Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 88-93). Also available via the Internet.

Metal-semiconductor contacts are of fundamental importance to the operation of all semiconductor devices. There are many competing theories of Schottky barrier formation but as yet no quantitative predictive model exists to adequately explain metal-semiconductor interfaces. The II-VI compound semiconductors CdTe, CdS and ZnSe have recently come to the fore with the advent of high efficiency photovoltaic cells and short wavelength light emitters. Major problems still exist however in forming metal contacts to these materials with the desired properties. This work presents results which make a significant contribution to the theory of metal/II-VI interface behaviour in terms of Schottky barriers to n-type CdTe, CdS and ZnSe. Predominantly aqueous based wet chemical etchants were applied to the surfaces of CdTe, CdS and ZnSe which were subsequently characterised by X-ray photoelectron spectroscopy. The ionic nature of these II-VI compounds meant that they behaved as insoluble salts of strong bases and weak acids. Acid etchants induced a stoichiometric excess of semiconductor anion at the surface which appeared to be predominantly in the elemental or hydrogenated state. Alkaline etchants conversely induced a stoichiometric excess of semiconductor cation at the surface which appeared to be in an oxidised state. Metal contacts were vacuum-evaporated onto these etched surfaces and characterised by current-voltage and capacitance-voltage techniques. The surface preparation was found to have a clear influence upon the electrical properties of Schottky barriers formed to etched surfaces. Reducing the native surface oxide produced near ideal Schottky diodes. An extended study of Au, Ag and Sb contacts to [mathematical formula] substrates again revealed the formation of several discrete Schottky barriers largely independent of the metal used; for [mathematical formula]. Deep levels measured within this study and those reported in the literature led to the conclusion that Fermi level pinning by native defects is a dominant mechanism in Schottky barrier formation in these systems.

Brain-Computer-Interfaces (BCIs) provide a novel way of communication by interpreting different types of brain states. This principle of reading minds makes BCIs a challenging but at the same time fascinating topic among the different disciplines of electrophysiology and biomedical-signal-processing. This work describes the development of a non-invasive BCI approach using steadystate- visual-evoked-potentials (SSVEP) as a mental strategy. SSVEP based BCIs require an external visual stimulation, which in this work is transmitted by a LCD-screen. Consequently, a visual reactive BCI is integrated as a plug-in into the open source project MNE-CPP, which provides an extensive library for brain monitoring and processing. MNE-Scan, as a standalone software from MNE-CPP, contains the necessary real-time source localization and is used as a framework for the BCI. Moreover, an expansion with a screen keyboard device shows the BCI’s practicability. The work’s result delivers a functioning SSVEP BCI approach with an average detection accuracy of 86 %. However, it is shown, that a transition from a BCI on sensor level to a BCI on source level is challenging and requires a certain pre-development, whereby a first approach of the BCI only was realized on sensor level in this work. / Tesis

Submitted by Luiza Kleinubing (luiza.kleinubing@udesc.br) on 2018-03-07T19:35:35Z No. of bitstreams: 1 PATRICIA T. PARRELA.pdf: 2224183 bytes, checksum: 4973c55995383dacf92f91fa726683da (MD5) / Made available in DSpace on 2018-03-07T19:35:35Z (GMT). No. of bitstreams: 1 PATRICIA T. PARRELA.pdf: 2224183 bytes, checksum: 4973c55995383dacf92f91fa726683da (MD5) Previous issue date: 2016-07-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work is part of a larger research that in its first stage developed an evaluation project of the MD3E (Method of Deployment in Stages [Santos, 2005]) digital interface based on usability principles (Gobbi, 2015). The result was an early version of the interface developed in conjunction with experts in Design and Usability. This study aims, in this second step, advance the development and implementation of this interface and test its usability on the end user. After an exploratory study on subjects pertaining to usability and HCI (Human Computer Interaction) along with the return of the experts who participated in the previous stage, it was developed and implemented in web programming language (HTML, CSS and Javascript) an improved version of that interface. In order to simulate its everyday use and test the practical actions most commonly performed by the users, the interface was tested with 20 subjects: 15 Design students and 5 Design teachers. The following metrics - based on ISO 9241-11 - were measured by the tests: efficiency (measured by errors during the performancing of the tasks), efficiency (measured by the task completion time) and satisfaction (measured by responses to questionnaires). The test results were compared with the results of the specialists to verify if the improvements applied reflected on the results. It was observed that the metrics of efficiency and satisfaction showed improvements in the results, and the efficiency differences were even statistically significant. The results of all metrics were then analyzed in detail to deepen the understanding of the interaction with the interface, the possible reason of the results and to suggest further improvements. It was concluded that this research was important to identify the elements with good usability and to aim more accurately the potential problems to be addressed in the following developments of this interface. The ultimate goal is to eventually provide a comprehensive tool for Design teaching. / Este trabalho faz parte de uma pesquisa maior que na sua primeira etapa desenvolveu um projeto de avaliação da interface digital do MD3E (Método de Desdobramento em 3 Etapas [Santos, 2005]) baseada em princípios de usabilidade (GOBBI, 2015). O resultado foi uma interface em versão inicial desenvolvida em conjunto com especialistas em Design e Usabilidade. O presente trabalho busca, em esta segunda etapa, avançar o desenvolvimento e a implementação desta interface e testar sua usabilidade junto ao usuário final. Após um estudo exploratório sobre assuntos pertinentes à Usabilidade e IHC (Interação Humano-Computador) juntamente com o retorno dos especialistas participantes da etapa anterior, foi desenvolvida e implementada em linguagem de programação web (HTML, CSS e Javascript) uma versão aprimorada daquela interface. Com o objetivo de simular seu uso cotidiano e testar as ações práticas mais comumente realizadas pelos usuários, a interface foi testada junto a 20 sujeitos: 15 alunos e 5 professores de Design. As seguintes métricas - baseadas na ISO 9241-11 - foram medidas nos testes: eficiência (medida pelos erros cometidos durante a realização das tarefas), eficácia (medida pelo tempo de realização das tarefas) e satisfação (medida por respostas a questionários). Os resultados dos testes foram comparados com os resultados dos testes dos especialistas para verificar se as melhorias aplicadas refletiam nestes resultados. Foi observado que as métricas de Eficiência e Satisfação obtiveram melhorias nos resultados, sendo que na Eficácia as diferenças foram estatisticamente significativas. Os resultados de todas as métricas foram, então, analisados detalhadamente para aprofundar a compreensão da interação com a interface, o possível motivo dos resultados e sugerir novas melhorias. Concluiu-se que esta pesquisa foi importante para identificação dos elementos com boa usabilidade e para apontar com mais exatidão os potenciais problemas e serem abordados no decorrente desenvolvimento da interface. O objetivo final é proporcionar futuramente uma ferramenta completa para ensino de Design.

Thesis (Masters Diploma (Technology))--Cape Technikon, Cape Town,1984 / The excessive usage of peripheral devices such as TTY's, VDU's and printers, have a significant load on the frontend processor of the Alcatel X83 minicomputer. Because of this, the response time of the front-end processor to the peripher~ls is excessive. This can also be attributed to the fact that the peripherals have small buffers or no buffers at all. These peripheral devices also operate at slow speeds. A slow response time from the mini-computer results in decreased productivity. The mini-computer does not provide ports for parallel printers even though there is an abundance of these type of printers. The unavailability of a variety of interfaces on the minicomputer makes the reconfiguration of the peripheral network inflexible. Replacing the existing peripheral equipment in order to overcome the above limitations will be costly. This thesis describes the design, development and implementation of a data buffer and interface converter which would overcome the above mentioned limitations.

Dissertação (mestrado)—Universidade de Brasília, Instituto de Psicologia, 2010. / Submitted by Jaqueline Ferreira de Souza (jaquefs.braz@gmail.com) on 2011-09-09T12:06:21Z No. of bitstreams: 1 2010_TarcisioRibeiroFreireJr.pdf: 1653040 bytes, checksum: 46ea89e17f856da11681a6878fcd45ac (MD5) / Approved for entry into archive by Jaqueline Ferreira de Souza(jaquefs.braz@gmail.com) on 2011-09-09T12:06:35Z (GMT) No. of bitstreams: 1 2010_TarcisioRibeiroFreireJr.pdf: 1653040 bytes, checksum: 46ea89e17f856da11681a6878fcd45ac (MD5) / Made available in DSpace on 2011-09-09T12:06:35Z (GMT). No. of bitstreams: 1 2010_TarcisioRibeiroFreireJr.pdf: 1653040 bytes, checksum: 46ea89e17f856da11681a6878fcd45ac (MD5) / A inserção de sistemas informatizados no ambiente de trabalho proporciona uma série de facilidades e comodidades para os seus usuários, como também é responsável por novos e diferentes tipos de dificuldades. Nessa pesquisa busca-se verificar se o software CADI-JUS atende as necessidades das atividades de cadastramento/consulta de informações referentes aos imóveis e terrenos da Justiça Federal. Com base em pressupostos metodológicos da Ergonomia, o método do estudo acompanha os princípios que subsidiam a formulação da Análise Ergonômica do Trabalho - AET enriquecida por procedimentos formulados por Silvino (2004) denominado de Tecnologia de Avaliação e (Re)Concepção de Interfaces – TAI. O estudo divide-se em duas etapas. A primeira, Planejamento, corresponde à (a) análise documental; (b) entrevistas semi-estruturadas; e (c) reuniões realizadas com responsáveis pela instituição e pelo controle do aplicativo. A segunda, Análise do Aplicativo, pauta-se na realização de (d) análises intrínseca e (e) extrínseca do aplicativo. Portanto, busca-se avaliar por meio destas abordagens os fatores que condicionam o uso do software, de modo que ao término da pesquisa seja produzido um relatório diagnóstico destes fatores e, atrelado a estes, recomendações que favoreçam as necessidades de uso do aplicativo em situação de trabalho. Os resultados encontrados reafirmam que o modo pelo qual os novos sistemas informatizados são desenvolvidos favorece o surgimento de ferramentas focadas em tecnologias e que na maioria dos casos ignoram os critérios básicos de usabilidade. ___________________________________________________________________________________ ABSTRACT / The introduction of computerized systems in the workplace provides a range of facilities and amenities for its users, but also is responsible for new and different kinds of difficulties. In this research seeks to verify the software CADI-JUS support the needs of the activities of registration / consultation of information relating to building and land of the Justiça Federal. Based on methodological assumptions of ergonomics, the method of study follows the principles that underlie the formulation of Ergonomic Analysis of Work - AET enriched with procedures formulated by Silvino (2004) called the Tecnologia de Avaliação e (Re)Concepção de Interfaces - TAI. The study is divided into two stages. The first, Planning, represents the completion of (a) document analysis, (b) semi-structured interviews, and (c) meetings with authorities of the institution and the control of the application. The second, analysis of the application, staff on the achievement of (d) an intrinsic analysis, and (e) extrinsic analysis of application. Therefore, we assessed by means of these approaches the factors that influence the use of the software, so that the end of the research is produced a report and diagnosis of these factors, coupled with these recommendations that support the needs of application usage in a situation work. The results reaffirm that the way the new IT systems are developed favors the emergence of tools focused on technology and that in most cases ignore the basic criteria of usability.

Orientador: Adriane Maria Brito R. de Carvalho / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-07-22T21:19:03Z (GMT). No. of bitstreams: 1 Lima_SergioMuinhosBarroso_M.pdf: 2073959 bytes, checksum: 569cb45e9ea6c4ef831d95ad96d1eb14 (MD5) Previous issue date: 1997 / Resumo: Nesta dissertação é apresentada a implementação de um tradutor de linguagem Natural (LN) para a linguagem LEGAL, que é uma extensão da linguagem SQL que inclui operadores espaciais e facilidades para a manipulação de campos e objetos geográficos. O objetivo deste trabalho é auxiliar os usuários de um Sistema de Informação Geográfica, não especialistas em computação, na formulação de consultas através da utilização de LN. As vantagens e desvantagens da interação em LN são apresentadas, bem como a funcionalidade de cada módulo constituinte do tradutor: além disso, os problemas lingüísticos e as particularidades que as consultas espaciais possuem e que foram tratadas pelo tradutor são apresentadas. / Abstract: This dissertation presents the implementation of a Translator from Natural Language to LEGAL, which is an extension of the SQL language and which includes spatial operators to manipulate geo-fields and geo-objects. The goal of this dissertation is to help Geographical Information System users, who are not computer experts, on the query formulation, through the use of Natural Language. The advantages and disadvantages of a Natural Language interaction, the Translator's modules, the linguistic problems encountered and the spatial query's particularities are presented. / Mestrado / Mestre em Ciência da Computação

Orientador : Jairo Panetta / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Ciencia da Computação / Made available in DSpace on 2018-07-14T01:56:28Z (GMT). No. of bitstreams: 1 MullerJunior_Bruno_M.pdf: 2086664 bytes, checksum: 7172d83771d9e983497bbefe376709a4 (MD5) Previous issue date: 1991 / Resumo: Este trabalho apresenta uma interface de comunicação entre um ambiente de reestruturação de programas e o usuário. A interface contém um conjunto de componentes gráficos (widgets) que permitem ao usuário interagir amigavelmente com o seu programa. Estes componentes gráficos estão divididos em dois grupos, widgets tradicionais e widgets específicos ao ambiente em questão. Dentre os widgets específicos destaca-se o widget que desenha hierarquias. Grande parte deste trabalho concentra-se no algoritmo que efetua o desenho, apresentando melhoramentos ao algoritmo conhecido na literatura / Abstract: Not informed / Mestrado / Mestre em Ciência da Computação

Orientador: Cylon Eudóxio Tricot Gonçalves da Silva / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-07-15T01:03:46Z (GMT). No. of bitstreams: 1 Fulco_Paulo_D.pdf: 2104697 bytes, checksum: f36d25523eb45dcf14c8604f517a6986 (MD5) Previous issue date: 1984 / Resumo: É desenvolvido uma técnica para calcular a densidade de estados de superfícies e interfaces. O método utilizado é o do Hamiltoniano de ligação forte, baseado no esquema de Slater-Koster. As funções de Green, surgidas do formalismo da teoria de espalhamento são desacopladas através do procedimento de renormalização. São estudadas as superfícies (100) do Si e SnO2, e a interface Si-SnO2, todas supostas ideais. Dentro desse esquema, realiza-se um estudo da origem, localização e caráter dos estados das superfícies e interface. Os resultados mostram que a técnica de renormalização reproduz o cálculo da densidade de estados efetuados por técnicas mais elaboradas. 0 teste foi realizado com as superfícies do Si e do SnO2 e a seguir foram obtidos resultados para a interface Si-SnO2 / Abstract: We develop a technique to calculate the density of state of surfaces and interfaces. The method used here is the tight-binding Hamiltonian based on the Slater-Koster approach. The Green functions, which arise from the formalism of the scattering theory, are decoupled through the renormalization's procedure. We study the ideal surface (100) of Si and SnO2, and the ideal interface Si-SnO2 This approach is used to investigate the origin, localization and behavior of the states on the surfaces and interfaces. Our results show that the renormalization technique gives the same density of state as it was found using more sophisticated techniques. We start with the surfaces of Si and SnO2 and we extend our calculations to a more complicated situation: the interface Si-SnO2 / Doutorado / Física / Doutor em Ciências

Multi-function interfaces have become increasingly pervasive and are frequently used in contexts which pose multiple demands on a single sensory modality. Assuming some degree of modularity in attentional processing and that using a different sensory channel for communication can reduce interference with critical visual tasks, one possibility is to divert some information through the touch sense. The goal of this Thesis is to advance our knowledge of relevant human capabilities and embed this knowledge into haptic communication design tools and procedures, in the interest of creating haptically supported interfaces that decrease rather than add to their users’ sensory and cognitive load. In short, we wanted to create tools and methods that would allow the creation of haptic signals (accomplished via display of either forces or vibrations) extending beyond the one bit of communication offered by current pagers and cellular phone buzzers. In our quest to create information-rich haptic signals we need to learn how to create signals that are differentiable. We also need to study ways to assign meanings to these signals and make sure that they can be perceived clearly when presented one after another even in environments where their recipient might be involved with other tasks. These needs frame the specific research goals of this thesis. Most of the results described here were obtained through the study of tactile (in the skin) rather than proprioceptive (force feedback) stimuli. We begin by presenting several methods to create, validate and contrast tactile stimulus dissimilarity data and investigate the design of a waveform intended to be a tactile perceptual intermediate between a square waveform and a triangle waveform. Next, we explore methods to create and test tactile signal-meaning associations and document a surprising ability of participants to exhibit high recall of quickly learned associations at two weeks in a first examination of longitudinal recall of tactile stimuli. We then present methods to measure tactile stimulus masking and identify crucial perceptual thresholds relating to stimulus temporal spacing in an exploration into the masking effects of common-onset vibrotactile stimuli. Finally, we present methods to test haptic and multimodal perception in simulated scenarios including a method to simulate and control cognitive workload; and provide evidence that the commonly-used device of multimodal signal reinforcement can adversely impact performance in an ongoing primary task. The research presented in this Thesis has implications for the design of signals to be used in displays that are emerging in embedded computing environments such as cars, games, cellular phones, and medical devices. / Science, Faculty of / Computer Science, Department of / Graduate