Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 132-143).

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006. / Buck, John, Committee Co-Chair ; Ferguson, Ian, Committee Chair ; Krishnamurthy,Vikram, Committee Member ; Chang, Gee-Kung, Committee Member ; Callen, W. Russell Jr., Committee Member ; Summers, Christopher, Committee Member.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 139-144).

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 149-154).

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2008. / M.Phil. in Electronic Technology. Includes bibliographical references (p. 57-58).

abstract: Demands in file size and transfer rates for consumer-orientated products have escalated in recent times. This is primarily due to the emergence of high definition video content. Now factor in the consumer desire for convenience, and we find that wireless service is the most desired approach for inter-connectivity. Consumers expect wireless service to emulate wired service with little to virtually no difference in quality of service (QoS). The background section of this document examines the QoS requirements for wireless connectivity of high definition video applications. I then proceed to look at proposed solutions at the physical (PHY) and the media access control (MAC) layers as well as cross-layer schemes. These schemes are subsequently are evaluated in terms of usefulness in a multi-gigabit, 60 GHz wireless multimedia system targeting the average consumer. It is determined that a substantial gap in published literature exists pertinent to this application. Specifically, little or no work has been found that shows how an adaptive PHYMAC cross-layer solution that provides real-time compensation for varying channel conditions might be actually implemented. Further, no work has been found that shows results of such a model. This research proposes, develops and implements in Matlab code an alternate cross-layer solution that will provide acceptable QoS service for multimedia applications. Simulations using actual high definition video sequences are used to test the proposed solution. Results based on the average PSNR metric show that a quasi-adaptive algorithm provides greater than 7 dB of improvement over a non-adaptive approach while a fully-adaptive alogrithm provides over18 dB of improvement. The fully adaptive implementation has been conclusively shown to be superior to non-adaptive techniques and sufficiently superior to even quasi-adaptive algorithms. / Dissertation/Thesis / M.S. Engineering 2011

Photonic quantum information processing has emerged as a powerful platform for realising quantum-enhanced technologies. In order to be scalable, many of these technologies depend on the availability of a suitable quantum memory for the coherent storage and on-demand retrieval of photonic quantum states. In this thesis, I investigate broadband light storage in a room-temperature Raman memory, implemented both in free space and, for the first time, inside a low-finesse optical cavity designed for low-noise operation. The ability of the Raman memory to preserve phase coherence was tested by storing coherent polarisation states in two spatially separate atomic ensembles. Polarisation storage with a fidelity of up to 97 ± 1% was demonstrated by performing full process tomography on the system. The Raman memory was then interfaced for the first time with a spontaneous parametric downconversion (SPDC) source of heralded, GHz-bandwidth single photons. The memory performance was characterised by measuring the second-order autocorrelation of the retrieved fields. While the SPDC input photon statistics showed a clear influence on the statistics of the retrieved field, four-wave mixing (FWM) noise, stimulated by spontaneous Raman scattering, prevented the preservation of non-classical photon statistics during read-out. Suppressing this source of noise represents the last remaining challenge for realising a broadband single-photon Raman memory suitable for quantum information applications. To this end, I demonstrate a novel cavity implementation of the Raman memory which reduces the FWM contribution relative to the signal field by re-distributing the density of states into which the noise photons can be scattered. Cavity-enhanced memory operation was investigated using weak coherent input states, showing a significant improvement of the signal-to-noise ratio compared to the free-space memory implementation. This proof-of-principle demonstration suggests that cavity Raman memories may offer a practical route towards low-noise, high-bandwidth quantum storage at room temperature.

Apresentamos e analisamos as técnicas de multiplexação TDM convencional e estatística, para concentração remota de dados. Como exemplo estudamos o problema da Rede Transdata, em função da taxa de utilização dos terminais (p) e do fator de compressão dos códigos (d). As principais conclusões são: - A técnica TDM convencional proporciona uma economia da ordem de 50% em canais de voz, sem introduzir atrasos. - A técnica TDM estatística proporciona uma economia da ordem de 70% em canais de voz, introduzindo cerca de 80 ms de atraso, por terminal. Em vista do exposto, os fabricantes, os usuários e as concessionárias de telecomunicações devem procurar realizar um trabalho integrado, no sentido de viabilizar a utilização de tais técnicas. / The conventional and statistical TDM techniques are presented and analysed for remote data concentration. The Transdata network problem was analysed according to terminal utilization factors (p) and code compression factors (d). As main conclusions, we have: - TDM conventional multiplexers can give a 50% voice channel economy without delay. - TDM statistical multiplexers can give a 70% voice channel economy with 80 ms delay per terminal. Due to these factors, the producer, user and telecommunications operating company should try to implement an integrated programme in order to make possible the utilization of such techniques.