27,544 results for ResearchSpace@Auckland

  • Slow Manifolds, Canard Orbits and the Organization of Mixed-Mode Oscillations

    Hasan, Ragheb (2017)

    Doctoral thesis
    The University of Auckland Library

    A mixed-mode oscillation is a complex waveform with a pattern of alternating smallamplitude oscillations (SAOs) and large-amplitude oscillations (LAOs). MMOs have been observed in many applications, including semiconductor lasers, neuron models and chemical reactions. In this thesis, we aim to understand and elucidate the phenomenological behavior of MMOs inherited in slow-fast systems, which take the form of ordinary differential equations with a group of fast variables and a group of slow variables, with a time-scale separation parameter ". Geometric singular perturbation theory predicts the existence of locally invariant slow manifolds that organize the slow dynamics. The fast dynamics are typically organized by stable and unstable (fast) manifolds of slow manifolds. Interactions of slow manifolds give rise to so-called canard orbits, which create a mechanism for generating SAOs. On the other hand, LAOs require a global return mechanism. In this thesis, we present a framework for studying two-dimensional slow manifolds, canard orbits and their roles in organizing MMOs in parameter regimes where " is too large for applying classical results from the theory. This is achieved by employing advanced numerical methods based on a two-point boundary value problem setup. We first consider an autocatalytic chemical reaction model with one fast and two slow variables. In this system, we find that canard orbits, which occur along intersections of two-dimensional attracting and repelling slow manifolds, are organized in pairs that we call twin canard orbits. Consequently, the extended attracting slow manifold is divided into subsurfaces called ribbons. Ribbons and associated twin canard orbits organize MMOs when " is relatively large. A continuation analysis illustrates how twin canard orbits arise due to generic quadratic tangencies of slow manifolds. In systems with two fast and two slow variables, two-dimensional slow manifolds of saddle type play a key role in organizing MMOs. One goal of this thesis is to introduce a general approach for computing two-dimensional saddle slow manifolds and their threedimensional stable and unstable manifolds, as well as associated canard orbits in R4. We first test and demonstrate our methods for an extended normal form of a folded node. These methods are then reliably implemented for the full four-dimensional Hodgkin- Huxley neuron model, where " is again relatively large. Our results show that MMOs of this model are also organized by ribbons of the attracting slow manifold and bounding twin canard orbits. Overall, we conclude that our approach is suitable for computing two-dimensional slow manifolds in R3 as well as in R4, and in parameter regimes that are beyond what is known from established theory. In particular, we show that it is practical to study fourdimensional slow-fast vector fields without the need for applying any reduction technique.

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  • Finding ourselves: New Zealand theatre's overseas experience

    Wenley, James (2018)

    Doctoral thesis
    The University of Auckland Library

    Throughout Aotearoa/New Zealand???s dramatic history, there has been a strong impulse for plays from this country to be toured and performed overseas, despite the considerable financial and geographical challenges posed. The colloquial expression OE (Overseas Experience) marks the importance of this desire, in which it is only by leaving home that the New Zealander realises their identity. The Overseas Experience of New Zealand theatre has been an overlooked aspect in scholarship. This thesis investigates how the meaning of a New Zealand theatre work might operate in a specific time, place, and moment. It is the first to consider connections between a range of New Zealand productions overseas, including touring works, and works that non-local companies have chosen to perform. The study attempts to balance breadth ??? giving an account of overseas performances of New Zealand work primarily from 1941-2016 ??? with depth, making extensive use of archival research to analyse in detail significant moments in New Zealand theatre???s OE. From these selected case studies, it builds a larger argument, drawing on concepts such as post-colonialism, transnationalism, and globalisation, to understand the wider development and reception of New Zealand theatre???s OE. Theatre is a site where issues of national identity can be raised. The core of this thesis is how New Zealand national identity is performed through drama, and how this identity is read by audiences around the world. This work demonstrates how the OE has been driven by anxieties around constructing a unique New Zealand identity through the theatre, and gaining legitimacy for this represented identity through overseas approval. This study engages with the whole theatrical enterprise as a play travels from concept and scripting through to funding, marketing, performance, and the critical response by reviewers and commentators. These findings are of global interest to academics, producers, and theatre artists as a significant resource for theatre touring and practice.

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  • Circles of Support and Accountability: An Investigation of Volunteer Motivation and Experiences, and the Effect of the ???Sex Offender??? Label on Community Attitudes Towards Individuals who have Sexually Offended

    Lowe, Giulia (2017)

    Doctoral thesis
    The University of Auckland Library

    The importance of social support in the rehabilitation and reintegration of individuals convicted for sexual offences is undisputed; however, few community members are accepting of these individuals living in their communities, let alone having regular contact with them. Circles of Support and Accountability (CoSA) is a promising reintegration framework whereby community volunteers support individuals convicted for sexual offences to reintegrate safely into the community (R. J. Wilson & Prinzo, 2002). The current research utilised a mixed method approach to investigate volunteers??? motivation to join CoSA, their experiences of volunteering with CoSA, and the effect of the ???sex offender??? label on community attitudes and willingness to volunteer with CoSA. Part One of the current research included three studies that utilised in-depth semi-structure interviews. Study One (N = 18) investigated volunteers??? motivation to be involved with CoSA. Three key motivations were identified: (i) Restorative and Justice Based Motivation, (ii) Altruistic Motivation, and (iii) Faith Based Motivation. Study Two (N = 18) explored volunteers??? experiences of CoSA, including general experiences and how some volunteers coped with their core member being recalled or reoffending. Findings illustrated how volunteers balanced risk management with providing social support, questioned the place of religion in CoSA, and confronted stereotypes surrounding individuals who have sexually abused. In the event of a core member being recalled or reoffending, findings revealed both the volunteers??? commitment to CoSA and their core member, and the negative impact on volunteers. Study Three (N = 23) explored volunteers??? experiences of training and support, and their perceptions of what contributed to effective circle functioning. Findings highlighted a mixed response to the training and support received, and that identifying suitable core members and volunteers, clear communication, establishing boundaries between circle members, and the presence of an external circle coordinator contributed to effective circle functioning. Part Two of the current research comprised of one study, Study Four, that examined the effect of the ???sex offender??? label on attitudes and willingness to volunteer with people who have sexually offended, utilising a general community sample (N = 391). Study Four additionally investigated priming effects of labelling versus neutral language on participants own language use. Participants were randomly assigned to either a label condition or a neutral condition and completed an anonymous online survey. The labelling condition utilised labels (e.g., ???sex offender???) while the control condition utilised neutral descriptors (e.g., ???people who have committed crimes of a sexual nature???). Findings from this study showed that the use of the ???sex offender??? label was associated with more negative attitudes as measured by the Community Attitudes toward Sex Offenders scale (Church, Wakeman, Miller, Clements, & Sun, 2008), less willingness to volunteer with people who have sexually offended, and primed the voluntary use of labels. Together, findings from the present research advance our understanding of why some people choose to volunteer with a stigmatised population, and the everyday experiences of CoSA volunteers. Moreover, findings offer important insights into how we can promote attitudes that support safe reintegration practices. Preventing reoffending is a core community concern, therefore it is important to find ways of engaging with communities to promote a safe reintegration, and ultimately, desistance from offending.

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  • A Framework for Understanding and Evaluating the Quality of Data Sets in Empirical Software Engineering

    Mohd Rosli, MB (2018)

    Doctoral thesis
    The University of Auckland Library

    Software engineering data sets provide valuable information related to software development and the evolution of software projects. Researchers often obtain software engineering data sets from public data repositories, which contain data and metadata about software development artefacts, such as the bug reports and source code. Typically, the term data refers to measurements associated with metrics and entities, whereas the term metadata describes the meaning and context of the data. However, there is growing concern regarding the quality of such data sets because they can lead to questionable empirical results if the data is of poor quality. Researchers, who are the creators of data sets, describe the data and metadata in many different ways. This creates challenges that make it difficult to interpret data sets or to report clearly the quality of data. Moreover, researchers intending to use data sets from public data repositories rely on their quality. Although many techniques have been proposed in the literature to resolve the challenges associated with data quality, there is a lack of research that evaluates the quality of data sets in public data repositories. The main research question in this study is, 'How can we help researchers to understand the quality of data sets in software engineering?' Hence, the aim of the study was to develop a data quality assessment framework to interpret the data sets better and evaluate their quality. The framework will allow researchers to understand the quality of data and identify any potential problems that may be present in a data set. The research was organised into six steps. The first step was a review of data quality in software engineering. The results of a systematic mapping study carried out as part of the review showed that many definitions of data quality issues are unclear because of the inconsistent terminology used in these definitions. The second step was an observation of existing and artificial data sets to explore their different formats and structures. The results from the observation of data sets indicated that few data sets contain metadata to describe what the data mean, which might lead to misinterpretation. The third step was designing a metamodel to describe the structure and concepts associated with data sets, and the relationships between each concept. Every concept in the metamodel is defined using standard terminology to allow common interpretation of data. The fourth step involved developing a framework for data quality assessment to determine whether a data set contains sufficient information to facilitate the correct interpretation of data. The fifth step was constructing formal guidelines for the creation of good-quality data sets. The guidelines were constructed based on the essential terminology of the dataset metamodel and procedures from the framework. The final step consisted of the evaluation of part of the framework by means of a user study. The part of the framework consists of definitions of elements in the dataset metamodel and formal definitions for data quality issues. The research makes four significant contributions which are: (i) a systematic mapping study on data quality in software engineering. (ii) a dataset metamodel for describing the structure of data sets. (iii) a data quality assessment framework to better understand the quality of data sets. (iv) formal guidelines for creating good-quality data sets.

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  • Green Spaces and Health: Evidence from Growing Up in New Zealand

    Nichani, Vikram (2018)

    Doctoral thesis
    The University of Auckland Library

    Background and Aims: Exposure to green space has been linked to increased physical activity and a lower likelihood of antenatal depression amongst pregnant women. However, it is not clear whether this is because active people prefer to live in greener areas, that is, whether these findings are a result of ???self-selection??? bias. For the child, exposure to green space during the mother???s pregnancy has been found to be associated with increased birth weight and gestational age, two important determinants of health in early childhood. However, limited data exist on the effect modifications of the relationship of exposure to green space during pregnancy with birth weight and gestational age that are due to age, self-identified ethnicity, education, residential rurality, and the socioeconomic status of the pregnant women. There are also limited data that specifically relate to pregnancy, and which investigate the relationship between exposure to green space during pregnancy and antenatal depression whilst also taking onto consideration maternal age, self-identified ethnicity, education, physical activity, residential rurality, and the socioeconomic status of the pregnant women. In this study, I examined whether exposure to green space for pregnant women was independently associated with their increased participation in physical activity and with a decreased likelihood of them reporting antenatal depression, and with an increase in birth weight and gestational age in their new born infants. My analyses accounted for selfselection bias of residential locality. Effect modifications for birth weight and gestational age were investigated after stratifying for age, education, self-identified ethnicity, residential rurality, and socioeconomic status. Additionally, effect modifications for antenatal depression were explored after stratifying for these same factors, as well as for level of physical activity. Methods:My study utilised the Growing Up in New Zealand cohort study antenatal dataset and the perinatal data of the pregnant women recruited into this study. My study consisted of three main components which respectively investigated: 1) Green space and physical activity in pregnant women; 2) Green space and pregnancy outcomes in pregnant women; and 3) Green space and depression in pregnant women. The data for estimating green space were obtained from the local City Councils and the New Zealand Land Cover Database. Exposure to green space was assessed by geocoding residential addresses and further estimating the proportion of green space in each census area unit within the Auckland, Counties-Manukau and Waikato District Health Board regions of New Zealand, where pregnant women had to reside in order to be eligible for enrolment into the Growing Up in New Zealand cohort. Health data for the pregnant women were obtained from the Growing Up in New Zealand antenatal dataset; and the birth data for the new born infants were obtained through the perinatal data assembled from various sources that was linked to the Growing Up in New Zealand antenatal dataset. The short version of the International Physical Activity Questionnaire was utilised for estimating physical activity at two-time periods during pregnancy: during the first trimester and during the remainder of pregnancy. Assessment of antenatal depression was through the administration of the Edinburgh Postnatal Depression Scale Questionnaire. Exploration of the associations of green space with physical activity and with antenatal depression were completed using multilevel mixed logistic regression models, while the associations between green space with birth weight and gestational age were completed using multilevel mixed linear regression models. Results: Exposure to green space for the entire cohort was not associated with participation in physical activity during the first trimester or the remainder of pregnancy after accounting for self-selection bias. Exposure to green space was not associated with birth weight or gestational age for the entire cohort. However, exposure to green space was associated with gestational age for pregnant women residing in rural areas. Exposure to green space during pregnancy was not associated with the odds of antenatal depression after accounting for self-selection bias, nor was there any evidence of effect modifications for specific population subgroups. Conclusions: Results suggest that exposure to green space is not associated with participation in physical activity, once preference for living in greener neighbourhoods is taken into account. While exposure to green space was not found to play a role in improving birth weight and gestational age when considering the entire cohort, it was found to be associated with a more mature gestational age for pregnant women residing in rural areas. Exposure to green space during pregnancy was found to not be associated with the odds of a women experiencing depression when considering the entire cohort, nor for any specific subgroups. It can be assumed that the availability of green space is not an important determinant of pregnancy and child health for the entire pregnant population in the cohort, but it is for pregnant women residing in rural areas. However, considering the limitations of the studies, the lack of associations between green space and health outcomes (physical activity, birth weight, gestational age, and depression in this case) for the cohort as a whole does not mean that green space will not affect their outcomes. My findings highlight the importance of considering self-selection bias and accounted for this when investigating relationships between green space and health outcomes in pregnant women and their new born infants. More studies are warranted on green space and maternal and child health outcomes in similar or different contexts overcoming these limitations.

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  • Characterising and Modifying the Keratoconus Disease Process in New Zealand ??? The Aotearoa Research into Keratoconus (ARK) Project

    Gokul, Akilesh (2017)

    Doctoral thesis
    The University of Auckland Library

    This thesis contains six inter-related investigations aimed at improving the understanding of the epidemiology, clinical characteristics and natural history of keratoconus in New Zealand (NZ) and to investigated the safety and efficacy of two novel high intensity, high irradiance accelerated corneal collagen cross-linking (A-CXL) protocols. The project was titled the Aotearoa*1 Research into Keratoconus (ARK) Project. The ARK Study: Part I investigated the epidemiology and basic clinical characteristics of subjects with keratoconus managed by optometrists in NZ. The results of ARK Part I possibly confirm the long held clinical suspicion that keratoconus has an ethnic predisposition for M ori and Pacific Peoples individuals. Furthermore, the results suggest that keratoconus is potentially more severe among The ARK Studies: Part IIA, B and C, investigated the phenotypic clinical characteristics and natural history of keratoconus in NZ utilising both prospective and retrospective designs. ARK Part IIA, indicated that keratoconus may have a greater inter-eye disease asymmetry in NZ and that corneal tomographic features/disease severity are correlated with corneal microstructure and biomechanical integrity. ARK Part IIB and C suggest that keratoconus may continue to progress beyond age 30 years and ARK Part IIB characterised the relationship between corneal curvature/power and contact lens corrected visual acuity. The ARK Study: Part IIIA focused on the repeatability and comparability of corneal curvature/power and pachymetry in three commonly used corneal tomographers in keratoconic eyes and revealed that; corneal curvature/power was most repeatable on the Pentacam HR while pachymetry was most repeatable on the Galilei G2 and the Orbscan II was least repeatable for all parameters, however all measured parameters cannot be used inter-changeably between the three devices. ARK Part IIIB investigated two novel A-CXL protocols utilising continuous and pulsed high irradiance, high intensity ultraviolet-A irradiation and demonstrated that both are safe and effective at slowing or halting the progression of keratoconus 12-months post-operatively. The results of the inter-related investigations that form the ARK project provide new data on the epidemiology, clinical characteristics and natural history of keratoconus in NZ and the safety and efficacy of two novel A-CXL protocols.

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  • Rhythmic Affectensities Becoming-New: An Ethics of Expression for Early Childhood Education

    Hargraves, Victoria (2017)

    Doctoral thesis
    The University of Auckland Library

    Moving beyond the reproduction of static forms and rigidity in thought, action, and institutions in education, ethical becomings require the engagement of an expansion and intensification of a body???s affect or capacity. Ethics, thought with the immanent materialist philosophy of Deleuze (1969/1990, 1968/1994) and Deleuze and Guattari (1972/1983, 1980/1987, 1991/1994), can provoke and promote a creativity of becoming through the entanglement of a posthumanist univocity. Intending to provoke heightened ethical capacities, a posthumanist orientation opens up potential connections available to diverse bodies, with which to enact multiple becomings-new. Some of this potential is performed in this thesis. The text explores a series of imagined trajectories of becoming, pursuing and attending to transformative movements, for entities as diverse as clay, table, and highchair; concepts such as expression, monster, and intensity; and fictional and conceptual personas including teacher, child, Deleuze, Guattari, and Piaget. This is a becoming-thesis which accumulates affirmative relations of mutual affect and constitution across a range of elements and forces (Braidotti, 2016). Alongside the matters of early childhood education, the thesis deploys, then interrupts and experiments with, various aspects of methodology-matter (researcher, ethics, data, code, and method), contributing to postqualitative directions in methodology. With objects, bodies, and thinking all seen as expressions of matter???s interrelations, the thesis thinks into the relationship and affect of language with and as matter, challenging the centrality of linguistic representations in human interaction with, and manipulation of, matter. By challenging the recognition and representation of matter which is so dominant in education, the thesis unsettles claims to know, label, and define the potential of human and nonhuman matter. The thesis explores affectensity, a term coined to describe particular intensities of affect, in order to undo habitual relations and meanings. Playing with sense and affect, rather than working through and reproducing established and assumed orders of knowing, gives rise to an experimental assemblage that invites reconfiguration in a becoming-ethical of the expressions of subjects, things, and matter in early childhood education, and in becoming-thesis. An ethics of diversifying and transforming expressive lines enables a constant individuation for thesis, and early childhood education, always becoming-new.

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  • The Emotional Psychologist: A Critical Discursive Analysis of Psychologists??? Talk about Their Emotions within the Therapeutic Relationship

    Van Der Merwe, Helen (2017)

    Doctoral thesis
    The University of Auckland Library

    While psychologists??? own emotional management is an integral part of psychological therapy, it is often assumed rather than discussed; the affective expectations for the profession are unarticulated. In this research I explore how psychologists talk about their patterns of emoting within the therapeutic relationship in order create an account of the profession???s expectations for emotional expression and to open up a space for a critical examination of these expectations. I understand emotion as affective practices which are both being constituted actively as people carry out the practice and shaped over time as past practice carves out grooves of emoting that become familiar and habitual (Wetherell, 2012). This understanding of emotions attends to both patterns, and points of tension or contestation. I asked practising psychologists about their emotional practices within the therapeutic relationship in four small focus groups and 11 follow up individual interviews. I use the variety of discourse analysis developed within critical social psychology (Billig, 1987; Edley, 2001; Wetherell, 1998) to examine how participants made meaning around their emotions within the therapeutic relationship by drawing on different affective-discursive repertoires. The analysis includes an account of how psychologists have come to construct their emotions in dilemmatic ways in the context of clinical psychology as a profession (which has gone through many iterations in the years since its inception in the first part of the 20th century), and well as a consideration of how participants spoke about trying to resolve these points of tension and dilemma. I also consider participants??? talk about when professional feelings go awry, how they work on themselves in order manage ???unprofessional??? emotions, and the implications of these affective-discursive identity negotiations for their constructions of self. I suggest that that the exchange of certain emotions for remuneration within this profession becomes hidden within the individuals??? subjectivity. I consider some of the wider social power relations that both hold these practices in place and are reproduced as psychologists emote in prescribed ways. Finally I reflect on whether an affective practices understanding of emotions could be used as a rhetorical tool to help psychologists look more critically at the functions of their emotions within the therapeutic relationship.

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  • Quantum Transport Experiments with Ultracold Atoms

    White, Donald (2016)

    Doctoral thesis
    The University of Auckland Library

    Quantum simulation is a burgeoning field of research, in which quantum systems are engineered to behave similarly to external, complex systems of interest. These quantum simulators are an alternative to the elusive all-purpose ???quantum computer??? and instead function as analogue computers, allowing an external system of choice to be understood via measurements on a controllable engineered system. An important practical aspect of quantum mechanics concerns its effects on transport. This thesis describes a series of experiments with ultracold atoms in custom optical potentials, detailing quantum simulators developed for analysing the quantum transport properties of specific systems of interest. Two environments in particular are investigated: the quantum chaotic system of the deltakicked rotor, and a spatially disordered potential. The delta-kicked rotor investigations focus on the effects of phase modulation. By applying a periodic phase modulation of f0; 2 =3; 0g, the phase space is modified to generate a Hamiltonian ratchet, manifesting as directed transport within the chaotic sea without any biased force. We characterise the phase space by applying -classical theory, and capitalise on the narrow momentum distribution of a Bose???Einstein condensate by experimentally exploring the phase space. A sinusoidal phase modulation reveals two different transport regimes, dependent on the commensurability of the kicking frequency and phase modulation frequencies. We characterise the resonances found in the commensurate case, and study the effective phase noise induced in the incommensurate case. A particular finding of this investigation is that the quantum resonance is relatively robust to phase noise, while dynamical localisation is inhibited by small levels of phase noise. Finally, we implement a truly custom potential with high resolution imaging of a spatial light modulator, and develop a unique high aspect ratio 2D trap for quantum transport studies over long distances. We create custom spatially disordered channels as part of ???atomtronic??? circuits to study the effect of disorder in a manner directly analogous to electronic systems. Through measurements of the effective channel resistances, we observe the first signatures of Anderson localisation in a 2D ultracold atom system.

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  • Source Development and Dispersion Measurements in Optical Coherence Tomography

    Br??uer, B (2017)

    Doctoral thesis
    The University of Auckland Library

    OPTICAL coherence tomography (OCT) is a non-invasive imaging modality, which provides mm-deep cross sectional and volumetric images in real-time at micrometer resolution. Additional to its promising imaging capabilities it can provide label-free detection of flow in semi-transparent and translucent samples. OCT has gained great popularity in recent years due to enhanced laser and imaging technologies, offering unprecedented long range imaging at high speed. These technologies, however, are restricted to laboratories having lithography capabilities to manufacturer laser gain chips. Laboratories without the capability to manufacture laser gain chips still depend on the implementation of OCT systems having either long imaging range at slow speeds or high speed with decreased imaging range. Imaging range in swept source OCT (SS-OCT), one of the OCT configurations, is coupled with the coherence length of the laser. This thesis describes novel laser design configurations to close the gap between the imaging range and the A-scan speed of the laser while maintaining a cost effective approach for the design. The configuration used in the laser development is a modified laser cavity, based on the well known Littman-Metcalf design cavity. Lasers in the range of 1 m to 1.7 m were built and tested. These lasers were subsequently used for label-free detection and characterisation of tissue types in ocular media. Current tissue detection for optical imaging modalities are mostly based on staining of the sample. Label-free detection can be accomplished through material specific coefficients such as Young???s modulus (E) or the dispersion coefficient ( 2). In this dissertation label-free detection of biological and non-biological materials was accomplished by using the differential walk-off, induced by the refractive index difference of two wavelength regions travelling through a medium. The differential walk-off can be experimentally measured and used to calculate the dispersion coefficient 2, which is specific to different materials. The novelty in this technique is the use of dispersion for detection which is normally a non-favourable effect in optical imaging modalities, due to its degrading nature in image quality.

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  • Understanding and Controlling Unnamed Internet Traffic

    Janbeglou, Maziar (2017)

    Doctoral thesis
    The University of Auckland Library

    Despite the vast research on Internet security approaches that rely on the Domain Name System (DNS) to identify malicious activities, little is known about the communications that do not utilise the DNS. For example, we might not know the portion of our outgoing network traffic that does not employ the DNS and the applications that were involved in generating this traffic . Apart from the peer-to-peer (P2P) applications that employ different techniques of exchanging peer's endpoint information, some Internet applications contain hard-coded IP addresses of needed servers, and when executed, they make direct connections with those IP addresses. The Onion Router (TOR) and some types of malware and worms are common examples of these applications. Because they do not use the DNS, none of the DNS-based security solutions can identify such activity. Again, if known ports are used in this traffic , none of the existing security tools including firewall and web proxy can stop the communication. As a result, this type of traffic may be exploited by attackers in Internet connected networks. This thesis investigates `unnamed' traffic (traffic that does not employ the DNS) and proposes a solution of passively measuring DNS usage in a network, introduces a new method that tunnels all IPv4-based applications for P2P communications, identifies and extracts unnamed Internet traffic and understands the application of it, and subsequently proposes new techniques of detecting and blocking unnamed Internet traffic. The results of our experiments on the Internet traffic of the University of Auckland (UoA) have shown that not all outgoing Internet traffic employs the DNS. Also, we realise that a noticeable portion of the unnamed Internet traffic was classified as `unknown' for standard packet analyser tools. In addition, the results of DNS measurement using our unnamed Internet traffic blocker in a home network demonstrated that 100% of the outgoing communications used the DNS or were blocked. In the future, the blocker will be deployed and tested in larger networks and more features, including supporting IPv6, an option to drop unknown and unnamed traffic and whitelisting based on Internet applications rather than IP addresses will be added to it. Also, we hope to achieve speed improvement by deploying our blocker concept in kernel rather than user space.

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  • Predicting recovery and outcomes for the lower limb after stroke

    Smith, Marie-Claire (2017)

    Doctoral thesis
    The University of Auckland Library

    Regaining the ability to walk after stroke is the most common rehabilitation goal for patients. Recovery from motor impairment plays a role in achieving independent walking and the symmetry of the walking pattern. The objectives of this thesis were to identify predictors of recovery from lower limb motor impairment and walking outcome at the subacute stage of stroke, and to investigate an intervention for improving gait symmetry at the chronic stage of stroke. Two prediction studies were conducted using clinical measures, transcranial magnetic stimulation (TMS), and magnetic resonance imaging (MRI), within the first week of stroke, with follow-up assessments at 6 and 12 weeks post-stroke. The first study (n = 32) found that patients recovered about 70% of their initial lower limb motor impairment, with baseline motor impairment (lower limb Fugl-Meyer score) the only predictor of recovery. This is the first report of proportional recovery from lower limb motor impairment. The second study (n = 41) identified variables that predicted whether a patient would walk independently by six or 12 weeks, or remain dependent at 12 weeks post-stroke. The study produced the Time to Walking Independently after STroke (TWIST) algorithm that made accurate predictions for 95% of patients, and is the first to predict when a patient will walk independently post-stroke. TMS and MRI measures were not significant predictors in either study, which may be due to the presence of alternate descending pathways to the lower limb. The final study investigated unilateral step training and conventional treadmill training in 20 patients with chronic stroke. The effects of training were dependent on the direction of gait asymmetry, as both types of training improved step-length asymmetry only for participants who took a shorter step with their paretic leg. This highlights the need to identify subsets of patients who are most likely to respond to a given intervention. In summary, this thesis presents novel findings of proportional recovery from lower limb impairment, and the TWIST algorithm for predicting when a patient will achieve independent walking. Unilateral step training in the chronic stage had modest effects, but may have benefit at the subacute stage.

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  • Brain-computer interfaces for individuals with quadriplegic cerebral palsy: A user-centred, exploratory approach

    Taherian, Sarvnaz (2017)

    Doctoral thesis
    The University of Auckland Library

    Cerebral palsy (CP) is the most common form of childhood disability, affecting approximately 2-3 out of 1000 births per year. CP is an umbrella term describing a group of movement and posture disorders, caused by damage to the foetal or infant developing brain. Due to the severity of their physical impairment, it is difficult to gain access to technology that can enable them to communicate. Brain-computer interface (BCI) technology has been proposed as a new access method for individuals who have little to no motor control. This type of technology is unique as it does not require any physical capability on behalf of the user. Instead it functions through direct communication via neural activity produced by the brain with a computer, enabling even individuals with no muscular control with a means of communication and interaction. Although the technological components of BCIs have been researched heavily for over 50 years, they have not transitioned from research labs to the real world. The focus of the research was to apply an exploratory, user-centred approach to understand the contextual and usability factors that may influence the potential of BCIs for individuals with severe CP and those who care for them. This thesis that incorporates publications, includes the results of three main studies. The first study was a focus group that aimed to gain an understanding of the context of assistive technology (AT) use in New Zealand, through the experiences and perspectives of different stakeholders in the technology adoption process. Initially this study was inclusive of questions regarding user requirements for a BCI to be used as AT. However, participants noted that they did not hold adequate knowledge of the technology and wished for more experience before they felt comfortable addressing such questions. For this reason the next phase delved into the testing and evaluation of an existing commercial BCI by individuals with CP. A final study was completed to gain a more detailed understanding of the perceptions of special education staff and caregivers who took part in the trials, both observing and acting as proxies to our participants with CP. Participants were interviewed following the user testing process and to gain information on their experiences with the different components of the BCI system. Our results indicated that this commercial BCI was not suitable for independent use outside clinical/laboratory settings. Prior to use within an ecological environment, the hardware needs to be configurable, comfortable and accommodate physical support needs. The training approach needs to be less cognitively demanding, more motivating and support personalised mental tasks. For BCIs to transition into the real world, there should be adequate technological support, improved reliability, and a systemic assessment of how the technology will fit into the lives of end users. Participants emphasised the on-going need to involve users and individuals who support them, to create a system that truly meets the needs of the users.

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  • Elite Pakistani Men of Today: Negotiating Islam, Modernization and Culture

    Tahir, Tayyaba (2015)

    Doctoral thesis
    The University of Auckland Library

    This thesis provides an account of how young elite Pakistani men understand, negotiate and strategically deploy the concepts of Islam, culture, modernization and masculinity in their discourses and actions. The research is framed by Connell's and Messerschmidt's (2005) concept of the geography of masculinities which proposes that masculinities are shaped at the local, regional and global levels. I show how these young men???s masculinities are shaped by global discourses about Islam and modernization, the idea of a regional identity as Pakistani citizens, and multiple locals. Multiple locals include their home, village or city, their social location as elites, and their positions as students at the Lahore University of Management Sciences (LUMS). I draw on the notion of multiple modernities (Eisenstadt, 2000), to illuminate my informants??? aspiration for a Pakistani modernity that blends in Pakistani cultural and Islamic values with some values of modernization. I argue that the conflict between Islam and modernization in the discourses of the informants is exaggerated, and that this conflict is often moderated by the notion of culture. Many informants affirm that Islam plays a pivotal role in their lives and modern values are equally essential for them to be successful men. The centrality of ???culture???, familial, social and local, in shaping their major life-choices surpasses their aspirations to be Islamic and at the same time modern. On one hand, there is a tension that some aspects of Pakistani culture conflict with Islam and there is a constant effort to bring Pakistani culture close to Islamic values. On the other hand, there is a fear of Pakistani culture being polluted by western culture and an effort to resist some aspects of western culture. An Islamic nikkah, a Pakistani wedding and a modern honeymoon is the idea of an ideal marriage for an average upper class man in Pakistan. The masculinities of young urban Pakistani men are partially shaped by cultural-religious and culturally-modern forces and the adjustments that these men make in their life choices in relation to these forces make them modern Pakistani men.

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  • Young People and Staff Perspectives on Offender Rehabilitation

    Mati, Elizabeth (2016)

    Doctoral thesis
    The University of Auckland Library

    It is important that evidence-based interventions that address the dynamic risk factors of offending are implemented to reduce youth offending. Equally important, is the ability of service providers to engage young people to attend and participate in interventions that elicit positive change. The current study used qualitative methods to explore treatment and facilitator factors that increase engagement, improve the therapeutic relationship and facilitate pro-social change. The Genesis Youth Programme (GYP) in South Auckland provides multiple coordinated services for young people who offend. Fifteen M??ori and Pacific young people who have been involved in the GYP were interviewed. A focus group with five of the GYP facilitators was also completed. Realist, M??ori and Pacific epistemologies informed the separate thematic analyses performed on the two sets of data. The two sets of data were categorised under the three main topics of facilitator characteristics, intervention characteristics and youth characteristics. Overall the young people evaluated the GYP favourably and described the facilitators as being non-directive, available and honest. Most of the young people reported ethnic matching was not essential and instead reported the qualities of being non-judgmental and respectful as more important. The young people made reference to personal reasons for change and reported a strong sense of ethnic pride. GYP was described favourably as a place that promotes change, where they received services that were helpful. The facilitators reported being available and honest with the young people was necessary for engagement. In addition, expressing unconditional positive regard and humour helped to build a positive relationship. The facilitators reported the intervention characteristics contributing to intervention success were the GYP???s values, their tendency to respond to need, and their shared approach to caring for the young people. In contrast, resource and system restraints were seen as negatively impacting on the services offered. Social issues and teenage parenting were also extracted from the focus group data. These findings are discussed in relation to existing literature and implications for service improvements are presented.

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  • Insulin Resistance and Inflammation in Neurodegeneration: Lessons from in vitro Models

    Jansson, Deidre (2015)

    Doctoral thesis
    The University of Auckland Library

    Type 2 diabetes (T2D) is a growing epidemic of the developed world and significantly increases the risk for neurodegenerative diseases such as Alzheimer???s disease (AD). Current evidence suggests that these two diseases are closely linked. Both share common etiologies such as insulin resistance (IR) and chronic inflammation. While it was once believed that the brain was not susceptible to the peripheral environment, it has now been demonstrated that systemic conditions impact the brain, especially so in metabolic conditions such as T2D, where blood brain barrier (BBB) permeability is prevalent. The exact mechanisms of how reduced insulin sensitivity and chronic inflammation are translated to the brain and the subsequent consequences in the central nervous system are not entirely understood. This thesis utilizes in vitro models of human brain cells to examine the effects of IR and chronic inflammation in neurons and pericytes that line the BBB. A chronic insulin model of insulin resistance in differentiated human neurons was developed to examine changes in gene expression associated with an insulin resistant state. Microarray analysis revealed altered expression of transcripts that regulate cholesterol and lipid metabolism. This is important because cholesterol homeostasis is required for efficient neuronal signalling and protein trafficking, and disruption of this balance results in AD-like pathologies. Pericytes are crucial components of the BBB and together with endothelial cells, astrocytes, and neurons, comprise the neurovascular unit. Brain pericytes are required for neurovascular regulation, and BBB integrity. Pericyte dysfunction is also an early pathology associated with diabetic retinopathy indicating these cells are exposed to systemic conditions. For the first time, this study demonstrated that cultured human brain pericytes exposed to cytokines associated with systemic inflammation responded by secreting chemokines IP-10 and MCP-1. Microarray analysis of pericytes treated with proinflammatory cytokines IFN?? and IL-1?? revealed an extensive immune signature, identifying these cells as dynamic participants in the immune response. Pericytes were also exposed to chronic cytokine treatment in order to model systemic inflammation, typified by diabetic conditions. Chronic inflammation was shown to affect protein and gene expression of ?? smooth muscle actin (SMA) and platelet-derived growth factor receptor beta (PDGFR??), two critical proteins involved in pericyte biology. Recent studies have demonstrated that PDGFR?? is required for pericyte function and survival in animal models. Indeed knockdown of PDGFR?? in human brain pericytes resulted in reduced proliferation in response to PDGF treatment, however, had no effect on overall cell numbers. Interestingly, chronic inflammatory conditions mimicked the PDGFR?? knockdown phenotype with blocked PDGF induced proliferation in pericytes. Taken together these data indicate that systemic conditions such as chronic high insulin and inflammation can have deleterious effects on human brain cells, and offers mechanistic explanations for the relationship between T2D and AD at a cellular level.

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  • The Darkening Arctic from Space: Quantification and Application

    Zhan, Yizhe (2017)

    Doctoral thesis
    The University of Auckland Library

    The darkening Arctic that results from global warming was hypothesized 50 years ago and confirmed only recently by satellite observations. Compared to the notable surface darkening as reported in extensive publications, the darkening at the top-of-atmosphere (TOA) has been studied insufficiently and shows a significant divergence in magnitude among the limited references. Hence, it raises an urgent need to quantify the Arctic TOA darkening from an observational perspective. To assess the operational TOA albedo observations, both instrument calibration and retrieval algorithm have been checked between the Clouds and the Earth???s Radiant Energy System (CERES) and Multiangle Imaging SpectroRadiometer (MISR). While the intercalibration experiment confirmed the stability of CERES long-term measurements and accounted for most of the discrepancies in their TOA albedo trends, the remaining differential trends were likely due to the biased MISR albedo retrievals that mainly resulted from the inaccurate scene identification. These results strongly enhanced the confidence in the temporal trends of TOA albedo measured by the CERES. The magnitude, seasonality, and contributing sources of the Arctic TOA albedo changes were then examined by CERES and compared to four state-of-the-art reanalysis data sets. A significant declining TOA albedo of ???0.012??0.003 per decade was observed within the Arctic Ocean between 1982 and 2015. The darkening occurred in every sunlit month and experienced an accelerated (damped) darkening in the early (late) melt season. Furthermore, changes in surface albedo not only accounted for most of the TOA darkening trends but also largely explained the variations in the TOA albedo anomalies. Nevertheless, no reanalysis product was able to fully reproduce this change, particularly in the summer months. Being closely related to the underlying sea ice condition, June TOA reflected solar radiation showed a robust 3-month lag correlation with September sea ice extent (SIE). The small hindcast prediction errors, high forecast skill, and the capability of predicting September SIEs with large negative anomalies are similar to or better than other complex models. The results emphasized the particular importance of the early summer sea ice state for the subsequent ice evolution and served as an application of the satellite TOA albedo product.

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  • Power Ultrasound and High Pressure Processing Inactivation of Specific Microbial Spores in Foods

    Evelyn, Evelyn (2016)

    Doctoral thesis
    The University of Auckland Library

    Bacterial and fungal spores are a great concern in food industries due to their extreme resistance to physical and chemical treatments. Thermal processing at high temperatures often diminishes food quality. Therefore in this study, high pressure processing (HPP) and power ultrasound alone and in combination with heat (HPP-thermal) and thermosonication (TS) were investigated for their abilities to inactivate the spores of Clostridium perfringens and psychrotrophic Bacillus cereus in low-acid (pH>4.6) foods, and Alicyclobacillus acidoterrestris, Neosartorya fischeri, and Byssochlamys nivea spores in high-acid (pH<4.6) foods. The spore inactivation was compared with thermal processing alone and the inactivation kinetics was modeled. The 600 MPa HPP-thermal and TS treatments were better than thermal processing alone for the microbial spore inactivation, requiring between 8???30??C lower temperatures to obtain the same lethality. The 600 MPa HPP-75??C was the best technique to inactivate C. perfringens in beef slurry, and N. fischeri, and B. nivea moulds in juice/puree. With respect to C. perfringens, spore reductions of ???2 log after 20 min were obtained for HPP-thermal vs. almost no inactivation for TS and thermal processes. Regarding the moulds, the 600 MPa HPP-75??C inactivated ???4 log after 20 min, while the TS and thermal treatments increased the spore numbers by up to 2.5 log. Regarding B. cereus spores, TS was the most effective method to inactivate them in skim milk and beef slurry. Over 15 min, TS caused ???5 log in milk vs 3 log after HPP-thermal and 2 log with thermal process. In beef slurry, TS was actually able to increase the thermal spore inactivation in beef slurry by more than 6 fold. TS and thermal processing alone at 78??C had no effect on A. acidoterrestris spores. However, TS treatment (78??C) of HPP pretreated spores suspended in orange juice increased the spore inactivation by ???1.6 fold. Lower D-values were obtained at higher acoustic power densities. In addition, heat shock (HS) and ultrasonication pretreatment of the spores doubled the spore thermal inactivation of C. perfringens and A. acidoterrestris: pretreated C. perfringens spores D95??C = 9.8 min vs 22 min in beef slurry; pretreated A. acidoterrestris spores D95??C = 0.8 min vs 1.5 min in orange juice. With respect to overall spore resistance to different technologies at 70-75??C, psychrotrophic B. cereus spores were the least resistant. The spores of B. nivea and N. fischeri showed the highest resistance to thermal treatment over 30 min. A. acidoterrestris and C. perfringens were more difficult to inactivate with TS processing and C. perfringens was more difficult to inactivate with HPP-thermal treatment. The mould ascospore resistance to HPP-thermal and TS processes increased with increasing spore age. Regarding 4 week old N. fischeri spores at 75??C TS or HPP-thermal, 27 min were required for 1 log reduction, whereas 74 min was required to obtain the same spore inactivation for 12 week old spores. With respect to 4 week old B. nivea spores, the results were closer. While 13 min were required for 1 log reduction, 29 min were required to obtain the same spore inactivation for 12 week old spores. The HPP-thermal inactivation for all the microbial spores was well described with the Weibull model, whereas the inactivation kinetics for TS treatment was species/strain/food dependent. The TS inactivation of psychrotrophic B. cereus spores in skim milk and A. acidoterrestris spores in orange juice followed simple first order kinetics, whereas log logistic and Weibull models described the TS inactivation of B. cereus and C. perfringens spores in beef slurry, respectively. Lorentzian distribution modeled the 4-10 week old mould spore inactivation with TS treatment. With the exception of thermal inactivation of mould spores at T ??? 85??C, all the spore thermal inactivations followed the simple first order kinetic model.

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  • An Evaluation of Puawaitahi: New Zealand's First Multi-Agency for Child Protection

    Stevenson, Rachel (2017)

    Doctoral thesis
    The University of Auckland Library

    Puawaitahi is New Zealand???s first multi-agency service for child protection. It incorporates health, child protection, Police, evidential interviewing, and therapy services at one centralised location. This research aimed to examine the processes and procedures within the multi-agency. Focus groups and interviews were conducted with staff, referrers and children and families who had been seen within the service. Transcripts were analysed to identify common themes in relation to the multi-agency processes and procedures, the organisation???s culture, accessibility, coordination, timeliness, quality of care, and areas for programme improvement. The programme evaluation found that Puawaitahi meets the majority of its own vision and mission statement goals and performs well in relation to the standards described for Child Advocacy Centres as they are known elsewhere. In particular, the multi-agency processes and procedures provided effective case coordination, and the physical environment, child focused service delivery, staff cultural competence, and interactions with stakeholders were rated highly by most participants across staff, referrer and consumer groups. Desired improvements included better access to therapy, changes to client referral and case coordination processes to further reduce delay, better client follow up procedures, and provision of the multi-agency model across every region in Auckland. This evaluation shows that a model inspired by USA Child Advocacy Centres has been effectively implemented and Puawaitahi stands as a model for implementation elsewhere in New Zealand. Issues concerning the evaluation of such programmes are discussed.

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  • Human Amniotic Epithelial Cell Therapy for Neuroprotection and Neuro-repair after Perinatal Asphyxial Brain Injury

    Van den Heuij, LG (2017)

    Doctoral thesis
    The University of Auckland Library

    The primary purpose of this thesis was to investigate the effects of human amniotic epithelial cells (hAECs) on preterm and term brain injury after hypoxic-ischaemic (HI) insults. I also examined the long-term effects of asphyxia on the neural development, and the pre-HI conditioning of inflammation on the preterm fetal responses to asphyxia. A secondary aim was to assess the effect of hAECs on the recovery of fetal EEG, cardiovascular and cerebrovascular activity, biochemistry and cytokines after HI insults. In chapter 3, I tested the hypothesis that acute-on-chronic exposure to LPS would exacerbate white matter injury after subsequent asphyxia in preterm fetal sheep. Contrary to this hypothesis, the combination of acute-on-chronic LPS with subsequent asphyxia reduced neuroinflammation and white matter injury. In chapters 4 and 5, I examined the effect of hAECs given i.c.v. at 2 and 24 hours post- asphyxia in preterm fetal sheep, with outcomes studied at 7 days. HAEC treatment in both groups significantly reduced neuronal injury in selected subcortical regions, and improved CNPase positive cells in selected regions. These changes were associated with a significant reduction in microglia and astrocytes in both groups, and reduced plasma pro-inflammatory and increased anti-inflammatory cytokines and modulated seizure activity in the 2 hour, but not the 24 hour study. In chapter 6, I investigated the 21 day recovery of preterm fetal sheep after asphyxia, and observed that inflammation does not resolve. HAEC treatment via intranasal administration at 1, 3 and 10 days after asphyxia significantly reduced neuronal injury, white matter hypomyelination, neural inflammation, and improved EEG maturation. In chapter 7, I examined the effects of hAECs given intravenously on injury after cerebral ischaemia with a 7 day follow-up. HAECs did not improve neuronal or glia cell loss, or reduce inflammation. Treatment was associated with an earlier onset of seizures. My data demonstrate, for the first time, that hAECs are neuroprotective after an HI insult in preterm, but not term fetal sheep. Treatment efficacy is in part due to immunomodulation. We did not observe an effect on cardiovascular or cerebrovascular variables suggesting the treatment is safe.

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