13,067 results for Doctoral

  • Discovery of novel circular replication-associated protein encoding single-stranded DNA viruses in ecosystems using viral metagenomic approaches

    Dayaram, Anisha (2015)

    Doctoral thesis
    University of Canterbury Library

    The introduction of next-generation sequencing (NGS) technologies has dramatically changed the field of virology, with many significant discoveries of novel circular replication-associated protein (Rep) encoding single-stranded (CRESS) DNA viruses. Traditionally, most research into CRESS DNA viruses has often focused on investigating plant and animal pathogens that are of significant economic importance. This research has led to the discovery and establishment of three different CRESS DNA families including Geminiviridae, Nanoviridae and Circoviridae, which infect eukaryotes. CRESS DNA viruses can have single or multicomponent genomes, with the latter requiring all components for infection. CRESS DNA viruses have circular single-stranded DNA (ssDNA) genomes with at least one protein encoding a Rep which is responsible for viral replication. It has been shown that CRESS DNA viruses are able to evolve rapidly with nucleotide substitution rates that are similar to those observed in RNA viruses. The Rep gene has conserved regions known as motifs which are often used to determine relatedness between CRESS DNA virus. NGS has expanded our knowledge on the diversity of novel CRESS DNA viruses. Viral genomes are now routinely recovered from different sample types without any prior knowledge of the viral sequence. This has led to the development of the field of viral ecology. This field places an emphasis on viruses being one of the most abundant organisms on earth, and are therefore likely to play a major role in ecosystems. Environmental metagenomic studies have isolated CRESS DNA viruses from sea water, freshwater, faecal matter from various animals, soil, the atmosphere, sediments and sewage; dramatically increasing the known CRESS DNA viral genomes in the public domain. These studies are shedding light on the distribution of CRESS DNA viruses, as well as providing baseline data for future studies to examine virus-host interactions, community structure and ultimately viral evolution. Vector enable metagenomics (VEM) is another novel approach utilising NGS techniques for discovering CRESS DNA viruses. As many plant-infecting CRESS DNA viruses such as geminiviruses and nanoviruses are vectored by insects, this approach exploits this mechanism by using insect vectors as a surveillance tool to monitor and survey these viruses circulating in ecosystems. Recent studies have used these methods to identify known viral plant pathogens as well as novel viruses circulating in insect vectors such as whiteflies and other higher order insects such a mosquitoes and dragonflies. These approaches successfully demonstrated that VEM can be used as a unique method, with the first mastrevirus discovered in the new world being recovered from dragonfly species Erythrodiplax fusca using this approach. The research in this thesis uses metagenomics to survey CRESS DNA viral diversity in different organisms and environments. Two hundred and sixty eight novel CRESS DNA viruses were recovered and verified in this study from a range of sample types (adult Odonata, Odonata larvae, Mollusca, benthic sediment, water, Oligochaeta and Chironomidae) collected in the United States of America, Australia and New Zealand. All viral genomes isolated had two major proteins encoding for a putative Rep and coat protein (CP), with major Rep motifs identified in most Reps. Phylogenetic analysis of the Reps encoded by the viral genomes highlighted that most were extremely diverse falling outside of the previously described ssDNA viral families. A top-down approach was implemented to recover CRESS DNA viruses and possible viral pathogens from Odonata and their larvae. Thirty six viral genomes were recovered from terrestrial adult dragonflies as well as the twenty four from aquatic larvae. Dragonfly cycloviruses were isolated from the some adult Odonata species which were closely related to the isolates previously described by Rosario et al. (2012). The viruses isolated in the aquatic and terrestrial ecosystems differed substantially indicating that different CRESS DNA viromes exist in both land and water. The diversity of CRESS DNA viruses in seven different mollusc species (Amphibola crenata, Austrolvenus stutchburyi, Paphies subtriangulata, Musculium novazelandiae, Potamopyrgus antipodarum, Physella acuta and Echyridella menziesi) from Lake Sarah and the Avon-Heathcote estuary both in New Zealand, were also investigated. One hundred and forty nine novel viral genomes were recovered. Two CRESS DNA genomes were recovered from molluscs which have Rep-like sequences most closely related to those found in some bacterial genomes. Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1) was originally isolated from fungal species Sclerotinia sclerotiorum in china and was later found in benthic sediments in New Zealand. As part of this study, SsHADV-1 was recovered from dragonflies (Erythemis simplicicollis, Ischnura ramburii and Pantala hymenaea) collected in Arizona and Oklahoma, USA suggesting a larger distribution of these viruses and not surprising given the near global distribution of S. sclerotiorum. Dragonfly larvae-associated circular DNA viruses (DflaCVs) that were originally isolated in Odonata larvae samples from three New Zealand lakes were later recovered from water, benthic sediment, worms and molluscs from one of the lakes initially sampled, suggesting that these viruses are ubiquitous in freshwater environments. This study has attempted to generate baseline data of CRESS DNA viruses in certain environments using NGS-informed approaches. This data was used to try and establish whether viral distribution in different samples types can potentially be explained by the food web interactions between different samples types. Although the analysis did not show any significant relationships between sample type interactions and viral distribution a few common associations between Odonata larvae and benthic sediment were evident. This was expected as the larvae live within the sediment so it could be assumed that they potentially have similar CRESS DNA viral distribution. Although the distribution of viruses varied across sample types, molluscs proved the best sampling tool for isolating largest numbers of CRESS DNA viruses in an ecosystem with extensive diversity. Overall, this research demonstrates the applications of NGS for investigating the diversity of CRESS DNA viruses. It demonstrates that some sample types such as Odonata in terrestrial systems and molluscs in aquatic environments, can be used as effective sampling tool to determine the diversity of CRESS DNA viruses in different environments as well as detecting previously isolated viruses. The CRESS DNA viruses isolated in this body of work provides baseline data that can potentially be used in future research to investigate hosts of these viruses and their interactions with hosts and potential flow in their environments.

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  • Contextual factors affecting the development of digital library education in Vietnam

    Do, Van Hung (2015)

    Doctoral thesis
    Victoria University of Wellington

    In Vietnam the need for digital library education (DLE) has increased significantly in the last two decades. Educating staff to establish and manage digital libraries has become a critical issue. However, there are no DLE programmes offered by library and information management (LIM) education providers in Vietnam and we do not know why this is the case. The aim of this study is to investigate and understand the factors affecting the development of DLE for LIM practitioners in Vietnam. The interpretive study employed a qualitative approach and its findings are based on the analysis of data gathered in 17 individual interviews and 11 focus groups with key stakeholders, as well as from documentary evidence. The stakeholders involved in this study include LIM practitioners, LIM managers, LIM lecturers, library school deans, government policy makers, academic library directors, professional association chairpersons and LIM students. To guide the data gathering and analysis, an initial conceptual model of factors affecting DLE was developed from three sources: Fullan’s Educational Change theory, Nowlen’s Performance Model in continuing education for practitioners, and Rogers’s Diffusion of Innovations theory. The study found seven major factors were affecting the development of DLE in Vietnam: the government, the information technology infrastructure, the prevailing social and cultural values, the efforts of change agents, the attitudes of key stakeholders, the characteristics of DLE design, and the nexus of the educational needs of library staff and the libraries in which they were working. Of these the government factor was the most influential. These factors were inter-related and affected DLE development at different levels. The initial conceptual model was revised based on the study's findings. The revised model provides a contribution to educational change theories relevant to the identification and understanding of factors affecting professional educational programmes in universities in developing countries. The study’s findings are also of value to governments, libraries, library schools and library associations for developing relevant policies and new curricula for DLE, and for establishing new professional development programmes in DLE for library staff.

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  • Supporting the use of algorithmic design in architecture: An empirical study of reuse of design knowledge

    Globa, Anastasia (2015)

    Doctoral thesis
    Victoria University of Wellington

    This thesis tests the reuse of design knowledge as a method to support learning and use of algorithmic design in architecture. The use of algorithmic design systems and programming environments offer architects immense opportunities, providing a powerful means to create geometries and allowing dynamic design exploration, but it can also impose substantial challenges. Architects often struggle with adopting algorithmic design methods (translating a design idea into an algorithm of actions), as well as with the implementation of programming languages, the latter often proving frustrating and creating barriers for both novice and advanced software users. The proposition explored in this thesis is that the reuse of design knowledge can improve architects’ ability to use algorithmic design systems, and reduce the barriers for using programming. This study explores and compares two approaches as a means of accessing and reusing existing design solutions. The first approach is the reuse of abstract algorithmic ‘Design Patterns’. The second is the reuse of algorithmic solutions from specific design cases (Case-Based Design). The research was set up as an experimental comparative study between three test groups: one group using Design Patterns, a second group using Case-Based Design, and the control group. A total of 126 designers participated in the study providing sufficient numbers within each group to permit rigorous studies of the statistical significance of the observed differences. Results of this study illustrate that the systematic inclusion of the Design Patterns approach to the learning strategy of programming in architecture and design, proves to be highly beneficial. The use of abstract solutions improves designers’ ability to overcome programming barriers, and helps architects to adopt algorithmic design methods. The use of Design Patterns also encourages design exploration and experimentation. The use of the Case-Based Design approach seems to be more effective after designers and architects, who are novices in programming, gain more experience with the tool. It encourages more focused reasoning, oriented to the realisation of a particular (originally intended) design outcome. The contribution of this research is to provide empirical evidence that the reuse of abstract and case-based algorithmic solutions can be very beneficial. Results of this study illustrate that both reuse methods can be strategically integrated into design education and architectural practice, supporting learning and use of algorithmic design systems in architecture. The study also identifies potential weaknesses of each approach, proposing areas which could be addressed by future studies.

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  • Public Streets for Multicultural Use: Exploring the Relationship between Cultural Background, Built Environment, and Social Behaviour

    Lesan, Maryam (2015)

    Doctoral thesis
    Victoria University of Wellington

    Public space is the domain of interest for urban planners and designers and the most important type of public space is streets. Public spaces, and particularly busy streets in urban centres, provide opportunities for people to meet, often by chance. As cities become increasingly multi-cultural in population the use and nature of public space reflects this. The best public spaces cater to the needs of all who use them and in multicultural societies this also means they must meet the expectations of people from different cultures. Many scholars have challenged the tendency for streets to be conceived of as movement channels, often at the expense of their use as social space. Streets have traditionally catered to a broad array of activities including walking, cycling and standing. Streets that facilitate such activities are preferred by the public. Streets in multicultural societies are also where people from different ethnic backgrounds find opportunities to interact. When public spaces are successful, they will increase opportunities to participate in communal activities. Spatial design is a critical success factor for streets; a goal for urban designers must be to create spaces where people from different social and cultural backgrounds value the public spaces they have access to. As cities become more multicultural the challenge is to design and manage spaces that appeal to the breadth of cultures that are represented in the population. Such public spaces are described in the literature as being more public. However, there is presently little information to help planners and designers to realise streets that appeal to people having different socio-cultural backgrounds. The research aims to identify those characteristics that will promote and maintain cultural diversity in the context of neighbourhood commercial streets in New Zealand’s multi-cultural society. The research is undertaken in two stages. “Stage One” makes use of ethnographic fieldwork as a basic method, complimented by structured field observations using a behavioural mapping procedure, and surveys of users of the streets. This stage provides data on specific streets and their usage through three case studies. Stage Two” utilises online surveys that generated data in relation to street visualizations. This stage seeks to understand what design characteristics and furniture arrangements are associated with stationary, social and gathering activities of people and to define design characteristics of footpath spaces preferred by each cultural group and all groups collectively. The main conclusion from this research is that retail activities remain the main concern of people in multi-cultural streets. Management and higher level planning of retail activities on the streets could encourage and motivate possible tenants in order to enrich the retail assortment of the street and provide a means for social and cultural diversity. In addition to business activities, spatial design characteristics are found to have an influence on people’s behaviour and activity. The findings of this research suggest that retail and business activities, together with the design and skilful management of the public areas, could support a broader range of static and social activities among people of various cultural backgrounds. The thesis makes recommendations for urban planners and designers based on the findings of the research.

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  • La Représentation du local, de l’universel et de la réalité dans Rue la Poudrière, Le Voile de Draupadi et Le Sari vert d’Ananda Devi

    Dausoa, Mukta (2015)

    Doctoral thesis
    Victoria University of Wellington

    This doctoral thesis, written in French and entitled « La Représentation du local, de l’universel et de la réalité dans Rue la Poudrière, Le Voile de Draupadi et Le Sari vert d’Ananda Devi », is an in-depth historico-sociological analysis of Mauritian writer Ananda Devi’s three novels published in 1988, 1993 and 2009 respectively. Having Mauritius as their background, these three novels introduce themes such as slavery, the trans-oceanic experience of Indian indentured labourers, prostitution, rape, domestic violence and homicide, through female protagonists in Rue la Poudrière and Le Voile de Draupadi, and a male protagonist in Le Sari vert. Existing research on Devi’s work concentrates mostly on the plight of women, who are victims of a Mauritian patriarchal society. Moving away from this approach, my research focuses on the spatial, historical and sociological dimensions in order to closely analyse the surroundings of the characters. The first focus of this research is to see whether these three novels exclusively allude to Mauritian society or also deal with universal concepts. The second focus is to determine the degree of realism of these three fictional works. Thus, the overall focus of this research is to scrutinise the degree of particularism, universalisation and realism in the geographical, historical and social dimensions of the novels. I begin with a brief presentation of Ananda Devi and her place in Mauritian literature. Then, I explain the objectives of the thesis and introduce my methodologies, which include the theories of Tzvetan Todorov and Jean-Marc Moura used to analyse the local and universal aspects, and the theories of Guy de Maupassant, Roland Barthes, Maureen Ramsden, Vincent Jouve, Michael Riffaterre, Mark Sainsbury, Névine El Nossery used to frame the examination of realism. Sociological theories of Emile Durkheim and Robert Merton are also elaborated, to support the analysis of the social dimension. In order to better scrutinise the historical dimension of the novels, I have used the work of Mauritian and international historians as well as Mauritian and international governmental reports. Khal Torabully’s notion of coolitude is also discussed to evaluate how different ethnic groups are represented in the novels. I have in addition coined the term “le rêve mauricien”, in relation to the social dimension of the novels. Finally, I conclude with issues of realism, the local, the universal and fiction.

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  • Veitalatala: Mātanga ‘o e Talanoa

    Toluta'u, Talita Kiume

    Doctoral thesis
    Auckland University of Technology

    This study is concerned with representation. It considers the nature of a culturally located, discursive form called veitalatala and its creative translation into designed artifacts that consider the lyrical and graceful nature of Tongan women’s talanoa. The designed outcomes of the project consider the memories of three hou’eiki fafine (Tongan women) who left their homeland to settle abroad. Veitalatala: Mātanga ‘o e Talanoa is a creative synthesis of their talanoa, into new forms of artistic narrative, designed to capture the cultural and emotional resonance of their identities. The lyrical works orchestrate photography, animation, musical composition, sound design, filmed interviews, graphic design, sublimation printing on ngatu, and extensive postproduction experimentation, into unique texts that move the parameters of traditional documentation beyond conventional audio/visual interview. In so doing, the ngatu portraits and filmic veitalatala conceptually, contribute to the Tongan concept of luva (giving). Although Churchward (1959) defines veitalatala as a distinctly poetic form of talanoa, recent interviews with Havea (2014), Puloka (2014), Taliai (2014), Manu’atu, (2014), Taufa (2014), and Taumoepeau (2014) suggest that veitalatala is a complex and nuanced form of communication with diverse origins. Significantly, Tongia (2014) associates the term veitalatala with hou’eiki fafine. He suggests that it is a harmonious form of communication historically and socially related to the female gender. This thesis proposes through practice, that the tenets of veitalatala may be extended into artistic artifacts to create a contemporary, lyrical, yet culturally consistent means of representing histories and memories of Tongan hou’eiki fafine.

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  • Factors influencing the airport customer experience: a case study of Auckland International Airport's customers

    Losekoot, Erwin

    Doctoral thesis
    Auckland University of Technology

    The aim of this study was to investigate the factors influencing the airport customer experience. Much current research and management effort on airports focuses on efficiency, effectiveness, speed of processing and rankings on international league tables. These measures seem to reward those airports which can best move the largest number of passengers and their luggage. The writer of this study believed that the ‘experience’ of the ‘airport customer’ (passengers and those meeting or farewelling them) is not being given sufficient prominence at a time when it is recognised that the ‘experience economy’ can add value and create customer loyalty. New Zealand’s largest airport was the case study location for this research, and 120 interviews were undertaken in the airport environment with people who were experiencing the airport, either as arriving or departing passengers, or those greeting or farewelling them. In addition, 10 interviews were undertaken with airport management to explore their perceptions of the airport customer experience. All interviews with airport customers were undertaken in the land-side food court area of the international terminal. A plan of the airport is provided in Appendix 2 to assist the reader in understanding the layout of the airport. The guided conversations were focused on encouraging participants to share their perspective of the airport customer experience in order to build on what is already known from the quantitative surveys of passengers which are the more common form of research into airports. Together with the above data, the writer also kept a detailed research diary with observations made over the course of the data gathering phase. Hermeneutics guided the interpretive process which resulted in a number of overarching themes or notions which form the basis of this study’s findings. These include processes, people, physical environment and ‘placeness’. However, the research also uncovered what the writer has termed a ‘personal travel philosophy’. There was a significant number of people who, despite delays and other obstacles to their travel plans, appeared to be remarkably content with their lot at the airport, and this term is used to describe that group. The research concludes with a proposed model of the airport customer experience addressing five aspects – physical environment, processing, people, placeness and personal travel philosophy – and provides recommendations for airport management and opportunities for further academic research both in airports and in congruous areas such as hospitals. Airport management must spend time making people feel welcome if these spaces are to be perceived as hospitable places. The contribution that this thesis makes to the body of knowledge is a deeper understanding of the factors influencing the airport customer experience in the customers’ own words. It allows the voices of airport customers to be heard in a way that has not previously happened, in part because the dominant paradigm is a positivist one of facts, figures, benchmarks and league tables. By taking the time to listen carefully in an open-ended discussion, this research has identified much of what the airport customer really feels about the space they are obliged to spend an increasing amount of time in.

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  • Values in Antarctica: Discourse Analyses of Two Topical Issues in Antarctic Policy

    Engelbertz, Sira (2015)

    Doctoral thesis
    University of Canterbury Library

    In light of growing international awareness and interests in the ‘frozen continent’ of Antarctica, the topic of Values in Antarctica has recently gained more research interest. Due to the complexity of the concept of value, values in Antarctica have been approached from many different perspectives, including Antarctic wilderness and aesthetic values, values manifested in Antarctic law or value based behavioural changes through the Antarctic experience. The present thesis addresses values as human connections to Antarctica with a focus on Antarctic policy-making. The investigation contained three analytical stages that built on each other. The first stage has been an interdisciplinary literature review examining what values are and how values can be studied, but also considered values in the context of environment, human behaviour and policy. Value and value-related concepts were selected in view of a potential application to the Antarctic. The second analytical stage involved a general framework analysis of the Antarctic Treaty System to identify key elements and structures in the system suitable for a study of Antarctic values, and to develop the research questions. The third stage of analysis included empirical investigations of two Antarctic case studies. Key elements that influence the Antarctic Treaty System in a way that is relevant for a study of Antarctic values include external factors and events, action situations and actors participating in these action situations. Antarctic Treaty Meeting of Experts appeared as an action situation particularly suitable for a study of Antarctic values. The last two Antarctic Treaty Meeting of Experts on ship-borne tourism and climate change have been chosen as case studies, presenting two topical issues in Antarctic policy. Using discourse analysis based on documents submitted to the meetings and the meetings’ reports, values that are driving the discourses were to be identified through structures and patterns in the discourses. Further, based on the discourse analysis following three research questions were to be answered: What role is ascribed to Antarctica concerning contemporary issues? Where and why do conflicts arise in the ATS policy-making process that are based on conflicting values? What changes in the underlying belief-systems are driving policy-making processes and what has caused the change? Based on the literature, values are defined as internalised codes that affect behaviour and include judgements on what is good and desirable. Through the framework analysis it was identified that Antarctic policy involves a multi-layered system of different value systems, which was considered in the two case studies. For both case studies, values in the discourses were mostly identified based on Schwartz’s basic human value theory. The most prominent human value that drives both the ship-born tourism and the climate change discourse is security. Both discourses are further motivated by the conservation of the Antarctic environment and its associated ecosystems. Other values, such as power and conformity with rules were also clearly expressed in the discourses. With regard to the research questions, both case studies discussed Antarctica from two different perspectives, as a hazardous place for human activities and as a place vulnerable to any kind of changes. Conflicts in the ship-borne tourism discourse were more obvious, while the climate change discourse within the expert meeting proceeded in consensus. Value-based changes that are evident in changes in belief-systems underlying Antarctic policy-making could not be identified. This thesis argues, based on careful consideration of documents, that values play a crucial role in Antarctic policy-making at a number of different scales: individuals, political actors, and governmental levels. Values were found to be at the core of most, if not all, conflicts within the Antarctic system. Finally, this thesis provides the first understanding of the values held by the various stakeholders involved in governing and use of the Antarctic, which is crucial for further decision-making and research.

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  • Evolution Of The Unnecessary : Investigating How fMet Became Central In Bacterial Translation Initiation

    Catchpole, Ryan Joseph (2015)

    Doctoral thesis
    University of Canterbury Library

    All bacteria initiate translation using formylated methionine, yet directly after translation, the formyl-group is removed. This sequence of addition and removal appears futile, yet every sequenced bacterial genome encodes the enzymes for formylation and deformylation, suggesting this process is essential. Puzzlingly, the process is absent from both Archaea and Eukaryotes, and moreover, bacterial mutants lacking both the formylase and deformylase activities are viable, albeit with a diminished growth rate. We created an Escherichia coli strain devoid of formylase and deformylase activity. This strain was then allowed to evolve over 1500 generations whereupon it reached wild-type growth rate, demonstrating that formylation can be completely dispensed with. This raises an additional question: if the formylation cycle is unnecessary, how did it emerge and why has it persisted? Our results show that the formylation-deformylation cycle could have evolved as a toxin-antitoxin pair (TA) with post-segregational killing (PSK) activity. TAs ‘addict’ cells to the plasmids that carry them by inducing PSK. We measured the stability of formylase-deformylase encoding plasmids and their ability to elicit PSK in our evolved E. coli strain. We report several lines of evidence consistent with the formylation-cycle having evolved from a plasmid-borne PSK element: 1) in the absence of deformylation, formyl-methionine on proteins is cytotoxic in bacteria 2) deformylation relieves the cytotoxicity of formyl-methionine, 3) the loss of a plasmid containing formylase and deformylase genes from evolved cells results in cessation of growth – a standard PSK phenotype. In addition, we introduced the E. coli formylase and deformylase genes into yeast and demonstrate that Met-tRNA formylation is not lethal, even in the absence of deformylation. This suggests PSK would be ineffectual in yeast, accounting for the absence of formylation from eukaryotic cytoplasmic translation. We also report the presence of formylase and deformylase genes in the two representative members of the archaeal Methanocopusculum genus. Moreover, we demonstrate that these genes have been acquired by a recent horizontal gene transfer from bacteria. Our results indicate that formylmethionine use in bacteria evolved, not through a direct functional benefit to cells, but through competition between infectious genetic elements.

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  • Luck egalitarianism and educational equality.

    Calvert, John Sinclair (2014)

    Doctoral thesis
    University of Canterbury Library

    This thesis investigates whether luck egalitarianism can provide a cogent and coherent interpretation of educational equality. Historically, the belief that each child should receive an equally good education has exerted a strong influence on policy makers and thus on educational practice, and this despite the vagueness of the egalitarian formula. More recently however, the ideal has been undermined in practice by the rise of neoliberalism and in theory by a number of thinkers advocating other principles of educational justice. But it is vital to be clear about what each child is owed because of the profound effects of education on a person’s life prospects. The motivation for this work is therefore to determine whether educational equality can be rescued as a desirable and animating ideal of educational justice. In order to achieve this, I examine luck egalitarianism, a theory of distributive justice that has its origins in the work of John Rawls, but is now the major rival to his account of egalitarian justice. I probe at the fundamental moral intuitions underpinning luck egalitarianism and how it brings together the morally potent ideas of equality, luck and choice. I argue that these are of relevance for the education each child is owed and I propose a luck egalitarian conception of educational equality, argue that it is a cogent interpretation of egalitarian justice, and conclude that a luck egalitarian conception shows educational equality to be an ideal that is relevant, coherent and what morally matters most for justice in education. I describe luck egalitarianism as resting on three basic moral beliefs: that distributive equality is a fundamental demand of justice; that luck undermines fair equality; and that a person’s genuine choices can sometimes, under certain background conditions, render some otherwise objectionable inequalities not unjust. I then examine whether these three beliefs are compatible with each other and what, if anything, links them. Next, I consider luck egalitarianism’s status as a theory of distributive justice and argue that far from this being a weakness, as Elizabeth Anderson (1999) has notably argued, it is a strength of the position. But to appreciate this it needs to be seen that luck egalitarianism makes no claim to being all of justice and that the equalisandum of equality is complex and egalitarianism is intrinsically pluralist in nature (with a particular understanding of what is meant by pluralist). I consider too whether it is a mistake to say that inequalities that are largely due to luck can really be thought of as unjust. Thomas Nagel (1997) has argued that it is merely misfortune, unless the result of deliberate actions or social structures for which someone is responsible. I reject that position and argue that no one has to be responsible for an inequality for it to be unjust. Having interrogated luck egalitarianism and found it to be a sound account of egalitarian distributive justice, I turn to looking at whether it can illuminate our understanding of educational equality. Educational equality is often interpreted in terms of equality of educational opportunity. I look particularly at a conception of equality of educational opportunity, strongly influenced by Rawls, that has been thoughtfully and carefully articulated by Harry Brighouse and Adam Swift (2008). I find their conception powerful, but flawed, and argue that a luck egalitarian conception can account for the appeal of their conception, but is an advance on it. I end by looking at a specific question of educational justice to test the luck egalitarian conception – is there anything inegalitarian about ability grouping? I conclude that, while still needing to have its implications worked out in full, particularly as regards choice, a luck egalitarian conception provides a compelling account of educational equality and reasserts that equality matters for justice in education.

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  • The quantification and visualisation of human flourishing.

    Henley, Lisa (2015)

    Doctoral thesis
    University of Canterbury Library

    Economic indicators such as GDP have been a main indicator of human progress since the first half of last century. There is concern that continuing to measure our progress and / or wellbeing using measures that encourage consumption on a planet with limited resources, may not be ideal. Alternative measures of human progress, have a top down approach where the creators decide what the measure will contain. This work defines a 'bottom up' methodology an example of measuring human progress that doesn't require manual data reduction. The technique allows visual overlay of other 'factors' that users may feel are particularly important. I designed and wrote a genetic algorithm, which, in conjunction with regression analysis, was used to select the 'most important' variables from a large range of variables loosely associated with the topic. This approach could be applied in many areas where there are a lot of data from which an analyst must choose. Next I designed and wrote a genetic algorithm to explore the evolution of a spectral clustering solution over time. Additionally, I designed and wrote a genetic algorithm with a multi-faceted fitness function which I used to select the most appropriate clustering procedure from a range of hierarchical agglomerative methods. Evolving the algorithm over time was not successful in this instance, but the approach holds a lot of promise as an alternative to 'scoring' new data based on an original solution, and as a method for using alternate procedural options to those an analyst might normally select. The final solution allowed an evolution of the number of clusters with a fixed clustering method and variable selection over time. Profiling with various external data sources gave consistent and interesting interpretations to the clusters.

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  • The influence of Confucian values: students’ understandings of classroom behaviours and learning practices in a university in Central China

    Song, Jinhua

    Doctoral thesis
    Auckland University of Technology

    The research aims to investigate the influences of Confucian values on university students’ classroom behaviours and learning practices in Central China. Using a Foucauldian 'genealogical approach' the thesis investigated the extent to which contemporary students in a Western/central university still employ Confucius's ideas in their thinking about education, and in their own learning practices, in the classroom and outside it. The interviews showed how deeply embedded Confucian ideas were: to the extent that they were part of the students' conception of their own identities, despite the inroads of competing ideologies. The results highlighted individual students’ ability to reflect on Confucian values, and demonstrated the significant role played by students’ notice of their own identities in dealing with the influence of Confucian values. The study identified some similarities to and differences from existing literature. It made a new contribution to knowledge by exploring the overlooked element of Confucius' emphasis on joy in learning. It broke new grounds by exploring the tensions in student’s minds as they reconciled Confucian traditions, Maoist ideas and western ideas. The students’ views gave fresh insights into students’ agential powers and structural or cultural influences in the area of learning. This research provided an opportunity for students to reflect on their individual practices in their environment, to voice their concerns, and to uncover their own deep assumptions and tradition by unearthing the influence of Confucian values on their learning ideas, behaviours and practices. All teachers of Chinese students can benefit by being aware of these influences on their students. The research results could be used to develop university policies. Also learning skills support and teaching pace might be made culturally relevant, especially when students come from a Chinese cultural background.

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  • Spatial and temporal genetic structure of the New Zealand scallop Pecten novaezelandiae: A multidisciplinary perspective

    Nunes Soares Silva, Catarina (2015)

    Doctoral thesis
    Victoria University of Wellington

    Knowledge about the population genetic structure of species and the factors shaping such patterns is crucial for effective management and conservation. The complexity of New Zealand’s marine environment presents a challenge for management and the classification of its marine biogeographic areas. As such, it is an interesting system to investigate marine connectivity dynamics and the evolutionary processes shaping the population structure of marine species. An accurate description of spatial and temporal patterns of dispersal and population structure requires the use of tools capable of incorporating the variability of the mechanisms involved. However, these techniques are yet to be broadly applied to New Zealand marine organisms. This study used genetic markers to assess the genetic variation of the endemic New Zealand scallop, Pecten novaezelandiae, at different spatial and temporal scales. A multidisciplinary approach was used integrating genetic with environmental data (seascape genetics) and hydrodynamic modelling tools. P. novaezelandiae supports important commercial, recreational and customary fisheries but there is no previous information about its genetic structure. Therefore, twelve microsatellite markers were developed for this study (Chapter 2). Samples (n=952) were collected from 15 locations to determine the genetic structure across the distribution range of P. novaezelandiae. The low genetic structure detected in this study is expected given the recent evolutionary history, the large reproductive potential and the pelagic larval duration of the species (approximately 3 weeks). A significant isolation by distance signal and a degree of differentiation from north to south was apparent, but this structure conflicted with some evidence of panmixia. A latitudinal genetic diversity gradient was observed that might reflect the colonisation and extinction events and insufficient time to reach migration-drift equilibrium during a recent range expansion (Chapter 3). A seascape genetic approach was used to test for associations between patterns of genetic variation in P. novaezelandiae and environmental variables (three geospatial and six environmental variables). Although the geographic distance between populations was an important variable explaining the genetic variation among populations, it appears that levels of genetic differentiation are not a simple function of distance. Evidence suggests that some environmental factors such as freshwater discharge and suspended particulate matter can be contributing to the patterns of genetic differentiation of P. novaezelandiae in New Zealand (Chapter 4). Dispersal of P. novaezelandiae was investigated at a small spatial and temporal scale in the Coromandel fishery using genetic markers integrated with hydrodynamic modelling. For the spatial analysis, samples (n=402) were collected in 2012 from 5 locations and for the temporal analysis samples (n=383) were collected in 2012 and 2014 from 3 locations. Results showed small but significant spatial and temporal genetic differentiation, suggesting that the Coromandel fishery does not form a single panmictic unit with free gene flow and supporting a model of source-sink population dynamics (Chapter 5). The importance of using multidisciplinary approaches at different spatial and temporal scales is widely recognized as a means to better understand the complex processes affecting marine connectivity. The outcomes of this study highlight the importance of incorporating these different approaches, provide vital information to assist in effective management and conservation of P. novaezelandiae and contribute to our understanding of evolutionary processes shaping population structure of marine species.

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  • Digital Holographic Interferometry for Radiation Dosimetry

    Cavan, Alicia Emily (2015)

    Doctoral thesis
    University of Canterbury Library

    A novel optical calorimetry approach is proposed for the dosimetry of therapeutic radiation, based on the optical technique of Digital Holographic Interferometry (DHI). This detector determines the radiation absorbed dose to water by measurement of the refractive index variations arising from radiation induced temperature increases. The output consists of a time series of high resolution, two dimensional images of the spatial distribution of the projected dose map across the water sample. This absorbed dose to water is measured directly, independently of radiation type, dose rate and energy, and without perturbation of the beam. These are key features which make DHI a promising technique for radiation dosimetry. A prototype DHI detector was developed, with the aim of providing proof-of-principle of the approach. The detector consists of an optical laser interferometer based on a lensless Fourier transform digital holography (LFTDH) system, and the associated mathematical reconstruction of the absorbed dose. The conceptual basis was introduced, and a full framework was established for the measurement and analysis of the results. Methods were developed for mathematical correction of the distortions introduced by heat di usion within the system. Pilot studies of the dosimetry of a high dose rate Ir-192 brachytherapy source and a small eld proton beam were conducted in order to investigate the dosimetric potential of the technique. Results were validated against independent models of the expected radiation dose distributions. Initial measurements of absorbed dose demonstrated the ability of the DHI detector to resolve the minuscule temperature changes produced by radiation in water to within experimental uncertainty. Spatial resolution of approximately 0.03 mm/pixel was achieved, and the dose distribution around the brachytherapy source was accurately measured for short irradiation times, to within the experimental uncertainty. The experimental noise for the prototype detector was relatively large and combined with the occurrence of heat di usion, means that the method is predominantly suitable for high dose rate applications. The initial proof-of-principle results con rm that DHI dosimetry is a promising technique, with a range of potential bene ts. Further development of the technique is warranted, to improve on the limitations of the current prototype. A comprehensive analysis of the system was conducted to determine key requirements for future development of the DHI detector to be a useful contribution to the dosimetric toolbox of a range of current and emerging applications. The sources of measurement uncertainty are considered, and methods suggested to mitigate these. Improvement of the signal-to-noise ratio, and further development of the heat transport corrections for high dose gradient regions are key areas of focus highlighted for future development.

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  • Late Transition Metal Complexes of Pyridyldiphosphines

    Vaughan, Teresa Florence (2015)

    Doctoral thesis
    Victoria University of Wellington

    This thesis provides an account of research into the properties of pyridyldiphosphines with o-xylene and m-xylene backbones. The coordination behaviour of the o-xylene based ligand with platinum, palladium, silver, rhodium and iridium metal centres has been studied, with an emphasis on whether the presence of the pyridyl rings affects the products formed. Platinum and palladium pincer complexes have been synthesised and the intermediates investigated. The formation of trimetallic complexes with these ligands acting as bridging ligands has also been explored. Two new pyridyldiphosphines, o-C₆H₄(CH₂PPy₂)₂ (3) and m-C₆H₄(CH₂PPy₂)₂ (4), and one known pyridyldiphosphine, PPy₂(CH₂)₃PPy₂ (5), have been synthesised via an improved method. Tris(2-pyridyl)phopshine was reacted with a lithium dispersion to give LiPPy₂, which was then reacted with the appropriate dichloride or dibromide compound to yield the desired ligand. The phosphine selenides of 3 and 4 were synthesised and the ¹J PSe values of 738 and 742 Hz indicated these ligands were less basic than PPh₃. While the ligands themselves were not water-soluble, protonation by a strong acid, such as HCl or H₂C(SO₂CF₃)₃, rendered them soluble in water. A series of [MX₂(PP)] complexes (where M = Pt, X = Cl, I, Me, Et, PP = 3, 5; M = Pd, X = Cl, Me PP = 3, 5) were synthesised. Complexes of 3 displayed dynamic behaviour in solution which was attributed to the backbone of the ligand inverting. When [PtMeCl(PP)] (27) was reacted with NaCH(SO₂CF₃)₂ no evidence for the coordination of the pyridyl nitrogens was observed. The synthesis of a series of unsymetrical [PtMeL(PP)]⁺ complexes enabled the comparison of the cis and trans influences of a range of ligands. The following cis influence series was compiled based on ³¹P NMR data of these complexes: Py ≈ Cl > SEt₂ > PTA > PPh₃. Reaction of 27 with NaCH(SO₂CF₃)₂ and carbon monoxide slowly formed an acyl complex, where the CO had inserted in the Pt–Me bond. The bis-chelated complexes [M(PP)₂] where M = Pt, Pd, and [Ag(PP)₂]⁺ were formed. In these complexes 3 acted as a diphosphine ligand and there was no evidence for any interaction between the pyridyl nitrogen atoms and the metal centre. Reaction of 3 with [Ir(COD)(μ-Cl)]₂ formed [IrCl(PP)(COD)] (42). When the chloride ligand in 42 was abstracted, the pyridyl nitrogens were able to interact with the iridium centre faciliating the isomerisation of the 1,2,5,6-ƞ⁴-COD ligand to a 1-к-4,5,6-ƞ³-C₈H₁₂ ligand. The X-ray crystal structure of [Ir(1-к-4,5,6-ƞ³-C₈H₁₂)(PPN)]BPh₄ (43) confirmed the P,P,N chelation mode of the ligand. In solution, 43 displayed hemilabile behaviour, with the pyridyl nitrogens exchanging at a rate faster than the NMR time scale at room temperature. The coordinated pyridyl nitrogen was able to be displaced by carbon monoxide to form [Ir(1-к-4,5,6-ƞ³-C₈H₁₂)(CO)(PP)]⁺. A series of [PtXY(μ-PP)]₂ complexes, where X = Y = Cl, Me, X = Cl, Y = Me and PP = 4, were formed initially when 4 was reacted with platinum(II) complexes. When heated, the dimers containing methyl ligands eliminated methane to form [PtX(PCP)] pincer complexes, X = Cl (49), Me (51). When the chloride ligand in 49 was abstracted no evidence of pyridyl nitrogen coordination was observed. Protonation of 49 did not yield a water-soluble pincer complex. The [PdCl₂(μ-PP)]₂ complex readily metallated when heated to give the pincer complex [PdCl(PCP)]. Given pyridyl nitrogen atoms are known to be good ligands for “hard” metal centres, the ability of the pyridyl nitrogens in 3 and 4 to coordinate to metal centres was investigated. While complexes with chloride ligands were found to form insoluble products, the synthesis of [(PtMe₂)₃(PP)], from the reaction of either 3 or [PtMe₂(PP)] (17) with dimethyl(hexa-1,5-diene)platinum, proceeded smoothly through a dimetallic intermediate. The same reactivity was observed in the synthesis of [(PtMe₂)₂PtMe(PCP)]. In contrast, the cationic heterotrimetallic complexes [{M(COD)}₂PtMe(PP)]²⁺ and [{M(COD)}₂PtMe(PCP)]²⁺, where M = Rh or Ir, were synthesised without the detection of any intermediates. However, dimetallic complexes were formed as part of a mixture when 17 or 51 was reacted with one equivalent of the appropriate metal complex.

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  • Identification of fall-risk factor degradations using quality of balance measurements

    Bassement, Jennifer

    Doctoral thesis
    Auckland University of Technology

    Falls concern a third of the people aged over 65y and lead to the loss of functional ability. The detection of risks factors of falls is essential for early interven- tion. Six intrinsic risk factors of fall: vision, vestibular system, joint range of motion, leg muscle strength, joint proprioception and foot cutaneous propriocep- tion were assessed with clinical tests before and after temporarily degradation. Standing balance was recorded on a force plate. From the force plate, 198 parameters of the centre of pressure displacement were computed. The parame- ters were used as variables to build neural network and logistic regression model for discriminating conditions. Feature selection analysis was per- formed to reduce the number of variables. Several models were built including 3 to 10 condi- tions. Models with 5 or less conditions appeared acceptable but better performance was found with models including 3 conditions. The best accuracy was 92% for a model including ankle range of motion, fatigue and vision contrast conditions. Qualities of balance parameters were able to diag- nose impairments. However, the efficient models included only a few conditions. Models with more conditions could be built but would require a larger number of cases to reach high accuracy. The study showed that a neural network or a logistic model could be used for the diagnosis of balance impairments. Such a tool could seriously improve the prevention and rehabilitation practice.

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  • Quantifying Spatial and Temporal Deposition of Atmospheric Pollutants in Runoff from Different Pavement Types

    Murphy, Louise Una (2015)

    Doctoral thesis
    University of Canterbury Library

    Urban development leads to increased impermeable landscapes that interrupt the hydrological cycle by creating an impermeable barrier to the natural infiltration of precipitation. Precipitate, unable to infiltrate, flows over impermeable surfaces as sheet runoff, carrying the pollutants from the land with it; thus comprising the quality of the stormwater. The runoff is redirected (frequently untreated) to nearby waterways altering their water quality and quantity, thereby, adversely affecting receiving aquatic ecosystems. Suspended solids and elevated heavy metal concentrations in stormwater are the leading causes of water quality degradation in urban waterways in New Zealand. It is widely reported that vehicles and metal roofs are a major direct source of the key pollutants (total suspended solids (TSS) and heavy metals) in stormwater runoff; however, the contribution of atmospheric deposition, as an indirect source, in stormwater runoff is rarely considered. This is principally due to the many uncertainties and challenges with measuring and managing these pollutants in stormwater runoff. Therefore, a monitoring programme into the dynamics controlling atmospherically derived pollutant build-up and wash-off from urban surfaces was conducted. In particular, this research focused on the spatial and temporal variability of Cu, Zn, Pb, and TSS deposition in different land-use areas; the influence of pavement type on atmospherically-deposited pollutant loads in stormwater; and the contribution of wet deposition and dry deposition to the total deposition loads. Impermeable concrete boards (≈ 1 m2) were deployed for 11 months in different land-use areas (industrial, residential and airside) in Christchurch, New Zealand, to capture spatially distributed atmospheric deposition loads in runoff over varying meteorological conditions. Mixed-effect regression models were developed to explain the influence of different meteorological characteristics on pollutant build-up and wash-off dynamics. Next, impermeable asphalt, permeable asphalt, impermeable concrete, and permeable concrete boards were deployed for two months in a residential land-use area to determine the influence of pavement composition and roughness on pollutant loads in stormwater. Finally, wet deposition samples were analysed in an industrial land-use area for 8 months to monitor the contribution of wet deposition to atmospherically-deposited pollutant loads. All samples were analysed for total and dissolved Cu, Zn, Pb, and TSS. Pavement type: Results showed that both impermeable and permeable concrete were efficient at retaining Cu and Zn. Bitumen leaching from the impermeable asphalt was a significant source of Zn to runoff. However, bitumen leaching from the permeable asphalt did not contain elevated Zn loads. Infiltrate from the permeable asphalt provided little/no removal of Cu and Zn. Impermeable asphalt provided greater retention of TSS and Pb over impermeable concrete because its rougher surface entrapped more particulates. TSS and Pb loads were the lowest from the permeable pavements due to the pavers filtering out particulates. Spatial variability: Results showed that all three land-use areas exhibited similar patterns of varying metal and TSS loads, indicating that atmospherically-deposited metals and TSS had a homogenous distribution within the Christchurch airshed. This suggested that the pollutants originated from a similar source and that the surrounding land-use was not an important factor in determining atmospheric pollutant loads to stormwater runoff. Although, higher pollutant loads were found for the industrial area, this was attributed to local topographic conditions rather than land-use activity. Temporal variability: Results illustrated the importance of antecedent dry days on pollutant build-up. Peak rainfall intensity and rain duration had a significant relationship with TSS and Pb wash-off; rain depth had a significant relationship with Cu and Zn wash-off. This suggested that the pollutant speciation phase plays an important role in surface wash-off. Rain intensity and duration influenced particulate pollutants, whereas, rain depth influenced dissolved pollutants. Additionally, mixed-effect models could predict approximately 53-69% of the variation in airborne pollutant loads in runoff. Deposition pathways: Wet deposition was an important contributor of dissolved Zn to stormwater runoff. However, dry deposition was the greatest source of total Cu, Zn, and Pb loads in stormwater runoff. This is principally due to the low annual rainfall in Christchurch limiting pollutant removal via wet deposition unlike dry deposition, which is continually occurring. Understanding the dynamics of airborne pollutant deposition and their contribution to stormwater pollution could help stormwater managers in strategic decision-making processes such as choice of location and installation of different treatment systems.

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  • Dynamic behaviour of brain and surrogate materials under ballistic impact

    Soltanipour Lazarjan, Milad (2015)

    Doctoral thesis
    University of Canterbury Library

    In the last several decades the number of the fatalities related to criminally inflicted cranial gunshot wounds has increased (Aarabi et al.; Jena et al., 2014; Mota et al., 2003). Back-spattered bloodstain patterns are often important in investigations of cranial gunshot fatalities, particularly when there is a doubt whether the death is suicide or homicide. Back-spatter is the projection of blood and tissue back toward the firearm. However, the mechanism of creation of the backspatter is not understood well. There are several hypotheses, which describe the formation of the backspatter. However, as it is difficult to study the internal mechanics of formation of the backspatter in animal experiments as the head is opaque and sample properties vary from animal to animal. Performing ballistic experiments on human cadavers is rarely not possible for ethical reasons. An alternative is to build a realistic physical 3D model of the human head, which can be used for reconstruction of crime scenes and BPA training purposes. This requires a simulant material for each layer of the human head. In order to build a realistic model of human head, it is necessary to understand the effect of the each layer of the human head to the generation of the back-spatter. Simulant materials offer the possibility of safe, well‐controlled experiments. Suitable simulants must be biologically inert, be stable over some reasonable shelf‐life, and respond to ballistic penetration in the same way as the responding human tissues. Traditionally 10-20% (w/w) gelatine have been used as a simulant for human soft tissues in ballistic experiments. However, 10-20% of gelatine has never been validated as a brain simulant. Moreover, due to the viscoelastic nature of the brain it is not possible to find the exact mechanical properties of the brain at ballistic strain rates. Therefore, in this study several experiments were designed to obtain qualitative and quantitative data using high speed cameras to compare different concentrations of gelatine and new composite material with the bovine and ovine brains. Factors such as the form of the fragmentation, velocity of the ejected material, expansion rate, stopping distance, absorption of kinetic energy and effect of the suction as well as ejection of the air from the wound cavity and its involvement in the generation of the backspatter have been investigated. Furthermore, in this study a new composite material has been developed, which is able to create more realistic form of the fragmentation and expansion rate compared to the all different percentage of the gelatine. The results of this study suggested that none of the concentrations the gelatine used in this study were capable of recreating the form of the damage to the one observed from bovine and ovine brain. The elastic response of the brain tissue is much lower that observed in gelatine samples. None of the simulants reproduced the stopping distance or form of the damage seen in bovine brain. Suction and ejection of the air as a result of creation of the temporary cavity has a direct relation to the elasticity of the material. For example, by reducing the percentage of the gelatine the velocity of the air drawn into the cavity increases however, the reverse scenario can be seen for the ejection of the air. This study showed that elastic response of the brain tissue was not enough to eject the brain and biological materials out of the cranium. However, the intracranial pressure raises as the projectile passes through the head. This pressure has the potential of ejecting the brain and biological material backward and create back-spatter. Finally, the results of this study suggested that for each specific type of experiment, a unique simulant must be designed to meet the requirements for that particular experiment.

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  • Critical success factors for outsourced software development projects from a vendor's perspective: A structural equation modelling analysis of traditional plan-based and agile methodologies

    Ahimbisibwe, Arthur (2015)

    Doctoral thesis
    Victoria University of Wellington

    There are many factors proposed as to why software projects fail, one of them is the inappropriate choice of a project management methodology. Although there is an increased range of available management choices, project managers do not frequently consider their alternatives. They tend to narrowly tailor project categorisation systems and use categorisation criteria that are not logically linked with objectives. To address this, this study develops and tests an integrative contingency fit model for contrasting perspectives of traditional plan-based and agile methodologies specifically for outsourced software development projects. In addition, it takes a vendor‘s perspective, rather than the client perspective that is mostly used. Overall, the research seeks to answer these questions: (RQ1) what are the Critical Success Factors (CSFs) for outsourced software development projects from a vendor‟s perspective? (RQ2) What are the differences in these CSFs for traditional plan-driven and agile methodologies towards project success from a vendor‟s perspective? The IT literature reveals two major distinct categories of methodologies: traditional plan-based and agile. Previous research has identified CSFs with respect to project success with mixed findings. The recent increase in popularity of methodologies has shifted the debate, interest and controversy to CSFs that are the factors which are most important to make a methodology successful. While there is an increasing diversity of project types, project contexts and methodologies, the frameworks or theories connecting these are limited. To date software development projects studies have addressed generally one methodology per study and perceived candidate CSFs as a form of reasons of success amidst a wide range of project success criteria. Although contingency theory has been previously argued for outsourced software development projects, empirical models have frequently not fully incorporated contingency as fit or fit as moderation (i.e. traditional vs. agile). This study sought to fill this research gap. Cross-sectional data from 984 senior vendor project managers and team leaders was collected by a global web-based survey. Structural Equation Modelling (SEM) (a multivariate statistical technique, in which parameters are estimated by minimizing the discrepancy between the model-implied covariance matrix and the observed covariance matrix) was used for data analysis. SEM results provide support for several contingency hypotheses theorizing relationships between candidate CSFs and project success. Project management methodology was found to moderate the effects of various CSFs on project success, and in different ways for various success measures. Similarly, the results show the level of project uncertainty moderates the impact of various CSFs on project success, and in different ways for various success measures. Together these findings provide empirical support for contingency as fit and more fully incorporate fit as moderation. The study contributes towards understanding the differences between traditional plan-based and agile project management based on the perceptions of vendor respondents with regard to their client organizations, and also to understanding what are the most significant antecedents of success (the CSFs) in different project contexts. The study also examines the indirect and interaction effects, and the findings contribute towards understanding of the contingency perspective as a framework to be used by project managers and organizations. Practical implications of these results suggest that project managers should tailor project management methodologies according to various project types, which is likely to improve current project success rates.

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  • Inverse problems in astronomical imaging

    Johnston, Rachel Anne (2000)

    Doctoral thesis
    University of Canterbury Library

    The imaging of astronomical objects is limited by atmospheric turbulence, which consists of layers of varying refractive index surrounding the earth. These refractive index fluctuations are a direct consequence of the warming and cooling of air and water vapour in the atmosphere. Wavefronts entering the atmosphere acquire phase distortions, which when propagated result in amplitude fluctuations known as scintillation. Hence the practical manifestation of the atmosphere is a degradation of the signals passing through it, for example it severely limits the resolution of images captured by ground-based telescopes. A variety of solutions, or inverse problems, have been proposed and trialed in the attempt to obtain the best possible images from astronomical telescopes. An orbiting telescope (for example the Hubble space telescope) is one solution. In this case light is captured before it is distorted by the atmosphere. Less expensive ground-based solutions include the post processing of short exposure images and real-time compensation using adaptive optics, both of which are investigated in this thesis. However, the success of an inverse problem lies in the accurate modelling of the processes that give rise to the corresponding forward problem, in this case the random refractive index fluctuations that characterise the atmosphere. Numerical simulation of atmospheric turbulence is achieved using phase screens in which the assumption of Kolmogorov statistics is often made. A previously presented method for modelling Kolmogorov phase fluctuations over a finite aperture, the midpoint displacement method, is both formalised and improved. This enables the accurate generation of atmospheric speckle images for the development and testing of post processing methods. Another aspect of the forward problem is the accurate simulation of scintillation, resulting from the propagation of phase distorted wavefronts. Commonly used simulation methods achieve this by assuming periodic boundary conditions. A technique for the accurate modelling and simulation of scintillation from an aperiodic Kolmogorov phase screen is presented. The more physically justifiable assumption of smoothness is shown to result in a propagation kernel of finite extent. This allows the phase screen dimensions for an accurate simulation to be determined and truncation can then be used to eliminate the unwanted spectral leakage and diffraction effects usually inherent in the use of finite apertures. Deconvolution methods are popular for the post processing of atmospheric speckle images to compensate for the effects of the atmosphere. Conventional deconvolution algorithms are applied when the distortion is known or well-characterised, whereas, blind deconvolution algorithms are used when the distortion is unknown. Conventional deconvolution techniques are not often directly applied to astronomical imaging problems as the distortion introduced by the atmosphere is unknown. However, their extension to blind deconvolution is straightforward and hence their development is valuable. The ill-conditioning of the deconvolution problem requires the addition of prior information, such as positivity, to enable its solution. It is shown that the conventional deconvolution problem can be reformulated as an equivalent quadratic programming problem. Consequently, an accelerated quadratic programming approach is applied and shown to be an improvement to an existing method used for enforcing positivity in deconvolution applications. The main algorithmic differences of the new method are implementation via the fast Fourier transform (FFT) and guaranteed convergence to the constrained minimum. Blind deconvolution is also an interesting problem that may arise in many fields of research. It is of particular relevance to imaging through turbulence where the point spread function can only be modelled statistically, and direct measurement may be difficult. The extension of the quadratic programming method to blind deconvolution, combined with Tikhonov-Miller regularisation (energy constraints), smoothness constraints, penalty terms and statistical priors produced a series of new algorithms. The performance of these algorithms is illustrated on simulated astronomical speckle images. Ground-based adaptive optics (AO) technologies are an alternative to post processing methods and aim to compensate for the distortion introduced by the atmosphere in real-time. Knowledge of the vertical structure of the atmosphere combined with AO provides the potential for compensation over a wide field of view. However, the continually changing nature of atmospheric turbulence places strict requirements on techniques for determining the turbulence structure. The remote sensing of scintillation data to estimate this information is known as scintillation detection and ranging (SCIDAR). Application of SCIDAR methods to the capture and analysis of experimental data, as demonstrated in this thesis, highlighted a number of problems with the technique. Methods for overcoming these difficulties are discussed and demonstrated. Finally, alternative approaches to the estimation of atmospheric turbulence profiles and a proposed new technique are investigated.

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