abstract: The Culture-Language Interpretive Matrix (C-LIM) is a new tool hypothesized to help practitioners accurately determine whether students who are administered an IQ test are culturally and linguistically different from the normative comparison group (i.e., different) or culturally and linguistically similar to the normative comparison group and possibly have Specific Learning Disabilities (SLD) or other neurocognitive disabilities (i.e., disordered). Diagnostic utility statistics were used to test the ability of the Wechsler Intelligence Scales for Children-Fourth Edition (WISC-IV) C-LIM to accurately identify students from a referred sample of English language learners (Ells) (n = 86) for whom Spanish was the primary language spoken at home and a sample of students from the WISC-IV normative sample (n = 2,033) as either culturally and linguistically different from the WISC-IV normative sample or culturally and linguistically similar to the WISC-IV normative sample. WISC-IV scores from three paired comparison groups were analyzed using the Receiver Operating Characteristic (ROC) curve: (a) Ells with SLD and the WISC-IV normative sample, (b) Ells without SLD and the WISC-IV normative sample, and (c) Ells with SLD and Ells without SLD. Results of the ROC yielded Area Under the Curve (AUC) values that ranged between 0.51 and 0.53 for the comparison between Ells with SLD and the WISC-IV normative sample, AUC values that ranged between 0.48 and 0.53 for the comparison between Ells without SLD and the WISC-IV normative sample, and AUC values that ranged between 0.49 and 0.55 for the comparison between Ells with SLD and Ells without SLD. These values indicate that the C-LIM has low diagnostic accuracy in terms of differentiating between a sample of Ells and the WISC-IV normative sample. Current available evidence does not support use of the C-LIM in applied practice at this time. / Dissertation/Thesis / Ph.D. Educational Psychology 2012

In order to support the new paradigm shift in fifth generation (5G) mobile communication, radically different network architectures, associated technologies and network operation algorithms, need to be developed compared to existing fourth generation (4G) cellular solutions. The evolution toward 5G mobile networks will be characterized by an increasing number of wireless devices, increasing device and service complexity, and the requirement to access mobile services ubiquitously. To realise the dramatic increase in data rates in particular, research is focused on improving the capacity of current, Long Term Evolution (LTE)-based, 4G network standards, before radical changes are exploited which could include acquiring additional spectrum. The LTE network has a reuse factor of one; hence neighbouring cells/sectors use the same spectrum, therefore making the cell-edge users vulnerable to heavy inter cell interference in addition to the other factors such as fading and path-loss. In this direction, this thesis focuses on improving the performance of cell-edge users in LTE and LTE-Advanced networks by initially implementing a new Coordinated Multi-Point (CoMP) technique to support future 5G networks using smart antennas to mitigate cell-edge user interference in uplink. Successively a novel cooperative uplink inter-cell interference mitigation algorithm based on joint reception at the base station using receiver adaptive beamforming is investigated. Subsequently interference mitigation in a heterogeneous environment for inter Device-to-Device (D2D) communication underlaying cellular network is investigated as the enabling technology for maximising resource block (RB) utilisation in emerging 5G networks. The proximity of users in a network, achieving higher data rates with maximum RB utilisation (as the technology reuses the cellular RB simultaneously), while taking some load off the evolved Node B (eNodeB) i.e. by direct communication between User Equipment (UE), has been explored. Simulation results show that the proximity and transmission power of D2D transmission yields high performance gains for D2D receivers, which was demonstrated to be better than that of cellular UEs with better channel conditions or in close proximity to the eNodeB in the network. It is finally demonstrated that the application, as an extension to the above, of a novel receiver beamforming technique to reduce interference from D2D users, can further enhance network performance. To be able to develop the aforementioned technologies and evaluate the performance of new algorithms in emerging network scenarios, a beyond the-state-of-the-art LTE system-level-simulator (SLS) was implemented. The new simulator includes Multiple-Input Multiple-Output (MIMO) antenna functionalities, comprehensive channel models (such as Wireless World initiative New Radio II i.e. WINNER II) and adaptive modulation and coding schemes to accurately emulate the LTE and LTE-A network standards.

The Top Scoring Pair (TSP) classifier, based on the notion of relative ranking reversals in the expressions of two marker genes, has been proposed as a simple, accurate, and easily interpretable decision rule for classification and class prediction of gene expression profiles. We introduce the AUC-based TSP classifier, which is based on the Area Under the ROC (Receiver Operating Characteristic) Curve. The AUCTSP classifier works according to the same principle as TSP but differs from the latter in that the probabilities that determine the top scoring pair are computed based on the relative rankings of the two marker genes across all subjects as opposed to for each individual subject. Although the classification is still done on an individual subject basis, the generalization that the AUC-based probabilities provide during training yield an overall better and more stable classifier. Through extensive simulation results and case studies involving classification in ovarian, leukemia, colon, and breast and prostate cancers and diffuse large b-cell lymphoma, we show the superiority of the proposed approach in terms of improving classification accuracy, avoiding overfitting and being less prone to selecting non-informative pivot genes. The proposed AUCTSP is a simple yet reliable and robust rank-based classifier for gene expression classification. While the AUCTSP works by the same principle as TSP, its ability to determine the top scoring gene pair based on the relative rankings of two marker genes across {\em all} subjects as opposed to each individual subject results in significant performance gains in classification accuracy. In addition, the proposed method tends to avoid selection of non-informative (pivot) genes as members of the top-scoring pair.\\ We have also proposed the use of the AUC test statistic in order to reduce the computational cost of the TSP in selecting the most informative pair of genes for diagnosing a specific disease. We have proven the efficacy of our proposed method through case studies in ovarian, colon, leukemia, breast and prostate cancers and diffuse large b-cell lymphoma in selecting informative genes. We have compared the selected pairs, computational cost and running time and classification performance of a subset of differentially expressed genes selected based on the AUC probability with the original TSP in the aforementioned datasets. The reduce sized TSP has proven to dramatically reduce the computational cost and time complexity of selecting the top scoring pair of genes in comparison to the original TSP in all of the case studies without degrading the performance of the classifier. Using the AUC probability, we were able to reduce the computational cost and CPU running time of the TSP by 79\% and 84\% respectively on average in the tested case studies. In addition, the use of the AUC probability prior to applying the TSP tends to avoid the selection of genes that are not expressed (``pivot'' genes) due to the imposed condition. We have demonstrated through LOOCV and 5-fold cross validation that the reduce sized TSP and TSP have shown to perform approximately the same in terms of classification accuracy for smaller threshold values. In conclusion, we suggest the use of the AUC test statistic in reducing the size of the dataset for the extensions of the TSP method, e.g. the k-TSP and TST, in order to make these methods feasible and cost effective.

Cooperative and cognitive radio systems have been proposed as a solution to improve the quality-of-service (QoS) and spectrum efficiency of existing communication systems. The objective of this dissertation is to propose and analyze schemes for cooperative and cognitive radio systems considering real world scenarios and to make these technologies implementable. In most of the research on cooperative relaying, it has been assumed that the communicating nodes have perfect channel state information (CSI). However, in reality, this is not the case and the nodes may only have an estimate of the CSI or partial knowledge of the CSI. Thus, in this dissertation, depending on the amount of CSI available, novel receivers are proposed to improve the performance of amplify-and forward relaying. Specifically, new coherent receivers are derived which do not perform channel estimation at the destination by using the received pilot signals directly for decoding. The derived receivers are based on new metrics that use distribution of the channels and the noise to achieve improved symbol-error-rate (SER) performance. The SER performance of the derived receivers is further improved by utilizing the decision history in the receivers. In cases where receivers with low complexity are desired, novel non-coherent receiver which detects the signal without knowledge of CSI is proposed. In addition, new receivers are proposed for the situation when only partial CSI is available at the destination i.e. channel knowledge of either the source-relay link or the relay-destination link but not both, is available. These receivers are termed as `half-coherent receivers' since they have channel-state-information of only one of the two links in the system. In practical systems, the CSI at the communicating terminals becomes outdated due to the time varying nature of the channel and results in system performance degradation. In this dissertation, the impact of using outdated CSI for relay selection on the performance of a network where two sources communicate with each other via fixed-gain amplify-and-forward relays is studied and for a Rayleigh faded channel, closed-form expressions for the outage probability (OP), moment generating function (MGF) and SER are derived. Relay location is also taken into consideration and it is shown that the performance can be improved by placing the relay closer to the source whose channel is more outdated. Some practical issues encountered in cognitive radio systems (CRS) are also investigated. The QoS of CRS can be improved through spatial diversity which can be achieved by either using multiple antennas or exploiting the independent channels of each user in a multi-user network. In this dissertation, both approaches are examined and in multi-antenna CRS, transmit antenna selection (TAS) is proposed where as in a multi-user CRS, user selection is proposed to achieve performance gains. TAS reduces the implementation cost and complexity and thus makes CRS more feasible. Additionally, unlike previous works, in accordance with real world systems, the transmitter is assumed to have limited peak transmit power. For both these schemes, considering practical channel models, closed-form expression for the OP performance, SER performance and ergodic capacity (EC) are obtained and the performance in the asymptotic regimes is also studied. Furthermore, the OP performance is also analyzed taking into account the interference from the primary network on the cognitive network.

L’orbite d’un satellite autour de la terre est perturbée en permanence par différents facteurs, tels que la variation du champ gravitationnel et la pression du vent solaire. La dérive de la position du satellite peut compromettre la mission, voire mener à une collision ou à une chute dans l’atmosphère. Les opérations de maintien à poste consistent donc à effectuer une mesure précise de la trajectoire du satellite puis à utiliser ses propulseurs pour corriger sa dérive. La solution classique de mesure de position est basée sur des radars au sol. Ce dispositif est couteux et ne permet pas d’avoir la position du satellite en permanence : les corrections de trajectoires se font donc de façon espacées dans le temps.Un système de positionnement et de navigation autonome utilisant les constellations de satellites de navigation, appelées Global Navigation Satellite System (GNSS), permettrait une réduction importante des coûts de conception et de maintenance opérationnelle. Plusieurs études ont été menées en ce sens et les premiers systèmes de navigation, basés sur des récepteurs GPS, voient le jour. Un récepteur en mesure de traiter plusieurs systèmes de navigation, tel que GPS et Galileo, permettrait d’obtenir une meilleure disponibilité de service. En effet, le système Galileo est conçu pour être compatible avec le système GPS,tant en terme de signaux émis que de données de navigation. La connaissance permanente de la position permettrait alors de réaliser un contrôle asservit du maintien à poste.Dans un premier temps, nous avons défini quelles seront les spécifications d’un récepteur spatial multi-mission.En effet, les contraintes pesant sur un tel récepteur sont différentes de celles d’un récepteur situé à la surface de la Terre. L’analyse de ces contraintes, ainsi que des performances demandées à un système de positionnement, est donc nécessaire afin de déterminer les spécifications du futur récepteur. Il existe peu d’études sur le sujet. Certaines d’entre elles sont classées secret industriel, d’autres présentent, à notre avis,un biais d’analyse qui fausse la détermination des spécifications.Nous avons donc modélisé le système : orbites des satellites GNSS et des satellites récepteurs, liaison radiofréquence. Certains paramètres de cette liaison ne sont pas donnés dans les documents de spécifications ou les documents constructeurs. De plus, les données théoriques disponibles ne sont pas toujours pertinentes pour une modélisation réaliste. Nous avons donc dû estimer ces paramètres en utilisant des données disponibles.Le modèle a été ensuite utilisé afin de simuler divers scenarii représentatifs de futures missions. Après avoir défini des critères d’analyse, les spécifications ont été déterminées à partir des résultats des simulations.Le calcul d’une position par un système de navigation par satellite se déroule en trois phases principales.Pour chacune de ces phases, il existe plusieurs algorithmes possibles, présentant des caractéristiques différentes de performance, de taille de circuit ou de charge de calcul. L’essor de nouvelles applications basées sur la navigation entraine également le développement de nouveaux algorithmes adaptés.Nous présentons le principe permettant la détermination d’une position, puis les signaux de navigation GPS et Galileo. A partir de la structure des signaux, nous expliquons les phases de la démodulation et de la localisation. Grâce à l’utilisation des constellations GPS et Galileo, les algorithmes standards permettent d’atteindre les performances nécessaires pour des applications spatiales. Ces algorithmes nécessitent néanmoins d’être adaptés ; ainsi certaines parties ont été conçues spécifiquement. Afin de valider les choix d’algorithmes, et les paramètres liés aux spécifications, nous avons simulés les différentes phases de fonctionnement du récepteur en utilisant des signaux GPS réels.Pour terminer, les retombées et perspectives sont exposées dans la conclusion. / The orbit of a satellite around the earth is constantly disturbed by various factors, such as variations in the gravitational field and the solar wind pressure. The drift of the satellite position can compromise the mission, and even lead to a crash or a fall in the atmosphere. The station-keeping operations therefore consist in performing an accurate measurement of the satellite trajectory and then in using its thrusters to correct the drift. The conventional solution is to measure the position with the help of a ground based radar. This solution is expensive and does not allow to have the satellite position permanently: the trajectory corrections are therefore in frequent. A positioning and autonomous navigation system using constellations of navigation satellites, called Global Navigation Satellite System (GNSS), allows a significant reduction in design and operational maintenance costs. Several studies have been conducted in this direction and the first navigation systems based on GPS receivers, are emerging. A receiver capable of processing multiple navigation systems, such as GPS and Galileo, would provide a better service availability. Indeed, Galileo is designed to be compatible with GPS, both in terms of signals and navigation data. Continuous knowledge of the position would then allow a closed loop control of the station keeping. Initially, we defined what the specifications of a multi-mission space receiver are. Indeed, the constraints on such a receiver are different from those for a receiver located on the surface of the Earth. The analysis of these constraints, and the performance required of a positioning system, is necessary to determine the specifications of the future receiver. There are few studies on the subject. Some of them are classified; others have, in our view, an analytical bias that distorts the determination of specifications. So we modeled the system: GNSS and receivers satellite orbits, radio frequency link. Some parameters of this link are not given in the specification or manufacturers documents. Moreover, the available theoretical data are not always relevant for realistic modeling. So we had to assess those parameters using the available data. The model was then used to simulate various scenarios representing future missions. After defining analysis criteria, specifications were determined from the simulation results. Calculating a position of a satellite navigation system involves three main phases. For each phase, there are several possible algorithms, with different performance characteristics, the circuit size or the computation load. The development of new applications based on navigation also drives the development of new adapted algorithms. We present the principle for determining a position, as well as GPS and Galileo navigation signals. From the signal structure, we explain the phases of the demodulation and localization. Through the use of GPS and Galileo constellations, standard algorithms achieve the performance required for space applications. However, these algorithms need to be adapted, thus some parts were specifically designed. In order to validate the choice of algorithms and parameters, we have simulated the various operating phases of the receiver using real GPS signals. Finally, impact and prospects are discussed in the conclusion.

Mes travaux de thèse portent sur l'échantillonnage direct du signal RF en réception après l'antenne, dans un contexte d'applications radio-logicielle et radio-cognitive. Le but de cette technique est de pouvoir traiter le signal quelle que soit la modulation utilisée et dans une large gamme de fréquences, directement après l'antenne, en réduisant au maximum la partie analogique. Pour cela une architecture d'échantillonneur passif a été utilisée. L'originalité de cette architecture consiste en l'implémentation d'un système d'échantillonnage différentiel en quadrature purement passif, constitué d'un réseau de capacités commutées. En fixant la constante de temps du système à une valeur élevée devant la fréquence minimale du signal RF à démoduler, l'échantillonneur se comporte à la fois en tant que mélangeur et filtre en fréquence. Cela permet la réjection des brouilleurs hors de la bande de réception et contribue à améliorer sensiblement la dynamique du système de réception, le tout pour une consommation très faible. Aussi, le système est flexible en fréquence, permettant ainsi de recevoir le spectre RF sur une large bande et de recevoir différents types de signaux modulés. Celui-ci a été intégré dans un front-end de réception complet en technologie CMOS 130nm pour des applications dans les bandes ISM (433MHz et 868MHz) dont les débits de transmission sont limités à 1Mbits/s. L'architecture développée est adaptée à des applications de type radio-logicielle ou radio-cognitive, lorsqu'une agilité en fréquence, une grande dynamique et des contraintes de consommation très basse sont visées. / My thesis work is focusing on the RF signal direct sampling reception after the antenna in a software-defined radio applications and cognitive radio context. The purpose of this technique is to treat the signal whatever the modulation used and in a wide range of frequencies, directly after the antenna while minimizing at maximum the analog part. For this, a passive sampler architecture has been used. The originality of this architecture consists in the implementation of a passive differential sampling system working in quadrature, consisting of a switched capacitors network. By setting the time system constant to a high value compared to the minimum frequency of the RF signal to be demodulated , the sampler acts both as a filter and a frequency mixer. This allows the rejection of interferers outside the reception band and contributes to improve significantly the receiver system dynamic, for a very low consumption. Also, the system is flexible in frequency, which permits to receive the RF spectrum over a wide band of frequencies and detect different types of modulated transmitted signals. It has been integrated into a complete front-end 130nm CMOS technology receiver dedicated to ISM bands applications (433MHz and 868MHz bands) whose transmission data rates are limited to 1Mbit/s. The developed architecture is suitable for software-defined radio or cognitive radio applications where frequency agility, high dynamic and very low power constraints are targeted.

O melanoma malígno está entre os cânceres que mais têm aumentado nas últimas décadas representando um grande desafio terapêutico. Quando diagnosticado precocemente, as chances de cura por excisão cirúrgica com margens de segurança adequadas são altas. Entretanto, casos avançados de melanoma são resistentes às formas atuais de terapia; assim, um dos maiores desafios para a pesquisa em melanoma é a identificação de alvos moleculares para o desenvolvimento de novas estratégias de tratamento. A capacidade de impedir o desenvolvimento de um tumor depende do melhor entendimento das vias celulares e moleculares que operam no microambiente tumoral. Uma inflamação crônica e persistente contribui para o desenvolvimento do câncer, e mesmo tumores que não são epidemiologicamente ligados a patógenos, são caracterizados pela presença de componentes inflamatórios em seu microambiente. O Sistema Calicreínas-Cininas (SCC) é responsável por uma série de efeitos biológicos, como vasodilatação, modulação da dor e inflamação, contração/relaxamento da musculatura lisa e efeitos sobre a proliferação celular. A participação do receptor B1 de cininas é bem relacionada a processos inflamatórios; contudo, a relação entre o SCC e câncer ainda é pouco descrita na literatura. Com relação ao melanoma, não existem na literatura, estudos que relacionam a participação do SCC e essa patologia. Portanto, a identificação de mecanismos genéticos e de vias de sinalização que levam à formação e progressão tumoral é de extrema importância para um desenho racional de terapias. Assim, o objetivo desse trabalho foi estudar a participação do receptor B1 de cininas no desenvolvimento de melanoma. Primeiramente realizou-se ensaios in vitro com células de melanoma murino, B16F10, verificando-se a presença dos componentes do SCC nesta linhagem celular, bem como a capacidade de migração das células quando estimuladas com o agonista e antagonista do receptor B1. Posteriormente, induziu-se melanoma em animais selvagens e knockout para o receptor B1 e verificou-se expressão de citocinas, vias de proliferação e apoptose e vascularização nesses tumores a partir técnicas de PCR, western blotting e análise histológica. Observou-se que células B16F10 estimuladas com o agonista do receptor B1, diminuem a capacidade de migração. Tumores desenvolvidos em animais knockout para o receptor B1, possuem uma menor expressão gênica desse receptor quando comparados com tumores desenvolvidos em animais selvagens e apresentam vias de proliferação celular mais ativadas, além de uma vascularização irregular. Considerando esses resultados, sugerimos que o receptor B1 de cininas contribui para o impedimento da progressão tumoral, podendo, futuramente, ser um alvo terapêutico para o tratamento de melanoma. / Malignant melanoma is between the cancer types that most have been increased in the last decades, representing a therapeutic challenge. When it is early detected, chances of cure through surgical excisions with secure margins are high. However, advanced cases of melanoma are resistant to all types of therapies; thus, one of the most challenges for research in melanoma is the identification of molecular targets to further develop new strategies of treatment. The ability to blockade the development of a tumor depends on a better understanding of cellular and molecular pathways that operate in the tumor microenvironment. A chronic and persistent inflammation contributes to cancer development, and, even tumors that are not epidemiologically linked to pathogens present inflammatory components in their microenvironment. The Kallicrein-Kinin System (KKS) is responsible for several biological effects, like, vasodilatation, modulation of pain and inflammation, contraction/relaxation of smooth muscles and cell proliferation. The kinin B1 receptor is well related to inflammatory processes, however, the involvement of the KKS in cancer development is, yet, not well described in the literature. Regarding to melanoma, studies relating the involvement of the KKS in melanoma development is still not available. This way, identification of genetic mechanisms and signaling pathways that drive melanoma formation and progression is extremely important for designing rational therapies in the future. Thus, the aim of this study was evaluate the participation of the kinin B1 receptor in melanoma progression. First, in vitro assays with murine melanoma cells, B16F10, were performed to verify the presence of the KKS components in this cell lineage, as well as the capacity of migration when these cells are stimulated with the B1 receptor agonist and antagonist. Then, melanoma was induced in wild type and B1 receptor knockout mice and the expression of cytokines, proliferation and apoptosis pathways and vascularization were studied by PCR, western blotting and histological analyses. We observed that B16F10 cells stimulated with the B1 receptor agonist had their capacity of migration decreased. Tumors developed in B1 receptor knockout mice showed a lower expression of this gene comparing to the tumors developed in wild type animals, also presenting higher activation of proliferation pathways and abnormal vessels. Considering these results, we suggest that the kinin B1 receptor contributes to blockade, at least in part, the tumor progression which can, in the future, become a therapeutic target for melanoma treatment.

Made available in DSpace on 2015-04-22T22:00:44Z (GMT). No. of bitstreams: 1 Fabio Souza.pdf: 2048954 bytes, checksum: eefa7e9a921c2d464387c806011b4a79 (MD5) Previous issue date: 2012-01-11 / The development of interactive content for digital TV systems involves a process that requires the use of several tools, among which stand out tools for editing, multiplexing, and presenting interactive content. When developing interactive applications for portable devices, such as cell phones, it is important to consider unique characteristics of those presentation environments, which may vary between different screen sizes, different data input mechanisms, support for interactive channel, among others. The research conducted in this study focused on presentation environments for interactive applications designed to run on portable receivers in accordance with the Brazilian Digital TV System. The proposed simulator, Simulador Ginga-NCL para Dispositivos Portáteis (SGDP) -- Ginga-NCL Simulator for Handhelds Devices -- includes essential features necessary for simulating a interactive application presentation environment. Tuning oneseg TV signal, extraction of interactive content from transport stream, Lua scripts interpretation, and NCL applications presentation control, are examples of essential features contemplated by SGDP. Additionally, the proposed simulator logs information about the processing and presentation of interactive content for further analysis by developers. The Symbian platform was chosen for implementation of SGDP, and systemic tests were performed to validate the tool. / O desenvolvimento de conteúdo interativo para sistemas de TV digital envolve um processo que requer o uso de diversas ferramentas; dentre as quais se destacam: ferramentas de edição, multiplexação, e apresentação de conteúdo interativo. Ao desenvolver aplicações interativas destinadas a dispositivos portáteis, tais como telefones celulares, é importante levar em consideração características particulares destes ambientes de apresentação, as quais podem variar entre dimensões de telas distintas, mecanismos de entrada de dados no sistema, suporte a canal de interatividade, dentre outros. A pesquisa realizada neste trabalho concentrou-se em ambientes de apresentação de aplicações interativas destinadas a receptores portáteis em conformidade com o Sistema Brasileiro de TV Digital. O simulador proposto, Simulador Ginga-NCL para Dispositivos Portáteis (SGDP), contempla funcionalidades essenciais, necessárias para simulação de um ambiente de apresentação de aplicações interativas. Sintonia do sinal de TV oneseg, extração de conteúdos interativos do fluxo de transporte, interpretação de scripts Lua, e controle de apresentação de aplicações NCL, são exemplos de funcionalidades essenciais contempladas pelo SGDP. Adicionalmente, o simulador proposto registra informações sobre o processamento, e apresentação, de conteúdos interativos para análise posterior por desenvolvedores. A plataforma Symbian foi escolhida para implantação do SGDP, e testes sistêmicos foram realizados para validação da ferramenta.

Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-07-15T15:28:00Z No. of bitstreams: 1 Dissertação - Luiz Filipe da Silva Souza Pinto.pdf: 1522640 bytes, checksum: a54871524028e554440a39db821f0f39 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-20T14:41:25Z (GMT) No. of bitstreams: 1 Dissertação - Luiz Filipe da Silva Souza Pinto.pdf: 1522640 bytes, checksum: a54871524028e554440a39db821f0f39 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-20T14:44:33Z (GMT) No. of bitstreams: 1 Dissertação - Luiz Filipe da Silva Souza Pinto.pdf: 1522640 bytes, checksum: a54871524028e554440a39db821f0f39 (MD5) / Made available in DSpace on 2015-07-20T14:44:33Z (GMT). No. of bitstreams: 1 Dissertação - Luiz Filipe da Silva Souza Pinto.pdf: 1522640 bytes, checksum: a54871524028e554440a39db821f0f39 (MD5) Previous issue date: 2012-12-23 / Não Informada / Digital TV is increasingly present in the lives of Brazilians, because year after year, a large number of people are migrating from analog to digital as the analog system has a date for its shutdown. With the advancement of digital TV, you may notice significant improvements in audio and video technology used, it is also possible to establish an interaction between the viewer and the TV receiver device. In Brazil, this interaction occurs through the Ginga middleware technology developed by Brazilian researchers to standardize the interactive content sent to devices able to interpret it. In addition to televisions, another popular device is the mobile phone, which is present in a significant way across the country. The technology adopted by Brazil for the digital transmission of television signals, allows the phone to receive programming dedicated to portable devices in open and free way. The phone has a certain advantage over television due to its connectivity. Once the mobile phone is on most of the time connected to a telephone network, and may be 2G, 2.5G, 3G and 4G in the near future, while the television set is for the most part of the time offline (disconnected). This work presents a proposal to use the SMS service as interactive channel, also known as the return channel, for portable reception. This service is present in all mobile phones, and therefore may contribute to the popularization of the use of digital TV technology in the country. / A TV digital está cada vez mais presente na vida dos brasileiros, pois ano após ano, um número grande de pessoas está migrando do sistema analógico para o digital, uma vez que o sistema analógico tem data certa para seu encerramento. Com o avanço da TV digital, é possível notar melhoras significativas nas tecnologias de áudio e vídeo usadas, como também é possível estabelecer uma interação entre o telespectador e o dispositivo receptor. No Brasil, tal interação ocorre através do middleware Ginga, tecnologia desenvolvida por pesquisadores brasileiros para padronizar o conteúdo interativo enviado aos dispositivos capazes de interpretá-lo. Além dos televisores, outro dispositivo bastante popular é o telefone celular, que está presente de forma expressiva ao longo do país. A tecnologia adotada pelo Brasil para transmissão digital do sinal de TV, permite que o telefone celular receba a programação dedicada a dispositivos portáteis de formaaberta e gratuita. O telefone celular possui uma certa vantagem em relação ao aparelho de televisão no quesito conectividade. Uma vez que o telefone celular está na maior parte do tempo conectado a uma rede de telefonia, podendo ser 2G, 2.5G, 3G e em um futuro próximo 4G, enquanto que o aparelho de televisão está em sua maior parte do tempo offline (desconectado). Este trabalho apresenta uma proposta para o uso do serviço de SMS como canal de interatividade, também conhecido como canal de retorno, para recepção portátil. Este serviço está presente em todos os telefones celulares, e por isso, pode contribuir para a popularização do uso da tecnologia de TV digital no país.

Abstract High radio capacity is one of the main targets in wireless network planning. The characteristics of the broadband radio channel pose serious challenges for achieving this goal. This thesis views the capacity problem from two frameworks. In the first, the effective user capacity in advanced direct sequence wideband code-division multiple-access (DS-CDMA) radio networks is evaluated. Sensitivity to various imperfections in key system parameters is studied. The analysis is based on a mathematical foundation that presents complex signal models and enables evaluation of the performance losses due to parameter estimation errors and multipath fading. The effective number of users supported in a cell is restricted by the multiple access interference (MAI) in the same cell (intracell interference) and overall background noise. The studied wideband CDMA receiver structures comprise conventional rake receivers with both the maximal ratio combining (MRC) and equal gain combining (EGC) schemes that can be supplemented with either linear decorrelating or nonlinear successive cancellation-based multiuser detectors and M-antenna spatial diversity. The second framework focuses on direct sequence spread spectrum-based ultra wideband (UWB) indoor communications. Cochannel interference limited capacity is evaluated against the outage probability criterion in exponentially decaying lognormal multipath fading channels. Distance-dependence and spatial distribution of users is taken into account at different spatial cell configurations. Only moderate complexity partial rake receivers with noncoherent combining are employed. Total interference is composed of interpath, multipath, intracell, and intercell interference contributions. Lognormal sum approximations and simulations are used to evaluate distributions of the desired and interfering signals. The impact of the timing errors at the receiver monopulse correlation is studied. The numerical results for the wideband CDMA framework show that effective user capacity and sensitivity depend critically on the joint impact of nonidealities in system parameters (e.g., channel profile, severity of fading, receiver algorithms). User capacities of the studied multiuser enhanced receivers were more prone to these impairments than those of the simpler single user receivers. The results should be used for network planning and optimization. The numerical results of the UWB framework suggest that, even in the multipath rich channel, the optimal number of rake fingers can be less than half of the significant multipaths. Differences between circular, square, and hexagonal cell models proved to be minor with respect to link distance distributions. The derived link distance statistics are useful tools in the analytic piconet dimensioning and optimization.