This thesis addresses the problem of detection of an unknown binary event. In particular, we consider centralized detection, distributed detection, and network security in wireless sensor networks (WSNs). The communication links among SNs are subject to limited SN transmit power, limited bandwidth (BW), and are modeled as orthogonal channels with path loss, flat fading and additive white Gaussian noise (AWGN). We propose algorithms for resource allocations, fusion rules, and network security. In the first part of this thesis, we consider the centralized detection and calculate the optimal transmit power allocation and the optimal number of quantization bits for each SN. The resource allocation is performed at the fusion center (FC) and it is referred as a 'centralized' approach. We also propose a novel fully 'distributed' algorithm to address this resource allocation problem. What makes this scheme attractive is that the SNs share with their neighbors just their individual transmit power at the current states. Finally, the optimal soft fusion rule at the FC is derived. But as this rule requires a-priori knowledge that is difficult to attain in practice, suboptimal fusion rules are proposed that are realizable in practice. The second part considers a fully distributed detection framework and we propose a two-step distributed quantized fusion rule algorithm where in the first step the SNs collaborate with their neighbors through error-free, orthogonal channels. In the second step, local 1-bit decisions generated in the first step are shared among neighbors to yield a consensus. A binary hypothesis testing is performed at any arbitrary SN to optimally declare the global decision. Simulations show that our proposed quantized two-step distributed detection algorithm approaches the performance of the unquantized centralized (with a FC) detector and its power consumption is shown to be 50% less than the existing (unquantized) conventional algorithm. Finally, we analyze the detection performance of under-attack WSNs and derive attacking and defense strategies from both the Attacker and the FC perspective. We re-cast the problem as a minimax game between the FC and Attacker and show that the Nash Equilibrium (NE) exists. We also propose a new non-complex and efficient reputation-based scheme to identify these compromised SNs. Based on this reputation metric, we propose a novel FC weight computation strategy ensuring that the weights for the identified compromised SNs are likely to be decreased. In this way, the FC decides how much a SN should contribute to its final decision. We show that this strategy outperforms the existing schemes.

Ultra-wideband (UWB) communication has been the subject of extensive research in recent years due to its unique capabilities and potential applications, particularly in short-range multiple access wireless communications. However, many important aspects of UWB-based communication systems have not yet been thoroughly investigated. The propagation of UWB signals inside very small enclosed environments is one of the important issues with significant impacts on the future direction, scope, and generally the extent of the success of UWB technology. The objective of this thesis is to obtain a more thorough and comprehensive understanding of ultra-small UWB channels for communication applications and design issues for enhancing the data rate of UWB systems. This works supports the postulation of a high capacity UWB wireless interconnect scheme for communicating devices within conducting enclosures – a wireless “backplane”. This thesis proposes the use of an Ultra-Wide Bandwidth (UWB) ultra-small scale wireless interconnect scheme for use within electrically small enclosures. Such ultra-small environments (size ≤ 10 wavelengths) are topologically much more complex, being more cluttered, than typical indoor environments (size ≥ 10 wavelengths). The concept is presented through two different scenarios. Firstly, a PC Tower case is presented as a model environment and the work seeks to present the optimum channel performance, where EMI issues are discussed and problem avoidance proposed. Secondly, in order to extrapolate the different results from the study inside the PC, an investigation is carried out using an Aluminium tower case as a more generic model environment. The analysis is based on the behaviour of box modes within a conducting resonator enclosure and the effective communications bandwidth for UWB systems for different sizes and components within. From these general considerations the research presents theoretical and experimental results from which are derived the communications metrics measured within enclosures. Simulations of the different scenarios are performed using different techniques such as ray tracing and a full wave model, based on CST Microstripes. Empirical data is recorded using a vector network analyser (VNA)-based wideband channel sounding system where channel measurements are carried out in every scenario regarding different aspects such as frequency response and time domain analysis, evaluation of the channel capacity, power delay study and the nature of the environment.

This collection of published scholarly work concerns the growth and development of community radio and mobile telephony during the period 2000-2009, with reference to specific examples and case studies. The associated report examines the extent that the public are using these media to the benefit of individuals and communities and also suggests that the public have regained use of the electromagnetic spectrum through the use of community radio and mobile phones. The over arching hypothesis is that both community radio and mobile telephony are: • providing benefits to society, rangmg from improving daily life and avoiding inconveniences, to ameliorating critical or life-threatening situations and resisting oppression, • re-establishing rights of usage in the electromagnetic spectrum for ordinary members of the public which were surrendered to governmental authorities in the early years of spectrum experimentation, • using the electromagnetic spectrum as a tool for activism, political discussion, social engagement and exchange of information about matters of common interest, • worthy of research and examination to investigate how these two forms of communications media are impacting on the lives of individuals and society as a whole.

yes / This is the twelfth workshop to be organised under the postgraduate programmes in electrical and electronic engineering (EEE). In total, thirty-four papers from forty-nine submissions have been selected for the Proceedings. The Proceedings comprises eleven themes, which reflect today's research agenda.

This is the thirteenth workshop to be organised under the postgraduate programmes in electrical and electronic engineering (EEE). In total, twenty-nine papers, divided into eight themes, comprise the Proceedings.

Es desenvolupa una metodologia que combina algoritmes exploratoris i iteratius que pren com a base el concepte de concordança del coeficient de correlació W de Kendall. A partir de conjunts complexos d'ítems i les seves puntuacions (activitats d'avaluació, problemes, pràctiques, indicadors de rendiment, mesuraments i, en general, qualsevol variable quantitativa) s'aconsegueixen identificar conjunts concordants, és a dir, estructures explicatives de la dificultat del conjunt de ítems. La lectura d'aquests conjunts es pot fer de dues maneres gràcies a la informació que proporcionen els algoritmes creats: a) Transversal, de manera que els conjunts concordants formen el "esquelet de dificultat" del problema i són, per tant, referències per estudiar la resta de puntuacions en altres ítems. b) Longitudinal, mitjançant l'estudi del que anomenem Mapes de Concordança, els quals mostren l'evolució dels conjunts concordants en anar incorporant elements en cada iteració, i detectant per tant els ítems discordants respecte a conjunts estables donats. L'aplicació d'aquesta metodologia és molt àmplia, i és susceptible de ser posada en pràctica en qualsevol camp de les ciències on es realitzin mesures i es vulgui observar les variacions creuades entre individus. En aquesta investigació s'aplica a l'assignatura de Laboratori de mesures electròniques. Els resultats aporten llum a la manera de millorar les pràctiques existents i de construir-ne de noves en el futur. / Se desarrolla una metodología que combina algoritmos exploratorios e iterativos que toma como base el concepto de concordancia del coeficiente de correlación W de Kendall. A partir de conjuntos complejos de ítems y sus puntuaciones (actividades de evaluación, problemas, prácticas, indicadores de rendimiento, mediciones y, en general, cualquier variable cuantitativa) se consiguen identificar conjuntos concordantes, es decir, estructuras explicativas de la dificultad del conjunto de ítems. La lectura de estos conjuntos puede hacerse de dos maneras gracias a la información que proporcionan los algoritmos creados: a) Transversal, de manera que los conjuntos concordantes forman el “esqueleto de dificultad” del problema y son, por tanto, referencias para estudiar el resto de puntuaciones en otros ítems. b) Longitudinal, mediante el estudio de lo que denominamos Mapas de Concordancia, los cuales muestran la evolución de los conjuntos concordantes al ir incorporando ítems en cada iteración, y detectando por tanto los ítems discordantes respecto a conjuntos estables dados. La aplicación de dicha metodología es muy amplia, siendo susceptible de ser puesta en práctica en cualquier campo de las ciencias donde se realicen mediciones y se quiera observar las variaciones cruzadas entre individuos. En la presente investigación se aplica a la asignatura de Laboratorio de medidas electrónicas. Los resultados arrojan luz sobre la manera de mejorar las prácticas existentes y de construir otras nuevas en el futuro. / We have developed a new methodology that combines both exploratory and iterative algorithms which is based on the concept of concordance of the correlation coefficient W of Kendall. Starting from complex sets of items and their scores (assessment activities, problems, practices, performance indicators, measurements and, in general, any quantitative variable) it is possible to identify consistent sets, i.e., structures that explain the difficulty of the set of items. Reading these sets can be done in two different ways thanks to the information provided by the algorithms created: a) Transversal, so that the concordant sets form the "backbone difficulty" of the problem and, therefore, they become references to study the remaining scores on other items. b) Longitudinal, by studying what we call concordance maps, which show the evolution of the consistent sets when new items are incorporated after each iteration and thus detecting the discordant items with regard to given stable sets. The application of this methodology is very broad, being useful in any field of science where measurements are carried out and you may want to see cross-variations among individuals. In this research it has been applied to the subject Electronic Measurements Laboratory. The results point to different ways to improve the existing practices and create new ones in the future.