Soft information based protocols in network coded relay networks

Future wireless networks aim at providing higher quality of service (QoS) to mobile users. The emergence of relay technologies has shed light on new methodologies through which the system capacity can be dramatically increased with low deployment cost. In this thesis, novel relay technologies have been proposed in two practical scenarios: wireless sensor networks (WSN) and cellular networks. In practical WSN designs, energy conservation is the single most important requirement. This thesis draws attention to a multiple access relay channels model in the WSN. The network coded symbol for the received signals from correlated sources has been derived; the network coded symbol vector is then converted into a sparse vector, after which a compressive sensing (CS) technique is applied over the sparse signals. A theoretical proof analysis is derived regarding the reliability of the network coded symbol formed in the proposed protocol. The proposed protocol results in a better bit error rate (BER) performance in comparison to the direct implementation of CS on the EF protocol. Simulation results validate our analyses. Another hot topic is the application of relay technologies to the cellular networks. In this thesis, a practical two-way transmission scheme is proposed based on the EF protocol and the network coding technique. A trellis coded quantization/modulation (TCQ/M) scheme is used in the network coding process. The soft network coded symbols are quantized into only one bit thus requiring the same transmission bandwidth as the simplest decode-and-forward protocol. The probability density function of the network coded symbol is derived to help to form the quantization codebook for the TCQ. Simulations show that the proposed soft forwarding protocol can achieve full diversity with only a transmission rate of 1, and its BER performance is equivalent to that of an unquantized EF protocol

The phenomenology of negative and positive imagery in early psychosis

This thesis is presented in three parts and focuses on intrusive cognitions in psychopathology, particularly the phenomenology of mental imagery in early psychosis. Part one is a systematic review which examines the impact of suppression, rumination and worry, hypothesised maintenance factors in cognitive models of PTSD, on trauma-related intrusions. The reviewed experimental studies provide support for increased intrusion frequency following suppression in clinical samples only with limited evidence of an adverse impact on affect. There was evidence of decreased mood following rumination in analogue studies. A number of methodological issues are discussed which warrant consideration in trauma-related experimental research. Part two is an empirical paper that investigates negative and positive mental imagery in early psychosis. Thirty-one service users from Early Intervention in Psychosis services participated in this study. The phenomenological characteristics, thematic content and appraisals of imagery in addition to participant’s ability to intentionally generate positive future-oriented images were investigated in this mixed-methods study. Negative imagery content reflected external threat, traumatic experiences and also depressive and anxious concerns. Positive imagery depicted affiliation and the achievement of personal goals. Idiosyncratic appraisals of imagery varied in terms of their perceived dangerousness, benefit and source. Furthermore, depression and social anxiety were associated with the vividness and perceived likelihood of intentionally generated, positive future-oriented images. Part three is a critical appraisal of the investigation presented in the empirical paper. It discusses challenges in the examination of cognitive and behavioural responses to intrusive imagery, an issue highlighted in the literature review. It concludes by considering the role of positive imagery in therapeutic interventions for individuals with psychosis

Visualising lighting simulations for automotive design evaluations using emerging technologies

Automotive design visualisation is at a turning point with the commercial development of immersive technologies such as virtual reality, among other displays and visual interfaces. A fundamental objective of this research is to assess how seamlessly the integration of emerging visualisation technologies can be implemented into the new product development methodologies, with the use of lighting simulation, design review applications and the use of immersive hardware and software. Optical automotive considerations such as display legibility, veiling glare, and perceived quality among other current processes of Systemic Optical Failure (SOF) modes are analysed, to determine how the application of new immersive visualisation technologies could improve the efficiency of new product development, in particular reducing time and cost in early stages while improving decision making and quality. Different hardware and software combinations were investigated in terms of their ability to realistically represent design intent. Following on from this investigation, a user study was carried out with subjects from various automotive engineering disciplines, to evaluate a range of potential solutions. Recommendations are then made as to how these solutions could be deployed within the automotive new product development process to deliver maximum value

The JPEG2000 still image compression standard

The development of standards (emerging and established) by the International Organization for Standardization (ISO), the International Telecommunications Union (ITU), and the International Electrotechnical Commission (IEC) for audio, image, and video, for both transmission and storage, has led to worldwide activity in developing hardware and software systems and products applicable to a number of diverse disciplines [7], [22], [23], [55], [56], [73]. Although the standards implicitly address the basic encoding operations, there is freedom and flexibility in the actual design and development of devices. This is because only the syntax and semantics of the bit stream for decoding are specified by standards, their main objective being the compatibility and interoperability among the systems (hardware/software) manufactured by different companies. There is, thus, much room for innovation and ingenuity. Since the mid 1980s, members from both the ITU and the ISO have been working together to establish a joint international standard for the compression of grayscale and color still images. This effort has been known as JPEG, the Join