Ce travail s'inscrit dans le projet français de gazéification de la biomasse : le projet Gaya. C'est un vaste programme R&D partenarial coordonné par GDF SUEZ et soutenu par l'ADEME. L'objectif du projet Gaya est de développer une filière décentralisée de production de bio-méthane à partir de la gazéification de la biomasse selon un procédé thermochimique de deuxième génération. L'objectif de cette thèse est de réaliser un modèle de pyrolyse de biomasse représentatif des conditions du lit fluidisé de gazéification développé dans ce projet. Un pilote expérimental, le four à image, a été développé pour reproduire au mieux les conditions de chauffage d'un lit fluidisé à 850°C. Ce pilote permet de récupérer l'ensemble des produits de pyrolyse pour une analyse ultérieure. De là, les cinétiques des réactions de pyrolyse sont déterminées par modélisation des processus physico-chimiques et optimisation à partir des résultats expérimentaux. Le craquage des vapeurs primaires de pyrolyse éjectées de la particule de biomasse est étudié durant 300 millisecondes après leur éjection de la particule de biomasse. Ces expériences de craquage sont menées sur le montage expérimental combinant un réacteur tubulaire de pyrolyse et un réacteur parfaitement auto-agité de craquage. Le modèle développé permet de représenter la pyrolyse de la biomasse introduite dans le réacteur de gazéification / This study contributes to the French biomass gasification project: Gaya project. It is a large R&D project financed by ADEME and coordinated by GDF SUEZ. The project GAYA will develop a demonstration platform for a new biomass gasification and methanation process. In this context, our objective is to build a biomass pyrolysis model, representative of the conditions encountered in the fluidized bed gasifier developed in this project. An experimental machine, the vertical image furnace, has been developed to reproduce the heat conditions of the fluidized bed gasifier at 850°C. This experimental model permits to collect all the pyrolysis products for a later analysis. Then, kinetics parameters are determined from both the physico-chemical process and the optimization of experimental results. The thermal cracking of condensable vapours, is studied during the first 300th milliseconds after their ejection from the biomass particle. For this purpose, cracking experiments are led on the experimental machine which combines a tubular pyrolysis reactor and a continuous self-stirred tank cracking reactor. The model developed allows us to represent the biomass pyrolysis introduced in the gasification reactor

Le remplacement des lasers à colorant émettant dans la gamme 550-570 nm, à l'aide de lasers solides, représente un véritable enjeu industriel. Les applications sont multiples tant dans le domaine de la recherche biomédicale que dans celui de la métrologie. Quelques solutions ont été développées à 561 nm et à 553 nm. Néanmoins, elles ne permettent pas de fournir des lasers intégrables parfaitement mono-fréquences émettant en continu un faisceau gaussien, d'une puissance supérieure ou égale à 200 mW. Dans ces travaux, nous proposons une étude théorique et expérimentale de cavités lasers solides monolithiques à base de Nd:YAG pompé par diode, doublé en fréquence en intra-cavité, à l'aide d'un cristal non-linéaire de KTP. Ces cavités, constituées de plusieurs cristaux, sont contactées par adhérence moléculaire. Elles ne contiennent aucune optique de mise en forme des faisceaux et présentent la particularité de comporter un double filtre de Lyot. Nous présentons les résultats obtenus avec des cavités émettant à 561 nm pour des puissances supérieures ou égales à 300 mW. Puis, après une étude statistique et une analyse des résultats de test de ces cavités à long terme (> 6000 heures), nous discutons des problèmes éventuels de fiabilité et nous suggérons des axes d'amélioration. Ayant réussi à faire osciller, pour la première fois, la raie à 1106 nm du Nd:YAG, nous montrons ensuite la faisabilité d'un laser compact mono-fréquence continu à 553 nm, émettant une puissance de 200 mW à 500 mW avec un rendement de conversion pompe/laser visible de l'ordre de 19 %. Pour conclure, nous montrons qu'il est possible, dans des cavités de ce type, de faire osciller des raies Raman issues des raies fondamentales et de les doubler en fréquence en intra-cavité. Nous ouvrons ainsi la porte à toute une famille de lasers solides émettant dans la gamme 540-600 nm. / Replacement of dye lasers emitting in the range 550-570 nm, using solid state lasers, is a real industrial issue. There are many applications both in the field of biomedical research than in metrology. Some solutions have been developed for 561 nm and 553 nm. However, they do not provide fully integrated lasers emitting single-frequency continuous Gaussian beam with a power equal or up to 200 mW. In this work, we propose a theoretical and experimental study of solid monolithic cavity lasers based on Nd:YAG diode-pumped, frequency-doubled intra-cavity, using a non-linear crystal of KTP. These cavities, consisting of several crystals, are contacted by molecular adhesion. They contain no optical layout of the beams and they have the particularity of including a double Lyot filter. We present the results obtained with those cavities emitting at 561 nm for powers greater than 300 mW. Then, after a statistical study and analysis of test results of these cavities in the long term (> 6000 hours), we discuss about the potential problems of reliability and we suggest areas for improvement. For the first time, we show that the line at 1106 nm of the Nd: YAG can oscillate in this type of cavity. Then we demonstrate the feasibility of a compact single-frequency laser at 553 nm continuously, emitting a power of 200 mW to 500 mW with a conversion efficiency of pump / visible laser of about 19%. Finally, we show that it is possible, in cavities of this type, to oscillate the Raman lines from the lines of the fundamental and doubled frequency in intra-cavity. We open the door to a whole family of solid state lasers emitting in the range of 540-600 nm.

Bakgrund: Behovet av palliativ vård kommer att öka i takt med att befolkning blir äldre och lever allt längre. Det kommer bli fler äldre personer med kroniska sjukdomar som har andra sjukdomsförlopp jämfört med cancer. Det är viktigt för kvaliteten av den palliativa vården att brytpunktssamtal erbjuds. Med kvalitet menas bland annat delaktighet, symtomlindring och stöd för närstående. Detta innebär en utmaning för hälso- och sjukvården som måste uppmärksamma när vården ändrar riktning mot vård i livets slutskede. Äldre personer erbjuds i mindre utsträckning brytpunktssamtal än yngre personer. Distriktssköterskan har en betydelsefull roll i den palliativa vården inom den kommunala hemsjukvården och ska främja äldre personers möjlighet att få information samt delta i beslut som rör den egna vården, vilket ett brytpunktssamtal innebär. Syfte: Syftet med studien var att undersöka samband mellan brytpunktssamtal och andra faktorer, för äldre personer i palliativ vård, vid tillfällen då dödsfallet varit förväntat. Metod: Detta är en kvantitativ retrospektiv registerstudie med data hämtad från svenska palliativregistret. Resultat: Det fanns stora skillnader inom gruppen äldre huruvida brytpunktssamtal erbjöds eller inte. Ju äldre personen var desto mindre odds för att brytpunktssamtal erbjöds. Kön eller diagnos påverkade inte. När brytpunktssamtal erbjudits var närstående i högre utsträckning på plats när den äldre personen dog och när brytpunktssamtal inte erbjudits var personal i högre utsträckning de enda närvarande än då brytpunkssamtal erbjudits. Slutsats: Den palliativa vården är ojämlik och äldre personer riskerar att utsättas för onödigt lidande. Distriktssköterskan i kommunal hemsjukvård bör sätta extra fokus på denna grupp för att uppmärksamma övergång till vård i livets slutskede. / Background: The need of palliative care will increase as the population ages and lives longer. There will be more old people with chronic diseases that will have other disease progression than those with cancer. To achieve a high quality in the palliative care it´s important that the physician gives the dying person information about the imminent death a so-called breakpoint conversation. A high-quality means among other things patient participation, symptom relief and support to relatives. This means a challenge for the healthcare workers who must pay attention to when care changes direction towards care in the end of life. Older people are to a lesser extent offered breakpoint conversation than younger people. The district nurse has an important role in the palliative care for older people in municipal health and medical care and are supposed to promote elderly people's opportunity to have information about their disease course that gives them ability to be involved with decisions about their own care planning, which means paying attention to when it´s time to offer a breakpoint conversation. Aim: The purpose of this study was to examine relations and other factors associated with breakpoint conversation in palliative care for elderly people when death were imminent. Method: The study is a quantitative retrospective registry study based on data from the Swedish register of palliative care. Results: There are a significant difference within the group of old people when it comes to being offered a breakpoint conversation, with a negative trend where older people are less likely to get a breakpoint conversation. Gender and diagnosis had no impact. When a breakpoint conversation was offered, relatives were to a greater extent present when death occurred, and staff were more often the only ones present when a breakpoint conversation weren't offered. Conclusion: The palliative care is unequal and older people risk being exposed to unnecessary suffering. The district nurse in municipal home care should put an extra focus on this group of elderly people were death is imminent.

Dans l'industrie sidérurgique, les fours de réchauffage sont les plus grands consommateurs d'énergie après les hauts fourneaux. Réduire leur consommation énergétique est donc la préoccupation majeure de la commande des fours. Dans un four de réchauffage, des brames d'acier sont chauffées en traversant successivement plusieurs zones, de la température ambiante à un profil de température homogène de 1250 °C en sortie du four, avant d’être laminées dans les laminoirs à chaud. La température de brames est contrôlée par une structure de commande hiérarchisée à deux niveaux (niveau 1 et 2).L'objectif de ces travaux est d'améliorer la performance du chauffage et donc de réduire la consommation énergétique du four via une stratégie de commande prédictive distribuée hiérarchisée sur les deux niveaux de commande. Une approche de commande prédictive distribuée est tout d’abord développée pour le niveau 1 afin de suivre les consignes de température de zone, prenant en compte les couplages entre les zones et induisant une moindre complexité d’implantation par rapport à une approche centralisée. L’implantation industrielle a permis une amélioration significative de la précision du suivi de température et une réduction de la consommation d'énergie de 3%. Une deuxième étape propose l’élaboration de la commande prédictive hiérarchisée du niveau 2 afin, à partir de la consigne de température de brame, de déterminer les consignes de température optimales des zones en se fondant sur un modèle de transfert thermique du four. Les résultats de simulation, comparés aux données industrielles, montrent une réduction de la consommation énergétique de 5% et une meilleure qualité de chauffage des brames. L’approche précédente est enfin étendue pour prendre en compte et optimiser le cadencement des brames afin d’augmenter la productivité du four. La simulation montre une augmentation potentielle de productivité du four de 15 tonnes par heure tout en améliorant la qualité de chauffage des brames. / In steel industry, reheating furnaces are the biggest energy consumers after blast furnaces. As a result, reduction of energy consumption is the major concern of furnace control. In a walking-beam slab reheating furnace, steel slabs are heated by moving through successive zones from ambient temperature to a homogenous temperature profile of 1250°C at the furnace exit, to be rolled subsequently in the hot rolling mills. Temperature of slabs is controlled mainly by a two-level hierarchical structure, so called level 1 and level 2.The aim of this thesis is to improve the heating performance and consequently to reduce the energy consumption of the furnace by using hierarchical distributed model predictive control (MPC) strategy for both levels. In a first step, distributed model predictive controllers are developed for the level 1 in order to track zone temperature set-points. The distributed feature of the control law enables to consider coupling effects between zones while reducing the computation complexity compared to a complete centralized approach. The industrial results showed significant improvement on temperature tracking accuracy and an energy consumption reduction of 3%. In a second step, the hierarchical MPC is constructed for the level 2 in order to determine the optimal zones temperature setpoint from the slab temperature setpoint, based on a numerical heat transfer model of the furnace. The simulation results obtained with this strategy compared against industrial data show an energy consumption reduction of 5% and a better heating quality. The previous structure is finally extended to take into account and optimize the scheduling of the slabs within the MPC level 2 in order to increase productivity of the considered furnace. The simulation shows a potential increase of productivity of the furnace of 15 tons per hour while improving the slab heating quality.

Sammanfattning   Revision är ett än mer aktuellt ämne nu än på flera decennier då det debatteras vitt och brett kring vad en revisor skall eller bör göra. I och med de tidigare införda byrårotationskraven begränsar det företag av allmänt intresse att inte under mer än maximalt tio år använda samma revisionsbyrå, med chans till förlängning. Vi har därför valt att undersöka hur längden på revisionsuppdragen kan inverka på stora onoterade bolag i en mindre geografisk zon, i vårt fall Umeå kommun med omnejd genom att intervjua tre revisorer och deras klienter.   Baserat på problemdiskussionen har vi bestämt följande problemformulering för studien.      Hur upplever revisionsbyråerna och deras klienter att oberoendet samt revisionskvalitet samspelar med revisionsprocessen vid korta respektive långa revisionsuppdrag?   Syftet med vår studie är att undersöka hur förhållandet mellan klient och revisor upplevs ha en samverkan med kvaliteten i revisionen samt på revisorernas oberoende till deras klienter över tid. Detta kan ligga till grund för framtida diskussioner gällande byrårotation för huruvida oberoende och revisionskvalitet utvecklas över tid under revisionsuppdraget.   Med en kvalitativ ansats har vi genomfört nio intervjuer med tre revisorer samt sex klienter. Klientförhållandena till respektive revisor är ett långvarigt revisionsuppdrag (fler än fem år) och ett kortvarigt revisionsuppdrag (mindre än 5 år sedan övertagandet). Denna unika inblick i revisor-klientförhållandet kopplas till flertalet faktorer samt teorier vilka kan ha en samverkan och förklaring till förändringen i oberoendet samt revisionskvaliteten.    Vi kommer i vår studie fram till att revisionsprocessen ser väldigt lik ut vid korta samt långa revisionsuppdrag där första året är speciellt omfattande, men år 2 och framåt vanligtvis är lika omfattande år efter år. Vad gäller oberoende finner vi att desto längre relation som skapas mellan klient och revisionsbyrå desto mer omfattande blir rådgivningen till klienten vilket kan påverka revisionsbyråns oberoende mot klienten rent finansiellt. Vidare är revisionskvalitet en term som definieras olika, men i teorin hävdar flertalet att detta kan speglas av oberoendet till klienten. I vår studie har definitionen uppfattats olika mellan revisor och klient vilket visar på ett förväntningsgap mellan de båda. Enligt respondenterna är revisionskvalitet något som skulle kunna förbättras av byrårotation när flera anser att långa revisionsuppdrag kan bli för rutinmässiga och att det skulle vara bra om nya individer kommer in och tittar på uppdraget från ett nytt perspektiv.   Förslag till vidare forskning skulle till exempel vara en enkätundersökning med ett mer omfattande geografiskt område där fler företag av större storlek innefattas av populationen för att kunna jämställa dessa med de företag som redan omfattas av reglerna om obligatorisk byrårotation.   Nyckelord: Audit, big four, big seven, audit quality, audit independence, audit firm rotation, auditor rotation, expectation gap, evidential matter, audit procedures och audit tenure.

Nesta tese obtemos, de um ponto de vista matemáticamente rigoroso, a parte inferior do espectro de energia-momento de dois modelos de teorias quânticas de campo com tempo imaginário em redes de dimensão $d+1$ (resultados explícitos para o caso $d = 3$ e matrizes de Dirac) que contém férmions: um modelo puramente fermiônico com interação quártica nos campos fermiônicos de $N$ componentes (modelo de Quatro-Férmions) e um modelo de cromodinâmica quântica. Para o modelo de Quatro-Férmions, $\\kappa$ é o parâmetro de hopping, $M_0$ é a massa bare dos férmions e $\\lambda$ é o parâmetro de interação. Uma expansão de polímeros garante a existência das funções de correlação no limite termodinâmico, na região onde $|\\frac{\\kappa}|$ é pequeno. A análise do espectro é baseada em representações espectrais para funções de correlação de dois e quatro férmions. A análise das funções de correlação adequadas é simplificada pelo uso de simetrias, em particular, de uma {\\em nova} simetria de Reflexão Temporal que aparece no nível das funções de correlação. A determinação do espectro é executada através de um estudo detalhado das taxas de decaimento das funções de correlação. Até próximo ao limiar de três partículas, o espectro de energia e momento exibe curvas de dispersão isoladas que são identificadas com partículas e estados ligados de duas partículas. No subespaço de uma partícula, o espectro consiste em uma curva de dispersão isolada. A massa da partícula é de ordem $-\\ln \\kappa$. O espectro de duas partículas aparece como soluções de uma equação de Bethe-Salpeter, resolvida primeiro em uma aproximação em escada. O espectro de duas partículas contém uma banda de duas partículas livres de largura finita. A existência de estados ligados acima ou abaixo da banda de duas partículas depende do fato do modelo apresentar ou não dominação gaussiana. Um parâmetro $\\aleph$ é dado para medir a dominação gaussiana. Para $\\aleph=0$, nenhum estado ligado ocorre. Para $\\aleph>0$, o estado ligado ocorre abaixo da banda de duas partículas. Para $\\aleph<0$, o estado ligado aparecem acima desta banda. Os resultados obtidos nesta aproximação em escada podem ser estendidos para o modelo completo através de um controle rigoroso das contribuições que diferenciam essas duas situações. Em uma segunda parte, idéias análogas são aplicadas para analisar o espectro do modelo de cromodinâmica quântica. Em particular, nós mostramos a existência dos pentaquarks no regime de acoplamento forte (acoplamento entre as plaquetas $0 <\\beta= \\frac{g^2_0} \\ll \\kappa $). O modelo possui simetria de calibre $SU(3)_c$ e de sabor $SU(2)_f$. Os pentaquark revelados são superposições de estados ligados de mésons e bárions. Apenas estados com um número ímpar de férmions e abaixo do limiar de energia meson-bárion são considerados. O pentaquark é determinado usando uma aproximação em escada para uma equação Bethe-Salpeter. Na ordem dominante em $\\beta$, a massa deste estado é aproximadamente $-5 \\ln\\kappa$ e sua energia de ligação é de ordem $\\textrm(\\kappa^2)$. O estado mais fortemente ligado tem isospin $I=\\frac$. Para $I=\\frac$ não há estados ligados. Estes resultados mostram uma dependência nos spins dos méson e bárion. Esta análise mostra que um potencial de troca de quark-anti-quark de $\\textrm(\\kappa^2)$ é a interação dominante, mas não há uma interpretação de troca de mésons. / In this thesis, we obtain, from a mathematically rigorous point of view, the low-lying energy-momentum spectrum of two $3+1$ dimensional imaginary time lattice quantum filed theory with fermion fields (we give explicit results for the case $d = 3$ and Dirac matrices): a pure fermionic model with quartic interaction in the $N$-component fermion field and a quantum chromodynamics model. For the Four-Fermion model, $\\kappa$ denotes the hopping parameter, $M_0$ the fermion bare mass and $\\lambda$ the interaction parameter. A polymer expansion show the existence of the model correlation functions in the thermodynamic limit, in the region where $|\\frac{\\kappa}|$ is small enough. The analysis of the spectrum is based on spectral representations of two- and four- point correlation functions. The analysis of such adequate correlation functions is simplified by the help of symmetries, in particular, by a {\\em new} Time Reflection symmetry, which appear in the level of correlation functions. The exact determination of the spectrum is done using a detailed study of the decay rates of the correlations. Up to near the 3 particle threshold, the energy-momentum spectrum exhibits isolated dispersion curves that are identified as particles and bound states. In the one-particle subspace, the spectrum consist in just a isolated dispersion curve. The mass of the associated particle is of order $-\\ln \\kappa$. The two-particle spectrum shows up as solutions of a Bethe-Salpeter equation, which is solved first in a ladder approximation. The two-particle spectrum contains a two free particles band of finite width. The existence of bound states above or below the band depends on wherever the model Gaussian domination holds. A parameter $\\aleph$ is given to measure the Gaussian domination. For $\\aleph=0$, no bound state occurs. For $\\aleph>0$, a bound state appears bellow the two-particles band. For $\\aleph<0$, the bound state appears above this band. The result obtained in this ladder approximation can be extended to the full model by a rigorous control of the contributions that differ these two cases. In a second part, analog ideas are applied to analyze the spectrum of a quantum chromodynamics model. In particular, we show the existence of pentaquarks in the strong coupling regime (plaquette coupling $0 <\\beta= \\frac{g^2_0} \\ll \\kappa $). The model has a $SU(3)_c$ gauge symmetry and a $SU(2)_f$ flavor symmetry. The reveled pentaquarks are superpositions of meson-baryon bound states. Only states with an odd number of fermions and bellow the meson-baryon threshold are considered. The pentaquark are determined using a ladder approximation to the Bethe-Salpeter equation. In the dominant order in $\\beta$, the bound state mass is $\\approx -5 \\ln\\kappa$ and the binding energy is of order $\\textrm(\\kappa^2)$. The most strongly bounded bound state has isospin $I=\\frac$. For $I=\\frac$, there is no bound state. These results shows a dependence in the spins of the meson and baryon. This analysis show that a $\\textrm(\\kappa^2)$ quark-anti-quark exchange potential is the dominant interaction, although there is not a meson exchange interpretation.

Cette thèse est dédiée aux convertisseurs multiniveaux et aborde les problématiques liées à la compensation des perturbations générées sur un réseau électrique, telles que celles produites par les fours à arc. Elle est composée de quatre chapitres couvrant les thématiques de la modélisation des réseaux électriques, des convertisseurs de tension, du contrôle commande et des stratégies de compensation, accompagnés de simulations et de résultats expérimentaux obtenus sur des équipements industriels de forte puissance. Les applications réseaux étant diverses et variées, les convertisseurs multiniveaux sont ici étudiés dans le but d’être raccordés directement sur des réseaux de distribution. Pour cela, un état de l’art des différentes topologies de convertisseurs de tension (classiques et multiniveaux) est présenté et les topologies dites modulaires, sont retenues pour une étude plus poussée. Ces convertisseurs utilisent des modules de puissance à base de ponts en H, de ½ ponts en H ou de ponts en H 3-niveaux connectés en cascade. Ils permettent ainsi de créer différents types de configurations ou couplages appelés dans ce mémoire : étoile, triangle et étoiles symétriques. Les différents modules et les stratégies pour les commander sont étudiés autour d’un composant de puissance (de type IGBT 2.5kV/1.5kA). A travers les domaines électrique et thermique, une méthode est proposée afin d’estimer les pertes, les températures de jonction et déterminer ainsi les limites d’utilisation d’un tel composant de puissance. Le dimensionnement et la fiabilité de ces convertisseurs est également abordé pour chacune des configurations envisagées, afin de dégager les avantages et inconvénients pour une application réseau. D’une façon générale, la stratégie de contrôle des convertisseurs multiniveaux est ardue, principalement lié au fait que de multiples sources de tensions continues doivent être contrôlées. Dans cette optique, des stratégies de contrôle sont proposées et validées en simulation selon les types de modules et de configurations utilisés pour la compensation des perturbations d’un four à arc. Enfin, la dernière partie de ces travaux est consacrée aux résultats expérimentaux sur la base d’un compensateur industriel dénommé DSVC (Dynamic Static Var Compensator), pour la compensation des fours à arc. Les différents résultats obtenus sur plusieurs sites industriels ont ainsi permis la validation des travaux exposés dans ce mémoire / This thesis is dedicated to the multilevel converters and addresses issues related to compensation for disturbance generated on an electrical network such as those produced by arc furnaces. It is composed of four chapters covering the themes of modeling of electrical networks, voltage converters, control and compensation strategies, with simulations and experimental results obtained on high power industrial equipment. There are many networks applications and multilevel converters are here considered to be directly connected to distribution networks. Therefore, a state of the art of different voltage converters, classics and multilevel topologies, is presented and the topologies called modular are retained for further studies. These converters use modular power cells made of H bridges, ½ bridges or 3-level H bridges connected in cascade. They allow to create different types of configurations or couplings called in this memory: star, delta and double stars. The different modules and the strategies to control them are investigated around the same switching power component (IGBT 2.5kV/1.5kA). Through electrical and thermal fields, a method is proposed to estimate their losses, junction temperatures in order to determine the limits of use of such a component of power. Sizing and reliability of these converters is also discussed for each considerer configurations in order to identify the advantages and disadvantages for a network application. Generally, the multilevel converters control strategy is difficult because of the multiple sources of DC voltages to control. In this context, control strategies are proposed and validated in simulation according to the types of modules and configuration used to compensation for disturbance of an arc furnace. Finally, the last part of this thesis is devoted to the experimental results based on an industrial compensator DSVC (Dynamic Static Var Compensator) for arc furnace compensation. The different results obtained at several industrial sites have thus allowed the validation of the various works exposed in this thesis

Este trabalho investiga a influência dos efeitos da mistura de quatro ondas (FWM -. Four- Wave Mixing) durante o estabelecimento de caminhos ópticos em uma rede GMPLS/DWDM (Generalized MultiProtocol Label Switching/Dense Wavelength Division Multiplexing). Para minimizar seus impactos e assim reduzir o bloqueio total da rede, são propostas estratégias por meio de extensões ao RSVP-TE (Resource Reservation Protocol-Traffic Engineering). A partir de uma plataforma de simulação que emula e integra a camada óptica e o Plano de Controle da arquitetura GMPLS, a solução proposta é validada. Os vários métodos de alocação de comprimentos de onda são avaliados e as contribuições na redução dos sinais interferentes quantificadas. Para minimizar o bloqueio na rede, uma nova classe de métodos de alocação, classificados como híbridos, é definida e seu desempenho é avaliado. O bloqueio da rede em função da variação de parâmetros que reforçam a eficiência da FWM, tais como a quantidade e espaçamento entre canais, é observado, confirmando a necessidade de métodos de alocação especialistas para gerenciamento do QoS (Quality of Service) óptico em cada caminho a ser estabelecido. Os resultados obtidos comprovam a eficiência da solução proposta e evidenciam a necessidade de um Plano de Controle GMPLS com acurada visibilidade das restrições da camada física, tanto os efeitos estáticos quanto às degradações associadas ao comportamento dinâmico da rede. / This work investigates the effects of the Four-Wave Mixing (FWM) during the lightpaths establishment in a GMPLS/DWDM (Generalized Multiprotocol Label Switching / Dense Wavelength Division Multiplexing) network. In order to minimize their impacts and thus reduce network blocking, strategies based on RSVP-TE (Resource Reservation Protocol- Traffic Engineering) extensions are proposed. The proposed solution is validated using a simulation platform that integrates and emulates the optical layer and the GMPLS Control Plane. The various wavelength allocation methods are evaluated and their contributions on the reduction of interfering signals are quantified. In order to minimize the network blocking, a new class of allocation methods (classified as hybrids) is defined and its performance is evaluated. The network blocking caused by the parameters that enhance the FWM efficiency, such as the number and spacing between channels, is also observed, confirming the need of specialized wavelength allocation methods for managing the optical QoS for each lightpath. The results obtained ascertain that the proposed solution is efficient and demonstrate the need for a GMPLS Control Plane endowed with an accurate visibility of the restrictions in the physical layer, concerning both static and dynamic effects.

Estudamos o efeito de Conjugação de Fase por Mistura Degenenerada de Quatro Ondas em Al2O3:Cr+3 (Rubi) e GdAlO3:Cr+3 com um laser de Ar (&#955;=5145 &#197;). Obtivemos eficiência aproximadamente quatro vezes maior no GdAlO3:Cr+3 (onde este trabalho é original) que no Rubi o que nos motivou a investigar as propriedades físicas que são relevantes para o fenômeno nestes sistemas (isto não foi bem compreendido no trabalho anterior em Rubi). Desenvolvemos um método interferométrico muito sensível para medida dos coeficientes não lineares do índice de refração n2 destes materiais (que não eram conhecidos) Com estes valores de n2 calculamos a eficiência de Conjugação de Fase em bom acordo com experiência. / We have studied the effect of Phase Conjugation by Degenerate Four Wave Mixing in Al2O3:Cr+3 (Rubi) and GdAlO3:Cr+3 with an Ar (&#955;=5145 &#197;). We obtained efficiency ?approximately? 4 times greater in GdAlO3:Cr+3 (where this work is original) than in Rubi and this have motivated us to investigate the physical properties that are important to explain this phenomenon in these materials (what wasn\'t well understood in the previous paper on Rubi(10)). We developed an interferometric method very sensitive to measure the nonlinear coeficient of refractive index n2 of these materials (what wasn\'t known). With these values of n2 we calculated the efficiency of the Phase Conjugation in good agreement with the experience.

O comportamento da dinâmica lateral de veículos automotivos com esterçamento nas quatro rodas é estudado com o auxílio de uma ferramenta computacional de modelagem e simulação de sistemas multicorpos. São utilizadas duas estratégias de controle do esterçamento das rodas traseiras para a avaliação de suas principais características. Uma das estratégias esterça as rodas traseiras em função do ângulo de esterçamento do volante, e a outra esterça as rodas traseiras em função do ângulo de esterçamento do volante e da velocidade longitudinal do veículo. O teste utilizado para as análises é a entrada degrau de esterçamento, onde é avaliada a resposta transitória e de regime da aceleração lateral, da velocidade de guinada e do ângulo de rolagem dos veículos. Os resultados das simulações mostram que os veículos com esterçamento nas quatro rodas têm o tempo de resposta da velocidade de guinada maior, e da aceleração lateral e do ângulo de rolagem menores que o veículo convencional. Também apresentam uma diminuição no ganho da aceleração lateral, da velocidade de guinada e do ângulo de rolagem. Além disso apresentam uma característica subesterçante mais acentuada. Essas características são mais evidentes no veículo com estratégia de controle função do esterçamento do volante. Os resultados obtidos correspondem ao comportamento dos veículos com esterçamento nas quatro rodas apresentado na literatura. / The lateral dynamic behavior of the automotive vehicles is studied with the aid of a computational tool for multibody systems modeling and simulation. Two rear wheel steering control strategies are used for evaluation of the main four wheel steering characteristics. One strategy steer the rear wheels as a function of the steering wheel angle, and the other one, steer the rear wheels as a function of the steering wheel angle and the speed. The steer step input is the test used, where the lateral acceleration, the yaw rate and the roll angle transient and stead state response are evaluated. The simulation results show that the four wheel steering vehicles have a slower yaw rate time response, and a fast lateral acceleration and roll angle time response than the conventional vehicle. Also four wheel vehicles show a reduction in lateral acceleration, yaw rate a.nd roll angle gain. Moreover they are more understeer than the conventional vehicle. These characteristics are particularly more evident on the vehicle with steer dependent system. The obtained results correspond with four wheel steering vehicles behavior founded in literature.