Nous étudions la minimisation du périmètre et de l'énergie de Willmore en présence de contraintes ainsi que le flot, défini par les mouvements minimisants, de l'énergie de Willmore. Les problèmes d'optimisation géométriques et les flots que nous considérons reposent sur une propriété de semi-continuité inférieure que nous pouvons assurer en prenant l'enveloppe semi-continue inférieurement des énergies incluant les contraintes.Dans la première partie de la thèse, nous étudions trois problèmes d'optimisation. Le premier concerne le périmètre avec une contrainte de connexité. Le second est un problème de reconstruction de domaine à partir de sections planaires. Cette reconstruction est basée sur la minimisation du périmètre ou de l'énergie de Willmore avec des contraintes d'inclusion-exclusion. Nous développons un modèle de champ de phase pour implémenter numériquement la reconstruction en 2D et 3D à partir de contraintes d'inclusion-exclusion variées. Le troisième problème est l'étude des propriétés des courbes fermées, confinées dans un ouvert borné du plan, minimisant l'énergie élastique (Willmore).La deuxième partie étudie le flot de l'énergie de Willmore par les mouvements minimisants. Le flot pour une surface régulière est difficile à analyser, entre autre car il peut développer des singularités en temps fini. L'enveloppe semi-continue inférieurement et les mouvements minimisants permettent de définir un flot en temps long pour des surfaces moins régulières. Ce flot est étudié dans deux situations : pour la somme de l'énergie de Willmore et du périmètre dans le plan et pour l'énergie de Willmore des fonctions radiales à profil décroissant en toute dimension / We study the minimisation with constraints of the perimeter and of the Willmore energie and the flow of the Willmore energie, defined by minimising movements. The geometric optimisation problems and flows we handle rely on a lower semicontinuous property that we enforce by taking the lower semicontinuous envelop of the energies including the constraints.In the first part of the thesis, we consider three optimisation problems. The first one deals with the perimeter and connectedness constraints in the plan. The second one is a reconstruction problem of a volumetric domain from planar slices. This reconstruction is based on the minimisation of the perimeter or of the Willmore energy with inclusion-exclusion constraints. A phase field numerical approach and experiments are implemented. The third problem is the study of closed curves confined in an open bounded subset of the plane that minimise the bending energy (or Willmore energy). The second part of the thesis studies the Willmore flow defined by minimising movements. The flow of a regular surface is complex to analyse and may develop singularities in finite time. We use the lower semicontinuous envelop of the Willmore energy and the minimising movement to define a long time flow for surfaces with less regularity. This flow is studied within two contexts: for the sum of the Willmore energy and the perimeter in the plane and for the Willmore energy of radial functions with a non-increasing profile in any dimension

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O presente trabalho analisa a dinÃmica dos processos de uso e ocupaÃÃo do espaÃo urbano de Sobral, especificamente nas Ãreas das margens do Rio Acaraà e demais cursos dâÃgua, onde foram implantados, nos Ãltimos anos, projetos de urbanizaÃÃo, provocando mudanÃas na paisagem urbana. Sobral como cidade de porte mÃdio e centro regional de grande importÃncia na zona norte do Estado do CearÃ, vem apresentando, segundo os recenseamentos, rÃpido crescimento urbano. O incremento do comÃrcio, dos serviÃos e da indÃstria atrai migrantes das Ãreas rurais do municÃpio e de outros municÃpios vizinhos, agravando os problemas sociais e ambientais urbanos. Diferentes agentes sociais atuam na produÃÃo do espaÃo urbano, conferindo à cidade um processo de expansÃo que contribui para a formaÃÃo de novas centralidades. O centro histÃrico foi tombado pelo PatrimÃnio HistÃrico e ArtÃstico Nacional âIPHAN, proporcionando um processo de renovaÃÃo urbana, atravÃs da recuperaÃÃo e preservaÃÃo das edificaÃÃes. A cidade de Sobral vem se destacando como um centro de fluxo de investimentos produtivos (industriais e de serviÃos), alÃm do crescimento do mercado imobiliÃrio. A presenÃa da Universidade Vale do Acaraà âUVA e a implantaÃÃo e modernizaÃÃo de equipamentos do setor saÃde tÃm favorecido a ampliaÃÃo de sua Ãrea de influÃncia, levando a sua polarizaÃÃo alÃm do limites do Estado. O modelo de produÃÃo do espaÃo urbano de Sobral à gerador de grandes impactos ambientais, haja vista a segregaÃÃo socioespacial urbana e o uso inadequado dos seus recursos hÃdricos.

Made available in DSpace on 2016-04-28T20:18:32Z (GMT). No. of bitstreams: 1 2009 - Alexandre Galvao.pdf: 298975 bytes, checksum: 9d22ecc92482b98f474bee4de0969bdd (MD5) Previous issue date: 2009-02-19 / Dermatobia hominis affects bovines, causing serious economic damages and of productivity for the beef cattle. The occurrence of dermatobiosis and alteration in the fertility of bulls come being currently studied with intention to evaluate its influence on the parameters of the spermatic quality. The objective of this study was to evaluate the clinical analysis of the masculine reproductive system, the testicular perimeter, the physical characteristics as motility, turbidity, intensity and spermatic concentration, and morphology of the semen. For in such a way, 18 bulls of the commercial Nelore race had been used, with age of 36 months, variation of corporal score of 6.0 to 6.5, after pre selection, following the standard of the Manual of the CBRA. The bulls had been placed in two groups: G1 (nine infested with D. hominis larvae on the scrotal skin) and G2 (nine bulls as controls), and they were submitted to the andrologic examinations in the days D24, D48, D63 and D74 and evaluated the testicular and seminal characteristics. The gotten average values of these parameters had been analyzed by the variance test, and results had indicated that it did not have significant difference (p< 0.005). These results indicate that the experimental infestation of D. hominis in the escrotal skin did not influence the spermatic quality of bulls of the Nelore race. / Dermatobia hominis afeta os bovinos, causando graves preju?zos econ?micos e de produtividade para a pecu?ria de corte. A ocorr?ncia da dermatobiose e altera??o na fertilidade de touros v?m sendo estudadas atualmente com intuito de avaliar a sua influ?ncia sobre os par?metros da qualidade esperm?tica. O objetivo deste estudo foi avaliar clinicamente o aparelho reprodutor masculino, o per?metro testicular, as caracter?sticas f?sicas (motilidade, turbilhonamento, vigor e concentra??o esperm?tica) e morfol?gicas do ejaculado. Foram utilizados 18 touros da ra?a Nelore comercial, com idade de 36 meses, com varia??o de escore corporal de 6,0 a 6,5, ap?s a pr?-sele??o seguindo o padr?o do Manual do CBRA. Os touros foram alocados em dois grupos: G1 (nove infestados com larvas de D. hominis na bolsa escrotal) e Grupo 2 ( nove touros, controle), e submetidos aos exames androl?gicos nos dias D24, D48, D63 e D74 e avaliadas as caracter?sticas testiculares e as seminais. Os valores m?dios obtidos destes par?metros foram analisados pelo teste de vari?ncia, e os resultados indicaram que n?o houve diferen?a significativa (P<0.05). Estes resultados indicam que a infesta??o experimental de D. hominis na bolsa escrotal n?o influenciou a qualidade esperm?tica de touros Nelore.

A distributed sensor using an optical fiber for detecting and locating intruders over long perimeters (>10 km) is described. Phase changes resulting from either the pressure of the intruder on the ground immediately above the buried fiber or from seismic disturbances in the vicinity are sensed by a phase-sensitive optical time-domain reflectometer (φ−OTDR). Light pulses from a cw laser operating in a single longitudinal mode and with low (MHz/min range) frequency drift are injected into one end of the single mode fiber, and the backscattered light is monitored with a photodetector. In laboratory tests with 12 km of fiber on reels, the effects of localized phase perturbations induced by a piezoelectric fiber stretcher on φ−OTDR traces were characterized. In field tests in which the sensing element is a single mode fiber in a 3-mm diameter cable buried in an 8 to 18 inch deep, 4 inch wide trench in clay soil, detection of intruders on foot up to 15 ft from the cable line was achieved. In desert terrain field tests in which the sensing fiber is in a 4.5-mm diameter cable buried in a 1 ft deep, 2.5 ft wide trench filled with loose sand, high sensitivity and consistent detection of intruders on foot and of vehicles traveling down a road near the cable line was realized over a cable length of 8.5 km and a total fiber path of 19 km in real time. In a final series of field tests in clay soil, phase changes produced by the steps of a person walking up to 15 ft away from the buried cable were observed, and vehicles traveling at 10 mph were consistently detected up to 300 ft away. Based on these results, this technology may be regarded as a candidate for providing low-cost perimeter security for nuclear power plants, electrical power distribution centers, storage facilities for fuel and volatile chemicals, communication hubs, airports, government offices, military bases, embassies, and national borders.

A distributed sensor using an optical fiber for detecting and locating intruders over long perimeters (>10 km) is described. Phase changes resulting from either the pressure of the intruder on the ground immediately above the buried fiber or from seismic disturbances in the vicinity are sensed by a phase-sensitive optical time-domain reflectometer (φ−OTDR). Light pulses from a cw laser operating in a single longitudinal mode and with low (MHz/min range) frequency drift are injected into one end of the single mode fiber, and the backscattered light is monitored with a photodetector. In laboratory tests with 12 km of fiber on reels, the effects of localized phase perturbations induced by a piezoelectric fiber stretcher on φ−OTDR traces were characterized. In field tests in which the sensing element is a single mode fiber in a 3-mm diameter cable buried in an 8 to 18 inch deep, 4 inch wide trench in clay soil, detection of intruders on foot up to 15 ft from the cable line was achieved. In desert terrain field tests in which the sensing fiber is in a 4.5-mm diameter cable buried in a 1 ft deep, 2.5 ft wide trench filled with loose sand, high sensitivity and consistent detection of intruders on foot and of vehicles traveling down a road near the cable line was realized over a cable length of 8.5 km and a total fiber path of 19 km in real time. In a final series of field tests in clay soil, phase changes produced by the steps of a person walking up to 15 ft away from the buried cable were observed, and vehicles traveling at 10 mph were consistently detected up to 300 ft away. Based on these results, this technology may be regarded as a candidate for providing low-cost perimeter security for nuclear power plants, electrical power distribution centers, storage facilities for fuel and volatile chemicals, communication hubs, airports, government offices, military bases, embassies, and national borders.

This work modifies Shamir’s algorithm by sharing a random key that is used to lock up the secret data; as against sharing the data itself. This is significant in cloud computing, especially with homomorphic encryption. Using web design, the resultant scheme practically globalises secret sharing with authentications and inherent secondary applications. The work aims at improving cybersecurity via a joint exploitation of human factors and technology; a human-centred cybersecurity design as opposed to technology-centred. The completed functional scheme is tagged CDRSAS. The literature on secret sharing schemes is reviewed together with the concepts of human factors, trust, cyberspace/cryptology and an analysis on a 3-factor security assessment process. This is followed by the relevance of passwords within the context of human factors. The main research design/implementation and system performance are analysed, together with a proposal for a new antidote against 419 fraudsters. Two twin equations were invented in the investigation process; a pair each for secret sharing and a risk-centred security assessment technique. The building blocks/software used for the CDRSAS include Shamir’s algorithm, MD5, HTML5, PHP, Java, Servlets, JSP, Javascript, MySQL, JQuery, CSS, MATLAB, MS Excel, MS Visio, and Photoshop. The codes are developed in Eclipse IDE, and the Java-based system runs on Tomcat and Apache, using XAMPP Server. Its code units have passed JUnit tests. The system compares favourably with SSSS. Defeating socio-cryptanalysis in cyberspace requires strategies that are centred on human trust, trust-related human attributes, and technology. The PhD research is completed but there is scope for future work.

ÁGUIAR JÚNIOR,Paulo Rocha. A cidade e o rio: produção do espaço urbano em Sobral - Ceará. 2005. 199 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Programa de Pós-Graduação em Desenvolvimento e Meio Ambiente - PRODEMA, Fortaleza-CE, 2005 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-04-08T13:35:08Z No. of bitstreams: 1 2005_dis_praguiarjúnior.pdf: 6251610 bytes, checksum: dceaf179dba70c4ba1c9542569fdbbdd (MD5) / Approved for entry into archive by Nádja Goes(nmoraissoares@gmail.com) on 2016-04-08T13:35:28Z (GMT) No. of bitstreams: 1 2005_dis_praguiarjúnior.pdf: 6251610 bytes, checksum: dceaf179dba70c4ba1c9542569fdbbdd (MD5) / Made available in DSpace on 2016-04-08T13:35:28Z (GMT). No. of bitstreams: 1 2005_dis_praguiarjúnior.pdf: 6251610 bytes, checksum: dceaf179dba70c4ba1c9542569fdbbdd (MD5) Previous issue date: 2005 / O presente trabalho analisa a dinâmica dos processos de uso e ocupação do espaço urbano de Sobral, especificamente nas áreas das margens do Rio Acaraú e demais cursos d’água, onde foram implantados, nos últimos anos, projetos de urbanização, provocando mudanças na paisagem urbana. Sobral como cidade de porte médio e centro regional de grande importância na zona norte do Estado do Ceará, vem apresentando, segundo os recenseamentos, rápido crescimento urbano. O incremento do comércio, dos serviços e da indústria atrai migrantes das áreas rurais do município e de outros municípios vizinhos, agravando os problemas sociais e ambientais urbanos. Diferentes agentes sociais atuam na produção do espaço urbano, conferindo à cidade um processo de expansão que contribui para a formação de novas centralidades. O centro histórico foi tombado pelo Patrimônio Histórico e Artístico Nacional –IPHAN, proporcionando um processo de renovação urbana, através da recuperação e preservação das edificações. A cidade de Sobral vem se destacando como um centro de fluxo de investimentos produtivos (industriais e de serviços), além do crescimento do mercado imobiliário. A presença da Universidade Vale do Acaraú –UVA e a implantação e modernização de equipamentos do setor saúde têm favorecido a ampliação de sua área de influência, levando a sua polarização além do limites do Estado. O modelo de produção do espaço urbano de Sobral é gerador de grandes impactos ambientais, haja vista a segregação socioespacial urbana e o uso inadequado dos seus recursos hídricos.

O objetivo deste trabalho foi identificar e analisar como os estudantes compreendem os conceitos de área e perímetro. A escolha do tema se deu durante nossa experiência docente ao observarmos a dificuldade de estudantes ao resolverem problemas em geometria. Para atingir tal objetivo trabalhou-se com uma turma do nono ano do ensino fundamental, durante nove horas-aula, uma sequência de atividades. Estes alunos participantes da pesquisa pertencem a uma escola pública da rede estadual, situada próximo ao centro de Porto Alegre, Rio Grande do Sul. Nossa principal base teórica foi a Teoria dos Campos Conceituais de Gérard Vergnaud e os estágios da aprendizagem de grandezas propostos por Plaza e Gómez. Com o auxílio desta teoria elaboramos as atividades, e procuramos entender como os estudantes compreendem as ideias de área e perímetro. Nestas atividades foram propostos problemas que discutiam o tema, os estudantes eram convidados a medir, visualizar construções geométricas, aplicar os conceitos e executarem cálculos. A partir destes dados foram feitas discussões sobre o porquê dos alunos apresentarem dificuldades e/ou êxitos nos problemas. Por analisarmos as resoluções de cada aluno, podemos afirmar que nossa metodologia foi qualitativa voltada a um estudo de caso. A partir das análises destas resoluções, embasado em Plaza e Gómez, Vergnaud e em outros autores que discutiram o tema, elaboramos uma sequência didática como uma proposta que auxilie os estudantes a compreenderem área e perímetro. Verificamos que muitos dos erros cometidos pelos estudantes estavam ligados a um mau entendimento dos conceitos envolvidos nos problemas, e que a maioria, durante a resolução das atividades, tentava aplicar as definições e fórmulas mesmo em situações que não fazia sentido aplicá-las. Verificamos, também, algumas indicações de que uma reconstrução destes conceitos, através da sequência proposta, é possível. / The aim of this paper has been to identify and analyse how the students understand the concepts of area and perimeter. The choice of this topic happened during our teaching experience while observing the difficulty of the students in solving geometry problems. To reach this aim, we have worked with a ninth year of primary school class, during nine classes, using a sequence of activities. These students, who participated in the study, belong to a state school, located near Porto Alegre downtown, Rio Grande do Sul. Our main theoretical framework was Gérard Vergnaud’s Theory of Conceptual Fields and the stages of quantities of learning proposed by plaza and Gómez. With the help of this theory, we elaborated the activities and tried to comprehend how the students understand the ideas of area and perimeter. In these activities, problems that discussed the topic were proposed, in which the students were invited to measure, visualise geometric constructions, apply the concepts and execute the calculations. From this data, discussions on the reason the students have difficulties and/or success with the problems happened. As we analysed the answers of each student, we can affirm that our methodology was a qualitative study with case study approach. From the analyses of these answers, based on Vergnaud, Plaza e Gómez and other authors who have discussed the topic, we elaborated a didactic sequence with a proposal that helps the students to understand area and perimeter. It was verified that many of the mistakes made by the students were connected to a poor understanding of the concepts involved in the problems, and, most of them, during the solution of the problems, tried to apply the definitions and formulas even when it didn’t make any sense. It was also verified that some indicatives of a reconstruction of these concepts, through the proposed sequence, is possible.

Orientador: Prof. Dr. Márcio Fabiano da Silva / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Mestrado Profissional em Matemática em Rede Nacional, 2016.

O objetivo deste trabalho foi identificar e analisar como os estudantes compreendem os conceitos de área e perímetro. A escolha do tema se deu durante nossa experiência docente ao observarmos a dificuldade de estudantes ao resolverem problemas em geometria. Para atingir tal objetivo trabalhou-se com uma turma do nono ano do ensino fundamental, durante nove horas-aula, uma sequência de atividades. Estes alunos participantes da pesquisa pertencem a uma escola pública da rede estadual, situada próximo ao centro de Porto Alegre, Rio Grande do Sul. Nossa principal base teórica foi a Teoria dos Campos Conceituais de Gérard Vergnaud e os estágios da aprendizagem de grandezas propostos por Plaza e Gómez. Com o auxílio desta teoria elaboramos as atividades, e procuramos entender como os estudantes compreendem as ideias de área e perímetro. Nestas atividades foram propostos problemas que discutiam o tema, os estudantes eram convidados a medir, visualizar construções geométricas, aplicar os conceitos e executarem cálculos. A partir destes dados foram feitas discussões sobre o porquê dos alunos apresentarem dificuldades e/ou êxitos nos problemas. Por analisarmos as resoluções de cada aluno, podemos afirmar que nossa metodologia foi qualitativa voltada a um estudo de caso. A partir das análises destas resoluções, embasado em Plaza e Gómez, Vergnaud e em outros autores que discutiram o tema, elaboramos uma sequência didática como uma proposta que auxilie os estudantes a compreenderem área e perímetro. Verificamos que muitos dos erros cometidos pelos estudantes estavam ligados a um mau entendimento dos conceitos envolvidos nos problemas, e que a maioria, durante a resolução das atividades, tentava aplicar as definições e fórmulas mesmo em situações que não fazia sentido aplicá-las. Verificamos, também, algumas indicações de que uma reconstrução destes conceitos, através da sequência proposta, é possível. / The aim of this paper has been to identify and analyse how the students understand the concepts of area and perimeter. The choice of this topic happened during our teaching experience while observing the difficulty of the students in solving geometry problems. To reach this aim, we have worked with a ninth year of primary school class, during nine classes, using a sequence of activities. These students, who participated in the study, belong to a state school, located near Porto Alegre downtown, Rio Grande do Sul. Our main theoretical framework was Gérard Vergnaud’s Theory of Conceptual Fields and the stages of quantities of learning proposed by plaza and Gómez. With the help of this theory, we elaborated the activities and tried to comprehend how the students understand the ideas of area and perimeter. In these activities, problems that discussed the topic were proposed, in which the students were invited to measure, visualise geometric constructions, apply the concepts and execute the calculations. From this data, discussions on the reason the students have difficulties and/or success with the problems happened. As we analysed the answers of each student, we can affirm that our methodology was a qualitative study with case study approach. From the analyses of these answers, based on Vergnaud, Plaza e Gómez and other authors who have discussed the topic, we elaborated a didactic sequence with a proposal that helps the students to understand area and perimeter. It was verified that many of the mistakes made by the students were connected to a poor understanding of the concepts involved in the problems, and, most of them, during the solution of the problems, tried to apply the definitions and formulas even when it didn’t make any sense. It was also verified that some indicatives of a reconstruction of these concepts, through the proposed sequence, is possible.