Based on the Umbilical Cord system, this project enriches the Ubiquitous Computing system with a Free Roaming system. This Free Roaming consists of a distributed authentication system, a data caching system and a communication system between them. It allows user to roam within this system and access his data everywhere. Together with the Umbilical Cord system, a Ubiquitous Computing system is functionally completed as a prototype, and is ready to be deployed into the Internet.

In this world of growing technology, any small improvement in the present scenario would create a revolution. One of the popular revolutions in the computer science field is parallel computing. A single parallel execution is not sufficient to see its non-deterministic features, as same execution with the same data at different time would end up with a different path. In order to see how non deterministic a parallel execution can extend up to, creates the need of the ensemble of executions. This project implements a program to estimate the Gibbs Entropy for an ensemble of parallel executions. The goal is to develop tools for studying the non-deterministic feature of parallel code based on execution entropy and use these developed tools for current and future research.

"January 2003" Includes bibliographical references (leaves 120-129) Presents performance analyses of dynamic, stochastic task scheduling policies for a real- time-communications system where tasks lose value as they are delayed in the system.

"January 2003" / Includes bibliographical references (leaves 120-129) / x, 129 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Presents performance analyses of dynamic, stochastic task scheduling policies for a real- time-communications system where tasks lose value as they are delayed in the system. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 2003

In this work, a multilayer security solution for digital communication systems is provided by considering the joint effects of physical-layer security channel codes with application-layer cryptography. We address two problems: first, the cryptanalysis of error-prone ciphertext; second, the design of a practical physical-layer security coding scheme. To our knowledge, the cryptographic attack model of the noisy-ciphertext attack is a novel concept. The more traditional assumption that the attacker has the ciphertext is generally assumed when performing cryptanalysis. However, with the ever-increasing amount of viable research in physical-layer security, it now becomes essential to perform the analysis when ciphertext is unreliable. We do so for the simple substitution cipher using an information-theoretic framework, and for stream ciphers by characterizing the success or failure of fast-correlation attacks when the ciphertext contains errors. We then present a practical coding scheme that can be used in conjunction with cryptography to ensure positive error rates in an eavesdropper's observed ciphertext, while guaranteeing error-free communications for legitimate receivers. Our codes are called stopping set codes, and provide a blanket of security that covers nearly all possible system configurations and channel parameters. The codes require a public authenticated feedback channel. The solutions to these two problems indicate the inherent strengthening of security that can be obtained by confusing an attacker about the ciphertext, and then give a practical method for providing the confusion. The aggregate result is a multilayer security solution for transmitting secret data that showcases security enhancements over standalone cryptography.

In immersive audio environments with distributed microphones, Independent Component Analysis (ICA) can be applied to uncover signals from a mixture of other signals and noise, such as in a cocktail party recording. ICA algorithms have been developed for instantaneous source mixtures and convolutional source mixtures. While ICA for instantaneous mixtures works when no delays exist between the signals in each mixture, distributed microphone recordings typically result various delays of the signals over the recorded channels. The convolutive ICA algorithm should account for delays; however, it requires many parameters to be set and often has stability issues. This thesis introduces the Channel Aligned FastICA (CAICA), which requires knowledge of the source distance to each microphone, but does not require knowledge of noise sources. Furthermore, the CAICA is combined with Time Frequency Masking (TFM), yielding even better SOI extraction even in low SNR environments. Simulations were conducted for ranking experiments tested the performance of three algorithms: Weighted Beamforming (WB), CAICA, CAICA with TFM. The Closest Microphone (CM) recording is used as a reference for all three. Statistical analyses on the results demonstrated superior performance for the CAICA with TFM. The algorithms were applied to experimental recordings to support the conclusions of the simulations. These techniques can be deployed in mobile platforms, used in surveillance for capturing human speech and potentially adapted to biomedical fields.

Thesis (Engineer's) --Naval Postgraduate School, 1976. / "September 1976." "AD A035848." Includes bibliographical references (leaves 122-123) Available via the Internet.

Traditionally, connection management applications (referred to as patchbays) for high-speed audio networking, are predominantly developed using third-generation languages such as C, C# and C++. Due to the rapid increase in distributed audio/video network usage in the world today, connection management applications that control signal routing over these networks have also evolved in complexity to accommodate more functionality. As the result, high-speed audio networking application developers require a tool that will enable them to develop complex connection management applications easily and within the shortest possible time. In addition, this tool should provide them with the reliability and flexibility required to develop applications controlling signal routing in networks carrying real-time data. High-speed audio networks are used for various purposes that include audio/video production and broadcasting. This investigation evaluates the possibility of using Adobe Flash Professional 8, using ActionScript 2.0, for developing connection management applications. Three patchbays, namely the Broadcast patchbay, the Project studio patchbay, and the Hospitality/Convention Centre patchbay were developed and tested for connection management in three sound installation networks, namely the Broadcast network, the Project studio network, and the Hospitality/Convention Centre network. Findings indicate that complex connection management applications can effectively be implemented using the Adobe Flash IDE and ActionScript 2.0.

Orientador: Yuzo Iano / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-05T13:46:30Z (GMT). No. of bitstreams: 1 Silva_FernandoSilvestreda_D.pdf: 35017484 bytes, checksum: fb460a6a42e44fe0a50e94599ac027fc (MD5) Previous issue date: 2005 / Resumo: A excelente qualidade visual e taxa de compressão dos codificadores fractais de imagem tem aplicações limitadas devido ao exaustivo tempo de codificação inerente. Esta pesquisa apresenta um novo codificador híbrido de imagens que aplica a velocidade da transformada wavelet à qualidade da compressão fractal. Neste esquema, uma codificação fractal acelerada usando a classificação de domínios de Fisher é aplicada na sub-banda passa-baixas de uma imagem transformada por wavelet e uma versão modificada do SPIHT (Set Partitioned in Hierarchical Trees) é aplicada nos coeficientes remanescentes. Os detalhes de imagem e as características de transmissão progressiva da transformada wavelet são mantidas; nenhum efeito de bloco comuns às técnicas fractais é introduzido, e o problema de fidelidade de codificação comuns aos codificadores híbridos fractal-wavelet é resolvido. O sistema proposto reduz o tempo médio de processamento das imagens em 94% comparado com o codificador fractal tradicional e um ganho de 0 a 2,4dB em PSNR sobre o algoritmo SPIHT puro. Em ambos os casos, o novo esquema proposto apresentou melhorias em temos de qualidade subjetiva das imagens para altas, médias e baixas taxas de compressão / Abstract: The excellent visual quality and compression rate of fractal image coding have limited applications due to exhaustive inherent encoding time. This research presents a new fast and efficient image coder that applies the speed of the wavelet transform to the image quality of the fractal compression. In this scheme, a fast fractal encoding using Fisher¿s domain classification is applied to the lowpass subband of wavelet transformed image and a modified SPIHT coding (Set Partitioning in Hierarchical Trees), on the remaining coefficients. The image details and wavelet progressive transmission characteristics are maintained; no blocking effects from fractal techniques are introduced; and the encoding fidelity problem common in fractal-wavelet hybrid coders is solved. The proposed scheme provides an average of 94% reduction in encoding-decoding time compared to the pure accelerated Fractal coding results, and a 0-2,4dB gain in PSNR over the pure SPIHT coding. In both cases, the new scheme improves the subjective quality of pictures for high, medium and low bit rates / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

Esta pesquisa tem por objetivo fundamental investigar, descrever e analisar o impacto das tecnologias digitais sobre as formas de ação nas artes cênicas contemporâneas. Entendemos que as tecnologias digitais contribuem para alterar a ação linear e frontal precipitada a partir de um ator humano, típica das formas artísticas tradicionais, dando origem a processos nos quais elementos humanos e não humanos interagem numa configuração ecossistêmica e em rede. Partindo de um percurso histórico-teórico que busca refletir sobre a presença e a participação da tecnologia nas artes cênicas, do teatro grego a nossa contemporaneidade, apresentamos a perspectiva da ação em rede, pela qual se pretende analisar a cena contemporânea como uma ecologia e pensar as novas formas em que se organizam as relações entre artista, espectador e obra de arte no contexto das tecnologias digitais. Como analisar, por exemplo, uma obra em que atores, em lugares físicos distintos, contracenam apenas a partir de uma conexão de Internet? Qual a natureza da relação com o espaço característico dessas obras, sobretudo quando comparadas àquelas que se ancoram na pressuposição de um espaço físico? Em última instância, promovendo a pesquisa transdisciplinar, pretende-se, assim, analisar como a comunicação digital estaria alterando a própria forma de atuação artística em nossa época. Para aprofundar a reflexão, a pesquisa apresenta uma análise de casos representativos, com obras do grupo catalão-espanhol La Fura dels Baus, do francês Collectif Iduun e do brasileiro Coletivo Phila 7, a fim de realizar uma articulação teórico-prática entre seus trabalhos e alguns dos conceitos que tangenciamos, como presença, tempo, espaço e performatividade da tecnologia / This research aims to investigate, describe and analyze the impact of digital technologies on the forms of action in contemporary performing arts. We believe that digital technologies contribute to change the linear and frontal action, precipited from a human actor and characteristic of traditional art forms, giving rise to processes in which human and non-human elements interact in an ecosystemic and networked configuration. From a historical and theoretical path that seeks to reflect on the presence and the participation of the technology in the performing arts - from the Greek theater to our times -, we present the perspective of the networked action, by which we intend to analyze the contemporary scene as an ecology and to think the new ways in which the relations between artist, spectator and work of art are organized in the context of the digital technologies. How to analyze, for instance, a work in which actors, in different physical locations, perform only by an Internet connection? What is the nature of the relationship with the space in this works, especially when compared to those anchored in a physical space? Finally, we intend, therefore, to analyze how the digital communications are altering the forms of art in our time. To develop our reflection, the research presents an analysis of representative cases, with works of Catalan-Spanish group La Fura dels Baus, the French Collectif Iduun and the Brazilian Coletivo Phila 7, in order to realize a theoretical and practical connection between their works and some of the concepts which we discuss, as presence, time, space and performativity of the technology.