Soft computing is a concept that has come into prominence in recent times and its application to power system analysis is still more recent. This thesis explores the application of soft computing techniques in the area of voltage stability of power systems. Soft computing, as opposed to conventional “hard” computing, is a technique that is tolerant of imprecision, uncertainty, partial truth and approximation. Its methods are based on the working of the human brain and it is commonly known as artificial intelligence. The human brain is capable of arriving at valid conclusions based on incomplete and partial data obtained from prior experience. It is an approximation of this process on a very small scale that is used in soft computing. Some of the important branches of soft computing (SC) are artificial neural networks (ANNs), fuzzy logic (FL), genetic computing (GC) and probabilistic reasoning (PR). The soft computing methods are robust and low cost. It is to be noted that soft computing methods are used in such diverse fields as missile guidance, robotics, industrial plants, pattern recognition, market prediction, patient diagnosis, logistics and of course power system analysis and prediction. However in all these fields its application is comparatively new and research is being carried out continuously in many universities and research institutions worldwide. The research presented in this thesis uses the soft computing method of Artificial Neural Networks (ANN’s) for the prediction of voltage instability in power systems. The research is very timely and current and would be a substantial contribution to the present body of knowledge in soft computing and voltage stability, which by itself is a new field. The methods developed in this research would be faster and more economical than presently available methods enabling their use online.

This thesis describes an investigation into the flow behaviour of particulate solids and capsules in wood pulp fibre suspensions. Emphasis is placed on measuring pipe friction loss and stability of solids-fibre slurries and fibre-capsule mixtures in straight horizontal pipes. It is shown that low concentrations (1-3 %v) of wood pulp fibre form a structured carrier fluid with ability to support particles while behaving like a liquid of low viscosity. At moderate flow velocities fibres damp turbulence and friction losses become lower than water. If solids are preferentially injected into the fibre suspension as a central core, or in a capsule as dry solids, pipe friction loss is reduced further, as is pipe wear. At very low fibre concentrations (<1%v), fibres reduce the friction loss of conventional solid-water mixtures and act as a drag reducing additive. The network strength properties of five wood fibre suspensions are reported and their application to slurry flow is discussed. Settling data for particulate solids, coherent dense-phase cores and capsules are presented and various mechanisms of support are described. Two flow techniques for transporting coarse and dense-phase particle suspensions are proposed, along with strategies for injecting solid particulates into a pipeline. Pipe friction loss data are presented for solids-fibre mixtures of wood chips (7-15 mm), coarse (+2-10 mm) and fine (+0.5-1.0 mm) coal, sand (+0.32-2.0 mm), iron ore (+0.05-0.28 mm), and cylindrical capsules (loaded with dry solids) flowing in 54, 79 and 101.6 mm diameter PVC pipes. Some pipe friction loss data are presented for solids transported as a central core supported by an annulus of fibre suspension. The key flow parameters are also optimized and a preliminary cost comparison is made. Coarse coal suspensions (up to 4O %v) with fibre concentrations of 0.7 to 1.0 percent have been shown to exhibit friction losses about 40 percent below that of the equivalent coalwater slurry. Adding 0.8 percent fibre to water is shown to reduce capsule friction head loss up to 50 percent.

This thesis describes an investigation into the flow behaviour of particulate solids and capsules in wood pulp fibre suspensions. Emphasis is placed on measuring pipe friction loss and stability of solids-fibre slurries and fibre-capsule mixtures in straight horizontal pipes. It is shown that low concentrations (1-3 %v) of wood pulp fibre form a structured carrier fluid with ability to support particles while behaving like a liquid of low viscosity. At moderate flow velocities fibres damp turbulence and friction losses become lower than water. If solids are preferentially injected into the fibre suspension as a central core, or in a capsule as dry solids, pipe friction loss is reduced further, as is pipe wear. At very low fibre concentrations (<1%v), fibres reduce the friction loss of conventional solid-water mixtures and act as a drag reducing additive. The network strength properties of five wood fibre suspensions are reported and their application to slurry flow is discussed. Settling data for particulate solids, coherent dense-phase cores and capsules are presented and various mechanisms of support are described. Two flow techniques for transporting coarse and dense-phase particle suspensions are proposed, along with strategies for injecting solid particulates into a pipeline. Pipe friction loss data are presented for solids-fibre mixtures of wood chips (7-15 mm), coarse (+2-10 mm) and fine (+0.5-1.0 mm) coal, sand (+0.32-2.0 mm), iron ore (+0.05-0.28 mm), and cylindrical capsules (loaded with dry solids) flowing in 54, 79 and 101.6 mm diameter PVC pipes. Some pipe friction loss data are presented for solids transported as a central core supported by an annulus of fibre suspension. The key flow parameters are also optimized and a preliminary cost comparison is made. Coarse coal suspensions (up to 4O %v) with fibre concentrations of 0.7 to 1.0 percent have been shown to exhibit friction losses about 40 percent below that of the equivalent coalwater slurry. Adding 0.8 percent fibre to water is shown to reduce capsule friction head loss up to 50 percent.

This thesis describes an investigation into the flow behaviour of particulate solids and capsules in wood pulp fibre suspensions. Emphasis is placed on measuring pipe friction loss and stability of solids-fibre slurries and fibre-capsule mixtures in straight horizontal pipes. It is shown that low concentrations (1-3 %v) of wood pulp fibre form a structured carrier fluid with ability to support particles while behaving like a liquid of low viscosity. At moderate flow velocities fibres damp turbulence and friction losses become lower than water. If solids are preferentially injected into the fibre suspension as a central core, or in a capsule as dry solids, pipe friction loss is reduced further, as is pipe wear. At very low fibre concentrations (<1%v), fibres reduce the friction loss of conventional solid-water mixtures and act as a drag reducing additive. The network strength properties of five wood fibre suspensions are reported and their application to slurry flow is discussed. Settling data for particulate solids, coherent dense-phase cores and capsules are presented and various mechanisms of support are described. Two flow techniques for transporting coarse and dense-phase particle suspensions are proposed, along with strategies for injecting solid particulates into a pipeline. Pipe friction loss data are presented for solids-fibre mixtures of wood chips (7-15 mm), coarse (+2-10 mm) and fine (+0.5-1.0 mm) coal, sand (+0.32-2.0 mm), iron ore (+0.05-0.28 mm), and cylindrical capsules (loaded with dry solids) flowing in 54, 79 and 101.6 mm diameter PVC pipes. Some pipe friction loss data are presented for solids transported as a central core supported by an annulus of fibre suspension. The key flow parameters are also optimized and a preliminary cost comparison is made. Coarse coal suspensions (up to 4O %v) with fibre concentrations of 0.7 to 1.0 percent have been shown to exhibit friction losses about 40 percent below that of the equivalent coalwater slurry. Adding 0.8 percent fibre to water is shown to reduce capsule friction head loss up to 50 percent.

This thesis describes an investigation into the flow behaviour of particulate solids and capsules in wood pulp fibre suspensions. Emphasis is placed on measuring pipe friction loss and stability of solids-fibre slurries and fibre-capsule mixtures in straight horizontal pipes. It is shown that low concentrations (1-3 %v) of wood pulp fibre form a structured carrier fluid with ability to support particles while behaving like a liquid of low viscosity. At moderate flow velocities fibres damp turbulence and friction losses become lower than water. If solids are preferentially injected into the fibre suspension as a central core, or in a capsule as dry solids, pipe friction loss is reduced further, as is pipe wear. At very low fibre concentrations (<1%v), fibres reduce the friction loss of conventional solid-water mixtures and act as a drag reducing additive. The network strength properties of five wood fibre suspensions are reported and their application to slurry flow is discussed. Settling data for particulate solids, coherent dense-phase cores and capsules are presented and various mechanisms of support are described. Two flow techniques for transporting coarse and dense-phase particle suspensions are proposed, along with strategies for injecting solid particulates into a pipeline. Pipe friction loss data are presented for solids-fibre mixtures of wood chips (7-15 mm), coarse (+2-10 mm) and fine (+0.5-1.0 mm) coal, sand (+0.32-2.0 mm), iron ore (+0.05-0.28 mm), and cylindrical capsules (loaded with dry solids) flowing in 54, 79 and 101.6 mm diameter PVC pipes. Some pipe friction loss data are presented for solids transported as a central core supported by an annulus of fibre suspension. The key flow parameters are also optimized and a preliminary cost comparison is made. Coarse coal suspensions (up to 4O %v) with fibre concentrations of 0.7 to 1.0 percent have been shown to exhibit friction losses about 40 percent below that of the equivalent coalwater slurry. Adding 0.8 percent fibre to water is shown to reduce capsule friction head loss up to 50 percent.

This thesis describes the design and application of a virtual reality simulator for orthopaedic surgeryof the proximal femur. The aim of the research was to create a simulator with the followingattributes; could be used within the current public hospital setting, reflected the perceived needs ofthe local orthopaedic community, provided surgically relevant feedback about aspects of technicalability to orthopaedic surgical trainees and the training committee, allowed practice of operativetasks which for reasons of radiation exposure could otherwise not occur, was validated, and couldbe developed further for other operations. The ultimate aim of the simulator is to allow trainees topractice aspects of surgical treatment such that their care of real patients is improved. The novel aspect of this work has been the development of a simulator which allows the trainee toperform all the steps required for two surgical procedures; namely hip fracture fixation and pinningof slipped femoral capital epiphyses. The simulator runs on the computers found within the publichospital as it does not require expensive hardware such as haptic (force feedback) devices. Resultsfrom the simulator mimic real world measurements which are seldom available to trainees asfeedback to enable them to practice their craft. A survey of the New Zealand orthopaedic surgeons and advanced trainees showed this communitywas generally supportive of simulation, though only 4 respondents had previous experience with asurgical simulator. The task of practicing angulation/spatial orientation was thought most suitablefor simulation, which is the task which the simulator specifically allows trainees to practice. Morerecently qualified surgeons were more likely to agree that simulation was an effective way topractice surgical procedures. Validation of the simulator was tested in two experiments. The simulator was shown to have facevalidity; i.e. a realistic representation of the operating room. This result was obtained by surveyingusers who had completed a number of virtual operations. Construct validity was assessed by thesimulator’s ability to identify between groups of users with differing levels of real surgicalexperience. The simulator was able to discriminate medical students from orthopaedic trainees,despite the medical students’ greater ability in computer-gaming. Advanced trainees generallyperformed better than basic trainees, though in the limited number of trainees available significancewas not reached. Finally the simulator was developed further to allow all advanced trainees within New Zealand tocomplete virtual pin placement of a slipped capital femoral epiphysis. This demonstrated thefeasibility of using the simulator for assessment of trainees within their normal training weekend. Italso revealed different operating styles, and showed how these differing styles do not correlate withthe accuracy with which the final screw is placed.

This thesis presents the results of developing road pavement deterioration models for the State Highway network in New Zealand pavement deterioration models are an integral part of pavement management systems, which are used to forecast long-term maintenance needs and funding requirements on a road network. As part of this research, a Long-term Pavement Performance (LTPP) programme has been established on 63 sections of the State Highways. These sections are representative of typical road sections and climatic conditions on New Zealand roads. Data collection on these sections is undertaken on an annual basis and consists of high accuracy manual measurements. These measurements include road roughness, rutting, visual defect identification and strength testing with a Falling Weight Deflectometer. Based on the LTPP data, new model formats for New Zealand conditions were developed including a crack initiation model and a three-stage rut progression model. The rut progression model consists of three stages, initial densification, stable rut growth and a probabilistic model to predict accelerated rut progression. The continuous probabilistic model developed predicts the initiation of pavement failure events such as crack initiation and accelerated rutting. It has been found that this model type has a strong agreement with actual pavement behaviour as it recognises a distribution of failure on roads rather than failure occurring at an particular point in time, namely, a year. The modelling of rut progression in the three stages including, initial densification, stable rut progression and accelerated rutting has resulted in a significant increased understanding of this defect, especially for thin flexible chip seal pavements. It has been established that the in-service performance of these pavements is relatively predictable. However, incorporating both the in-service performance and the failure of pavements into one model was unrealistic. Therefore, by having the different stages of rutting, resulted into a more accurate forecasting of this defect. Although this research has covered the two priority pavement models including cracking and rutting prediction, it has established the model framework for other pavement models to be developed. As more data become available, further work can be undertaken to refine the models and to extend the research into the performance of alternative construction materials.

An efficient finite element method is developed to model the spreading of excitation in ventricular myocardium by treating the thin region of rapidly depolarizing tissue as a propagating wavefront. The model is used to investigate the excitation sequence in the full canine ventricular myocardium. The solution to an eikonal–curvature equation for excitation time is shown to satisfy a reaction–diffusion equation for the bidomain myocardial model at the wavefront, while the solution to an eikonal–diffusion equation approximately satisfies the reaction–diffusion equation in the vicinity of the wavefront. The features of these two eikonal equations are discussed. A Petrov–Galerkin finite element method with cubic Hermite elements is developed to solve the eikonal–diffusion equation. The oscillatory errors seen when using the Galerkin weighted residual method with high mesh Péclet numbers are avoided by supplementing the Galerkin weights with C⁰ continuous functions based on derivatives of the interpolation functions. The ratio of the Galerkin and supplementary weights is a function of the Péclet number such that, for one-dimensional propagation, the error in the solution is within a small constant factor of the optimal error achievable in the trial space. An additional noinflow boundary term is developed to prevent spurious excitation initiating on the boundary. The need for discretization in time is avoided by using a continuation method to gradually introduce the non-linear term of the governing equation. A small amount of artificial diffusion is sometimes necessary. Simulations of excitation are performed using a model of the anisotropic canine ventricular myocardium with 23.55 degrees of freedom for the dependent variable, and results are compared with reported experimental observations. When it was assumed that Purkinje fibres influence propagation only on the endocardial surface, excitation of the entire myocardium was completed in 56 ms. Altering material parameters to represent penetration of the Purkinje fibres beneath the left endocardial surface reduced the completion time to 48 ms. Modelling the effects of the laminar structure of myocardium by reducing the propagation speed by 40% in the direction normal to the layers delayed completion of excitation by only 4%.

The deployment of third generation (3G) cellular systems is resulting in a transition from cellular systems that predominantly carry constant-bit-rate (CBR) voice traffic to multi-service packet based systems that predominantly carry variable-bit-rate (VBR) traffic. With 3G DS-CDMA cellular systems there is a direct relationship between user traffic and propagation dependent performance as additional traffic causes increased system interference. This thesis investigates the impact of VBR traffic on the propagation dependent performance of DS-CDMA cellular systems that utilise frame-by-frame dynamic resource allocation on the radio channel. A DS-CDMA cellular system model is developed and the downlink performance of both outdoor macro-cellular and indoor pico-cellular systems is evaluated with a variety of traffic types. Both traffic scheduling performance and propagation dependent performance are evaluated as the two are inter-linked. Scenarios are identified where propagation dependent performance is sensitive to the statistical properties of the user traffic streams and it is shown that a significant performance difference potentially exists between different traffic types when the number of users per cell is low. When a significant performance difference does exist, burstier more variable traffic generally results in superior propagation dependent performance. The base transceiver station (BTS) transmitter power mean and variance provides a good indication of the level of propagation dependent performance regardless of the specific traffic type. Traffic scheduling policies that deliberately reduce the variability of user traffic streams are considered and in terms of propagation dependent performance these are shown to have a minimal impact on the performance difference between different traffic types. The implications of VBR traffic on DS-CDMA cellular system design are outlined and it is shown that VBR traffic can be approximated as CBR traffic in many scenarios and this is a convenient approximation as it simplifies system design and detailed traffic models do not need to be developed.

A system was developed with the aim of demonstrating that the tedious tasks of classifying and counting pollen on slides could be performed automatically to a standard comparable with that of human experts. Automation of pollen classification and counting will advance the science and range of applications of palynology. The system developed is a completely functioning prototype. After initial set up and training it is automatic in operation. System tests have demonstrated that the concept is viable and that the prototype developed is at a stage that it is of practical use to palynologists. There are opportunities for improvements and added functionality. Now that the system is developed and characterised, it provides a benchmark for gauging the efficacy of future improvements and adaptations. The system is presently adaptable to many different classification problems within palynology and would be adaptable for other automated microscopic classification or imaging tasks.