Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

by Lam Ho Cheung, Andrew. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 1-5 (3rd gp.)). / ABSTRACT --- p.I1-3 / ACKNOWLEDGEMENTS --- p.II / TABLE OF CONTENTS --- p.III1-2 / Chapter CHAPTER ONE - --- INTRODUCTION / Chapter 1.1 --- The Problem --- p.1 / Chapter 1.2 --- The purpose of the thesis --- p.5 / Chapter CHAPTER TWO - --- PSYCHIATRIC OUTPATIENT SERVICE PROVISION / Chapter 2.1 --- Provision of psychiatric outpatient provision --- p.6 / Chapter 2.2 --- The problem of pattern of consultation --- p.13 / Chapter CHAPTER THREE- --- OBJECTIVES AND HYPOTHESIS SETTING / Chapter 3.1 --- Objectives --- p.30 / Chapter 3.2 --- Definition of essential terms --- p.30 / Chapter 3.3 --- Hypothesis setting --- p.32 / Chapter CHAPTER FOUR - --- METHOD / Chapter 4.1 --- Research design and Data collection method --- p.36 / Chapter 4.2 --- Recording schedule design --- p.37 / Chapter 4.3 --- Setting --- p.39 / Chapter 4.4 --- Subjects --- p.40 / Chapter 4.5 --- Data Collection and Processing --- p.40 / Chapter 4.6 --- Data analysis --- p.43 / Chapter CHAPTER FIVE - --- DESCRIPTIVE FINDINGS / Chapter 5.1 --- The overall pattern of consultations --- p.45 / Chapter 5.2 --- Diagnostic group of sex and age group --- p.53 / Chapter CHAPTER SIX - --- FACTORS ASSOCIATED WITH DROP-OUTS OF PATIENTS / Chapter 6.1 --- Background of the drop-outs and the non-drop-outs group --- p.55 / Chapter 6.2 --- Univariate analysis of relationship between various variables and drop-outs --- p.55 / Chapter 6.3 --- Multiple logistic regression model of relationship between drop-outs and various variables --- p.58 / Chapter CHAPTER SEVEN - --- FACTORS ASSOCIATED WITH PROLONGED & CONTINUED ATTENDANCE / Chapter 7.1 --- Background of the treated & discharged group and prolonged & continued attendance group --- p.62 / Chapter 7.2 --- Univariate analysis of relationship between various variables and prolonged & continued attendance --- p.62 / Chapter 7.3 --- Multiple logistic regression model of relationship between prolonged & continued attendance and various variables --- p.65 / Chapter CHAPTER EIGHT - --- DISCUSSION / Chapter 8.1 --- The overall pattern of consultations --- p.69 / Chapter 8.2 --- Factors associated with the risk of drop-outs --- p.76 / Chapter 8.3 --- Factors associated with the prolonged & continued attendance --- p.80 / Chapter 8.4 --- Implications to service delivery --- p.85 / Chapter 8.5 --- Limitations of this thesis --- p.86 / Chapter CHAPTER NINE - --- CONCLUSION AND RECOMMENDATIONS / Chapter 9.1 --- Conclusion --- p.90 / Chapter 9.2 --- Recommendations --- p.92 / Chapter 9.3 --- Suggestion for future work --- p.93 / BIBLIOGRAPHY / APPENDIX I - TABLE / APPENDIX II- SAMPLE RECORDING SCHEDULE

In this thesis we study Kähler groups and their connections to Geometric Group Theory. This work presents substantial progress on three central questions in the field: (1) Which subgroups of direct products of surface groups are Kähler? (2) Which Kähler groups admit a classifying space with finite (n-1)-skeleton but no classifying space with finitely many n-cells? (3) Is it possible to give explicit finite presentations for any of the groups constructed in response to Question 2? Question 1 was raised by Delzant and Gromov. Question 2 is intimately related to Question 1: the non-trivial examples of Kähler subgroups of direct products of surface groups never admit a classifying space with finite skeleton. The only known source of non-trivial examples for Questions 1 and 2 are fundamental groups of fibres of holomorphic maps from a direct product of closed surfaces onto an elliptic curve; the first such construction is due to Dimca, Papadima and Suciu. Question 3 was posed by Suciu in the context of these examples. In this thesis we: provide the first constraints on Kähler subdirect products of surface groups (<strong>Theorem 7.3.1</strong>); develop new construction methods for Kähler groups from maps onto higher-dimensional complex tori (<strong>Section 6.1</strong>); apply these methods to obtain irreducible examples of Kähler subgroups of direct products of surface groups which arise from maps onto higher-dimensional tori and use them to show that our conditions in Theorem 7.3.1 are minimal (<strong>Theorem A</strong>); apply our construction methods to produce irreducible examples of Kähler groups that (i) have a classifying space with finite (n-1)-skeleton but no classifying space with finite n-skeleton and (ii) do not have a subgroup of finite index which embeds in a direct product of surface groups (<strong>Theorem 8.3.1</strong>); provide a new proof of Biswas, Mj and Pancholi's generalisation of Dimca, Papadima and Suciu's construction to more general maps onto elliptic curves (<strong>Theorem 4.3.2</strong>) and introduce invariants that distinguish many of the groups obtained from this construction (<strong>Theorem 4.6.2</strong>); and, construct explicit finite presentations for Dimca, Papadima and Suciu's groups thereby answering Question 3 (<strong>Theorem 5.4.4)</strong>).

Thesis (Ph.D. (History)) -- University of Limpopo, 2018 / The purpose of this study was to investigate the genealogy and migration of the va ka Valoyi people of Limpopo Province, South Africa. Qualitative, narrative research was used to study the oral history of the va ka Valoyi to determine the origin, migration routes and the genealogy of the 20 (twenty) communities of the va ka Valoyi in Limpopo. Data collection was done using semi-structured questionnaires. An initial list of 20 (twenty) respondents was drawn and through Snowball Sampling, the list was increased as per referrals made by the 20 (twenty) respondents during their individual interviews. At the end of the research, 67 (sixty-seven) respondents had been interviewed and secondary sources also consulted. The study has reconstructed the history of the va ka Valoyi, which had not been written before and managed to fill some gaps in the history of their associate groups that historians had not been able to fill in the past. The findings revealed that all the 20 (twenty) communities of the va ka Valoyi in Limpopo are related and identified the various relationships among them. It also revealed how the va ka Valoyi are related to ancient dynasties of the Munhumutapa, Changamire and Torwa and how they reached the Limpopo Province. KEY CONCEPTS Genealogy; Migration; va ka Valoyi; Arrival in Limpopo Province; Oral history.

Les transistors à haute mobilité électronique (HEMTs) à base de nitrure de gallium constituent une filière prometteuse pour l’amplification de puissance hyperfréquence pour les applications en bande millimétrique. Les propriétés remarquables du GaN, tels que le champ de claquage , la vitesse de saturation et la densité des électrons élevés sont à l’origine des performances exceptionnelles obtenues avec les dispositifs à base de GaN. Les travaux de thèse ont été réalisés au sein du groupe Composants et Dispositifs Micro-ondes de Puissance à l’IEMN. Ce travail relate la fabrication et la caractérisation de dispositifs de type HEMT de la filière GaN pour des applications de puissance hyperfréquence. La première partie de ce travail expose les phénomènes physiques mis en jeu dans les hétérostructures à base de GaN. La suite porte sur l’optimisation des procédés technologiques ayant comme point de mire la montée en fréquence ainsi qu’en puissance hyperfréquence. Un travail a été mené en vue de la réduction de la longueur du pied de grille permettant d’atteindre des longueurs minimales de l’ordre de 60nm. De plus, des analyses sont effectuées afin d’étudier les principales limitations inhérentes aux composants HEMTs. Le dernier chapitre présente l’ensemble des caractérisations en régimes statique et hyperfréquence sur des structures HEMTs fabriquées dans le cadre de ce travail. Il en ressort notamment un résultat en terme de densité de puissance à 40GHz, à ce jour à l’état de l’art, relatif à un HEMT de topologie 2x50x0.075µm2. Celui-ci ayant permis d’obtenir une densité de puissance de 2.7W/mm associée à un gain linéaire de 6.5dB et un rendement en puissance ajoutée de 12.5%. / Gallium Nitride (GaN) based High Electron Mobility Transistors (HEMTs) have emerged as the best candidate for high temperature, high voltage and high power operation in millimeter-wave range. The unique combination of high breakdown field, high electron velocity, and large sheet electron densities of III-N material permits outstanding performance. The work was performed within IEMN laboratory in Microwave Power Devices group. It relates the fabrication and the characterization of GaN HEMT devices for microwave power applications. The first part exposes the physical and electrical properties of gallium nitride as well as a review concerning the state of the art in terms of output power density related to GaN HEMTs. The second chapter deals with the technological processes with a particular attention on the process optimization regarding the ohmic contact and the T-gate technology. Despite outstanding properties, the HEMT performance remains inherently limited by physical and electrical parasitic phenomena. Thus, the third chapter presents the whole studies performed in other to understand these limitation effects (losses, traps, thermal effect). In the last chapter DC, RF, pulsed and large signal measurements are reported for HEMTs based on different heterostructures. In particular, the capability of AlGaN/GaN transistors on Si(111) substrate grown by MBE is demonstrated for high frequency microwave power applications at 40GHz with a continuous wave output power density of 2.7W/mm associated with a power added efficiency of 12.5% and a linear gain of 6.5dB corresponding to the highest saturated power density ever reported on Si(111) substrate to date.

Dans le cadre de cette thèse nous nous intéressons à la liaison d'un terminal utilisateur vers un satellite géostationnaire pour les futurs systèmes d'applications multimédia en bande Ka. Le but est de concevoir une forme d'onde qui permet de s'adapter aux conditions de propagation. L'adaptation des performances en spectre et en puissance de la forme d'onde, notamment dans un contexte avec une forte fluctuation du niveau du signal, comme celui du canal satellite en bande Ka, permet à la fois d'augmenter la capacité et d'améliorer la disponibilité du système. Dans ces travaux, les formes d'onde basées sur les modulations CPM (Continuous Phase Modulation) ont été adoptées. L'enveloppe constante, les différents paramètres ayant un impact sur les performances de la forme d'onde, ainsi que les bonnes performances en puissance lors d'un processus de décodage itératif sont les principales motivations de notre choix. Concernant l'adaptativité nous montrons qu'une forme d'onde CPM basée sur la variation de l'indice de modulation (et éventuellement la réponse en fréquence) au sein d'une famille d'indices ayant un même dénominateur est une solution particulièrement attractive. Une telle solution ne nécessite pas une très grande complexité lors d'un passage d'un mode de transmission à un autre. Elle nécessite essentiellement le changement des coefficients des filtres adaptés. Cette technique permet aussi d'obtenir une marge de performance assez importante vu que l'indice de modulation est le paramètre qui affecte le plus les performances de la CPM. La CPM octale 2RC est un schéma particulièrement attractif d'un point de vue performance.

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