This thesis is composed of three essays. The first essay studies price setting behavior by sales agents of an electrical wholesale company following a change in their compensation contract. Originally, agents received a fixed share of the revenues from their sales. Under the new scheme, commission rates increase with the price-cost margin of the sale. The reform was enacted at different times in different stores, enabling measurement of its impact by difference-in-differences. Commissions on 95% of goods increase but agents do not raise prices on all these products. Despite the stronger financial incentives, the price of 18% of goods decreases and increases for the rest, suggesting agents reallocate effort among products. The second essay explores the importance of employee-customer relationships as an incentive and price discriminating tool. The model assumes that customers differ in their valuations and in their probability of returning (q). The distribution of valuations and q are known, and in each interaction the sales agent exerts effort to learn the customer’s valuation. The agent earns a commission based on the client’s payment and has full pricing flexibility. The two main insights are that, when the valuation is unknown, effort is increasing in q and the effect of a commission raise has an inverted-U relation with customers’ probability of returning. Prices should be increasing in effort. Using administrative data from an electrical company, I show evidence supporting the theoretical insights. The third essay analyses the determinants of teachers’ occupational choice and how changes in financial incentives modify individuals’ occupation choices. Among college graduates, teachers have both low average Armed Forces Qualification Test scores (AFQT) and high average risk aversion. Using a dynamic optimization model with unobserved heterogeneity, we find that were it possible to make teacher compensation mimic the return to skills and riskiness of the non-teaching sector, overall compensation in teaching would increase. Moreover, such a shift would substantially reduce the utility of many current teachers, making the process of reform challenging. Importantly, the results of policy exercises are very sensitive to the degree of heterogeneity included in the model.

Cette thèse traite du mouvement respiratoire dans l'imagerie TEP/TDM. L'imagerie TEP est une modalité à exposition longue très influencée par les mouvements involontaires du patient. Ces mouvements produisent des artéfacts dont les conséquences sont sérieuses pour le diagnostic car les tumeurs paraissent plus larges et moins actives. Cette thèse contribue à la résolution de ce problème. En plus de proposer l'architecture d'un système d'acquisition TEP/TDM synchronisée à la respiration, on y développe trois méthodes de traitement de signal et d'images qui peuvent être appliquées pour résoudre différents sous-problèmes: Une méthode originale de segmentation et caractérisation du signal respiratoire pour découvrir les patterns respiratoires "normaux" du patient, une méthode de reconstruction TDM-4D qui permet d'obtenir des images anatomiques du corps à chaque niveau respiratoire désiré et un algorithme itératif amélioré pour reconstruire des images TEP-4D compensées en mouvement respiratoire. Toutes ces méthodes et algorithmes ont été validés et testés sur des données simulées, des données de fantômes, et des données réelles de patients. / This thesis deals with respiratory motion in PET/CT images. It is well known that PET is a modality that requires a long exposure time. During this time, patients moves and breath. These motions produce undesirable artefacts that alter seriously the images and their precision. This has important consequences when diagnosing thoracic, and particularly pulmonary, cancer. Tumours appear larger than they really are and their activity is weaker. This thesis proposes to contribute to solving these problems.We propose the architecture of an integrated PET/CT acquisition system synchronized to respiration. We also develop signal and image processing methods that can be applied to eliminating respiratory artefacts in CT and PET images. The thesis brings three main contributions : An original respiratory signal segmentation and characterization to detect "normal" respiratory patterns, a 4D-CT reconstruction method that creates 3D images of the whole body for any respiratory level and an enhanced iterative algorithm for reconstructing 4D-PET images without respiratory artefacts. The developed methods have validated and tested on simulated, phantom and real patients' data.

Le travail présenté dans ce mémoire s’est déroulé dans le cadre d’une collaboration entre le groupe Convertisseur Statique du laboratoire LAPLACE et le département " Installations Fixes de Traction Electrique " de la Direction de l’Ingénierie de la SNCF. Aujourd'hui, la majorité du trafic sur le réseau ferré monophasé 25 kV / 50 Hz est assurée par des locomotives équipées de redresseurs contrôlés à thyristors. Du fait de l'augmentation du trafic, l'utilisation de ces locomotives nécessite la mise en place de moyen de compensation de puissance réactive afin de maintenir la tension caténaire à un niveau acceptable et de réduire la facture en énergie réactive. La correction du facteur de déplacement est réalisée en partie par des batteries de compensation fixes dont lapuissance est limitée par la tension maximale admissible à vide sur la caténaire. Afin d’adapter le niveau de compensation à la consommation, la partie fixe est complétée par un dispositif réglable basé sur une réactance contrôlée par des thyristors. Bien qu’il soit simple dans son principe, ce dispositif nécessite un filtrage des harmoniques en basse fréquence avec des circuits LC volumineux. L’objectif de cette thèse est de proposer une nouvelle topologie de compensateur de puissance réactive à haut rendement et utilisant un contrôle à modulation de largeur d’impulsion dans le but de minimiser le volume des éléments de filtrage. La première partie de ce mémoire est consacrée à une étude comparative de différentes topologies du point de vue des pertes dans les semi-conducteurs et du dimensionnement des éléments de filtrage associés. Les résultats de cette étude montrent que les topologies à base de gradateurs MLI, constituent les solutions les plus intéressantes pour réaliser le compensateur. La deuxième partie du travail concerne l’étude de l’insertion d’un compensateur à base de gradateurs MLI sur le réseau ferré avec la prise en compte des interactions harmoniques. Le cas d’étude concerne une sous-station où doit être implantée une compensation variable de 3 MVAR. Un relevé des courants délivrés par la sous-station a été effectué dans le but d’analyser leur contenu harmonique. Une modélisation de la sous-station et du compensateur est ensuite proposée et des simulations temporelles de l’ensemble sont réalisées en prenant en compte les formes d’ondes réelles des courants absorbés par les trains. Finalement, cette étude par simulation permet d’affiner le dimensionnement du compensateur à gradateurs MLI et des éléments de filtrage associés. Elle met en évidence l’avantage d’une solution, avec des gradateurs MLI en montage élévateur de tension, qui fonctionne sans transformateur et réutilise les batteries de compensation fixes déjà installées en sous-station à la fois comme diviseur de tension et éléments de filtrage. Afin de valider le principe de cette nouvelle topologie de compensateur statique de puissance réactive, un démonstrateur de 1,2 MVAR est mis en oeuvre et testé sur une plateforme d'essai de la SNCF. / The work presented in this thesis is the result of collaboration between the Static Converters research group of LAPLACE Laboratory and the department "Installations Fixes de Traction Electrique" of the Engineering Division of the French Railways company, SNCF. Nowadays, most of the traffic in 25 kV – 50 Hz lines is achieved by old locomotives equipped with thyristor rectifiers. As traffic and load increase, reactive power compensation devices are required to keep the overhead line voltage at acceptable level and to reduce the spending for reactive power. The basic power factor correction is completed by fixed compensation banks. But the difficulty of such configuration is the no-load operation of overhead lines. The voltage can increase out of the 29 kV standard limit and to avoid this problem, variable reactive power compensator is often added to the fixed compensation banks. Nowadays, SNCF is equipped with thyristor based static VAR compensators (SVC). The main drawback of this topology is the requirement of a large LC shunt filter tuned for the third harmonic. The goal of this thesis is to find a new high-efficiency topology of STATic COMpensator (STATCOM) using PWM control to minimize the filtering components. The first part of this thesis focuses on a comparative study of different topologies in terms of semiconductor losses and filter elements size. The results of this study show that the topologies based on PWM AC Chopper are the most interesting solutions to achieve the compensator. The second part of the work concerns the influence of the connection of a STATCOM to a substation and focuses on the harmonic interactions with locomotives. The study case concerns a high traffic substation where a 3 MVAR STATCOM should be installed. Substation output current measurement was carried out in order to analyze its harmonic content. Models of the substation and the STATCOM are then proposed and simulations using real current waveforms are performed. Finally, this simulation study helps to refine the features of the AC Chopper topology and its filter elements. It highlights the advantage of a solution, with boost AC Choppers which operate without transformer and reuse the fixed compensation banks already installed in the substation as voltage divider and filter. To validate the principle of this new topology of STATCOM, a 1.2 MVAR prototype is built in LAPLACE laboratory and tested on a SNCF test platform.

La délégation du pouvoir de gestion aux administrateurs et aux gestionnaires, une caractéristique intrinsèque à la gestion efficace de grandes entreprises dans un contexte de capitalisme, confère une grande discrétion à l’équipe de direction. Cette discrétion, si elle n’est pas surveillée, peut mener à des comportements opportunistes envers la corporation, les actionnaires et les autres fournisseurs de capital qui n’ont pas de pouvoir de gestion. Les conflits entre ces deux classes d’agents peuvent émerger à la fois de décisions de gouvernance générale ou de transactions particulières (ie. offre publique d’achat). Dans les cas extrêmes, ces conflits peuvent mener à la faillite de la firme. Dans les cas plus typiques, ils mènent l’extraction de bénéfices privés pour les administrateurs et gestionnaires, l’expropriation des actionnaires, et des réductions de valeur pour la firme. Nous prenons le point de vue d’un petit actionnaire minoritaire pour explorer les méchanismes de gouvernance disponibles au Canada et aux États‐Unis. Après une synthèse dans la Partie 1 des théories sous‐jacentes à l’étude du pouvoir dans la corporation (séparation de la propriété et du contrôle et les conflits d’agence), nous concentrons notre analyse dans la Partie 2 sur les différents types de méchanismes (1) de gouvernance interne, (2) juridiques et (3) marchands, qui confèrent du pouvoir aux deux classes d’agents. Nous examinons comment les intérêts de ces deux classes peuvent être réalignés afin de prévenir et résoudre les conflits au sein de la firme. La Partie 3 explore un équilibre dynamique de pouvoir corporatif qui cherche à minimiser le potentiel d’opportunisme toute en préservant une quantité de discrétion suffisante pour la gestion efficace de la firme. Nous analysons des moyens pour renforcer les protections des actionnaires minoritaires et proposons un survol des pistes de réforme possibles. / The delegation of power to corporate directors and officers (Insiders), an essential trait of modern firm management in the context of capitalism, presents desirable efficiency advantages. However, it also confers broad discretion to Insiders . This discretion, when unchecked, may lead to self‐interested opportunistic behaviour detrimental to the firm and to the outside shareholders (Outsiders) who supply finance to the firm but do not have management power. Conflicts between Insiders and Outsiders may emerge from either general governance decisions or from particular transactions (ie. takeovers). In extreme cases, these conflicts can lead to the bankruptcy of the firm or, in more typical cases, to the extraction of private benefits for Insiders, shareholder expropriation and value‐reducing actions for the firm. We take the perspective of an outside shareholder to explore corporate governance mechanisms available in the US and Canada. After reviewing in Part 1 the core theories underlying the study of power in the modern corporation (separation of ownership and control and agency conflicts), we focus in Part 2 on the (1) internal governance, (2) regulatory and (3) market mechanisms through which both Insiders and Outsiders draw power. We examine how Outsiders can harness these mechanisms to check Insiders, as well as to prevent and resolve various types of conflicts. In Part 3, we explore a corporate power equilibrium that helps to minimize Insider opportunism, while reserving sufficient Insider discretion for effective firm management. We make the case for strengthening protections for shareholders and provide an overview of potential legislative reform paths.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

This research presents the results of general linear modeling (GLM) of 131 school divisions in Virginia. The purpose of this research is to answer the question: What is the relationship between teacher salaries and student achievement as measured by Adequate Yearly Progress (AYP)? Utilizing an equity theory and distributive justice perspective, data related to achievement in English and mathematics by high school students, as measured by the requirements of AYP, were culled from the Virginia Department of Education for every school division in Virginia in the subjects of reading, writing, algebra I, geometry, and algebra II. These data represent the dependent variables and are analyzed with teacher salary and principal salary data, which represent the independent variables. Intervening variables identified in the education, public policy and economic literature are also included in the modeling. An analysis of nine general linear models produced evidence that the relationship between teacher salaries and student achievement, as measured by AYP, is relatively weak. Though the results do not support a wide range of policy recommendations, one recommendation is for school divisions in the northern region of the state to consider a readjustment of their pay scales in order for teacher salaries in those Northern Virginia school divisions to be more competitive with other school divisions in the state when adjusted for cost-of-living.

This study investigates the effects of insider entrenchment on Chief Executive Officer (CEO) compensation in firms conducting an initial public offering (IPO). The sample comprises 220 US firms that went public between 1996 and 2002. Corporate governance choices regarding entrenchment are captured by six provisions in the corporate charter and bylaws, as well as five anti-takeover statutes, which may or may not be in effect in the state of incorporation. Firm-level items are supermajority requirements for charter amendments, bylaws amendments, and merger approvals, along with the presence or absence of a staggered board of directors, poison pills, and golden parachute agreements. The anti-takeover laws examined are Business Combination, Control Share Acquisition, Fair Price, Poison Pill Endorsement, and Constituencies Statutes. A factor analysis reveals three distinct components of entrenchment: firm- and state-level external entrenchment and firm-level internal entrenchment. External entrenchment is related to market control over management by means of corporate takeovers; internal entrenchment relates to shareholder control over management by means of their voting power. Evidence is found for a positive association between entrenchment at IPO and subsequent CEO cash and total compensation. These relationships are driven by firm-level external entrenchment. Firm-level external entrenchment is also significantly and positively associated with CEO stock-based compensation. The positive effects of entrenchment at IPO on CEO compensation appear not to be transitory and remain constant for at least five years post-IPO. Furthermore, entrenchment at IPO is shown to affect CEO pay-for-performance sensitivity. On balance, entrenchment reduces the sensitivity of CEO compensation to stock returns and returns on assets. The results of this study underscore the crucial importance of insiders' governance decisions made at the time of the IPO. Little support is found for a re-balancing of components of the CEO's compensation contract in response to entrenchment as predicted under the optimal contracting theory of compensation contracts. The findings of this study are almost entirely consistent with the managerial power theory, according to which entrenchment at IPO causes a permanent shift in bargaining power, which enables CEOs to influence compensation contracts in their favor.

A modern society is often characterized by a large measure of welfare that all citizens take part of to a greater or lesser extent. Welfare can be defined as the social rights and benefits enjoyed by the habitants of a country. In Sweden, the social safety net is well developed and offers financial compensation in several situations and the individual can safely rely on the social safety net. In addition, legislations and insurances have been developed to offer protection to the habitants in special deserving cases. For example, when a person gets injured at the work-place or in traffic there are insurances that allow compensation regardless of any negligence, so called culpa. The insurance form is called no fault insurances. In addition, there is tort law that is applicable on all non-contractual damages. Tort law, private insurance law, insurances due to collective bargaining, public insurances covering occupation as well as different areas of the social security system are all connected in a vast and complex structure. The main purpose of the essay is to analyze the interdependence between the different compensation systems and to examine the differences that the no fault insurances concerning work related injuries and injuries due to traffic shows between them but also in comparison with tort law regarding for example compensation and the possibility to appeal a “wrongfully” made decision. The first part of the essay will provide a historical background to the development of the no fault insurances, especially regarding occupational damage and accidents in traffic, and focus on the relation between the different compensation systems - the Swedish model. Further on the motives to the regulations will be examined, followed by cases illustrating the actual application and specialness of the regulations. Analyzes and conclusions will be found in the different chapters of the essay, and they will be put together in a final chapter.

Recentemente os sistemas de transferência de energia sem fio WPT (do inglês Wireless Power Transfer) têm sido amplamente estudados com o propósito de alimentar eficientemente diversos tipos de cargas através de técnicas específicas, dentre elas destaca-se a transferência capacitiva de potência CPT (do inglês Capacitive Power Transfer) e a transferência indutiva de potência IPT (do inglês Inductive Power Transfer), sendo esta última objeto deste estudo. Em um sistema de transferência indutiva de potência a carga é alimentada através de um transformador fracamente acoplado. Em função do elevado espaçamento entre as bobinas primária e secundária, da ausência de núcleo magnético, ou o emprego do núcleos divididos e separados por um grande entreferro, o transformador apresenta alta reatância de dispersão e baixa reatância de magnetização, o que resulta em elevadas correntes, baixa eficiência e regulação da tensão ruim quando houver variação da carga. Com o intuito de aumentar a eficiência e melhorar a regulação de tensão (ou corrente) são aplicadas compensações capacitivas em ambos os lados do transformador, elevando o número de elementos reativos, o que dificulta a compreensão do seu comportamento. Adicionalmente, as diversas configurações geométricas possíveis para a construção das bobinas dificultam a otimização do projeto de transferência indutiva de potência. Esta dissertação analisa e compara as estratégias de compensação série-série (SS) e série-paralela (SP) sob diversos pontos de vista, identificando pontos de operação relevantes nos quais o sistema atua como uma fonte de corrente ou de tensão em malha aberta, modela os elementos que constituem um sistema de transferência indutiva de potência para alcançar à eficiência requisitada. Adicionalmente este trabalho lista os impactos na fonte e na carga quando do desvio das condições nominais de operação e dá diretrizes que permitem escolher os elementos de um sistema IPT. Na sequência esta dissertação propõe as diretrizes para a construção do transformador com valores predefinidos de fator de qualidade, indutâncias próprias e fator de acoplamento. Por fim, o presente trabalho dimensiona e confecciona alguns sistemas IPT a partir de uma lista de especificações, usando uma metodologia de projeto baseada em fórmulas aproximadas e a valida experimentalmente. / Recently Wireless Power Transfer (WPT) is widely studied in order to efficiently feed many different kinds of loads using specific techniques, such as Capacitive Power Transfer (CPT) and Inductive Power Transfer (IPT). IPT system relies on large air gap and loosely coupled transformer which will be studied in this work. Due to the large separation between the primary and secondary coils, the absence of a magnetic core, or the presence of split cores the transformer presents large leakage inductances, resulting in poor voltage regulation against load variation. Moreover, the low magnetizing inductance results in high magnetizing currents, reducing the overall efficiency. In order to improve the WPT performance, capacitive compensation techniques are applied in both sides of the transformer. Series compensation is commonly used at the primary side of the WPT transformer while Series or Parallel compensation is eligible to the secondary side. In addition, the loosely coupled transformer must be designed, in spite of the complex relationship between the various electrical and geometrical parameters of the coils that complicates the transformer construction and its optimization. This work compares Series-Series and Series-Parallel compensation strategies based on a simple approach, comprehensively highlighting the pro and cons of each one. Also the open loop operation in voltage source and current source modes, and the effect of the gap length for both compensation strategies are discussed. Moreover, the elements that constitute an inductive power transfer system are modeled in order to achieve the required efficiency. This research also proposes some guidance to build the transformer with high figure-of-merit and coupling. Finally, the present work designs and builds few IPT systems that satisfies a set of specifications, based on a simplified design procedure. The proposed design methodology is experimentally validated.

Recentemente os sistemas de transferência de energia sem fio WPT (do inglês Wireless Power Transfer) têm sido amplamente estudados com o propósito de alimentar eficientemente diversos tipos de cargas através de técnicas específicas, dentre elas destaca-se a transferência capacitiva de potência CPT (do inglês Capacitive Power Transfer) e a transferência indutiva de potência IPT (do inglês Inductive Power Transfer), sendo esta última objeto deste estudo. Em um sistema de transferência indutiva de potência a carga é alimentada através de um transformador fracamente acoplado. Em função do elevado espaçamento entre as bobinas primária e secundária, da ausência de núcleo magnético, ou o emprego do núcleos divididos e separados por um grande entreferro, o transformador apresenta alta reatância de dispersão e baixa reatância de magnetização, o que resulta em elevadas correntes, baixa eficiência e regulação da tensão ruim quando houver variação da carga. Com o intuito de aumentar a eficiência e melhorar a regulação de tensão (ou corrente) são aplicadas compensações capacitivas em ambos os lados do transformador, elevando o número de elementos reativos, o que dificulta a compreensão do seu comportamento. Adicionalmente, as diversas configurações geométricas possíveis para a construção das bobinas dificultam a otimização do projeto de transferência indutiva de potência. Esta dissertação analisa e compara as estratégias de compensação série-série (SS) e série-paralela (SP) sob diversos pontos de vista, identificando pontos de operação relevantes nos quais o sistema atua como uma fonte de corrente ou de tensão em malha aberta, modela os elementos que constituem um sistema de transferência indutiva de potência para alcançar à eficiência requisitada. Adicionalmente este trabalho lista os impactos na fonte e na carga quando do desvio das condições nominais de operação e dá diretrizes que permitem escolher os elementos de um sistema IPT. Na sequência esta dissertação propõe as diretrizes para a construção do transformador com valores predefinidos de fator de qualidade, indutâncias próprias e fator de acoplamento. Por fim, o presente trabalho dimensiona e confecciona alguns sistemas IPT a partir de uma lista de especificações, usando uma metodologia de projeto baseada em fórmulas aproximadas e a valida experimentalmente. / Recently Wireless Power Transfer (WPT) is widely studied in order to efficiently feed many different kinds of loads using specific techniques, such as Capacitive Power Transfer (CPT) and Inductive Power Transfer (IPT). IPT system relies on large air gap and loosely coupled transformer which will be studied in this work. Due to the large separation between the primary and secondary coils, the absence of a magnetic core, or the presence of split cores the transformer presents large leakage inductances, resulting in poor voltage regulation against load variation. Moreover, the low magnetizing inductance results in high magnetizing currents, reducing the overall efficiency. In order to improve the WPT performance, capacitive compensation techniques are applied in both sides of the transformer. Series compensation is commonly used at the primary side of the WPT transformer while Series or Parallel compensation is eligible to the secondary side. In addition, the loosely coupled transformer must be designed, in spite of the complex relationship between the various electrical and geometrical parameters of the coils that complicates the transformer construction and its optimization. This work compares Series-Series and Series-Parallel compensation strategies based on a simple approach, comprehensively highlighting the pro and cons of each one. Also the open loop operation in voltage source and current source modes, and the effect of the gap length for both compensation strategies are discussed. Moreover, the elements that constitute an inductive power transfer system are modeled in order to achieve the required efficiency. This research also proposes some guidance to build the transformer with high figure-of-merit and coupling. Finally, the present work designs and builds few IPT systems that satisfies a set of specifications, based on a simplified design procedure. The proposed design methodology is experimentally validated.