The development of embedded system technologies have made it feasible to deploy large-scale sensor and actuator networks. These networks are revolutionizing the way in which we understand, monitor and control complex physical environment, and provide one of the missing connections between the Internet and the physical world. Because of size, form factor and cost considerations, wireless sensor networks suffer from severe resource constraints, such as communication bandwidth and range, computation power, memory and energy. Furthermore, sensor networks are expected to consist of hundreds of sensors in the future. The resource constraints of tiny embedded devices, together with the large network size, create many research challenges which do not appear in traditional networks. In this dissertation, we address the challenges involved in designing robust and scalable sensor network system. In contrast to the flat networking model considered in previous sensor networks research, we propose a hierarchical or hybrid network architecture which is more scalable and robust. Hybrid sensor networks consist of resource-impoverished sensors and resource-rich sensors, called micro-servers. Because of the different capabilities of heterogeneous devices in hybrid sensor networks, there is need for effective deployment and utilization of network resources. Therefore, we introduce resource provisioning and management algorithms to optimize the performance of hybrid sensor networks. The first contribution of this dissertation is the design and implementation of new network architecture and algorithms to address the computation power and memory limitations of tiny embedded devices. The second contribution of this dissertation is the design and evaluation of an Anycast communication paradigm for hybrid sensor and actuator networks. We propose and evaluate a reverse tree-based Anycast mechanism tailored to deal with the unique event dynamics in sensor networks. The third contribution of this dissertation is the design and evaluation of an energy provisioning and management algorithm for hybrid sensor and actuator networks. Our studies show that the location of extra energy-provisioning can affect the lifetime of system dramatically; and hybrid sensor networks are financially cost-effective for a large number of cases which makes them a scalable solution. Together, these contributions enable effective resource provisioning and management in hybrid sensor networks.

This study uses a very high resolution numerical weather prediction (NWP) model to investigate the complex structure and behaviour of cold fronts along the New South Wales coast during the warmer months of the year, the complex interaction between the wind flow and coastlines and elevated areas as well as the lee-trough effect, particularly the way it affects waters off the east coast of Tasmania, The study also investigates the utility of the higher resolution NWP model to better predict wind fields compared to a lower resolution model. The University of New South Wales very high resolution model (HIRES), nested in the Australian Bureau of Meteorology's coarse NWP model (GASP), was run at various horizontal resolutions (from 15 to 25km) in order to investigate the above-mentioned features. It was found to bave very good skill in resolving the features and was also found to be very accurate in the prediction of surface wind fields for various yacht race events out to at least four days ahead. It can be concluded that there is considerable skill in the ability of high-resolution NWP models such as HIRES, to predict the major features of the wind fields over the ocean out to several days ahead. Moreover, it was also able to more accurately simulate the complex structure of the summer-time cool change as it progressed along the NSW coast than the lower resolution model runs. The influence of coastlines, particularly ones with complex topographical features, on the wind flow was demonstrated to a limited extent throughout the study. Finally the following concepts were also verified as a result of the study: - air flow takes the path of least resistance - the shape of topography can help generate local turbulence - the orientation of the wind flow to a mountain range is important in determining turbulent effects. - under certain airflow and stability situations, standing wave activity and a lee trough can be observed in the lee of mountains, hills or even high coastal cliffs.

In this work the phase behaviour of noble gases is studied comprehensively by different molecular simulation methods using different intermolecular potentials. The aim is to investigate three-body effects on the phase behaviour of noble gases. A true two-body potential model (Barker-Fisher-Watts potential) and the three-body potential model (Axilrod-Teller term) have been used. The results obtained from the two-body BFW potential with the three-body Axilrod-Teller potential included for the vapour-liquid and solid-liquid phase equilibrium properties of pure noble gases are compared with the calculations using the Lennard-Jones potential with different suggested parameter values. The results have been compared with experimental data and the best parameter values for simulating the thermodynamic properties of noble gases are found. Three-body effects on the phase behaviour of noble gases are reported for a large range of density, temperature and pressure. Simple relationships have been found between two-body and three-body potential energies for pure fluids and solids. Three-body effects on the vapour-liquid phase equilibrium properties of argon, krypton, xenon and argon-krypton systems are studied by the Gibbs-Duhem integration Monte Carlo method. Three-body effects on the solid-liquid phase equilibrium properties of argon, krypton and xenon are investigated by non-equilibrium and equilibrium molecular dynamics techniques. All the calculations have been compared with experimental data, which show that three-body interactions play an important role in the overall interatomic interactions of noble gases.

Nature and biological systems have provided the basis for many computational models and systems, such as neural computing and evolutionary computation. This thesis examines the vertebrate immune system which formed the original basis for Artificial Immune Systems (AIS). The vertebrate immune system is highly complex and, for the most part, is successful at providing us with protection from harmful stimuli. Such a system is attractive as a model to inspire a computational system as it exhibits many desirable behaviours: adaptability, diversity, robustness, efficiency and multiple layers of detection. There has been an increasing volume of research in the field of artificial immune systems. However, as the field has expanded, immunological analogies have been reduced at the expense of problem specific optimisation. Hence, this thesis takes a different approach and returns to the immune system which initially inspired research in this field. In this thesis a set of key immunological properties based on immune system concepts and mechanisms are formalised in a model for an artificial immune system. This leads to an AIS framework that is more closely aligned with the immune system, and incorporates both innate and adaptive immune concepts. In particular, antigen presenting cells (APCs), major histocompatibility complex (MHC) molecules and T-cells are modelled within the framework. The differential signalling hypothesis is explored as a model for T-cell development, and provides a novel method for T-cell generation within an AIS. Extensive empirical analysis is performed at an individual level to examine the behaviour of the AIS framework components. These results show that the artificial immune system components exhibit similar properties to the real immune components that inspired them. However, the MHC component of the AIS is found to be of limited value within an individual AIS. The AIS framework is subsequently extended to model a population of artificial immune systems. Further empirical analysis is performed at a population level, and MHC is found to improve the adaptability of an evolving population of artificial immune systems within a dynamic environment. Such a model of immune system function is likely to be useful for immunologists, as it could provide a method of examining immune behaviour under various conditions in a cheaper and more rapid manner than in-vivo or in-vitro. Indeed, it may also provide a solution for examining properties that are unable to be tested using these traditional methods. Finally, the results of these empirical findings are discussed in terms of the relevance and applicability of immunological principles with regard to artificial immune systems for real world problems.

Bibliography: leaves 77-79. Uses computer-aided design to improve the design of a partially parallel stump jump mechanism which was initially developed by Riley. Principle aim was to reduce the existing link dimensions of the mechanism so that it can be suitable for use on small tractors.

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A numerical model is developed to estimate wave forces on A-Jacks armor units. The forces include drag, inertia, buoyancy, and slamming as the unit penetrates the free surface. The wave force model is used to determine the rigid body motions of the units. Bulk forces on a matrix of units are also estimated. Wave flume tests are used to provide preliminary verification of the wave force model. The wave force model discretizes the A-Jacks into a number of small elements. The Morison equation is used for submerged elements with stretch linear wave theory employed for wave kinematics. For elements that penetrate the free surface, slamming force calculations are based on the von Karman method. The calculated wave forces are used to determine the rigid body rotation of a single, unrestrained A-Jacks. The axes of rotation are defined by the three contacts between the unit and the under layer. The model allows for an individual A-Jacks unit to rotate with one degree of freedom about the axis of rotation with the minimum stability. Adjacent units do not restrain the rotation and interactions with other units in the matrix are not included. The equation of motion is integrated in time to determine the rotation. This technique is used to determine the incipient motion conditions for a single, unrestrained A-Jacks. This is verified with experimental observations. The wave force model is found to be in agreement with the incipient rotational motion experiment results. The angular velocity at the instant when a lea of the unit rocks back and impacts the under layer can also be used to determine the impact force on the leg. A single, unrestrained A-Jacks is a simplistic idealization. In reality, there is a high degree of interaction among the units. The interaction results in partial sheltering from wave forces and additional motion restraint. The bulk forces on a matrix of A-Jacks units are estimated by applying an empirical factor to the calculated forces to account for the sheltering effects among units. A calibration and preliminary verification of the bulk force models is obtained by measuring forces exerted on a matrix of units mounted on a load-frame. The A-Jacks were subjected to a variety of wave conditions in a 10 m wave flume. The measured bulk force on a matrix of units was fit with the numerical model output using a consistent set of sheltering coefficients. / Graduation date: 2000

Recent concern over the potential environmental impact of highway construction and repair materials on surface and ground waters has lead to extensive laboratory screening and subsequent testing of a set of new materials and waste amended mixes. As part of Phase II of a three-phase project for the National Cooperative Highway Research Program, a fate and transport model for the assessment of this impact has been written. The model predicts concentrations and loads of contaminants as well as toxicities for the leachates in both surface and subsurface environments. The model addresses four specific "reference environments": an impermeable highway surface, a permeable highway surface, a vertical piling, and a filled borehole. Six materials are examined in detail: crumb rubber asphalt concrete. SEMASS asphalt concrete, foundry sand asphalt concrete, ammonical copper zinc arsenate treated wood, and methyl methacrylate deck sealer. A statistical approach to relating toxicity to the concentration of a chemical "surrogate" forms the basis for prediction of toxicity in the leachates. All fate and transport prediction methods are based on physical and mathematical descriptions of the near-highway environment. Surface runoff is calculated using kinematic wave theory coupled with leaching, photolysis and volatilization, flow through pavement cracks is based on continuity, and subsurface transport is based on a plug flow model with linear or Freundlich sorption and biodegradation. Explicit finite difference numerical methods are used for both surface leaching and subsurface transport. A search engine is provided for examination of all laboratory results. / Graduation date: 1999

Forest carnivores such as the fisher have frequently been the target of conservation concern due to their association with older forests and assumed sensitivity to landscape-level habitat alteration. Although the fisher has been extirpated from most of its former range in the western U.S., it is still found throughout much of northwestern California. However, fisher distribution is still poorly known in the majority of this region where surveys have not been conducted. In order to predict fisher distribution across the region, a multiple logistic regression model was created using data from 682 previously surveyed locations and a GIS vegetation coverage created from satellite imagery. A moving-average function was used to derive landscape level indices of vegetation variables from the GIS layer. Moving averages of canopy closure, tree size class, and percent conifer were found to have strong correlations with fisher presence. Regional gradients as represented by either precipitation or a trend surface derived from spatial coordinates were also significant predictors in the model. The model was validated with new data collected from 240 survey locations and proved to be accurate in predicting fisher presence in unsurveyed areas. The model was used to generate hypotheses as to the mechanisms controlling habitat selection and the scales at which these operate and to evaluate the representation of fisher habitat in existing protected areas. These insights may be valuable in designing conservation reserve networks that insure the long-term viability of forest carnivore populations. / Graduation date: 1998

Traditional simulation tools, such as simulators and simulation languages do not support intelligent simulation output analysis and offer little - or no - features to model intelligence within a system. However, in a modern manufacturing environment we often find ourselves facing high flexibility requirements and the need for quick response. We find an increasing number of artificial Intelligence (AI) applications on the shop floor and the need to figure out what is going on in our system - now, not later. Simulation is one tool which is useful to analyze manufacturing systems and make decisions based on the findings. Thus, it is desirable to be able to represent the intelligence we find on the shop floor in our simulation model, as well as an automated output analysis in order to speed up the decision making process. This paper describes the conceptual design and implementation of an AI architecture with the aim to offer a platform where both aspects, representation of intelligence in the system and outside the system (output analysis) can be performed. The architecture is based on Wang's extension (1995) of the simulation environment by Beaumariage (1990) which is implemented in an object-oriented environment. The object-oriented environment also offers an excellent means for implementing the Al architecture. To verify its usefulness two areas of application - priority sequencing at servers and material release - were implemented and several case studies carried out. / Graduation date: 1997