[pt] O uso de robôs de busca para coletar informações para um determinado contexto sempre foi um problema desafiante e tem crescido substancialmente nos últimos anos. Por exemplo, robôs de busca podem ser utilizados para capturar dados de redes sociais profissionais. Em particular, tais redes permitem estudar as trajetórias profissionais dos egressos de uma universidade, e responder diversas perguntas, como por exemplo: Quanto tempo um ex-aluno da PUC-Rio leva para chegar a um cargo de relevância? No entanto, um problema de natureza comum a este cenário é a impossibilidade de coletar informações devido a sistemas de autenticação, impedindo um robô de busca de acessar determinadas páginas e conteúdos. Esta dissertação aborda uma solução para capturar dados, que contorna o problema de autenticação e automatiza o processo de coleta de dados. A solução proposta coleta dados de perfis de usuários de uma rede social profissional para armazenamento em banco de dados e posterior análise. A dissertação contempla ainda a possibilidade de adicionar diversas outras fontes de dados dando ênfase a uma estrutura de armazém de dados. / [en] The use of search bots to collect information for a given context has grown substantially in recent years. For example, search bots may be used to capture data from professional social networks. In particular, such social networks facilitate studying the professional trajectory of the alumni of a given university, and answer several questions such as: How long does a former student of PUC-Rio take to arrive at a management position? However, a common problem in this scenario is the inability to collect information due to authentication systems, preventing a search robot from accessing certain pages and content. This dissertation addresses a solution to capture data, which circumvents the authentication problem and automates the data collection process. The proposed solution collects data from user profiles for later database storage and analysis. The dissertation also contemplates the possibility of adding several other sources of data giving emphasis to a data warehouse structure.

This thesis aims to describe and analyze the process of construction of otherness, use of humour and taste performance on Facebook page Divnolidi z Brna a okolí. Theoretical background explores contemporary approaches to the research of social network sites (particulary on privacy and sharing; a separate chapter is devoted to Facebook social network site), sociological term of taste as the instrument for social distinction (here, the study is primarily based on the work of Pierre Bourdieu), interdisciplinary concept of otherness (in which we examine works of Mary Douglas, Stuart Hall and Marc Augé) as well as theoretical approach to humour called theory of superiority. We conducted a quantitative description of Divnolidi z Brna a okolí page and a qualitative analysis (a method often called "data-crawling") of 47 page posts. Analytical section of this study focuses on answering following questions: What types of posts can be found on the site? How are individuals captured in these posts perceived? How do the users perceive taste / otherness of the captured individuals? Where were these "weird people" (in Czech language "divnolidi") spotted and how do the users perceive these places? Furthermore, we analyze the use of humour by the page users and the way they react to the site's policy and other...

Nos últimos anos a Web obteve um crescimento exponencial, se tornando o maior repositório de informações já criado pelo homem e representando uma fonte nova e relevante de informações potencialmente úteis para diversas áreas, inclusive a área nuclear. Entretanto, devido as suas características e, principalmente, devido ao seu grande volume de dados, emerge um problema desafiador relacionado à utilização das suas informações: a busca e recuperação informações relevantes e úteis. Este problema é tratado por algoritmos de busca e recuperação de informação que trabalham na Web, denominados rastreadores web. Neste trabalho é apresentada a pesquisa e desenvolvimento de um algoritmo rastreador que efetua buscas e recupera páginas na Web com conteúdo textual relacionado ao domínio nuclear e seus temas, de forma autônoma e massiva. Este algoritmo foi projetado sob o modelo de um sistema especialista, possuindo, desta forma, uma base de conhecimento que contem tópicos nucleares e palavras-chave que os definem e um mecanismo de inferência constituído por uma rede neural artificial perceptron multicamadas que efetua a estimação da relevância das páginas na Web para um determinado tópico nuclear, no decorrer do processo de busca, utilizando a base de conhecimento. Deste modo, o algoritmo é capaz de, autonomamente, buscar páginas na Web seguindo os hiperlinks que as interconectam e recuperar aquelas que são mais relevantes para o tópico nuclear selecionado, emulando a habilidade que um especialista nuclear tem de navegar na Web e verificar informações nucleares. Resultados experimentais preliminares apresentam uma precisão de recuperação de 80% para o tópico área nuclear em geral e 72% para o tópico de energia nuclear, indicando que o algoritmo proposto é efetivo e eficiente na busca e recuperação de informações relevantes para o domínio nuclear. / Over the last years the Web has obtained an exponential growth, becoming the largest information repository ever created and representing a new and valuable source of potentially useful information for several topics and also for nuclear-related themes. However, due to the Web characteristics and, mainly, because of its huge data volume, finding and retrieving relevant and useful information are non-trivial tasks. This challenge is addressed by web search and retrieval algorithms called web crawlers. This work presents the research and development of a crawler algorithm able to search and retrieve webpages with nuclear-related textual content, in autonomous and massive fashion. This algorithm was designed under the expert systems model, having, this way, a knowledge base that contains a list of nuclear topics and keywords that define them and an inference engine composed of a multi-layer perceptron artificial neural network that performs webpages relevance estimates to some knowledge base nuclear topic while searching the Web. Thus, the algorithm is able to autonomously search the Web by following the hyperlinks that interconnect the webpages and retrieving those that are more relevant to some predefined nuclear topic, emulating the ability a nuclear expert has to browse the Web and evaluate nuclear information. Preliminary experimental results show a retrieval precision of 80% for the nuclear general domain topic and 72% for the nuclear power topic, indicating that the proposed algorithm is effective and efficient to search the Web and to retrieve nuclear-related information.

This thesis explores Chance-Constrained Programming (CCP) in the context of learning. It is shown that chance-constraint approaches lead to improved algorithms for three important learning problems — classification with specified error rates, large dataset classification and Ordinal Regression (OR). Using moments of training data, the CCPs are posed as Second Order Cone Programs (SOCPs). Novel iterative algorithms for solving the resulting SOCPs are also derived. Borrowing ideas from robust optimization theory, the proposed formulations are made robust to moment estimation errors. A maximum margin classifier with specified false positive and false negative rates is derived. The key idea is to employ chance-constraints for each class which imply that the actual misclassification rates do not exceed the specified. The formulation is applied to the case of biased classification. The problems of large dataset classification and ordinal regression are addressed by deriving formulations which employ chance-constraints for clusters in training data rather than constraints for each data point. Since the number of clusters can be substantially smaller than the number of data points, the resulting formulation size and number of inequalities are very small. Hence the formulations scale well to large datasets. The scalable classification and OR formulations are extended to feature spaces and the kernelized duals turn out to be instances of SOCPs with a single cone constraint. Exploiting this speciality, fast iterative solvers which outperform generic SOCP solvers, are proposed. Compared to state-of-the-art learners, the proposed algorithms achieve a speed up as high as 10000 times, when the specialized SOCP solvers are employed. The proposed formulations involve second order moments of data and hence are susceptible to moment estimation errors. A generic way of making the formulations robust to such estimation errors is illustrated. Two novel confidence sets for moments are derived and it is shown that when either of the confidence sets are employed, the robust formulations also yield SOCPs.

Nos últimos anos a Web obteve um crescimento exponencial, se tornando o maior repositório de informações já criado pelo homem e representando uma fonte nova e relevante de informações potencialmente úteis para diversas áreas, inclusive a área nuclear. Entretanto, devido as suas características e, principalmente, devido ao seu grande volume de dados, emerge um problema desafiador relacionado à utilização das suas informações: a busca e recuperação informações relevantes e úteis. Este problema é tratado por algoritmos de busca e recuperação de informação que trabalham na Web, denominados rastreadores web. Neste trabalho é apresentada a pesquisa e desenvolvimento de um algoritmo rastreador que efetua buscas e recupera páginas na Web com conteúdo textual relacionado ao domínio nuclear e seus temas, de forma autônoma e massiva. Este algoritmo foi projetado sob o modelo de um sistema especialista, possuindo, desta forma, uma base de conhecimento que contem tópicos nucleares e palavras-chave que os definem e um mecanismo de inferência constituído por uma rede neural artificial perceptron multicamadas que efetua a estimação da relevância das páginas na Web para um determinado tópico nuclear, no decorrer do processo de busca, utilizando a base de conhecimento. Deste modo, o algoritmo é capaz de, autonomamente, buscar páginas na Web seguindo os hiperlinks que as interconectam e recuperar aquelas que são mais relevantes para o tópico nuclear selecionado, emulando a habilidade que um especialista nuclear tem de navegar na Web e verificar informações nucleares. Resultados experimentais preliminares apresentam uma precisão de recuperação de 80% para o tópico área nuclear em geral e 72% para o tópico de energia nuclear, indicando que o algoritmo proposto é efetivo e eficiente na busca e recuperação de informações relevantes para o domínio nuclear. / Over the last years the Web has obtained an exponential growth, becoming the largest information repository ever created and representing a new and valuable source of potentially useful information for several topics and also for nuclear-related themes. However, due to the Web characteristics and, mainly, because of its huge data volume, finding and retrieving relevant and useful information are non-trivial tasks. This challenge is addressed by web search and retrieval algorithms called web crawlers. This work presents the research and development of a crawler algorithm able to search and retrieve webpages with nuclear-related textual content, in autonomous and massive fashion. This algorithm was designed under the expert systems model, having, this way, a knowledge base that contains a list of nuclear topics and keywords that define them and an inference engine composed of a multi-layer perceptron artificial neural network that performs webpages relevance estimates to some knowledge base nuclear topic while searching the Web. Thus, the algorithm is able to autonomously search the Web by following the hyperlinks that interconnect the webpages and retrieving those that are more relevant to some predefined nuclear topic, emulating the ability a nuclear expert has to browse the Web and evaluate nuclear information. Preliminary experimental results show a retrieval precision of 80% for the nuclear general domain topic and 72% for the nuclear power topic, indicating that the proposed algorithm is effective and efficient to search the Web and to retrieve nuclear-related information.

This thesis has been concerned with a few problems in systems driven at the scale of particles. The problems dealt with here can be extended and elaborated upon in a variety of ways. In 2 we examine the dynamics of a fluid membrane in contact with a fluid containing active particles. In particular, we show that such a membrane generically enters a statistical steady state with wave-like dispersion. While the numerical results are satisfying, a one-step coarse-graining calculation, in line with [66,93], will, we expect, yield a pair of coupled stochastic differential equations (probably KPZ like at least in one dimension) with wave-like dispersion. This calculation in of interest from a theoretical point-of-view. Further, the numerical exploration of the full set of equations is also left for future work, but can be relevant to many biological systems. In 3 we show that an active fluid confined in an annular channel starts to rotate spontaneously. Further, we predict the existence of banded concentration profile. Such profiles have not yet been observed in experiments. Further, it will be interesting to study what happens to our conclusions if we include the effect of treadmilling in our calculation. In 4 we describe a solid driven by active particles. Specifically, we only concern ourselves with the polar elastomeric phase of the material. However, the questions regarding the transition into that phase are interesting and have not been explored. How exactly does a polarisation transition happen in an active polar elastomer? Is it the same as in an active nematic elastomer? What is the nature of the gelation transition in an active polar fluid? What is the dynamics of nematic defects in an elastomer? Can the presence of the elastomer prevent defect separation? We are at present trying to answer these questions. In 5 we examine the dynamics of an active fluid confined in a channel. It will be interesting to test the prediction about fluctuations in a confined active system, which we show will be normal, in experiments on highly confined actomyosin systems. In 6 we write down the coupled equations of a conformation tensor and the apolar order parameter. This is a generic framework for studying viscoelastic active fluids. A fuller study of the effect of increasing the cross-linker density in such system remains to be done, both theoretically and experimentally. In general, we have shown in the thesis that the understanding of active systems can provide a mechanistic explanation of various biological observations. However, at times the comparison between theory and biological experiments become complicated due to the inherently complicated nature of the experimental systems. Thus, for a more rigorous experimental test of the theory, it is necessary to construct cleaner reconstituted systems with possibly as few as three components. Efforts in this direction have recently borne fruit [129]. However, a complete theoretical understanding of the rich behaviour evinced in these systems is as yet lacking. We expect that the conformation tensor theory we developed in chapter 6 will provide an explanation for the anomalous rheological behaviour observed in these systems. Even in the theoretical front, lot of questions remain to be answered. The dry polar active system, described by the Toner-Tu equations have been shown to undergo a transition to a state with LRO. However, though mean-field theory predicts a second order transition [151, 152, 156], detailed numerical analysis suggests that it is actually first-order with pre-transitional solitonic bands. This has been recently examined by Chate et al. [26] who mapped it to a dynamical system, but a complete theory is still lacking. Apolar systems present another set of challenges. First, the concentration coupling with the order parameter should create similar pre-transitional effects at the order-disorder transition for this system also. This has been studied to a certain extent [133]. However, the more interesting question concerns the role of defects in apolar systems and whether they allow for the possibility of even QLRO in two dimensions. The +1/2 nematic defect has a polarity, and can thus move balistically [51, 108, 115, 149] in a dry system. However, the −1/2 defect has a three-fold symmetry [27] and its motion is thus purely diffusive. Now consider a pair of +1/2 and −1/2 defect pair that can form due to noise in the system (since it does not violate charge conservation). Depending on the configuration and the kind of activity, this defect pair can unbind at zero temperature. Unbound defects would imply that the order is short-ranged. However, it appears from detailed simulations of an agent based Vicsek-like model of active nematics, that there exists a QLRO nematic in two dimensions [111]! How does an active nematic escape being destroyed by defect unbinding? Does concentration have a major role to play? If so, does making the concentration a non-conserved, and thus fast, variable by, for example, including evaporation-deposition rules in the model studied by Chate et al. [28] destroy the QLRO? Also, does the hydrodynamic theory for Malthusian (i.e. one in which the concentration relaxes fast to a steady value) nematics show only short-ranged order, while the one in which mass is conserved show QLRO? These questions are being studied at present by simulating both the agent-based model due to Chate with evaporation-deposition and the dynamical equation for the active nematic order-parameter. These studies should clarify the role of concentration in assisting apolar order. It must be borne in mind, however, that numerical simulations of active models are more difficult than their passive counterparts due to the larger number of parameters present in the problem. In passive systems Onsager symmetry relations constrain some parameters. However, the absence of an equivalent rule for systems far away from equilibrium implies that the spatial symmetry allowed couplings will all have independent kinetic coefficients. This increases the size of the parameter space in many problems. Also, many techniques like Monte Carlo have to be carefully modified to suit such systems. A new and exciting area of research from the point of view of statistical mechanics of active systems is an examination of collective behaviour of run-and-tumble particles pioneered by Tailleur and Cates [25]. This has led to fruitful active generalisations of models of dynamic critical phenomena like model B and model H. Also, it has led to an exploration of rules for selecting a state in a region of phase coexistence – an out of equilibrium generalisation of the Maxwell construction. Another interesting avenue is building up active matter equations from microscopics. This has been done for Vicsek model by Thomas Ihle [64,65], for a simple generalisation of Vicsek-type model for both polar and apolar alignment interactions by Bertin et al. and Chate et al. [15, 16, 107], and for a model of hard rods by Marchetti et al. [10, 11]. The issues of closure still remain to be fully resolved however in deriving the macroscopic equations. A particularly exciting new system that has been recently studied extensively is a collection of chemotactic Janus particles [127]. The far-field interaction in this case does not promote polar order but state with proliferation of asters. The coarse-grained hydrodynamic equations have been derived in this case starting from a microscopic picture of colloids coated axisymetrically with a catalyst in an inhomogeneous concentration of reactants by Saha et al. [127]. Another theoretical issue that plagues the derivation of hydrodynamic equations is that of noise. So far most theories have modelled the noise as Gaussian and white, akin to equilibrium systems, but with unknown strength. However, it is likely that the noise also depends on activity, thus requiring a microscopic picture treating the active forces as stochastic quantities. It is known that multiplicative character of the noise induces interesting features at least in the case of active nematics [104]. Thus, a lot of questions need to be answered if theories of active matter have to graduate from merely offering qualitative explanations of biological experiments to becoming the prototypical theory of systems in which energy input and dissipation both occur at a scale smaller than the coarse-graining volume.

Krypgrunder i någon form har använts som grundkonstruktion i Sverige under långtid. Förr var det torpargrunder som med tiden blev isolerade krypgrunder och plintgrunder. Gemensamt för krypgrundskonstruktioner som är ventilerade med utomhusluft är att under sommarhalvåret blir det förhöjda relativa ånghalter. Syftet med fallstudien är att studera en uteluftsventilerad konstruktion med välisolerat bjälklag och markisolering. Konstruktionen är nedgrävd och ventilationen i grunden sker via en tunn spalt under marknivå. Luftspaltens temperatur och relativa ånghalt är av intresse för att avgöra om det finns risken för mögel i konstruktionen. En simulering av värmeflödet mellan byggnad och mark genomförs i COMSOLMultiphysics 5.5 för att avgöra temperaturfördelningen i konstruktionen. Temperaturfördelningen ligger som grund för fastställandet av relativ ånghalt i konstruktionens luftspalt. Simuleringen använder klimatdata för ett typår i Gävle. Simuleringen visar att det är höga temperaturer i luftspalten året runt. Detta ger enrelativ ånghalt som månadsmedel på 37–77% under ett år. Den höga temperaturen iluftspalten bidrar till att hålla konstruktionen torr då kritisk relativ ånghalt, 75–80%, inte överstigs under en längre period. Resultat är förvånansvärt positivt med en låg risk för mögeltillväxt i konstruktionen.Det finns många antaganden framförallt vilket luftflöde som återfinns i luftspalten.För att validera resultaten i arbetet så bör mätningar genomföras på de två prototyphus som existerar. / Crawl spaces in some form have been used as foundations in Sweden for a long time.In the past, it was uninsulated crawl spaces that eventually evolved into insulatedcrawl spaces and open plinth foundations. An increased relative humidity during thesummer is a common problem for crawl spaces that are ventilated with outdoor air. The purpose of the case study is to study an outdoor ventilated structure with wellinsulated floor and ground insulation. The construction is below ground level andthe ventilation takes place via a thin air gap below ground level. The temperatureand relative humidity in the air gap are of interest to determine if there is a risk ofmould growth in the design. A simulation of the heat flow between the building and the ground is carried out inCOMSOL Multiphysics 5.5 to determine the temperature distribution in the design.The temperature distribution is the basis for the determination of relative vaporcontent in the air gap of the structure.The simulation uses climate data for a typicalyear in Gävle. The simulation shows a high temperature in the air gap which gives a relative vaporcontent as a monthly average of 37–77% during a year. The high temperature in theair gap contributes to keeping the structure dry when critical relative humidity, 75–80%, is not exceeded for a longer period of time. The results are surprisingly positive with a low risk of mold growth in the construction.There are many assumptions, in particular, which airflow is found in the airgap. In order to validate the results in the work, measurements should be made onthe two prototype houses that exist.