<p>Extrusion Deposition Additive Manufacturing (EDAM) is a process in which fiber-filled thermoplastic polymers are mixed and melted in an extruder and deposited onto a build plate in a layer-by-layer basis. Anisotropy caused by flow-induced orientation of discontinuous fibers along with the non-isothermal cooling process gives rise to internal stresses in printed parts which results in part deformation. The deformation and residual stresses can be abated by modifying the fiber orientation in the extrudate to best suit the print geometry. To that end, the focus of this research is on understanding the effect of fiber orientation state and fiber properties on effective properties of the printed bead and the final deformation of a part. The properties of three different orientation tensors of glass fiber-filled polyamide and carbon fiber-filled polyamide were experimentally and virtually characterized via micromechanics. A thermo-mechanical simulation framework developed in ABAQUS© was used to understand the effects of the varying fiber orientation tensor and fiber properties on the final deformation of printed parts. In particular, a medium-size geometry that is prone to high deformation was simulated and compared among the three orientation tensors and two material systems. This serves to be a good preliminary study to understand microscopic properties induced deformations in EDAM.</p>

The marine current turbine (MCT) is an exciting proposition for the extraction of renewable tidal and marine current power. However, the numerical prediction of the performance of the MCT is difficult due to its complex geometry, the surrounding turbulent flow and the free surface. The main purpose of this research is to develop a computational tool for the simulation of a MCT in turbulent flow and in this thesis, the author has modified a 3D Large Eddy Simulation (LES) numerical code to simulate a three blade MCT under a variety of operating conditions based on the Immersed Boundary Method (IBM) and the Conservative Level Set Method (CLS). The interaction between the solid structure and surrounding fluid is modelled by the immersed boundary method, which the author modified to handle the complex geometrical conditions. The conservative free surface (CLS) scheme was implemented in the original Cgles code to capture the free surface effect. A series of simulations of turbulent flow in an open channel with different slope conditions were conducted using the modified free surface code. Supercritical flow with Froude number up to 1.94 was simulated and a decrease of the integral constant in the law of the wall has been noticed which matches well with the experimental data. Further simulations of the marine current turbine in turbulent flow have been carried out for different operating conditions and good match with experimental data was observed for all flow conditions. The effect of waves on the performance of the turbine was also investigated and it has been noticed that this existence will increase the power performance of the turbine due to the increase of free stream velocity.

From the safety point of view, the bus stop is perhaps the most important part of the Bus Public Transport System, as it represents the point where bus passengers may interact directly with other road users and create conflicting situations leading to traffic accidents. For example, travellers could be struck walking to/from or boarding/alighting a bus. At these locations, passengers become pedestrians and at some stage crossing busy arterial roads at the bus stop in areas or at objects of main attraction usually outside of pedestrian designated facilities such as signal controlled intersections, zebra and pelican crossings. Pedestrian exposure to risk or risk-taking occurs when people want to cross the road in front of the stopped bus, at the rear of the bus or between the buses, particularly where bus stops are located on two-way roads (i.e. within the mid-block of the road with side streets, at non-signalised cross-section). However, it is necessary to have a better understanding of the pedestrian road-crossing risk exposure (pedestrian crossing distraction, obscurity and behaviour) within bus stop zones so that it can be incorporated into new design, bus stop placement, and evaluation of traffic management schemes where bus stop locations will play an increasingly important role. A full range of possible incidental interactions are presented in a tabular model that looks at the most common interacting traffic movements within bus stop zones. The thesis focused on pedestrian safety, discusses theoretical foundations of bus stops, and determines the types of accident risks between bus travellers as pedestrians and motor vehicles within the zones of the bus stop. Thus, the objectives of this thesis can be summarized as follows: (I) - Classification of bus stops, particularly according to objects of main attraction (pedestrian-generating activities); (II) - Analysis of traffic movement and interactions as an accident/risk exposure in the zone of bus stops with respect to that structure; (III) - Categorizing traffic accident in the vicinity of bus stops, and to analyse the interactions (interacting movements) that occur within bus stop zones in order to discover the nature of problems; (IV) - Formulation of tabular (pedestrian traffic accident prediction) models/forms (based on traffic interactions that creating and causing possibilities of accident conflict) for practical statistical methods of those accidents related to bus stop, and; (V) - Safety aspects related to the micro-location of bus stops to assist in the micro-location design, operations of bus stop safety facilities and safer pedestrian crossing for access between the bus stop and nearby objects of attraction. The scope of this thesis focuses on the theoretical foundation of bus stop microâ??location in areas of main attractions or at objects of main attraction, and traffic accident risk types as they occur between travellers as pedestrians and vehicle flow in the zone of the bus stop. The knowledge of possible interactions leads to the identification of potential conflict situations between motor vehicles and pedestrians. The problems discussed for each given conflict situation, has a great potential in increasing the knowledge needed to prevent accidents and minimise any pedestrian-vehicle conflict in this area and to aid in the development and planning of safer bus stops.

One of the established strengths of human tutors is their ability to recognise and adapt to the emotions of students. This is a skill that has traditionally been lacking from Intelligent Tutoring Systems (ITSs); despite their ability to intelligently model and adapt to aspects of the student’s cognitive state, ITSs are generally completely unable to detect or adapt to aspects of the student’s affective state. In response to this shortcoming, this thesis explores the pioneering development of an emotion-sensitive ITS. With the empathy of effective human tutors as our blueprint, we investigate how an artificial tutor should adapt to the affective state of students, and develop an original affective tutoring strategies method. As a validation of the feasibility of an emotion-sensitive tutoring system, we implement and test our method in a functional Affective Tutoring System (ATS) for counting and addition, Easy with Eve, featuring an empathetic animated pedagogical agent, Eve. Eve is able to detect student affect using an in-house real time facial expression analysis system. To inform the system’s adaptation to student affect, the novel method for student modelling and emotion-sensitive tutoring strategies has been developed using a fuzzy, case-based reasoning approach. This approach is used to mine data about human tutor adaptations to student affect that was generated by an observational study of human tutors that was carried out in a local primary school. To test the impact of emotion detection and the presence of the animated agent, four different versions of the ATS were tested in local primary schools with a total of 59 participants. The findings from the study indicate that adding the detection of facial expressions to the student model did not improve student short-term performance, but there was mixed evidence that the presence of the animated agent Eve may cause students to perceive the system slightly more positively (a persona effect). This effect was marginally greater when the animated agent was enabled to detect and adapt to the affective state of students, which tentatively shows that emotion detection in an ATS may have a positive effect on student motivation.

The LEGO® MINDSTORMS® toolkit can be used to help students learn basic programming and engineering concepts. Software that is widely used with LEGO MINDSTORMS is ROBOLAB, developed by Professor Chris Rogers from Tufts University, Boston, United States. It has been adopted in about 10,000 schools in the United States and other countries. It is used to program LEGO MINDSTORMS robotics in its icon-based programming environment. However, this software does not provide debug features for LEGO MINDSTORMS programs. Users cannot test the program before downloading it into LEGO robotics hardware. In this project, we develop a simulator for LEGO MINDSTORMS to simulate the motions of LEGO robotics in a virtual 3D environment. We use ODE (Open Dynamic Engine) and OpenGL, combined with ROBOLAB. The simulator allows users to test their ROBOLAB program before downloading it into the LEGO MINDSTORMS hardware. For users who do not have the hardware, they may use the simulator to learn ROBOLAB programming skills which may be tested and debugged using the simulator. The simulator can track and display program execution as the simulation runs. This helps users to learn and understand basic robotics programming concepts. An introduction to the overall structure and architecture of the simulator is given and is followed by a detailed description of each component in the system. This presents the techniques that are used to implement each feature of the simulator. The discussions based on several test results are then given. This leads to the conclusion that the simulator is able to accurately represent the actions of robots under certain assumptions and conditions.

This thesis investigates a method for tackling the verification of parametric systems, systems whose behaviour may depend on the value of one or more parameters. The range of allowable values for such parameters may, in general, be large or unknown. This results in a large number of instances of a system that require verification, one instance for each allowable combination of parameter values. When one or more parameters are unbounded, the family of systems that require verification becomes infinite. Computer protocols are one example of such parametric systems. They may have parameters such as the maximum sequence number or the maximum number of retransmissions. Traditional protocol verification approaches usually only analyse and verify properties of a parametric system for a small range of parameter values. It is impossible to verify in this way every concrete instance of an infinite family of systems. Also, the number of reachable states tends to increase dramatically with increasing parameter values, and thus the well known state explosion phenomenon also limits the range of parameters for which the system can be analysed. In this thesis, we concentrate on the parametric verification of the Stop-and-Wait Protocol (SWP), an elementary flow control protocol. We have used Coloured Petri Nets (CPNs) to model the SWP, operating over an in-order but lossy medium, with two unbounded parameters: the maximum sequence number; and the maximum number of retransmissions. A novel method has been used for symbolically representing the parametric reachability graph of our parametric SWP CPN model. This parametric reachability graph captures exactly the infinite family of reachability graphs resulting from the infinite family of SWP CPNs. The parametric reachability graph is represented symbolically as a set of closed-form algebraic expressions for the nodes and arcs of the reachability graph, expressed in terms of the two parameters. By analysing the reachability graphs of the SWP CPN model for small parameter values, structural regularities in the reachability graphs were identified and exploited to develop the appropriate algebraic expressions for the parametric reachability graph. These expressions can be analysed and manipulated directly, thus the properties that are verified from these expressions are verified for all instances of the system. Several properties of the SWP that are able to be verified directly from the parametric reachability graph have been identified. These include a proof of the size of the parametric reachability graph in terms of both parameters, absence of deadlocks (undesired terminal states), absence of livelocks (undesirable cycles of behaviour from which the protocol cannot escape), absence of dead transitions (actions that can never occur) and the upper bounds on the content of the underlying communication channel. These are verified from the algebraic expressions and thus hold for all parameter values. Significantly, language analysis is also carried out on the parametric SWP. The parametric reachability graph is translated into a parametric Finite State Automaton (FSA), capturing symbolically the infinite set of protocol languages (i.e. sequences of user observable events) by means of similar algebraic expressions to those of the parametric reachability graph. Standard FSA reduction techniques were applied in a symbolic fashion directly to the parametric FSA, firstly to obtain a deterministic representation of the parametric FSA, then to obtain an equivalent minimised FSA. It was found that the determinisation procedure removed the effect of the maximum number of retransmissions parameter, and the minimisation procedure removed the effect of the maximum sequence number parameter. Conformance of all instances of the SWP over both parameters to its desired service language is proved. The development of algebraic expressions to represent the infinite class of Stop-and-Wait Protocols, and the verification of properties (including language analysis) directly from these algebraic expressions, has demonstrated the potential of this method for the verification of more general parametric systems. This thesis provides a significant contribution toward the development of a general parametric verification methodology.

Fusion Motion Capture (FMC), a wearable motion capture system was developed, and applied to the optimisation of athlete performance in alpine ski racing. In what may be a world first, the three-dimensional movements of a skilled athlete (with less than 20 FIS1 points) skiing through a complete training giant slalom racecourse were analysed. FMC consists of multiple light weight sensors attached to the athlete including inertial measurement units (IMUs), pressure sensitive insoles and a global position system (GPS) receiver. The IMUs contain accelerometers, gyroscopes, and magnetometers. Limb orientation and location are obtained by mathematically combining the most reliable data from each sensor using fusion algorithms developed by the author. FMC fuses the signals from the IMUs and GPS without the need for the post filtering, usually applied to motion capture data, and therefore, maintains maximum bandwidth. The FMC results were stable and relatively independent of motion type and duration unlike other inertial systems available in 2005, when the research was initiated. Analysis of data collected from an athlete skiing giant slalom contradict the traditional „going straight turning short? race strategy. The shortest path may not always be the fastest. Instead each gate has a different optimum approach arc. Optimum turn radius increases with both increasing speed and increasing terrain slope. The results also contradict laboratory measurements of ski/snow sliding friction and suggest that snow resistance in giant slalom is of similar importance to wind drag. In addition to gravity, the athlete increased speed using the techniques of „lateral projection? and „pumping?. Race performance was determined from the analysis of the athlete skiing through the entire course. FMC proved, therefore, to be more suitable than traditional optical systems that are practically limited to capturing small sections of a race course. The athlete experienced high and rapidly fluctuating torques about all three axes of the lower joints. This information could be useful in designing training programmes racecourses and equipment to reduce knee injuries. Data driven animations and colour coded force vector diagrams were developed to enhance athlete feedback. Inline skating data was also analysed.

This thesis considers various aspects of the use of ground-based methods and remote sensing of Biological Soil Crusts (BSC). They are mostly distributed in winter rainfall dominated areas such as those at Middleback Field Centre (MFC) in South Australia. They can be used potentially as an indicator of rangeland condition by estimating grazing pressure (trampling). Two BSC based indicators for rangeland condition assessment are species composition and cover. While there is strong agreement that BSC composition is a good indicator, there is less agreement that BSC cover alone is a good indicator. Although BSC have been included in previous remotely-sensed studies, their spectral characteristics, and hence their contributions to remotely-sensed spectral signatures, are not well known. Data collection methods were refined for suitable method selection, stratification and site characterization, and morphological/ functional group classification. Cover data of BSC were collected using a 100 m line-intercept method on the stratified land units and statistical analyses were based on the cover variance analyses. Spectra of BSC groups were collected and characterized for different remote sensing indices. Five grazing gradient models based on collected spectra were developed for the evaluation of BSC effect on remotely-sensed data. Both existing and newly developed remote sensing indices were examined for BSC detection. Sampling for cover of BSC in the field showed that there is indeed a detectable change with distance from water, suggesting that BSC cover can be used as an indicator of rangeland condition, provided that appropriate stratification of the study sites is carried out prior to sampling, and spectral differences in morphological and functional groups are taken into account. Spectral analysis of BSC components showed that different classes of organisms in the crusts have different spectral characteristics, and in particular, that the (commonly-used) perpendicular vegetation index (PD54) is not suitable for detecting BSC. On the other hand, ground-level spectral modelling showed that the Normalized Difference Vegetation Index (NDVI) and Soil Stability Index (SSI) did show a distinguishable contribution from BSC. A procedure for detecting cover of BSC was developed for image taken during the period after an effective rain, in contrast to the normal practice of selecting images of dry surfaces for interpretation. The most suitable intervals appears to be 2-4 days after rain in late autumn, winter and early spring. Of the existing indices, the SSI is the best for estimating cover of BSC from Landsat images. However, eight new indices, specifically designed for detection of BSC were developed during the cource of this work. The best results were obtained for indices using using the middle-infrared bands. These results are promising for application to rangeland monitoring and suggest that BSC cover is an important indicator of rangeland condition if appropriate stratification, classification and data-collection methods are used. The effects of BSC cover on a remotely-sensed method are considerable, and thus they can not be neglected during image interpretation. There are different phenological patterns for BSC, annual and perennial elements, thus there is the possibility for the selection of imagery based on each phenological stage to detect these elements. Application of certain indices such as the PD54 may create mis-estimation of land covers. Although some of the existing and newly developed indices had significant results for BSC cover estimation, there is a requirement for a standalone remotely-sensed method to conclude the best index.

This thesis details the development of a model of driver behaviour at railway level crossings that allows the probability of an accident under different conditions and interventions to be calculated. A method for classifying different crossings according to their individual risk levels is also described.

Agent-based systems usually operate in real-time, stochastic and dynamic environments. Many theoretical and applied techniques have been applied to the investigation of agent architecture with respect to communication, cooperation, and learning, in order to provide a framework for implementing artificial intelligence and computing techniques. Intelligent agents are required to be able to adapt and learn in uncertain environments via communication and collaboration (in both competitive and cooperative situations). The ability of reasoning and learning is one fundamental feature for intelligent agents. Due to the inherent complexity, however, it is difficult to verify the properties of the complex and dynamic environments a priori. Since analytic techniques are inadequate for solving these problems, reinforcement learning (RL) has appeared as a popular approach by mapping states to actions, so as to maximise the long-term rewards. Computer simulation is needed to replicate an experiment for testing and verifying the efficiency of simulation-based optimisation techniques. In doing so, a simulation testbed called robot soccer is used to test the learning algorithms in the specified scenarios. This research involves the investigation of simulation-based optimisation techniques in agent-based systems. Firstly, a hybrid agent teaming framework is presented for investigating agent team architecture, learning abilities, and other specific behaviors. Secondly, the novel reinforcement learning algorithms to verify goal-oriented agents; competitive and cooperative learning abilities for decision-making are developed. In addition, the function approximation technique known as tile coding (TC), is used to avoid the state space growing exponentially with the curse of dimensionality. Thirdly, the underlying mechanism of eligibility traces is analysed in terms of on-policy algorithm and off-policy algorithm, accumulating traces and replacing traces. Fourthly, the "design of experiment" techniques, such as Simulated Annealing method and Response Surface methodology, are integrated with reinforcement learning techniques to enhance the performance. Fifthly, a methodology is proposed to find the optimal parameter values to improve convergence and efficiency of the learning algorithms. Finally, this thesis provides a serious full-fledged numerical analysis on the efficiency of various RL techniques.