12,570 results for Doctoral

  • Towards business intelligence in preoperative care: Choice, chance and communication

    Soakell-Ho, MJ (2017)

    Doctoral thesis
    The University of Auckland Library

    BACKGROUND Each year millions of patients worldwide undergo elective surgery to correct a non-life-threatening health condition. For most patients, the risks of surgery and anaesthesia are low, however complications following surgery are an important cause of death. Determining the risk of death or disability is often the remit of the anaesthetist, so accurate information about these risks is needed during the preoperative anaesthetic assessment if informed decisions are to be made. There are limited data about the risk of dying that are relevant to the anaesthetist???s own clinical setting and, as a result, the risks of surgery can be poorly estimated and communicated. The application of routinely collected data (RCD) and business intelligence (BI) may provide anaesthetists with valuable information about perioperative outcomes, and in doing so, further improve the process of shared surgical decision-making during the preoperative assessment. AIM Using RCD, this pragmatic and interpretive study sought to gain actionable insights into perioperative outcomes for patients coming forward for elective surgery and to make these insights available to anaesthetists to support shared decision-making during the preoperative assessment. METHOD A two-year participatory action research (PAR) study was conducted in the Department of Anaesthesia and Perioperative Medicine at Auckland City Hospital, New Zealand. The first of three PAR cycles was undertaken to investigate the appropriateness of an information systems development (ISD) methodology, Multiview2, to inform the development of a BI prototype in the healthcare sector. The second PAR cycle used qualitative interviews with specialist anaesthetists to explore the work of risk communication during the preoperative assessment. The third PAR cycle conducted a single-centre, retrospective cohort study to describe 30-day and 1-year perioperative mortality rates for adult patients who underwent non-cardiac surgery at Auckland City Hospital from 2002 to 2012. The mixed and varied nature of these cycles reflected the interdisciplinary nature of the research. FINDINGS Over the course of the three PAR cycles, the objectives of this study were investigated. First, the stereotypical roles and outcomes for BI development were elicited, which led to a revised Multiview2 framework that is considered appropriate for BI development in the healthcare sector. Second, the interactional and circumstantial influences on anaesthetists??? communications with patients, as part of the shared decision-making that occurs prior to surgery, were found to be varied and complex. Third, 30-day and 1-year perioperative mortality rates for adult patients who underwent non-cardiac surgery at Auckland City Hospital from 2002 to 2012 were found to be comparable to those published internationally. Throughout these research cycles and through the building of a BI prototype, this research shows how one might go about using RCD to provide actionable insights into perioperative outcomes, and how the Multiview2 methodology, with its emphasis on the social and technical aspects of ISD, can be used to support that journey. CONCLUSIONS Shared decision-making and early discussion of the risks, benefits and alternatives to surgery are required to help patients to make the choices about surgery and anaesthesia that best meet their needs. This research has shown that RCD can be used to provide anaesthetists with valuable insights about patient outcomes that are relevant to their own clinical setting to support risk benefit assessment before elective surgery. The BI journey to acquiring these insights requires a unique mix of organisational analysis, sociotechnical analysis, data modelling and technical development and can be facilitated by the Multiview2 methodology. Choice, chance and communication lie at the heart of patient-centred preoperative care, and therefore the value of accurate, timely and relevant information about perioperative outcomes that are derived from RCD and BI should not be underestimated.

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  • Molecular Dynamics Simulations of Dendrimers

    Roberts, Benjamin (2009)

    Doctoral thesis
    The University of Auckland Library

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  • Comparative hypoxia responses and oxygen sensing in galaxiid fishes

    Ulrich, Christine (2017)

    Doctoral thesis
    University of Waikato

    Aquatic ecosystems are inherently characterised by limited oxygen availability and fluctuations in dissolved oxygen concentration, and therefore, environmental hypoxia (i.e. low oxygen conditions) is common. However, in recent decades, the frequency and global expansion of hypoxic environments have increased significantly, owing to intensified anthropogenic impacts on the natural environment. Fish depend on environmental oxygen for oxidative metabolism. In the absence of oxygen, alternative anaerobic mechanisms are in place to maintain energy metabolism. Efficiency and productivity of anaerobic metabolism are, however, comparatively low and may become rapidly insufficient in light of high physiological and metabolic oxygen demand. Correspondingly, substrates used in the oxygen-independent metabolism often are limited, and are converted into metabolites detrimental for the organism. When anaerobic mechanisms fail to meet the energy demand and lethal levels of anaerobic by-products have accumulated, hypoxic death is initiated. In this context, a variety of adaptive hypoxia-response strategies and hypoxia-sensitivities are established in fish, in dependence on species-specific oxygen demand and life strategies, thereby potentially creating very specific environmental niches occupied by distinct species. Accordingly, fish may demonstrate distinct habitat requirements and preferences in relation to the oxygen environment, potentially reflecting species-specific hypoxia sensitivities and response capacities, that may ultimately initiate adaptive radiation. In this context, a range of studies has been undertaken previously in a variety of species, however these are difficult to evaluate in a comparative context due to pronounced taxonomic differences between study species. New Zealand’s galaxiids, however, include species which occupy a wide range of environments. They are closely related and may demonstrate adaptive radiation to particular environments. The three related galaxiid species inanga (Galaxias maculatus), banded kokopu (Galaxias fasciatus) and black mudfish (Neochanna diversus) demonstrate minimised phylogenetic distances, yet exhibit specialised habitat requirements with distinctly different oxygen environments. Thus, it was the overarching goal of this research to establish whether these differences are based upon species-specific oxygen sensitivities and unique hypoxia response strategies and mechanisms, by utilising a novel, comparative combination of behavioural, physiological, molecular and gill morphological studies. To study whether the three closely related galaxiid species exhibit unique behavioural responses upon encountering a hypoxic environment, the ability to sense progressive hypoxia, as well as behavioural responses and hypoxia avoidance thresholds were investigated in a hypoxia-normoxia choice chamber. Inanga demonstrated avoidance of mild hypoxia (< 5.9 mg L-1) and increased the frequency of visits into both the hypoxic and normoxic sides of the choice chamber in severe hypoxia (at dissolved oxygen concentration below 3.6 mg L-1 for hypoxic side and below 1.9 mg L-1 for normoxic side). Banded kokopu responded to progressive hypoxia primarily with an increased frequency of aquatic surface respiration and an elevated swimming speed (body lengths (BL) s-1). Banded kokopu was less averse to hypoxia than inanga, as they displayed a lower hypoxia avoidance threshold and demonstrated horizontal migration from severe hypoxia (< 2.5 mg L-1). By contrast, no avoidance of, or other distinct behavioural response to hypoxia was observed in black mudfish. In conclusion, the three species exhibit unique behavioural responses upon encountering a hypoxic environment which demonstrates not only distinct behavioural response strategies towards hypoxia, but also indicates species-specific hypoxia sensitivities. To investigate whether these distinct hypoxia sensitivities and behavioural responses are based on different metabolic oxygen demands and oxygen consumption profiles, intermittent-flow respirometry was utilised to investigate routine metabolic rates at normoxia, mild and severe hypoxia. Inanga demonstrated oxygen consumption rates similar to banded kokopu, while black mudfish was lower. Inanga and banded kokopu maintained normoxic oxygen consumption in mild hypoxia and exhibited distinct critical oxygen concentrations (Ccrit), below which oxygen consumption rates declined, identifying these species as oxyregulators. Black mudfish was revealed to be an oxyregulator as well, but no Ccrit could be ascertained in this study, possible due to insufficiently severe levels of hypoxia. Inanga displayed the greatest hypoxia sensitivity, reflected in a Ccrit of 5.0 ± 0.4 mg L-1, while banded kokopu was slightly more tolerant to hypoxia with a Ccrit of 4.3 ± 0.1 mg L-1. In conclusion, the three species exhibit distinct oxygen consumption profiles and different critical dissolved oxygen concentrations. To examine whether swimming speed, as a measure of metabolic oxygen demand, and gill morphology are affected by prolonged hypoxia and whether responses to hypoxia are mediated by oxygen sensing neuroepithelial cells (NECs) and by the transcription protein hypoxia inducible factor 1 (HIF-1), the effect of inescapable moderate hypoxia at 5 mg L-1 dissolved oxygen concentration (without access to the water surface) on these parameters was investigated. Swimming speed decreased significantly from 21.6 ± 2.6 to 7.4 ± 2.0 BL min-1 in inanga, while no change was seen in banded kokopu and black mudfish. All three species presented NECs in the gill epithelia; however, hypoxia exposure did not elicit gill morphological adaptations or changes in NEC- and HIF-1 alpha density in any species. Gill morphological traits in black mudfish (i.e. wider respiratory lamellae than in inanga and banded kokopu) indicated an adaptation to emersion and aestivation, frequently observed in this species. HIF-1 alpha protein stabilisation at normoxic conditions indicated distinct differences between mammalian and piscine HIF-1 alpha pathway and hypoxia-inducible gene transcription. In conclusion, the three species exhibit specific adjustments of their swimming speed as a measure of metabolic oxygen demand, however, they do not alter their gill morphology in response to prolonged moderate hypoxia. Furthermore, responses to hypoxia are not mediated by changes in the density of NECs or HIF-1-positive cells. Overall, the findings from this thesis demonstrate that all three species are capable of managing hypoxic environments. In this context, they utilise distinct behavioural response strategies in progressive, escapable hypoxia as well as in prolonged, inescapable hypoxia, and they exhibit different oxygen consumption profiles and hypoxia sensitivities, possibly owing to specific metabolic oxygen demands and distinct behavioural and physiological response capacities. Therefore, the distinct habitat preferences of these galaxiid species are potentially a result of adaptive radiation in the context of the oxygen environment. These observations are relevant in regard to the anthropogenically caused increased expansion of hypoxic environments, affecting the natural habitats of inanga and, potentially, banded kokopu.

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  • Understanding the influence of development interventions on women beneficiaries' perceptions of empowerment: A case study in South Sulawesi, Indonesia

    Muchtar, Adinda Tenriangke (2017)

    Doctoral thesis
    Victoria University of Wellington

    This thesis argues that international development interventions influence the way women perceive empowerment. It does so by looking at aid relationships and the relevance of development interventions. It involves a case study of Oxfam’s Restoring Coastal Livelihoods Project (2010-2015) in South Sulawesi, Indonesia. Efforts to empower women have been channeled through various approaches. However, little has been said about the practice of aid relations within projects and how aid relations work through the ‘aid chain’ and influence women’s perceptions of empowerment. Also, there has not been much said about how, in the intersectionality of aid relationships, women make ‘empowerment’ their own, appropriate it, transform it, adapt it to their stories and needs through their active engagement in projects. The qualitative research which involved a five-month period of ethnographic research found that women beneficiaries perceived empowerment mostly based on their experiences in the project. However, the degree of empowerment is relative to the types of women’s engagement, the nature of activities, and their general understanding of gender relations. The project has brought economic-driven gender awareness by facilitating women’s practical and strategic needs through economic groups. It has also brought empowerment consequences which went beyond the economic dimension. The research highlights the importance of personal, relational, and multidimensional aspects of empowerment in women’s perceptions of empowerment. Efforts to empower women seem to still rely on external intervention to facilitate the process and to deal with existing dynamics of power relations. The findings reassert that women’s empowerment requires enabling internal and external environments to promote women’s awareness of, and capacity for, empowerment. Finally, the thesis underlines that empowerment depends highly on women’s personal experiences, awareness, agency, resources, choice, willingness, and commitment. This research contributes to our understanding of women, aid, and development as it highlights the multidimensional and multi-layered aspects of aid relations and women’s empowerment.

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  • Wittgenstein on Scepticism. An Interpretation of Wittgenstein's On Certainty

    Orłowicz, Agata (2017)

    Doctoral thesis
    Victoria University of Wellington

    The thesis puts forward a new interpretation of Ludwig Wittgenstein’s On Certainty and contrasts it with the standard reading of the book, also known in literature as the Framework Reading. The Framework Reading sees hinge propositions, that is our most basic and indubitable beliefs, as framing our practice of talking about the world, and, therefore, external to this practice. As such, they are seen as not truth-apt, purely regulative in character and our relation to them as non-epistemic. According to the interpretation put forward in this thesis, we should instead see hinges as uncontroversially correct moves in our practice of talking about the world, and, therefore, we should see them as obviously true and playing both a regulative and a descriptive role.

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  • Free vibration analysis of plates and shells by using the Superposition Method

    Mochida, Yusuke (2010)

    Doctoral thesis
    University of Waikato

    This thesis is devoted to investigate the capability of the Superposition Method for obtaining the transient response of plates and the natural frequencies of thin doubly curved shallow shells. The Superposition Method gives accurate results with only a few terms and has proved to be efficient for both cases. To investigate the transient response, all supports of a thin simply supported rectangular plate under self weight are suddenly removed. The resulting motion comprises a combination of the natural modes of a completely free plate. The modal superposition method is used for determining the transient response. The modes and natural frequencies of the plate are obtained using the Superposition Method and the Rayleigh-Ritz method with the ordinary and degenerated free-free beam functions. The W–W algorithm is then used to delimit the natural frequencies from the frequency equation derived in a determinantal form. There is an excellent agreement between the results from both approaches but the modes based on the Superposition Method result in more accurate values with fewer terms, and have shown faster convergence. The results from the Superposition Method may serve as benchmarks for the transient response of completely free plates. The transient response is found to be dominated by the lower modes. The centre of vibration is shifted parallel from the original xy plane by the distance of the first mode of the plate (a rigid body translation) multiplied by the first transient coefficient. In the investigation of doubly curved shells, the natural frequency parameters of thin shallow shells with three different sets of boundary conditions were obtained for several different curvature ratios and two aspect ratios. The solutions to the building blocks, which are subject to simply-supported out-of-plane conditions and shear diaphragm in-plane conditions at all four edges, are represented by series of sine and cosine functions, generated using Galerkin’s method since an exact solution is not available for the doubly curved shells. Once displacement functions for the building blocks are obtained, the prescribed boundary conditions of the actual shell under investigation are then satisfied using the Superposition Method. The rate of convergence is found to be excellent and the results agree well with published results obtained using the Ritz method and those obtained using a Finite Element package, Abaqus. The computations show that it is possible to obtain the first 12 natural frequency parameters of the shallow shells on the rectangular planform with a rapid convergence rate.

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  • Can Justice be Traded for Democracy?

    Foxcroft, Debrin (2017)

    Doctoral thesis
    University of Waikato

    For much of the Twentieth Century, the transition processes of democratizing states have followed a familiar pattern. Outgoing authoritarian regimes relinquished power after extracting the promise of amnesty from the incoming democratic leadership. These authoritarian leaders demanded amnesty for gross human rights violations. The incoming democratic leaders felt like they had no choice. Amnesty has consistently been viewed as a necessary price to pay for democracy. While expedient, in agreeing to amnesty the incoming democratic leaders agreed to sacrifice justice for democracy. This thesis examines the long-term consequences of the amnesty pact on the democratic state and questions whether justice can be sacrificed without ultimately undermining the basis of the democracy. While other studies have focused on the moral implications of amnesty, this work examines the functional realities. Rather than asking whether democratic elites should agree to amnesty, this work asks whether they actually can. Can measures of justice be sacrificed without fundamentally undermining the development and stability of democracy? Can the argument that amnesty is in the interest of the greater good subdue later demands for restoration or retribution? Case study methodology is employed in the examination of the political transitions of Brazil, Chile and South Africa. These countries have each employed different approach to amnesty, though all coming to the same general end. The political and social outcomes in each country speak to the fundamental consequences of amnesty legislation decades after the bargain was struck. The case studies inform my response to the larger theoretical question. This research posits the argument that there are fundamental incompatibilities between the injustice of amnesty and the fundamental requirement of justice that is characteristic of democracy; the current collapse of democracies in Brazil and South Africa, and the fundamental struggles in Chile, are, it is argued, the inevitable results of this impossible trade-off. Building on the data gained from in-country qualitative research, this thesis argues that democratic norms will either be fundamentally weakened by the continued existence and use of amnesty, or, alternatively, democratic norms will be forced to undermine the law or decree itself, compelling leaders to eventually repeal such legislation that ultimately makes democracy, in its basic foundation in justice, impossible. Either situation is highly problematic, creating the potential for instability and the possibility of regime reversal. At its core, this research suggests that the long-term negative consequences of amnesty outweigh the immediate gains made during the transition. For democracy to work, it must be built on a foundation of justice. Amnesty legislation undermines that foundation, and this is simply more than a newly democratizing state can sustain.

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  • An Anatomy of Feedback - A phenomenographic investigation into undergraduate students' experiences of feedback

    McLean, Angela (2012)

    Doctoral thesis
    University of Otago

    Feedback is considered to be a fundamental part of the learning process and is a critical link that connects students’ and teachers’ activities. However, definitions of feedback in the higher education literature are problematic. For example, views of feedback seem to be mechanistic in nature and isolated from the learning context; there is minimal contribution of students’ perspectives in these views; and, there is an assumption on the part of researchers of a common understanding as to what feedback actually is. In addition, the ways in which students respond to feedback are not well understood. Therefore, an objective of this research was to investigate students’ experiences or conceptions of feedback, in order to determine the underlying meaning that feedback has for students. A further objective was to investigate students’ responses or ‘approaches’ to feedback. Data were collected from 28 undergraduate physiotherapy students via individual, semi-structured interviews and then analysed using a phenomenographic approach in order to determine the ‘what’ or referential aspects, and the ‘how’ or structural aspects, of students’ conceptions of feedback. The focus was on the variation across the data, as well as on the relationships between the different experiences in the data. The ways in which students responded to or approached feedback were also analysed with regard to these relationships. One main finding of this study was the identification of a superordinate notion across the data of feedback as ‘information’. However, results indicated that students experienced feedback as ‘information’ in four qualitatively different ways. These differing experiences or conceptions were designated as A: Feedback as ‘telling’, B: Feedback as ‘guiding’, C: Feedback as ‘developing understanding’ and D: Feedback as ‘opening up a different perspective’. These four categories of description represent the outcome space for the research. Each category was subsumed by the next and what was emphasised changed as the categories expanded, demonstrating a relationship of increasing inclusivity and complexity between the categories. Another finding of this study was the variety of factors identified by students as influencing their responses or approaches to feedback. If sufficiently significant, these factors formed barriers to responding to feedback. Furthermore, results revealed a relationship between students’ conceptions of feedback and their responses or approaches to feedback. The relationship was inverted: the more inclusive the conception of feedback, the less barriers there were to responding to feedback. Several conclusions emerge from this research. The results of this research validate the assumption made by researchers of a common understanding of feedback as ‘information’. This feedback information, however, is experienced and responded to in differing ways, relating to students’ underlying conceptions of feedback. In presenting students’ voices, this study provides a view of feedback that is integrally connected to students’ learning contexts. This research also has implications for teachers. Understanding how students conceptualise or experience feedback provides teachers with insights on how to engage students with meaningful feedback. Engagement with feedback, including reflecting on feedback, is a crucial part in developing self-regulation of learning.

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  • Arts, Peacebuilding and Decolonization: A Comparative Study of Parihaka, Mindanao and Nairobi

    Ayindo, Babu (2017)

    Doctoral thesis
    University of Otago

    In the last two decades, research on the ‘power of the arts’ in building peace has increased to a level where one can legitimately make the claim that there now exists an emerging, or perhaps even a resurgent, academic field of arts-based peacebuilding. However, very few studies examine the ‘power of the arts’ in resolving conflicts with emphasis on the particularities of ‘post-colonial’ environments. Specifically, there is a dearth of literature that examines the differences and continuities between historical and arts-based contemporary practices for peace, considering how such factors as colonialism and neo-colonialism have influenced and continue to impact upon practices. Deploying a decolonizing lens, this study seeks to contribute to filling this gap in literature by exploring how arts-based initiatives, while composing works and processes of meaning, beauty, and imagination, simultaneously work towards breaking the apparent cycles of violence in ‘post-colonial’ contexts. The study focuses on arts-practices and approaches in three ‘post-colonial’ sites: Parihaka/Taranaki in Aotearoa/New Zealand; Mindanao region in Philippines; and urban Nairobi in Kenya. It is my thesis that the nature of Indigenous arts practices provides a platform and resource both for a (re)discovery of Indigenous wisdom from colonial legacy (particularly of artistic and cultural destruction) and creative decolonizing responses to conflicts in ‘post-colonial’ environments. To operate at full potential and contribute to epistemic diversity and plurality of arts-based practice, the process of decolonization needs be an integral part of building JustPeace through context-specific initiatives that focus on rediscovery, resistance, conscientization, healing and dialogue. In addition, this manuscript provides valuable insights into peace and nonviolence cultures that predated and have survived colonialism, and continue to constructively explore creative responses within a pervasive colonial matrix of power. As the findings from three case studies show, these Indigenous cultures of peace and nonviolence were, and continue to be, encoded in orature and other hybridized arts. In this spirit, this thesis also reexamines dominant assumptions on the ‘power of the arts’ in building peace and establishes the need to validate, elevate and amplify Indigenous Peacebuilding. The thesis also provides practical suggestions and recommendations to scholars and practitioners engaged in arts-based peacebuilding in ‘post-colonial’ contexts.

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  • A novel central pathway for sympathetic activation in the early stages following an acute myocardial infarction

    Roy, Ranjan Kumer (2017)

    Doctoral thesis
    University of Otago

    Acute myocardial infarction (MI) initiates an adverse and sustained increase in cardiac sympathetic nerve activity (SNA), which begins as early as 30 min after the infarct, provoking arrhythmias and is a leading factor for the high mortality rate within the ensuing hours. The mechanism(s) responsible for the increase in cardiac SNA following MI remain to be fully elucidated, however, increased cardiac SNA likely culminates from interactions between various peripheral neural reflexes and the central integration of these signals, involving several hypothalamic and brainstem nuclei, in particular, the paraventricular nucleus (PVN), supraoptic nucleus (SON), subfornical organ (SFO), nucleus tractus solitarius (NTS), rostral ventrolateral medulla (RVLM), and area postrema (AP). The primary aim of this study was to determine the relative role of these brainstem and hypothalamic nuclei in triggering sympathetic activation in early stages of acute MI. Once the adverse increase in cardiac SNA is fully established, in chronic heart failure, it is essentially irreversible. However, in the early stages following acute MI, it appears possible to effectively prevent or reverse the initial increase in SNA. However, this “early period” is not well defined in the literature. Hence, the first objective of this study was to establish a precise time course of cardiac SNA in early stage of acute MI. The advanced technique of electrophysiology recording directly from the cardiac sympathetic nerve was used to record SNA continuously before and then for four hours following acute MI so as to establish a precise time profile for the increase in SNA following acute MI. The results showed that cardiac SNA began to increase within min following acute MI, reaching significance by 14 min post-MI (34 ± 8% increase in SNA) (n = 8, F (15, 180) = 5.20, P < 0.0001, two-way RM ANOVA). The second objective of this study was to ‘map’ the key brain nuclei responsible for sympathetic activation, in particular the PVN, SON, SFO, AP as well as the NTS, RVLM. Fos protein expression was used as a marker of neuronal activation. Interestingly, as early as 90 min post-MI, all nuclei of interest showed increased neuronal activation. In particular, the parvocellular division of PVN, which comprises pre-autonomic neurons that are heavily implicated in sympathetic activation, showed a higher degree of neuronal activation. e.g. neuronal activation within the parvocellular division of PVN for MI rats was 100% higher than that of sham rats (P = 0.0012, unpaired t-test). Given that the PVN comprises a diverse population of phenotypically different neurons, the third objective of this study was to identify the phenotype of the activated parvocellular neurons using double-label immunohistochemistry. Pre-autonomic parvocellular neurons express oxytocin, vasopressin, endorphin, dynorphin, somatostatin, enkephalin, corticotropin-releasing hormone and growth hormone-releasing hormone. The results revealed that there was increased activation of the parvocellular oxytocin neurons in MI rats (19 ± 2 cells / section, n = 8) than in sham rats (11 ± 2 cells / section, n = 8; P = 0.002, unpaired t-test). Only a sub-population of the parvocellular pre-autonomic oxytocin neurons project to the RVLM, and it is these neurons that have the potential to modulate SNA. Therefore, the fourth objective of this study was to determine whether those parvocellular PVN oxytocin neurons that are activated following MI do project to the RVLM. To do this a retrograde tracer was injected into the RVLM one week prior to the experimental induction of an MI. We then used double-label immunohistochemistry to show that, of all parvocellular PVN oxytocin neurons that project to the RVLM, ~30% are activated following MI (compared to ~0% for sham rats), suggesting that these activated oxytocin neurons likely contribute to the observed increase in SNA following acute MI. To test the final hypothesis that activated oxytocin neurons significantly contribute to sympathetic activation following MI, the technique of electrophysiology was once again used to record changes in cardiac SNA following MI. Importantly, one cohort of MI rats were injected with Retosiban (3 mg / ml), a potent oxytocin receptor antagonist, within 10 min of the acute MI. Remarkably, in those MI rats injected with Retosiban, the increase in cardiac SNA was completely prevented (n = 8, F (2, 15) = 12.37, P = 0.0007, two-way RM ANOVA) and, importantly, mortality rate was reduced from 40% to 11% (P < 0.05, Kaplan-Meier survival analysis). In conclusion, this study provides compelling evidence that PVN oxytocin neuronal activation play a crucial role in triggering an adverse increase in SNA in the early stages following acute MI. Importantly, the results from this study advocate oxytocin receptor blockers as a promising and novel therapeutic strategy for the immediate treatment of MI.

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  • Developing the Capability to Scale and Reuse Learned Knowledge and Functionality in Learning Classifier Systems

    Alvarez, Isidro M. (2017)

    Doctoral thesis
    Victoria University of Wellington

    Learning is an important activity through which humanity has incrementally improved accomplishing tasks by adapting knowledge and methods based on the related feedback. Although learning is natural to humans, it is much more difficult to achieve in the technological world as tasks are often learned in isolation. Software is capable of learning novel techniques and algorithms in order to solve these basic, individual problems, however transferring said knowledge to other problems in the same or related domains presents challenges. Solutions often cannot be enumerated to discover the best one as many problems of interest can be intractable in terms of the resources needed to successfully complete them. However, many such problems contain key building blocks of knowledge that can be leveraged to achieve a suitable solution. These building blocks encapsulate important structural regularities of the problem. A technique that can learn these regularities without enumeration,may produce general solutions that apply to similar problems of any length. This implies reusing learned information. In order to reuse learned blocks of knowledge, it is important that a program be scalable and flexible. This requires a program capable of taking knowledge from a previous task and applying it to a more complex problem or a problem with a similar pattern. This is anticipated to enable the program to complete the new task in a practical amount of time and with reasonable amounts of resources. In machine learning, the degree of human intervention in solving problems is often important in many tasks. It is generally necessary for a human to provide input to direct and improve learning. In the field of Developmental Learning there is the idea known as the Threshold Concept (TC). A TC is transformative information which advocates learning. TCs are important because without them, the learner cannot progress. In addition, TCs need to be learned in a particular order, much like a curriculum, thus providing the student with viable progress towards learning more difficult ideas at a faster pace than otherwise. Therefore, human input to a learning algorithm can be to partition a problem into constituent subproblems. This is a principal concept of Layered Learning (LL),where a sequence of sub-problems are learned. The sub-problems are self-contained stages which have been separated by a human. This technique is necessary for tasks in which learning a direct mapping from inputs to outputs is intractable given existing learning algorithms. One of the first artificial learning systems developed is Learning Classifier Systems (LCSs). Past work has extended LCSs to provide more expressivity by using richer representations. One such representation is tree-based and is common to the Genetic Programming (GP) technique. GP is part of the Evolutionary Computation (EC) paradigm and produces solutions represented by trees. The tree nodes can contain functions, and leaf nodes problem features, giving GP a rich representation. A more recent technique is Code Fragments (CFs). CFs are GP-like sub-trees with an initial maximum height of two. Initially, CFs contained hard-coded functions at the root nodes and problem features or previously learned CFs at the leaf nodes of the sub-trees. CFs provided improved expressivity and scalability over the original ternary alphabet used by LCSs. Additionally, CF-based systems have successfully learned previously intractable problems, e.g. 135-bit multiplexer. Although CFs have provided increased scalability, they suffer from a structural weakness. As the problem scales, the chains of CFs grow to intractable lengths. This means that at some point the LCS will stop learning. In addition, CFs were originally meant to scale to more complex problems in the same domain. However, it is advantageous to compile cross-domain solutions, as the regularities of a problem might be from different domains to that expressed by the data. The proposed thesis is that a CF-based LCS can scale to complex problems by reusing learned solutions of problems as functions at the inner nodes of CFs together with compaction and Layered Learning. The overall goal is divided into the following three sub-goals: reuse learned functionality from smaller problems in the root nodes of CF sub-trees, identify a compaction technique that facilitates reduced solution size for improved evaluation time of CFs and develop a layered learning methodology for a CF system, which will be demonstrated by learning a general solution to an intractable problem, i.e. n-bit Multiplexer. In this novel work, Code Fragments are extended to include learned functionality at the root nodes of the sub-trees in a technique known as XCSCF². A new compaction technique is designed, which produces an equivalent set of ternary rules from CF rules. This technique is known as XCSCF3. The work culminates with a new technique XCSCF*, which combines Layered Learning, Code Fragments and Transfer Learning (TL) of knowledge and functionality to produce scalable and general solutions, i.e. to the n-bit multiplexer problem. The novel ideas are tested with the multiplexer and hidden multiplexer problems. These problems are chosen because they are difficult due to epistasis, sparsity and non-linearity. Therefore they provide ample opportunity for testing the new contributions. The thesis work has shown that CFs can be used in various ways to increase scalability and to discover solutions to complex problems. Specifically the following three contributions were produced: learned functionality was captured in LCS populations from smaller problems and was reused in the root nodes of CF sub-trees. An online compaction technique that facilitates reduced evaluation time of CFs was designed. A layered learning method to train a CF system in a manner leading to a general solution was developed. This was demonstrated through learning a solution to a previously intractable problem, i.e. the n-bit Multiplexer. The thesis concludes with suggestions for future work aimed at providing better scalability when using compaction techniques.

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  • The Impermanence of Obsolescence: Performance Practice Challenges in Works Written for Revival Harpsichord

    Zuelicke, Kristina (2017)

    Doctoral thesis
    Victoria University of Wellington

    The revival harpsichord leads a double life today—enjoying a small fan base on the edge of obsolescence. Most regard the instrument as a twentieth-century foil to the more historically-oriented harpsichords that replaced them by around the mid-1970s. But they are also valued for the repertoire they inspired during the first seventy or so years of the twentieth century, along with their unique capabilities and signature sound. From mid-century onwards, when historical harpsichords began to gain a wider acceptance, revival harpsichords were derided as representing a false notion of teleological progress. Piano building technologies partially adapted to the construction of revival harpsichords have required compromises that ignore basic laws of the physics of sound—including the differences between plucking a string and striking it with hammer. The ontology of a harpsichord type that is piano-informed has led to a widespread conclusion that revival harpsichords are a mistaken concept and are unsuitable even for many of the compositions written for them. The common practice today is to adapt works written for revival harpsichord to historical harpsichords. Limited attention has been given to revival harpsichords in recent academic literature. While mention is made of their historical significance, a current evaluation of the instruments and treatment of revival repertoire has been lacking. This dissertation seeks to critically assess instruments and repertoire by examining perspectives of authors, builders, performers, composers and critics, addressing current issues in performance practice such as the impact of changing instrumentation from revival to historical models. A case is made for valuing revival harpsichords on their own merits as well as applying first-hand knowledge of revival harpsichords to performances of revival repertoire on historical models. This methodology is supported by interviews conducted specifically for this dissertation, playing different revival models and in presenting information neither widely available nor understood, such as a picture of the current availability of revival instruments and details of their restoration. This dissertation contributes to an understanding of revival harpsichords and their repertoire by, firstly, providing up-to-date information on the nature and history of the instrument, as well as highlighting the existence of many revival models, rather than accepting the notion of one standard type. Secondly, revival harpsichord reception is examined within a context of the changing purposes of harpsichord construction after 1889. Lastly, a selection of relevant repertoire is investigated, including Erik Bergman’s 1970 Energien for solo harpsichord (a critical edition of which also forms part of the Appendices), Darius Milhaud’s 1945 Sonata for Clavecin (or Piano) and Violin, op. 257, and Peter Child’s Concerto for Harpsichord and String Quartet (2005), which was written for an Eric Herz revival harpsichord. A tradition already exists of compromising over and discussing which historical harpsichords to use for early music repertoire that spans centuries and the building practices of different geographic regions. This dissertation explores the extent to which revival harpsichords are indeed easily replaced by historical models for revival repertoire, or whether it is sometimes best practice to consider performing these works on the instruments for which they were originally conceived. Alternatively, the performer of a revival work may choose to take certain features of revival instruments into account in developing a performance interpretation on a historical model. Factors hindering performance on historical harpsichords can include performance practice challenges and controversies that arise when transferring pieces to these instruments. Some works defy straightforward alteration and require extensive editing, whereas others are more easily accommodated. Through an examination of repertoire in performance, interviews, and changes in the reception and use of revival harpsichords, this dissertation considers the position and relevance of revival harpsichords today.

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  • Ka ao, ka ao, ka awatea: Emergent Māori experiences of education employment transition

    Mitchell, Moana (2017)

    Doctoral thesis
    Victoria University of Wellington

    The significance of genealogy on Māori transitions between education and employment is often not appreciated as a valid body of knowledge. This research seeks to consider a family history of Māori ‘education towards employment’ experiences and the ensuing conversations that have occurred as part of those experiences. Of major focus is the influence of state policy on systems that have educated Māori to become employable or unemployable, highlighting the often insidious nature of the underlying themes of assimilation, cultural adaptation and integration that have underpinned these policies. Kaupapa Māori theory is engaged as the methodological approach for this research, while a ‘hypothetical dialogue’, counter-storying and Critical Race Theory (CRT) form the theoretical frameworks for analysing the historical and contemporary narratives provided. What this enables is the positioning of a Māori lens with which to understand the inherent values, beliefs and experiential learning that emerge through using autoethnography and more specifically, indigenous autoethnography. This research details a series of conversations that portray the education-employment transitions of different generations of the researcher’s family. It is a highly personalised account shared to provide insight into the effect of policy on these transitions. Accompanied by scholarly commentary, the thematic material is derived from the collection and analysis of primary data such as genealogical and personal experience, which includes the analysis of family narratives and the observation of hui/meetings.1 Secondary data includes literature and review of policy, which provided a baseline for the research. The findings of the research establish deficit thinking as a distinctive, historic and recurring feature of systems that are supposed to educate Māori for employment, but which instead continue to educate and transition a significant number of young Māori into unemployment, underemployment and temporary employment arrangements. These findings contribute to the development of an initiative that supports Māori transitions between education and employment, and which looks to the design of a community hub dedicated to educating whole families at a grassroots level; specifically focusing on a group of parents and whānau studying towards an undergraduate qualification based at their local kura/school.

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  • Investigating Disease Processes in CLN5 and CLN6 Batten Disease

    Best, Hannah (2017)

    Doctoral thesis
    University of Otago

    The neuronal ceroid lipofuscinoses (NCL, Batten disease) are a heterogeneous group of inherited neurodegenerative disorders, clinically characterised by blindness, myoclonic epilepsy, cerebral atrophy, and progressive cognitive and motor decline. To date, there are 13 genetically-identified variants, which collectively represent the most common neurodegenerative disorders of childhood. Despite diverse genetic aetiologies, the NCLs are grouped together based on common principle features, namely progressive neurodegeneration and the lysosomal accumulation of autofluorescent storage material. Currently there is no curative therapy, although there are multiple strategies for controlling disease symptoms. The majority of the NCL-associated genes encode proteins residing in the endosomal/lysosomal pathways, although in many cases the primary functions of these proteins remain largely undefined. Two NCL-related genes of unknown function are CLN5, a soluble lysosomal protein, and CLN6, a transmembrane endoplasmic reticulum (ER) protein. The aims of this work were to identify molecular changes underpinning CLN5 and CLN6 disease and, as a result, help to inform potential therapeutic strategies. In order to investigate the cellular and molecular changes occurring in CLN5 and CLN6 disease, several naturally occurring animal disease models were utilised. Firstly, isolated primary neural cultures from CLN5-/- and CLN6-/- ovine disease models identified perturbations of endosomal, autophagic and lysosomal networks. Using these diseaseassociated alterations as biomarkers, several candidates were trialled for therapeutic efficacy. Firstly, lentiviral mediated gene therapy was used to introduce a wild-type (WT) copy of the mutant gene. Secondly, due to the previously observed autophagic and lysosomal defects, compounds were tested to increase autophagic activity. Both gene therapy and autophagy induction appeared to restore biomarker activity in both the CLN5-/- and CLN6-/- culture models, suggesting disease correction and the possibility of a common therapeutic. Based upon the success of ameliorating autophagy-related disease biomarkers in ovine cell culture models, two therapeutic approaches were tested further in the Cln6nclf mouse model. CLN6 therapy was focused on, as membrane-protein deficiencies are invariably harder to treat with traditional routes, such as gene therapy. In correlation with the sheep model, the Cln6nclf mouse showed autophagy changes, with altered expression of both phagophore and lysosomal markers. Firstly, an alternate approach to CLN6 gene therapy was explored, which looked at modulating the expression of secretable factors lost in disease, alternate to CLN6. This work indicated aberrant regulation of Cln5 and Cln2 in the Cln6nclf mouse, as well as an altered secretome that may be potentiating negative effects to healthy cells. As a second approach, a Food and Drug Administration (FDA) approved compound, gemfibrozil, was used to upregulate autophagy in the Cln6nclf mouse. Treatment reduced the presence of autofluorescent storage material, and decreased inflammatory phenotypes, suggesting gemfibrozil may be of therapeutic benefit in CLN6 Batten disease. Collectively, this data identifies novel common endosomal, autophagy and lysosomal phenotypes, in several models of CLN5 and CLN6, and suggests that modulating the secretome and/or increasing autophagy gene expression may be beneficial for treating CLN6. Further determining the mechanisms underlying disease, as well as the positive gemfibrozil related-changes, will be key to improving and tailoring future therapeutic strategies.

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  • Factors in the effectiveness of anticipatory guilt and shame appeals on health communications: The role of self-construal, regulatory focus and personal cultural orientation

    Nguyen, Sinh Hoang (2017)

    Doctoral thesis
    Victoria University of Wellington

    Negative emotional appeals are commonly used in health messages to cut through the clutter and promote health behaviour change. A research gap exists as to how the emotions of guilt and shame and respective arousals to these emotions act to influence compliance with health messages. Research rarely distinguishes between guilt and shame appeals, different emotional and psychological responses to the two types of appeals, and the main moderators that influence the response to these appeals. To address this gap, this empirical study builds and tests a model for better understanding the processes by which guilt and shame appeals lead to compliance with health messages. Drawing on the theoretical frameworks of cognition, emotion, motivation and research focusing on guilt or/and shame messages and behavioural intention, this study develops an extended model that incorporates influential variables. These include the significant mediating variable of the coping response to emotion, and the moderating variables of self-construal, regulatory focus, and personal cultural orientation. Binge drinking among young adults (aged 16 to 30) is the research context for this study. A series of experiments was conducted to test the research model. Data was collected through an online questionnaire survey among university undergraduates in New Zealand. The main survey collected 301 useable responses including the treatment (n = 266) and control (35) groups. The survey data were analysed using a combination of analysis of covariance and covariance-based structural equation modelling. The results broadly support the proposed model for health communications using guilt and shame appeals. Findings revealed that the coping response has a partial mediating effect on the relationship between guilt/shame arousals and message compliance. Both guilt and shame arousals influence not only message compliance (directly) but also the coping response (indirectly). As predicted, regulatory focus and self-construal were found to moderate guilt/shame arousals from respective emotional appeals. Regulatory focus moderated the levels of shame arousals from shame appeals; that is, prevention-focused individuals exhibited higher shame arousals than their promotion-focused counterparts. Self-construal moderated the levels of guilt arousals from guilt appeals; that is, independent self-construals exhibited higher guilt arousals than their interdependent counterparts. However, there were no interactive effects of self-construal with self-referencing or sources of evaluation on guilt/shame arousals. Personal cultural orientation moderated the impact of shame arousals, but not those of guilt arousals, on message compliance. That is, shame predicted message compliance in collectivists, but not individualists. Interestingly, there was no main differential effect of guilt versus shame arousals in message compliance, but there was an interactive effect of emotion type with personal cultural orientation as previously mentioned. The contributions of this study include refining understanding of guilt versus shame, developing the coping response construct, and identifying key moderators and illustrating their impacts on self-conscious emotional arousals. These contributions open new lines of inquiry in the health communications and discrete emotions literature. First, previous discrete emotions literature has mentioned the effects of unintentional emotions, but this research controlled for these effects. It examined guilt and shame separately through respective emotional arousals rather than emotional appeals. Second, the study extended the model of the effectiveness of guilt versus shame appeals in health communications where the coping response is an instrumental mediator. This mediator influences whether or not the receivers actually take on compliant behaviour. Third, the present study differentiated the effect of guilt versus shame appeals. It provides conditions where such appeals are effective. These conditions are type of emotion interacting with self-construal, and regulatory focus. In addition, the study identified the condition under which guilt or shame arousals are most effective. Effectiveness depends on emotion type and personal cultural orientation. The findings have important practical implications. By understanding how distinct emotion (i.e., guilt versus shame) works and how coping responses (i.e., adaptive versus maladaptive) to these emotions are triggered, practitioners can better structure emotional messaging. Knowledge of message receiver attributes will help them select media appropriately. These attributes are independent versus interdependent, promotion focused versus prevention focused, and individualist versus collectivist. Thus, insights from this research could help health marketers, policy makers as well as health promotion agencies to effectively develop health communications campaigns with more appealing message content and appropriate media selection.

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  • From the Superatom to a Large Variety of Supermaterials: A Theoretical Study

    Schacht, Julia (2017)

    Doctoral thesis
    Victoria University of Wellington

    Metal clusters have been a subject of interdisciplinary research for many years as they act as a bridge between atoms and solid-state materials. In particular, clusters that show distinct thermodynamic stability and unusual atom like behavior, with an electronic shell structure that exhibits a superatomic nature, have attracted considerable attention. The concept of clusters behaving as individual atoms and furthermore mimicking the chemistry of specific elements directly leads to the idea of using those nanoparticles as building blocks for new functional materials. Furthermore, it is interesting that one can change the properties of cluster assembled materials by solely changing the properties of the individual clusters involved. In this work, various factors affecting superatomic assemblies are identified and critically analyzed within the means of first-principles computations. The icosahedral gold cluster Au₁₃[RS(AuSR)₂]₆ has been chosen as a model system to study the tunability of the electronic structure using single atomic impurities. In this context the doped clusters were found to be tunable such, that they reveal atomic properties, e.g. electron affinities similar to individual halogen atoms. In addition, the choice of ligands protecting the clusters is evaluated regarding the stability of the whole cluster and the involvement of the ligands in creating the superatomic structure. The latter was found to be important when thinking of orbital overlap in superatomic assemblies. In a next step the knowledge gained is used to investigate cluster-cluster interactions and detect pairs of clusters that are good candidates to create new superatomic materials. Furthermore basic principles regarding cluster assemblies are established and partially tested in an experimental collaboration studing the structure of an Au₉(PPh₃)₈-C₆₀ assembly. Beyond the investigation of individual gold clusters and gold cluster materials, the electronic structure of binary solid state materials consisting of ligand protected transition metal-chalcogen clusters and fullerenes, as synthesized by Roy et al., is presented. This study shows an intermediate case of non-tunable clusters and furthermore displays the partial loss of the superatomic character of the transition metal chalcogen clusters due to charge transfer. An experimental collaboration conducted in cooperation with the research group of Prof. Beate Paulus in Berlin proceeds even further and investigates the absorption of water on non-superatomic aluminumoxo fluoride clusters.

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  • Transfer Learning for Dataset Shift in Classification and Clustering Problems

    Kumar, Santosh (2017)

    Doctoral thesis
    Victoria University of Wellington

    This research focusses on the dataset shift problem in classification and clustering tasks. This thesis primarily aims to propose a domain-independent transfer learning based solution for dataset shift problem. Machine learning models have already performed well in classification, clustering and regression algorithms. Many traditional machine learning models perform well particularly under a prevailing hypothesis where training and test data instances are drawn from the identical data distribution and same feature space. However, in many real-world applications, insufficiency of labelled data instances is a challenging problem which limits the accuracy of the machine learning models. Furthermore, the distribution of the data varies over time; therefore, the model trained on previous data instances produce less accuracy for testing the newly collected data instances. The problem of dataset shift occurs when the training and testing data instances follow different data distributions or feature spaces. Transfer learning is a suitable framework to resolve the aforementioned limitation by allowing the learning of a model particular to a domain to be used to improve the learning of other models in other domains. This is achieved by over either concurrent of the training of domains or subsequent transfer of knowledge from one domain to the other. This thesis concerns with the dataset shift problems concerning classification and clustering tasks. The overall goal of this thesis is to develop a new domain independent transfer learning approaches that are capable of solving the dataset shift problems in cross-domain classification and clustering tasks. In addition to classification tasks, we present an extensive case study of the novel web-spam features and their classification methods. A semi-supervised cluster-then-level domain adaptation approach is proposed for cross-domain sentiment and web spam classification using transfer learning to handle the covariant data shift (both the labelling and instance-based data shift). Also, the classification accuracy despite the limitation of having very few labelled target domain data instances and entirely unlabelled source domain data instances has been improved. The experimental results reveal that for both cross-domain web spam and sentiment classification tasks the new methods significantly outperform other methods. This thesis also considers dataset shifting in cross-domain documents clustering tasks and proposes a Hybrid Co-clustering based unsupervised transfer learning approach that handles the dataset shift in case of identical and non-identical data distribution. When compared to state-of-art methods, the experimental results reveal a significantly better performance in all cross-domain clustering tasks in both identical and non-identical data distributions. Also, an extension of the co-clustering algorithm demonstrates the flexibility and relative importance of co-clusters by clustering the documents and microarray gene expression data. This extended co-clustering method improves the objective function for overlapping data instances. In particular, the proposed co-clustering approach used to extract the information from DNA Microarray dataset. It extracts co-clusters, and perform Gene Ontology enhancement analysis on the extracted co-clusters. The experimental results reveal that the heavy co-cluster is a co-cluster example worth analyzing in the gene expression data. Moreover, the number of co-clusters obtained by the proposed co-clustering model is comparatively low, although, the dimension of co-clusters extracted is comparatively high. In particular, the number of genes incorporated with any co-cluster is higher than other state-of-the-art algorithms while sustaining low p-values. Which shows that proposed co-clustering model is a companion model capable of extracting co-clusters that may not be easy to obtain with other state-of-the-art algorithms. In the end, this thesis also proposes novel web-spam features and presents an extensive case study which practically demonstrates the current challenges for the web spam classification problem.

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  • Itineraries of Modern Ethiopian Instrumental Music

    Johnson, Lucien (2017)

    Doctoral thesis
    Victoria University of Wellington

    This dissertation explores the way in which Ethiopian musicians of the 1960s and 70s adapted forms such as jazz, soul and Latin music to create a new hybrid instrumental music style variously referred to as Ethio-Jazz or Ethio-Groove. It will then go on to investigate the impact that this music has had, in turn, on musicians in various locations around the world since its reissuing on CD in the late 1990s. The central focus is to investigate and articulate the role of individuals’ musical agency in this narrative, and to ask how, within the context of Ethiopian instrumental music and its offshoots, individual musicians and composers have engaged with, responded to and integrated music from elsewhere into their own musical languages. In particular, it looks at how musicians and composers have approached their own notion of creative individuality when their musical genealogy can be traced via affinities rather than geographic and ethnic inheritances. In adopting various influences these musicians, from both the original generation of Ethiopian musicians in the 60s and 70s who adapted soul, jazz and other American forms, and those from around the world who have in turn been influenced by this style of hybrid Ethiopian music, have had to unlock various technical musical problems, as well as navigate at times treacherous ethical waters and answer to allegations of cultural betrayal and/or appropriation. This dissertation identifies these problematic musical and ethical areas and, in the context of this criticism, it examines various viewpoints on how cultural interaction and exchange take place. The final chapter of this dissertation contextualizes my own creative portfolio, which accompanies this written work. It offers a personal response to the questions that have arisen from my affinity for Ethiopian music and from choosing an approach to composition closely informed by this affinity.

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  • Cross-Layer Media Access Control in Wireless Body Area Networks Using Fuzzy Logic and Evolutionary Computation

    Nekooei, Seyed Mohammad (2017)

    Doctoral thesis
    Victoria University of Wellington

    Over the past decade, advances in electronics, computer science, and wireless technologies have facilitated the rapid development of Wireless Body Area Networks (WBANs). WBANs consist of various sensors that are attached on or even implanted in the human body to improve health care and the quality of life. WBANs must provide high-quality communication in terms of both reliability and performance, in order to bring timely medical help to patients. Commonly used communication standard in WBANs is IEEE 802.15.4. However, due to poor channel quality in WBANs, this standard is limited in reliability and performance. To address this issue, cross-layer techniques for Media Access Control (MAC) have attracted substantial research attention in recent years. Aimed at developing cross-layer MAC technologies, Fuzzy Logic Controllers (FLCs) have been widely utilised to effectively and efficiently process information from different layers in WBANs. However, existing FLCs have mostly focused on improving communication reliability while ignoring the importance of network performance. To improve both the reliability and performance of MAC protocols in WBANs, this thesis introduces a new design of cross-layer FLC, called Cross-Layer Fuzzy logic based Backoff system (CLFB), to improve reliability by reducing the collision rate and increasing the packet delivery ratio. CLFB can also enhance the network performance in terms of throughput in WBANs while maintaining packet delays at a reasonable level by considering both channel condition and application requirements. Through the proper use of FLCs as an extension of the standard exponential back-off algorithms, CLFB is experimentally shown to achieve a high level of adaptability. This thesis also proposes an evolutionary approach to automate the design of FLCs for CLFB in WBANs. With the goal of improving network reliability while keeping the communication delay at a low level, we have particularly studied the usefulness of three coding schemes with different levels of flexibility, which enables us to represent alternative design of FLCs as candidate solutions in evolutionary algorithms. The influence of fitness functions that measure the effectiveness of each possible FLC design has also been examined carefully in order to identify useful FLCs. Moreover, we have utilised surrogate models to improve the efficiency of the design process. In consideration of practical usefulness, we have further identified two main design targets. The first target is to design effective FLCs for a specific network configuration. The second target covers a wide range of network settings. In order to examine the usefulness of our design approach, we have utilised and experimentally evaluated two popularly used evolutionary algorithms, i.e. Particle Swarm Optimisation (PSO) and Differential Evolution (DE). This thesis finally proposes a two-level control scheme at both the sensor level and the coordinator level to further improve communication quality in WBANs. The sensor-level FLC controls contention based channel access and the coordinator-level FLC controls contention free channel access. This two-level FLC architecture can effectively enhance the cooperation between sensors and the coordinator such that both the reliability and performance of the network can be significantly improved. We also studied the use of cooperative coevolutionary approach to automate the design of our twolevel control scheme. With the goal of effectively designing useful FLCs, we have particularly investigated different collaborator selection methods for our cooperative coevolutionary approach, which enable us to effectively select collaborators while evaluating the candidate FLC design in each sub-population. Specifically, we show that network knowledge can help our evolutionary design approach to select collaborators more effectively.

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  • Methodological Issues in the Geochemical Characterisation and Morphological Analysis of Stone Tools: A Case Study from Nuku Hiva, Marquesas Islands, East Polynesia

    McAlister, Andrew (2011)

    Doctoral thesis
    The University of Auckland Library

    In this thesis, three methodological issues pertaining to the geochemical analysis and characterisation of stone tools were investigated. The first consisted of evaluating the potential of Portable X-Ray Fluorescence (PXRF) analysis as a means of characterising archaeological basalt adzes. Several of the methods currently used to analyse stone tools require the partial destruction of specimens and are comparatively expensive, factors which tend to impose limits on the quantity of specimens that can be analysed. In contrast, PXRF technology is relatively inexpensive and non-destructive. The initial testing of the PXRF instrument was unsatisfactory and found the in-built calibration software to be the main limiting factor. Substantially improved results were obtained by processing the raw spectra data independently. The second part of this study assessed multivariate methods of discriminating among volcanic stone sources. Two techniques, Discriminant Function Analysis (DFA) and Classification Tree (CT) analysis were examined. The implementation of CT analysis developed in this study incorporated Support Vector Machine (SVM) algorithms to determine optimum node divisions. Both of the techniques performed well. However, CT analysis was found to possess several advantages over DFA; it was more robust to unequal and skewed data distributions and the tabular and graphical results were conducive to interpretation and evaluation. The third part of this research involved applying the methodological findings to investigate the distribution of stone tools on the Marquesan island of Nuku Hiva in East Polynesia. Stone adzes collected from late-prehistoric (i.e., post ??? A.D. 1600) contexts at four valleys on Nuku Hiva were geochemically and morphologically analysed. The assemblages were found to have derived from six distinct stone sources, five local Nuku Hiva sources and one on Eiao, an island approximately 100 km to the north. Almost onehalf of the adzes were imported from Eiao and were common in all of the valleys. In contrast, tools made from local stone were not widely distributed far from their source areas. The morphological analysis found that, while the full range of forms were made from both local and imported materials, stone from Eiao appears to have been preferred for some adze forms that are thought to be functionally distinct.

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