type. Furthermore, recently some industry companies came out with a much higher efficiency target for the whole AC/DC front-end converter over a wide load range. Distributed power systems are widely adopted in the telecom and computing applications for the reason of high performance and high reliability. As one of the key building blocks in distributed power systems, DC/DC converters in the front-end converter are also under the pressure of increasing efficiency and power density. Due to the hold-up time requirement, PWM DC/DC converters cannot achieve high efficiency for well known reasons when they are designed for wide input voltage range. As a promising topology for this application, LLC resonant converters can achieve both high efficiency and wide input voltage range capability because of its voltage gain characteristics and small switching loss. However, the efficiency of LLC resonant converter with diode rectifier still cannot meet the recent efficiency target from industry. In order to further improve efficiency of LLC resonant converters, synchronous rectification must be used. The complete solution of synchronous rectification of LLC resonant converters is discussed in this thesis. The driving of the synchronous rectifier can be realized by sensing the voltage Vds of the SR. The turn-on of the SR can be triggered by the body-diode conduction of the SR. With the Vds compensation network, the precise voltage drop on Rds_on can be achieved, thus the SR can be turned off at the right time. Moreover, efficiency optimization at normal operation over wide load range is discussed. It is revealed that power loss at normal operation is solely determined by the magnetizing inductance while the magnetizing inductor is designed according to dead-time td selection. The mathematic equations for the relationship between power loss and dead-time are developed. For the first time, the relationship between power loss and dead-time is used as a tool for efficiency optimization. With this tool, the efficiency optimization of the LLC resonant converter can be made according to efficiency requirement over a wide load range. With the expectation to achieve high efficiency at ultra-light load, the green mode operation of LLC resonant converters is addressed. The rationale of the issue with the conventional control algorithm is revealed and a preliminary solution is proposed. / Master of Science

No / Although ads with subtle racist imagery can reinforce negative stereotypes, advertisers can eliminate this problem. After a brief overview of predominantly U.S.-based research on the racial mix of models/actors in ads, a theoretical framework for unmasking subtle racial bias is provided and dimensional qualitative research (DQR) is introduced as a method for identifying and rectifying such ad imagery. Results of a DQR-based study of 622 U.K. television ads with at least one Black actor indicate (1) subtle racially biased imagery now supersedes overt forms, and (2) the most popular ad appeals often mask negative stereotypes. Implications for public policy and advertisers, as well as recommendations for future research, are discussed.

No / An algorithm for the rectification of uncalibrated images is presented and applied to a variety of cases. The algorithm generates the rectifying transformations directly from the geometrical relationship between the images, using any three correspondences in the images to define a reference plane. A small set of correspondences is used to calculate an initial rectification. Additional correspondences are introduced semi-automatically, by correlating regions of the rectified images. Since the rectified images of surfaces in the reference plane have no relative distortion, features can be matched very accurately by correlation, allowing small changes in disparity to be detected. In the 3-d reconstruction of an architectural scene, differences in depth are resolved to about 0.001 of the distance from camera to subject.

As a result of global warming, the prevalence of renewable energy sources such as wind farms has steadily increased over the last few decades. The wind industry is experiencing a push towards the offshore market, where wind speeds are higher and steadier, and wind farms can be co-located with areas of high populations, such as along the US East Coast. However, high wind and wave loading is proving costly for offshore developments, particularly floating structures such as semi-submersibles. Vibrations in the pitch and heave directions associated with greater yaw-bearing and tower-base bending moments, respectively, reduce the lifespan of these structures. This paper compares traditional tuned-mass dampers (TMDs) and tuned-mass damper inerters (TMDIs) with a nonlinear TMDI which utilizes a mechanical motion rectifier (MMR) to translate bidirectional to unidirectional motion of the primary generator shaft. The integration of the MMR system also permits the generator to disconnect from the tuned-mass damper inerter system when the generator is already spinning at a higher rate, thus providing potential to harvest additional energy from the vibration absorber. However, results show that the optimal nonlinear tuned-mass damper inerters results in near total engagement, reducing the efficacy of the system if optimal parameters can be feasibly sourced. The technology does show promise for situations where these optimal parameters cannot be attained, such as due to high stroke lengths and extremely low stiffnesses to correspond to the low platform frequencies. The development and preliminary testing of a 1/50th scale tuned-mass damper inerter prototype will be discussed; however, the full MMR system has yet to be integrated into the prototype. / Master of Science / As a result of global warming, the prevalence of renewable energy sources such as wind farms has steadily increased over the last few decades. The wind industry is experiencing a push towards the offshore market, where wind speeds are higher and steadier, and wind farms can be co-located with areas of high populations, such as the US East Coast. However, the cost of implementing this technology has presented a major challenge in the development of these structures. This paper discusses the application of a recent technology, nonlinear tuned-mass damper inerters (TMDIs), to absorb the vibrations associated with wave excitations on floating offshore wind platforms while also allowing disengagement of a generator shaft as needed to maximize generator speed and thus maximize energy harvesting potential. Results show comparable performance between the nonlinear TMDI and its more-common common tuned-mass damper (TMD) and linear TMDI counterparts in terms of vibration reduction and power performance. The integration of nonlinearity into the system may be best suited for slightly in-optimal parameters that are selected due to feasibility of sourcing and internal size constraints. The development and preliminary testing of a 1/50th scale TMDI prototype will all be discussed; however, development of nonlinearity in the TMDI system has yet to be integrated into the prototype.

This thesis deals with the task of three-dimensional scene reconstruction using image data obtained from multiple views. It is assumed that intrinsic parameters of the utilized cameras are known. The theoretical chapters describe the basic priciples of individual reconstruction steps. Variuous possible implementaions of data model suitable for this task are also described. The practical part also includes a comparison of false keypoint correspondence filtering, implementation of polar stereo rectification and comparison of disparity map calculation methods that are bundled with the OpenCV library. In the final portion of the thesis, examples of reconstructed 3D models are presented and discussed.

In this dissertation, I investigate the implications of libertarian morality in relation to the problem of climate change. This problem is explicated in the first chapter, where preliminary clarifications are also made. In the second chapter, I briefly explain the characteristics of libertarianism relevant to the subsequent study, including the central non-aggression principle. In chapter three, I examine whether our individual emissions of greenhouse gases, which together give rise to climate change, meet this principle. I do this based on the assumption that we are the legitimate owners of the resources we use in those activities. In the fourth chapter, I question this assumption and scrutinize libertarianism’s restrictions on appropriations of climate-relevant resources, which leads me to distinguish between some different versions of the libertarian view. Toward the end of the chapter, I also examine libertarianism’s answer to the political question regarding how emission rights should be distributed. The fifth chapter investigates libertarianism’s verdicts for mere risks of infringement, as stemming from people’s emissions and acts of appropriations. In chapter six, I investigate the libertarian right to self-defense against both the effects of climate change and other people’s climate-relevant activities. In chapter seven, I discuss two intergenerational issues related to climate change: what libertarianism says concerning future generations and how libertarianism might deal with the problem of historical emissions. The eighth chapter explores the implications of libertarianism regarding collective moral wrongdoing in connection to climate change. In chapter nine, I take a look at the libertarian room for governmental responses for tackling climate change. The tenth and final chapter is a summary. The overall conclusion of the dissertation is that libertarianism recommends that we reduce our emissions and decrease our extraction of natural resources such as forests and fossil fuels. Furthermore, governments are permitted to undertake some quite substantial actions in order to fight the causes of climate change. I end with some bottom-up reflections on what these conclusions might say about the plausibility of libertarianism. I claim that although libertarianism after all manages to explain some of our moral intuitions regarding climate change, it is questionable whether libertarianism’s explanation is better than those offered by alternative moral theories.

Heterogeneous mixtures have the potential to be used as synthetic substrates for antenna applications giving the antenna designer new degrees of freedom to control the permittivity and/or permeability in three dimensions such as by a smooth variation of the density of the inclusions, the height of the substrate and the manufacture the whole antenna system in one process. Electromagnetic, fabrication, environmental, time and cost advantages are potential especially when combined with nano-fabrication techniques. Readily available and cheap materials such as Polyethylene and Copper can be used in creating these heterogeneous materials. These advantages have been further explained in this thesis. In this thesis, the research presented is on canonical, numerical and measurement analysis on heterogeneous mixtures that can be used as substrates for microwave applications. It is hypothesised that heterogeneous mixtures can be used to design bespoke artificial dielectric substrates for say, patch antennas. The canonical equations from published literature describing the effective permittivity, ε_eff and effective permeability, μ_eff of heterogeneous mixtures have been extensively examined and compared with each other. Several simulations of homogenous and heterogeneous media have been carried out and an extraction/inversion algorithm applied to find their ε_eff and μ_eff. Parametric studies have been presented to show how the different variables of the equations and the simulations affect the accuracy of the results. The extracted results from the inversion process showed very good agreement with the known values of the homogenous media. Numerically and canonically computed values of ε_eff and μ_eff of various heterogeneous media were shown to have good agreement. The fabrication techniques used in creating the samples used in this research were examined, along with the different measurement methods used in characterising their electromagnetic properties via simulations and measurements. The challenges faced with these measurement methods were explained including the possible sources of error. Patch antennas were used to investigate how the performance of an antenna may be affected by heterogeneous media with metallic inclusions. The performance of the patch antenna was not inhibited by the presence of the metallic inclusions in close proximity. The patch measurement was also used as a measurement technique in determining the ε_eff of the samples.

Submitted by Maria Aparecida (cidazen@gmail.com) on 2017-09-25T12:30:39Z No. of bitstreams: 1 Tuanny.pdf: 67993195 bytes, checksum: 95028e53f0c6cf1e7ec70311b44782f8 (MD5) / Made available in DSpace on 2017-09-25T12:30:39Z (GMT). No. of bitstreams: 1 Tuanny.pdf: 67993195 bytes, checksum: 95028e53f0c6cf1e7ec70311b44782f8 (MD5) Previous issue date: 2015-03-30 / This paper analyzes the answers given by the Judiciary to the cases of name rectification and legal gender in the civil registry of transsexual people and travestis. The necessity of this study arises from the fact that the Brazilian legal system does not provide exceptions to situations where gender contrast with the information on identification documents, which is an experience that these individuals go through. On the opposite of what they are required to be, the transsexual people and the travestis live gender differently from the rules created in the context of heterosexism, which demand coherence and continuity among sex, gender and sexuality. The main objective consists of questioning the discourses produced in the juridical field by the magistrates responsible for the trial and consequently the ruling of these cases. To achieve that, this paper studies, through the analysis of documents and bibliographic reviews, some rulings that deal with the modification of data in the civil registry of transgenders. In the first chapter, the concepts of “discourse”, “power”, and “truth” are analyzed from the French Discourse Analysis point of view of Michel Foucault, presenting the ideas of Michel Miaille and Clemerson Merlin Clève with the purpose of understanding the discourse aspects of Law. In the second chapter, statements such as sex, gender, sexuality and transsexuality, are examined mainly through Judith Butler. In the third chapter, some rules that deal with the right to have a name, as well as the possibilities and the ways of modifying information from the civil registry are investigated. In addition, some Brazilian rulings related to this subject are analyzed through bibliographic review. In the end, the rulings given in the state of Maranhão are examined. The results of the research demonstrate that the state of Maranhão, contrasting with the national reality, has been partially given positive answers to the cases involving transsexual individuals, mainly through the recognition of the importance of the rectification to the travesties and the transsexual men and women who have not undergone the sex reassignment surgery. / O trabalho aborda as respostas dadas pelo Poder Judiciário para as demandas de retificação de nome e sexo jurídico no registro civil de sujeitos transexuais e travestis, uma vez que o ordenamento jurídico brasileiro não prevê exceções quando as expressões de gênero contrastarem com os atributos presentes nos documentos de identidade, experiência pela qual passam esses indivíduos. Ao contrário do que são interpelados a ser, as mulheres e homens transexuais e travestis vivenciam o gênero diferentemente das normas criadas no contexto do heterossexismo que exigem a coerência e continuidade entre sexo, gênero e sexualidade. A problemática consiste em indagar os discursos produzidos, no âmbito do campo jurídico, pelos magistrados responsáveis pelo julgamento desses casos. Abordamos os conceitos de “discurso”, “poder” e “verdade” a partir da Análise do Discurso de linha francesa, de base foucaultiana, dialogando com autores como Michel Miaille e Clémerson Merlin Clève com o objetivo de compreender os aspectos discursivos do Direito. A seguir, tratamos de enunciados como “sexo”, “gênero”, “sexualidade” e “transexualidade”, principalmente através de Judith Butler. Depois, examinamos algumas normativas acerca do direito ao nome, bem como as possibilidades e meios de alteração de dados do registro civil. Ao final, avaliamos, através de análise documental e revisão bibliográfica, algumas sentenças proferidas no estado do Maranhão. Os resultados da pesquisa demonstram que o estado do Maranhão, em parte, tem dado respostas positivas aos processos envolvendo sujeitos trans, principalmente pelo reconhecimento da importância da retificação para as travestis e para sujeitos transexuais não operados, contrastando com o contexto nacional.

In this thesis, sensitivity and error analysis of a differential rectification method were performed by using digital images taken by a frame camera onboard BILSAT and pushbroom scanner on ASTER. Three methods were implemented for Sensitivity and Uncertainty analysis: Monte Carlo, covariance analysis and FAST (Fourier Amplitude Sensitivity Test). A parameter estimation procedure was carried out on the basis of so called Mixed Model extended by some suitable additional regularization parameters to stabilize the solution for improper geometrical conditions of the imaging system. The effectiveness and accuracy of the differential rectification method were compared with other rectification methods and the results were analyzed. Furthermore the differential method is adapted to the pushbroom scanners and software which provides rectified images from raw satellite images was developed.

The aim of this thesis is to reconstruct 3D representation of underwater scenes from uncalibrated video sequences. Underwater visualization is important for underwater Remotely Operated Vehicles and underwater is a complex structured environment because of inhomogeneous light absorption and light scattering by the environment. These factors make 3D reconstruction in underwater more challenging. The reconstruction consists of the following stages: Image enhancement, feature detection and matching, fundamental matrix estimation, auto-calibration, recovery of extrinsic parameters, rectification, stereo matching and triangulation. For image enhancement, a pre-processing filter is used to remove the effects of water and to enhance the images. Two feature extraction methods are examined: 1. Difference of Gaussian with SIFT feature descriptor, 2. Harris Corner Detector with grey level around the feature point. Matching is performed by finding similarities of SIFT features and by finding correlated grey levels respectively for each feature extraction method. The results show that SIFT performs better than Harris with grey level information. RANSAC method with normalized 8-point algorithm is used to estimate fundamental matrix and to reject outliers. Because of the difficulties of calibrating the cameras in underwater, auto-calibration process is examined. Rectification is also performed since it provides epipolar lines coincide with image scan lines which is helpful to stereo matching algorithms. The Graph-Cut stereo matching algorithm is used to compute corresponding pixel of each pixel in the stereo image pair. For the last stage triangulation is used to compute 3D points from the corresponding pixel pairs.