Global illumination techniques are used to improve the realism of 3D scenes. Calculating accurate global illumination requires a method for solving the rendering equation. However, the integral form of this equation cannot be evaluated. This thesis presents research in non real-time illumination techniques which are evaluated with a finite number of light rays. This includes a new technique which improves realism of the scene over traditional techniques. All computer rendering requires distortion free texture mapping to appear plausible to the eye. Inverse texture mapping, however, can be numerically unstable and computationally expensive. Alternative techniques for texture mapping and texture coordinate generation were developed to simplify rendering. Real-time rendering is improved by pre-calculating non real-time reflections. The results of this research demonstrate that a polynomial approximation of reflected light can be more accurate than a constant approximation. The solution improves realism and makes use of new features in graphics hardware.

Turtle mobile robot which is able to interact intelligently with a dynamically changing environment.

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This thesis presents a link-level latency analysis for real-time network-on-chip interconnects that use priority-based wormhole switching. This analysis incorporates both direct and indirect interferences from other traffic flows, and it leverages pipelining and parallel transmission of data across the links. The resulting link-level analysis provides a tighter worst-case upper-bound than existing techniques, which we verify with our analysis and simulation experiments. Our experiments show that on average, link-level analysis reduces the worst-case latency by 28.8%, and improves the number of flows that are schedulable by 13.2% when compared to previous work.

Global illumination techniques are used to improve the realism of 3D scenes. Calculating accurate global illumination requires a method for solving the rendering equation. However, the integral form of this equation cannot be evaluated. This thesis presents research in non real-time illumination techniques which are evaluated with a finite number of light rays. This includes a new technique which improves realism of the scene over traditional techniques. All computer rendering requires distortion free texture mapping to appear plausible to the eye. Inverse texture mapping, however, can be numerically unstable and computationally expensive. Alternative techniques for texture mapping and texture coordinate generation were developed to simplify rendering. Real-time rendering is improved by pre-calculating non real-time reflections. The results of this research demonstrate that a polynomial approximation of reflected light can be more accurate than a constant approximation. The solution improves realism and makes use of new features in graphics hardware.

This thesis explores how granular synthesis can be used in live performances. The early explorations of granular synthesis are first investigated, leading up to modern trends of electronic performance involving granular synthesis. Using this background it sets about to create a granular synthesis instrument that can be used for live performances in a range of different settings, from a computer quartet, to a flute duet. The instrument, an electronic fish called the poseidon, is documented from the creation and preparation stages right through to performance.

Doctor of Philosophy (PhD) / Real-time control systems are widely deployed in many applications. Theory and practice for the design and deployment of real-time control systems have evolved significantly. From the design perspective, control strategy development has been the focus of the research in the control community. In order to develop good control strategies, process modelling and analysis have been investigated for decades, and stability analysis and model-based control have been heavily studied in the literature. From the implementation perspective, real-time control systems require timeliness and predictable timing behaviour in addition to logical correctness, and a real-time control system may behave very differently with different software implementations of the control strategies on a digital controller, which typically has limited computing resources. Most current research activities on software implementations concentrate on various scheduling methodologies to ensure the schedulability of multiple control tasks in constrained environments. Recently, more and more real-time control systems are implemented over data networks, leading to increasing interest worldwide in the design and implementation of networked control systems (NCS). Major research activities in NCS include control-oriented and scheduling-oriented investigations. In spite of significant progress in the research and development of real-time control systems, major difficulties exist in the state of the art. A key issue is the lack of integrated design for control development and its software implementation. For control design, the model-based control technique, the current focus of control research, does not work when a good process model is not available or is too complicated for control design. For control implementation on digital controllers running multiple tasks, the system schedulability is essential but is not enough; the ultimate objective of satisfactory quality-of-control (QoC) performance has not been addressed directly. For networked control, the majority of the control-oriented investigations are based on two unrealistic assumptions about the network induced delay. The scheduling-oriented research focuses on schedulability and does not directly link to the overall QoC of the system. General solutions with direct QoC consideration from the network perspective to the challenging problems of network delay and packet dropout in NCS have not been found in the literature. This thesis addresses the design and implementation of real-time control systems with regard to dynamics analysis and integrated design. Three related areas have been investigated, namely control development for controllers, control implementation and scheduling on controllers, and real-time control in networked environments. Seven research problems are identified from these areas for investigation in this thesis, and accordingly seven major contributions have been claimed. Timing behaviour, quality of control, and integrated design for real-time control systems are highlighted throughout this thesis. In control design, a model-free control technique, pattern predictive control, is developed for complex reactive distillation processes. Alleviating the requirement of accurate process models, the developed control technique integrates pattern recognition, fuzzy logic, non-linear transformation, and predictive control into a unified framework to solve complex problems. Characterising the QoC indirectly with control latency and jitter, scheduling strategies for multiple control tasks are proposed to minimise the latency and/or jitter. Also, a hierarchical, QoC driven, and event-triggering feedback scheduling architecture is developed with plug-ins of either the earliest-deadline-first or fixed priority scheduling. Linking to the QoC directly, the architecture minimises the use of computing resources without sacrifice of the system QoC. It considers the control requirements, but does not rely on the control design. For real-time NCS, the dynamics of the network delay are analysed first, and the nonuniform distribution and multi-fractal nature of the delay are revealed. These results do not support two fundamental assumptions used in existing NCS literature. Then, considering the control requirements, solutions are provided to the challenging NCS problems from the network perspective. To compensate for the network delay, a real-time queuing protocol is developed to smooth out the time-varying delay and thus to achieve more predictable behaviour of packet transmissions. For control packet dropout, simple yet effective compensators are proposed. Finally, combining the queuing protocol, the packet loss compensation, the configuration of the worst-case communication delay, and the control design, an integrated design framework is developed for real-time NCS. With this framework, the network delay is limited to within a single control period, leading to simplified system analysis and improved QoC.

The age structure of populations is an important and often unresolved factor in ecology and wildlife management. Parameters like onset of reproduction and senescence, reproductive success and survival rate are tightly correlated with age. Unfortunately, age information of wild animals is not easy to obtain, especially for birds, where few anatomical markers of age exist. Longitudinal age data from birds banded as chicks are rare, particularly in long lived species. Age estimation in such species would be extremely useful as their long life span typically indicates slow population growth and potentially the need for protection and conservation. Telomere length change has been suggested as a universal marker for ageing vertebrates and potentially other animals. This method, termed molecular ageing, is based on a shortening of telomeres with each cell division. In birds, the telomere length of erythrocytes has been reported to decline with age, as the founder cells (haematopoietic stem cells) divide to renew circulating red blood cells. I measured telomere length in kakapo, the world largest parrot and four other bird species (Buller’s albatross, kea, New Zealand robin and saddleback) using telomere restriction fragment analysis (TRF) to assess the potential for molecular ageing in these species. After providing an overview of methods to measure telomere length, I describe how one of them (TRF) measures telomere length by quantifying the size distribution of terminal restriction fragments using southern blot of in-gel hybridization (Chapter 2). Although TRF is currently the ‘gold standard’ to measure telomere length, it suffers from various technical problems that can compromise precision and accuracy of telomere length estimation. In addition, there are many variations of the protocol, complicating comparisons between publications. I focused on TRF analysis using a non-radioactive probe, because it does not require special precautions associated with handling and disposing of radioactive material and therefore is more suitable for ecology laboratories that typically do not have a strong molecular biology infrastructure. However, most of my findings can be applied to both, radioactive and nonradioactive TRF variants. I tested how sample storage, choice of restriction enzyme, gel Abstract II electrophoresis and choice of hybridization buffer can influence the results. Finally, I show how image analysis (e.g. background correction, gel calibration, formula to calculate telomere length and the analysis window) can not only change the magnitude of estimated telomere length, but also their correlation to each other. Based on these findings, I present and discuss an extensive list of methodological difficulties associated with TRF and present a protocol to obtain reliable and reproducible results. Using this optimized protocol, I then measured telomere length of 68 kakapo (Chapter 3). Almost half of the current kakapo population consists of birds that were captured as adults, hence only their minimum age is known (i.e. time from when they were found +5 years to reach adulthood). Although molecular ageing might not be able to predict chronological age accurately, as calibrated with minimum age of some birds, it should be able to compare relative age between birds. Recently, the oldest kakapo (Richard Henry) was found to show signs of reproductive senescence. The age (or telomere length) difference to Richard Henry could have been used to approximate the remaining reproductive time span for other birds. Unfortunately, there was no change of telomere length with age in cross sectional and longitudinal samples. Analysis of fitness data available for kakapo yielded correlations between telomere length and fledging success, but they were weak and disappeared when the most influential bird was excluded from analysis. The heavy management and small numbers of kakapo make conclusions about fitness and telomere length difficult and highly speculative. However, telomere length of mothers and their chicks were significantly correlated, a phenomena not previously observed in any bird. To test if the lack of telomere loss with age is specific to kakapo, I measured telomere length of one of its closest relatives: the kea (Chapter 4). Like kakapo, telomere length did not show any correlation with age. I then further assessed the usefulness of molecular ageing in birds using only chicks and very old birds to estimate the maximum TL range in an additional long lived (Buller’s albatross) and two shorter lived species (NZ robin and saddleback). In these Abstract III species, telomere length was on average higher in chicks than in adults. However, age matched individuals showed high variations in telomere length, such that age dependent and independent telomere length could not be distinguished. These data and published results from other bird species, coupled with the limitations of methodology I have identified (Chapter 2), indicate that molecular ageing does not work in most (if not all) birds in its current suggested form. Another way to measure telomere length is telomere Q-PCR, a real-time PCR based method. Measurement of the same kakapo samples with TRF and Q-PCR did not result in comparable results (Chapter 4). Through experimentation I found that differences in amplification efficiency between samples lead to unreliable estimation of telomere length using telomere Q-PCR. These differences were caused by inhibitors present in the samples. The problem of differential amplification efficiency in Q-PCR, while known, is largely ignored by the scientific community. Although some methods have been suggested to correct for differing efficiency, most of these introduce more error than they eliminate. I developed and applied an assay based on internal standard oligonucleotides that was able to corrected EDTA induced quantification errors of up to 70% with high precision and accuracy (Chapter 5). The method, however, failed when tested with other inhibitors commonly found in DNA samples extracted from blood (i.e. SDS, heparin, urea and FeCl3). PCR inhibition was highly selective in the probe-polymerase system I used, inhibiting amplification of genomic DNA, but not amplification of internal oligonucleotide or plasmid standards in the same reaction. Internal standards are a key feature of most diagnostic PCR assays to identify false negatives arising from amplification inhibition. The differential response to inhibition I identified greatly compromises the accuracy of these assays. Consequently, I strongly recommend that researchers using PCR assays with internal standards should verify that the target DNA and internal standard actually respond similarly to common inhibitors.

Doctor of Philosophy(PhD) / Recent advances in miniaturization and low power design have led to a flurry of activity in wireless sensor networks. Sensor networks have different constraints than traditional wired networks. A wireless sensor network is a special network with large numbers of nodes equipped with embedded processors, sensors, and radios. These nodes collaborate to accomplish a common task such as environment monitoring or asset tracking. In many applications, sensor nodes will be deployed in an ad-hoc fashion without careful planning. They must organize themselves to form a multihop, wireless communication network. In sensor network environments, much research has been conducted in areas such as power consumption, self-organisation techniques, routing between the sensors, and the communication between the sensor and the sink. On the other hand, real-time communication with the Quality of Service (QoS) concept in wireless sensor networks is still an open research field. Most protocols either ignore real time or simply attempt to process as fast as possible and hope that this speed is sufficient to meet the deadline. However, the introduction of real-time communication has created additional challenges in this area. The sensor node spends most of its life routing packets from one node to another until the packet reaches the sink; therefore, the node functions as a small router most of the time. Since sensor networks deal with time-critical applications, it is often necessary for communication to meet real time constraints. However, research that deals with providing QoS guarantees for real-time traffic in sensor networks is still in its infancy.This thesis presents a real-time communication framework to provide quality of service in sensor networks environments. The proposed framework consists of four components: First, present an analytical model for implementing Priority Queuing (PQ) in a sensor node to calculate the queuing delay. The exact packet delay for corresponding classes is calculated. Further, the analytical results are validated through an extensive simulation study. Second, report on a novel analytical model based on a limited service polling discipline. The model is based on an M/D/1 queuing system (a special class of M/G/1 queuing systems), which takes into account two different classes of traffic in a sensor node. The proposed model implements two queues in a sensor node that are served in a round robin fashion. The exact queuing delay in a sensor node for corresponding classes is calculated. Then, the analytical results are validated through an extensive simulation study. Third, exhibit a novel packet delivery mechanism, namely the Multiple Level Stateless Protocol (MLSP), as a real-time protocol for sensor networks to guarantee the traffic in wireless sensor networks. MLSP improves the packet loss rate and the handling of holes in sensor network much better than its counterpart, MMSPEED. It also introduces the k-limited polling model for the first time. In addition, the whole sending packets dropped significantly compared to MMSPEED, which it leads to decrease the consumption power. Fourth, explain a new framework for moving data from the sink to the user, at a low cost and low power, using the Universal Mobile Telecommunication System (UMTS), which is standard for the Third Generation Mobile System (3G). The integration of sensor networks with the 3G mobile network infrastructure will reduce the cost of building new infrastructures and enable the large-scale deployment of sensor networks

Doctor of Philosophy (PhD) / Real-time control systems are widely deployed in many applications. Theory and practice for the design and deployment of real-time control systems have evolved significantly. From the design perspective, control strategy development has been the focus of the research in the control community. In order to develop good control strategies, process modelling and analysis have been investigated for decades, and stability analysis and model-based control have been heavily studied in the literature. From the implementation perspective, real-time control systems require timeliness and predictable timing behaviour in addition to logical correctness, and a real-time control system may behave very differently with different software implementations of the control strategies on a digital controller, which typically has limited computing resources. Most current research activities on software implementations concentrate on various scheduling methodologies to ensure the schedulability of multiple control tasks in constrained environments. Recently, more and more real-time control systems are implemented over data networks, leading to increasing interest worldwide in the design and implementation of networked control systems (NCS). Major research activities in NCS include control-oriented and scheduling-oriented investigations. In spite of significant progress in the research and development of real-time control systems, major difficulties exist in the state of the art. A key issue is the lack of integrated design for control development and its software implementation. For control design, the model-based control technique, the current focus of control research, does not work when a good process model is not available or is too complicated for control design. For control implementation on digital controllers running multiple tasks, the system schedulability is essential but is not enough; the ultimate objective of satisfactory quality-of-control (QoC) performance has not been addressed directly. For networked control, the majority of the control-oriented investigations are based on two unrealistic assumptions about the network induced delay. The scheduling-oriented research focuses on schedulability and does not directly link to the overall QoC of the system. General solutions with direct QoC consideration from the network perspective to the challenging problems of network delay and packet dropout in NCS have not been found in the literature. This thesis addresses the design and implementation of real-time control systems with regard to dynamics analysis and integrated design. Three related areas have been investigated, namely control development for controllers, control implementation and scheduling on controllers, and real-time control in networked environments. Seven research problems are identified from these areas for investigation in this thesis, and accordingly seven major contributions have been claimed. Timing behaviour, quality of control, and integrated design for real-time control systems are highlighted throughout this thesis. In control design, a model-free control technique, pattern predictive control, is developed for complex reactive distillation processes. Alleviating the requirement of accurate process models, the developed control technique integrates pattern recognition, fuzzy logic, non-linear transformation, and predictive control into a unified framework to solve complex problems. Characterising the QoC indirectly with control latency and jitter, scheduling strategies for multiple control tasks are proposed to minimise the latency and/or jitter. Also, a hierarchical, QoC driven, and event-triggering feedback scheduling architecture is developed with plug-ins of either the earliest-deadline-first or fixed priority scheduling. Linking to the QoC directly, the architecture minimises the use of computing resources without sacrifice of the system QoC. It considers the control requirements, but does not rely on the control design. For real-time NCS, the dynamics of the network delay are analysed first, and the nonuniform distribution and multi-fractal nature of the delay are revealed. These results do not support two fundamental assumptions used in existing NCS literature. Then, considering the control requirements, solutions are provided to the challenging NCS problems from the network perspective. To compensate for the network delay, a real-time queuing protocol is developed to smooth out the time-varying delay and thus to achieve more predictable behaviour of packet transmissions. For control packet dropout, simple yet effective compensators are proposed. Finally, combining the queuing protocol, the packet loss compensation, the configuration of the worst-case communication delay, and the control design, an integrated design framework is developed for real-time NCS. With this framework, the network delay is limited to within a single control period, leading to simplified system analysis and improved QoC.