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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.
1

Police Legitimacy Across High-Crime Contexts: An Examination of Neighborhood-Level Expressive Concerns and Accumulated Experiences

Spencer, Tyrell 01 December 2018 (has links)
Research on public perceptions of the police has identified various individual characteristics that have been found to influence police legitimacy. These individual characteristics often reflect demographic factors such as race/ethnicity, age and socioeconomic status. In addition to demographic factors, process-based factors such as procedural justice and fairness have also been found to influence individual perceptions of legitimacy. What has not been fully established within the literature on public perceptions of police is the extent to which neighborhood characteristics and context shape neighborhood assessments of police legitimacy. This thesis seeks to fill in the gap on public perceptions of police by examining whether expressive concerns and accumulated experiences with police at the neighborhood-level influence legitimacy judgments across high-crime areas. Using baseline survey data collected for the St. Louis County Hot Spots in Residential Areas (SCHIRA) project between March and May of 2012, residents in St. Louis County, Missouri are aggregated to 71 crime hot spots. Findings suggest that neighborhood-level expressive concerns and accumulated experiences do not influence legitimacy judgments across the high-crime areas. However, low neighborhood cohesion predicts the percentage of residents in the area having a recent negative experience with police. Implications for future research and police practice are discussed.
2

Akumulační řetězový dopavník / Accumulated chain conveyor

Tlapák, Tomáš January 2008 (has links)
This diploma work deals with a design of the accumulated chain conveyor with circuit palette. The work is concentrated on the design of workings and functional and strenght caltulations. The drawing dokumentacions are within the range detail drawings and assembly drawings.
3

Investment Strategies : Can accumulated stock recommendations provide positive abnormal return?

Sand, Adam, Svahn, Emil, Nilsson Lange, Kim January 2009 (has links)
Abstract   Purpose The purpose of this thesis is; “To find out whether a strategy based on accumulated stock recommendations are able to outperform mutual funds and/or index funds with similar holdings over time”. Background During the past 30 years the interest for the financial market has been ever increasing. With the increased interest for the financial market, also an increased interest for the different investment alternatives have developed, thus also the amount of various financial products. Further there has been a discussion whether the different investment products actually add value to the investors. Method To be able to reach our purpose we have constructed a portfolio containing stocks based on recommendations. We have also come up with a method in order to decide the weights of the individual stocks in our portfolio. Further, we have used existing theories in order to estimate the return and the standard deviation. We have also benchmarked our portfolio against popular funds on the market. Conclusion We have seen that our portfolio during the six years running have performed better than the existing funds and also resulted in a lower standard deviation i.e. risk. Thus the results are applicable on our specific data, more research is needed in order to make any statements of statistical significance.
4

Visualization of neural data : Dynamic representation and analysis of accumulated experimental data

Henning, Gustav January 2015 (has links)
The scientific method is an integral part of the investigation and exploration of hypotheses. Although procedures may vary from one field to the next, most have common identifiable stages. Today, there is no lack of tools that illustrate data in different graphical mediums. This thesis focuses instead on the type of tools that researchers use to investigate their hypotheses’ validity.When a sufficient amount of data is gathered, it can be presented for analysis in meaningful ways to illustrate patterns or abnormalities that would otherwise go unnoticed when only viewed in raw numbers. However useful static visualization of data can be when presented in ascientific paper, researchers are often overwhelmed by the number of plots and graphs that can be made using only a sliver of data. Therefore, this thesis will introduce software which purpose is to demonstrate the needs of researchers inanalyzing data from repeated experiments in order to speed up the process of recognizing variations between them. / Den vetenskapliga metoden är en integral del av undersökningen och utforskandet av hypoteser. Medan procedurer varierar mellan fält liknar de varandra i stora drag. Idag finns det ingen brist på verktyg som visualiserar data i olika grafiska kontexter. Istället fokuserar denna tes på de typ av verktyg som forskare använder för att undersöka integriteten av hypoteser.           När tillräckligt med data samlats finns det olika sätt att presentera denna på ett meningsfullt sätt för att demonstrera mönster och avvikelser som skulle förbli osedda i endast siffror.             Hurvida användbar statisk visualisering av data är som grafik till vetenskapliga rapporter gäller nödvändigtvis inte samma sak vid analys på grund av de många kombinationer av visualisering som ofta finns. Mjukvara kommer att introduceras för att demonstrera behovet av dynamisk representation vid analys av ackumulerad data för att påskynda upptäckten av mönster och avvikelser.
5

Accumulated Surfaces & Least-Cost Paths: GIS Modeling for Autonomous Ground Vehicle (AGV) Navigation

Stahl, Christopher Wayne 21 June 2005 (has links)
The Geographic Information System (GIS) is a crucial part of any land navigation system. Autonomous ground vehicles should have access to stored geographic data and the ability to manipulate it for routing purposes. Since there is no human interaction involved in operating these vehicles, data that a human driver would use to make decisions must be stored in the GIS. The data which represent the earth's surface become a series of factors and constraints which translate to friction in terms of mobility. Factors need to be weighted appropriately, but require a sensitivity analysis before designating these weights. Constraints do not require any weight because they represent absolute barriers which cannot be traveled upon. All GIS layers are incorporated into the raster environment, so that an accumulated surfaces can be built on which a least-cost path can be located. The sensitivity analysis allows generation of many routes which can be field tested for the appropriate weight selection for each factor. Ultimately, the entire process would select an optimal path and output closely spaced waypoints which the vehicle can follow. / Master of Science
6

Identification of barriers and least cost paths for autonomous vehicle navigation using airborne LIDAR data

Poudel, Om Prakash 21 August 2007 (has links)
In the past several years, the Defense Advanced Research Projects Agency (DARPA) has sponsored two Grand Challenges, races among autonomous ground vehicles in rural environments. These vehicles must follow a course delineated by Global Positioning System waypoints using no human guidance. Airborne LIDAR data and GIS can play a significant role in identifying barriers and least cost paths for such vehicles. Least cost paths minimize the sum of impedance across a surface. Impedance can be measured by steepness of slope, impenetrable barriers such as vegetation and buildings, fence lines and streams, or other factors deemed important to the vehicle's success at navigating the terrain. This research aims to provide accurate least cost paths for those vehicles using airborne LIDAR data. The concepts of barrier identification and least cost path generation are reviewed and forty-five least cost paths created with their performance compared to corresponding Euclidean paths. The least cost paths were found superior to the corresponding Euclidean paths in terms of impedance as they avoid barriers, follow roads and pass across relatively gentler slopes. / Master of Science
7

Essays on Other Comprehensive Income

Black, Dirk January 2014 (has links)
<p>In Chapter 1, I review the existing literature on the investor and contracting usefulness of other comprehensive income (OCI) components. In Chapter 2, I perform empirical tests focused on one aspect of investor usefulness of accounting information: risk-relevance. I examine whether OCI component volatilities are associated with investors' returns volatility using a sample of bank holding companies from 1998 to 2012. The results indicate that the volatilities of unrealized gains and losses on available-for-sale (AFS) securities and cash-flow hedges, typically deemed beyond managers' control, are negatively associated with risk, while volatilities of OTTI losses, over which managers have relatively more control, are positively associated with risk. The results are consistent with investors perceiving the volatility of non-OTTI AFS unrealized gains and losses as relatively less important, less risky, or less risk-relevant, than the volatility of OTTI losses, and perceiving the volatility of OTTI losses as an informative signal about risk. In Chapter 3, I find that Tier 1 Capital including more components of accumulated other comprehensive income (AOCI), as stipulated by Basel III, is no more volatile than pre-Basel-III Tier 1 Capital, and that the volatilities of the AOCI components new to Tier 1 Capital are not positively associated with risk. In Chapter 4, I discuss future research.</p> / Dissertation
8

Efeitos da radiação em transistores túnel-FET de porta tripla. / Radiation effects on triple-gate tunnel-FET transistors.

Torres, Henrique Lanza Faria 28 May 2018 (has links)
Frente à crescente necessidade de que novas tecnologias sejam capazes de operar com confiabilidade em ambientes hostis, a análise dos efeitos da radiação ionizante em dispositivos semicondutores se tornou um ramo de pesquisa em contínua ascensão, contribuindo para o desenvolvimento de tecnologias estratégicas e promovendo o aprimoramento científico e o desenvolvimento tecnológico da humanidade. Por outro lado, a atual tecnologia CMOS de fabricação de circuitos integrados apresenta sinais de limitação, em grande parte, devido às características físicas inerentes ao seu princípio de funcionamento, sendo necessário, portanto, que dispositivos com novos mecanismos de operação e geometrias sejam desenvolvidos. Dentre eles, transistores de tunelamento induzido por efeito de campo (TFET) se destacam por apresentarem menor corrente de dreno quando desligados e a possibilidade de se atingir inclinações de sublimiar abaixo do limite teórico estabelecido por dispositivos MOSFET de 60 mV/déc à temperatura ambiente, permitindo-se a redução da tensão de alimentação dos transistores para cerca de 0,5 V. Buscando contribuir com as necessidades destas duas áreas de pesquisa, neste projeto de mestrado, foi analisado o comportamento de TFETs de silício com porta tripla, fabricados sobre lâmina SOI (silício sobre isolante), submetidos a até 10 Mrad(Si) de dose acumulada total enquanto não polarizados, gerada por uma fonte de prótons de 600 keV de energia. Em uma análise inicial, após exposição de dispositivos de 1 µm de largura de aleta a uma dose de 1 Mrad(Si), foi possível observar uma redução no nível corrente de dreno de estado ligado do dispositivo (ION ? 300 pA) de até 10%, não associada à uma alteração da corrente de porta. Além disso, o efeito da radiação nesses transistores reduz de 10% para 2% quando se aumenta o comprimento do canal de 150 nm para 1 µm. As razões para ambos os fenômenos foram discutidas com base na competição entre os efeitos de divisão da corrente de dreno na primeira e segunda interfaces e do aumento da resistência de canal em dispositivos mais longos. Para uma análise em função da dose acumulada total, dispositivos SOI TFET e SOI MOSFET, ambos de porta tripla, foram caracterizados eletricamente 14 dias após cada etapa de irradiação. De maneira geral, dispositivos de ambas as tecnologias, com largura de aleta igual a 40 nm, apresentaram baixa susceptibilidade aos efeitos cumulativos da radiação ionizante. No entanto, quando considerados dispositivos com largura de aleta muito maior que a altura da aleta (WFIN = 1 µm), nos quais a influência das portas laterais sobre o acoplamento eletrostático do canal é praticamente inexistente, transistores túnel-FET se destacaram positivamente. Esses dispositivos se mostraram resistentes aos efeitos de dose ionizante total (TID) mesmo para doses de 5 Mrad(Si), enquanto os transistores SOI MOSFET apresentaram uma variação gradual de seus parâmetros a cada dose acumulada. Um exemplo disso é a variação observada na inclinação de sublimiar, de 32,5% nos transistores SOI MOSFET e 5,6% nos transistores SOI TFET. Somente após 10 Mrad(Si) de irradiação por prótons é que os TFETs de aleta larga apresentaram variações mais significativas em sua curva de transferência (ID x VG). Tanto para a configuração como tipo P quanto para a configuração como tipo N, notou-se um deslocamento de até 80 mV da curva de transferência do dispositivo para a esquerda, provocado, segundo análise via simulações, pelas cargas fixas positivas geradas pela irradiação no óxido enterrado do dispositivo. Adicionalmente, foi possível observar um aumento da corrente de tunelamento assistido por armadilhas (TAT) nesses dispositivos, provocada pelo aumento da densidade de estados de interface causada também pelos efeitos de TID. O aumento de TAT foi reconhecido como o principal responsável pela degradação de 23,3% da inclinação de sublimiar dos TFETs, com WFIN igual 1 µm, após 10 Mrad(Si). Apesar das mudanças observadas, foi possível se sugerir, através da comparação com transistores SOI MOSFET de dimensões equivalentes, que transistores de tunelamento induzido por efeito de campo podem, futuramente, se tornar referência no quesito imunidade aos efeitos de dose ionizante total. / In light of the increasing need for new technologies to be able to operate reliably in harsh environments, the analysis of the effects of ionizing radiation on semiconductor devices has become a continually rising field of research, contributing to the development of strategic technologies and promoting scientific improvement and technological development of humankind. On the other hand, the current CMOS technology for the manufacture of integrated circuits shows signs of limitation, mostly, due to the physical characteristics inherent to its operating principle, thus, it is necessary that devices with new operating mechanisms and geometries be developed. Among them, tunnel field-effect transistors (TFET) stand out because of its lower OFF state current and the possibility of reaching subthreshold swing below the theoretical limit established by MOSFET devices of 60 mV/dec at room temperature, allowing to reduce transistors supply voltage to about 0.5 V. In order to contribute with both areas, the behavior of silicon based triple gate TFETs fabricated on a SOI (silicon-on-insulator) substrate and exposed to a total cumulative dose of 10 Mrad (Si) (while not biased) generated by a 600 keV proton beam was analyzed. In an initial analysis after exposure of 1 µm width devices to 1 Mrad(Si), it was possible to observe an ON state current reduction (ION ? 300 pA) up to 10%, not associated to a gate current change. Beyond that, irradiation effects on these devices reduce from 10% to 2% with the channel length increasing from 150 nm to 1 µm. The reasons behind these phenomena were discussed based on the competition between a high channel resistance present in longer devices and the TFET drain current reduction due to the irradiation. For a total cumulative dose analysis, triple gate SOI TFET and triple gate SOI MOSFET devices were characterized 14 days after each irradiation phase. In general, devices of both technologies, with 40 nm fin width, presented low susceptibility to the cumulative effects of ionizing radiation. However, for devices with fin width larger than fin height (WFIN = 1 µm) in which the influence of side gates on the electrostatic coupling of the channel is weak, tunnel-FET transistors have stood out. These devices were resistant to the effects of total ionizing dose (TID) even for doses as high as 5 Mrad(Si), while SOI MOSFET transistors showed a gradual variation of their parameters at each accumulated dose. The variation observed for the subthreshold swing, for example, was about 32.5% for SOI MOSFET devices and 5.6% for SOI TFET devices. TFETs with wider fin have shown significant variations on its transfer characteristic (ID x VG) only after 10 Mrad(Si) of proton irradiation. For both P-type and N-type configurations, it was observed a shift of the transfer curve to the left up to 80 mV caused by, according to simulations, the positive fixed charges generated in the buried oxide by irradiation. In addition, it was possible to observe a trap assisted tunneling (TAT) current increase caused by interface states promoted by TID effects. The increase of TAT was recognized as the main responsible for the degradation of 23.3% of the subthreshold swing of the TFETs after 10 Mrad(Si). In spite of the observed changes, it was possible to suggest, through comparison with SOI MOSFET devices of equivalent dimensions, which tunnel field-effect transistors may become a reference when considering immunity against total ionizing dose effects.
9

Estudo do efeito de pausas introduzidas em testes de fadiga de amplitude variável. / Study of the effect of introduced pauses in fatigue tests under variable amplitude.

Angelo, Clayton Mamedes 28 January 2016 (has links)
É muito importante para a indústria fornecer produtos competitivos e que exerçam corretamente as suas funções perante o cliente. Uma das ferramentas existentes para atingir estes objetivos é a realização de testes de fadiga e durabilidade cada vez mais refinados e em espaço mais curto de tempo. Uma das maneiras de se executar testes de fadiga mais precisos é utilizando parâmetros que sejam fiéis à solicitação que o produto sofre durante o seu uso. Com esse intuito surgiram os testes de fadiga sob amplitude variável. Juntamente com eles surgem as particularidades deste tipo de solicitação, que é de natureza complexa. Algumas particularidades são a dependência do resultado na história de carregamento (também chamada de \"interação de cargas\") e a variação abrupta do nível de carga durante o tempo de aplicação. Fenômenos estes chamados de sobrecarga ou subcarga (overload e underload), que aqui serão agrupados, muitas vezes de forma simplista, de perturbações no espectro de fadiga. A finalidade principal deste trabalho é descrever a influência das perturbações ocorridas nas solicitações nos testes de fadiga em regime de amplitude variável, mais precisamente em testes de bancada, em que se busca a reprodução de situações de trabalho reais de um componente. Apesar de esse assunto ser alvo de diversas investigações recentes, nenhum trabalho tem como foco a influência das paradas (completa remoção de carga) realizadas durante um teste de fadiga acelerado. Essas paradas são extremamente comuns na prática laboratorial, seja por manutenção do equipamento, inspeção da amostra ou necessidade de operação. O objeto alvo de estudo nesta pesquisa é um suporte metálico de buzina, utilizado em automóveis de passeio. Apesar de sua concepção simples, tal componente é responsável por exercer funções importantes e é sujeito a uma interessante gama de solicitações. Como resultado observou-se que a aplicação das paradas durante os testes de fadiga simulados no componente automotivo, provoca variações em sua vida útil total. E o tempo de parada também exerce influência nesta variação observada. Essas paradas não se encaixam perfeitamente nas classificações de perturbações no espectro registradas na literatura. Por esse motivo o trabalho se propõe ainda a sintetizar e uniformizar a terminologia para as variações abruptas de tensão aplicadas no tempo (as sobrecargas e as subcargas), tendo em vista que ocorre a falta de consenso entre os termos utilizados atualmente na literatura e seus respectivos conceitos. / It is very important to the industry to deliver competitive products that can properly perform their functions to the final customer. One existing tool for achieve this objective is the usage of abbreviated durability and fatigue tests. For more precise tests, the required parameters must be reliable when compared to the efforts that the component is submitted at the field during your real performance. In order to achieve these results, the fatigue tests under variable amplitude loading came to existence. Together came also in existence the singularities from this complex behavior. Some of these singularities are the dependence in loading history (also called \"load interaction effects\") and the abrupt load variation level during the test time. These phenomenons are called overloads or underloads. These particularities will be grouped in this work as \"perturbations\" on the fatigue spectrum. The main objective of this work is to describe the influence of these perturbations upon the fatigue tests under variable amplitude loading, more precisely on bench tests, where one seeks the concise reproduction of the real work situations for one component or system. Although this subject lately has caused more interest to the researchers, no work which focuses on the influence of the \"pauses\" (complete absence of load during the test) upon accelerated fatigue tests has been published yet until this moment. These pauses are extremely common due to equipment maintenance, test sample inspections or operational routines. The target of this work is a metallic horn bracket, which is used in light passenger vehicles. Although this is a simple component, it has important functions to perform and is subjected to a wide range of loads types. As result, there was been verified that the presence of the \"pause\" during the simulated fatigue tests causes changes in their total useful life. And the magnitude of the pause has your role too. Moreover, the pause do not properly fits into the current classifications for the perturbations on the fatigue specter that are today available on the literature. For theses reason, this work tries to resume and unify the terminology of the abrupt load variations during time (overloads and underloads) because there is some lack of consensus between the actual terminology and their concepts.
10

Nova abordagem para a interpretação da Reserva Legal com auxílio da geoestatística. / New approach to the interpretation of the Legal Reserve with the aid of geostatistics.

Okumura, Miriam Harumi 17 February 2014 (has links)
A Floresta Amazônica é palco de um grande número de atividades de desflorestamento, como a mineração artesanal, agropecuária e comércio de madeira. A fim de se ter uma diminuição dos impactos ambientais, os órgãos fiscalizadores têm tentado regular estas atividades e orientá-las para métodos de operação mais responsável. Este trabalho descreve a iniciativa por meio do monitoramento dessas áreas de floresta localizadas perto dessas regiões de desmatamento, porque os elementos fundamentais, tais como a biomassa e acúmulo de carbono das árvores podem ser adequadamente monitorados contra distúrbios ocasionais trazidos por essas atividades. A atual abordagem padrão na Amazônia é monitorar todas as árvores da floresta dentro de uma área chamada de transecto, também designado como inventário florestal, mantendo um registro rigoroso de seu comportamento e crescimento. No entanto, essas atividades são restritas às áreas de controle que estão localizados em regiões estratégicas e não representam toda a área a ser monitorada. Esta pesquisa explora uma nova metodologia baseada na geoestatística e destinada a otimização da amostragem, estendendo-se para o estudo de áreas florestais muito maiores, mantendo a utilização dos recursos humanos unitária inalterada, e, ao mesmo tempo, aumentar a superfície das áreas de estudo e a manter a confiança nos resultados. A metodologia proposta permite a seleção da Reserva Legal - RL, a ser feita de acordo com a distribuição real de acumulação de carbono da floresta, em vez de confiar na utilização de área percentual proposta por lei e no senso comum de proprietários / órgãos fiscalizadores. Esta metodologia foi aplicada na Floresta Nacional de Tapajós (FLONA Tapajós), no Estado do Pará, Brasil, utilizou-se de conjunto de dados disponíveis, para otimizar as amostras e monitorar a capacidade da floresta de armazenar carbono. A presente metodologia pretende contribuir para uma diminuição do custo das atividades de monitoramento por unidade de área, aumento da precisão para localização RL, e simplificação dos procedimentos através da aplicação de um conjunto de ferramentas de fácil utilização. Os resultados mostraram que a aplicação de estudos geoestatísticos para determinação de RL é um procedimento viável, pois a estrutura do variograma se mantém mesmo com a amostragem sofrendo uma diminuição randômica de até 50% da área de cobertura vegetal, conseguindo manter o mesmo resultado da amostragem na totalidade da cobertura vegetal. / The Amazon Rainforest is the scene of a large number of deforestation activities such as artisanal mining, agriculture and timber trade. For the purpose of have reduced environmental impacts, regulatory agencies have attempted to regulate these activities and direct them towards more responsible methods of operation. This paper describes the initiative by monitoring these forest areas located near these regions of deforestation, because the core elements, such as biomass and carbon accumulation of the trees can be adequately monitored against occasional disturbances brought by these activities. The current standard approach in the Amazon is to monitor all the trees of the forest within an area called the transect, also designated as forest inventory, keeping a strict record of their behavior and growth. However, these activities are restricted to control areas that are located in strategic regions and do not represent the whole area to be monitored. This research explores a new methodology based on geostatistics and designed to optimize the sampling, extending the study of much larger forest areas, keeping unchanged the use of human resources unit, and at the same time increase the surface areas of study and to maintain confidence in the results. The proposed methodology allows the selection of the Legal Reserve - RL, to be made according to the actual distribution of carbon accumulation in the forest, instead relying in using area percentage proposed by law and common sense of proprietary / regulatory agencies. This methodology was applied in the Tapajós National Forest (FLONA Tapajós), State of Pará, Brazil, we used the data set available, to optimize the sample and monitor the forest\'s ability to store carbon. This methodology intends to contribute to reducing the cost of monitoring activities per unit area, increased precision for location RL, and simplifying procedures by applying a set of easy to use tools. The results showed that application of geostatistical studies for determination of RL is a viable procedure, because the structure of the variogram is maintained even with a random sampling suffering decreased to 50% of the area of vegetation, even managing to keep the sampling result the total vegetation cover.

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