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Menšík, Marek. "Hodnocení informačních systémů." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2009. http://www.nusl.cz/ntk/nusl-222209.
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This diploma thesis deals with information systems evaluation from user and producer aspects. The theoretical part presents current trends and actual ways of using, including practical application used in real firms. The practical part is focused on proposals and changes for concrete producer of information system.
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Weise, Jillian. "Semi Semi Dash." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1258477843.
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Santos, Ana Paula Balthazar dos. "SESI." Florianópolis, SC, 1995. http://repositorio.ufsc.br/xmlui/handle/123456789/76254.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas. Programa de Pós-Graduação em Sociologia PolíticaMade available in DSpace on 2012-10-16T08:41:10Z (GMT). No. of bitstreams: 1 252763.pdf: 1226602 bytes, checksum: dfac1a0f1b4e297c09a2767a09897a9a (MD5)
Este estudo analisa o Serviço Social da Indústria (SESI) - entidade de atuação nacional - que declara ter como objetivo proporcionar "bem-estar ao trabalhador da indústria" através de um amplo trabalho de assistência nas áreas da saúde, da educação, do serviço social, do lazer e da cooperação e assistência, além da promoção de concursos como o Prêmio Talento Brasileiro e a Campanha Operário Brasil (antigo Concurso Operário Padrão). O SESI ganha especial relevância a partir do momento em que se percebe que sua criação, em 1946, faz parte de uma estratégia sócio-política do empresariado industrial diante do contexto histórico da época permeado por conflitos sociais, econômicos e políticos. Nesse sentido, considera-se que o empresariado criou uma entidade assistencial que ao proporcionar "bem-estar aos trabalhadores e seus dependentes" teria como objetivo realizar a estratégia de "paz social" ("harmonia social"). A assistência passa a ser o meio de atingir um fim maior que é garantir que as relações entre patrões e empregados (capital-trabalho) sejam menos conflitantes e mais harmoniosas. Para este trabalho, além de estudos teóricos, foram realizadas uma pesquisa documental e uma pesquisa de campo. Ademais, a análise partiu do âmbito geral para o específico na medida em que começa resgatando a história do SESI no Brasil bem como sua estrutura funcional (administração, recursos, regulamentos e personalidade jurídica), passando para a análise no estado de Santa Catarina e no Centro de Atividades do SESI na Grande Florianópolis. Nesse estado, o SESI começou a instalar-se em 1948, justamente num período em que ele também vivenciava conflitos sócio-econômicos e políticos. Assim, além de recuperar a origem do SESI catarinense, foi dado destaque à atuação da entidade, tanto em termos do tipo de trabalho desenvolvido e da amplitude desse, como a forma como ele é executado. Também, foi vista a relação entre o SESI e a FIESC. Tendo essas questões como pano de fundo, buscou-se avaliar o efetivo alcance dos objetivos empresariais atribuídos ao SESI, através do significado que o trabalhador - seu usuário - dá à respectiva entidade. Para atingir esse objetivo, foi traçada a caracterização sócio-econômica do trabalhador que se utiliza do SESI e seu perfil político-ideológico a partir de um conjunto de indicadores (Concurso Operário Padrão, associação de funcionários, greve, sindicato e partido político). Foi resgatada, também, a percepção que esse industriário atribui ao seu próprio trabalho, ao empresariado e, principalmente, ao SESI. A partir deste estudo, verificou-se, entre outras coisas, que a tendência predominante entre os trabalhadores usuários do SESI é não saber ou ter vaga idéia sobre quem o criou. Também desconhecem quem dirige e/ou administra a entidade, mas afirmam que os recursos mantenedores dos serviços e atividades sesianos são provenientes das indústrias. A assistência é considerada o objetivo central do SESI, e é avaliada positivamente pelos usuários. Constatou-se, também, que o SESI se afirma positivamente através do trabalho que desenvolve e que de certa forma é mais presente e forte no espaço e no tempo cotidiano dos trabalhadores do que outras instituições, pois tende a ocupar o lugar de outras organizações próprias de reivindicação e representação política e corporativa (sindicato, partido político, associação). Assim, avaliou-se que sua força e seu conteúdo ideológico estão na realização dos seus serviços e atividades, os quais vão ao encontro das necessidades dos trabalhadores. Nesse sentido, seu objetivo de "harmonia social" tende a ser realizado mais através da ação do que propriamente do seu discurso, como se pensava ao se iniciar esse estudo. O trabalho do SESI seria a tradução concreta do seu discurso. Enfim, o SESI é uma organização que faz parte de um conjunto de espaços, de meios, de instituições que vão construindo e reforçando a ideologia e o poder empresarial dentro de um sistema integrado às demais organizações deste segmento. É mais um indicador da crescente influência do empresariado na sociedade contemporânea.
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Lima, Reinaldo Feio. "Aprendizagem de estat?stica na EJA com tecnologia : uma sequ?ncia did?tica com base nos registros de representa??o semi?tica." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2014. http://tede2.pucrs.br/tede2/handle/tede/3479.
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Previous issue date: 2014-02-28This research has as one of its objectives to understand the contributions of a didactic sequence of graphical and tabular representations with the use of technologies for learning Statistics in EJA. The purpose was to answer the following question: "What contributions a didactic sequence, using activities with technologies that include reading and interpreting graphs and tables in the microcosm of the mathematics classroom, can provide for learning Statistics in EJA? In this sense, the methodology of this research was developed along the lines of the French Didactic Engineering researcher Mich?le Artigue (1995). As a theoretical framework adopted the Representation Theory of Semiotics Records Duval (2003), as well as studies of the levels of reading comprehension and interpretation of graphs Curcio (1989) and Wainer (1995) tables. Data collection occurred through field notes (journal of the researcher), direct observations, photographs, audio recordings and video of all class, records produced by the students during the activities, questionnaires and diagnostic tests. Our study subjects were 15 volunteer students from Stage 4 (old 7th and 8th grade) elementary school in a public school in the municipality of Thailand / PA, who attended the sessions, which occurred during normal school hours with permission of faculty and from the school. In general, it was found that the activities of reading and interpreting tables and graphs performed by students of the EJA, allowed the use and exploitation of different registers of semiotic representation, such as natural language, numerical, treatment, conversion and coordination between records, besides the improvement of reading and interpreting data. It follows therefore that the involvement of students during all stages of research and dialogue among themselves and with their teacher were important determinants for the success of research and the promotion of learning. In short, without claiming to extrapolate the results beyond the research universe , since the study sample was small , it is believed that the research problem was answered because it was found that the instructional sequence mediated by technology particularly in this case the worksheet was crucial for learning the contents of Statistics proposed and consequently to job success .
Esta pesquisa tem como um dos seus objetivos compreender as contribui??es de uma sequ?ncia did?tica sobre representa??es tabular e gr?fica com uso de tecnologias para a aprendizagem de Estat?stica na EJA. O prop?sito era responder ? seguinte quest?o: Que contribui??es uma sequ?ncia did?tica, utilizando atividades com tecnologias, que contemplem leitura e interpreta??o de gr?ficos e tabelas no microcosmo da sala de aula de matem?tica, pode oferecer para a aprendizagem de Estat?stica na EJA?. Nesse sentido, a metodologia dessa pesquisa foi desenvolvida nos moldes da Engenharia Did?tica da pesquisadora francesa Mich?le Artigue (1995). Como referencial te?rico adotou-se a Teoria dos Registros de Representa??o Semi?tica de Duval (2003), bem como os estudos dos n?veis de compreens?o de leitura e interpreta??o de gr?ficos de Curcio (1989) e o de tabelas de Wainer (1995). A coleta de dados se deu por meio de notas de campo (di?rio do pesquisador), observa??es diretas, fotografias, grava??es em ?udio e v?deo de todas as aulas, registros produzidos pelos alunos ao longo das atividades, question?rios e testes diagn?sticos. Nossos sujeitos de pesquisa foram 15 alunos volunt?rios da 4? Etapa (antiga 7? e 8? s?rie) do Ensino Fundamental de uma escola p?blica do munic?pio de Tail?ndia/PA, que participaram das sess?es, que ocorreram durante o hor?rio normal de aulas sob autoriza??o dos professores e da dire??o da escola. Em termos gerais, verificou-se que as atividades de leitura e interpreta??o de tabelas e gr?ficos realizados pelos alunos da EJA, possibilitaram a utiliza??o e explora??o de diferentes registros de representa??o semi?tica, como a da linguagem natural, da num?rica, do tratamento, da convers?o e da coordena??o entre os registros, al?m do aprimoramento de ler e interpretar dados. Conclui-se assim que o envolvimento dos alunos durante todas as etapas da investiga??o bem como o di?logo entre eles e deles com o professor foram aspectos determinantes para o sucesso da investiga??o e para a promo??o da aprendizagem. Em suma, sem ter a pretens?o de extrapolar os resultados apresentados para al?m do universo da pesquisa, uma vez que a amostra investigada foi pequena, acredita-se que o problema de pesquisa foi respondido, pois se constatou que a sequ?ncia did?tica mediada pela tecnologia, particularmente nesse caso a planilha, foi determinante para aprendizagem dos conte?dos de Estat?stica propostos e, consequentemente, para o sucesso do trabalho.
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Forshaw, Gareth William. "Semi-automatic matching of semi-structured data updates." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/12930.
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Includes bibliographical references.Data matching, also referred to as data linkage or field matching, is a technique used to combine multiple data sources into one data set. Data matching is used for data integration in a number of sectors and industries; from politics and health care to scientific applications. The motivation for this study was the observation of the day-to-day struggles of a large non-governmental organisation (NGO) in managing their membership database. With a membership base of close to 2.4 million, the challenges they face with regard to the capturing and processing of the semi-structured membership updates are monumental. Updates arrive from the field in a multitude of formats, often incomplete and unstructured, and expert knowledge is geographically localised. These issues are compounded by an extremely complex organisational hierarchy and a general lack of data validation processes. An online system was proposed for pre-processing input and then matching it against the membership database. Termed the Data Pre-Processing and Matching System (DPPMS), it allows for single or bulk updates. Based on the success of the DPPMS with the NGO’s membership database, it was subsequently used for pre-processing and data matching of semi-structured patient and financial customer data. Using the semi-automated DPPMS rather than a clerical data matching system, true positive matches increased by 21% while false negative matches decreased by 20%. The Recall, Precision and F-Measure values all improved and the risk of false positives diminished. The DPPMS was unable to match approximately 8% of provided records; this was largely due to human error during initial data capture. While the DPPMS greatly diminished the reliance on experts, their role remained pivotal during the final stage of the process.
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Chakrabortty, Abhishek. "Robust Semi-Parametric Inference in Semi-Supervised Settings." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493516.
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In this dissertation, we consider semi-parametric estimation problems under semi-supervised (SS) settings, wherein the available data consists of a small or moderate sized labeled data (L), and a much larger unlabeled data (U). Such data arises naturally from settings where the outcome, unlike the covariates, is expensive to obtain, a frequent scenario in modern studies involving large electronic databases. It is often of interest in SS settings to investigate if and when U can be exploited to improve estimation efficiency, compared to supervised estimators based on L only.
In Chapter 1, we propose a class of Efficient and Adaptive Semi-Supervised Estimators (EASE) for linear regression. These are semi-non-parametric imputation based two-step estimators adaptive to model mis-specification, leading to improved efficiency under model mis-specification, and equal (optimal) efficiency when the linear model holds. This adaptive property is crucial for advocating safe use of U. We provide asymptotic results establishing our claims, followed by simulations and application to real data.
In Chapter 2, we provide a unified framework for SS M-estimation problems based on general estimating equations, and propose a family of EASE estimators that are always as efficient as the supervised estimator and more efficient whenever U is actually informative for the parameter of interest. For a subclass of problems, we also provide a flexible semi-non-parametric imputation strategy for constructing EASE. We provide asymptotic results establishing our claims, followed by simulations and application to real data.
In Chapter 3, we consider regressing a binary outcome (Y) on some covariates (X) based on a large unlabeled data with observations only for X, and additionally, a surrogate (S) which can predict Y with high accuracy when it assumes extreme values. Assuming Y and S both follow single index models versus X, we show that under sparsity assumptions, we can recover the regression parameter of Y versus X through a least squares LASSO estimator based on the subset of the data restricted to the extreme sets of S with Y imputed using the surrogacy of S. We provide sharp finite sample performance guarantees for our estimator, followed by simulations and application to real data.Biostatistics
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Garraway, William Dale. "Semi-quantaloids." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq24844.pdf.
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Hawryluk, Lynda J. "Semi-detached /." View thesis, 1997. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030916.102851/index.html.
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Quast, Thijs. "Utilizing unlabeled data in cell type identification : A semi-supervised learning approach to classification." Thesis, Linköpings universitet, Statistik och maskininlärning, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-165996.
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Recent research in bioinformatics has presented multiple cell type identification meth- dologies using single cell RNA sequence data (scRNA-seq). However, a consensus on which cell typing methodology consistently demonstrates superior performance remains absent. Additionally, very few studies approach cell type identification through a semi- supervised learning study, whereby the information in unlabeled data is leveraged to train an enhanced classifier. This paper presents cell annotation methodologies through self- learning and graph-based semi-supervised learning, in both raw count scRNA-seq data as well as in a latent embedding. I find that a self-learning framework enhances perfor- mance compared to a solely supervised learning classifier. Additionally, modelling on the latent data representations consistently outperforms modelling on the original data. The results show an overall accuracy of 96.12%, whereas additional models achieve an average precision rate of 95.12% and an average recall rate of 94.40%. The semi-supervised learn- ing approaches in this thesis compare favourable to scANVI in terms of accuracy, average precision rate, average recall rate and average f1-score. Moreover, results for alternative scenarios, in which cell types among training and test data do not perfectly overlap, are reported in this thesis.
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Moussu, Carole. "Étude des propriétés holographiques des semi-conducteurs semi-magnétiques /." Paris : École nationale supérieure des télécommunications, 1999. http://catalogue.bnf.fr/ark:/12148/cb370471782.
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Zaccak, Gabriel (Gabriel Gabra). "Wrapster : semi-automatic wrapper generation for semi-structured websites." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40537.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (leaves 69-74).
Many information sources on the Web are semi-structured; hence there is an opportunity for automatic tools to process and extract their information for easy access through a uniform interface language. Wrapper generation is the creation of wrappers which contains scripts that extract and integrate data from data sources, mostly from Web data sources due to the large amount of data available on the World Wide Web. Despite ongoing efforts to automate the process of wrapper generation, wrappers frequently break due to formatting and layout changes in data sources. This thesis presents Wrapster, a new system that semi-automatically generates wrappers for semi-structured Web sources, improves wrapper robustness, and eliminates the need for programming skills and, to a large extent, the process of script creation. Wrapster's novel component is the repairing module that constantly checks if any wrapper script has failed and repairs the failing wrapper's script using stored extracted instances. In addition, Wrapster provides an interactive Web user interface to control the wrapper generation process, edit the generated wrappers, and test their scripts. Wrapster is being tested on the START Question Answering system; however, it is a generic tool to be used by any QA system that uses the Web as its knowledge base.
by Gabriel Zaccak.
S.M.
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Caldas, Miguel. "A separation axiom between semi-T° and semi-T1." Pontificia Universidad Católica del Perú, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/96144.
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The author introduces a new separation axiom and studies some of their basic properties. The implication of these new separation axiom among themselves and with the well known axioms semi-T2 semi-T1 and semi-T0 are obtained.
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Moussu, Carole. "Etude des propriétés holographiques des semi-conducteurs semi-magnetiques." Paris, ENST, 1998. http://www.theses.fr/1998ENST0021.
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Cette étude est réalisée dans le cadre de la recherche de nouveaux matériaux pour l'holographie en temps réel, technique à la base de nombreuses applications, notamment en traitement optique du signal et de l'image. L'holographie dynamique dans les semi-conducteurs semi-magnétiques est étudiée théoriquement (modèle analytique et numérique) et expérimentalement (mesures du rendement de diffraction dans cdmnte en mélange a quatre ondes (679 nm) en régime nanoseconde). Nous décrivons également le comportement du matériau en présence d'un champ électrique statique dans le but d'obtenir du couplage à deux ondes. Il ressort de cette étude que la durée de vie des réseaux d'indice inscrits dans cdmnte est de l'ordre de la microseconde, beaucoup plus longue que dans les semi-conducteurs classiques grâce au ralentissement de la diffusion des porteurs induit par le piégeage des électrons sur les sites des ions manganèse. Le mécanisme du a la concentration de trous dans la bande de valence est caractérise par une bonne sensibilité (s = 1,6. 10 6 m 2/j), de forts rendements de diffraction (18% pour 3,4 mj/cm 2) quasiment constants pour des angles d'écriture allant de 0 à 25 degrés, une variation d'indice linéaire en fonction de la fluence des faisceaux d'écriture ne saturant pas jusqu'à des valeurs probablement très supérieures a 6. 10 5 et un temps de réponse limite par la durée des impulsions d'écriture. L'effet photo réfractif induit par la répartition locale des porteurs pourra être néglige, la variation d'indice saturant très vite a 1,5. 10 6. En régime nanoseconde, les résultats expérimentaux concordent parfaitement avec les résultats théoriques. Ces matériaux sont envisageables pour toute application à l'holographie en temps réel ne nécessitant pas de transfert d'énergie : conjugaison de phase, corrélation, il est très probable que hymne présenterait les mêmes propriétés holographiques, ce qui permettrait d'envisager des applications du visible à l'infrarouge lointain.
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Keyantuo, Valentin. "Semi-groupes distributions, semi-groupes integres et problemes d'evolution." Besançon, 1992. http://www.theses.fr/1992BESA2003.
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Le but du travail est l'etude des semi-groupes integres et leurs applications aux equations d'evolution lineaires dans les espaces de banach. Certaines equations d'evolution connues ne sont en effet pas resolubles directement par la methode des semi-groupes fortement continus. C'est le cas de l'equation des ondes et de l'equation de schroedinger sur les espaces l#p, p=2. Au chapitre i, on introduit les semi-groupes n fois integres locaux et, en utilisant la transformation de laplace finie, on obtient une caracterisation complexe de leurs generateurs. De tels problemes ne peuvent en general pas etre traites par les techniques usuelles de transformation de laplace. On etablit une correspondance complete entre les semi-groupes integres locaux et les semi-groupes distributions, ainsi que le lien avec les semi-groupes fortement continus sur les espaces de frechet. Le chapitre ii etudie le lien entre les problemes de cauchy d'ordre un et deux avec application a l'equation des ondes sur l#p(), ouvert borne de r#n. Au chapitre iii, en s'inspirant de la methode de descente de hadamard, on montre que la (fermeture de la) somme de n generateurs de fonctions cosinus qui commutent sur un espace de banach e engendre une fonction cosinus (n-1)/2 fois integree sur e. D'autre part, des methodes de representation permettent d'obtenir encore une fonction cosinus si on se place dans un cadre hilbertien. Le quatrieme chapitre est consacre a l'interpolation et a l'extrapolation des c-semi-groupes. L'interpolation, deja apparente dans les chapitres precedents, montre que dans l'etude d'un probleme concret, le choix de l'espace fonctionnel est fondamental
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Bouziad, Ahmed. "Contribution à la théorie des semi-groupes semi-topologiques." Rouen, 1989. http://www.theses.fr/1989ROUES007.
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Les travaux présentés dans cette thèse ont trait aux semigroupes semitopologiques et peuvent se répartir en trois groupes: le premier groupe concerne les structures algébriques et topologique d'un semigroupe semitopologique compact admettant un sous-groupe dense, l'existence de points de continuité de la multiplication d'un groupe semitopologique de Baire cosmique, l'existence de points de continuité d'une action de semilattis topologique compact dans un espace compact. Le deuxième groupe concerne la structure du semigroupe des applications d'un ensemble dans lui-même, quand ce semigroupe est muni d'une topologie rendant les translations à droite continues. Enfin, dans le troisième groupe de ces travaux, nous considérons un semigroupe discret et présentons, comme espaces de filtres, les compactifications suivantes de ce semigroupe: la compactification faiblement presque-périodique O-dimensionnelle, la compactification presque-périodique zéro-dimensionnelle, la compactification presque-périodique. Diverses applications sont données; en particulier, des problèmes ouverts de W. Ruppert et G. Lallement sont résolus
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HUGONNARD-BRUYERE, SERGE. "Effet faraday photo-induit dans les semi-conducteurs semi-magnetiques." Palaiseau, Ecole polytechnique, 1994. http://www.theses.fr/1994EPXX0014.
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La rotation photo-induite du plan de polarisation d'une onde lumineuse par une onde laser intense en presence d'un champ magnetique longitudinal (configuration faraday) est une des voies de la commutation tout-optique. Cette classe d'effets est d'autant plus prometteuse que certains composes (les semi-conducteurs semi-magnetiques ii1-xmxvi) sont le siege de rotations faraday lineaires dont le caractere geant (3000/t/mm pres du gap) se retrouve dans les effets photo-induits. Les semi-conducteurs semi-magnetiques sont des semi-conducteurs de type ii-vi dont une fraction des cations est substituee par des ions magnetiques. Leurs proprietes magneto-optiques geantes sont dues a l'interaction d'echange sp-d existant entre les ions magnetiques et les porteurs des bandes. Nous proposons une alternative aux modeles precedents sur le spectre de la rotation faraday lineaire grace a une description en terme de susceptibilite microscopique faisant intervenir une dependance en vecteur reciproque de l'interaction d'echange sp-d. Dans un second temps, nous etudions les effets photo-induits du point de vue theorique et experimental. Nous presentons nos resultats resolus en temps (superieur a la nanoseconde), en fonction du champ magnetique, de la longueur d'onde de la sonde, de la temperature et de la concentration en ions manganese dans cdmnte et znmnte massifs (1 mm). A basse temperature (t<15k), domine la composante due a une modification d'origine thermique de l'aimantation. A plus haute temperature (jusqu'a 300k), demeure l'effet de saturation d'indice du a la presence de porteurs photo-excites dans les bandes. Les diverses dependances sont analysees et mesurees, ainsi que la dynamique de l'effet en fonction de la concentration en mn, de la temperature et du procede de fabrication (brigdman et fusion de zone)
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Tran, Khanh-Hung. "Semi-supervised dictionary learning and Semi-supervised deep neural network." Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASP014.
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Depuis les années 2010, l’apprentissage automatique (ML) est l’un des sujets qui retient beaucoup l'attention des chercheurs scientifiques. De nombreux modèles de ML ont démontré leur capacité produire d’excellent résultats dans des divers domaines comme Vision par ordinateur, Traitement automatique des langues, Robotique… Toutefois, la plupart de ces modèles emploient l’apprentissage supervisé, qui requiert d’un massive annotation. Par conséquent, l’objectif de cette thèse est d’étudier et de proposer des approches semi-supervisées qui ont plusieurs avantages par rapport à l’apprentissage supervisé. Au lieu d’appliquer directement un classificateur semi-supervisé sur la représentation originale des données, nous utilisons plutôt des types de modèle qui intègrent une phase de l’apprentissage de représentation avant de la phase de classification, pour mieux s'adapter à la non linéarité des données. Dans le premier temps, nous revisitons des outils qui permettent de construire notre modèles semi-supervisés. Tout d’abord, nous présentons deux types de modèle qui possèdent l’apprentissage de représentation dans leur architecture : l’apprentissage de dictionnaire et le réseau de neurones, ainsi que les méthodes d’optimisation pour chaque type de model, en plus, dans le cas de réseau de neurones, nous précisons le problème avec les exemples contradictoires. Ensuite, nous présentons les techniques qui accompagnent souvent avec l’apprentissage semi-supervisé comme l’apprentissage de variétés et le pseudo-étiquetage. Dans le deuxième temps, nous travaillons sur l’apprentissage de dictionnaire. Nous synthétisons en général trois étapes pour construire un modèle semi-supervisée à partir d’un modèle supervisé. Ensuite, nous proposons notre modèle semi-supervisée pour traiter le problème de classification typiquement dans le cas d’un faible nombre d’échantillons d’entrainement (y compris tous labellisés et non labellisés échantillons). D'une part, nous appliquons la préservation de la structure de données de l’espace original à l’espace de code parcimonieux (l’apprentissage de variétés), ce qui est considéré comme la régularisation pour les codes parcimonieux. D'autre part, nous intégrons un classificateur semi-supervisé dans l’espace de code parcimonieux. En outre, nous effectuons le codage parcimonieux pour les échantillons de test en prenant en compte aussi la préservation de la structure de données. Cette méthode apporte une amélioration sur le taux de précision par rapport à des méthodes existantes. Dans le troisième temps, nous travaillons sur le réseau de neurones. Nous proposons une approche qui s’appelle "manifold attack" qui permets de renforcer l’apprentissage de variétés. Cette approche est inspirée par l’apprentissage antagoniste : trouver des points virtuels qui perturbent la fonction de coût sur l’apprentissage de variétés (en la maximisant) en fixant les paramètres du modèle; ensuite, les paramètres du modèle sont mis à jour, en minimisant cette fonction de coût et en fixant les points virtuels. Nous fournissons aussi des critères pour limiter l’espace auquel les points virtuels appartiennent et la méthode pour les initialiser. Cette approche apporte non seulement une amélioration sur le taux de précision mais aussi une grande robustesse contre les exemples contradictoires. Enfin, nous analysons des similarités et des différences, ainsi que des avantages et inconvénients entre l’apprentissage de dictionnaire et le réseau de neurones. Nous proposons quelques perspectives sur ces deux types de modèle. Dans le cas de l’apprentissage de dictionnaire semi-supervisé, nous proposons quelques techniques en inspirant par le réseau de neurones. Quant au réseau de neurones, nous proposons d’intégrer "manifold attack" sur les modèles génératifsSince the 2010's, machine learning (ML) has been one of the topics that attract a lot of attention from scientific researchers. Many ML models have been demonstrated their ability to produce excellent results in various fields such as Computer Vision, Natural Language Processing, Robotics... However, most of these models use supervised learning, which requires a massive annotation. Therefore, the objective of this thesis is to study and to propose semi-supervised learning approaches that have many advantages over supervised learning. Instead of directly applying a semi-supervised classifier on the original representation of data, we rather use models that integrate a representation learning stage before the classification stage, to better adapt to the non-linearity of the data. In the first step, we revisit tools that allow us to build our semi-supervised models. First, we present two types of model that possess representation learning in their architecture: dictionary learning and neural network, as well as the optimization methods for each type of model. Moreover, in the case of neural network, we specify the problem with adversarial examples. Then, we present the techniques that often accompany with semi-supervised learning such as variety learning and pseudo-labeling. In the second part, we work on dictionary learning. We synthesize generally three steps to build a semi-supervised model from a supervised model. Then, we propose our semi-supervised model to deal with the classification problem typically in the case of a low number of training samples (including both labelled and non-labelled samples). On the one hand, we apply the preservation of the data structure from the original space to the sparse code space (manifold learning), which is considered as regularization for sparse codes. On the other hand, we integrate a semi-supervised classifier in the sparse code space. In addition, we perform sparse coding for test samples by taking into account also the preservation of the data structure. This method provides an improvement on the accuracy rate compared to other existing methods. In the third step, we work on neural network models. We propose an approach called "manifold attack" which allows reinforcing manifold learning. This approach is inspired from adversarial learning : finding virtual points that disrupt the cost function on manifold learning (by maximizing it) while fixing the model parameters; then the model parameters are updated by minimizing this cost function while fixing these virtual points. We also provide criteria for limiting the space to which the virtual points belong and the method for initializing them. This approach provides not only an improvement on the accuracy rate but also a significant robustness to adversarial examples. Finally, we analyze the similarities and differences, as well as the advantages and disadvantages between dictionary learning and neural network models. We propose some perspectives on both two types of models. In the case of semi-supervised dictionary learning, we propose some techniques inspired by the neural network models. As for the neural network, we propose to integrate manifold attack on generative models
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Räbiger, Dirk. "Semi-präemptives Transportieren." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976461102.
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Hruschka, Harald. "Semi-parametrische Marktanteilsmodellierung." SFB Adaptive Information Systems and Modelling in Economics and Management Science, WU Vienna University of Economics and Business, 2000. http://epub.wu.ac.at/736/1/document.pdf.
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In der vorliegenden empirischen Untersuchung erreichen Marktanteilsmodelle mit semi-parametrischen additiven Markenattraktionen bessere Anpassungsmaße sowohl nach einem Informationskriterium wie AIC, das ein Modell für die Anzahl verbrauchter Freiheitsgrade bestraft, als auch nach mittels Kreuzvalidierung oder Bootstrapping bestimmten Fehlermaßen. Die höhere Flexibilität gegenüber strikt parametrischen Modellen führt zu einer verläßlicheren Messung der Effekte von Marketing-Instrumenten. Außerdem unterscheiden sich marginale Effekte und Preiselastizitäten, die auf Grundlage des semi-parametrischen Modells berechnet werden, qualitativ von jenen, die man für die parametrischen Alternativen erhält. Das flexiblere Marktanteilsmodell impliziert unterschiedliche, mit Gewinnsteigerungen verbundene optimale Entscheidungen, wie mit Hilfe des Lösungskonzepts Fictitious Play bestimmte Preise und Gewinne zeigen. (Autorenreferat)Series: Report Series SFB "Adaptive Information Systems and Modelling in Economics and Management Science"
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Persson, Daniel. "Sequi : Tredimensionell sequencer." Thesis, Konstfack, Grafisk Design & Illustration, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-4707.
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Music production software has a strong tradition of two-dimensional graphical user interface (GUI), in which the time line is represented as a flat composition either horizontally (from left to right) or vertically (from top to bottom). In my degree work titled Sequi, I approach music composition from a different angle. Instead of a two-dimensional time line with only two possibly ways of progression (forward or backward) I constructed a three-dimensional GUI with the maximum of four different ways of progression from any given point in a composition. The height axis is used to describe time-intervals (the time between downbeats) and the wide and depth axes are used to describe progression from one sound to another.
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Shepler, Anne V. "Semi-invariant forms /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9936834.
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Caldas, Miguel. "Espacios semi T ½." Pontificia Universidad Católica del Perú, 2014. http://repositorio.pucp.edu.pe/index/handle/123456789/96067.
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En este trabajo investigamos el axioma de separación en espacios semi T ½ y estudiamos algunas de sus propiedades básicas. Además de esto, analizamos las relaciones entre este axioma de separación con los bien conocidos axiomas para los espacios semi T2, semi T1 y semi To .
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Jordan, Douglas Mark. "Semi-insulating silicon." Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711627.
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Pouliot, George. "A Variable Resolution Nonhydrostatic Global Atmospheric Semi-implicit Semi-Lagrangian Model." NCSU, 2000. http://www.lib.ncsu.edu/theses/available/etd-20000403-180910.
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ABSTRACTPOULIOT, GEORGE. A Variable Resolution Nonhydrostatic Global Atmospheric Semi-implicit Semi-Lagrangian Model. (Under the direction of Dr. Fredrick H.M. Semazzi.)The objective of this project is to develop a variable-resolution finite difference adiabatic global nonhydrostatic semi-implicit semi-Lagrangian (SISL) model based on the fully compressible nonhydrostatic atmospheric equations. To achieve this goal, a three-dimensional variable resolution dynamical core was developed and tested.The main characteristics of the dynamical core can be summarized as follows: Spherical coordinates were used in a global domain. A hydrostatic/nonhydrostatic switch was incorporated into the dynamical equations to use the fully compressible atmospheric equations. A generalized horizontal variable resolution grid was developed and incorporated into the model. For a variable resolution grid, in contrast to a uniform resolution grid, the order of accuracy of finite difference approximations is formally lost but remains close to the order of accuracy associated with the uniform resolution grid provided the grid stretching is not too significant. The SISL numerical scheme was implemented for the fully compressible set of equations. In addition, the generalized minimum residual (GMRES) method with restart and preconditioner was used to solve the three-dimensional elliptic equation derived from the discretized system of equations. The three-dimensional momentum equation was integrated in vector-form to incorporate the metric terms in the calculations of the trajectories. Using global re-analysis data for a specific test case, the model was compared to similar SISL models previously developed. Reasonable agreement between the model and the other independently developed models was obtained. The Held-Suarez test for dynamical cores was used for a long integration and the model was successfully integrated for up to 1200 days. Idealized topography was used to test the variable resolution component of the model. Nonhydrostatic effects were simulated at grid spacings of 400 meters with idealized topography and uniform flow. Using a high-resolution topographic data set and the variable resolution grid, sets of experiments with increasing resolution were performed over specific regions of interest. Using realistic initial conditions derived from re-analysis fields, nonhydrostatic effects were significant for grid spacings on the order of 0.1 degrees with orographic forcing. If the model code was adapted for use in a message passing interface (MPI) on a parallel supercomputer today, it was estimated that a global grid spacing of 0.1 degrees would be achievable for a global model. In this case, nonhydrostatic effects would be significant for most areas.A variable resolution grid in a global model provides a unified and flexible approach to many climate and numerical weather prediction problems. The ability to configure the model from very fine to very coarse resolutions allows for the simulation of atmospheric phenomena at different scales using the same code. We have developed a dynamical core illustrating the feasibility of using a variable resolution in a global model.
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Lemonidis, Panayiotis. "Global optimization algorithms for semi-infinite and generalized semi-infinite programs." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43200.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2008.Includes bibliographical references (p. 235-249).
The goals of this thesis are the development of global optimization algorithms for semi-infinite and generalized semi-infinite programs and the application of these algorithms to kinetic model reduction. The outstanding issue with semi-infinite programming (SIP) was a methodology that could provide a certificate of global optimality on finite termination for SIP with nonconvex functions participating. We have developed the first methodology that can generate guaranteed feasible points for SIP and provide e-global optimality on finite termination. The algorithm has been implemented in a branch-and-bound (B&B) framework and uses discretization coupled with convexification for the lower bounding problem and the interval constrained reformulation for the upper bounding problem. Within the framework of SIP we have also proposed a number of feasible-point methods that all rely on the same basic principle; the relaxation of the lower-level problem causes a restriction of the outer problem and vice versa. All these methodologies were tested using the Watson test set. It was concluded that the concave overestimation of the SIP constraint using McCormcick relaxations and a KKT treatment of the resulting expression is the most computationally expensive method but provides tighter bounds than the interval constrained reformulation or a concave overestimator of the SIP constraint followed by linearization. All methods can work very efficiently for small problems (1-3 parameters) but suffer from the drawback that in order to converge to the global solution value the parameter set needs to subdivided. Therefore, for problems with more than 4 parameters, intractable subproblems arise very high in the B&B tree and render global solution of the whole problem infeasible.
(cont.) The second contribution of the thesis was the development of the first finite procedure that generates guaranteed feasible points and a certificate of e-global optimality for generalized semi-infinite programs (GSIP) with nonconvex functions participating. The algorithm employs interval extensions on the lower-level inequality constraints and then uses discretization and the interval constrained reformulation for the lower and upper bounding subproblems, respectively. We have demonstrated that our method can handle the irregular behavior of GSIP, such as the non-closedness of the feasible set, the existence of re-entrant corner points, the infimum not being attained and above all, problems with nonconvex functions participating. Finally, we have proposed an extensive test set consisting of both literature an original examples. Similar to the case of SIP, to guarantee e-convergence the parameter set needs to be subdivided and therefore, only small examples (1-3 parameters) can be handled in this framework in reasonable computational times (at present). The final contribution of the thesis was the development of techniques to provide optimal ranges of valid reduction between full and reduced kinetic models. First of all, we demonstrated that kinetic model reduction is a design centering problem and explored alternative optimization formulations such as SIP, GSIP and bilevel programming. Secondly, we showed that our SIP and GSIP techniques are probably not capable of handling large-scale systems, even if kinetic model reduction has a very special structure, because of the need for subdivision which leads to an explosion in the number of constraints. Finally, we propose alternative ways of estimating feasible regions of valid reduction using interval theory, critical points and line minimization.
by Panayiotis Lemonidis.
Ph.D.
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Noll, Olaf. "Polymerisierbare Semi-Rotaxane auf Basis von Cyclodextrinen." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=965442799.
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Baroni, Alessandra Faria. "Semi-desidratação congelamento e semi-desidratação secagem de cebola (Allium cepa L.)." [s.n.], 1997. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255132.
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Orientador: Miriam Dupas HubingerDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: ONeste trabalho foi estudada a desidratação osmótica de pedaços de cebola em soluções salinas como pré-tratamento para as operações de congelamento e secagem. A influência da concentração da solução desidratante e a temperatura do banho osmótico foram utilizados para a avaliação da cinética da desidratação osmótica. Valores dos coeficientes de transferência de massa, obtidos através de ajuste de um modelo de cinética de reação de primeira ordem aos dados experimentais foram analisados. Através de uma solução da Lei de Fick, coeficientes de difusão da água e do sal foram obtidos e relacionados com as variáveis do processo. Os resultados mostram que é possível remover até 12% da umidade inicial, nas condições do ensaio e que o processo sofre mais influência da concentração que da temperatura. Os coeficientes de transferência de massa mostram que quanto maior a concentração e a temperatura, maior será a saída de água e entrada de soluto. Os valores de difusividade obtidos foram similares aos relatados pela literatura. Duas condições de desidratação osmótica foram utilizadas nos ensaios de congelamento e secagem: concentração do banho osmótico 10% e 15% (1h ,22°C). Através de calorimetria diferencial de varredura foi possível obter a entalpia de fusão, temperatura de início de fusão, temperatura de fusão, teor de água não congelável e calor específico aparente. Ensaios de descongelamento foram realizados para avaliar a perda de peso após o processo. Observou-se redução de até 24% no montante de energia necessário para a mudança de fase no congelamento nas amostra pré-tratadas, bem como menores valores de calor específico aparente. As análises do descongelamento mostram uma melhoria da qualidade do produto que sofreu o pré-tratamento.A determinação da cinética de secagem em camada fina foi feita a três níveis de temperatura (40, 50 e 60°C). Coeficientes de difusão da umidade foram obtidos pelo ajuste dos dados experimentais através da solução da equação da difusão. A influência da temperatura foi determinada através da equação de Arrhenius. Os resultados mostram que a imersão da cebola em solução salina 10% antes da secagem, aumenta a taxa de secagem e melhora a aparência do produto final.
Abstract: The present work investigated the osmotic dehydration of onion slices in salt solutions as a pre-treatment to freezing and drying. The effects of salt solution concentration and osmotic bath temperature on the kinetics of the process were evaluated. Mass transfer coefficients, obtained by fitting of a first order reaction kinetic equation were obtained and analyzed. Using a solution of Fick's law of diffusion, water and salt effective diffusion coefficients were obtained and related to process variables. Results showed that for the processing employed in the present study, a reduction up to 12% in the sample initial moisture could be obtained. It is also observed that the salt solution concentration showed a more significantly effect on the process where compared to the bath temperature. U sing mass transfer analysis was observed that higher temperatures and solution concentrations resulted in increases in both water removal and solute penetration. The effective diffusion coefficients obtained were similar to those found in literature. Two osmotic dehydration conditions were chosen in the freezing and drying tests: bath solution concentrations of 10% and 15% (w/w) NaCl (1h, 22°C). Using differential scanning calorimetry, the melting heat, initial melting point, melting peak, unftozen water and apparent specific heat could be obtained. Thawing tests were performed to evaluate the weight loss after the process. It was observed a reduction of up to 24% of energy consumption to freeze water in the pre-treated samples, as well as low values of apparent specific heat. Soaking the samples prior to freezing gave a better quality after thawing. The thin-layer drying kinetic at three temperatures (40, 50 and 60°C) were determined. Moisture diffusion coefficients were obtained by fitting of experimental data to a solution of Fick' s law of diffusion. The effects of temperature on drying were evaluated using Arrhenius equation. The results showed that soaking onion slices in 10% NaCl solution prior to drying increases the drying rate and improves the general appearance of final product.
Mestrado
Mestre em Engenharia de Alimentos
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Zurr, Ionat. "Growing semi-living art." University of Western Australia. School of Architecture, Landscape and Visual Arts, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0125.
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In 1996 Oron Catts and Ionat Zurr coined the term Semi-Livings to describe the living tissue constructs that are grown/constructed out of tissues taken from complex organisms and maintained alive with the aid of technological intervention. The Semi-Livings refers mainly to living tissue constructs that have no biomedical purpose. In the case of Catts and Zurr these evocative entities are created for the sole purpose of art. The Semi-Livings are unique examples of a growing class of objects/subjects that are increasingly populating our made environment. This thesis is the story of these tissue constructs as well as the techno-scientific project which sustains them alive and further articulates their meanings and purposes. This investigation is conducted in times of rapid developments in the life sciences and their applied technologies, when the humanist view of human separation and domination over nature is under great challenge. The thesis explores issues concerning the nature of living fragments of bodies and how they force us humans to reassess our understandings of life. It narrates the history of partial life, beginning a century ago, mainly in the bio-medical field and the fiction stories it created, to the times when actual semi-livings exist, not only in laboratories and tissue banks, but also in factories, museums, zoos and art galleries. The new and re-emerging ethical questions raised by such a phenomenon are discussed. The role of the artist working with living (and semi-living) materials in the context of post-capitalism and genohype is interrogated. The aim is to reveal and establish a new field within the arts Tissue Art pioneered by the artists of the Tissue Culture & Art project (Catts and Zurr) and the ensuing development of SymbioticA, an Artistic Research Laboratory, at the School of Anatomy and Human Biology of the University of Western Australia. We are living in times when new understandings of life through advances in scientific knowledge and new abilities to manipulate life through applied technologies are increasingly incompatible with traditional cultural and ontological perceptions of life. This gap between current (and potential) bio-technological practices and cultural beliefs is the niche explored by the Tissue Culture & Art project (TC&A). The TC&A's Semi-Livings are conceptual prototypes of a new kind of
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Amornsinlaphachai, Pensri. "Updating semi-structured data." Thesis, Northumbria University, 2007. http://nrl.northumbria.ac.uk/3422/.
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The Web has had a tremendous success with its support for the rapid and inexpensive exchange of information. A considerable body of data exchange is in the form of semi- structured data such as the eXtensible Markup Language (XML). XML, an effective standard to represent and exchange semi-structured data on the Web, is used ubiquitously in almost all areas of information technology. Most researchers in the XML area have concentrated on storing, querying and publishing XML while not many have paid attention to updating XML; thus the XML update area is not fully developed. We propose a solution for updating XML as a representation of semi-structured data. XML is updated through an object-relational database (ORDB) to exploit the maturity of the relational engine and the newer object features of the OR technology. The engine is used to enforce constraints during the updating of the XML whereas the object features are used to handle the XML hierarchical structure. Updating XML via ORDB makes it easier to join XML documents in an update and in turn joins of XML documents make it possible to keep non-redundant data in multiple XML documents. This thesis contributes a solution for the update of XML documents via an ORDB to advance our understanding of the XML update area. Rules for mapping XML structure and constraints to an ORDB schema are presented and a mechanism to handle XML cardinality constraint is provided. An XML update language, an extension to XQuery, has been designed and this language is translated into the standard SQL executed on an ORDB. To handle the recursive nature of XML, a recursive function updating XML data is translated into SQL commands equipped with a programming capability. A method is developed to reflect the changes from the ORDB to XML documents. A prototype of the solution has been implemented to help validate our approach. Experimental study to evaluate the performance of XML update processing based on the prototype has been conducted. The experimental results show that updating multiple XML documents storing non-redundant data yields a better performance than updating a single XML document storing redundant data; an ORDB can take advantage of this by caching data to a greater extent than a native XML database. The solution of updating XML documents via an ORDB can solve some problems in existing update methods as follows. Firstly, the preservation of XML constraints is handled by the ORDB engine. Secondly, non-redundant data is stored in linked XML documents; thus the problem of data inconsistency and low performance caused by data redundancy are solved. Thirdly, joins of XML documents are converted to joins of tables in SQL. Fourthly, fields or tables involved in regular path expressions can be tackled in a short time by using mapping data. Finally, a recursive function is translated into SQL commands equipped with a programming capability.
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Hernandez, Armando, Rick Galeano, and Mario Escobar. "The semi-submersible network." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/27844.
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This is a qualitative and quantitative study of the semi-submersible network operating out of the southwestern portion of Colombia. This study combines both of these aspects to provide strategic options for kinetic, non-kinetic, and a combination of both measures for commanders to use to disrupt or destroy this network. Empirical historical data provide the qualitative information essential to understanding the present-day situation. The quantitative data are a combination of geo-spatial analysis, link analysis, social network analysis, and temporal analysis. Together, these paint a picture of the main source of revenue for the FARC. Open-source intelligence was used for all of the analysis which, when combined with other forms of intelligence, may illuminate the network and portray it in a new light.
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Jones, James Arthur. "Semi-automatic fault localization." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22609.
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Thesis (Ph. D.)--Computing, Georgia Institute of Technology, 2008.Committee Chair: Harrold, Mary Jean; Committee Member: Orso, Alessandro; Committee Member: Pande, Santosh; Committee Member: Reiss, Steven; Committee Member: Rugaber, Spencer.
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Bachelder, Laura Govoni 1971. "Semi-finished modular cells." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/63220.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2002.Includes bibliographical references (p. 62-64).
This thesis subject is a pre-fabricated element (cell): a system that employs natural, light, and economic materials to produce a near-finished portion of a building. The intent is to introduce sustainable design into construction industry through prefabrication. The cell has been envisioned both for permanent and temporary usage: in the former case, preeminently as a construction element, while in the latter, as a finished unit. In both cases, the cell is mainly an assembly of smaller components that can possibly be recycled and reused after dismantling without additional reprocessing. The main idea behind the cell is to employ simple and small elements to achieve sustainable design.
by Laura Govoni Bachelder.
S.M.
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Luque, Rodrigo Gheller. "Árvores BSP semi-ajustáveis." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2005. http://hdl.handle.net/10183/17349.
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A etapa de broad-phase para a detecção de colisão em cenas compostas de n objetos que se movimentam é um problema desafiador, pois enumerar os pares de colisão revela uma complexidade quadrática. Estruturas de dados espaciais são desenvolvidas para acelerar o processo, mas muitas vezes a natureza estática dessas estruturas dificulta o manejo de cenas dinâmicas. Nesse trabalho, é proposta uma nova estrutura chamada de árvore BSP semi-ajustável para representar cenas compostas de milhares de objetos dinâmicos. Um algoritmo de agendamento avalia onde a árvore BSP torna-se desbalanceada, usa várias estratégias para alterar os planos de corte e atualizações preguiçosas para reduzir os custos de reconstrução. É mostrado que a árvore não precisa uma total reconstrução mesmo em cenas altamente dinâmicas, ajustando-se e mantendo propriedades desejáveis de balanceamento e profundidade.The broad-phase step of collision detection in scenes composed of n moving objects is a challenging problem because enumerating collision pairs has an inherent O(n²) complexity. Spatial data structures are designed to accelerate this process, but often their static nature makes it difficult to handle dynamic scenes. In this work we propose a new structure called Semi-Adjusting BSP-tree for representing scenes composed of thousands of moving objects. A scheduling algorithm evaluates locations where the BSP-tree becomes unbalanced, uses several strategies to alter cutting planes, and defers updates based on their re-structuring cost. We show that the tree does not require a complete re-structuring even in highly dynamic scenes, but adjusts itself while maintaining desirable balancing and height properties.
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Stride, Christopher B. "Semi-parametric density estimation." Thesis, University of Warwick, 1995. http://wrap.warwick.ac.uk/109619/.
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The local likelihood method of Copas (1995a) allows for the incorporation into our parametric model of influence from data local to the point t at which we are estimating the true density function g(t). This is achieved through an analogy with censored data; we define the probability of a data point being considered observed, given that it has taken value xi, as where K is a scaled kernel function with smoothing parameter h. This leads to a likelihood function which gives more weight to observations close to t, hence the term ‘local likelihood’. After constructing this local likelihood function and maximising it at t, the resulting density estimate f(tiOt) can be described as semi-parametric in terms of its limits with respect to h. As h--oo, it approximates a standard parametric' fit f(I.O) whereas when h decreases towards 0, it approximates the non - parametric kernel density estimate. My thesis develops this idea, initially proving its asymptotic superiority over the standard parametric estimate under certain conditions. We then consider the improvements possible by making smoothing parameter h a function of /, enabling our semi parametric estimate to vary from approximating y(l) in regions of high density to f(t,0) in regions where we believe the true density to be low. Our improvement in accuracy is demonstrated in both simulated and real data examples, and the limits with respect to h and the new adaption parameter oo are examined. Methods for choosing h and oo are given and evaluated, along with a procedure for incorporating prior belief about the true form of the density into these choices. Further practical examples illustrate the effectiveness of I these ideas when applied to a wide range of data sets.
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Junkes, Berenice da Silva. "Índice semi-empírico topológico." Florianópolis, SC, 2003. http://repositorio.ufsc.br/xmlui/handle/123456789/85075.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em Química.Made available in DSpace on 2012-10-20T15:08:00Z (GMT). No. of bitstreams: 1 198987.pdf: 5942141 bytes, checksum: 7bb584e2f7fedf5689044108457ed464 (MD5)
Neste estudo um novo descritor molecular - Índice Semi-Empírico Topológico (IET) - foi desenvolvido, a fim de estabelecer correlações quantitativas entre estrutura e propriedade (QSPR), para diferentes classes de compostos. Este Índice foi desenvolvido e otimizado para prever a retenção cromatográfica de alcenos ramificados, alcanos metil ramificados produzidos por insetos e álcoois saturados, em fases estacionárias de baixa polaridade. Foi avaliada, também, a habilidade de previsão do IET para a retenção cromatográfica de álcoois, aldeídos e cetonas em fases estacionárias mais polares. Os estudos preliminares aplicando o IET a diferentes propriedades/atividades apresentaram resultados promissores para a aplicação futura deste novo método. Para alcenos e álcoois foram obtidas correlações entre o IET e as propriedades (ponto de ebulição normal, refração molar, volume molar, calor de combustão, calor de vaporização molar e coeficiente de partição octanol/água), com valores de r > 0,94. As correlações quantitativas estrutura-atividade (QSAR) foram testadas para álcoois saturados, onde as atividades biológicas investigadas foram: atividade narcótica sobre larvas das cracas, toxicidade em aranhas e tomates e odor (r > 0,88). A qualidade dos resultados obtidos neste trabalho para a previsão de diferentes propriedades/atividades, empregando o IET como descritor molecular, pode ser considerada como uma importante etapa na direção de estudos futuros em QSAR/QSPR/QSRR.
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Souza, Érica Silva. "Índice semi-empírico eletrotopológico." Florianopolis, SC, 2009. http://repositorio.ufsc.br/xmlui/handle/123456789/93342.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2009.Made available in DSpace on 2012-10-24T20:44:44Z (GMT). No. of bitstreams: 1 267247.pdf: 662168 bytes, checksum: 25d11e6c890c6089a8f2d2e413494306 (MD5)
Neste trabalho, um novo índice topológico é proposto, baseado na observação de que a retenção cromatográfica de alcanos e alcenos depende fortemente da carga atômica líquida dos átomos de carbono dessas moléculas. O índice semi-empírico eletrotopológico ( ) é aplicado para prever a retenção cromatográfica de hidrocarbonetos alifáticos, aldeídos, cetonas e ésteres. A correlação linear simples entre os índices de retenção cromatográficos e os valores dos para alcanos e alcenos é de boa qualidade e estabilidade interna conforme os parâmetros estatísticos: r= 0,9990; s=10,74; N=179. Os modelos de QSRR para aldeídos e cetonas usando o são também de boa qualidade: r = 0,9994; s = 10,31; N = 15 para aldeídos e r = 0,9997; s = 11,72; N = 42 para cetonas. Modelos de QSRR utilizando para ésteres alifáticos em diferentes fases estacionárias apresentam parâmetros estatísticos variando entre: r=0,9990 a 0,9959; e s=7,65 a 16,02. Um modelo combinado para a predição do índice de retenção usando o índice proposto e a polaridade de McReynolds é de boa qualidade estatística conforme os parâmetros de mérito: r = 0,9978; s = 12,94; N = 500. Este índice codifica tanto a distribuição de carga quanto detalhes estruturais, relacionados ao tamanho, ramificação e presença de heteroátomos, possibilitando novos estudos de QSPR para diferentes funções orgânicas.
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Coelho, Frederico Gualberto Ferreira. "Semi-supervised feature selection." Universidade Federal de Minas Gerais, 2013. http://hdl.handle.net/1843/BUOS-97NJ9S.
Full textAbstract:
As data acquisition has become relatively easy and inexpensive, data
sets are becoming extremely large, both in relation to the number
of variables, and on the number of instances. However, the same is
not true for labeled instances . Usually, the cost to obtain these
labels is very high, and for this reason, unlabeled data represent the
majority of instances, especially when compared with the amount
of labeled data. Using such data requires special care, since several
problems arise with the dimensionality increase and the lack of labels.
Reducing the size of the data is thus a primordial need. In the midst
of its outstanding features, usually we found irrelevant and redundant
variables, which can and should be eliminated. In attempt to identify
these variables, to despise the unlabeled data, implementing only
supervised strategies, is a loss of any structural information that
can be useful. Likewise, ignoring the labeled data by implementing
only unsupervised methods is also a loss of information. In this
context, the application of a semi-supervised approach is very suitable,
where one can try to take advantage of the best benefits that each
type of data has to offer. We are working on the problem of semi-supervised feature selection by two different approaches, but it may
eventually complement each other later. The problem can be addressed
in the context of feature clustering, grouping similar variables and
discarding the irrelevant ones. On the other hand, we address the
problem through a multi-objective approach, since we have arguments
that clearly establish its multi-objective nature. In the first approach, a similarity measure capable to take into account both the labeled and unlabeled data, based on mutual information, is developed as well, a criterion based on this measure for clustering and discarding variables. Also the principle of homogeneity between labels and data clusters is exploited and two semi-supervised feature selection methods are developed. Finally a mutual information estimator for a mixed set of discrete and continuous variables is developed as a secondary contribution. In the multi-objective approach, the proposal is try to solve both the problem of feature selection and function approximation, at the same time. The proposed method includes considering different weight vector norms for each layer of a Multi Layer Perceptron (MLP) neural networks, the independent training of each layer and the definition of objective functions, that are able to eliminate irrelevant features.Como a aquisição de dados tem se tornado relativamente mais fácil e barata, o conjunto de dados tem adquirido dimensões extremamente grandes, tanto em relação ao número de variáveis, bem como em relação ao número de instâncias. Contudo, o mesmo não ocorre com os rótulos de cada instância. O custo para se obter estes rótulos é, via de regra, muito alto, e por causa disto, dados não rotulados são a grande maioria, principalmente quando comparados com a quanti-dade de dados rotulados. A utilização destes dados requer cuidados especiais uma vez que vários problemas surgem com o aumento da dimensionalidade e com a escassez de rótulos. Reduzir a dimensão dos dados é então uma necessidade primordial. Em meio às suas características mais relevantes, usualmente encontramos variáveis redundantes e mesmo irrelevantes, que podem e devem ser eliminadas. Na procura destas variáveis, ao desprezar os dados não rotulados, implementando-se apenas estratégias supervisionadas, abrimos mão de informações estruturais que podem ser úteis. Da mesma forma, desprezar os dados rotulados implementando-se apenas métodos não supervisionados é igualmente disperdício de informação. Neste contexto, a aplicação de uma abordagem semi-supervisionada é bastante apropriada, onde pode-se tentar aproveitar o que cada tipo de dado tem de melhor a oferecer. Estamos trabalhando no problema de seleção de características semi-supervisionada através de duas abordagens distintas, mas que podem, eventualmente se complementarem mais à frente. O problema pode ser abordado num contexto de agrupamento de características, agrupando variáveis semelhantes e desprezando as irrelevantes. Por outro lado, podemos abordar o problema através de uma metodologia multiobjetiva, uma vez que temos argumentos estabelecendo claramente esta sua natureza multiobjetiva. Na primeira abordagem, uma medida de semelhança capaz de levar em consideração tanto os dados rotulados como os não rotulados, baseado na informação mútua, está sendo desenvolvida, bem como, um critério, baseado nesta medida, para agrupamento e eliminação de variáveis. Também o princípio da homogeneidade entre os rótulos e os clusters de dados é explorado e dois métodos semissupervisionados de seleção de características são desenvolvidos. Finalmente um estimador de informaçã mútua para um conjunto misto de variáveis discretas e contínuas é desenvolvido e constitue uma contribuição secundária do trabalho. Na segunda abordagem, a proposta é tentar resolver o problema de seleção de características e de aproximação de funções ao mesmo tempo. O método proposto inclue a consideração de normas diferentes para cada camada de uma rede MLP, pelo treinamento independente de cada camada e pela definição de funções objetivo que sejam capazes de maximizar algum índice de relevância das variáveis.
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Wacrenier, Pierre-André. "Semi-commutations et reconnaissabilité." Lille 1, 1993. http://www.theses.fr/1993LIL10018.
Full textAbstract:
Les commutations partielles ont ete utilisees en 1977 par A. Mazurkiewicz pour etudier le comportement de processus paralleles. La notion de semi-commutations generalise celle de commutation partielle ; les semi-commutations permettent de modeliser les programmes a memoire partagee de type producteur/consommateur. Dans une premiere partie nous etudions la composition de deux fonctions de semi-commutation: nous caracterisons les couples de fonctions de semi-commutation dont la composition est une fonction de semi-commutation. Grace a cette caracterisation nous obtenons, en particulier, une caracterisation decidable des semi-commutations confluentes. La seconde partie de ce memoire est consacree aux morphismes pour semi-commutations; ceux-ci permettent de specifier le parallelisme a differents niveaux d'abstraction. Nous etudions les morphismes pour semi-commutations qui preservent la reconnaissabilite et caracterisons les morphismes des monoides de semi-traces qui peuvent etre simules par des transductions rationnelles.
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Gonzalez, Dominique. "Décomposition des semi commutations." Lille 1, 1993. http://www.theses.fr/1993LIL10002.
Full textAbstract:
L'apparition du parallélisme dans les calculs et les programmes a entraîné le besoin de modèles formels performants dont les plus utilisés sont les réseaux de Pétri, les langages traces et, plus récemment, les semi-commutation. La question qui vient naturellement à l'esprit quand on étudie une nouvelle opération est : peut-elle être simulée aux moyens d'opérations plus simples ? Nous répondons donc ici à la question : peut-on décomposer les semi-commutations ? Nous démontrons que toute semi-commutation peut être vue comme la composition de semi-commutations élémentaires que nous appelons semi-commutations atomiques. Nous proposons un algorithme effectif de décomposition. Nous pouvons alors donner une nouvelle démonstration d'un théorème permettant de décomposer toute semi-commutations en homomorphismes non effacants, homomorphismes inverses et commutations partielles. Nous établissons une caractérisation des semi-commutations qui préservent la famille des langages multicompteurs : les semi-commutations à compteurs. Elles ont, entre autres, la propriété d'être composables. Elles nous permettent également de résoudre certains problèmes de décidabilité. Nous fournissons quelques résultats quant à la complexité de l'algorithme de décomposition des semi-commutations, certains résultats étant démontrés grâce à l'utilisation des semi-commutations atomiques maximales qui ont une structure proche des semi-commutations à compteurs. Nous proposons enfin un algorithme simple qui permet de décider si un rationnel (dont on connaît l'automate réduit déterministe) est fermé par une semi-commutation donnée
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Bardin, Lisa. "Monocouches d'alcanes semi-fluorés." Paris 6, 2010. http://www.theses.fr/2010PA066114.
Full textAbstract:
Nous avons étudié des monocouches d’alcanes semi-fluorés déposées à l’interface eau-air. Pour toutes les architectures moléculaires étudiées, nous avons mis en évidence par diffraction des rayons X rasants que la monocouche ne devient jamais homogène, même pour des pressions de surface supérieures à la pression de collapse. En effet, les molécules s’auto-assemblent en domaines de quelques milliers de molécules mais parfaitement définis. Quand la pression est non nulle, ces domaines s’organisent en réseau hexagonal de grand paramètre (30-40 nm). A l’échelle moléculaire, nous avons confirmé la présence d’un réseau hexagonal (de paramètre 0,58 nm) des chaînes fluorées. La structure en domaines explique la faible portée de l’ordre de ce réseau moléculaire. La densité électronique des domaines peut être modélisée par une pyramide de disques circulaires dont la base est entourée d’une couronne. On en déduit que la composante hydrogénée des molécules est en contact avec l’eau et que la composante fluorée en contact avec l’air. La couronne, de densité électronique intermédiaire, pourrait être à l’origine de la non coalescence des domaines maintenant ainsi la monocouche inhomogène. La structure hexagonale des domaines n’est cependant pas conservée après transfert sur substrat solide. Pour ce faire, nous avons développé une nouvelle procédure de dépôt, plus simple et plus rapide, qui permet de retrouver ce réseau hexagonal sur substrat solide
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Xystouris, George. "SETI follow-up observations." Thesis, Uppsala universitet, Observationell astrofysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-294436.
Full textAbstract:
The G-HAT team (G-HAT: Glimpsing Heat from Alien Technologies) compiled a catalogue of 93 galaxies that could host Kardashev-III civilizations [Griffith et al., 2015], using data from the WISE space telescope. Their method was based on the detection of the civilization's "waste heat": as any physical process takes place, heat is being released to the environment and it can be detected as an excess of the IR flux of the object. Garrett [2015] combined the data from the G-HAT catalogue with the 20cm flux from the NRAO VLA Sky Survey (NVSS) and 9 objects with an anomalous flux excess at IR wavelengths were identied. This work is based on the the needed follow-up observations for each of those 9 sources. This work is divided into three parts: in the first part we explain the theory of the "waste heat" search method, in the second part we give details about our submitted proposal for a submillimeter follow-up observation of NGC0814, using the Atacama Pathnder EXperiment (APEX) and in the third part we present a strategy for the required follow-up observations for the rest of the candidates.
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Premdjee, B. "Semi-synthesis of glycoproteins." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1434897/.
Full textAbstract:
Glycosylation is a prevalent form of post translational modification, believed to occur on over 50% of human proteins. Homogeneous forms of glycoproteins are essential for developing an understanding of how activity is mediated at a structural level. As biological origins of glycoproteins give rise to complex mixtures of glycoforms, homogeneous glycoprotein production has become an important goal. As chemical protein synthesis is often limited to sequences of 30-50 residues, access to large native glycoproteins is currently restricted to fragment based approaches. Protein semi-synthesis enables the preparation of larger proteins which can be difficult to obtain through chemical synthesis alone. Consequently, a general semi-synthetic strategy towards N-glycoproteins has been proposed and demonstrated on Interferon-β-1 (IFNβ), a 166 residue glycoprotein. A three fragment strategy was designed, relying on the chemical synthesis of a short glycopeptide segment and recombinant expression of the two flanking domains. Homogeneity was established through the chemical synthesis of a glycopeptide containing a natively linked N-acetylglucosamine (GlcNAc), also enabling the selective transfer of complex oligosaccharides. After cloning and expression, the recombinant fragments were functionalised to allow assembly of the protein using Native Chemical Ligation. These desired protein modifications were achieved through the application of highly chemoselective reactions. These reactions were also applied towards the generation of N-glycopeptides compatible with the ligation strategy. Further to this, existing methods enabling the direct synthesis of functionalised N-glycopeptides were also explored. After glycopeptide synthesis, endoglycosidase A enabled the transfer of oligosaccharides to the N-acetylglucosamine motif. This has allowed the preparation of the desired IFNβ glycopeptide as well as a glycosylated variant of glucagon like peptide-1. To expand the utility of endoglycosidase methodology, a novel sugar nucleotide was synthesised to facilitate the incorporation of a sialyl galactose mimic onto N-glycans. The resulting oligosaccharides may serve as novel substrates for endoglycosidases in the preparation of N-glycoprotein mimics.
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Monk, Kristina B. "Semi-Lagrangian, Semi-Implicit Solutions of the Shallow Water Equations in One Dimension." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/26236.
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MASSOT, ISABELLE MULLER JEAN-FRANCOIS. "CONTRIBUTION A L'ETUDE SEMI-QUANTITATIVE DE SEMI-CONDUCTEURS PAR MICROSONDE A IMPACT LASER /." [S.l.] : [s.n.], 1990. ftp://ftp.scd.univ-metz.fr/pub/Theses/1990/Isabelle.Massot.SMZ9019.pdf.
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Massot, Isabelle. "Contribution à l'étude semi-quantitative de semi-conducteurs par microsonde à impact laser." Metz, 1990. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1990/Isabelle.Massot.SMZ9019.pdf.
Full textAbstract:
Dans le domaine des techniques d'analyse de surface, la microsonde à impact laser lamma possède des capacités analytiques tout à fait intéressantes: ponctualité, rapidité et simplicité des analyses (pas de préparation d'échantillon pour la microsonde lamma 1000), analyse de toutes sortes d'échantillons solides, détection de tous les ions d'une même polarité sans limitation de masse, bonne sensibilité de détection. Une grande partie du travail effectué au cours de cette thèse a été consacrée au développement instrumental de la microsonde lamma 1000 de l'usine IBM France de Corbeil-Essonnes, de telle sorte que les résultats issus de cet équipement sont depuis tout à fait fiables et reproductibles. Ainsi, les améliorations apportées permettent maintenant de disposer d'un équipement à hautes performances, qui mérite enfin le terme de microsonde qui lui est généralement appliqué. Les possibilités d'analyse qualitative ont été démontrées par l'étude d'échantillons constitués de silicium, d'oxyde de silicium et de nitrure de silicium. Pour chacun d'eux, des spectres de masse caractéristiques ont été établi et permettent maintenant l'identification rapide et sans aucune ambiguïté de ces 3 matrices par microsonde lamma 1000. Les possibilités d'analyse semi-quantitative, par microsondes lamma 500 et lamma 1000, ont été démontrées par le dosage du bore et de l'arsenic dans le silicium ainsi que par le dosage du bore et du phosphore dans l'oxyde de silicium. Les limites de détection ont été estimées dans une matrice de silicium à environ 50 pppm (en poids) pour le bore et à environ 600 ppm (en poids) pour l'arsenic. Cette estimation a été rendue possible par le développement d'une méthode, unique en son genre, permettant l'estimation du volume de matière sublimée (de l'ordre de quelques m#3 seulement!) Par la détermination précise (à 0,1 m près) de la profondeur des impacts laser
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Davion, Benjamin. "Synthèse et caractérisation de réseaux semi-interpénétrés de polymères à base de polyisobutène linéaire." Thesis, Cergy-Pontoise, 2010. http://www.theses.fr/2010CERG0542.
Full textAbstract:
De nouveaux matériaux à base de polyisobutène (PIB) linéaire non fonctionnel ont été élaborés dans l'objectif d'élargir les domaines d'application des polyisobutènes de masses molaires intermédiaires (10 000 < Mn < 100 000 g.mol-1), actuellement peu exploités.Une architecture de type réseau semi-interpénétré de polymères (semi-RIP) a été choisie pour immobiliser physiquement le PIB linéaire au sein de divers réseaux polyméthacrylate. Les précurseurs (monomère, réticulant et amorceur) des réseaux solubilisant le PIB, les synthèses sont réalisées sans solvant et le programme thermique a été optimisé. Des semi-RIPs homogènes macroscopiquement et ne fluant pas sont obtenus pour des proportions massiques de PIB comprises entre 20 et 70%. Les analyses thermomécaniques ont montré que ces semi-RIPs présentent une morphologie de phases co-continues. La modification de la nature et de la composition du co-réseau partenaire permet de moduler « à façon » les propriétés mécaniques (module de conservation et facteur de perte) de ces semi-RIPs entre -10 et 200°C tout en conservant certaines propriétés du PIB (imperméabilité aux gaz).Enfin, une relaxation mécanique haute température intervenant au-delà des Tgs des deux polymères associés a été détectée dans la plupart des semi-RIPs PIB/polyméthacrylate étudiés. Une interprétation de l'origine de cette relaxation mécanique a été proposéeNew linear and non functional polyisobutene (PIB) based materials have been synthesized to enlarge the potential application of medium molecular weight polyisobutènes (10 000 < Mn < 100 000 g.mol-1), currently underemployed.A semi-interpenetrating polymer network (semi-IPN) architecture have been employed to immobilize the linear PIB chains physically inside different polymethacrylate networks. The networks precursors (monomer, cross-linker and initiator) are miscible with PIB and syntheses without solvent have been carried out, and thermal curing has been optimized. Macroscopically homogeneous semi-IPNs showing no creep, for PIB weight proportions from 20 to 70%, have been obtained. Thermomechanical analyses of semi-IPNs shown co-continuous phase morphology. By changing the nature and composition of the partner co-network, the mechanical properties (storage modulus and damping factor) of the semi-IPNs are tunable between -10 and 200°C, while some properties of the PIB (very low permeation to gases) are kept.Finally, the semi-IPN architecture and the chosen synthesis pathway, among other things, lead to the observation of a high temperature relaxation above the Tg of both associated polymers, in almost all of the studied semi-IPNs. An interpretation of the origin of this phenomenon has been proposed
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Taravella, Brandon. "A Hybrid Method for Predicting Lift and Drag of Semi-planing/Semi-displacement Hull Forms." ScholarWorks@UNO, 2009. http://scholarworks.uno.edu/td/987.
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With the ever present desire for ships and boats to run faster while carrying a greater load, a need exists to reduce the drag while simultaneously increasing hydrodynamic lift. Therefore, a need for semi-planing/semi-displacement hullforms exists for vessels to carry relatively high loads (between 500 and 3000 tons) with a general length Froude number range between 0.4 and 1.0. A hybrid method for calculating the lift and drag of semi-planing/semi-displacement hull forms is developed. This is done by separating the kinematic boundary condition into odd and even parts. The odd and even parts of the kinematic boundary condition are solved independently along with the free-surface boundary condition and superimposed for a complete "hybrid" solution. The superimposed solution components relate to Michell's (1898) "thin ship" integral for odd flow and Maruo's (1967) "flat ship" integral for even flow. A generalized form of Michell's (1898) integral is provided for high speed slender bodies by implementing a more realistic near field condition (Ogilvie, 1975) and a wake trench (Vorus, 2009). A generalized form of Maruo's (1967) integral has also been developed. Comparisons of the generalized methods have been made with available model test and/or analytical data. With this, the concept of the Semihull (Vorus, 2005) is revisited. Some results are given concerning the validity of the Semihull as compared to a traditional displacement ship. Hull form optimization is also explored and the deadrise angle distribution proves to be a major factor in calm water hydrodynamic performance.
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Park, Ashley Yuuki. "Semi-rigid joints to tubular columns and their use in semi-continuous frame design." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/semirigid-joints-to-tubular-columns-and-their-use-in-semicontinuous-frame-design(5214b6d8-7df6-4197-bbcd-d4d92b8330df).html.
Full textAbstract:
Traditionally, joints are assumed to be either pinned or fully rigid, but in reality, many behave between these two extremes giving them a semi-rigid classification. By acknowledging the semi-rigidity of nominal pin joints, steel frames can be designed as semi-continuous in which the beam bending moments are partially transmitted to the column members and the need for lateral bracing is eliminated, thus reducing material and construction costs. This thesis presents the results of numerical and theoretical studies of the behaviour of bolted endplate connections to Rectangular Hollow Section (RHS) columns using flowdrill bolts and their applications in semi-continuous frame design. Such connections exhibit significant levels of initial stiffness, strength, and deformation capacity while being more cost-effective than fully welded connections. Despite this, there is limited theoretical work carried out that allows such connections to be designed using analytical methods. In addition, there are no standardised connection design tables like that for open section columns (SCI, 1995), thereby inhibiting their adoption in practice. In this thesis, newly derived equations for initial stiffness that have a greatly improved range of validity and accuracy over existing equations are presented. Equations for bending strength of a newly derived elliptical mechanism based on yield line theory and for membrane action based on internal work principles are given. Equations for flowdrill thread stripping due to gross deformation of the RHS face are also presented thus allowing prediction of all common RHS face failure mechanisms. Equations for deformation capacity are derived thus making it possible to predict the full load-deflection behaviour of the RHS face in tension component. When combined with existing equations for bolt and endplate components, it is possible to predict the full moment-rotation behaviour of bolted endplate connections to RHS columns. Extensive parametric studies using finite element analysis (FEA) as well as validation against existing tests show that the newly derived equations can accurately predict the component-level and whole joint behaviour for a wide range of configurations. Taking advantage of the initial stiffness properties that these connections offer, a parametric study is conducted to show that connections with relatively simple detailing can offer sufficient initial stiffness and strength to enable unbraced semi-continuous design of low-rise steel frames. A hand calculation method for SLS sway in semi-continuous frames is also presented thus allowing the designer to readily carry out scheme designs without advanced software knowledge. A systematic method for the detailing of these connections for use in unbraced frame design is presented to facilitate adoption in practice.
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Amalou, Zhor. "Contribution à l'étude de la structure semi-cristalline des polymères à chaînes semi-rigides." Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210832.
Full textAbstract:
Les polymères semi-cristallins à chaînes semi-rigides, bien qu’abondamment utilisés dans la vie quotidienne, représentent des systèmes complexes qui ne sont pas encore parfaitement compris. Parmi les nombreux domaines de recherche sur cette famille de polymères, l’étude de la morphologie semi-cristalline et des processus de cristallisation et de fusion de ceux-ci restent des sujets très importants. L’investigation de la morphologie semi-cristalline est rendue difficile car elle présente une structure hiérarchique composée de plusieurs niveaux d’organisation, dont le plus petit est observable à une échelle très réduite de quelques nanomètres. De plus, les aspects liés à la cinétique des processus de cristallisation et de fusion n’ont pas toujours permis de bien les mettre en évidences, les rendant ainsi par très bien compris. Cependant, les nouvelles avancées technologiques dans le domaine de la physique expérimentales ont beaucoup profité à la science des polymères. Dans ce travail, une contribution originale est apportée à cette étude, et cela en combinant diverses techniques expérimentales permettant des mesures calorifiques et structurales en températures et temps réels. L’intérêt c’est porté sur les polymères linéaires aromatiques tels que le polyéthylènes teréphthalate, PET, et le polytriméthylène téréphthalate, PTT, caractérisés par une température de transition vitreuse supérieure à l’ambiante ( Tg > 50°) et une température de fusion élevée (Tm>220°C), offrant ainsi une assez large gamme de température de cristallisation (Tm-Tg). L’étude de la structure semi-cristalline du PET à l’échelle du nanomètre et de la relaxation des phases amorphes présentes dans sa structure est facilitée par l’utilisation d’un diluant amorphe tel que le polyétherimide (PEI), qui forme un mélange miscible avec le PET.
L’utilisation de microscopie de force atomique AFM à haute température a permis d’observer la cristallisation isotherme de PET en temps réel et de décrire ainsi la cristallisation secondaire comme un processus d'épaississement des piles lamellaires. De plus, l’analyse de la structure semi-cristalline du PET et du PTT, dans l’espace direct, sont en faveur d’un modèle structural homogène, où l’épaisseur lamellaire moyenne est légèrement inférieure à l’épaisseur moyenne des régions amorphes interlamellaires. Ces résultats ont permis, d’une part, d’apporter une meilleure interprétation aux données obtenues par diffusion des rayons X aux petits angles (SAXS), et d’autre part, d’ interpréter le comportement de fusion multiple caractéristique des polymères semi-cristallin à chaînes semi-rigides par le seul processus de fusion-recristallisation. Dans l’étude investiguée sur les mélanges PET/PEI et sur le PTT pur, on montre que la cinétique d’un tel processus est particulièrement rapide comparée à la cristallisation. De plus, les observations par AFM et par microscopie optique de même que les mesures SAXS en temps réel ont montré la simultanéité et la compétition existant entre la fusion des cristaux et leur réorganisation durant la chauffe. Par ailleurs, la relaxation des régions amorphes interlamellaires, souvent considérées comme rigides, a pu être mise en évidence par les mesures AFM et SAXS réalisées à haute température sur des échantillons de PET/PEI semi-cristallins.
Doctorat en sciences, Spécialisation physique
info:eu-repo/semantics/nonPublished
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Liquet, benoit. "Sélection de modèles semi-paramétriques." Phd thesis, Université Victor Segalen - Bordeaux II, 2002. http://tel.archives-ouvertes.fr/tel-00002430.
Full textAbstract:
Cette thèse développe des méthodes de sélection de modèles pour des applications en Biostatistique et plus particulièrement dans le domaine médical. Dans la première partie, nous proposons une méthode et un programme de correction du niveau de signification d'un test lorsque plusieurs codages d'une variable explicative sont essayés. Ce travail est réalisé dans le cadre d'une régression logistique et appliqué à des données sur la relation entre cholestérol et démence. La deuxième partie de la thèse est consacrée au développement d'un critère d'information général permettant de sélectionner un estimateur parmi une famille d'estimateurs semi-paramétriques. Le critère que nous proposons est basé sur l'estimation par bootstrap de l'information de Kullback-Leibler. Nous appliquons ensuite ce critère à la modélisation de l'effet de l'amiante sur le risque de mésothéliome et nous comparons cette approche à la méthode de sélection de Birgé-Massart. Enfin, la troisième partie présente un critère de sélection en présence des données incomplètes. Le critère proposé est une extension du critère developpé dans la deuxième partie. Ce critère, construit sur l'espérance de la log-vraisemblance observée, permet en particulier de sélectionner le paramètre de lissage dans l'estimation lisse de la fonction de risque et de choisir entre des modèles stratifiés et des modèles à risques proportionnels. Nous avons notamment appliqué cette méthode à la modélisation de l'effet du sexe et du niveau d'éducation sur le risque de démence.