Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Ray T. Chen. Vita. Includes bibliographical references.

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliography.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed on September 12, 2006). PDF text of dissertation: 149 p. : ill. ; 0.72Mb. UMI publication number: AAT 3209965. Includes bibliographical references. Also available in microfilm and microfiche format.

Thesis (Ph. D.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Electrical & Computer Engineering, 2005. / Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Genetically identical cells show a heterogeneous response to a multitude of signals such as growth factors and DNA damage. While this heterogeneity has been shown to be a major determinant of treatment success in several diseases including cancer, little is known about how differences in biochemical signalling networks underlie such heterogeneity. State-of-the-art methodologies to study biochemical networks are often invasive and enable to quantify biochemical events only on cell populations or at a single point in time for a single cell, and therefore, cannot adequately quantify the fast, asynchronous and heterogeneous responses. In order to address these limitations, we have developed a unique sensing platform based on fluorescence lifetime imaging microscopy (FLIM) capable to multiplex at least three biosensors by utilizing Förster Resonance Energy Transfer (FRET) efficiently. After an overall introduction in Chapter 1, I describe the rational design and characterization of novel FRET pairs aiming to utilize the visible spectrum efficiently in combination with FLIM in Chapter 2. We combined blue, green and red donor fluorescent proteins that are excited at the same wavelength (840 nm for two-photon excitation) with genetically encoded quenchers, i.e. non-fluorescent chromoproteins as acceptors. This sensing platform enables the simultaneous detection of three biochemical reactions within single living cells providing new opportunities to characterize and understand non-genetic heterogeneity. In Chapter 3, I will demonstrate the first application of this novel platform by studying the activity of three key enzymes in DNA damage-induced cell death, caspase-2, -3, and -9. We confirm the heterogeneous nature of Cisplatin-induced cell death in genetically identical cells but reveal the existence of at least three subpopulations of cells characterized by distinct caspase dynamics. By combining biochemical and morphological information we infer the existence of different biochemical network topologies that are associated with alternative death phenotypes each cell adopts, such as apoptosis and programmed necrosis. Finally, deconvolution of cellular populations and direct measurement of a three-node caspase network - formerly impossible - permitted us to design perturbations of cell fate choices utilizing clinically relevant inhibitors. These perturbations resulted in changes in cell fate in response to Cisplatin, a clinically desirable outcome that suggests new avenues for combinatorial drugging and a new strategy to reveal cancer vulnerabilities that may be otherwise confounded by typical genetic and non-genetic heterogeneity.

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2005 / With the growth of the personal computer industry, a number of households now contain two or more personal computers. The need to share resources such as printers, scanners and other PC peripherals has become evident. Communication between personal computers and other smart devices in the home is also required. This brings the emergence of home networking together with home automation. Home networking is the collection of elements to enable the connection and integration of multiple computing, control and communication devices. There are various options at this stage for home networking. One of the broadband options is indoor power line communication. The aim of the project was to evaluate a communication system capable of performing efficiently in South African Home Power line environment. In designing a communication system capable of performing in the harsh conditions which are presented in the home environment (noise, attenuation, phase distortion, etc.), a mathematical model that is representative of a typical suburban South African home power line is required. To aid the modeling process, an experimental network was constructed so measurements could be taken in a controlled environment. In conjunction with simulation, the model of the home power line network has aided the design of the data communication system. The project has involved: • Determining optimal specifications for the communication system. • Development of a home power line model representative of a typical South African suburban home environment. • Construction and measurement of an experimental power grid • Development of methods, algorithms and programs for the design of an OFDM PLC modem (in software) to optimal specifications. • Simulation development in MA1LAB of the OFDM Modem. • Comparison of different OFDM sub-modulation schemes for enhancing the communication system performance, In conclusion, the simulation model of the PLC modem correlates well with typical practical systems. Optimising throughput of the communication system and hardware development of the modem will form the basis for further research.

Orientador: Shusaburo Motoyama / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-12T15:24:08Z (GMT). No. of bitstreams: 1 Campos_CarlosFieldede_M.pdf: 874818 bytes, checksum: 0a93b48880d342d34a7fa00fb9bbad46 (MD5) Previous issue date: 2008 / Resumo: Neste estudo são avaliados o desempenho e o impacto do tráfego de voz em uma rede IP. Na rede IP o sinal de voz é transmitido através de pacotes que são identificados por um conjunto de cabeçalhos. Cada pacote de voz tem a carga útil, composta por um quadro (frame) de voz, muito menor que a carga útil de um pacote de dados. Desta forma, a rede IP pode tornar-se pouco eficiente para transportar sinal de voz. Além disso, o serviço de voz requer também interatividade o que implica em realocar, através de mecanismos apropriados, os recursos da rede IP. Uma das técnicas que pode ser usada é a aplicação de política de priorização do tráfego de voz que em contrapartida pode degradar o desempenho de tráfego com prioridade menor. A previsão de tráfego de voz crescente na rede IP pode torná-la bastante ineficiente, além de degradar o desempenho do tráfego de dados. Para minimizar este problema o esquema de multiplexagem dos quadros de voz pode ser usado. Um modelo matemático é proposto neste estudo para analisar o impacto do tráfego do pacote de voz em uma rede IP. O estudo é conduzido considerando-se sem e com a aplicação de multiplexagem de quadros de voz nos pacotes de voz e o parâmetro de desempenho é o atraso de cada pacote na rede IP. Em seguida, um outro modelo mais complexo, com fontes de voz ON-OFF e de dados do tipo HTTP, é simulado no ambiente do MatLab/SimEvent para o mesmo cenário estudado no modelo analítico. Os resultados obtidos mostraram que o comportamento da rede IP é similar tanto no modelo analítico como no modelo simulado e que a técnica de multiplexagem dos quadros de voz é um esquema eficiente para economizar a largura de banda de um enlace da rede IP. / Abstract: In this study, the performance and impact of voice traffic in an IP network are evaluated. In the IP network, the voice signal is transmitted through packets that are identified by a set of headers. Each voice packet has payload composed of one voice frame, which is smaller than the payload of data packet. In this way, the IP network may become ineffective to carry the voice signal. Furthermore, the voice service also requires interactivity which means the need for reallocation, through appropriate mechanisms, the resources of the IP network. One of the techniques may be used is through the adoption of voice traffic priority policy which on other hand it may degrade the performance of data traffic with lower priority. The expected fast growing of voice traffic in IP network can make it inefficient as well as to degrade the data traffic performance. To minimize this problem the voice stream multiplexing scheme can be used. A mathematical model is proposed in this study to examine the impact of voice packet traffic in an IP network. The study is carried out considering with and without the application of voice frame multiplexing and the performance parameter is the delay of each packet in the IP network. Then, a more complex model, with ONOFF voice sources and data sources of HTTP type, is simulated in MatLab/SimEvent environment for the same scenario used in analytical model. The obtained results showed that the IP network behavior is similar in both analytical and simulated models and that voice frame multiplexing technique is an efficient scheme to save the bandwidth of a link. / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

Made available in DSpace on 2016-03-15T19:37:40Z (GMT). No. of bitstreams: 1 Palmerston Donizzeti Taveira.pdf: 3709250 bytes, checksum: f7776004371e059d73f0d20c8d735c07 (MD5) Previous issue date: 2006-08-02 / The optical amplifier has improved the optical communication systems because they lead to an increase in transmission capacity of medium and long haul optical systems, with technological advantages over electronic regenerators. The optical amplifier are relatively simple to deploy and can be used in optical links without any troubles regarding signal transmission rate improvement and signal modulation changes, as a consequence of these issues they can substitute the electronic regenerator enhancing security with low operation cost. The CWDM systems multiplex optical wavelength with a low cost in metropolitan networks. It was developed to connect backbone networks to metro core and edge networks with cost saving over DWDM systems but lower transmission capacity. We have developed and characterized in our research a discrete Raman amplifier for operation in O band. We connected the amplifier in a point to point CWDM in order to analyze the gain on the system transmission capacity and the impairments that appears in the system. Working with a eight channel CWDM in O band, modulated with 2.5 Gbit/s, we have demonstrated that we can use a discrete Raman amplifier in single configurations, pre amplifier, booster and line amplifier and shared configuration with booster and pre amplifier to increase the transmission capacity that means, increase the length of the optical link. We have increased in 110% the length of the optical link with a shared configuration of two amplifiers with 10 dB gain for each one. / Os amplificadores ópticos revolucionaram a tecnológica das comunicações ópticas, pois possibilitaram o aumento da capacidade de transmissão dos sistemas ópticos de média e longa distância, com vantagens tecnológicas sobre os regeneradores. Estes dispositivos são relativamente simples de serem desenvolvidos, utilizam poucos componentes e podem ser utilizados nas redes ópticas de forma transparente a taxa de transmissão e modulação do sinal. Substituem assim, com vantagens, os regeneradores eletrônicos, agregando segurança e baixo custo à operação das redes ópticas. Os sistemas CWDM realizam a multiplexação óptica de comprimentos de onda a um baixo custo em redes metropolitanas. São utilizados para conectar as redes de transporte de alta capacidade às redes de acesso, trazendo uma larga vantagem em custo sobre os sistemas DWDM, porém com menor capacidade de transmissão. Nosso trabalho de pesquisa consistiu em desenvolver e caracterizar um amplificador Raman discreto na banda O (1260 a 1360 nm), aplicando este amplificador em um sistema CWDM ponto a ponto com taxa de transmissão de 2.5 Gbit/s por canal e analisando o aumento na capacidade de transmissão e os efeitos que degradam o sinal transmitido. Trabalhando com um sistema CWDM com oito canais na banda O, demonstramos que podemos utilizar um amplificador Raman discreto nas configurações isoladas de pré-amplificador, booster e amplificador de linha e na configuração simultânea de booster e pré-amplificador para aumentar a capacidade de transmissão. Aumentamos o comprimento original do enlace em 110%.

Le trafic internet mondial étant toujours plus important, l’augmentation du débit transmis dans les fibres optiques de façon à diminuer le coût par bit est nécessaire. Les technologies actuelles sur fibres monomodes approchent une limite fondamentale empêchant une augmentation conséquente du débit dans les fibres optiques. Une nouvelle technique appelée le multiplexage de mode spatial est une solution pour dépasser cette limite. Plusieurs modes spatiaux, correspondant aux solutions des équations de propagation, sont multiplexés dans une fibre spécifique pour multiplier le débit transmis par le nombre de modes utilisés. Pour la mise en œuvre de cette technique, ma stratégie est de séparer les modes spatiaux de façon hybride, c'est-à-dire d’abord optiquement puis avec un traitement numérique relativement peu complexe. Dans cette approche, la diaphonie entre les modes non dégénérés n’est pas compensée et doit donc être minimisée sur toute la ligne de transmission pour une transmission de données de bonne qualité. Par l’utilisation d’un multiplexeur-démultiplexeur et d’une fibre pouvant propager six modes spatiaux et induisant peu de diaphonie, j’ai réalisé la transmission d’un signal monocanal de 6x100 Gbit/s dans une fibre de 40 km. Pour des transmissions plus longues que 80 km, un amplificateur est nécessaire pour compenser les pertes de la fibre optique. J’ai donc conçu un amplificateur à fibre dopé Erbium pour cinq modes spatiaux induisant peu de diaphonie et avec un gain supérieur à 15 dB pour tous les modes et réalisé la transmission d’un signal de 5x100 Gbit/s sur une distance de 80 km avec un traitement numérique relativement simple. / With the growth of the internet traffic, it is necessary to increase the throughput of optical fibers in such a manner that the cost per transmitted bit decreases. With the current single mode fiber technologies, we are approaching a fundamental limit which prevents us to continue to increase the throughput in these fibers. A new technique called spatial mode multiplexing is investigated as a solution to overcome this limit. Several spatial modes, corresponding to the solutions of the propagation equations in the fiber, are multiplexed into a specific fiber in order to multiply the throughput by the number of transmitted modes. To implement this technique, my strategy is to separate modes first optically and to use a relatively low complex digital signal processing (DSP). Thus the crosstalk between spatial modes should be minimized in the whole transmission line to retrieve the data. By using a multiplexer-demultiplexer and a fiber supporting six modes and inducing low crosstalk, I achieved 40 km long transmission of six modes each transporting 100 Gb/s on a single wavelength. Transmissions longer than 80 km need an amplifier supporting all modes to compensate the losses in the optical fiber. I thus built a five modes Erbium doped fiber amplifier with low crosstalk and >15 dB gain to achieve the transmission of five modes carrying each 100 Gbit/s in an 80 km long fiber with low complex DSP.