Les amplificateurs de puissance, éléments constitutifs essentiels de tout système de télécommunication, vont jouer un rôle capital dans le développement des futurs systèmes de communication. Aujourd'hui l'amélioration des amplificateurs de puissance nécessite un progrès technologique au niveau du composant lui même mais doit aussi tenir compte d'une approche plus globale. En particulier, le progrès dans les traitements numériques permet aujourd'hui de corriger en amont certaines distorsions qui seront générées en aval de la chaîne de communication. La pré-distorsion numérique est une technique de correction des amplificateurs de puissance qui connaît un intérêt grandissant de par son intégration complètement numérique et par les gains en linéarité et en consommation. Cette technique nécessite une voie de retour dont un élément critique est le convertisseur analogique-numérique. Ce composant doit répondre à des contraintes de résolution, de bande passante et de linéarité élevées. Dans cette thèse, nous proposons une nouvelle architecture de convertisseur analogique-numérique à base de modulateurs Sigma-Delta passe-bande. Cette architecture tire partie du fonctionnement passe bande des modulateurs que nous faisons travailler en parallèle, chacun centré sur différentes fréquences, mais aussi d'un agencement en cascade particulier pour éliminer le signal utile, qui est de forte puissance, dans le but de diminuer les contraintes de dynamique.La conception haut niveau et les simulations ont été menées pour des systèmes à temps discret et aussi à temps continu et a nécessité le développement d'outils adaptés de simulation se basant sur la boîte à outils Delta Sigma Toolbox de Richard Schreier / Power amplifiers, which are essential elements of any communication system, will play a crucial role in the development of future communication systems. Today improving power amplifiers requires technological advances at the circuit device level, but one also must consider a more global approach. In particular, advances in digital processing can now correct in the early stage of the communication chain some distortions that are generated downstream in the chain. Digital pre-distortion is a correction technique for power amplifiers that has a growing interest because of its completely digital implementation and of its gains in linearity and energy consumption. This technique requires a feedback path where the analog-to-digital converter is a critical element. This component must satisfy the constraints of high resolution , wide bandwidth, and high linearity. In this thesis, we propose a new architecture of analog-to-digital converter based on bandpass Delta-Sigma modulators. This architecture takes advantage of operating bandpass modulators that are designed to work in parallel, each focusing on different frequencies, but also of a particular cascading arrangement to eliminate the useful signal, which has a high power, in order to reduce dynamics constraints. High-level design and simulations were carried out for discrete time and continuous time systems and also required the development of appropriate simulation tools.

Cette thèse porte sur la conception et la réalisation de convertisseurs analogique/numérique (ADC) haute résolution dans le domaine de l’imagerie spatiale en technologie 0.18 μm.Un imageur CMOS est un système destiné à acquérir des informations lumineuses et les convertir en données numériques afin que cellesci soient traitées. Ce système est composé d’une matrice de pixels, d’ADC, de registres et de blocs de signaux de commande afin de rendre toutes ces données disponibles. Avec la taille grandissante de la matrice de pixels et la cadence d’image par seconde croissante, l’ADC doit réaliser de plus en plus de conversions en moins de temps et est donc devenu l’un des « bottleneck » les plus importants dans les systèmes d’imagerie. Une solution adaptée a donc été le développement d’ADC colonne situé en bout de colonnes de pixels afin de réaliser des conversions en parallèles et c’est ce sujet qui va m’intéresser.Dans une première partie, n’ayant pas de contraintes sur l’architecture d’ADC à utiliser, une étude de l’état de l’art des ADC pour l’imagerie est réalisée ainsi que les spécifications visées pour notre application. Une architecture sigma-delta incrémental à deux étapes semble la plus prometteuse et va être développée. Ensuite, une étude théorique de l’ADC choisi, et plus particulièrement du modulateur sigma-delta à utiliser est effectuée, afin notamment de déterminer l’ordre de ce modulateur, mais également le nombre de cycles de cette conversions. Une fois les paramètres de modélisation définis, un schéma transistor est réalisé au niveau transistor, avec une particularité au niveau de l’amplificateur utilisé. En effet, afin de gagner en surface qui est l’un des points importants dans les systèmes d’imagerie, un inverseur est utilisé. Une étude de cette inverseur, afin de choisir le plus adapté à notre besoin est effectuée avec des simulations montecarlo et aux « corners ». Pour finir, un routage global de l’ADC est réalisé afin de pouvoir comparer ces performances à l’état de l’art. / This thesis deals with the conception and design of high resolution analog-to-digital converters (ADC) for CMOS image sensor (CIS) applications with the 0.18 μm technology. A CIS is a system able to convert light to digital data to be processed. This system includes a pixel array, ADCs, registers and a set of clocks to acquire and transport the data. At the beginning, a single ADC was used for the whole matrix of pixels, converting the pixel value in a sequential way. With the growing size of the pixel array and the increasing frame rate, the ADC became one of the bottleneck of these system. A solution was found to use column ADC, located at the bottom of each column in order to parallelize the conversions. These column ADC are going to be my point of interest in this thesis.First of all, a state of the art of the ADC for CIS is realized in order to determine the best architecture to use. A two-step incremental sigma-delta is chosen and investigated. A theoretical analysis is done, especially on the modulator in order to determine the order of this modulator and the oversampling ratio of the conversion. Then a schematic is realized, with a special feature on the amplifier. Indeed, an inverter is used as amplifier in order to reduce the size of the ADC. A montecarlo and corner studies are then realized on the ADC, a layout is proposed and the ADC is compared to the state of the art of the ADC for CIS.

Bacteria, the most dominant organisms on Earth, are an everyday presence in our lives. Symbiotic bacteria, which are present in the digestive tract of animals, usually have a beneficial effect on the body. On the opposite side of the spectrum are pathogenic species that cause more or less serious diseases around the world. In order to fight pathogens effectively, it is necessary to learn as much as possible about the molecular mechanisms by which bacteria respond to their environment, and also about the types of communication within bacterial populations that allow them to react to environmental changes as "multicellular" organisms. This Thesis consists of two main parts. In the first part, selected aspects of bacterial gene expression are characterized, using Bacillus subtilis and Mycobacterium smegmatis as model organisms. DNA-dependent RNA polymerase (RNAP) is the enzyme that is responsible for transcription of DNA into RNA, and thus plays a key role in gene expression. This Thesis deals with the structure of bacterial RNAP and important auxiliary factors (proteins and RNA) that associate with this enzyme and modulate its function. In the second part, the focus is on cell-to-cell communication, revealing which factors/mechanisms, including gene expression, affect this process in B. subtilis....

Lean Six Sigma is an approach focused on improving quality, reducing variation and eliminating waste in an organization. The concept of combining the principles and tools of Lean Enterprise and Six Sigma has occurred in the literature over the last several years. The majority of Lean Six Sigma applications have been in private industry, focusing mostly on manufacturing applications. The literature has not provided a framework for implementing Lean Six Sigma programs applied to local government. This research provides a framework roadmap for implementing Lean Six Sigma in local government. The Service Improvement for Transaction-based Entities Lean Six Sigma Framework Roadmap (SITE MAP) identifies the activities, principles, tools, and important component factors to implement Lean Six Sigma. The framework provides a synergistic approach to integrating the concepts and tools of Lean Enterprise and Six Sigma using the DMAIC (Define-Measure-Analyze-Improve-Control) problem solving approach. A case study was used to validate the framework. Lean Six Sigma was successfully applied in a 7,000-citizen municipality to reduce the cycle time of the financial administrative processes in the Finance Department of the city government.

Many organizations are struggling to improve customer-focused quality in today's highly competitive domestic and global markets. At the same time, these organizations have failed to implement the Six Sigma methodology into their daily control and strategic planning processes. Six Sigma deployment failures have been categorized as coming from many sources, both management related and person related. Some of the key management related Six Sigma project failures have been identified and discussed in this research work. For continuous improvement to truly take root, organizations must realize that just successfully applying quality tools on any process will not necessarily provide dramatic results, unless the concepts of policy management and deployment are institutionalized. A model called "Six Sigma Policy Deployment" was developed and has been proposed which may help mitigate Six Sigma project failures that are presently attributed to management and organizational issues. By integrating Policy Deployment, the Six Sigma DMAIC (Define-Measure-Analyze-Improve-Control) problem solving approach, and the classic PDCA (Plan-Do-Check-Act) Cycle, the potential for breakthrough improvements in any organization can be enhanced. The model was contrasted against a list of 30 sources of failure in typical Six Sigma projects in order to validate its applicability to mitigate these failures. Furthermore these failures were matched with the work of recent quality theorists in order to validate their occurrence and relevance. A case study section is presented to illustrate FPL's Quality Improvement Program and the Six Sigma Lifecycle, which are bases for the new model. This section also highlights how the use of the proposed Six Sigma Policy Deployment model could help to mitigate potential Six Sigma project failures.

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A continuous improvement project (CIP) is a structured improvement project using a team of people "typically representing different departments or units in the organization" working to improve a process or work area over a relatively short period of time, such as a few days or up to several months. A CIP may use different improvement methodologies and tools, and may thus be defined according to the improvement approach. For instance, an organization adopting Lean as an improvement approach is likely to have CIPs implementing Lean tools, such as 5S or value stream mapping. These projects may be referred to as Lean projects in general, although they may also represent accelerated improvement projects such as Kaizen events, Kaizen blitz, or rapid improvement projects. Alternatively, an organization utilizing Six Sigma as an improvement approach may have Six Sigma projects that use the Define-Measure-Analyze-Improve-Control (DMAIC) process and statistical tools. Some organizations adopt an integrated improvement approach, such as Lean Six Sigma, and therefore may have CIPs with an even broader set of tools from which to choose. Lastly, many organizations may have an improvement approach not characterized by any single set of improvement processes and tools, and thus, may be thought of generally as process improvement, or quality improvement, projects using a traditional methodology as plan-do-study/check-act (PDSA or PDCA). In this dissertation, all of these types of improvement projects are referred as CIPs. Since the 1980s, hospitals have been using CIPs to address some of the problems in hospitals, such as quality in healthcare delivery, internal process efficiency, communication and coordination, and the cost of services. Some hospitals have achieved significant improvements, such as reducing the turnaround time for clinical laboratory results by 60 percent and reducing instrumentation decontaminations and sterilization cycle time by 70 percent. However, as with many other companies, hospitals often experience difficulty achieving their desired level of improvements with CIPs. Therefore, the purpose of this dissertation is to identify the critical success factors (CSFs) related to CIP success. In order to achieve this goal, five objectives were achieved: creating a methodology to assess the maturity or evolution of a research field (manuscript #1), identifying a comprehensive list of CSFs for CIPs (manuscript #2), assessing the maturity of the published literature on CIPs in hospitals (manuscript #3), identifying the most important factors related to CIPs in hospitals (manuscript #4) , and conducting an empirical investigation to define the CSFs for CIPs in hospital settings (manuscript #5 and #6). This investigation was conducted in three phases: research framing, variable reduction, and model development and testing. During these phases, the researcher used the following methodologies and data collection tools: systematic literature review, maturity framework (developed as part of this dissertation), expert study, retrospective survey questionnaire, exploratory factor analysis, partial-least squares structural equation modeling, and regression modeling. A maturity framework with nine dimensions was created (manuscript #1) and applied in order to identify a list of 53 factors related to CIP in general, involving any organization (manuscript #2). Additionally, the maturity framework was used to assess the literature available on CIPs in hospitals, considering only the authorship characteristic dimension (manuscript #3). Considering the frequency of new authors per year, the relative new integration of research groups, and the limited set of predominant authors, the research field, or area, of CIPs in hospitals is one with opportunities for improving maturity. Using the systematic literature review from manuscript #3, the list of 53 factors, and the list of predominant authors, a review of the literature was conducted, along with an expert study to more fully characterize the importance of various factors (manuscript #4). A conclusion from this particular work was that it is not possible to reduce the list of 53 factors based on these results, thus, a field study using the complete comprehensive list of factors was determined to have stronger practical implications. A field study was conducted to identify factors most related to CIP perceived success (manuscript #5) and CIP goal achievement (manuscript #6). The final results and practical implications of this dissertation consist in the identification of the following CSFs for CIP success in hospitals: Goal Characteristics, Organizational Processes, Improvement Processes, and Team Operation. These CSFs include several specific factors that, to the researcher's knowledge, have not been previously studied in empirical investigations: goal development process, organizational policies and procedures, CIP progress reporting, and CIP technical documentation. Practitioners involved with CIPs, such as CIP leaders, facilitators, stakeholders/customers, and continuous improvement managers/leaders, can utilize these results to increase the likelihood of success by considering these factors in planning and conducting CIPs. / Ph. D.

This thesis is devoted to a thorough study of chiral rings in two-dimensional (0,2) theories. We first discuss properties of chiral operators in general two-dimensional (0,2) nonlinear sigma models, both in theories twistable to the A/2 or B/2 model, as well as in non-twistable theories. As a special case, we study the quantum sheaf cohomology of Grassmannians as a deformation of the usual quantum cohomology. The deformation corresponds to a (0,2) deformation of the nonabelian gauged linear sigma model whose geometric phase is associated with the Grassmannian. Combined with the classical result, the quantum ring structure is derived from the one-loop effective potential. Supersymmetric localization is also applicable in this case, which proves to be efficient in computing A/2 correlation functions. We then compute chiral operators in general (0,2) nonlinear sigma models, and apply them to the Gadde-Gukov-Putrov triality proposal, which says that certain triples of (0,2) GLSMs should RG flow to nontrivial IR fixed points. As another application, we extend previous works to construct (0,2) Toda-like mirrors to the sigma model engineering Grassmannians. / Ph. D. / This thesis studies a mathematical concept called the chiral ring, which emerges from string theory. String theory is a conjectured theory that potentially unifies the existing fundamental physical laws. It has connections with many branches of mathematics, especially geometry. Spacetime is ten-dimensional in string theory, of which four dimensions are visible, and the other six are hidden at ordinary energy levels. The chiral ring encodes many geometric properties of the hidden part of spacetime. These properties can in turn affect the visible universe even at low energies. Research on chiral rings has primarily focused on a special class of geometries which have large symmetries and so are easier to handle. In order to tackle more general scenarios, we analyze the chiral rings corresponding to theories with only half the symmetry and give several new results and applications.

Cada vez mais presentes no ambiente industrial, as metodologias de melhoria contínua estruturam e sistematizam a implantação e a aplicação de técnicas, ferramentas e práticas de melhoria dos processos, que permitem reduzir o lead time, aumentar a satisfação do cliente, diminuir a variabilidade dos processos e elevar a qualidade do produto. Neste contexto, o objetivo deste trabalho é, com o auxílio de um framework teórico, estudar o uso de Lean Manufacturing e Six Sigma em um caso real pertencente ao parque industrial nacional. Dessa forma, optou-se por realizar um estudo de caso em uma empresa do ramo automobilístico, visto a relação do setor com a melhoria contínua. A companhia já utilizava as técnicas e ferramentas há mais de uma década e, além de mostrar a sua abordagem com relação à melhoria contínua de forma geral, apresentou dois casos para comparação das soluções encontradas para seu próprio aperfeiçoamento. Foi observado que a empresa encontra-se em um estágio intermediário-avançado dentro do framework construído e foi ressaltado que o Kaizen é a principal forma de melhoria usada. / Increasingly present in industrial environment, the continuous improvement methodologies structured and systematized the implementation and employment of techniques, tools and practices of process improvement, which allow reducing lead time, enhancing customer satisfaction, decreasing process variability and raising product quality. In this context, supported by a framework, what this study aims at is to review the use of Lean Manufacturing and Six Sigma in a real case belonging to the national industrial park. Hence, a case study was chosen in a company from the automotive industry, insofar as its relationship with continuous improvement. The company had already been using the techniques and tools for over a decade and it was provided an overview of its approach and, in addition, two cases to have their solution compared. It was observed that the company stands in an upper intermediate stage according to the developed framework and it was also highlighted that Kaizen is the main improvement means used.