1,504 results for Doctoral, Modify

• ### Improving Clustering Methods By Exploiting Richness Of Text Data

#### Wahid, Abdul (2016)

Doctoral thesis
Victoria University of Wellington

Clustering is an unsupervised machine learning technique, which involves discovering different clusters (groups) of similar objects in unlabeled data and is generally considered to be a NP hard problem. Clustering methods are widely used in a verity of disciplines for analyzing different types of data, and a small improvement in clustering method can cause a ripple effect in advancing research of multiple fields. Clustering any type of data is challenging and there are many open research questions. The clustering problem is exacerbated in the case of text data because of the additional challenges such as issues in capturing semantics of a document, handling rich features of text data and dealing with the well known problem of the curse of dimensionality. In this thesis, we investigate the limitations of existing text clustering methods and address these limitations by providing five new text clustering methods--Query Sense Clustering (QSC), Dirichlet Weighted K-means (DWKM), Multi-View Multi-Objective Evolutionary Algorithm (MMOEA), Multi-objective Document Clustering (MDC) and Multi-Objective Multi-View Ensemble Clustering (MOMVEC). These five new clustering methods showed that the use of rich features in text clustering methods could outperform the existing state-of-the-art text clustering methods. The first new text clustering method QSC exploits user queries (one of the rich features in text data) to generate better quality clusters and cluster labels. The second text clustering method DWKM uses probability based weighting scheme to formulate a semantically weighted distance measure to improve the clustering results. The third text clustering method MMOEA is based on a multi-objective evolutionary algorithm. MMOEA exploits rich features to generate a diverse set of candidate clustering solutions, and forms a better clustering solution using a cluster-oriented approach. The fourth and the fifth text clustering method MDC and MOMVEC address the limitations of MMOEA. MDC and MOMVEC differ in terms of the implementation of their multi-objective evolutionary approaches. All five methods are compared with existing state-of-the-art methods. The results of the comparisons show that the newly developed text clustering methods out-perform existing methods by achieving up to 16\% improvement for some comparisons. In general, almost all newly developed clustering algorithms showed statistically significant improvements over other existing methods. The key ideas of the thesis highlight that exploiting user queries improves Search Result Clustering(SRC); utilizing rich features in weighting schemes and distance measures improves soft subspace clustering; utilizing multiple views and a multi-objective cluster oriented method improves clustering ensemble methods; and better evolutionary operators and objective functions improve multi-objective evolutionary clustering ensemble methods. The new text clustering methods introduced in this thesis can be widely applied in various domains that involve analysis of text data. The contributions of this thesis which include five new text clustering methods, will not only help researchers in the data mining field but also to help a wide range of researchers in other fields.

View record details
• ### Intertextuality in Kenyan Policy Discourse on the Rights of Women

#### Aberi, George (2016)

Doctoral thesis
Victoria University of Wellington

The investigative aim of this thesis is to explore the recontextualization of the normative discourse of gender equality in Kenya’s policy discourse of women’s rights. Its purpose is threefold: Firstly, it attempts to examine the different ways in which policy makers use language in the course of interpreting and implementing gender equality policies. This includes a focus on both the linguistic and rhetorical/discursive strategies that these policy makers employ for such functions as endorsing, negotiating, legitimating, or even contesting given policy proposals. Secondly, the thesis endeavours to bring to light the different and changing conceptions of gender (in)equality espoused by the various policy actors involved in Kenya’s policy discourse of women’s rights over a critical ten-year period between 1995 and 2005. These policy actors include the Kenyan government; women’s non-governmental organizations (NGOs) who actively seek to influence government policy; and the United Nations’ organizations with responsibility for ensuring the implementation of women’s human rights. Thirdly, the thesis attempts to show the extent to which policy initiatives proposed by the human rights-based women’s NGOs in Kenya are taken up in the texts produced by the Kenyan government. In order to gain a better understanding of the discursive interactions between and amongst the policy actors in this study, an intertextual approach to Norman Fairclough’s model of critical discourse analysis (CDA) was used. The thesis drew discourse samples for analysis from the Kenyan government’s periodic reports detailing progress towards fully meeting the terms of the Convention on the Elimination of Discrimination Against Women (CEDAW); the documents produced by the Committee overseeing the Convention that provided assessment of the Kenyan government’s reports; the Kenyan government’s official texts on gender policy; and Kenyan women NGOs’ annual reports and other texts. Though many scholars and researchers of women’s rights praise the UN Committee’s imperatives for bringing about policy changes concerning women’s rights globally, the findings from this study confirm that the Committee for CEDAW has only textual power, and that it lacks enforcement powers to ensure the implementation of the universal rights of women within the local milieu. In a similar vein, this study demonstrates that though the women’s NGOs play a significant role both in terms of identifying important areas of concern for policy intervention, and in necessitating changes in the genres of the national government, their participation has largely failed to ensure the Kenyan government’s epistemological shift from its current state of recognizing the existence of women’s rights, to the phase of implementing them. This thesis also establishes that differing conceptions of gender (in)equality and ideological differences between the Committee for CEDAW and the Kenyan government tend to influence both the Committee’s and the Kenyan government’s use of varied discourses, genres, and styles, with the intent of manipulating to outmanoeuvre one another. This means that both the Kenyan government and the Committee live in different worlds, suggesting a continuing gap between the Committee’s normative knowledge of women’s rights to gender equality, and the Kenyan government’s cultural relativist perspectives concerning such rights. As a solution to these power struggles and political differences that derail policy making on gender equality, this study recommends the need both for the Committee and the Kenyan government to employ a reflexive and pragmatic mix of both the universalist and cultural relativist approaches to gender equality. This will bring forth shared areas of interest concerning women’s rights between the UN and the Kenyan government, based on their applicability within the local context. Moreover, such an approach will create a possibility for the Committee to understand the Kenyan government’s cultural relativist/competing discourse of women’s rights as another way of conceiving gender equality (i.e. productive power-knowledges), rather than viewing them as irrelevant cultural claims that stand in stark opposition to the universal understandings of women’s rights to gender equality. Likewise, the aforesaid reflexive and pragmatic mix of approaches will help the Kenyan policy makers to develop a more critical and nuanced view of the universal approaches to gender equality, thereby reducing their varied forms of resistance to gender equality via subtle evasive strategies. Methodologically, this thesis shows how a comparative intertextual approach to Fairclough’s model of critical discourse analysis can be used as a framework for establishing the relations between policy text and context. This framework includes the micro-level of textual/linguistic analysis, the meso level of discursive interactions, and the macro level of socio-cultural practice at the local, institutional, and societal levels. Theoretically, the thesis demonstrates the different ways in which particular philosophical arguments and emancipatory concepts from Foucault’s theory of governmentality and transnational feminist rhetorical theory can be combined and exploited by linguists to promote different ways of theorizing and thinking concerning the development of policies for promoting gender equality.

View record details
• ### Tama Samoa Stories: Experiences and Perceptions of Identity, Belonging and Future Aspirations at Secondary School

#### Rimoni, Fuapepe (2016)

Doctoral thesis
Victoria University of Wellington

This thesis investigates the experiences of twelve strong, articulate and thoughtful tama Samoa (Samoan boys) through their participation in secondary schools and lives outside the classroom and through the stories of others. The study looked at how the students enacted their identities as Samoans, as learners and as young men who are anticipating the future. The study is premised on the view that Pacific identities are fluid, diverse, multi-dimensional and include a range of different perspectives relating to social class, ethnicity, culture and gender. Such a view of identity as complex is not generally taken into consideration in the literature on educational success and achievement of Pacific students in New Zealand. The study employed a phenomenological qualitative design, using focus groups and semi-structured interviews by talanoa (conversations). As the study involved a group of indigenous tama Samoa, the Samoan fa’afaletui method was used. Participants were a group of twelve tama Samoa in three Wellington secondary schools and their twelve nominated persons. The study found that there are key aspects to making the experiences of tama Samoa positive and successful within the secondary school. These include acknowledging tama Samoa and their multiple identities while attending secondary school; supporting the development of a sense of belonging through everyday interactions with peers and teachers, and affirming the belief by tama Samoa that secondary school socialisation serves to help them make future decisions. This study argues that the experiences of tama Samoa are deeply embedded within wider social, economic and political trends. Indeed, their “voices” are shaped in part by these broader forces that construct and represent them as being historically “disadvantaged” and socio-economically “underserved.” Further, this study advocates for the diverse voices of tama Samoa, along with their experiences, stories, hopes, aspirations and dreams to be brought to light and placed alongside the official accounts of Pacific “disadvantage” to enable more balanced critical discourses taking place. It is hoped that this study will offer further insights into the experiences of tama Samoa in the New Zealand secondary school context, from which valuable knowledge is derived to inform and support schools in improving the New Zealand secondary school experiences of Samoan adolescent boys.

View record details
• ### Interference Alignment and Cancellation in Wireless Communication Systems

#### Ustok, Refik (2016)

Doctoral thesis
Victoria University of Wellington

View record details
• ### Asymptotic methods of testing statistical hypotheses

#### Nguyen, Thuong (2017)

Doctoral thesis
Victoria University of Wellington

For a long time, the goodness of fit (GOF) tests have been one of the main objects of the theory of testing of statistical hypotheses. These tests possess two essential properties. Firstly, the asymptotic distribution of GOF test statistics under the null hypothesis is free from the underlying distribution within the hypothetical family. Secondly, they are of omnibus nature, which means that they are sensitive to every alternative to the null hypothesis. GOF tests are typically based on non-linear functionals from the empirical process. The first idea to change the focus from particular functionals to the transformation of the empirical process itself into another process, which will be asymptotically distribution free, was first formulated and accomplished by {\bf Khmaladze} \cite{Estate1}. Recently, the same author in consecutive papers \cite{Estate} and \cite{Estate2} introduced another method, called here the {\bf Khmaladze-2} transformation, which is distinct from the first Khmaladze transformation and can be used for an even wider class of hypothesis testing problems and is simpler in implementation. This thesis shows how the approach could be used to create the asymptotically distribution free empirical process in two well-known testing problems. The first problem is the problem of testing independence of two discrete random variables/vectors in a contingency table context. Although this problem has a long history, the use of GOF tests for it has been restricted to only one possible choice -- the chi-square test and its several modifications. We start our approach by viewing the problem as one of parametric hypothesis testing and suggest looking at the marginal distributions as parameters. The crucial difficulty is that when the dimension of the table is large, the dimension of the vector of parameters is large as well. Nevertheless, we demonstrate the efficiency of our approach and confirm by simulations the distribution free property of the new empirical process and the GOF tests based on it. The number of parameters is as big as $30$. As an additional benefit, we point out some cases when the GOF tests based on the new process are more powerful than the traditional chi-square one. The second problem is testing whether a distribution has a regularly varying tail. This problem is inspired mainly by the fact that regularly varying tail distributions play an essential role in characterization of the domain of attraction of extreme value distributions. While there are numerous studies on estimating the exponent of regular variation of the tail, using GOF tests for testing relevant distributions has appeared in few papers. We contribute to this latter aspect a construction of a class of GOF tests for testing regularly varying tail distributions.

View record details
• ### Fostering incidental vocabulary uptake from audio-visual materials: The role of text comprehension

#### Nguyễn, Chí Đức (2017)

Doctoral thesis
Victoria University of Wellington

This research project explores various factors that may influence the rate of incidental foreign/second language (L2) vocabulary acquisition from audio-visual materials, with a special focus on procedures that enhance learners’ comprehension of these input materials. Informed by relevant theories and research findings in the fields of L2 listening comprehension and incidental vocabulary acquisition, I investigate the effects of having learners (a) view a TED Talks video twice rather than once, (b) sum up the content of the video before watching it a second time, (c) watch TED Talks videos on the same subject in order to increase familiarity with that subject, and (d) exchange summaries of TED Talks videos with peers so as to assist each other’s subsequent processing of those videos. As these interventions are all deemed to facilitate L2 listening comprehension, they are also expected to create favourable conditions for incidental vocabulary uptake to occur. The effects on incidental vocabulary acquisition of the above interventions were gauged in a series of classroom experiments with Vietnamese EFL learners. Although vocabulary uptake was generally far from spectacular, all of the tested procedures were found to result in statistically significant vocabulary gains. The insertion of the output tasks (i.e., the summary activities) was particularly useful. First, they helped to enhance the learners’ text comprehension. Second, they created opportunities for the learners to use newly met words and thus consolidate their knowledge of these lexical items. A thread through the experimental data is the strong association between the learners’ vocabulary uptake and their comprehension of the input content. The findings from this research project are consistent with several established notions, models and theories in the fields, including Ausubel’s Advance Organizer (1978), Hulstijn and Laufer’s Involvement Load Hypothesis (2001), Krashen’s Input Hypothesis (1985), Nation’s Vocabulary Generation (2013), Swain’s Output Hypothesis (2005), and Wittrock’s Model of Generative Teaching of Comprehension (1991). However, there are also findings that go beyond the core tenets of these, and that can further our understanding of how learners process new lexical items in meaning-focused input and output tasks. Regarding pedagogical implications, this research project confirms that fostering L2 listening comprehension creates favourable conditions for incidental vocabulary acquisition to happen, and that the aforementioned classroom procedures are facilitative in this regard, albeit to different degrees.

View record details
• ### Discriminative Stimulus Properties of MDMA: The Role of Serotonin and Dopamine

#### Webster, Jeremy (2016)

Doctoral thesis
Victoria University of Wellington

Rationale: ±3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) produces unique and complex subjective effects which distinguish it from other recreationally used drugs. An understanding of the neurochemical mechanisms that underlie these effects is important in order to assess the potential for MDMA abuse and to inform researchers exploring of the drug’s therapeutic potential. The present thesis investigated the neurochemical mechanisms underlying the subjective effects of MDMA using drug discrimination procedures in laboratory animals. Despite evidence that training dose can markedly impact the results of drug discrimination studies, the impact of training dose on the discriminative stimulus properties of MDMA has been largely overlooked. The broad aims of these experiments were 1) to test the ability of two different doses of MDMA to support drug discrimination learning, and 2) to determine the role of serotonin (5-HT) and dopamine (DA) neurotransmitter systems in producing the discriminative stimulus effects of each MDMA training dose. Methods: Groups of rats were trained to discriminate MDMA (1.5 or 3.0 mg/kg) from saline or to discriminate MDMA (1.5 or 3.0 mg/kg) from amphetamine (0.5 mg/kg) and saline, using two- or three-lever, food-reinforced drug discrimination procedures. The first experiments determined the impact of training dose on the acquisition of the MDMA discrimination. Reliability of the discrimination was assessed by measuring the impact of changes in acquisition criteria. Once the discrimination had been acquired, generalisation tests were carried out in two-lever experiments with the SSRIs, fluoxetine and clomipramine, the 5-HT2 agonists, mCPP and DOI, and the 5-HT1 agonists, 8-OH-DPAT and RU-24969, to investigate the role of 5-HT in the discriminative stimulus effects of 1.5 mg/kg vs 3.0 mg/kg MDMA. Next, the role of DA was investigated in further generalisation test sessions with the DA releasing stimulant, AMPH, the non-selective D1/D2 agonist, apomorphine, the D1 agonist, SKF38393, and the D2 agonist, quinpirole. Finally, experiments were carried out in which the ability of the 5-HT2A antagonist, ketanserin, the 5-HT1B/1D antagonist, GR-127935, the 5-HT1A antagonist, WAY100635, the D1 antagonist, SCH23390, and the D2 antagonist, eticlopride, to attenuate the discriminative stimulus effects of 1.5 mg/kg vs 3.0 mg/kg MDMA was assessed. Results: A higher training dose of MDMA was associated with a more rapid acquisition of drug discrimination in both the two- and three-lever tasks, and significant differences were observed with respect to the ability of each dose of MDMA to maintain consistently accurate discrimination across both tasks. All of the serotonin agonists that were tested generalised to the discriminative stimulus effects of 1.5 mg/kg MDMA in a two-lever discrimination task. In contrast, only agonists for 5-HT1A or 5-HT2A receptors generalised to the discriminative stimulus effects of 3.0 mg/kg MDMA. Non-selective dopamine agonists generalised to the discriminative stimulus effects of 3.0 mg/kg but not 1.5 mg/kg MDMA, whereas selective D1 and D2 agonists failed to generalise to the discriminative stimulus effects of either training dose. None of the DA or 5-HT antagonists tested had a marked impact of the discrimination of 1.5 mg/kg MDMA whereas administration of a D2 antagonist produced a small but significant attenuation on the discriminative stimulus effects of 3.0 mg/kg MDMA. Conclusions: The results of the present thesis suggest that the discriminative stimulus effects of MDMA may change both quantitatively and qualitatively as a function of dose. The subjective effects produced by lower doses appear to be mediated primarily via serotonergic mechanisms, whereas higher doses may involve the additional recruitment of dopaminergic mechanisms. These findings have implications for our understanding of MDMA in terms of the drug’s potential for dependence and abuse.

View record details
• ### Heke Mai Ki Ahau Nei E! Roka Paora's Contributions To Tukunga Iho A Te Whānau-a-Apanui And Te Reo O Te Whānau-a-Apanui

#### Richards, Parehau (2016)

Doctoral thesis
Victoria University of Wellington

Throughout the twentieth century Te Whānau-a-Apanui scholars continued to assert distinctive features of Te Whānau-a-Apanui identity through both literary and non-literary texts. Roka Pahewa Paora contributed to this important work by producing Māori texts for Māori language students and the community. Those texts became well-known in the field of Māori education for asserting distinctive features of te reo o Te Whānau-a-Apanui. This thesis explores a selection of tukunga iho a Te Whānau-a-Apanui, kōrero tuku iho and taonga tuku iho, to illustrate how Roka and other Te Whānau-a-Apanui scholars before and after her have embraced and passed down tukunga iho a Te Whānau-a-Apanui by renewing or extending core elements, otherwise referred to in this thesis as the iho, of earlier tukunga iho a Te Whānau-a-Apanui. Specifically, this thesis examines Roka’s published writings ‘Ka Haere a Hata Mā Ki te Hī Moki’ (Paora, 1971) and ‘He Kōrero Mō te Mahi Wēra i Te Whānau-a-Apanui’ (Paora in Moorfield, 1992) as extensions of earlier tukunga iho a Te Whānau-a-Apanui about moki and whales. My analysis focuses on how Roka applied the knowledge, language and history of earlier tukunga iho a Te Whānau-a-Apanui to her writings to assert te reo o Te Whānau-a-Apanui. Therefore, this thesis uses a tukunga iho framework to illustrate familial and intellectual connections between and across a selection of tukunga iho a Te Whānau-a-Apanui and the tribal scholars that produced them. Roka’s writings and archive are repositories of important tukunga iho and provide connections to tribal, Māori and non-Māori scholars who offer insights and interpretations of mātauranga Māori that have been applied to Māori studies paradigms and kaupapa Māori. This wider range of knowledge, language and historical sources also help me to show how tukunga iho a Te Whānau-a-Apanui contain important insights into the social, cultural and economic contexts in which my ancestors embraced, extended and passed down tukunga iho a Te Whānau-a-Apanui. Overall, this thesis offers twenty-first century interpretations of tukunga iho a Te Whānau-a-Apanui and how they assert te reo o Te Whānau-a-Apanui.

View record details
• ### Characterising the Anthropocene: Ecological Degradation in Italian Twenty-First Century Literary Writing

#### Macilenti, Alessandro (2015)

Doctoral thesis
Victoria University of Wellington

The twenty-first century has witnessed the exacerbation of ecological issues that began to manifest themselves in the mid-twentieth century. It has become increasingly clear that the current environmental crisis poses an unprecedented existential threat to civilization as well as to Homo sapiens itself. Whereas the physical and social sciences have been defining the now inevitable transition to a different (and more inhospitable) Earth, the humanities have yet to assert their role as a transformative force within the context of global environmental change. Turning abstract issues into narrative form, literary writing can increase awareness of environmental issues as well as have a deep emotive influence on its readership. To showcase this type of writing as well as the methodological frameworks that best highlights the social and ethical relevance of such texts alongside their literary value, I have selected the following twenty-first century Italian literary works: Roberto Saviano’s Gomorra, Kai Zen’s Delta blues,Wu Ming’s Previsioni del tempo, Simona Vinci’s Rovina, Giancarlo di Cataldo’s Fuoco!, Laura Pugno’s Sirene, and Alessandra Montrucchio’s E poi la sete, all published between 2006 and 2011. The main goal of this study is to demonstrate how these works offer an invaluable opportunity to communicate meaningfully and accessibly the discomforting truths of global environmental change, including ecomafia, waste trafficking, illegal building, arson, ozone depletion, global warming and the dysfunctional relationship between humanity and the biosphere.

View record details
• ### An investigation of foreign exchange risk management by exporting small and medium sized enterprises

#### Dang, Vu (2015)

Doctoral thesis
Victoria University of Wellington

Previous studies on foreign exchange (forex) risk management have tended to focus on multinational enterprises; while how SMEs manage their forex risk is still largely unexplored. As small and medium sized enterprises (SMEs) are increasingly involved in international markets, they have become a new research setting on forex risk management. Given that SMEs have limited access to resources, skills and capabilities, internal hedging techniques could be favoured by SMEs. There is limited research on this matter, and the extant literature on forex management generally considers derivatives as major hedging techniques for large firms. This thesis primarily investigates how exporting SMEs manage forex risk. In addition, approaches to forex management could be changed as a firm becomes more experienced internationally. Following the basic principles of internationalisation theory, the thesis also examines the impact of the internationalisation degree of the firm on forex management decisions. This thesis sheds new light on SMEs’ hedging practices by providing a better understanding of SMEs’ choices of forex risk management. Three research questions have been raised: (1) what determinants influence SMEs’ choice to hedge as a way of managing forex risk; (2) what strategies do SMEs use when they choose hedging to manage forex exposure; and (3) how does the degree of internationalisation impact the choice of forex management. The thesis draws on two theoretical perspectives to help address these overarching questions. It extends the use of the resource-based view (RBV), and combines this with internationalisation theory. The setting of SMEs is a context for using the RBV. New Zealand and Australian exporting SMEs provide the sample for testing the hypotheses. The contributions of this thesis are twofold. Firstly, the thesis identifies four determinants of forex risk strategy by exporting SMEs, i.e. degree of internationalisation (specifically, export ratio), forex exposure, perceived forex risk, and resources. Secondly, it extends the use of the RBV and the internationalisation theory in forex risk management of SMEs. In addition, the thesis uses a research approach combining an exploratory qualitative study and a main quantitative study.

View record details
• ### Self-improvement books: A genre analysis

#### Koay, Dong Liang (2015)

Doctoral thesis
Victoria University of Wellington

View record details
• ### A Critical Realist Study of Political Identity in Aotearoa New Zealand: Materiality, Discourse and Context

#### Woodhams, Jay (2015)

Doctoral thesis
Victoria University of Wellington

Political identity is a complex phenomenon that is generated within a rich sociocultural context. This thesis examines political identity in informal talk which is situated within a relatively under-explored context, New Zealand’s capital city and political centre, Wellington. Grounding the study within the critical realist model of stratified reality provides the philosophical motivation to explore multi-layered discourses alongside the extra-discursive referents that underpin them. The analysis centres on a model of identity, contra postmodernism, which shows that identities, while socially recognised in discourse, are articulated in reference to physical and social structures. I adopt a comprehensive multi-layered approach to discourse by examining the macro sociocultural influences that appear to pattern interaction across the country, the meso-level subnational discourses that influence dialogue at a more situated level and the micro-level interactional stances taken up in everyday communication. Discourse at all levels is implicated in the identities I examine in this thesis and it is against this backdrop that I unpack political identity into its indexed discourses and constitutive stance acts. Framed by my ethnographic immersion in the study context and drawing on in-depth semi-structured interviews with twenty-six individuals, I explore the way in which discourse and stancetaking are implicated in the genesis of the participants’ political selves. I first consider the extra-discursive context, including the geographical, economic and cultural structures that underlie New Zealand discourses. This is followed by detailed analysis of sociocultural discourse as it appears in talk. I identify egalitarianism and tall poppy as two related discourses which are embedded within the historical context of the country. I also explore four subnational discourses relating to Wellington city, including the political town, left-wing and small town discourses, which occur alongside a discourse of contrast. These sociocultural and subnational discourses influence much of the talk that occurs in reference to politics in Wellington and are thus implicated in political identity as it is generated in moment-by-moment interaction. To explore this in further detail I examine the micro-level of interactional discourse, more specifically the processes of stancetaking, in two detailed case studies. The two focus participants demonstrate prominent stance processes which I argue are central to much identity work: intersubjectivity, in which the stances of all those involved in the discussion interact in complex ways; and multiplicity, when participants take numerous stance directions that appear to contribute to different aspects of their identities. The intensive focus on the case studies, alongside analysis of the full discursive and extra-discursive context, provides a multi-layered and philosophically anchored approach that seeks to contribute to current understandings of and approaches to the study of discourse and identity.

View record details
• ### First Principles Study of Ga₍₂₀₋x₎Alx⁺ Nanoalloys: Structure, Thermodynamics and Phase Diagram

#### Ojha, Udbhav (2015)

Doctoral thesis
Victoria University of Wellington

Nanoalloys (a finite framework of two or more metal atoms) represent a rapidly growing field owing to the possibilities of tuning its properties as desired for various applications. Their properties are size, shape, composition, chemical ordering, and temperature dependent, thereby offering a large playground for varied research motivations. This thesis documents the investigations on how the addition of aluminium affects the cationic gallium clusters, both in terms of geometric & electronic structure and thermodynamics, which have been observed to show greater-than-bulk melting behaviour for small sizes. A specific cluster size of 20 atoms is selected, Ga₍₂₀₋x₎Alx⁺, with the overall intention of creating a phase diagram which is the most reliable way to predict the phase changes in the system. All the first principles (density functional theory) based Born-Oppenheimer molecular dynamics calculations have been performed in the microcanonical ensemble. Melting behaviour is first studied in the pure Al₂₀⁺ clusters and then in three representative clusters of Ga₍₂₀₋x₎Alx⁺ series: Ga₁₉Al⁺, Ga₁₁Al₉⁺ and Ga₃Al₁₇⁺ clusters. We observe that all the three nanoalloy compositions show greater-than-bulk melting behaviour behaviour as well and in Ga₁₉Al⁺, specifically, Al prefers the internal sites, contrary to the previous arguments. We go on to complete the solid-liquid-like melting phase diagram using the calculated information and further propose a model of these greater-than-bulk melting clusters to be components of the corresponding bulk phases, whether metals or alloys, with additional size-dependent contributions added to it.

View record details
• ### Human inspired robotic path planning and heterogeneous robotic mapping

#### Williams, Henry (2016)

Doctoral thesis
Victoria University of Wellington

View record details
• ### Evaluating the Influence of Governance on the Built form: The Redevelopment of Wellington, New Zealand’s Waterfront Precinct

#### O'Byrne, Colin (2016)

Doctoral thesis
Victoria University of Wellington

Because there are many ways of structuring and managing a land development process, this research asks the question: What influence do different decision making approaches have on the built form of the Wellington waterfront redevelopment? The form of the built environment is shaped by existing physical and economic conditions; the values of those involved in the planning and design of it; and, the activities of those who occupy it. However, the social structure and mechanisms of decision making (i.e. the governance) within the urban planning and design stages of the development process act as a filter for identifying and prioritizing factors that will have the greatest influence on the form. Because of the filter effect, this thesis argues the governance of a development process has observable effects on the built form of the associated development project. A review of urban design, urban morphology, and land development literature identified related research on the governance-built form relationship. Studies in urban design and development processes have generally identified single, overall governance approaches for development projects and have not effectively identified relationships with the built form. Recent work in the field of urban morphology has more effectively identified relationships between governance practices and the evolution of the built environment; however, these studies have tended to treat governance as a single process rather than a sequence of different governance approaches. Therefore, this study examined the redevelopment of the Wellington waterfront to look for and identify the different governance approaches that were used over the study period and how these influenced the resulting built form. To address the question of what effect different governance approaches had on the built form, the history of the redevelopment was analyzed in depth. Through analysis of written records, semi-structured interviews with participants involved in a variety of redevelopment related roles, and site visits, it was possible to characterize different governance approaches within the overall project and how these have influenced the form of the built environment. Triangulation of the three methods was used to provide a richer description of the redevelopment and improve confidence in the findings. Between 1974 and 2012, Wellington transitioned through seven separate governance approaches, each having some influence on the form of the redevelopment. Each governance approach was marked by different driving values and forms of stakeholder involvement that affected the redevelopment. For example, periods dominated by top-down or corporate approaches resulted in larger and more internally focused buildings and building sites than periods with more inclusive governance arrangements. Characterizing the governance approaches and their effects on the built form provided a useful tool for evaluating and understanding the development process and the evolution of the built form of the Wellington waterfront. This level of understanding of the different governance approaches and their influence on the built form has not been previously described in the literature. While the findings cannot be assumed to be descriptive of other development projects, they do identify patterns that should be investigated in other development contexts. The approach and findings from this thesis therefore contribute to the literature on the relationship between the processes and products of urban design, and the social structures of development processes.

View record details
• ### Spectroscopic investigation of excitonic and charge photogeneration processes in organic photovoltaic cells

#### Gallaher, Joseph (2016)

Doctoral thesis
Victoria University of Wellington

Organic photovoltaic (OPV) cells show significant promise as a renewable energy resource capable of meeting the world’s large and growing energy needs. Increasing device efficiency is central to achieving an economically viable option for widespread applications. To this end, a better understanding of the structure and dynamics of the electronic excited states is needed. In particular, the mechanism by which excitons (electron-hole pairs) escape their Coulombic attraction and generate photocurrent is yet to be established. In this thesis ultrafast laser spectroscopy, in particular transient absorption and time-resolved photoluminescence, are used to study: exciton relaxation, morphological effects on charge separation, and the pathway leading to triplet exciton states. In Chapter 3, a series of oligothiophenes are synthesised with well-defined conjugation lengths to act as molecular models of polymer backbone sub-units, and thereby probe exciton relaxation processes. Time-resolved photoluminescence (TRPL) and transient absorption (TA) spectroscopy measurements presented in Chapter 4 reveal emission signatures evolve from a mirror image of absorption - which lacks vibronic structure - towards a spectrally narrower and vibronically structured species on the hundreds of femtosecond to early picosecond timescale. Analysis of this spectral evolution shows that a broad distribution of torsional conformers is driven to rapidly planarize in the excited state, including in solid films. This provides evidence that both torsional relaxation and energy migration could contribute to the non-mirror image absorption-emission spectra observed in polymer thin films. Recently, long lived TA signatures have been attributed to triplet excited states with the suggested formation pathway being similar to organic light emitting diodes, whereby non-geminate (bimolecular) charge recombination leads to the formation of both singlet and triplet states. Isolated oligothiophenes in solution provide an ideal model system to investigate the role of structural relaxation on triplet exciton formation. Through analysis of TA spectral dynamics in Chapter 5, singlet and triplet exciton populations were tracked. Restriction of the torsional relaxation increased triplet yield suggesting vibrational hot states could drive triplet formation. This model could aid in understanding triplet exciton formation in polymer-based solar cells via spin-mixing instead of non-geminate recombination. In a series of polymer:fullerene blends, the link between the nature of polymerfullerene intermixing and charge generation pathways was investigated. It is shown in Chapter 6 that free charge generation is most efficient in a 3-phase morphology that features intimately mixed polymer:fullerene regions amongst neat polymer and fullerene phases. Distinct spectroscopic signatures made it possible to determine whether holes occupy disordered or crystalline polymer chains. TA spectral dynamics reveal the migration of holes from intermixed to pure olymer regions in 3-phase morphology blends, which contrasted with observations in 2-phase blends. The energy gradient between the intermixed and phase-pure regions may be sufficient to drive efficient separation of charge pairs initially generated in intermixed regions, with free charges subsequently percolating through these phase-pure domains. The photophysics of a high performance polymer:polymer blend is studied in Chapter 7 in an effort to elucidate how these blends can rival their polymer:fullerene counterparts. Optical spectroscopy reveals incomplete exciton dissociation and rapid geminate recombination in the blends. This is shown to result from a largely phase-separated morphology with domains greater than the exciton diffusion length. Significant loss of charge carriers on early timescales highlights increasing polymer: polymer solar cell efficiency requires optimizing blend morphology to realise facile charge separation. Taken together, this thesis presents a valuable spectroscopic insight into the pathway of efficient charge separation and the importance of both blend morphology and polymer structure.

View record details
• ### Seismic investigations of the lithosphere in an amagmatic back-arc region: North Island, New Zealand

#### Dimech, Jesse-Lee (2016)

Doctoral thesis
Victoria University of Wellington

New seismic constraints on crustal and upper mantle structures, kinematics, and lithospheric rheology are reported from an amagmatic back-arc region: the southwest North Island of New Zealand. Robust earthquake locations reveal a hypocentre 'downwarp' beneath the east-west trending Taranaki–Ruapehu Line. These earthquakes occur in the uppermost mantle, at depths of 30–50 km, and are distinct from shallower 8–25 km-deep earthquakes near Mt. Ruapehu in terms of focal mechanisms and principal stress directions. A receiver function CCP stack shows that the mantle earthquakes occur beneath a large change in crustal thickness, where the Moho 'steps' from 28 to 35 km-deep and the steepest part of that step has a 20–50° dip. The mantle earthquakes are dominated by strike-slip fault movement and have a maximum compressive stress direction of NE–SW. The existence of mantle earthquakes beneath a steeply-dipping Moho step implies some sort of dynamic modication is occurring in the mantle lithosphere. One possibility to explain these features is the convective removal of the mantle lithosphere due to a Rayleigh–Taylor-type instability. South of the Taranaki–Ruapehu Line, the Moho conversion weakens on both the receiver function CCP stack, and marine seismic reflection data under most of the Wanganui Basin (SAHKE02 and GD100 seismic lines). However, localised bright reflections at Moho depths can be seen in both near-vertical and wide-angle seismic data. Attribute analysis of near-vertical seismic reflections suggests that the rocks beneath the reflectivity are strongly-attenuating (Q ~20) with a negative velocity contrast relative to the lower crust. These observations are interpreted to be related to the presence of serpentinite (antigorite) and/or high pore fluid pressures in the mantle wedge. The links between hydration of amagmatic back-arcs, serpentinisation and/or high pore fluid pressures, rock viscosity, and mantle instabilities are documented here for the southwest North Island of New Zealand. These associations may be applicable to other amagmatic back-arcs around the world.

View record details
• ### Directing: A Mirror to Solo Performance Provocation, Collaboration and Proxy Audience

#### Richards, Sally (2016)

Doctoral thesis
Victoria University of Wellington

Solo performance is a challenging, immediate and exhilarating form of theatre. Its popularity in the field of westernised contemporary theatre is evidenced in the increasing programming of solo performances at international festivals and in commercial theatres. However, whilst there is considerable analysis of the genre of solo performance there is little examination of the relationship between director and solo performer in the rehearsal room. Prior research has focused on the theoretical or on the practical, but rarely have the two approaches actively engaged with each other. This thesis contributes a much-needed analysis of directing practice in this area, and an integration of theory and practice that offers tangible approaches in the rehearsal room. In what ways can the director best serve the solo performer to create a theatrical experience that can hold the audience's attention, imagination and memory? Solo performance is characterised by a heightened presence in both performer and audience, incited by a minimalism that abandons the theatrical premise of artifice and turns to primary storytelling. The rehearsal room relationship between director and solo performer also shares these qualities, heightened and focused by the one-one engagements. Directing in this context contrasts from that of a multi-cast, with distinctly different dynamics arising from an artistic collaboration between two people, rather than with many. This thesis considers how the director is placed as a flexible paradigm as proxy audience and as a bidirectional-mirroring device in the rehearsal process – situating the director as an articulated reflection to the transforming solo performer. I analyse this unique partnership and focus primarily on strategies that directors use to create effective solo performance. This thesis is comprised of 80% critical writing and 20% for the creative/practice-based research project. I examine the particular qualities of solo performance as a genre; its theatrical origins, function and purpose, the scope of styles and forms and its potential for political and social meaning. However, my focus is on the rehearsal room processes, working predominantly with a director, rather than an analysis of the end product - the performance. I interview practitioners in the field about their rehearsal room experiences, across the spectrum of styles and forms of solo performance. My theoretical framework is centred on Practice as Research (PaR). In order to scrutinise the relationship between director and solo performer I have gained access to the rehearsal room as both director/practitioner and researcher. The PaR component of this thesis includes the analysis of the experimental rehearsal process and performance of PocaHAUNTus - a new autobiographical solo play. In addition I draw on a body of retrospective work – re-examining my direction of five solo performances that occurred prior to this thesis. Production journals, rehearsal and performance footage, interviews, communications and photographs evidence all components. My research question is not simply “Does a solo performer need a director?” Instead, my research pursues how the relationship between the two might be negotiated, asking: “In what ways can the director best serve the solo performer?” The research examines the fundamental challenges of the genre, namely: the delineation of multiple characters by a single performer, immediacy of the audience relationship to the lone performer, stage geography and scenographic choices. The research also identifies and refines practical strategies to accommodate the intensity of working one-on-one. At its best, the director-solo performer relationship is a vibrant and supportive partnership but because of its intimacy, it is often also a complex and challenging engagement. The contribution of this thesis and its originality is in a PaR model that utilises my past experience of directing solo performance, expands on this foundation through the collection of extensive interview material from a diverse range of significant directors and performers of solo work, and then pursues a new creative laboratory where I test key approaches to directing solo performance.

View record details
• ### Essays on Disaster Risk and Economic Development

#### Karim, Azreen (2016)

Doctoral thesis
Victoria University of Wellington

This thesis consists of four self-contained papers in the areas of disaster risk and economic development. Chapter One provides a qualitative survey of the empirical literature on the nexus among poverty, inequality and natural disasters. The last few years have seen an explosion of economic research on the consequences of natural disasters. This new interest is attributable first and foremost to a growing awareness of the potentially catastrophic nature of these events, but also a result of the increasing awareness that natural disasters are social and economic events. Here, we survey the literature that examines the direct and indirect impact of natural disaster events specifically on the poor and their impact on the distribution of income within affected communities and societies. With a meta-regression analysis of the existing literature on the impacts of disasters on households in Chapter Two, we observe several general patterns. Incomes are clearly impacted adversely, with the impact observed specifically in per-capita measures. Consumption is also reduced, but to a lesser extent than incomes. Poor households appear to smooth their food consumption by reducing the consumption of non-food items; in particular health and education, and this suggests potentially long-term adverse consequences. Given the limits of our methodology and the paucity of research, we find no consistent patterns in long-term outcomes. We place disaster risk to the poor within the context of sustainable development and future climatic change. Our objective In Chapter Three is to identify all of the directly observable determinants’ of publicly allocated and realized spending for disaster risk reduction (DRR) at the local government (sub-district) level in Bangladesh. We employ the Heckman two-stage selection model with detailed public finance and other data from 483 sub-districts (Upazilas) across the country. While some of our results conform with our priors, our estimations surprisingly find that government does not respond to the sub-district’s risk exposure as a factor affecting the DRR financing mechanism. This variable is consistently counter-intuitively statistically insignificant. The DRR regional allocations do not seem to be determined by risk and exposure, only weakly by vulnerability, nor even by more transparent political economy motivations. In Chapter Four, we examine the short-run economic impacts of recurrent flooding on Bangladeshi households surveyed in 2000, 2005 and 2010. In 2010 Household Income and Expenditure Survey (HIES), households answered a set of questions’ on whether they were affected by flood and its likely impacts. We identify two treatment (affected) groups by using the self-reported data and historical rainfall data based flood risk index. We estimate a difference-in-difference (DID) model to quantify the impacts on income, expenditure, asset and labour market outcomes and further extend our analysis to different income and expenditure brackets. Overall, we find robust evidence of negative impacts on agricultural income and expenditure. Intriguingly, the extreme poor (i.e. the bottom 15th quintile) experience significant positive impacts on agricultural income in the self-reported treatment case.

View record details
• ### An Archaeomagnetic Study of Hangi Stones in New Zealand

#### Kinger, Rimpy (2017)

Doctoral thesis
Victoria University of Wellington