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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.
21

Comparison between active and passive rectification for different types of permanent magnet synchronous machines

Örnkloo, Johannes January 2018 (has links)
When using an intermittent source of energy such as wind power together with a synchronous machine a frequency converter system is needed to decouple the generator from the grid, due to the fluctuations in wind speed resulting in fluctuating electrical frequency. The aim of this master's thesis is to investigate how different types of rectification methods affect permanent magnet synchronous machines of different saliency ratios. A literature study was carried out to review the research within the area and to acquire the necessary knowledge to carry out the work. Two simulation models were created that include a permanent magnet synchronous generator driven by a wind turbine and connected to the grid via a frequency converter, where one model utilizes active rectification and one utilizes passive rectification. The simulation models were verified by carrying out an experiment on a similar setup, which showed that the simulation results coincide well with the results of the experiment. The results of the simulation study were then used to compare the rectification systems as well as investigate the affect that rotor saliency has on the system. It was shown that the active rectification provided a higher efficiency than the passive rectification system, however the saliency of the rotor had little effect on the system
22

Video Deinterlacing using Control Grid Interpolation Frameworks

January 2012 (has links)
abstract: Video deinterlacing is a key technique in digital video processing, particularly with the widespread usage of LCD and plasma TVs. This thesis proposes a novel spatio-temporal, non-linear video deinterlacing technique that adaptively chooses between the results from one dimensional control grid interpolation (1DCGI), vertical temporal filter (VTF) and temporal line averaging (LA). The proposed method performs better than several popular benchmarking methods in terms of both visual quality and peak signal to noise ratio (PSNR). The algorithm performs better than existing approaches like edge-based line averaging (ELA) and spatio-temporal edge-based median filtering (STELA) on fine moving edges and semi-static regions of videos, which are recognized as particularly challenging deinterlacing cases. The proposed approach also performs better than the state-of-the-art content adaptive vertical temporal filtering (CAVTF) approach. Along with the main approach several spin-off approaches are also proposed each with its own characteristics. / Dissertation/Thesis / M.S. Electrical Engineering 2012
23

Tree-Based Deep Mixture of Experts with Applications to Visual Saliency Prediction and Quality Robust Visual Recognition

January 2018 (has links)
abstract: Mixture of experts is a machine learning ensemble approach that consists of individual models that are trained to be ``experts'' on subsets of the data, and a gating network that provides weights to output a combination of the expert predictions. Mixture of experts models do not currently see wide use due to difficulty in training diverse experts and high computational requirements. This work presents modifications of the mixture of experts formulation that use domain knowledge to improve training, and incorporate parameter sharing among experts to reduce computational requirements. First, this work presents an application of mixture of experts models for quality robust visual recognition. First it is shown that human subjects outperform deep neural networks on classification of distorted images, and then propose a model, MixQualNet, that is more robust to distortions. The proposed model consists of ``experts'' that are trained on a particular type of image distortion. The final output of the model is a weighted sum of the expert models, where the weights are determined by a separate gating network. The proposed model also incorporates weight sharing to reduce the number of parameters, as well as increase performance. Second, an application of mixture of experts to predict visual saliency is presented. A computational saliency model attempts to predict where humans will look in an image. In the proposed model, each expert network is trained to predict saliency for a set of closely related images. The final saliency map is computed as a weighted mixture of the expert networks' outputs, with weights determined by a separate gating network. The proposed model achieves better performance than several other visual saliency models and a baseline non-mixture model. Finally, this work introduces a saliency model that is a weighted mixture of models trained for different levels of saliency. Levels of saliency include high saliency, which corresponds to regions where almost all subjects look, and low saliency, which corresponds to regions where some, but not all subjects look. The weighted mixture shows improved performance compared with baseline models because of the diversity of the individual model predictions. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2018
24

Saliency Cut: an Automatic Approach for Video Object Segmentation Based on Saliency Energy Minimization

January 2013 (has links)
abstract: Video object segmentation (VOS) is an important task in computer vision with a lot of applications, e.g., video editing, object tracking, and object based encoding. Different from image object segmentation, video object segmentation must consider both spatial and temporal coherence for the object. Despite extensive previous work, the problem is still challenging. Usually, foreground object in the video draws more attention from humans, i.e. it is salient. In this thesis we tackle the problem from the aspect of saliency, where saliency means a certain subset of visual information selected by a visual system (human or machine). We present a novel unsupervised method for video object segmentation that considers both low level vision cues and high level motion cues. In our model, video object segmentation can be formulated as a unified energy minimization problem and solved in polynomial time by employing the min-cut algorithm. Specifically, our energy function comprises the unary term and pair-wise interaction energy term respectively, where unary term measures region saliency and interaction term smooths the mutual effects between object saliency and motion saliency. Object saliency is computed in spatial domain from each discrete frame using multi-scale context features, e.g., color histogram, gradient, and graph based manifold ranking. Meanwhile, motion saliency is calculated in temporal domain by extracting phase information of the video. In the experimental section of this thesis, our proposed method has been evaluated on several benchmark datasets. In MSRA 1000 dataset the result demonstrates that our spatial object saliency detection is superior to the state-of-art methods. Moreover, our temporal motion saliency detector can achieve better performance than existing motion detection approaches in UCF sports action analysis dataset and Weizmann dataset respectively. Finally, we show the attractive empirical result and quantitative evaluation of our approach on two benchmark video object segmentation datasets. / Dissertation/Thesis / M.S. Computer Science 2013
25

L’anaphore résomptive nominale : saillance et argumentation. Aspects contrastifs allemand - français / Nominal Anaphoric Encapsulation : Saliency and Argumentation. Contrastive Aspects German/French

Babillon, Laurence 25 November 2017 (has links)
Ce travail est consacré à l’étude contrastive du fonctionnement de l’anaphore résomptive à tête nominale (ARN) en allemand et en français. Il s’appuie principalement sur un corpus de textes journalistiques. Le journaliste est un scripteur qui, par le biais de son article, désire informer son lecteur, voire le faire adhérer à sa vision du monde. Mais il est soumis à des contraintes de place. L’ARN est un moyen linguistique de choix, car elle permet un compactage par abstraction et par généralisation des informations sous la forme d’un concept introduit par le nom-tête de l’ARN. Il en ressort que les constituants de l’ARN que sont le déterminatif, le nom-tête et son expansion, et l’ARN en soi jouent un rôle non négligeable au sein de l’énoncé et du paragraphe. Afin de rendre compte de la dimension cognitive du phénomène anaphorique, le recours à la notion de saillance permet de montrer le rôle central des ARN dans la cohérence textuelle. Ce type d’expressions anaphoriques joue en outre un rôle au niveau textuel et au niveau argumentatif. L’ARN est en effet une balise saillante au service de l’argumentation. Elle permet de structurer et d’organiser le discours, ainsi que de participer à la stratégie argumentative du journaliste. / The purpose of this work is to develop a contrastive study of nominal anaphoric encapsulation in German and in French. It is mainly based on a corpus of newspaper articles. Thanks to their articles, journalists want to inform their readers, and sometimes make them share their own world view. But journalists are forced to do with limited space. Nominal anaphoric encapsulation is a perfect linguistic tool because it allows concision through the abstraction and generalization of information – a concept being introduced by the head noun of the nominal anaphoric encapsulation. Therefore, constituent parts of nominal anaphoric encapsulation (determinative, head noun and its expansion) and nominal anaphoric encapsulation itself play an important role in the clause and in the paragraph. In order to analyse the cognitive dimension of the anaphoric phenomenon, we use the notion of saliency to show the central role of nominal anaphoric encapsulation in textual coherence. Furthermore, such anaphoric expressions play a role at the textual and argumentative levels. Nominal anaphoric encapsulation is actually a salient buoy supporting the argumentation. It serves to structure and organize the speech, and to participate in the argumentative strategy of journalists.
26

The Openness Buzz : A Study of Openness in Planning, Politics and Political Decision-Making in Sweden from an Institutional Perspective

Lundgren, Anna January 2017 (has links)
In today’s society of increased globalization and digitalization openness has become a buzzword. This raises questions about what we mean by openness and how it is interpreted in various contexts. This thesis has two aims; to explore how openness is interpreted in planning, politics and political decision-making, and to develop an analytical tool to assess openness in different contexts. A new institutional theory framework that centers on the interplay between institutions and actors has been used, and three empirical case studies in a Swedish context were conducted to analyze how openness is interpreted in planning in metropolitan regions, in politics through the political parties and in political decision-making in the Stockholm region. The research concludes that openness in planning, politics and political decision-making is interpreted along two inter-linked narrative lines: ’openness to people’ and ’openness to knowledge, information and ideas’. It was more common to talk about peoples’ accessibility to public services and participation in different parts of society (’openness to people’) than to talk about issues of transparency and ’openness to knowledge, information and ideas’. The institutional framework shows how openness is interpreted at different institutional levels. To what degree openness is expressed at different institutional levels vary by context. In planning for instance, openness is mainly interpreted in terms of governance, whereas in politics and political decision-making, openness is interpreted in an inter-play between culture and norms, institutions, governance and practice. The institutional framework complementary context-specific theories and elaborated into an analytical model, was found useful to explain what mechanisms are at play when dealing with openness in planning, politics and political decision-making, and can be applicable in future research of openness in other geographical or organizational contexts. / <p>QC 20170914</p>
27

Modeling Spatiotemporal Correlations between Video Saliency and Gaze Dynamics / 映像の視覚的顕著性と視線ダイナミクス間の時空間相関モデリング

Yonetani, Ryo 25 November 2013 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第17967号 / 情博第511号 / 新制||情||91(附属図書館) / 30797 / 京都大学大学院情報学研究科知能情報学専攻 / (主査)教授 松山 隆司, 教授 乾 敏郎, 教授 石井 信 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM
28

Identity, Wellness and Applied Pedagogy for the 21st Century Singer

Rohrer, Katherine L. January 2018 (has links)
No description available.
29

VISUAL SALIENCY ANALYSIS, PREDICTION, AND VISUALIZATION: A DEEP LEARNING PERSPECTIVE

Mahdi, Ali Majeed 01 August 2019 (has links) (PDF)
In the recent years, a huge success has been accomplished in prediction of human eye fixations. Several studies employed deep learning to achieve high accuracy of prediction of human eye fixations. These studies rely on pre-trained deep learning for object classification. They exploit deep learning either as a transfer-learning problem, or the weights of the pre-trained network as the initialization to learn a saliency model. The utilization of such pre-trained neural networks is due to the relatively small datasets of human fixations available to train a deep learning model. Another relatively less prioritized problem is amount of computation of such deep learning models requires expensive hardware. In this dissertation, two approaches are proposed to tackle abovementioned problems. The first approach, codenamed DeepFeat, incorporates the deep features of convolutional neural networks pre-trained for object and scene classifications. This approach is the first approach that uses deep features without further learning. Performance of the DeepFeat model is extensively evaluated over a variety of datasets using a variety of implementations. The second approach is a deep learning saliency model, codenamed ClassNet. Two main differences separate the ClassNet from other deep learning saliency models. The ClassNet model is the only deep learning saliency model that learns its weights from scratch. In addition, the ClassNet saliency model treats prediction of human fixation as a classification problem, while other deep learning saliency models treat the human fixation prediction as a regression problem or as a classification of a regression problem.
30

Essays in Transportation and Electoral Politics

Harmony, Xavier Joshua 01 March 2024 (has links)
Abstract 1 – The Importance of Transportation Policies in Local Elections Building and maintaining transportation systems is one of the most important functions of local government. It is a subject that concerns local residents, jurisdictions spend a lot of money on, and local politicians use to their political advantage. This study helps us understand how transportation issues feature in local elections. Through evaluating a dataset of 542 candidates from 219 local election races from 2022, this study explores which candidates for local office are more likely to have transportation policies, what kind of content is included in these policies, and what are the factors that make including different transportation content more or less likely. The analysis primarily uses website campaign content and a mix of qualitative and quantitative methods to answer these questions. I find a variety of factors affect the inclusion of transportation issues at the local level such as variations in governance, partisanship, and regional characteristics like a jurisdiction's size and transportation behavior. It was also evident that defining transportation issues was more common than proposing transportation policy solutions. Overall, this research provides more insight into how transportation policies are included in local elections. Abstract 2 – Saliency of Transportation Policies in State Legislative Elections: The Case of Virginia Transportation systems are expensive and directly impact important issues like climate change, equity, and quality of life. However, it is not clear how important transportation policies are in state-level elections. Using the Virginia 2021 state legislative election, this research uses candidate website data, Twitter data, and data about Virginia House of Delegates districts to answer three questions: which candidates are more likely to have transportation polices, what issues or transportation modes are included, and what factors make candidates more or less likely to focus on certain issues. Using descriptive statistics, and regression methods, this research found transportation issues varied by political party with top overall issues including transportation funding as well as expanding or improving transportation systems. Public transportation was the top non-car mode. Candidates were more likely to include transportation issues if district households had higher car ownership or a lower percentage of single occupancy vehicle commuters. Finally, differences in transportation issues could be partly explained by political party, incumbency, population density, and transportation habits. These results will be helpful for understanding how state government transportation agendas change, can better inform transportation advocacy efforts, and could help transportation professionals better understand the impact of their work. Abstract 3 – Does Voting Affect the Provision of Bus Service? Inequalities in the distribution of bus services are important to understand. This chapter adds to previous literature by exploring why inequalities exist. Specifically, does voting for elected officials affect inequalities in the delivery of bus services? This study explores this question using a quantitative approach as part of a quasi-experimental research design focusing on GoRaleigh in North Carolina and the Milwaukee County Transit System in Wisconsin. The analysis provides evidence of a relationship between voting behavior and bus service. This finding is observed across cities and elections with the relationships holding even when controlling for factors associated with a bureaucratic explanation for changing bus service, like changes to population or jobs. However, the strength of the relationship can change between elections, the type of elected official, and cities. Overall, this work provides more evidence of the politics behind transit service planning, especially the political influences of voting behavior in representative democracies. / Doctor of Philosophy / Abstract 1 – The Importance of Transportation Policies in Local Elections This study helps us understand how transportation issues feature in local elections. Specifically, this study explores which candidates for local office are more likely to have transportation policies, what kind of content is included in these policies, and what are the factors that make including different transportation content more or less likely. I find a variety of factors affect the inclusion of transportation issues at the local level such as variations in local control, partisanship, and regional characteristics like a jurisdiction's size and transportation behavior. Overall, this research provides more insight into how transportation policies are included in local elections. Abstract 2 – Saliency of Transportation Policies in State Legislative Elections: The Case of Virginia While transportation systems affect many important issues, it is not clear how important transportation policies are in state-level elections. Using 2021 Virginia state elections, this research answers three questions: which candidates are more likely to have transportation polices, what issues or transportation modes are included, and what factors make candidates more or less likely to focus on certain issues. This study found top issues included transportation funding as well as expanding or improving transportation systems while public transportation was found to be the top non-car mode. Candidates were more likely to have transportation policies if their districts had higher car ownership rates or a lower percentage of people commuting using a car. Finally, differences in transportation issues could be partly explained by political party, incumbency, population density, and transportation habits. These results could be helpful for understanding state government transportation agendas, can better inform transportation advocacy efforts, and could help transportation professionals better understand the impact of their work. Abstract 3 – Does Voting Affect the Provision of Bus Service? Does voting for elected officials affect the delivery of bus services? This study explores this question by focusing on two transit systems: GoRaleigh in North Carolina and the Milwaukee County Transit System in Wisconsin. The study demonstrates voting behavior has a relationship to changes in bus service. This finding is seen in both cities and multiple elections with the impacts still observable even when considering other factors like changes to population or jobs. However, the size of the voting impact can be different between elections, the type of elected official, and cities. Overall, this work provides more evidence of the politics behind transit service planning.

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