Infrastructure Engineering - Theses

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    Evaluating cultural learning in virtual environments
    Champion, Erik Malcolm ( 2006)
    There is still a great deal of opportunity for research on contextual interactive immersion in virtual heritage environments. The general failure of virtual environment technology to create engaging and educational experiences may be attributable not just to deficiencies in technology or in visual fidelity, but also to a lack of contextual and performative-based interaction, such as that found in games. This thesis will suggest improvements will result from more research on the below issues: 1. Place versus Cyberspace: What creates a sensation of place (as a cultural site) in a virtual environment in contradistinction to a sensation of a virtual environment as a collection of objects and spaces? 2. Cultural Presence versus Social Presence and Presence: Which factors help immerse people spatially and thematically into a cultural learning experience? 3. Realism versus Interpretation: Does an attempt to perfect fidelity to sources and to realism improve or hinder the cultural learning experience? 4. Education versus Entertainment: Does an attempt to make the experience engaging improve or hinder the cultural learning experience? This doctoral thesis outlines a theoretical definition of place, culture, and presence that may become a matrix for virtual environment design as well as a discussion of the advantages and disadvantages of appropriating game-style interaction to enhance engagement. A virtual environment was built using Adobe Atmosphere to test whether cultural understanding and engagement can be linked to the type of interaction offered. The thesis also includes a survey of evaluation mechanisms that may be specifically suitable for virtual heritage environments. In its review of appropriate methodology, the thesis suggests new terms and criteria to assess the contextual appropriateness of various evaluation methods, and provides seven schematic examples of game-style plot devices that lend themselves to evaluation. The test-bed is the evaluation of a virtual archaeology project in Palenqué Mexico using theories of cultural immersion as well as computer game technology and techniques. The case study of Palenqué involved five types of evaluation specifically chosen to assess cultural awareness and understanding gained from different forms of interaction in a virtual heritage environment.
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    Technical and financial feasibility of a solar dryer in Bhutan
    LHENDUP, TSHEWANG ( 2005)
    The technical and financial performance of an existing solar crop dryer at Khao-kor, Thailand has been evaluated for possible replication in Bhutan. The complete dryer system has been modelled using TRNSYS and the collector area was optimised to give minimum drying cost. From the evaluation, the average collector, pick-up and system efficiencies were found as 44%, 23% and 18% respectively. The solar contribution to the load is 33% when the dryer is used for 304 days in a year. Chilli and beef were selected as products to be dried as they are an integral part of Bhutan’s dishes. The drying cost is US $ 7.94 and 5.96 per kg of dry matter for chilli and beef respectively using the solar dryer system. The corresponding costs using an electric heating system is US $ 7.76 and 6.25 per kg of dry matter for chilli and beef respectively. The solar dryer system was found to be cheaper compared to an electric heating system, however, from the commercial point of view, without any incentives, both the systems are financially non-viable in Bhutan. Nevertheless, the solar dryer system is more attractive than the electric heating system as its NPV at 13% real discount rate is higher.
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    Statistical-dynamical modelling of catchment water balance: climatic and vegetation controls on hydrological fluxes
    Potter, Nicholas Jan ( 2005)
    The prediction or modelling of catchment water balance is a fundamental hydrological question. So many natural resource management problems rely on accurate modelling of catchment water yield. Both Australian and global water resources are likely to face new and increased pressures in the future as a result of land-use changes, climate change and increased demand for water from both urban and agricultural users. However, the variability of catchment water balance, as well as the sources and timescales of this variability, still remains insufficiently understood. The principal aim of this thesis is an analysis of the water balance of Australian catchments. Using a variety of models, particularly recently developed probabilistic soil-moisture accounting models, catchment water balance and soil moisture variability are examined at different timescales, with particular emphasis on the mean annual timescale of catchment water balance. Recently published stochastic soil-moisture accounting models are presented in detail. This survey highlights the assumptions of the models, the theoretical and observational background to these assumptions, as well as the solutions, limitations and possibilities for improvement of the models. These models are then compared with observational data, and further extensions and solutions to some of the models are presented and discussed. Water balance variability at other timescales is also considered, by testing and extending theoretical hydrological models, resulting in a clearer understanding of the relative roles of climate, soil and vegetation to the variability of catchment water balance.
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    GPS structural deformation monitoring: the mid-height problem
    Raziq, Noor ( 2008)
    GPS has been used to monitor engineering structures for a number of reasons. One important reason for monitoring high rise buildings (and other engineering structures) is their safety assessment in events of extreme loading, such as earthquakes and storms. Decisions must be made as soon as possible, whether to allow re-occupation of such buildings, or to assess them for further damage. The time required to reach such decisions is cost-critical, both for the building owner or manager and for the agency doing the assessment. Peak inter-storey drift ratio and detection of permanent damage are some of the damage assessment parameters recommended by assessment agencies. Traditionally, accelerometers have been used to monitor these parameters. Accelerometers measure accelerations which are double-integrated to get displacements. These double integrated displacements are then used for computing the inter-storey drift ratios and locating permanent damage. Displacements obtained by double-integration and inter-storey drift ratios by subtraction of these displacements, are often erroneous and unreliable and direct measurement of displacement is preferred. Direct measurement of displacement is required at a number of points along the height of the building. For example, for computing inter-storey drift ratios, measurements of displacement at both the floor level and roof level are required. Such points on buildings and other engineering structures of vertical profile are termed as mid-height points in this thesis. While GPS has been used for deformation monitoring of engineering structures and to assist in damage assessment during and after extreme loading events, its use has been limited to roof top installations. This research is an attempt to measure displacements at mid-height locations of engineering structures of vertical profile using GPS. (For complete abstract open document).
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    Integration of vector datasets
    Hope, Susannah Jayne ( 2008)
    As the spatial information industry moves from an era of data collection to one of data maintenance, new integration methods to consolidate or to update datasets are required. These must reduce the discrepancies that are becoming increasingly apparent when spatial datasets are overlaid. It is essential that any such methods consider the quality characteristics of, firstly, the data being integrated and, secondly, the resultant data. This thesis develops techniques that give due consideration to data quality during the integration process.
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    Mapping riparian vegetation functions using remote sensing and terrain analysis
    LYMBURNER, LEO ( 2005)
    Land use practices over the last 200 years have dramatically altered the distribution and amount of riparian vegetation throughout many catchments in Australia. This has lead to a number of negative impacts including a decrease in water quality, an increase in sediment transport and a decrease in the quality of terrestrial and aquatic habitats. The task of restoring the functions of riparian zones is an enormous one and requires spatial and temporal prioritisation. An analysis of the existing and historical functions of riparian zones and their spatial distribution is a major aid to this process and will enable efficient use of remediation resources. The approach developed in this thesis combines remote sensing, field measurement and terrain analysis to describe the distribution of five riparian zone functions: sediment trapping, bank stabilization, denitrification, stream shading and large woody debris production throughout a large semi-arid catchment in central Queensland.
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    Improved processing models for network kinematic GPS positioning in sparse networks
    Grgich, Paul Mevko ( 2008)
    GPS positioning is a technique that has been growing in the quantity and variety of its use, particularly for applications that require high levels of accuracy. When high-accuracy positioning is undertaken, the atmospheric delays at the rover need to be accurately estimated. This enables the ambiguity fixing that in turn allows centimetre level positioning. In order to obtain the necessary accuracy in the atmospheric delays a relatively dense network of reference stations is required. The cost of installing and maintaining such a network is significant; and, in the case of sparsely populated areas, can be economically unviable. It would be desirable, therefore, to construct an alternative processing technique that is capable of achieving the necessary ambiguity fixing with a sparser reference network. Such an advance would not only reduce the cost of installing and maintaining reference networks, but would improve the performance of existing networks. Current techniques use a double differenced approach. This suffers from a variety of disadvantages which decrease the accuracy of the atmospheric delay estimates. This thesis proposes an undifferenced approach, which will not suffer from the same disadvantages. Such a methodology requires more rigorous a priori modelling, as no errors are cancelled out. Many effects that do not need to be estimated in double differenced processing, such as phase hardware delays, are crucial to the accurate estimation of atmospheric effects using the proposed technique.
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    Quantitative methods for hydrological spatial field comparison
    WEALANDS, STEPHEN RUSSELL ( 2006-08)
    This thesis addresses the current lack of comprehensive, quantitative methods for comparing hydrological spatial fields. Comparison of spatial fields is needed for assessing hydrological models and for data assimilation. The methods that are currently used for quantitative comparison generally fail to consider the spatial arrangement of element values within spatial fields. Instead, there is a dependence on qualitative methods (e.g. visual comparison) to undertake comparison of many aspects (e.g. intermediate scale features), but such methods are non-repeatable, often biased and difficult to report on. This thesis advances the comparison methods available for use with hydrological spatial fields. (For complete abstract open document)
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    A one-dimensional Boussinesq-type momentum model for steady rapidly varied open channel flows
    Zerihun, Yebegaeshet Tsegaye ( 2004-11)
    The depth-averaged Saint-Venant equations, which are used for most computational flow models, are adequate in simulating open channel flows with insignificant curvatures of streamlines. However, these equations are insufficient when applied to flow problems where the effects of non-hydrostatic pressure distribution are predominant. This study provides a comprehensive examination of the feasibility of a simple one-dimensional Boussinesq-type model equation for such types of flow problems. This equation, which allows for curvature of the free surface and a non-hydrostatic pressure distribution, is derived using the momentum principle together with the assumption of a constant centrifugal term at a vertical section. Besides, two Boussinesq-type model equations that incorporate different degrees of corrections for the effects of the curvature of the streamline are investigated in this work. One model, the weakly curved flow equation model, is the simplified version of the flow model based on a constant centrifugal term for flow situations that involve weak streamline curvature and slope, and the other, the Boussinesq-type momentum equation linear model is developed based on the assumption of a linear variation of centrifugal term with depth.
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    The significance of episodic recharge in the wheatbelt of Western Australia
    Lewis, Marjorie Fay ( 2000-11)
    Groundwater levels in the Wheatbelt of Western Australia are rising and causing severe and widespread land salinisation. Evidence from northern Victoria showed that episodic recharge pulses following floods had caused significant groundwater rises. The aim of this study was to determine: 1. whether episodic recharge was significant compared to regular recharge in the Wheatbelt; 2. the conditions under which episodic recharge occurs. (For complete abstract open document)