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We give a strongly polynomial time combinatorial algorithm to minimise the largest eigenvalue of the weighted Laplacian of a bipartite graph. This is accomplished by solving the dual graph embedding problem which arises from a semidefinite programming formulation. In particular, the problem for trees can be solved in time cubic in the number of vertices.

Structural algorithms incorporate the interdependence of outputs into the prediction, the loss, or both. Frank-Wolfe optimizations of pairwise losses and Gaussian conditional random fields for multivariate output regression are two such structural algorithms. Pairwise losses are standard 0-1 classification surrogate losses applied to pairs of features and outputs, resulting in improved ranking performance (area under the ROC curve, average precision, and F-1 score) at the cost of increased learning complexity. In this dissertation, it is proven that the balanced loss 0-1 SVM and the pairwise SVM have the same dual loss and the pairwise dual coefficient domain is a subdomain of the balanced loss 0-1 SVM with bias dual coefficient domain. This provides a theoretical advancement in the understanding of pairwise loss, which we exploit for the development of a novel ranking algorithm that is fast and memory efficient method with state the art ranking metric performance across eight benchmark data sets. Various practical advancements are also made in multivariate output regression. The learning time for Gaussian conditional random fields is greatly reduced and the parameter domain is expanded to enable repulsion between outputs. Last, a novel multivariate regression is presented that keeps the desirable elements of GCRF and infuses them into a local regression model that improves mean squared error and reduces learning complexity. / Computer and Information Science

Recommendation systems are information filtering systems that help users effectively and efficiently explore large amount of information and identify items of interest. Accurate predictions of users' interests improve user satisfaction and are beneficial to business or service providers. Researchers have been making tremendous efforts to improve the accuracy of recommendations. Emerging trends of technologies and application scenarios, however, lead to challenges other than accuracy for recommendation systems. Three new challenges include: (1) opinion spam results in untrustworthy content and makes recommendations deceptive; (2) users prefer diversified content; (3) in some applications user behavior data may not be available to infer users' preference. This thesis tackles the above challenges. We identify features of untrustworthy commercial campaigns on a question and answer website, and adopt machine learning-based techniques to implement an adaptive detection system which automatically detects commercial campaigns. We incorporate diversity requirements into a classic theoretical model and develop efficient algorithms with performance guarantees. We propose a novel and robust approach to infer user preference profile from recommendations using copula models. The proposed approach can offer in-depth business intelligence for physical stores that depend on Wi-Fi hotspots for mobile advertisement. / Graduate / 0984 / cchenv@uvic.ca

Made available in DSpace on 2016-03-15T19:34:23Z (GMT). No. of bitstreams: 1 Rodrigo Guedes Casali.pdf: 50227586 bytes, checksum: 737e1069d703888bd9e4cc046ac94f81 (MD5) Previous issue date: 2015-02-13 / The work aims to study the collective bargaining labour institute, with the presenting of his concept for both the homeland doctrine as to the ILO, its specific principles, its relation to the principle of freedom of association, the regulatory instruments (agreement and collective bargaining agreement), scope, finally, its main aspects. Study will be, even if it is possible federal civil servants carry out collective bargaining work, as they are submitted to a constitutional pay system requiring budgetary provision for the creation of job or change in salary is preceded by legal provision, and as that that law should be a private initiative of the Chief Executive (Article 167, item II, Article 61, paragraph 1, item II, point a, Article 169, paragraph 1, Article 37, item X, all of the Constitution) . Presents other arguments that prevent collective bargaining in the federal public service, for example, the absence of item XXVI of Article 7 of the Constitution in the list of social rights of civil servants contained in paragraph 3 of Article 39 also of the Constitution; the decision of the Supreme Court handed down in the records of direct action of unconstitutionality No. 492-1 / 1990, which was the origin of the subtraction of paragraph d of Article 240 of Law No. 8,112 / 1990, which provided for collective bargaining as a right of server, but it was revoked. It also presents some arguments conducive to the realization of collective bargaining in the federal public service, as the entry into force of the Convention in our legal system No. 151 of the ILO, 1978 and the forecast of the right to free union association and union strike to the servers, so, how can design the right to strike without providing for the right to collective bargaining? Finally, it is practical aspects of the implementation of the negotiation that takes place today between federal public servants and the Union (Direct and Indirect Administration). / O trabalho tem por objetivo estudar o instituto da negociação coletiva de trabalho com a apresentação de seu conceito tanto para a doutrina pátria quanto para a OIT, seus princípios específicos, sua relação com o princípio da liberdade sindical, os instrumentos normativos (acordo e convenção coletiva de trabalho), abrangência, enfim, seus principais aspectos. Estudar-se-á, ainda, se é possível os servidores públicos federais realizarem negociação coletiva de trabalho, pois estão submetidos a um sistema constitucional de remuneração que exige previsão orçamentária para a criação de cargo ou alteração no vencimento que seja precedida de previsão legal, bem como que referida lei deve ser de iniciativa privativa do Chefe do Poder Executivo (artigo 167, inciso II; artigo 61, §1ş, inciso II, alínea a; artigo 169, §1ş; artigo 37, inciso X, todos da Constituição). Apresentam-se outros argumentos que impedem a negociação coletiva de trabalho no serviço público federal, como, por exemplo, a ausência do inciso XXVI, do artigo 7ş, da Constituição no rol de direitos sociais dos servidores públicos contido no §3ş, do artigo 39, também da Constituição; a decisão do Supremo Tribunal Federal proferida nos autos da Ação Direta de Inconstitucionalidade nº 492-1/1990, que foi a origem da subtração da alínea d, do artigo 240, da Lei nº 8.112/1990, que previa a negociação coletiva como direito do servidor, mas foi revogada. Também se apresentam alguns argumentos favoráveis à realização da negociação coletiva no serviço público federal, como a entrada em vigor em nosso ordenamento jurídico da Convenção nº 151 da OIT, de 1978 e a previsão dos direitos à livre associação sindical e realização de greve aos servidores, assim, como é possível conceber o direito de greve sem prever o direito à negociação coletiva? Por fim, trata-se de aspectos práticos da realização da negociação que acontece hoje entre servidores públicos federais e a União (Administração Direta e Indireta).

Thèse en cotutelle avec l'Université de Strasbourg. / Le vieillissement de la population nous amène à imaginer de nouvelles approches pour promouvoir la santé et le bien-être à un âge avancé. Les liens sociaux et la mobilité quotidienne jouent potentiellement un rôle important, mais ces dynamiques sont actuellement mal comprises. Cette thèse vise à explorer comment les réseaux sociaux des aînés s'intègrent dans leurs espaces d'activité, et comment les relations sociales, inscrites dans l'environnement spatial, sont associées au bien-être. La thèse explore les données de l’étude CURHA collectées au Québec au sein de la cohorte NuAge. La population d’étude comprend 183 aînés âgés de 79 ans et plus enquêtés en 2014 et 2015, habitant dans les régions de Montréal et Sherbrooke. Le premier volet de cette thèse est de nature méthodologique, et concerne le développement d’un module de questionnaire cartographique interactif permettant de recueillir à la fois des lieux d’activité réguliers et des relations sociales, ces deux niveaux d'information connectés en fonction des “personnes vues dans les lieux d’activités”. Ces données ont été représentées en réseaux bipartites, ce qui a permis de distinguer des structures en étoile formées d’un nœud central connecté à un ensemble de nœuds périphériques. Ces structures identifient d’une part un lieu où l’aîné voit plusieurs personnes, qui pour la plupart, ne sont rencontrées qu’en ce lieu, et d’autre part une personne centrale avec qui plusieurs activités sont réalisées, de manière relativement exclusive.  Le deuxième volet de la thèse porte sur les liens entre les relations sociales et le bien-être émotionnel. Les relations sociales peuvent être catégorisées en relations proches, personnelles, ou de camaraderie. Le nombre de camarades et la présence d’une relation proche sont positivement associés au niveau de bien-être émotionnel, tandis que le nombre de relations personnelles est associé négativement au bien-être émotionnel.  Le dernier volet décrit de manière plus détaillée la distribution des catégories de relations sociales au sein des structures en étoiles identifiées dans les réseaux bipartites. Les relations proches représentent la majorité des personnes qui sont rencontrées ou qui accompagnent les personnes âgées dans un grand nombre de lieux d’activités. La résidence primaire est un lieu de socialisation importante, tandis que les lieux non résidentiels semblent servir de cadre privilégié aux relations de groupes. Les relations personnelles sont plus fréquentes au domicile des participants que dans les autres lieux d'activités. Cette thèse montre que l'analyse de réseau offre un cadre utile pour étudier les relations sociales en rapport avec l'environnement géospatial. Elle met en lumière la concentration de la vie sociale des aînés dans un nombre restreint de lieux d’activités, ainsi que la distribution spatiale différentielle de catégories de relations sociales spécifiquement associée au bien-être émotionnel. Ces approches peuvent soutenir la compréhension des influences socio-environnementales et favoriser la santé et le bien-être des aînés. / The aging of the population leads us to imagine new approaches to promote health and well-being in old age. Social connections and daily mobility potentially play an important role, but these dynamics are currently poorly understood. This thesis aims to explore how older adults' social networks fit into their activity spaces, and how social relationships, embedded in the spatial environment, are associated with well-being. The thesis explores data from the Contrasted Urban settings for Healthy Aging (CURHA) study collected in Quebec within the NuAge cohort. The study population includes 183 older adults aged 79 years and older surveyed in 2014 and 2015, living in the Montréal and Sherbrooke regions. The first part of this thesis is methodological, and concerns the development of an interactive cartographic questionnaire module allowing to collect both regular activity locations and social relationships, those two layers of information connected by “people seen at activity locations”. These data were represented as bipartite networks, which allowed us to identify star-like structures formed by a central node connected to a set of peripheral nodes. These structures identify, on the one hand, a location where the older adult sees several people, most of whom he or she meets only in that place, and on the other hand, a central person with whom several activities are carried out, while being the only person seen in most of these locations. The second part of the thesis focuses on the links between social relationships and emotional well-being. Social relationships can be categorized into close relationships, personal relationships, or companionship. The number of companions and the presence of a close relationship are positively associated with emotional well-being, while the number of personal relationships is negatively associated with emotional well-being.  The final section describes in more detail the distribution of social relationship categories within the star-like structures identified within the bipartite networks. Close relations represent the majority of people who are met or accompany the elderly in a large number of activity locations. The primary residence is an important place of socialization, while non-residential places seem to serve as a privileged setting for group relations. Personal relationships are most common in participants' homes. This thesis shows that network analysis provides a useful framework for studying social relationships within the geospatial environment. It highlights the concentration of older adults' social lives in a limited number of activity locations, as well as the differential spatial distribution of social relationship categories specifically associated with emotional well-being. These approaches can help to understand the socio-environmental influences on older adults' health and well-being.

Let Ω be the Fraïssé limit of a class of relational structures. We seek to answer the following semigroup theoretic question about Ω. What are the group H-classes, i.e. the maximal subgroups, of End(Ω)? Fraïssé limits for which we answer this question include the random graph R, the random directed graph D, the random tournament T, the random bipartite graph B, Henson's graphs G[subscript n] (for n greater or equal to 3) and the total order Q. The maximal subgroups of End(Ω) are closely connected to the automorphism groups of the relational structures induced by the images of idempotents from End(Ω). It has been shown that the relational structure induced by the image of an idempotent from End(Ω) is algebraically closed. Accordingly, we investigate which groups can be realised as the automorphism group of an algebraically closed relational structure in order to determine the maximal subgroups of End(Ω) in each case. In particular, we show that if Γ is a countable graph and Ω = R,D,B, then there exist 2[superscript aleph-naught] maximal subgroups of End(Ω) which are isomorphic to Aut(Γ). Additionally, we provide a complete description of the subsets of Q which are the image of an idempotent from End(Q). We call these subsets retracts of Q and show that if Ω is a total order and f is an embedding of Ω into Q such that im f is a retract of Q, then there exist 2[superscript aleph-naught] maximal subgroups of End(Q) isomorphic to Aut(Ω). We also show that any countable maximal subgroup of End(Q) must be isomorphic to Zⁿ for some natural number n. As a consequence of the methods developed, we are also able to show that when Ω = R,D,B,Q there exist 2[superscript aleph-naught] regular D-classes of End(Ω) and when Ω = R,D,B there exist 2[superscript aleph-naught] J-classes of End(Ω). Additionally we show that if Ω = R,D then all regular D-classes contain 2[superscript aleph-naught] group H-classes. On the other hand, we show that when Ω = B,Q there exist regular D-classes which contain countably many group H-classes.

Der Zellzyklus organisiert die Zellteilung, und kontrolliert die Replikation der DNA sowie die Weitergabe des Genoms an die nächste Zellgeneration. Er unterliegt einer strengen Kontrolle auf molekularer Ebene. Diese molekularen Kontrollmechanismen sind für das Überleben eines Organismus essentiell, da Fehler Krankheiten begüngstigen können. Vor allem Krebs ist assoziiert mit Abweichungen im Ablauf des Zellzyklus. Die Aufklärung solcher Kontrollmechanismen auf molekularer Ebene ermöglicht einerseits das Verständnis deren grundlegender Funktionsweise, andererseits können solche Erkenntnisse dazu beitragen, Methoden zu entwickeln um den Zellzyklus steuern zu können. Um die molekularen Abläufe des Zellzyklus in ihrer Gesamtheit besser zu verstehen, eignen sich computergestützte Analysen. Beim Zellzyklus handelt es sich um einen Signaltransduktionsweg. Die Eigenschaften dieser Prozesse stellen Rekonstruktion und Übersetzung in digital lesbare Formate vor besondere Herausforderungen in Bezug auf Skalierbarkeit, Simulierbarkeit und Parameterschätzung. Diese Studie präsentiert eine großskalige Netzwerkrekonstruktion des Zellzyklus des Modellorganismus Saccharomyces cerevisiae. Hierfür wurde die reaction-contingency Sprache benutzt, die sowohl eine mechanistisch detaillierte Rekonstruktion auf molekularer Ebene zulässt, als auch deren Übersetzung in ein bipartites Boolesches Modell. Für das Boolesche Modell mit 2506 Knoten konnte ein zyklischer Attraktor bestimmt werden, der das Verhalten einer sich teilenden Hefezelle darstellt. Das Boolesche Modell reproduziert zudem das erwartete phänotypische Verhalten bei Aktivierung von vier Zellzyklusinhibitoren, und in 32 von 37 getesteten Mutanten. Die Rekonstruktion des Zellzyklus der Hefe kann in Folgestudien genutzt werden, um Signaltransduktionswege zu integrieren, die mit dem Zellzyklus interferieren, deren Schnittstellen aufzuzeigen, und dem Ziel, die molekularen Mechanismen einer ganzen Zelle abzubilden, näher zu kommen. Diese Studie zeigt zudem, dass eine auf reaction- contingency Sprache basierte Rekonstruktion geeignet ist, um ein biologisches Netzwerk konsistent mit empirischer Daten darzustellen, und gleichzeitig durch Simulation die Funktionalität des Netzwerkes zu überprüfen. / The survival of a species depends on the correct transmission of an intact genome from one generation to the next. The cell cycle regulates this process and its correct execution is vital for survival of a species. The cell cycle underlies a strict control mechanism ensuring accurate cell cycle progression, as aberrations in cell cycle progression are often linked to serious defects and diseases such as cancer. Understanding this regulatory machinery of the cell cycle offers insights into how life functions on a molecular level and also provides for a better understanding of diseases and possible approaches to control them. Cell cycle control is furthermore a complex mechanism and studying it holistically provides for understanding its collective properties. Computational approaches facilitate holistic cell cycle control studies. However, the properties of the cell cycle control network challenge large-scale in silico studies with respect to scalability, model execution and parameter estimation. This thesis presents a mechanistically detailed and executable large-scale reconstruction of the Saccharomyces cerevisiae cell cycle control network based on reaction- contingency language. The reconstruction accounts for 229 proteins and consists of three individual cycles corresponding to the macroscopic events of DNA replication, spindle pole body duplication, and bud emergence and growth. The reconstruction translated into a bipartite Boolean model has, using an initial state determined with a priori knowledge, a cyclic attractor which reproduces the cyclic behavior of a wildtype yeast cell. The bipartite Boolean model has 2506 nodes and correctly responds to four cell cycle arrest chemicals. Furthermore, the bipartite Boolean model was used in a mutational study where 37 mutants were tested and 32 mutants found to reproduce known phenotypes. The reconstruction of the cell cycle control network of S. cerevisiae demonstrates the power of the reaction-contingency based approach, and paves the way for network extension with regard to the cell cycle machinery itself, and several signal transduction pathways interfering with the cell cycle.

Devido a restrições de aplicabilidade presentes nos algoritmos para a solução de problemas de otimização combinatória, os sistemas baseados em redes neurais artificiais e algoritmos genéticos oferecem um método alternativo para solucionar tais problemas eficientemente. Os algoritmos genéticos devem a sua popularidade à possibilidade de percorrer espaços de busca não-lineares e extensos. Já as redes neurais artificiais possuem altas taxas de processamento por utilizarem um número elevado de elementos processadores simples com alta conectividade entre si. Complementarmente, redes neurais com conexões realimentadas fornecem um modelo computacional capaz de resolver vários tipos de problemas de otimização, os quais consistem, geralmente, da otimização de uma função objetivo que pode estar sujeita ou não a um conjunto de restrições. Esta tese apresenta uma abordagem inovadora para resolver problemas de conexão em otimização combinatória utilizando uma arquitetura neuro-genética. Mais especificamente, uma rede neural de Hopfield modificada é associada a um algoritmo genético visando garantir a convergência da rede em direção aos pontos de equilíbrio factíveis que representam as soluções para os problemas de otimização combinatória. / Due to applicability constraints involved with the algorithms for solving combinatorial optimization problems, systems based on artificial neural networks and genetic algorithms are alternative methods for solving these problems in an efficient way. The genetic algorithms must its popularity to make possible cover nonlinear and extensive search spaces. On the other hand, artificial neural networks have high processing rates due to the use of a massive number of simple processing elements and the high degree of connectivity between these elements. Additionally, neural networks with feedback connections provide a computing model capable of solving a large class of optimization problems, which refer to optimization of an objective function that can be subject to constraints. This thesis presents a novel approach for solving connection problems in combinatorial optimization using a neurogenetic approach. More specifically, a modified Hopfield neural network is associated with a genetic algorithm in order to guarantee the convergence of the network to the equilibrium points, which represent feasible solutions for the combinatorial optimization problems.

Dans cette thèse nous avons élaboré puis automatisé une chaîne complète de recherche d'image par le contenu. Ceci nous a permis de définir une "sémantique limitée" relative à la satisfaction de l'utilisateur quant à la réponse du système. Notre approche est locale c'est-à-dire basée sur les régions de l'image. La décomposition en entités visuelles permet d'exhiber des interactions entres celles-ci et du coup faciliter l'accès à un niveau d'abstraction plus élevé. Nous avons considéré plus particulièrement trois points de la chaîne : l'extraction de régions fiables, leur caractérisation puis la mesure de similarité. Nous avons mis au point une méthode de type C-moyennes floues avec double contrainte spatiale et pyramidale. La classification d'un pixel donné est contrainte à suivre le comportement de ses voisins dans le plan de l'image et de ses ancêtres dans la pyramide. Pour la caractérisation des régions deux méthodes ont été proposées basées sur les courbes de Peano. La première repose sur un principe grammatical et la deuxième manipule le spectre par l'utilisation des filtres de Gabor. La signature de l'image requête ou cible consiste en une liste d'entités visuelles. La mesure de similarité entre entités guide l'appariement. Nous avons élaboré une méthode basée sur la mise en correspondance dans les deux sens, requête vers cible et vice versa, afin de donner indépendamment une grande priorité aux éléments qui se préfèrent mutuellement. Chaque partie du système a été testée et évaluée séparément puis ramenée à l'application CBIR. Notre technique a été évaluée sur des images aériennes (et ou satellitaires). Les résultats en terme de "rappel-précision" sont satisfaisants comparé notamment aux méthodes classiques type matrice de co-occurrence des niveaux de gris et Gabor standard. Pour ouvrir sur de futures extensions et montrer la généralité de notre méthode, la conclusion explique sa transposition à la recherche de situations en conduite automobile, au prix d'une adaptation limitée des paramètres.