439 results for Doctoral, 2008

  • Analysis and Modelling of Probes in Waveguides and Mobile Radio Propagation and Systems Engineering

    Williamson, Allan (2008)

    Doctoral thesis
    The University of Auckland Library

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  • Novel Hybrid Materials And Their Applications

    Small, Aaron Charles (2008)

    Doctoral thesis
    Victoria University of Wellington

    The development of novel hybrid materials of cellulose fibres and substrates with nanoparticles, conducting polymers and quantum dots, opens up novel application for new packaging materials and paper based products for the ‘smart packaging’ and ‘functional products’ areas that are emerging in the paper and packaging industries. Examples of these materials which have been developed here include cellulose fibres and substrates functionalised with magnetic nanoparticles, electrically conducting polypyrrole, and photoluminescent zinc sulfide quantum dots. Such materials were synthesised and then characterised using Alternating Gradient Magnetometry (AGM), Atomic Absorption Spectroscopy (AA), Cotec Profilometer Measurements, DC Conductivity Measurements, Photoluminescence Spectroscopy (PL), Scanning Electron Microscopy (SEM), SQUID Magnetometry, Transmission Electron Microscopy (TEM), Vibrational Sample Magnetometry (VSM), X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and X-ray Photoelectron Spectroscopy (XPS). Ferrimagnetic magnetite nanoparticles (particle size 12-26 nm) were synthesised by a simple aqueous precipitation method and had a magnetic saturation of approximately 60 emu g⁻¹, a coercive field of approximately 12-120 Oe, and a remnant magnetisation of approximately 11 emu g⁻¹. Magnetite coated Kraft fibres (1.2 – 3.15 wt. % Fe) were synthesised by adding a colloidal suspension of magnetite nanoparticles to a suspension of Kraft fibres. The fibres retained their inherent properties, such as tensile strength and flexibility, but inherited the magnetic properties of the magnetic nanoparticles. The nanoparticles remained unchanged on bonding - presumably through hydrogen bonding between the surface hydroxyl groups of the cellulose and the oxygen present in the magnetite. Newsprint, Kraft Board and Cotton fabric were coated with polypyrrole using a chemical polymerisation method. SEM shows a complete coating, whereby the fibres are completely encapsulated by the polymer, including individual fibrils. Again, bonding is facilitated through hydrogen bonding between the surface hydroxyl groups of the cellulose and the lone pairs of the nitrogen in the polypyrrole backbone. Samples were doped with p-toluenesulfonic acid to increase conductivity, of which up to 4 S cm⁻¹ was achieved. The samples were coated with magnetite nanoparticles using a starch binder, and tested for their application in EMI shielding. A maximum shielding effectiveness of 43 % in the 1-18 GHz range and 47 % in the 16-40 GHz range was obtained using cotton fabrics coated with both polypyrrole and magnetite. A synergistic effect is observed on using a polypyrrole and magnetite coating. Photoluminescent ZnS quantum dots, synthesised using an aqueous precipitation method, were doped with Mn²⁺ and Cu²⁺ to achieve emissions at approximately 600 nm (Mn²⁺) and 530 nm (Cu²⁺) on irradiation with UV light. The quantum dots had a particle size of approximately 2 nm, and were present in the zinc blende phase. Doped ZnS-coated Kraft fibres (5 – 30 wt. % Zn) were synthesised by a number of methods, the most successful being the ‘in-situ’ method, in which a uniform and complete coating was afforded. The fibres retained their inherent properties, such as tensile strength and flexibility, but inherited the photoluminescent properties of the ZnS quantum dots. The quantum dots remained unchanged on bonding - presumably through hydrogen bonding between the surface hydroxyl groups of the cellulose and the sulfur present in the ZnS quantum dots. ZnS quantum dots doped with Mn² and Cu²⁺ were successfully formulated for inkjet printing by capping with mercaptosuccinic acid. Upon irradiation with UV light, emissions at approximately 600 nm (Mn²⁺-doped) and 530 nm (Cu²⁺-doped) were observed. These were successfully inkjet printed in intricate patterns onto a number of substrates, including photographic quality inkjet paper, cotton, and wool.

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  • Isolation of new secondary metabolites from New Zealand marine invertebrates.

    Wojnar, Joanna (2008)

    Doctoral thesis
    The University of Auckland Library

    This study describes the isolation and structure elucidation of several known and 13 new compounds from New Zealand marine organisms. Furthermore, it describes the development of a digital mask program for the analysis of HSQC spectra of crude sponge extracts. This was used as a screening tool to identify secondary metabolite producers that warranted further analysis. As reports of metabolites from New Zealand nudibranchs are poorly represented in the literature, a study of five New Zealand nudibranch species was undertaken. These coloured and seemingly undefended nudibranchs are known to concentrate or sequester toxic metabolites from their prey, facilitating rapid isolation and structure elucidation of these metabolites. This study resulted in the isolation of a variety of metabolite classes; two new compounds, 13alpha- acetoxypukalide diol (30) and lopholide diol (31) from the nudibranch Tritonia incerta, are described. Examination of the sponge Raspailia agminata resulted in the isolation of a novel family of partially acetylated glycolipids which contain up to six glucose residues. The chromatographic separation of these compounds was a challenge due to the similarity of the congeners and their lack of a chromophore. MSguided isolation eventually led to the purification of agminosides A-E (145-149). An unidentified sponge of the order Dictyoceratida was found to contain a new isomer (186) of the known sesterterpene variabilin. As variabilin-type compounds are predominantly found from sponges of the family Irciniidae, the unidentified sponge is most likely an irciniid. In addition, the sponge contained two prenylated quinones, one of which, 189, is a new isomer of a known sponge metabolite. The sponge Darwinella oxeata contained four new nitrogenous diterpenes of the aplysulphurane (rearranged spongian) skeleton, oxeatamide A (214), isooxeatamide A (215), oxeatamide A 23-methyl ester (216) and oxeatamide B (217).

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  • An instrumental case study of a professional development intervention that uses unfamiliar mathematics to prompt secondary teachers' re-thinking about learning and teaching.

    Paterson, Judith (2008)

    Doctoral thesis
    The University of Auckland Library

    This study is part of a professional development project working to enhance mathematics achievement and retention in schools in a low socio-economic region in Auckland, New Zealand. Over two years teachers of senior mathematics classes from ten schools attended workshops and meetings at which mathematicians and statisticians from the University of Auckland gave talks on aspects of their academic work. These talks form basis of the intervention that is the focus of this study. The aim of the study was to determine whether, when put in the position of encountering unfamiliar mathematics, teachers would re-view their understanding of learning, and what the results of this experience would be for their understanding of students learning needs and their teaching. In the workshops prompts and questions encouraged the teachers to discuss learning and teaching. It was hypothesised that this could lead to teachers becoming more open to considering change in their practice. A framework was developed in order to categorise the teacher talk that constituted the data. Measured against this framework the data showed that the intervention was effective in encouraging approximately 40% of the group of 31 teachers who attended one or more workshops to consider or enact change in their practice. The data was re-examined at a deeper level seeking to establish how and why the teachers responded as they did. On the basis of this a model of the processes and outcomes of teacher learning in the intervention was developed. This analysis showed that three strands of experience encouraged teachers to consider change in their practice: being re-energised for teaching through being mathematically stimulated; coming to realisations about teaching through introspection and identification with students as learners; and discussing teaching within a supportive learning community. A number of factors and contexts that impacted on teachers, responses to the intervention were identified.

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  • Prenatal and Postnatal Nutritional Influences on Neuroendocrine Expression and Susceptibility to Diet-induced Obesity.

    Ikenasio, Bettina (2008)

    Doctoral thesis
    The University of Auckland Library

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  • SAFDetection: Sensor Analysis based Fault Detection in Tightly-Coupled Multi-Robot Team Tasks

    Li, Xingyan (2008)

    Doctoral thesis
    The University of Auckland Library

    This dissertation addresses the problem of detecting faults based on sensor analysis for tightly-coupled multi-robot team tasks. The approach I developed is called SAFDetection, which stands for Sensor Analysis based Fault Detection, pronounced “Safe Detection”. When dealing with robot teams, it is challenging to detect all types of faults because of the complicated environment they operate in and the large spectrum of components used in the robot system. The SAFDetection approach provides a novel methodology for detecting robot faults in situations when motion models and models of multi-robot dynamic interactions are unavailable. The fundamental idea of SAFDetection is to build the robots’ normal behavior model based on the robots’ sensor data. This normal behavior model not only describes the motion pattern for the single robot, but also indicates the interaction among the robots in the same team. Inspired by data mining theory, it combines data clustering techniques with the generation of a probabilistic state transition diagram to model the normal operation of the multi-robot system. The contributions of the SAFDetection approach include: (1) providing a way for a robot system to automatically generate a normal behavior model with little prior knowledge; (2) enabling a robot system to detect physical, logic and interactive faults online; (3) providing a way to build a fault detection capability that is independent of the particular type of fault that occurs; and (4) providing a way for a robot team to generate a normal behavior model for the team based the individual robot’s normal behavior models. SAFDetection has two different versions of implementation on multi-robot teams: the centralized approach and the distributed approach; the preferred approach depends on the size of the robot team, the robot computational capability and the network environment. The SAFDetection approach has been successfully implemented and tested in three robot task scenarios: box pushing (with two robots) and follow-the-leader (implemented with twoand five-robot teams). These experiments have validated the SAFDetection approach and demonstrated its robustness, scalability, and applicability to a wide range of tightly-coupled multi-robot applications.

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  • Targeted delivery of polypeptides to antigen presenting cells by a modified bacterial superantigen

    McIntosh, Julie (2008)

    Doctoral thesis
    The University of Auckland Library

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  • Women’s Understandings of Sexuality, Sex and Sexual Problems: An Interview Study

    Bellamy, Gary (2008-10)

    Doctoral thesis
    The University of Auckland Library

    Background There are a paucity of studies that address women’s own understandings of sexuality and sexual problems. Much of the research and theory which underpin current diagnostic criteria for sexual problems is based upon a set of sexual norms which are predicated upon male experience. Moreover, these dominant understandings, entrenched in a perspective that favours the material body, fail to take account of contextual factors of women’s experiences. Objectives Within a diverse sample of women: to examine understandings of sexuality and sexual problems; explore the importance of sexual activity using their own definitions; and identify the influence of wider socio-cultural factors upon understandings of sexuality and sexual problems. Methods In-depth semi-structured interviews were conducted with thirteen women recruited from the general public and ten women recruited from a psychosexual clinic aged 23-72 years. Data analysis Data were analysed thematically using the conventions of template analysis within a material-discursive framework. Findings The findings of this study suggest that women’s understandings of sexuality, sex and sexual problems should be understood as bodily ‘experienced’ and socially and psychologically mediated. Participants also appear to be influenced by the relational context of their experience and draw upon a patriarchal explanatory framework to make sense of their own sexual functioning and satisfaction. Conclusions This study poses a challenge to the recent drive to medicalise women’s sexual problems via the Female Sexual Dysfunction (FSD) label. The findings dispute current diagnostic criteria for sexual problems which presuppose a highly individualized framework and take very little account of contextual factors. Consequently, this study concludes that such criteria need to consider biological, social, psychological as well as patriarchal and historical factors in determining the meaning and importance of sexuality, sex and sexual problems to women.

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  • Development and Characterization of Biomaterials for Fistula Repair

    Keshaw, Hussila (2008)

    Doctoral thesis
    The University of Auckland Library

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  • A Wideband Feed for a Cylindrical Radio Telescope

    Leung, Martin (2008)

    Doctoral thesis
    The University of Auckland Library

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  • Metal complexes of phosphinite ligands as catalysts for asymmetric hydrogenation reactions

    Slade, Angela (2008)

    Doctoral thesis
    The University of Auckland Library

    The objective of this thesis is two-fold. First to ascertain how phosphinite compounds behave when reacted with transition metal substrates. The second objective is to establish whether the resulting complexes were asymmetric catalysts for conversion of prochiral substrates to chiral products in high ee.

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  • Targeted delivery of polypeptides to antigen presenting cells by a modified bacterial superantigen

    McIntosh, JD (2008)

    Doctoral thesis
    The University of Auckland Library

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  • The Value of a Hapū Perspective to Municipal Water Management Practice: Mauri and potential contribution to Sustainability Decision Making in Aotearoa New Zealand

    Morgan, Te Kipa (2008)

    Doctoral thesis
    The University of Auckland Library

    The Mauri Model is a decision making framework that integrates the social, economic, environmental, and cultural well-being dimensions of sustainability assessment. The Mauri Model is a new decision making framework that adopts mauri ('integrity' or the binding force between the physical and the spiritual elements) as the measure of environmental, economic, social, and cultural well-being in place of the monetary basis used conventionally for sustainability assessment. The Mauri Model has the potential to improve the cross-cultural understanding of practitioners with respect to sustainability, and empower Indigenous people's voices within decision making processes. Mauri is the bonding force between the spiritual and the physical. When this bond is extinguished the result is death in a living organism or alternatively the loss of capacity to support life in a material such as air, water or soil. The decision making framework incorporates this concept into a series of steps to determine whether the mauri of each dimension is being fully restored, enhanced, maintained, diminished, or totally destroyed. The use of mauri rather then money as the measure of sustainability avoids the disadvantage of making decisions based solely on economic or psuedo-economic considerations. The Mauri Model has been trialed in a range of workshops since 2003, including SmartGrowth BOP, House of Tahu, and Mauri Tu Mauri Ora. The primary application of the Mauri Model is in planning and engineering sustainability, although ultimately the focus is well-being and therefore the model has very broad appeal to other professions including health and law.

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  • Robust control for uncertain networked control systems with random delays

    Huang, Dan, 1980- (2008)

    Doctoral thesis
    The University of Auckland Library

    Networked control systems (NCSs) are a type of distributed control systems where sensors, actuators, and controllers are interconnected through a communication network. This system setup has the advantage of low cost, °exibility, and less wiring, but it also inevitably invites some delays and data loss into the design procedure. The focus of this thesis is to address the problem of analysis and design of networked control systems when the communication delays are varying in a random fashion. This random feature of the time delays is typical for commercially used networks, such as a DeviceNet (which is a controller area network (CAN)) and Ethernet network. Models for communication network delays are ¯rst developed, in which Markov processes are used to model these random network-induced delays. Based on such models, we establish novel methodologies for stability analysis, control with disturbance attenuation, and fault estimation for a class of uncertain linear/nonlinear uncertain NCSs with random communication network-induced delays in both sensor-to-controller and controller-to- actuator channels. Data packet dropouts in the communication channels also have been taken into consideration in the modelling and design procedure. The main technique used in this thesis is based on the Lyapunov-Razumikhin method, which results in delay-dependent controllers. We ¯rst consider the design prob- lems for uncertain linear NCSs. In this case, state feedback controllers and dynamic output feedback controllers are designed to satisfy both stability and disturbance at- tenuation requirements for this class of NCSs. Moreover, a robust fault estimator that ensures the fault estimation error is less than a prescribed performance level is designed. We further go on to address the control problems for uncertain nonlinear NCSs. The nonlinear plant is ¯rst described by the T-S fuzzy model. Based on this model, stability analysis, disturbance attenuation, and fault estimation problems are studied for uncer- tain nonlinear NCSs. It should be noted that system uncertainties, disturbances and noises are addressed in both cases. The existence of such controllers and fault estimators are given in terms of the solvability of bilinear matrix inequalities. Iterative algorithms are proposed to change this non-convex problem into quasi-convex optimization problems, which can be solved e®ectively by available mathematical tools. Finally, to demonstrate the e®ectiveness and advantages of the proposed design methodologies in this thesis, numerical examples are given in each designed control systems. The simulation results show that the proposed design methodologies can achieve the prescribed performance requirements.

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  • Interpreting references to the subject in philosophical writings

    Nickless, David, M.A. (2008)

    Doctoral thesis
    The University of Auckland Library

    In this thesis I will develop and test an interpretive framework for the Subject based on the understanding that an entity can be identified as a Subject if it is the necessary referent for an attribution. This understanding provides a template for approaching different Subjects, for considering the validity of their being identified as Subjects, and for reorienting the general discourse of the Subject away from an investigation of particular entities to one concerned with the contexts which support such identifications.

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  • Aspects of adolescent obesity in New Zealand: quality of life, psychosocial factors and psychological theory

    Carne, Sarah S. (2008)

    Doctoral thesis
    The University of Auckland Library

    Purpose: To ascertain the quality of life (QOL) in an adolescent population with a high prevalence of obesity, compare findings to previous research, and investigate psychosocial factors that may account for differences in results by use of psychological theory. Rationale: A landmark article by Schwimmer et al. (2003) found that the QOL of severely obese children and adolescents was similar to those who had been diagnosed with cancer. It was therefore timely to discover whether a population with a high prevalence of obesity would also experience low QOL, or whether this population would normalise a higher weight status, resulting in less stigma and higher QOL. Understanding the results in terms of psychosocial factors and psychological theory will assist in more appropriate targeting of interventions.

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  • Induction experts: An analysis of beginning teacher support in low-socioeconomic New Zealand primary schools

    Main, Andrea Squirrel (2008)

    Doctoral thesis
    The University of Auckland Library

    This thesis analyses induction programmes in low-socioeconomic New Zealand primary schools. A review of the literature indicates that effective induction is integrated and has four main components: pedagogical development, socioemotional support, professional agency, and structured balance. In addition, New Zealand’s induction programmes are reported to be strong by international standards. Literature is synthesised to create a framework of low-socioeconomic schools as induction experts. Although there have been large-scale analyses of New Zealand induction programmes, there has been no research on the integrated induction systems found in low-socioeconomic primary schools. A mixed-methods approach was used to investigate the support provided for beginning teachers (BTs) in these schools. Methods included a nationwide survey of BTs in low-socioeconomic primary schools, which was mailed to 467 primary and intermediate BTs (44% response rate). Additionally, from all 156 low-socioeconomic primary schools, five exemplar induction programmes were selected and visited throughout the 2007 school year. Survey analysis, success case methods, discourse analysis, and grounded theory methods indicated that induction in these schools is integrated and strong by international standards. Findings indicate that induction programmes in low-socioeconomic schools are pedagogical, supportive, and well structured; however, not all schools focus on enhancing the professional agency of teachers. Exemplar practices such as peer coaching, university partnerships, on-site BT support groups, curricular leadership roles, and formal programme evaluations were found at case study sites. Analyses of factor themes, cluster graphs, frequency-utility matrices, documents, events, and transcripts of meetings and interviews reveal several key findings. First, the Hauora model—a Mäori concept of balanced pedagogical, spiritual, socioemotional, and physical development—may be applicable to induction in the New Zealand setting. Second, analyses indicate that low-socioeconomic schools have relatively strong induction programmes. Third, some teachers—particularly those beginning after the start of the school year or older teachers in their second year of teaching—may receive varied support. Findings from this research may provide framing for induction programmes in New Zealand as well as for international longitudinal studies of teacher induction models.

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  • Topics on Structural Transformation and Economic Development

    Bah, El-Hadj (2008)

    Doctoral thesis
    The University of Auckland Library

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  • Supporting the emergence of a shared services organisation: Managing change in complex health ICT projects

    Day, Karen Jean (2008)

    Doctoral thesis
    The University of Auckland Library

    Although there is a high risk of failure in the implementation of ICT projects (which appears to extend to health ICT projects), we continue to implement health information systems in order to deliver quality, cost-effective healthcare. The purpose of the research was to participate in and study the change management as a critical success factor in health ICT projects, and to examine people’s responses to change so as to develop understanding and theory that could be used in future change management programmes. The research was conducted within the context of a large infrastructure project that resulted from the emergence of a shared services organisation (from two participating District Health Boards in Auckland, New Zealand). Action research (AR) formed the basis of the methodology used, and provided the foundation for a change management programme: the AR intervention. Grounded theory (GT) was used for some of the data analysis, the generation of themes by means of constant comparison and the deeper examination of the change process using theoretical sampling. AR and GT together supported the development of theory regarding the change process associated with health ICT projects. Health ICT projects were revealed in the findings as exhibiting the properties of complex adaptive systems. This complexity highlighted the art of change management as a critical success factor for such projects. The fabric of change emerged as a composite of processes linked to project processes and organisational processes. The turning point in the change process from the before state to the after state is marked by a capability crisis which requires effective patterns of leadership, sensitive targeting of communication, effective learning, and management of increased workload and diminishing resources during the course of health ICT projects. A well managed capability crisis period as a component of change management can substantially contribute to health ICT project success.

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  • Microarray-based gene set analysis in cancer studies

    Song, Qin Sarah (2008)

    Doctoral thesis
    The University of Auckland Library

    This work addresses the development and application of gene set analysis methods to problems in microarray-based data sets. The work consists of three parts. In the first part a gene set analysis method (PCOT2) is developed. It utilizes inter-gene correlation to detect significant alteration in gene sets across experimental conditions. The second part is focused on the exploration of correlation-based gene sets in conjunction with the application of the PCOT2 testing method in the investigation of biological mechanisms underlying breast cancer recurrence. In the third part, statistical models for analyzing combined microarray-based expression and genomic copy number data are developed. In addition, an analysis which incorporates tumour subgroups is shown to provide more accurate prognosis assessment for breast cancer patients.

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