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Pelletier, Aurore. "Fonctions des peptides smORF Tic-Tac et Sem1 dans la reproduction et le développement chez la Drosophile." Electronic Thesis or Diss., Toulouse 3, 2023. http://www.theses.fr/2023TOU30269.
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De récentes avancées technologiques ont révélé que des petits ORF (Open Reading Frame), dont la taille est inférieure à 100 codons et qui étaient jusqu'à présent considérés comme non codants à cause de leur petite taille, peuvent être traduits en des milliers de petits peptides smORF (small ORF) dans tous les organismes. Plusieurs études ont montré que des peptides smORF peuvent interagir avec des protéines canoniques et réguler leur activité. La famille des peptides smORF représente ainsi un réservoir largement inexploré de potentiels régulateurs. Un crible fonctionnel mené chez la Drosophile nous a permis d'identifier de nouveaux peptides smORF impliqués dans le développement, dont plusieurs sont issus de la traduction d'ARN polycistroniques. Mon projet de recherche de thèse a été de caractériser la fonction chez la Drosophile de 1) Tic et Tac, deux peptides smORF inconnus codés par un ARN bicistronique , et de 2) Sem1/DSS1, un peptide très conservé. La première partie de mes travaux de thèse a été d'analyser la fonction biologique de deux peptides smORF inconnus codés par un ARN bicistronique que nous avons nommé tictac. J'ai démontré que Tic et Tac sont deux peptides traduits à partir du même ARN bicistronique tictac, dont la séquence en AA et la localisation cellulaire sont différentes. In vivo, tictac est fortement exprimé dans les organes reproducteurs mâles. A la suite d'un accouplement, les changements comportementaux et physiologiques caractérisant la réponse post-accouplement de la femelle, induits par le fluide séminal, sont affectés en absence de tictac chez les mâles. Grâce à l'analyse du transcriptome sur les organes reproducteurs mâles, je montre que l'absence de tictac conduit à une dérégulation transcriptionnelle de 150 gènes, dont 10% codent pour des composants du liquide séminal, montrant que tictac régule sa composition. La délétion spécifique de tic ou de tac, montre qu'ils ont des fonctions in vivo différentes mais que tous deux sont impliqués dans la synthèse du liquide séminal. L'analyse des glandes accessoires, l'organe fonctionnel équivalent de la prostate humaine fabriquant le fluide séminal, révèle que leur maturation et que leur fonction sécrétrice sont régulées par tictac. La recherche d'homologues de Tic et de Tac indique que Tic possède un domaine peptidique présentant une homologie avec un sous-domaine de RQC1 de levure, impliquée dans le contrôle qualité des ribosomes, alors que Tac possède un domaine serglycine, connu chez l'homme pour avoir des fonctions importantes dans la sécrétion. Ainsi, les peptides smORF Tic et Tac contribueraient à la synthèse et à la sécrétion des protéines du fluide séminal. Dans un second temps, j'ai mené l'analyse moléculaire de Sem1, une protéine intrinsèquement désordonnée connue pour interagir et réguler plusieurs complexes macromoléculaires. Comme ces données ont été générées dans des modèles in cellulo et in vitro, j'ai mené l'analyse moléculaire de Sem1 pour la première fois in vivo. J'ai montré que Sem1 est essentielle car sa délétion induit une létalité au stade larvaire. De plus, son absence entraine une apoptose massive se généralisant à l'ensemble du tissu de manière non-cellulaire autonome. Pour découpler les fonctions moléculaires de Sem1 et identifier le(s) domaine(s) protéique(s) essentiels à la survie cellulaire, j'ai généré pour chaque domaine fonctionnel une forme mutée, dont j'ai induit l'expression dans un contexte déplété de Sem1. Cette analyse structure-fonction met en évidence que les deux domaines interagissant avec l'ubiquitine sont essentiels au développement. En conclusion, mes travaux de thèse mettent en lumière de nouvelles fonctions des peptides smORF dans la reproduction et la survie cellulaire, illustrant la capacité des peptides smORF à agir sur de multiples complexes macro-moléculaires et contrôler ainsi de nombreux processus physiologiquesRecent technological advances have revealed that small ORFs (Open Reading Frame), which are less than 100 codons in size and were previously considered non-coding due to their small size, can be translated into thousands of smORF (small ORF) peptides in all organisms. Several studies have shown that smORF peptides can interact with canonical proteins and regulate their activity. Thus, the smORF peptide family represents a vast unexplored reservoir of potential regulators. A functional screen carried out in Drosophila identified new smORF peptides involved in development, several of which are derived from polycistronic RNA translation. My thesis research project was to characterize the function in Drosophila of 1) Tic and Tac, two unknown smORF peptides encoded by a bicistronic RNA, and 2) Sem1/DSS1, a highly conserved peptide. The first part of my thesis was to analyze the biological function of two unknown smORF peptides encoded by a bicistronic RNA that we named tictac. I demonstrated that Tic and Tac are two peptides translated from the same bicistronic RNA tictac, but with different AA sequences and cellular localization. In vivo, tictac is highly expressed in male reproductive organs. Following mating, behavioral and physiological changes characterizing the post-mating response in female, which are mainly induced by the seminal fluid, are affected in the absence of tictac in males. Using transcriptome analysis on male reproductive organs, I show that the absence of tictac leads to transcriptional deregulation of 150 genes. Among them, 10% code for seminal fluid components, proving that tictac regulates its composition. Specific deletion of either tic or tac highlights that they have different in vivo functions, but that both are involved in seminal fluid synthesis. The analysis of accessory glands, the functional seminal fluid-producing organ equivalent to the human prostate, reveals that their maturation and secretory function are regulated by tictac. The search for homologs of Tic and Tac indicates that Tic has a peptide domain with strong homology to a subdomain of RQC1, a yeast protein involved in ribosome quality control, and Tac has a serglycin domain, known in human to have important functions in secretion. My data therefore suggests that Tic and Tac smORF peptides may contribute to the synthesis and secretion of seminal fluid proteins. In a second step, I carried out the molecular analysis of Sem1, an intrinsically disordered protein known to interact with and regulate several macromolecular complexes. As these data were only generated in cellulo and in vitro models, I carried out the molecular analysis of Sem1 for the first time in vivo. I showed that Sem1 is essential, as its deletion induces lethality at the larval stage. Moreover, its absence leads to massive apoptosis that generalizes to the whole tissue in a non-cell-autonomous manner. To uncouple the molecular functions of Sem1 and identify the protein domains essential for cell survival, I generated a mutated form of each functional domain, then induced its expression in the absence of endogenous Sem1. This structure-function analysis revealed that two domains known to interact with ubiquitin are essential for development. In conclusion, my thesis work highlights new functions of smORF peptides in reproduction and cell survival, illustrating the ability of smORF peptides to act on multiple macro-molecular complexes, thus controlling numerous physiological processes
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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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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." Thesis, View thesis, 1997. http://handle.uws.edu.au:8081/1959.7/28403.
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This collection of short stories is about being a twenty-something in the 90s, trying to get by, have a little fun and make somewhat of a mark in the process. It’s about the process of growing up, and the seemingly desperate need to hold onto all those youthful pursuits. It’s about finding out that life as an adult tries to suck the life out of you, rather than allowing you to suck the life out of it. That constant struggle, the battle of wills between attending to your needs or just satisfying your wants. This is a time for you when your needs and wants are siblings, bickering in the back of the car on a long drive up the coast. The characters in these stories are having their good time while it lasts. Avoiding the inevitable: maturity, responsibility, adulthood. And so they should. After all, these aren’t called ‘the best years of our lives’ for nothing. The stories celebrate your life as a twenty-something.
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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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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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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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Meirinho, Sofia G. "Aplicação de um sistema de multi-sensores para a detecção de gliadinas: discriminação semi-quantitativa entre alimentos com glúten e sem glúten." Master's thesis, Instituto Politécnico de Bragança, Escola Superior Agrária, 2009. http://hdl.handle.net/10198/2537.
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A doença celíaca caracteriza-se pela intolerância ou hipersensibilidade à ingestão
de prolaminas existentes no trigo, centeio, cevada e aveia. As proteínas do glúten do
trigo contêm aproximadamente 50% de prolaminas, denominadas por gliadinas. O
tratamento para a doença celíaca consiste em fazer uma dieta livre de glúten. Assim
sendo, torna-se imperativo dispor de metodologias analíticas capazes de detectar e
quantificar o teor de glúten em alimentos, especialmente em alimentos rotulados “sem
glúten”.
Neste trabalho, estudou-se a aplicabilidade de um sistema de multi-sensores (etongue),
com 36 membranas poliméricas de sensibilidade cruzada como técnica
analítica alternativa para análise qualitativa e semi-quantitativa de produtos alimentares.
O objectivo foi estabelecer uma distinção, entre alimentos “com” e “sem glúten”. A
discriminação entre os alimentos analisados baseou-se na capacidade do sistema multisensor
fornecer diferentes perfis potenciométricos consoante diferentes conteúdos de
gliadinas presentes nos alimentos, após extracção com uma solução aquosa de etanol a
70%. Os perfis de sinais do sistema de multi-sensores em conjunto com métodos
estatísticos multivariados de reconhecimento de padrões, nomeadamente a análise
discriminante, foram utilizados para diferenciar alimentos “com” e “sem glúten”. Foram
analisados quinze alimentos comercializados em Portugal e, adquiridos em
supermercados: 8 alimentos cujo rótulo indicava a presença de glúten e 7 alimentos,
com indicação no rótulo de ausência de glúten. O teor de gliadinas nos alimentos
estudados foi confirmado por cromatografia líquida de alta resolução, após a sua
extracção. O sistema de multi-sensores utilizado, apresentou um desempenho
satisfatório na diferenciação de extractos com diferentes teores de gliadinas, permitindo
discriminar alimentos “com” e “sem glúten” com sensibilidade e especificidades globais
superiores a 95% nos dados originais e de 75% no processo de validação cruzada. Além
disso permitiu classificar de forma semi-quantitativa um alimento em 3 grupos:
alimento sem glúten (<10 ppm), alimento com teor de glúten (20-40 ppm) e alimento
com teor de glúten (100-400 ppm). Nesta discriminação obteve-se sensibilidades e
especificidades globais de 100% e superiores a 79% para os dados originais e
procedimento de validação cruzada (predição), respectivamente. Celiac disease is characterized by intolerance or hypersensitivity to ingested
prolamins, which are composites of wheat, rye, barley and oats. Gluten proteins of
wheat are constituted of approximately 50% of prolamins named gliadins. The
treatment for celiac disease is gluten - free diet.
A multisensor potentiometric (e-tongue) with 36 cross-sensibility polymeric
membranes was applied for qualitative foodstuffs analysis. The objective was to
distinguish gluten-containing from gluten-free foods. The discrimination was based on
the capability of the e-tongue device to detect different gliadins contents. The e-tongue
signal profiles were used together with supervised multivariate statistical methods for
pattern recognition. A set of 15 Portuguese foods (7 foods samples with gluten-free
indicating and 8, indicating gluten-containing), purchased in commercial supermarkets
were analyzed. The multisensor systems used, showed satisfactory performance in the
differentiation of extracts with different levels of gliadins, allowing discriminating food
"with gluten" and "gluten free" with an overall sensitivity and specificity higher than
95% in the original data and 75% for the cross-validation procedure. Moreover it
allowed to semi-quantitatively classify food samples into 3 groups: gluten-free food
(<10 ppm), gluten-containing foods (20-40 ppm) and gluten-containing food (100-400
ppm). This discrimination was achieved with an overall sensitivity and specificity of
100% and greater than 79% for the original data and cross-validation (prediction)
procedure, respectively. The satisfactory results obtained showed that the multisensor
potentiometric device developed based on lipo-polymeric membranes can be used as an
effective tool in the preliminary detection of gluten in foods.
Os resultados satisfatórios obtidos mostraram que o sistema potenciomérico de
multi-sensores desenvolvido com base em membranas lipo-poliméricas pode ser
utilizado como uma ferramenta na detecção preliminar de glúten em alimentos.
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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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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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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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Bortolato, Ettore <1976>. "Semi di paesaggio." Master's Degree Thesis, Università Ca' Foscari Venezia, 2019. http://hdl.handle.net/10579/14567.
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La ricerca verte sulle modalità di ritorno all'agricoltura e sulle motivazioni che stanno alla base di questo tipo di esigenza. Attraverso alcuni casi esemplari ho cercato di capire in che modo nascano nuove reti sociali e che ruolo abbiano nella costruzione di un nuovo immaginario ambientale.
La tesi inizia con l'analisi del paesaggio e modificazioni che questo ha subito dal secondo dopoguerra ad oggi. Sia a livello nazionale ma focalizzando l'attenzione su quello che è successo in Veneto. Cerco di indagarne le motivazioni economiche e sociali e soprattutto di capire come in questi ultimi decenni queste trasformazioni siano state accettate. L'utilizzo del concetto di terzo paesaggio è stato importante per introdurre l'idea che attualmente siamo in una fase in cui un parte del nostro territorio è costituita da zone antropizzate oramai abbandonate.
L'idea del recupero di queste aree mi ha portato ad analizzare come e da chi siano state avanzate queste istanze: ho portato due casi di studio su cui ho concentrato la ricerca sul campo e ho cercato di evidenziare in che modo si sia strutturata la rete che ha portato al recupero dei terrazzamenti di Valstagna e alla costituzione degli orti urbani di Padova.
Mi sono infine concentrato sul tema dei semi che è fondamentale sia dal punto di vista simbolico che da quello estremamente concreto della tutela dei prodotti agricoli tipici e oramai quasi dimenticati.
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COSTA, Silvana Nunes da. "Avaliação da qualidade de mistura de águas de salinidades diferentes com e sem dessalinização solar para a Região do Semi-Árido da Paraíba." Universidade Federal de Campina Grande, 1992. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/2155.
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SILVANA NUNES DA COSTA - DISSERTAÇÃO PPGECA 1992..pdf: 17415948 bytes, checksum: cbc9fe9ab0e76268ae3458f2074e4013 (MD5)Made available in DSpace on 2018-11-08T23:51:54Z (GMT). No. of bitstreams: 1 SILVANA NUNES DA COSTA - DISSERTAÇÃO PPGECA 1992..pdf: 17415948 bytes, checksum: cbc9fe9ab0e76268ae3458f2074e4013 (MD5) Previous issue date: 1992-08-27
Na região do Semi-Arido do Estado da Paraíba, a maioria dos mananciais superficiais e subterrâneos não somente tem pequena caudabilidade como também apresentam elevado teor de salinidade (cloreto - C1 - > 800 mg/1). Tais águas de alta salinidade e alta força iônica são impróprias para o consumo humano e/ou para outras finalidades. como tentativa para contornar esta situação, este trabalho mostra um estudo aprofundado de qualidade de águas de mistura em termos de grau de salinidade e de grau de saturação. A partir da utilização de águas sintéticas de alta e de baixa salinidade e de um desalinizador solar, em escala reduzida, tipo convencional, foram analisados os seguintes tipos de misturas: (I) tipo MD ou de água de alta salinidade com água dessalinizada e (II) tipo MB ou de água de alta salinidade com água de baixa salinidade. As águas sintéticas de alta salinidade foram preparadas com composição química similar àquelas da região do Semi-Árido Paraibano, e foi inserida uma espécie carbônica para simular águas naturais. Dois sistemas foram utilizados: a saber: (I) MaHCO3 + MaC1 + CaSO42H20 + H0O e (II) MaHCO3 + MaC1 + MgC12 + H0O. A variação do grau de salinidade foi feita a partir do teor de cloreto, ou seja: de 1.500 mg/1 a 3000 mg/1 para as águas de alta salinidade do sistema I, de 1000 mg/1 a 3500 mg/1 para as do sistema II e, finalmente, de 100 mg/1 a 200 mg/1 para as de baixa salinidade dos dois sistemas. Todas as simulações das águas e as determinações experimentais foram feitas no Laboratório de qualidade de Água da Companhia de Água e Esgotos da Paraíba - CAGEPA no alto Branco, Campina Grande, PB. Os resultados experimentais mostraram que ambos os processos de mistura são eficientes para a redução da salinidade das águas naturais e produzem um maior volume de água. A teoria do sistema carbonatado de Loewnthal & Marais (1976 e 1986) foi aplicada para verificação do grau de saturação das águas (potencial de precipitação/dissolução de carbonato de cálcio - CaCO3). Os resultados mostraram que as águas finais de ambas os tipos de misturas, apesar de leve tendência a subsaturação são praticamente estáveis.
In the Semi-Arid region of Paraiba State the majority of the superficial waters and groundwaters not only has a small yield hut also shows a high salinity concentration (chloride - CI- > 800 mg/1). Such waters of high salinity and high ionic strength are inadequate for human use and/or for other uses. In order to help to minimize this problem, this work shows a deep study on the quality of blended waters concerning its salinity and saturation degree. From the preparation of synthetic high salinity waters and low salinity waters and with the aid of a solar distiller, built in reduced scale and of the conventional type, it were analized the following types of blend, (i) blend MB or high salinity water with dessalinized water and (ii) blend MB or high salinity water with Lou salinity water. The synthetic high salinity waters were prepared with chemical composition similar to those of the Semi-Arid region of Paraiba and it was included a carbonic species in order to simulate a natural water. Two types of waters were used, i.e.: (I> MaHC03 + MaCl + CaSGU2HK0 and (II) MaHC03 i MaCl f MgC'ls: + CaCla + H3O. The degree of salinity was prepared from the chloride - Cl~ concentration; i.e.; from C1 - (mg/1) 1500 to 3000 for high 'salinity waters of the system I, from C1 - (mg/1) 1000 to 3500 for those of the system II and finally, from Cl~ (mg/1) 100 to 200 for low salinity waters. All simulations of the waters - and experimental determinations were made at the Laboratório of Water Quality of the Water and Wastewater Agency of Paraiba CAGEPA, in Alto Branco township, Campina Grande, PB. The experimental results indicate that both blending processes are efficient for minimizing the salinity of natural waters and produce a greater water volume. The theory of the carbonated system of Loewenthal & Marais (1976 and 1986) was applied to evaluate the saturation degree of the waters (potencial of precipitation/dissolution of calcium carbonate - CaCDs). The results showed that the final waters of both blending types although showing a slight subsaturation tendence, are practically stable.
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Rocha, César Antonio Alves da. "Filosofia sem espelhos, ética sem princípios." reponame:Repositório Institucional da UFPR, 2013. http://hdl.handle.net/1884/31789.
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Resumo: Por muito tempo a filosofia e a ciência foram vistas como atividades cuja função central era espelhar a realidade. Desse ponto de vista, diferentemente de outros discursos, como as artes e a religião, o empreendimento científico-filosófico é concebido como discurso privilegiado, por supostamente ser o único capaz de atravessar as aparências e acessar a profunda essência dos fenômenos. Não obstante, tal perspectiva vêm sofrendo severas críticas advindas da vertente pós-positivista da filosofia da ciência. Richard Rorty foi um dos autores que atacou o problema da natureza especular do conhecimento, utilizando-se, para isso, de estratégias pragmatistas, como a dissolução de pseudodicotomias, a exemplo de "realidade vs. aparência". Num mundo "sem essências ou substâncias", afirma Rorty, ciência, religião e arte não são meio de acesso à realidade, mas simplesmente instrumentos para a satisfação de desejos humanos. Apesar de ter iniciado com preocupações epistemológicas, a obra de Rorty percorreu campos filosóficos diversos, e suas reflexões pragmatistas sobre ética e política são seminais à filosofia contemporânea. E como é sabido por muitos adeptos do Behaviorismo Radical, a afinidade dessa filosofia com o Pragmatismo é constantemente reiterada, tendo sido ratificada inclusive por B. F. Skinner. Geralmente os paralelos entre as duas perspectivas são estabelecidos em nível estritamente epistemológico, mas o que dizer em relação à ética? Uma ética behaviorista radical encontra salvaguarda no Pragmatismo? Questões anteriores precisam ser enfrentadas: é possível uma ética no Behaviorismo Radical? "Ética pragmatista" não é sinônimo de caos moral? Essas são indagações que guiaram o presente trabalho. Baseando-se principalmente nas obras de Richard Rorty e B. F. Skinner, sondamos respostas possíveis. Argumentamos contra o autoritarismo derivado da aliança com premissas injustificáveis como o representacionalismo, e a favor de uma ética sem absoluto e da radicalização do pluralismo pragmatista. Apesar de eventuais divergências, as éticas pragmatista e behaviorista radical têm muito em comum, e o diálogo entre ambas pode iluminar as esperanças de produzir um mundo melhor.
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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/.
Full textAbstract:
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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Bachelder, Laura Govoni 1971. "Semi-finished modular cells." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/63220.
Full textAbstract:
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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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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Luque, Rodrigo Gheller. "Árvores BSP semi-ajustáveis." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2005. http://hdl.handle.net/10183/17349.
Full textAbstract:
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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Wacrenier, Pierre-André. "Semi-commutations et reconnaissabilité." Lille 1, 1993. http://www.theses.fr/1993LIL10018.
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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.
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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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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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Stride, Christopher B. "Semi-parametric density estimation." Thesis, University of Warwick, 1995. http://wrap.warwick.ac.uk/109619/.
Full textAbstract:
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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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. "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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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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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.
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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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Rigatti, André. "Sem título." Universidade do Estado de Santa Catarina, 2012. http://tede.udesc.br/handle/handle/679.
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Previous issue date: 2012-09-02Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This dissertation consists of a reflection on my process of creation, from some early artworks and exhibitions I have done, taking as a basis the question of the study of space as a common thread of the whole process. The identification of groups of artworks presented here is intended to bring them as a process, set, relation and projection of a subjective desire. To this end, the analysis rests on the concepts of the research process in contemporary art as a proposal for reading and organizing this process. It mentions the dynamics of spatial structure and its consequent transformation present in the thought of Michel de Certeau, and the notion of site as a context in training proposed by Miwon Kwon. Divided into three parts or chapters, I present to start with the first series of my process, and the two subsequent parts of some developments that are linked to the relational proposal and different ways of look¬ing at an artistic operation as a context that incorporates and relates proposition, physical space and the viewer
Esta dissertação consiste em uma reflexão sobre o meu processo de criação, a partir de alguns primeiros trabalhos e exposições que realizei, fundamentando-se na questão do estudo do espaço como fio condutor de todo o processo. A identificação de conjuntos de trabalhos presentes neste estudo tem o propósito de trazê-los como processo, jogo, relação subjetiva e projeção de um desejo. Para tanto, a análise apóia-se nas concepções da linha de pesquisa em processos artísticos contemporâneos como proposta de leitura e organização deste processo. Traz referência às dinâmicas de estruturação espacial e sua consequente transformação presentes no pensamento de Michel de Certeau, bem como da noção do site como um contexto em formação proposto por Miwon Kwon. Distribuídos em três partes ou capítulos, apresento de início as primeiras séries de meu processo, e nas duas partes subsequentes alguns desdobramentos que vinculam-se à propostas relacionais e modos possíveis de se encarar uma operação artística como um contexto que incorpora e relaciona, proposição, espaço físico e espectador
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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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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.
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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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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.
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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.