Dans cette thèse nous contribuons à répondre aux questions sur les processus dynamiques sur réseaux temporels. En particulier, nous etudions l'influence des représentations de données sur les simulations des processus épidémiques, le niveau de détail nécessaire pour la représentation des données et sa dépendance des paramètres de la propagation de l'épidémie. Avec l'introduction de la matrice de distributions du temps de contacts nous espérons pouvoir améliorer dans le futur la précision des prédictions des épidémies et des stratégies d'immunisation en intégrant cette représentation des données aux modèles d'épidémies multi-échelles. De plus nous montrons comment les processus épidémiques dynamiques sont influencés par les propriétés temporelles des données. / In this thesis we contribute to provide insights into questions concerning dynamic epidemic processes on data-driven, temporal networks. In particular, we investigate the influence of data representations on the outcome of epidemic processes, shedding some light on the question how much detail is necessary for the data representation and its dependence on the spreading parameters. By introducing an improvement to the contact matrix representation we provide a data representation that could in the future be integrated into multi-scale epidemic models in order to improve the accuracy of predictions and corresponding immunization strategies. We also point out some of the ways dynamic processes are influenced by temporal properties of the data.

Das Verständnis der komplexen Interaktionen innerhalb des weltweiten Transportnetzes ist ein essentieller Schritt auf dem Weg zur Vorhersage der Krankheitsausbreitung und Entwicklung von effektiven Gegenmaßnahmen. Ungeachtet der weltweiten Vernetzung werden die politischen Entscheidungen oft von nationaler, regionaler und egozentrischen Denkweise geleitet. Die Ebola-Epidemie in 2014 demonstrierte deutlich, dass solche Herangehensweise modernen Epidemien nicht gerecht werden kann. In dieser Dissertation werden mehrere Methoden entwickelt, welche es ermöglichen während einer Epidemie die globalen Teilnehmer entsprechend ihrer Rolle einzustufen und das Risiko des Krankheitsexports zu berechnen. Die Methodik wird analytisch und numerisch ausführlich diskutiert. Darüber hinaus werden Lösungen für hypothetische und reale Epidemien auf dem Flugverkehrsnetz vorgestellt. Im zweiten Teil wird mit Hilfe eines vereinfachten spieltheoretischen Modells der Prozess der Ressourcenverteilung zur Epidemieeindämmung untersucht. Dabei erfolgt die Verteilung der Ressourcen von den Knoten und kann in egozentrischer oder altruistischer Weise erfolgen. Im Rahmen der Modells liegen die Optima für das altruistische und egozentrische System eng beieinander, solange der ausbruch räumlich konzentriert ist. In diesem Fall ist es optimal alle Ressourcen in den Ausbruchsknoten zu investieren. Bei lokal getrennten Ausbrüchen streben die Systeme verschiedene Gleichgewichte an. In allen Aspekten der Arbeit wird netzwerkbasierte Repräsentation des Systems verwendet, so dass die Orte durch Knoten innerhalb eines Transportnetzwerkes abgebildet werden. Die vorliegende Arbeit vereint mehrere Vorteileder etablierten Methoden: während der Schwerpunkt auf der Topologie des Netzwerkes liegt, berücksichtigt die vorgestellte Methodik den Ursprungsort der Epidemie. / The growing complexity of the global mobility is a key challenge for the understanding of the worldwide spread of emergent infectious diseases and the design of effective containment strategies. Despite global connectivity, containment policies are often based on national, regional and ’egocentric’ assessments of outbreak situations that are no longer effective or meaningful, as recently demonstrated by 2014 Ebola outbreak in West Africa, where months passed before a concerted, international effort followed. Despite the importance of the matter, optimal strategies in highly connected non-local settings are poorly understood. In the work at hand we propose a set of methods for more informed decision making during and prior to a pandemic. All of the studied systems are represented by networks in analogz the traffic networks, which play a dominant role during the global disease spreading. We introduce methods to calculate the risk of disease importation in a specific location and to determine the role of a node during an outbreak. Using the world aviation network, we demonstrate how the methods can be applied on real and hypothetical pandemics. We show that the airports can be divided into two distinct groups according to the role they take on in distributing the disease. Further, investigate the allocation of resources as a game theoretic dilemma. We embrace a bottom-up approach to this question, allowing the nodes of the network to distribute the resourses. We investigate egocentric and altruistic strategies and conclude that the optimal state of both systems are very similar if the outbreak is spacially confined. In this case allocation of resources ti the affected nodes is the optimal strategy. When there are multiple independent outbreaks, the optima diverge substantially. To foster the benefits of multiple approaches, the work at hand combines the information on the network topology but also regard some specifics of the outbreak at hand outbreak.

Les contacts face-à-face entre individus permettent de caractériser les réseaux sociaux et jouent un rôle prépondérant dans la compréhension des mécanismes de propagation des épidémies dans une population. De récentes avancées technologiques ont rendu possible l'acquisition de données précises sur les interactions humaines. Cette thèse présente, dans un premier temps, l'analyse de données de contacts collectées trois années de suite (2011, 2012 et 2013) dans un lycée français entre des étudiants de classes préparatoires. L'analyse a montré que la plupart des contacts se produisent entre étudiants de même classe et que les structures des contacts sont très similaires d'un jour sur l'autre. Dans un second temps, on compare différentes méthodes de collecte de données qui permettent d'obtenir des informations de nature différente (par exemple existence d'un contact face-à-face vs existence d'une amitié).L'utilisation de données rapportant les amitiés entre les étudiants ne permet pas d'obtenir une bonne estimation du réseau de contact (i.e., les amitiés ne correspondent pas forcément à des contacts face-à-face et vice versa) résultant en une sous-estimation du risque épidémique dans cette population.Dans la dernière partie, nous essayons de reproduire les biais provenant du réseau d'amitié en échantillonnant le réseau de contact. Ceci pourrait nous donner des indications sur comment compenser ces biais et comment utiliser des données incomplètes pour obtenir des prédictions fiables sur le risque épidémique. / Face-to-face contacts between individuals contribute to shape social networks and play an important role in determining how infectious diseases can spread within a population. Recently, technological advances have made it possible to obtain accurate data on human interactions.This thesis first presents the analysis of contact data collected three years in a row (2011, 2012 and 2013) in a French high school among students of "classes préparatoires" (i.e., studies taking place after high school and preparing for admission to higher education colleges). The analysis showed that most contacts occur within students of same classes and that contact patterns are very similar from one day to the next.Then, we compare different methods of data collection which allow to gather information of different nature (for instance existence of a face-to-face contact vs existence of a friendship).The use of data reporting friendships does not allow to obtain a good estimation of the contact network (i.e., friendships do not correspond necessarily to face-to-face contacts and vice versa) resulting in an underestimation of the epidemic risk in that population.Finally, we try to reproduce the biases coming from the friendship network by sampling the contact network. This might give hints on how to compensate these biases and how to use the information contained in incomplete data sets to obtain accurate predictions of the epidemic risk.

O Papilomavírus Humano (HPV) é uma prevalente infecção do mundo atual, sendo o comportamento sexual um fator determinante para a o acometimento da infecção. O objetivo deste trabalho foi estudar o HPV em diferentes sítios de infecção, buscando um maior entendimento do seu mecanismo de disseminação. Foram analisadas amostras das mucosas cervical, oral e do sangue de 50 pacientes do sexo feminino. Foram identificados o HPV-16, HPV-18, HPV-31 e HPV-33. Nenhuma paciente foi negativa para os quatro tipos nos três sítios. O HPV-16 foi o mais detectado e o mais prevalente nos três sítios, simultaneamente, 32 pacientes apresentaram esse perfil. Todos os tipos virais presentes no sangue, também estavam presentes na mucosa cervical, na mucosa oral ou em ambas. Foram identificados seis achados citológicos, sugestivos da infecção pelo HPV. Foi realizada a detecção dos transcritos virais de E6, E6/E7 e L1 nos três sítios. Os resultados do nosso trabalho demonstram a alta prevalência do HPV, a atividade viral nos três sítios analisados e a provável disseminação do vírus. / Human papillomavirus (HPV) is one of the most prevalent infections of the current world, with sexual behavior being one determining fator of infection. The objective of this study was to study HPV in different sites of infection, seeking a better understanding of its mechanism and spreading. Cervical, oral and blood mucosa samples from 50 female patients were analyzed. HPV-16, HPV-18, HPV-31 and HPV-33 were identified. No patient was negative in the four types at all three sites. HPV-16 was the most detected and the most prevalent in the three sites, simultaneously, 32 patients presented this profile. All viral types present in the blood were also present in the cervical mucosa, oral mucosa, or both. Six cytological findings were identified, suggestive of infection by HPV. Detection of viral transcripts of E6, E6 / E7 and L1 was performed at the three sites. The results of our study demonstrate the high prevalence of HPV, viral activity in the three sites analyzed and the probable virus spreading.

As redes sociais se tornaram um novo e importante meio de intercâmbio de informações, ideias e comunicação que aproximam parentes e amigos sem importar as distâncias. Dada a natureza aberta da Internet, as informações podem fluir muito fácil e rápido na população. A rede pode ser representada como um grafo, onde os indivíduos ou organizações são o conjunto de vértices e os relacionamentos ou conexões entre os vértices são o conjunto de arestas. Além disso, as redes sociais representam intrinsecamente a estrutura de um sistema mais complexo que é a sociedade. Estas estruturas estão relacionadas com as características dos indivíduos. Por exemplo, os indivíduos mais populares são aqueles com maior número de conexões. Em particular, é aceito que a estrutura da rede pode afetar a forma como a informação se propaga nas redes sociais. No entanto, ainda não está claro como a estrutura influencia na propagação, como medir seu impacto e quais as possíveis estratégias para controlar o processo de difusão. Nesta tese buscamos contribuir nas análises da interação entre as dinâmicas de propagação de informações e rumores e a estrutura da rede. Propomos um modelo de propagação mais realista considerando a heterogeneidade dos indivíduos na transmissão de ideias ou informações. Nós confirmamos a presença de propagadores mais influentes na dinâmica de rumor e observamos que é possível melhorar ou reduzir expressivamente a difusão de uma informação ao selecionar uma fração muito pequena de propagadores influentes. No caso em que se objetiva selecionar um conjunto de propagadores iniciais que maximizem a difusão de informação, a melhor opção é selecionar os indivíduos mais centrais ou importantes nas comunidades. Porém, se o padrão de conexão dos vértices está negativamente correlacionado, a melhor alternativa é escolher entre os indivíduos mais centrais de toda a rede. Por outro lado, através de abordagens topológicas e de técnicas de aprendizagem máquina, identificamos aos propagadores menos influentes e mostramos que eles atuam como um firewall no processo de difusão. Nós propomos um método adaptativo de reconexão entre os vértices menos influentes para um indivíduo central da rede, sem afetar a distribuição de grau da rede. Aplicando o nosso método em uma pequena fração de propagadores menos influentes, observamos um aumento importante na capacidade de propagação desses vértices e da rede toda. Nossos resultados vêm de uma ampla gama de simulações em conjuntos de dados artificiais e do mundo real e a comparação com modelos clássicos de propagação da literatura. A propagação da informação em redes é de grande relevância para as áreas de publicidade e marketing, educação, campanhas políticas ou de saúde, entre outras. Os resultados desta tese podem ser aplicados e estendidos em diferentes campos de pesquisa como redes biológicas e modelos de comportamento social animal, modelos de propagação de epidemias e na saúde pública, entre outros. / On-line Social networks become a new and important medium of exchange of information, ideas and communication that approximate relatives and friends no matter the distances. Given the open nature of the Internet, the information can flow very easy and fast in the population. The network can be represented as a graph, where individuals or organizations are the set of vertices and the relationship or connection among the vertices are the set of edge. Moreover, the social networks are also intrinsically representing the structure of a more complex system that is the society. These structures are related with characteristics of the subjects, like the most popular individuals have many connections, the correlation in the connectivity of vertices that is a trace of homophily phenomenon, among many others. In particular, it is well accepted that the structure of the network can affect the way the information propagates on the social networks. However, how the structure impacts in the propagation, how to measure that impact and what are the strategies for controlling the propagation of some information, it is still unclear. In this thesis, we seek to contribute in the analysis of the interplay between the dynamics of information and rumor spreading and the structure of the networks. We propose a more realistic propagation model considering the heterogeneity of the individuals in the transmission of ideas or information. We confirm the presence of influential spreaders in the rumor propagation process and found that selecting a very small fraction of influential spreaders, it is possible to expressively improve or reduce de diffusion of some information on the network. In the case we want to select a set of initial spreaders that maximize the information diffusion on the network, the simple and best alternative is to select the most central or important individuals from the networks communities. But, if the pattern of connection of the networks is negatively correlated, the best alternative is to choose from the most central individuals in the whole network. On the other hand, we identify, by topological approach and machine learning techniques, the least influential spreaders and show that they act as a firewall in the propagation process. We propose an adaptative method that rewires one edge for a given vertex to a central individual, without affecting the overall distribution of connection. Applying our proposed method in a little fraction of least influential spreaders, we observed an important increasing in the capacity of propagation of these vertices and in the overall network. Our results are from a wide range of simulations in artificial and real-world data sets and the comparison with the classical rumor propagation model. The propagation of information is of greatest relevance for publicity and marketing area, education, political or health campaigns, among others. The results of this these might be applicable and extended in different research fields like biological networks and animal social behavior models.

In this thesis the optical method of Near-Infrared-Spectroscopy (NIRS) is evaluated with regards to its capability of non-invasive detection of Leão´s cortical spreading depression (CSD) and spontaneous peri-infarct-depolarizations (PID). With the NIR-spectrometer NIRO 500 (Hamamatsu, Japan) regional cerebral oxy-genation (rCBO) changes were measured during CSD in 9, and during PID in 10 barbiturate anesthatized rats. The method if NIRS that relies on oxygen-dependent absorption changes of hemo-globin and cytochrome oxydase as well as the high penetrability of biologic tissues for light in the range between 700 and 1000 nm proved suitable to detect and to distinguish both CSD and PID experimentally. This distinction relies on the robust decrease of deoxy- and increase of oxyhemo-globin concentrations (i.e. a relative hyperoxemia) during CSD while PID is cha-racterized by an initial increase of deoxy- and decrease of oxyhemoglobin (relative hypooxemia). Despite the profound anatomical differences between gyrencephalic humans and lyssencephalic rats, the observed patterns of rCBO changes may guide the inter-pretation of future NIRS measurements in patients with migraines with aura (CSD) or stroke (PID). However, for concentration changes of oxydized cytochrome aa3 with its low con-centration compared to the hemoglobins, the pathophysiological interpretation of the data obtained with NIRO 500 is confounded by the limits of attenuation mea-surements at only four wavelengths. A validation of the cytochrome oxydase signal and an improved quantification of all concentration changes is highly desirable and may be achieved by employment of a continuous-wavelength device measuring the full spectral range of the near infrared. It would also allow to measure the mean optical pathlength in the highly scattering tissue and to correct for its physiologically occuring changes e.g. by measurements at the water absorption peak. Similar improvements would enhance the value of the method for further physiolo-gical and pathophysiological studies because NIRS provides the unique opportu-nity to obtain simultaneous data on blood oxygenation as well as the redox state of the mitochondrial cytochrome oxydase.

Une communication est impulsive chaque fois que le signal portant des informations est intermittent dans le temps et que la transmission se produit à rafales. Des exemples du concept impulsife sont : les signaux radio impulsifs, c’est-à-dire des signaux très courts dans le temps; les signaux optiques utilisé dans les systèmes de télécommunications; certains signaux acoustiques et, en particulier, les impulsions produites par le système glottale; les signaux électriques modulés en position d’impulsions; une séquence d’événements dans une file d’attente; les trains de potentiels neuronaux dans le système neuronal. Ce paradigme de transmission est différent des communications continues traditionnelles et la compréhension des communications impulsives est donc essentielle. Afin d’affronter le problème des communications impulsives, le cadre de la recherche doit inclure les aspects suivants : la statistique d’interférence qui suit directement la structure des signaux impulsifs; l’interaction du signal impulsif avec le milieu physique; la possibilité pour les communications impulsives de coder l’information dans la structure temporelle. Cette thèse adresse une partie des questions précédentes et trace des lignes indicatives pour de futures recherches. En particulier, nous avons étudié: un système d'accès multiple où les utilisateurs adoptent des signaux avec étalement de spectre par saut temporel (time-hopping spread spectrum) pour communiquer vers un récepteur commun; un système avec un préfiltre à l'émetteur, et plus précisément un transmit matched filter, également connu comme time reversal dans la littérature de systèmes à bande ultra large; un modèle d'interférence pour des signaux impulsifs. / A communication is impulsive whenever the information-bearing signal is burst-like in time. Examples of the impulsive concept are: impulse-radio signals, that is, wireless signals occurring within short intervals of time; optical signals conveyed by photons; speech signals represented by sound pressure variations; pulse-position modulated electrical signals; a sequence of arrival/departure events in a queue; neural spike trains in the brain. Understanding impulsive communications requires to identify what is peculiar to this transmission paradigm, that is, different from traditional continuous communications.In order to address the problem of understanding impulsive vs. non-impulsive communications, the framework of investigation must include the following aspects: the different interference statistics directly following from the impulsive signal structure; the different interaction of the impulsive signal with the physical medium; the actual possibility for impulsive communications of coding information into the time structure, relaxing the implicit assumption made in continuous transmissions that time is a mere support. This thesis partially addresses a few of the above issues, and draws future lines of investigation. In particular, we studied: multiple access channels where each user adopts time-hopping spread-spectrum; systems using a specific prefilter at the transmitter side, namely the transmit matched filter (also known as time reversal), particularly suited for ultrawide bandwidhts; the distribution function of interference for impulsive systems in several different settings.

O objetivo da tese foi visualizar como as imagens das cientistas podem estar contribuindo para a manutenção de um panorama predominantemente masculino na ciência, sobretudo nas ciências duras, em razão de estudiosos de gênero terem identificado discriminação sexista como causa da ausência delas na área. Para tal, usamos o suporte teórico da teoria das Representações Sociais de Moscovici para entender a representação de mulher cientista como fenômeno que se modifica através do tempo e as imagens como fatores intervenientes nesse processo de mudança. O esforço do pensamento humano no intuito de entender a visão e as imagens resultou em teorias para explicar as imagens físicas tangíveis, através da compreensão da luz como veículo para mediar as representações que a mente cria, em imagens mentais, por intermédio da captação das imagens físicas nos olhos. Estudamos então como a transformação dessas teorias, através do tempo, culminou no conceito de imagem da ciência moderna, resultado da busca de objetividade de uma ciência em transformação. A culminação paradigmática na ciência moderna criou condições para a naturalização das imagens fotográficas, e pós-fotográficas, como imagens verdadeiras, introduzindo-as como reais, conceito presente nas mentes atuais. Separamos, assim, as imagens em dois grupos: imagens mentais e imagens físicas, para estudar a participação das últimas nas transformações das primeiras; as imagens mentais são entendidas na concepção das representações sociais. Encontramos, assim, na divulgação científica as imagens aliadas às jornalísticas, de cientistas consideradas aqui como reais. Comparando-as com as das películas cinematográficas de ficção, observamos semelhanças e diferenças para concluir como elas interferem na representação da mulher que trabalha com ciência. Em levantamento das imagens, no período de aproximadamente dez anos, de 1996 a 2007, na divulgação cientifica, gênero literário adotado aqui como interface comunicativa entre a Ciência e o senso comum, vê-se que as representações veiculadas, em imagens e textos, têm se metamorfoseado. Na metade da década de 1990, entrevistas com mulheres cientistas enfocavam sua vida doméstica, ressaltando seu duplo pertencimento: privado e público. Atualmente os artigos têm o mesmo teor das entrevistas com cientistas do sexo masculino, focalizando apenas seu trabalho. Dando visibilidade apenas ao que julgam extraordinário, contudo, reforçam as representações sociais de ciência e de cientista como um ser incomum e superdotado, estereótipo já presente no imaginário do senso comum. O cinema reforça isso ao nos oferecer, ao olhar e à interpretação, imagens de cientistas em tramas verossímeis, porém como personagens cuja complexidade tornaas difíceis de serem espelhados como modelos para futuras cientistas. Dessa maneira, as duas mídias acabam se complementando no reforço de uma representação que perpetua o estado de exclusão das mulheres na ciência. Em lugar de dar visibilidade à Ciência como empreendimento e cientista como um trabalhador comprometido com seu labor, ambas as mídias contribuem para manutenção das coisas como estão: uma imagem que contempla o cientista como um ser superior e do sexo masculino, ainda que tenha se ampliado o número de cientistas mulheres. / This thesis objective is to visualize how women scientists images can contribute for the maintenance of a masculine gender panorama in science. This was identified especially on hard sciences, thanks to studies that found sex discrimination as a cause for scientists women absence. Therefore, we use as support the theory of the Social Representations of Moscovici to make clear the representation of woman scientist as phenomenon that modifies through the time, and images as intervening factors in this changing process. The effort of the human thought to understand the vision and the images, resulted in theories to explain the tangible physical images, through the comprehension of the light as a vehicle to mediate the representations that the mind creates, in mental images, by means of the physical images catching in the eyes. We study then, how the transformation of these theories, across the time, culminated in the concept of image in modern science, as a result of the search of objectivity in a mutant science. The paradigmatic culmination in modern science, created conditions for the naturalization of the photographic images, and post photographic, as \"true images\", introducing them as real, a present concept in the current minds. We separate, so, the images in two groups: mental images and physical images, to study the participation of the last ones into the transformations of the first ones; the mental images are understood in the conception of the social representations. We find then, in the scientific diffusion, the images allied to the journalistic ones, of scientists considered here as real. Comparing them with the ones of the fictions cinematographic films, we observe similarities and differences to conclude as they intervene in representation of the woman who works with science. In survey of the images, about the period of ten years, from 1996 to 2007, in the scientific spreading, the literary genre adopted here as communicative interface between Science and the common sense, it can be seen that the representations propagated in images and texts have metamorphosed. At the half of the decade of 1990, interviews with women scientists focused its domestic life, standing out its double belonging: private and public. Currently the papers have the same aspects of the interviews with scientists of the masculine sex, focusing only its work. They give visibility only to that they judge extraordinary, however, they strengthen the social representations of science and scientist as a uncommon and super endowed being, like a stereotype present in the imaginary mind of the common sense. The cinema reinforce it when offers us to see and make interpretation, images of scientists in likely trams, however as personages whose complexity becomes them difficult to be reflected as models for future scientists. By this way, the two medias complement themselves reinforcing a representation that perpetuates the state of exclusion to the women in science. Instead of giving visibility to Science as an achievement and to put the scientist as a worker compromised to its job, both the medias contribute for maintenance of the things as they are: a image that contemplates scientist like a superior being, even there is more women scientists nowadays.

"The present work is a study of the low inertia spreading dynamics of initially spherical viscous droplets on a planar interface. The droplets are affected by gravity, surface tension and viscous forces and are modeled as two-dimensional axisymmetric bodies. The main focus of this study is the examination of the dependence of droplet stability, equilibrium shape and fluid motion within the drop on the relative magnitude of these forces. The dynamics are modeled using the unsteady, non-linear Navier-Stokes equations for an incompressible fluid. The spreading of a droplet on a solid surface is modeled with both a no-slip and a partial-slip boundary condition. In addition, the spreading of a droplet on another identical drop (two-drop problem) is modeled to study the problem without the contact point singularity. The governing equations are solved numerically using the Mixed Galerkin Finite Element formulation, augmented by the use of the Newton-Raphson iteration scheme to effectively treat the non-linearities of the problem. The Generalized Eulerian Lagrangian formulation is adopted for the treatment of the moving free surface of the droplet. Computations are performed for capillary numbers ranging from 0.01 to 100 and for Reynolds numbers from 0.005 to 50, where the velocity scale is based on the droplet radius and the gravitational acceleration. For the droplet spreading on a solid surface, three distinct behaviors are observed~: for low Reynolds numbers and sufficiently high capillary numbers, droplets deform to a stable, equilibrium shape; for higher Reynolds numbers, an oscillatory droplet behavior occurs; at still higher Reynolds numbers, the droplets shatter. Very often, a recirculation is induced near the contact point just before the droplet shatters, which is also observed for the case of stable oscillating droplets. When a partial-slip boundary condition is applied, it is observed that the stability of the droplet and the rate at which the droplet attains the static contact angle depend strongly on the velocity of slip of the droplet with respect to the solid surface at the contact point. For the two-drop problem, only two distinct behaviors are observed: for low Reynolds numbers and high capillary numbers, the droplet retains a near-spherical shape and remains stable; while for higher Reynolds numbers, the droplet deforms to a high extent and becomes unstable."

"Photonic crystals have recently been the subject of studies for use in optical signal processing. In particular, a Coupled Resonator Optical Waveguide (CROW) structure has been considered by M. F. Yanik and S. Fan in “Stopping Light All Optically” for use in a time-varying optical system for the storage of light in order to mitigate the effects of waveguide dispersion. In this thesis, the effects of the thermal field on the state stored in such a structure is studied. Through simulation, this thesis finds that when this structure is constructed of gallium arsenide cylinders in air, loss of the signal was found to be caused by free-carrier absorption, and the decay of the signal dominates over thermal spreading of the optical signal’s spectrum."