La théorie des fonctions des croyances offre des outils puissants pour modéliser et traiter les informations imparfaites. En effet, cette théorie peut représenter l'incertitude,l'imprécision et l'ignorance. Dans ce contexte, les données sont stockées dans des bases de données spécifiques qu'on appelle les bases de données crédibilistes. Une base de donnée crédibiliste a deux niveaux d'incertitudes: (i) l'incertitude au niveau des attributs qui se manifeste à travers des degrés de véracité sur les hypothèses des attributs; (ii) l'incertitude au niveau des tuples représentée par des intervalles de confiance sur l'existence des tuples au sein de la table en question. D'autre part, la base de donnée crédibiliste peut être modélisée sous deux formes: (i) la forme compacte caractérisée par un ensemble d'attributs et un ensemble de tuples; (ii) la forme des mondes possibles représentée par un ensemble de base de données candidates où chaque base candidate est une représentation possible de la base de donnée compacte. Interroger la représentation des mondes possibles est une étape fondamentale pour valider les méthodes d'interrogation sur la base compacte crédibiliste. En effet, un modèle de base de donnée est dit système fort si le résultat de l'interrogation de sa représentation compacte est équivalent au résultat de l'interrogation de sa représentation des mondes possibles.Cette thèse est une étude sur les fondements des bases de données crédibilistes. Les contributions sont résumées comme suit:(i) La modélisation et l'interrogation de la base crédibiliste (EDB): Nous mettons en pratique le modèle compacte de la base de données (EDB) en proposant une implémentation objet-relationnelle, ce qui permet d'introduire l'interrogation de ce modèle avec les opérateurs relationnels. D'autres part, nous présentons le formalisme, les algorithmes et les expérimentations d'autres types de requêtes :les top-k évidentiel et le skyline évidentiel que nous appliquons sur des données réelles extraites de la plateforme Tripadvisor.(ii) La modélisation de la base de données sous sa forme des mondes possibles: Nous modélisons la forme de mondes possibles de la base de données (EDB) en traitant les deux niveaux d'incertitudes (niveau attributs et niveau tuples).(iii) La modélisation et l'interrogation de la base de données crédibiliste (ECD): Après avoir prouvé que le modèle des bases de données (ED B) n'est pas un système de représentation fort, nous développons le modèle de la base de données crédibiliste conditionnelle nommée (ECD). Nous présentons le formalisme de l’interrogation sur les deux formes (compacte et mondes possibles) de la base de données (ECD). Finalement, nous discutons les résultats de ces méthodes d'interrogation et les spécificités du modèle (ECD). / The theory of belief functions (a.k.a, the Evidence Theory) offers powerful tools to mode! and handle imperfect pieces of information. Thus, it provides an adequate framework able to represent conjointly uncertainty, imprecision and ignorance. In this context, data are stored in a specific database model called evidential databases. An evidential database includes two levels of uncertainty: (i) the attribute level uncertainty expressed via some degrees of truthfulness about the hypotheses in attributes; (ii) the tuple level uncertainty expressed through an interval of confidence about the existenceof the tuple in the table. An evidential database itself can be modeled in two forms:(i) the compact form represented as a set of attributes and a set of tuples; (ii) the possible worlds' form represented as a set of candidate databases where each candidate is a possible representation of the imperfect compact database. Querying the possible worlds' form is a fundamental step in order to check the querying methods over the compact one. In fact, a model is said to be a strong representation system when results of querying its compact form are equivalent to results of querying its non compact form.This thesis focuses on foundations of evidential databases in both modeling and querying. The main contributions are summarized as follows:(i) Modeling and querying the compact evidential database (EDB): We implement the compact evidential database (EDB) using the object-relational design which allows to introduce the querying of the database model under relational operators. We also propose the formalism, the algorithms and the experiments of other typesof queries: the evidential top-k and the evidential skyline that we apply over a real dataset extracted from TripAdvisor.(ii) Modeling the possible worlds' form of (EDB): We model the possible worlds' form of the evidential database (EDB) by treating both levels of uncertainty (the tuple leve! and the attribute level).(iii) Modeling and querying the evidential conditional database (ECD): After provingt hat the evidential database (EDB) is not a strong representation system, we develop a new evidential conditional database model named (ECD). Thus, we present the formalism of querying the compact and the possible worlds' forms of the (ECD) to evaluate the querying methods under relational operators. Finally, we discuss the results of these querying methods and the specificities of the (ECD)model.

Community detection in networks is an important area of current research with many applications. Finding community structures is a challenging task and despite significant effort no satisfactory method has been found. Different methods find different communities in the same network and with different computational requirements. To counter this problem, several different methods are often used and the results compared manually. In this thesis, we present three different methods to instead merge the results from different methods (or several runs from the same algorithm) to find better estimates of the community structure. Another problem in practical applications is noisy and imperfect networks with missing and false edges. These imperfections are natural results from the methods used to map the network structure and are often difficult to eliminate. In this thesis, we apply a Monte Carlo-sampling method in combination with the introduced methods for merging community detection results to find community structures in such networks. The method is tested by simulation studies on both real-world networks and synthetic networks with generated uncertainties and imperfections. We finally demonstrate how it is possible to generate confidence levels of the obtained community structure from the merging methods. This allows for a qualitative comparison of the robustness and significance of the network clustering. / Identifikation av grupperingar i nätverk är ett viktigt område inom aktuell forskning med många olika tillämpningsområden. Att finna grupperingar är ofta svårt och trots betydande ansträngningar har ingen tillfredsställande metod hittats. Olika metoder finner ofta olika grupperingar i samma nätverk och kräver varierande beräkningskraft. För att hantera dessa problem används ofta flera metoder vartefter resultaten jämförs manuellt. I detta examensarbete presenterar vi tre olika metoder att istället slå samman resultat från olika metoder (eller fler körningar från samma algoritm) för att hitta bättre uppskattningar av grupperingarna. Ett annat problem i praktiska tillämpningar är brus och ofullständiga nätverk med saknade och falska kanter. Dessa brister är naturliga resultat från de metoder som används för att kartlägga nätverketstrukturen och det är ofta svåra att eliminera dessa. I detta examensarbete använder vi Monte Carlo-metoder i kombination med de introducerade metoderna för att slå samman funna grupperingar för att hitta grupperingar i det osäkra nätverket. Vi testar metoden genom simuleringstudier på både verkliga och syntetiska nätverk med genererade osäkerheter och brister. Slutligen demostrerar vi hur det är möjligt att skapa konfidensnivåer för noder i grupperingar med hjälp av metoderna för sammanslagning. Detta möjliggör en kvalitativ jämförelse av stabilitet och signifikans av identifierade nätverksgrupperingar.

In this thesis, we analyze the impact of the decentralization of price and leadtime decisions made by the marketing and production departments, respectively, in a make-to-order firm. We first study a monopoly environment, and find that in the decentralized setting, the total demand generated is larger, leadtimes are longer, quoted prices are lower, and the firm profits are lower as compared to the centralized setting. We show that coordination can be achieved using a transfer price contract with bonus payments, where both departments receive a fraction of the total revenues generated as a bonus payment. In the second study, we extend this work to a duopoly environment, where two firms compete on the basis of their price and leadtime quotes in a common market. We find that under intense price competition, firms may suffer from a decentralized structure, particularly under high flexibility induced by high capacity, where revenue based sales incentives motivate sales/marketing for more aggressive price cuts resulting in eroding margins. We take the parameters of the demand models in the first two studies as constant, while estimating those parameters based on historical data is a very important problem in practice. In the last study of this thesis, we address the challenges encountered in estimating the price sensitivity of customers shifting focus to the passenger travel industry. We explore how to obtain better price elasticity estimates through an empirical study with an emphasis on the endogeneity problem, which arises as a result of the simultaneous determination of supply and demand. We show that if one does not account for endogeneity, price elasticities may induce an upward-sloping demand curve suggesting that high price produces high demand, or may be biased downward to the extent that elastic demand curves are incorrectly classified as inelastic. We show the improvement in price elasticities through an instrumental variable approach.

This thesis is an investigation of how subjects behave in an individual binary choice decision task with the option to purchase or observe for free additional information before reaching a decision. In part 1 of this thesis, an investigative study is conducted with the intent to sharpen the view to literature concerning corresponding psychology and economics experiments designed to test decision tasks that involve purchasing and observing information from an imperfect message prior to taking a terminal action choice. This investigative study identifies areas of research that warrant further investigation as well as provides enhancements for execution in the subsequent experiment conducted in Part 2 & 3 of this thesis. In Part 2 & 3, I conduct an experiment to test how subjects behave in an individual binary choice decision task with the option to purchase or observe for free additional information before reaching a final decision. I find that subjects’ behaviour over time converges toward optimal decisions prior to observing an imperfect information signal. However, when subjects observe an imperfect information signal prior to their terminal choice there is greater deviation from optimal behaviour. I find in addition to behaviour that is reflective of a risk-neutral BEU maximizer, status quo bias, over-weighing the informational value of the message received and past statistically independent outcomes influencing future choices. The subjects’ willingness to pay (WTP) to use the additional information gathered from an imperfect message service when making a final decision was on average less than the risk neutral BEU willingness to pay benchmark. Moreover, as the informative value of the message increased, causing the BEU valuation to increase, subjects under-estimated the value of the message signal to a greater degree. Although risk attitudes may have influenced the subjects’ WTP decisions, it does not account for the increased conservative WTP behaviour when information became more valuable. Additionally, the findings from this study suggest that individuals adopt different decision rules depending on both personal attributes (i.e. skillset, gender, experience) and on the context and environment in which the decision task is conducted. / SSHRC grant: Social Sciences and Humanities Research Council via Dr. Bram Cadsby Professor Department of Economics, University of Guelph

This dissertation is a collection of essays (chapters) on behavioral economics. Behavioral economics—arguably one of the most influential innovations in economics over the last 20 years—is a research paradigm introducing psychologically more realistic assumptions into economics. A common theme throughout the dissertation is the focus on either biased beliefs, or heterogeneous preferences, or both. The first chapter serves as an introduction to some themes in behavioral economics and its implications for market outcomes in industrial organization settings. The next two chapters are theoretical papers on entrepreneurial and managerial overconfidence that can also be thought of as contributions to this newly emerging field of behavioral industrial organization. The last chapter is an empirical contribution on gender differences in preferences and economic behavior at a young age. / <p>Diss. Stockholm : Handelshögskolan, 2011</p>

This thesis consists of four independent essays, which consider different topics in information economics and political economy. The first two papers are variants of the same idea. An uninformed principal, e.g., a government, will make a decision. In order to gain more information it may consult two experts; however, these experts have a private interest in certain policies being implemented. The question is, to gain as much information as possible, should the principal consult experts who are biased in the same direction, or experts who prefer different decisions? The main result is that, as long as collusion between experts can be prevented, homogeneous panels are superior to heterogeneous ones, and this advantage increases with the experts’ informational precision. In the third paper, two firms consider entry in a new product market and must decide when to enter the market and how to design their product. Firms do not know for certain what the best design is, so both firms want to outwait the other’s decision in order to gain more information. The focus of the paper is on which firm will make the first decision. The main result is that if products are strong (strategic) substitutes, the worst informed firm makes the first decision in equilibrium. The analysis should apply to a range of other contexts, such as investors’ trading decisions or the policy choices of political candidates. The final paper asks the following question: Could it be that parties in a two-party system may benefit from using several candidates in the same election? To promote the use of multiple candidates, I assume that a party never runs the risk of having its votes split up among its candidates. Despite this, it turns out that parties have a strong incentive to restrict their number of nominees. Paradoxically, it seems that the more uncertain parties are about voter opinion, the fewer candidates they want to use. In particular, with a uniform voter distribution the optimal number of candidates is one. / Diss. Stockholm : Handelshögsk., 2001 S. v-vii: sammanfattning, s. 1-72: 4 uppsatser

In this thesis I evaluate the departures of three common assumptions in macroeconomic modeling and estimation, namely the Rational Expectations (RE) hypothesis, the representative agent assumption and the use of first-order approximations in the estimation of dynamic stochastic general equilibrium (DSGE) models. In the first chapter I determine how the use of survey data on inflation expectations in the estimation of a model alters the evaluation of the RE assumption in comparison to an alternative assumption, namely learning. In chapter two, I use heterogeneous agent models to determine the relationship between income volatility and the demand for durable goods. In the third chapter I evaluate if the use of first-order approximations in the estimation of a model could affect the evaluation of the determinants of the Great Moderation. / En esta tesis analizo desvíos de tres supuestos comunes en la elaboración y estimación de modelos macroeconómicos. Estos supuestos son la Hipótesis de Expectativas Racionales (ER), el supuesto del Agente Representativo, y el uso de aproximaciones de primer orden en la estimación de los modelos de equilibrio general. En el primer capítulo determino como el empleo de datos de expectativas de inflación en la estimación de un modelo puede alterar la evaluación del supuesto de ER en comparación a un supuesto alternativo como learning. En el segundo capítulo, utilizo modelos de agentes heterogéneos para determinar la relación entre la volatilidad de los ingresos y la demanda de bienes durables. En el tercer capítulo, analizo si el uso de aproximaciones de primer orden afecta la evaluación de los determinantes de la Gran Moderación.

Dans la plupart des activités quotidiennes, l’Homme a tendance à utiliser des connaissances imparfaites. L’imperfection se rapporte à trois volets : l’imprécision, l’incertitude et l’incomplétude. Nous thèse concerne les connaissances imprécises. En particulier, nous nous intéressons au traitement qualitatif de l’information imprécise dans les systèmes à base de connaissances. Diverses approches ont été proposées pour traiter les connaissances imprécises, en particulier, la logique floue et la logique multivalente. Les théories des ensembles flous et des multi-ensembles sont un moyen très approprié pour la représentation et la modélisation de l’imprécision.Notre travail s’inscrit dans le contexte de la logique multivalente. Celle-ci permet de représenter symboliquement des connaissances imprécises en utilisant des expressions adverbiales ordonnées du langage naturel. L’utilisation de ces degrés symboliques est plus compréhensible par les experts. Ce type de représentation de données est indépendant du type de leurs domaines de discours. Ainsi, la manipulation des connaissances abstraites ou faisant référence à des échelles numériques se fait de la même manière.Dans la littérature, le traitement de l’information imprécise repose sur une hypothèse implicite de la répartition uniforme des degrés de vérité sur une échelle de 0 à 1. Néanmoins, dans certains cas, un sous-domaine de cette échelle peut être plus informatif et peut inclure plus de termes. Dans ce cas, l’information est définie par des termes déséquilibrés, c’est-à-dire qui ne sont pas uniformément répartis et/ou symétriques par rapport à un terme milieu. Par exemple, pour l’évaluation des apprenants, il est possible de considérer un seul terme négatif F correspondant à l’échec. Quant à la réussite, elle est décrite par plusieurs valeurs de mention, i.e. D, C, B et A. Ainsi, si le terme D est le seuil de la réussite, il est considéré comme le terme milieu avec un seul terme à sa gauche et trois à sa droite. Il s’agit alors d’un ensemble non uniforme.Dans ce travail, nous nous concentrons sur l'extension de la logique multivalente au cas des ensembles non uniformes. En s'appuyant sur notre étude de l'art, nous proposons de nouvelles approches pour représenter et traiter ces ensembles de termes. Tout d'abord, nous introduisons des algorithmes qui permettent de représenter des termes non uniformes à l'aide de termes uniformes et inversement. Ensuite, nous décrivons une méthode pour utiliser des modificateurs linguistiques initialement définis pour les termes uniformes avec des ensembles de termes non uniformes. Par la suite, nous présentons une approche de raisonnement basée sur le modèle du Modus Ponens Généralisé à l'aide des Modificateurs Symboliques Généralisés. Les modèles proposés sont mis en œuvre dans un nouveau système de décision fondé sur des règles pour la reconnaissance de l'odeur de camphre. Nous développons également un outil pour le diagnostic de l'autisme infantile. Les degrés de sévérité de l'atteinte par ce trouble autistique sont représentés par l'échelle d'évaluation de l'autisme infantile (CARS). Il s'agit d'une échelle non uniforme. / In most daily activities, humans use imprecise information derived from appreciation instead of exact measurements to make decisions. Various approaches were proposed to deal with imperfect knowledge, in particular, fuzzy logic and multi-valued logic. In this work, we treat the particular case of imprecise knowledge.Taking into account imprecise knowledge by computer systems is based on their representation by means of linguistic variables. Their values form a set of words expressing the different nuances of the treated information. For example, to judge the beauty of the Mona Lisa or the smell of a flower, it is not possible to give an exact value but an appreciation is given by a term like "beautiful" or "floral".In the literature, dealing with imprecise information relies on an implicit assumption: the distribution of terms is uniform on a scale ranging from 0 to 1. Nevertheless, in some cases, a sub-domain of this scale may be more informative and may include more terms. In this case, knowledge are represented by means of an unbalanced terms set, that is, not uniformly nor symmetrically distributed.We have noticed, in the literature, that in the context of fuzzy logic many researchers have dealt with these term sets. However, it is not the case for multi-valued logic. Thereby, in our work, we aim to establish a methodology to represent and manage this kind of data in the context of multi-valued logic. Two aspects are treated. The first one concerns the representation of terms within an unbalanced multi-set. The second deals with the treatment of such kind of imprecise knowledge, i.e. with symbolic modifiers and in reasoning process.In this work, we focus on unbalanced sets in the context of multi-valued logic. Basing on our study of art, we propose new approaches to represent and treat such term sets. First of all, we introduce algorithms that allow representing unbalanced terms within uniform ones and the inverse way. Then, we describe a method to use linguistic modifiers within unbalanced multi-sets. Afterward, we present a reasoning approach based on the Generalized Modus Ponens model using Generalized Symbolic Modifiers. The proposed models are implemented in a novel rule-based decision system for the camphor odor recognition within unbalanced multi-set. We also develop a tool for child autism diagnosis by means of unbalanced severity degrees of the Childhood Autism Rating Scale (CARS).

Submitted by Mariam Magnavita (mariamhusein@hotmail.com) on 2018-03-22T17:46:49Z No. of bitstreams: 1 disst_mariam (1).pdf: 2119380 bytes, checksum: 2e8cd3fe1d01776ae2a701375db5f10c (MD5) / Approved for entry into archive by Maria Auxiliadora da Silva Lopes (silopes@ufba.br) on 2018-03-26T17:37:03Z (GMT) No. of bitstreams: 1 disst_mariam (1).pdf: 2119380 bytes, checksum: 2e8cd3fe1d01776ae2a701375db5f10c (MD5) / Made available in DSpace on 2018-03-26T17:37:03Z (GMT). No. of bitstreams: 1 disst_mariam (1).pdf: 2119380 bytes, checksum: 2e8cd3fe1d01776ae2a701375db5f10c (MD5) / A inclusão escolar de alunos com deficiência é um dos elementos chave da atual política de educação inclusiva brasileira, assim, é cada vez maior o número desses alunos na escola regular. Entretanto, muitas vezes, a escola não dispõe dos meios adequados para oferecer a esse alunado uma educação de qualidade. É neste con-texto que alunos com osteogênese imperfeita (OI) são incluídos na escola regular. A OI é uma doença rara que tem como principal característica a fragilidade óssea. Alunos com esta patologia desenvolvem deficiência física, necessitam de cuidados constantes para evitar a ocorrência de fraturas e de tratamento médico regular, o que os afastam da escola periodicamente, podendo passar longos meses sem fre-quentar as aulas para tratar das fraturas recorrentes ou de complicações da doença. Assim, estudantes com OI necessitam dos recursos e apoios oferecidos pela Educa-ção Especial. Diante disso, este estudo teve como objetivo precípuo analisar o pro-cesso de inclusão escolar de alunos com OI que realizam o tratamento para a doen-ça em um hospital universitário localizado no município de Salvador, no Estado da Bahia. Para tanto, foi empreendida uma pesquisa de caráter qualitativo constituída de um estudo de caso realizado com 5 adolescentes com OI e suas mães, totalizan-do 10 participantes de pesquisa. Para coletar os dados foram utilizados 3 instrumen-tos: a entrevista estruturada, a entrevista semiestrururada e a análise documental. A análise dos dados foi realizada segundo o método de análise de conteúdo descrito por Bardin (2011). Os resultados revelaram que os alunos com osteogênese imper-feita não encontram na escola regular todas as condições necessárias para sua ple-na participação nas atividades de ensino-aprendizagem, pois há falta de acessibili-dade nas escolas desses estudantes, assim como existem barreiras pedagógicas e atitudinais que interferem em seu processo de inclusão escolar. A pesquisa revelou, ainda, que as iniciativas das escolas para diminuir as consequências das interrup-ções na frequência escolar desses educandos ou não existem ou se mostram insuficientes para contribuir de maneira efetiva para seu retorno à escola. / ABSTRACT The school inclusion of students with disabilities is one of the key elements of the current policy of inclusive Brazilian education, thus, the number of these students in the regular school is increasing. However, it is common that the school does not have the appropriate means to offer this student a quality education. It is in this con-text that students with osteogenesis imperfecta (OI) are included in the regular school. The OI is a rare disease that has bone fragility as its main characteristic. Stu-dents with this pathology develop a physical deficiency in a progressive way, they need constant care to avoid the occurrence of fractures and periodic medical treat-ment, which deviate them from school periodically, and they can spend many months without attending classes to treat recurrent fractures or complications of the disease. Thus students with osteogenesis imperfecta need the resources and support offered by Special Education. Therefore, this study aimed to analyze the process of school inclusion of students with OI who makes the treatment for the disease in a university hospital located in Salvador city, State of Bahia. For that, a qualitative research was carried out, constituted in a case study carried out with 5 adolescents with OI and their mothers, totaling 10 research participants. Three instruments were used to col-lect the data, the structured interview, the semi-structured interview and the docu-mentary analysis. Data analysis was performed according to the content analysis method described by Bardin (2011). The results showed that students with osteo-genesis imperfecta do not find in the regular school all the necessary conditions for their full participation in teaching-learning activities, since there is a lack of accessibil-ity in the schools of these students, as well as there are pedagogical and attitudinal barriers that interfere in their process of school inclusion. The research also revealed that the initiatives of schools to reduce the consequences of interruptions in the school attendance of these students do not exist or are insufficient to contribute ef-fectively to their return to school.

The goal of this work is the study of the alternation between two verb tenses Futuro do Pretérito ( Future of Past Tense) and Pretérito Imperfeito of the Indicativo (Imperfect Tense) in main clauses of hypothetical contexts in the speech of alagoanos (people who live in Alagoas, in the northeast of Brazil). We adopt as the theoretical and methodological framework the theory of Linguistic Variation (LABOV, 1972). The alternation between these two verb tenses becomes possible because of the fact that these tenses share the property to refer to unfinished/unbounded events/actions. What puzzles us is the reason(s) that makes a speaker choose one or another verb tense. We start from the hypothesis that the Imperfect Tense supersedes the Future of Past Tense in main clauses of hypothetical contexts of spoken language. In this dissertation we intend to verify what linguistic and non-linguistic variables are statistically significant in terms of VARBRUL for the dependent variable. For this purpose, we selected as external factors age, gender and educational level; and as internal factors we selected the formal parallelism and the order of the clause. / Conselho Nacional de Desenvolvimento Científico e Tecnológico / O presente trabalho tem como objeto de estudo a variação entre o futuro do pretérito (FP) e o pretérito imperfeito do indicativo (PII) na oração principal em contextos hipotéticos na fala de alagoanos. Seguimos como pressuposto teórico/metodológico o da Teoria da Variação Linguística, representado por William Labov (1972), uma vez que a variação é algo inerente à língua, já que ela é indissociável da comunidade que a fala e não existe comunidade linguística homogênea (BELINE, 2003). A alternância entre os tempos verbais (FP) e (PII) se torna possível pelo fato de esses verbos compartilharem a possibilidade de manifestar traços de aspecto inconcluso. O que nos intriga é (são) o (s) motivo (s) que leva (m) o falante a optar por uma forma ou outra. Partimos da hipótese de que o (PII) suplanta o (FP) na oração principal em contextos hipotéticos, na língua falada. Nesta dissertação buscamos, portanto, verificar quais variáveis linguísticas e não linguísticas são estatisticamente significativas na rodagem do VARBRUL para a variável dependente. Para tanto, selecionamos como fatores externos: a idade, o sexo e a escolaridade; e como fatores internos: o paralelismo formal e a ordem da sentença.