Les hélicoptères sont le siège de comportements dynamiques difficiles à maîtriser et récurrents en phase de conception. Ces comportements sont essentiellement liés à des couplages mal maîtrisés entre certains sous-systèmes. Un état de l'art sur les pratiques de modélisation existantes met en évidence un manque de prise en compte des interactions énergétiques entre sous-systèmes, rendant difficile l'analyse et la maîtrise de ces phénomènes et conduisant à des solutions ponctuelles, sans capitalisation possible des méthodes mises en œuvre. Ces travaux offrent une introduction à une approche de représentation multiphysique et multiniveau, complémentaire aux approches existantes, offrant une vision énergétique et structurelle pour la maîtrise de la dynamique des systèmes tels que les hélicoptères. Une réflexion sur les outils de représentation existants a conduit au choix du bond graph (BG), du multibond graph (MBG) et de la Représentation Energétique Macroscopique (REM) en tant qu'outils complémentaires pour la modélisation et la commande des systèmes multiphysiques multicorps. Une analyse énergétique d'hélicoptère a conduit à la proposition d'une description macroscopique basée sur le MBG à mots, complétée par deux autres niveaux détaillant le modèle MBG du sous-système rotor-fuselage. Les hypothèses de modélisation sont choisies de manière à reproduire les conditions d'apparition du phénomène de résonance air, phénomène de couplage connu sur les hélicoptères. Cette étude met en évidence le potentiel des représentations énergétiques en application aux hélicoptères et ouvre de nombreuses perspectives, tant pour l'analyse des appareils existants que pour la conception d'aéronefs innovants.

Alle in dieser Dissertation gemachten Analysen fokussieren auf einen zentralen Element für die Entstehung und die Entwicklung der Pfingstbewegung. Es handelt sich dabei um das Konzept, dass sich religiöse Erlösung auf die Erfahrung des sozialen Aufstiegs gegründet ist, insbesondere im Sinne der Integration unterintegrierter sozialen Gruppen in die Gesellschaft. Diese in den USA enstandende neue Religion befriegt vor allem die religiösen und sozialen Bedürfnisse derjenigen Bevolkerungsgruppen, die neu in der urbanen Welt der großen nordamerikanischen Städten angekommen waren. Es geht dabei also um diejenigen sozialen Schichten, die in der Peripherie dieser grossen Städte lebeten und die sozial, wirtschaftlichund ethnisch aus der Gesellschaft ausgeschlossen wurden. Im Anschluss daran analysieren wir auch, wie die gleichen sozialen und religiösen Bedürfnisse die Grundlagen für die Entwicklung der Pfingstbewegung in Lateinamerika darstellen – insbesondere in Brasilien. In diesem Land findet eine grosse Menge exkludierter Individuen, die meistens auch Bewohner städtischer Peripherie sind (was ihren modernen Charakter beweist), im Pentekostalismus das Versprechen einer Lösung für ihre Probleme, vor allem für die Sehensucht nach Integration in eine soziale Welt, an der sie vorher nicht teilnahmen. Dieses Integrationsversprechen hängt direkt mit der normativen Erwartung des sozialen Aufstiegs zusammen. Aus disem Bild kann man den Schluss ziehen, dass sich der Pentekostalismus als religiöses Phänomen dadurch auszeichnet, dass er die Versprechen der Moderne für die von der modernen Gesellschaften vergessenen Individuen aktualisiert. Mittes seiner religiösen Narrative verleiht der Petenkostalismus der Idee des sozialen Aufstiegs und damit auch der Hoffnung sozialer Inklusion exkludierter Individuen eine neue Kraft. Der Pentekostalismus nimmt auf diese Weise die Form einer christlichen Religion der Schwarzen, Mulatos, Armen und aller anderen Individuen an, deren Integration in die moderne Gesellschaft als problematisch erscheint. / All the analyses we have developed throughout this dissertation point to a central element in the emergence and development of Pentecostalism, i.e., its raw material – the promise of religious salvation – is based on the idea of social ascension, particularly the ascension related to the integration of sub-integrated social groups to the dynamics of society. The new religion that arose in the USA focused on the needs and social dramas that were specific of the newly arrived to the urban world of the large North-American cities, those who inhabited the periphery of these cities, those that were socially, economically, and ethnically excluded from the core of society. We also analyzed how the same social drama was the basis for the development of Pentecostalism in Latin America and, especially, in Brazil. In this country, a great mass of excluded individuals, also residents of urban peripheries (which proves the non-traditional and modern characteristic of these sectors), found in Pentecostalism the promises of answers to their dramas, mainly the anxiety to become integrated to a world in which they did not belong before. Such integration was embedded in the promise present in the modernity of social ascension. This scenario leads us to the conclusion that Pentecostalism was a religious discourse capable of taking the main promise of modernity to social groups or classes “forgotten” by modern society. Through a religious discourse, Pentecostalism fulfilled the notions of social mobility, and its consequent idea of individual ascension to the mass of people not yet fully integrated to the modern world, but living in it. Following, it became the Christian religion of blacks and mestizos, of the poor and all the others who felt out of place in that world. So the Pentecostalism became a religion of periphery par excellence.

Customer lifetime value (CLV) is a forecasted expectation of the future value of a customer to the firm. There are two customer behavioral components of CLV that represent a particular modeling challenge: 1) how many transactions we expect from a customer in the future, and 2) how likely it is the customer remains active. Existing CLV models like the Pareto/NBD are valuable managerial tools because they are able to provide forward-looking estimates of transaction patterns and customer churn when the event of a customer leaving is unobservable, which is typical for most noncontractual goods and services. The CLV model literature has for the most part maintained its original assumption that the number of customer transactions follows a stable transaction process. Yet there are many categories of noncontractual goods and services where the stable transaction rate assumption is violated, particularly seasonal purchase patterns. CLV model estimates are further biased when there is an excess of customers with no repeat transactions. To address these modeling challenges, within this thesis I develop a generalized CLV modeling framework that combines three elements necessary to reduce bias in model estimates: 1) the incorporation of time-varying covariates to model data with transaction rates that change over time, 2) a zero-inflated model specification for customers with no repeat transactions, and 3) generalizes to different transaction process distributions to better fit diverse customer transaction patterns. This CLV modeling framework provides firms better estimates of the future activity of their customers, a critical CRM application.

Three series of studies were conducted to quantify the effectiveness of dietary incorporation of b-1,3-glucan (BG) from Schizophyllum commune in enhancing the immunity and resistance of grass prawn Penaeus monodon to vibriosis and white spot syndrome virus (WSSV) infections. In the first series of studies, three experiments were conducted to evaluate the effectiveness of dietary b-1,3-glucan on shrimp growth and resistance to vibriosis. Weight gain, survival and feed efficiency of juvenile shrimp (0.5 ¡Ó 0.1 g) were not significantly different (P>0.05) after being fed the diets containing BG 0, 0.2, 2, 10 g/kg diet for 18 weeks. Subadult shrimp (20.4 ¡Ó 2.1 g) fed the diet containing of BG 2 g/kg diet for 10 days showed a significantly (P<0.001) enhanced resistance against vibriosis. Postlarvae fed with the BG diet (2 g/kg diet) were more resistant (P<0.001) against starvation and V. harveyi challenges than the postlarvae fed non-BG diet. Additive disease resistance was observed when polyphosphorylated L-ascorbic acid (PAA) was used together with BG. In challenge tests with V. damsela, shrimp fed with PAA (0.2 g/kg diet) + BG (2 g/kg diet) diet for 20 days had a survival rate up to 60%. In the second series of studies, two experiments were conducted to evaluate the effectiveness of dietary b-1,3-glucan on wound healing and immunity in spawners. Dietary supplement of BG reduced the chance of infections, but did not help wound healing as did the supplement of PAA. And regardless of indoor or outdoor rearing, the survival rate of brooder (135 ¡Ó 25 g) fed the BG (2 g/kg diet) diet was higher (P<0.001) than that of the non-BG group. Fed the BG brooders showed enhanced haemocyte phagocytic activity, cell adhesion and superoxide anion production then the control group. Third series of studies evaluated the effectiveness against white spot syndrome virus (WSSV). Six days after being challenged with WSSV, 12.2 % of the BG-treated (2 g/kg diet for 15 days) postlarvae (PL15) and 20 % BG-treated (2 g/kg diet for 20 days) juveniles (5.5 ¡Ó 0.5 g) were still alive; while all non-BG-treated shrimp died. In order to quantify the effectiveness of BG to WSSV, juveniles (6.5 ¡Ó 0.4 g) were fed diets containing graded levels of BG. The results showed that shrimp fed the diet containing BG 10 g/kg for 20 days had the highest (P<0.001) survival rate (42 %) among all groups. Shrimp that received diets supplemented with BG at a dosage >2 g/kg recuperated 9 ~ 12 days after WSSV challenge; while the group fed diets with no or 1 g/kg BG suffered from rapid decrease in total haemocyte count, phagocytic activity, phenoloxidase, O2-, superoxide dismutase (SOD) production and subsequent high mortality. The results in this study showed that b-1,3-glucan is effective in enhancing the phagocytic activity, phenoloxidase, O2- and SOD productions and consequently the resistance of postlarval, juvenile, subadult and brooder P. monodon against vibriosis and viral infections. Since prolonged use of BG, even at optimal dietary levels, decreased the immunity of the shrimp, care therefore must be taken to maximize its effectiveness. A cycle of dietary BG supplement of 2 ~ 10 g/kg diet for 20 days with an intermission of 10 days may serve the purposes.

Silicon carbide (SiC) has higher breakdown field strength than silicon (Si), which enables thinner and more highly doped drift layers compared to Si. Consequently, the power losses can be reduced compared to Si-based power conversion systems. Moreover, SiC allows the power conversion systems to operate at high temperatures up to 250 oC. With such expectations, SiC is considered as the material of choice for modern power semiconductor devices for high efficiencies, high temperatures, and high power densities. Besides the material benefits, the typeof the power device also plays an important role in determining the system performance. Compared to the SiC metal-oxide semiconductor field-effect transistor (MOSFET) and bipolar junction transistor (BJT), the SiC junction field-effect transistor (JFET) is a very promising power switch, being a voltage-controlled device without oxide reliability issues. Its channel iscontrolled by a p-n junction. However, the present JFETs are not optimized yet with regard to on-state resistance, controllability of threshold voltage, and Miller capacitance. In this thesis, the state-of-the-art SiC JFETs are introduced with buried-grid (BG) technology.The buried grid is formed in the channel through epitaxial growth and etching processes. Through simulation studies, the new concepts of normally-on and -off BG JFETs with 1200 V blocking capability are investigated in terms of static and dynamic characteristics. Additionally, two case studies are performed in order to evaluate total losses on the system level. These investigations can be provided to a power circuit designer for fully exploiting the benefit of power devices. Additionally, they can serve as accurate device models and guidelines considering the switching performance. The BG concept utilized for JFETs has been also used for further development of SiC junctionbarrier Schottky (JBS) diodes. Especially, this design concept gives a great impact on high temperature operation due to efficient shielding of the Schottky interface from high electric fields. By means of simulations, the device structures with implanted and epitaxial p-grid formations, respectively, are compared regarding threshold voltage, blocking voltage, and maximum electric field at the Schottky interface. The results show that the device with an epitaxial grid can be more efficient at high temperatures than that with an implanted grid. To realize this concept, the device with implanted grid was optimized using simulations, fabricated and verified through experiments. The BG JBS diode clearly shows that the leakage current is four orders of magnitude lower than that of a pure Schottky diode at an operation temperature of 175 oC and 2 to 3 orders of magnitude lower than that of commercial JBS diodes. Finally, commercialized vertical trench JFETs are evaluated both in simulations andexperiments, while it is important to determine the limits of the existing JFETs and study their performance in parallel operation. Especially, the influence of uncertain parameters of the devices and the circuit configuration on the switching performance are determined through simulations and experiments. / Kiselkarbid (SiC) har en högre genombrottsfältstyrka än kisel, vilket möjliggör tunnare och mer högdopade driftområden jämfört med kisel. Följaktligen kan förlusterna reduceras jämfört med kiselbaserade omvandlarsystem. Dessutom tillåter SiC drift vid temperatures upp till 250 oC. Dessa utsikter gör att SiC anses vara halvledarmaterialet för moderna effekthalvledarkomponenter för hög verkningsgrad, hög temperature och hög kompakthet. Förutom materialegenskaperna är också komponenttypen avgörande för att bestämma systemets prestanda. Jämfört med SiC MOSFETen och bipolärtransistorn i SiC är SiC JFETen en mycket lovande component, eftersom den är spänningsstyrd och saknar tillförlitlighetsproblem med oxidskikt. Dess kanal styrs an en PNövergång. Emellertid är dagens JFETar inte optimerade med hänseende till on-state resistans, styrbarhet av tröskelspänning och Miller-kapacitans. I denna avhandling introduceras state-of-the-art SiC JFETar med buried-grid (BG) teknologi. Denna åstadkommes genom epitaxi och etsningsprocesser. Medelst simulering undersöks nya concept för normally-on och normally-off BG JFETar med blockspänningen 1200 V. Såvä statiska som dynamiska egenskper undersöks. Dessutom görs två fallstudier vad avser totalförluster på systemnivå. Dessa undersökningar kan vara värdefulla för en konstruktör för att till fullo utnyttja fördelarna av komponenterna. Dessutom kan resultaten från undersökningarna användas som komponentmodeller och anvisningar vad gäller switch-egenskaper. BG konceptet som använts för JFETar har också använts för vidareutveckling av så kallade JBS-dioder. Speciellt ger denna konstruktion stora fördelar vid höga temperature genom en effektiv skärmning av Schottkyövergången mot höga elektriska fält. Genom simuleringar har komponentstrukturer med implanterade och epitaxiella grids jämförst med hänseende till tröskelspänning, genombrottspänning och maximalt elektriskt fält vid Schottky-övergången. Resultaten visar att den epitaxiella varianten kan vara mer effektiv än den implanterade vid höga temperaturer. För att realisera detta concept optimerades en komponent med implanterat grid med hjälp av simuleringar. Denna component tillverkades sedan och verifierades genom experiment. BG JBS-dioden visar tydligt att läckströmmen är fyra storleksordningar lägre än för en ren Schottky-diod vid 175 oC, och två till tre storleksordningar lägre än för kommersiella JBS-dioder. Slutligen utvärderas kommersiella vertical trench-JFETar bade genom simuleringar och experiment, eftersom det är viktigt att bestämma gränserna för existerande JFETar och studera parallelkoppling. Speciellt studeras inverkan av obestämda parametrar och kretsens konfigurering på switchegenskaperna. Arbetet utförs bade genom simuleringar och experiment. / <p>QC 20150915</p>

No description available.

Das Transport- und Relaxationsverhalten verschiedener Quantenmodelle wird untersucht. Den ersten Teil der vorliegenden Arbeit bildet die Untersuchung der Transporteigenschaften von speziellen finiten modularen Quantensystemen bzgl. einer Boltzmann-Gleichung (BG). Diese Systeme, in denen unter bestimmten Bedingungen diffusiver Transport beobachtet werden kann, wurden mit verschiedenen Methoden zur Beschreibung von Quantentransport untersucht. Dabei zeigt sich, dass sich das diffusive Transportverhalten in diesen Systemen aus der zugrunde liegenden Schrödinger Dynamik heraus beschreiben lässt. Ob die diffusive Dynamik in diesen Systemen ebenfalls auf der Basis einer BG beschrieben werden kann, wird analytisch und numerisch untersucht. Im zweiten Teil wird die Relaxationsdynamik in quantenmechanischen Vielteilchensystemen untersucht. Speziell wird versucht, die Lebensdauern von angeregten Elektronen (Löchern) in Metallen, welche mit dem Fermi-See der Elektronen wechselwirken, mittels der zeitfaltungsfreien Projektionsoperator-Methode (TCL) zu bestimmen. Letztere liefert einen analytischen Ausdruck für die Dämpfungsrate (inverse Lebensdauer), welche temperaturabhängig ist und im Rahmen von Standard-Streuprozessen interpretiert werden kann. Um dieses analytische Ergebnis zu testen, wird es angewendet, um die Lebensdauern angeregter Elektronen (Löcher) in Aluminium zu bestimmen, für das ein Jellium Modell verwendet wird. Die Ergebnisse, die man über Monte-Carlo-Integration erhält, werden mit experimentellen und theoretischen Daten aus Selbstenergie-Rechnungen verglichen. Des Weiteren werden die Lebensdauern angeregter Elektronen in Kupfer ermittelt, für das ein Tight-Binding-Modell verwendet wird.