13,001 results for University of Canterbury Library

  • Seismic resistant design of base isolated multistorey structures

    Andriono, Takim (1989)

    Doctoral thesis
    University of Canterbury Library

    The Base Isolation technique and its benefits in reducing the transmitted earthquake energy into a structure has gained increasing recognition during the last two decades. This recognition is indicated by the application of Base Isolation systems to a large number of bridges, several multistorey buildings and some power plants in countries which have high seismic risk. Unfortunately, the currently available design procedures, especially for multistorey structures, seem inadequate and too restrictive and as a result present practice still relies upon a series of deterministic time history analyses which are not only impractical for design purposes but appear unable to give the designer a clear insight into the seismic behaviour of the multistory structure. This research is carried out to investigate in more detail the effects of various structural parameters and ground motion characteristics on the seismic response of Base Isolated multistorey structures. It also reviews the shortcomings of the current design methods. The results are then used to develop two simplified analysis methods for practical design. The first method which is called the Code-Type approach can be used to accurately estimate the inertia forces, not only at the level of the isolation devices but throughout the height of the multistorey structure. It is recommended for use as a preliminary design tool or even a final design tool for simple Base Isolated multistorey structures. The second procedure which is based on the Component Mode Synthesis method is suggested for final design purposes of more complex Base Isolated multistorey structures. This method enables the designer to evaluate the effects of the isolation devices on the contribution of each mode of vibration to the total response of the structure.

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  • Taxonomic delimitation and the evolutionary history of the Australasian Lautusoid group of Senecio (Asteraceae)

    Liew, Chia-Sin (Jasmine) (2016)

    Doctoral thesis
    University of Canterbury Library

    Taxonomic delimitation can be a challenging task for systematists, because of the dynamic and complex evolutionary processes that shape patterns of biodiversity. Yet, it is an essential aspect of biology, because it defines units of evolutionary significance, which form the basis for studying all aspects of biodiversity. In this thesis, I studied the taxonomic delimitation and evolutionary history of the Australasian Lautusoid group of Senecio at the infrageneric, species, and infraspecific level. Members of the Lautusoid group are morphologically very diverse and occupy a wide array of habitats. Moreover, the Lautusoid group has a large diversity of chromosome profiles compared to other Australasian Senecio, which indicates the possible occurrence of hybridization in its evolutionary history. These patterns of diversity make it an attractive system for various evolutionary and ecological studies. Despite these interesting characteristics and the inclusion of members of the Lautusoid group in a number of taxonomic treatments, it is not known how many and which species form the Lautusoid group. To determine the delimitation of the Lautusoid group and to investigate the origin of Lautusoid species with higher chromosome numbers, a molecular phylogenetic study was carried out. The results of this study indicate that the group is a morphologically and phylogenetically distinct Senecio lineage with an Australasian distribution. These results also highlight the important role of hybrid speciation in the evolutionary history of the Lautusoid group by identifying allopolyploid hybrids between members of the Lautusoid group and members of other Australasian lineages. An allopolyploid species complex that was found to be affiliated with the Lautusoid group, S. glaucophyllus, was the focus of subsequent studies. Senecio glaucophyllus and a morphologically similar informally named taxon, S. aff. glaucophyllus, were examined to determine if they are distinct species. The results confirm that the two taxa are indeed morphologically and genetically distinct. However, against expectation, this study revealed that S. aff. glaucophyllus is the true S. glaucophyllus and that the plants that were called S. glaucophyllus belong to a species that is presently unnamed. This taxon, tentatively called S. “pseudoglaucophyllus”, aligns with S. glaucophyllus sensu Ornduff excluding S. glaucophyllus Cheeseman. In order to revisit the current classification of recognizing four infraspecific groups for S. “pseudoglaucophyllus” and to propose taxonomic recommendations, studies that look into its morphological and genetic diversity were performed. The results of these studies show that patterns of morphological variation in S. “pseudoglaucophyllus” are not congruent with patterns of genetic variation and that neither supports the current classification in which four infraspecific groups are recognized. Because infraspecific taxon boundaries cannot be unambiguously determined for S. “pseudoglaucophyllus”, this species is therefore best regarded as a single variable New Zealand species for which infraspecific groups should not be formally recognized.

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  • Acoustic analysis of slow click function and foraging in sperm whales (Physeter macrocephalus) off Kaikoura, New Zealand

    Fernandes, Manuel Goulartt de Medeiros de Carvalho (2016)

    Doctoral thesis
    University of Canterbury Library

    Sexually immature male sperm whales (Physeter macrocephalus) disperse from their natal areas and move to higher latitude male-only foraging grounds, such as those off New Zealand and Norway. In these areas they are found in aggregations, in which a relatively high concentration of animals congregate in a specific area. Males within aggregations continuously forage, yet seemingly dive in a solitary manner. The Kaikoura submarine canyon off New Zealand is an area where male sperm whales aggregate. This canyon is among the most productive deep sea regions in the world, and has been used for foraging both by individual male sperm whales over years, as well by transient animals which have only been seen once. Slow clicks are vocalisations only used by males. Typically displayed in bouts with inter-click intervals of 3-9 s, they consist of low frequency (2-4 kHz) sharp clicks with a strong reverberation and apparent source levels around 201 dB peak re 1 μPa at 1 m. Slow clicks have much lower directionality than regular echolocating clicks, resulting in their characteristic strong and lasting seafloor echo. At breeding grounds, slow clicks seem to be displayed in long sequences while males are close to, or at the surface, and these have been suggested to function as vocal display used in competition and/or to attract females. In contrast, at male-only foraging grounds, slow clicks are heard in shorter sequences at the end of foraging dives (and also, at times, during surfacing), with these being heard in almost half of all foraging dives recorded in this study. The diving-phase pattern associated with slow clicks appears consistent across male aggregations recorded here, off Kaikoura, and those found off Norway1. While the function of slow clicks is still unclear, the different social and slow-clicking patterns observed suggests a context-dependent function in communication. I used a towed hydrophone array and photo-identification data from individually-tracked whales during complete foraging dives to further understand the function of slow clicks in the Kaikoura foraging ground. I investigated the presence and number of slow clicks as a function of other acoustically-detected whales in the area, which indicated an increased rate of slow clicking with increasing number of ‘neighbours’. I examined slow click structure, including centre frequency, waveform, and, as body size-related information is encoded in regular echolocating clicks, the occurrence of multiple pulses within clicks, to examine the relationship between this vocalisation and body length. The centre frequency of slow clicks differed between individuals and their waveform revealed a multi-pulsed structure in seventy percent of clicks analysed. However, neither the inter-pulse interval (time between pulses within a click) of slow clicks, nor their centre frequency, correlated with body size. Additionally, the analysis of the pulse structure and amplitude of slow clicks within bouts suggests that slow clicks display a broad but somewhat defined directionality, which may allow slow clicking whales to target goals by adjusting their body posture. Additionally, I explored the use of slow clicks and codas, which are stereotyped patterns of clicks used for communication, produced by a pair of males synchronising their surfacing time and dives. Over a complete dive cycle and surfacing time I examined the spectral characteristics and waveform of codas (click sequences) and slow clicks, as well as coda duration. Codas made using clicks with spectral and waveform characteristics of slow clicks were termed “slow click codas”. These were longer, and showed lower centre frequency and higher relative amplitude than traditional codas and may suggest some form of communication between whales in synchrony. Finally, I looked at the feeding vocalisation (creak) rate, duration, and the relationship between creak presence, bathymetry and the commercial fisheries within the underwater canyon off Kaikoura as a proxy for areas with an abundance for potential prey. Results suggest that males in this area may be targeting fewer but larger and/or more nutritious prey (i.e. fewer but longer creaks) compared to other studied areas. In conclusion, the diving phase-related use of slow clicks, their acoustic properties, including the centre frequency and waveform related information, coupled with the field observations analysed and the history of male bachelor group composition, suggests that slow clicks may function as a contact call, which could be used for individual and/or group recognition.

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  • Girl in Progress: Navigating the Mortal Coils of Growing Up in the Fiction of Jacqueline Wilson

    Clark, Cherilyn Nicole (2016)

    Masters thesis
    University of Canterbury Library

    The following presents a discussion of the work of children’s and young adult novelist, Jacqueline Wilson. My focus is on Wilson’s treatment of issues that are quite pertinent to growing up and growing up as a girl in particular. Each chapter looks at a specific novel, considering Wilson’s representations of such issues as self-harm, eating disorders, and parental mental illness. In doing so, I will approach my subjects from various perspectives, drawing on theory from strands of psychoanalysis, post-structuralism, and feminism among others. In doing so I hope to prove the worth of Wilson’s work for future critical study (at this stage there has been little written specifically on this author). An interest of mine is the presence of ideology in children’s and young adult literature (a certain pedagogy that primarily serves the interests of adults). In discussing the ways in which Wilson presents the above issues, I consider ways in which her work may be seen to subvert such ideologies while still maintaining a sense of responsibility regarding the ability of narratives to influence young audiences. As such, part of my discussion will consist of an analysis of what has been termed by such writers as Melissa Wilson and Kathy Short, and David Elkind as a “postmodern childhood.” One in which children must navigate a problematic and less than ideal adult world and in which a developmental endpoint is never certain.

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  • Bounds on causal parameters of prospective ground motions and their effect on characteristics of selected ground motions

    Tarbali, K.; Bradley, B.A. (2015)

    Reports
    University of Canterbury Library

    In this study, the effect of considering bounds on causal parameters of prospective ground motions (e.g., magnitude, source-to-site distance, and site condition) for the purpose of ground-motion selection is investigated. Although using bounds on causal parameters is common practice in conventional approaches for ground motion selection, there is presently no consistent approach for setting these bounds as a function of the seismic hazard at the site. A rigorous basis is developed and sensitivity analyses performed for the consideration of bounds on magnitude, source-to-site distance, and site condition for use in ground motion selection. In order to empirically illustrate the effects of various causal parameter bounds on the characteristics of selected ground motions, 78 and 36 cases of scenario seismic hazard analysis (scenario SHA) and probabilistic seismic hazard analysis (PSHA) are considered, which cover a wide range of causal parameters and site conditions. Ground motions are selected based on the generalized conditional intensity measure (GCIM) approach, which considers multiple ground motion intensity measures (IMs) and their variability in order to appropriately represent characteristics of the seismic hazard at the site. It is demonstrated that the application of relatively ‘wide’ bounds on causal parameters effectively removes ground motions with drastically different characteristics with respect to the target seismic hazard (improving computational efficiency in the selection process by reducing the subset of prospective records), and results in an improved representation of the target causal parameters. In contrast, the use of excessively ‘narrow’ bounds can lead to ground motion ensembles with a poor representation of the target IM distributions, especially for ground motions selected to represent PSHA results. As a result, the causal parameter bound criteria advocated in this study provide a good ‘default’ that is expected to be sufficient in the majority of problems encountered in seismic hazard and demand analyses.

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  • A new genetic algorithm based clustering for binary and imbalanced class data sets

    Saharan, Sabariah (2016)

    Doctoral thesis
    University of Canterbury Library

    This research was initially driven by the lack of clustering algorithms that specifically focus on binary data. To overcome this gap in knowledge, a promising technique for analysing this type of data became the main subject in this research, namely Genetic Algorithm (GA). This type of algorithm has an intrinsic search parallelism that avoids getting stuck at the local optima and poor initialization. For the purpose of this research, GA was combined with the Incremental K-means (IKM) algorithm to cluster the binary data streams. However, prior to this proposed method, a well-known GA based clustering method, GCUK was applied to gauge the performance of this algorithm to cluster the binary data, with new application for binary data set. Subsequently, this led to a proposed new method known as Genetic Algorithm-Incremental K-means (GAIKM) with the objective function based on a few suff- cient statistics that may be easily and quickly calculated on binary numbers. Different from the other clustering algorithms for binary data, this proposed method has an advantage in terms of fast convergence by implementing the IKM. Additionally, the utilization of GA provides a continuous process of searching for the best solutions, that can escape from being trapped at the local optima like the other clustering methods. The results show that GAIKM is an effcient and effective new clustering algorithm compared to the clustering algorithms and to the IKM itself. The other main contribution in this research is the ability of the proposed GAIKM to cluster imbalanced data sets, where standard clustering algorithms cannot simply be applied to this data as they could cause misclassification results. In conclusion, the GAIKM outperformed other clustering algorithms, and paves the way for future research in missing data and outliers and also by implementing the GA multi-objective optimization.

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  • Building-specific seismic resilience assessment frameworks considering content sliding and injury

    Yeow, Trevor Zhiqing (2017)

    Doctoral thesis
    University of Canterbury Library

    In this thesis, frameworks are developed to: (i) quantify the severity of content movement; (ii) predict injuries caused by people losing balance and falling over, or from movement of building contents; and (iii) assess structural damage and injury-related losses caused by earthquakes. These frameworks are then applied to various structural forms to assess which has lower overall life-cycle costs and higher seismic resilience. The first stage of this research investigated the influence of structural form on building structural and non-structural damage direct-repair costs using existing seismic loss estimation frameworks. In general, it was found that the stiffer building and stronger building considered incurred lower expected annual losses compared to more flexible buildings and weaker buildings. However, cost-benefit assessment showed that stiffer buildings and stronger buildings had higher life-cycle costs when initial construction costs were included. The second stage focused on quantifying the severity of content movement; in particular content sliding. Existing numerical content sliding models were validated using shaking table tests of realistic furniture on common flooring materials subjected to sinusoidal floor motion. A new equation for predicting the peak sliding displacement of contents was then developed. This equation was found to be more sufficient and efficient compared to other existing prediction equations. Furthermore, it was found that sliding of contents within stiffer buildings were generally less severe compared to more flexible buildings. In contrast, contents in stronger buildings exhibited greater sliding response compared to weaker buildings. A framework for predicting injuries caused by people falling, content movement, and building collapse was developed in the third stage of this research. Outputs from this framework were found to be consistent with anecdotal injury data. It was found that fall-related injuries were more likely to occur in stiffer buildings and stronger buildings. In addition, lesser content movement-related injuries occurred in stiffer buildings compared to more flexible buildings. However, more content movement-related injuries occurred in stronger buildings compared to weaker buildings. Lesser collapse-related injuries occurred in stiffer buildings and stronger buildings. The final stage of this research investigated the influence of structural forms on life-cycle costs including initial construction costs, building damage direct-repair costs, and injury costs. Cost-benefit analyses showed that stiffer buildings generally have lower overall life cycle costs, and the highest seismic resilience, of all buildings considered.

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  • Response of instrumented buildings under the 2016 Kaikoura earthquake

    Chandramohan, Reagan; Wotherspoon, L. M.; Bradley, B. A.; Nayyerloo, M; Uma, S. R.; Stephens, M. T. (2017)


    University of Canterbury Library

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  • Where is Craft located? : conversations about work, home and history : an ethnography with artisans in Telangana, India.

    Bose, Chandan (2016)

    Doctoral thesis
    University of Canterbury Library

    This thesis is based on ethnographic fieldwork with a family of artisans in the Telangana state of southern India, who are skilled at crafting the region’s style of murals, masks and figurines and etiological scrolls. Specifically, centred on the question, ‘where can one locate craft?’ the following ethnography situates as its point of departure existing scholarship which construct the different epistemological sites within which Craft as a category emerges. By dwelling upon narratives of practitioners about the organization of everyday life around the practice, and the history of the familial studio, this dissertation attempts to read the critical language which practitioners assemble together in order to negotiate with these epistemic frames. Effectively my doctoral dissertation looks at the way in which the practice of craft is not located within a defined universe of internally organized meanings and relationships waiting to be explored by the anthropologist. This project is in fact a step towards exploring the language within which practice, and the histories and artefacts which it fashions, emerge. The language could be derived from collective memory which have been inscribed by the geographical, temporal, metaphysical and philosophical terrains which rules of a practice trace. The language is generated within the way in which the artisan experiences the relationship between materials and tools, and the way in which this experience is historicized. The language could be appropriated and reproduced through imaginations of self and personhood, articulated through the way in which relations between kin are constructed and deconstructed in craft practices. The language emerges as practitioners, in an attempt to express desire for the nation-state, dismantle, interrogate and re-narrate the fixity and actuality of heritage and regional belongingness. The language evolves with the way in which the practitioners have come to co-author the way in which conditions of material realities of production, consumption and circulation that have altered within a global market. This dissertation warrants the abandonment of a privileged site or absolute centre where the practice of craft can be located. Rather it proposes a certain reading of craft, namely as a network everyday practices, relationships and language within which artisans situate themselves to express their capacity to imagine and act on those possibilities.

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  • Spatial Point Processes and Moment Dynamics in the Life Sciences: A Parsimonious Derivation and Some Extensions

    Plank, M.J.; Law, R. (2015)

    Journal Articles
    University of Canterbury Library

    Mathematical models of dynamical systems in 6 the life sciences typically assume that biological systems are spatially well mixed (the mean-field assumption). Even spatially explicit differential equation models typically make a local mean-field assumption. In effect, the assumption is that diffusive movement is strong enough to destroy spatial structure, or that interactions between individuals are sufficiently long-ranged that the effects of spatial structure are weak. However, many important biophysical processes, such as chemical reactions of biomolecules within cells, disease transmission among humans, and dispersal of plants, have characteristic spatial scales that can generate strong spatial structure at the scale of individuals, with important effects on the behaviour of biological systems. This calls for mathematical methods that in corporate spatial structure. Here we focus on one method, spatial-moment dynamics, which is based on the idea that important information about a spatial point process is held in its low-order spatial moments. The method goes beyond dynamics of the first moment, i.e. the mean density or concentration of agents in space, in which no information about spatial structure is retained. By including the dynamics of at least the second moment, the method retains some information about spatial structure. Whereas mean-field models effectively use a closure assumption for the second moment, spatial-moment models use a closure assumption for the third (or a higher-order) moment. The aim of the paper is to provide a parsimonious and intuitive derivation of spatial-moment dynamic equations that is accessible to non-specialists. The derivation builds naturally from the first moment to the second and we show how it can be extended to higher-order moments. Rather than tying the model to a specific biological example, we formulate a general model of movement, birth and death of multiple types of interacting agents. This model can be applied to problems from a range of disciplines, some of which we discuss. The derivation is performed in a spatially non-homogeneous setting, to facilitate future investigations of biological scenarios, such as invasions, in which the spatial patterns are non-stationary over space.

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  • On Brauer groups of double covers of ruled surfaces

    Creutz, B.; Viray, B. (2015)

    Journal Articles
    University of Canterbury Library

    Let X be a smooth double cover of a geometrically ruled surface defined over a separably closed field of characteristic different from 2. The main result of this paper is a finite presentation of the 2-torsion in the Brauer group of X with generators given by central simple algebras over the function field of X and relations coming from the N\'eron-Severi group of X. In particular, the result gives a central simple algebra representative for the unique nontrivial Brauer class on any Enriques surface. An example demonstrating the applications to the study of rational points is given.

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  • Two torsion in the Brauer group of a hyperelliptic curve

    Creutz, B.; Viray, B. (2015)

    Journal Articles
    University of Canterbury Library

    We construct unramified central simple algebras representing 2-torsion classes in the Brauer group of a hyperelliptic curve, and show that every 2-torsion class can be constructed this way when the curve has a rational Weierstrass point or when the base field is C 1. In general, we show that a large (but in general proper) subgroup of the 2-torsion classes are given by the construction. Examples demonstrating applications to the arithmetic of hyperelliptic curves defined over number fields are given.

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  • Is sustainability reporting becoming institutionalised? The role of an issues-based field

    Higgins, C.; Stubbs, W.; Milne, M.J. (2016)

    Journal Articles
    University of Canterbury Library

    We study companies that do not produce a sustainability report in contexts where institutionalization is assumed. Based on a careful analysis of interaction patterns between non-reporting companies, sustainability interest groups, and peer organisations we find patterns of discursive and material isomorphism that suggest sustainability reporting is confined to an issues-based field, rather than spreading as an institutionalised practice across the business community. We argue that the issues-based field exerts only weak pressure for sustainability reporting, and that encouraging more firms to report rests on understanding what influences companies to interact more widely to become part of this field.

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  • The Chinese writer as empty signifier: a corpus-based analysis of the English-language reporting of the 2012 Nobel Prize in Literature

    Xin, J.; Matheson, D. (2015)

    Journal Articles
    University of Canterbury Library

    This study examines the English-language reporting of the award in 2012 of the Nobel Prize in Literature to the Chinese author, Mo Yan. Through the corpus-based analysis of news reporting in four countries, the study found that Mo was discursively produced as an “empty signifier” through which significant cultural-political work was done in an attempt to make sense of and manage a resurgent China. Specifically, the global cultural event of the Nobel Prize in Literature was used in the US, Australian, and French news media largely to reproduce the dominant human rights discourse in which China’s dissidents were highly prominent and highly valued. In the news media of the more culturally proximate India, the literary achievement was given greater prominence. The study’s keyword and concordance analyses found a high degree of commonality in the linguistic strategies through which China was represented. The findings revealed that the English-language reporting of the Nobel Prize was characterized by narrow cosmopolitanism, in which “they” were invited to become part of “our” free world.

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  • Ecology and biology of the banded wrasse, Notolabrus fucicola (Pisces: Labridae) around Kaikoura, New Zealand.

    Denny, Christopher Michael (1998)

    Masters thesis
    University of Canterbury Library

    Notolabrus fucico/a, a large common labrid inhabiting shallow waters around New Zealand and Southern Australia, were collected monthly (Dec 1996 to Feb 1998) around Kaikoura. They were found to be pelagic synchronous spawners and followed the typical labrid spring-summer seasonal pattern of reproduction (July to December). Compared to other New Zealand labrids that are protogynous hermaphrodites, N. fucico/a was found to be a secondary gonochorist, where individuals change sex before maturation. Although two colour phases are present, they are a monochromatic species with males and females found in all size classes and colour phases (a ratio of females to males 1.6: 1 ). Sexual maturity is attained between 2 - 3 years old and they can live upwards of 25 years. There was no significant difference in numbers across time or depth for N. fucicola but a significant difference was recorded for size with depth. N. fucicola is a generalist predator with seasonal variations in prey items. There were size specific changes in the diet from soft to hard-bodied prey. Seasonal variations were also recorded in gut fullness and condition. They are a territorial species that are likely to defend areas for food or shelter, but not spawning.

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  • The effects of a brief generalisation intervention on social interactions for three adolescents with Down Syndrome.

    Fifield, Gabrielle (2016)

    Masters thesis
    University of Canterbury Library

    The main aim of this study was to measure the effectiveness of a brief generalisation intervention on teaching adolescents with disabilities to generalise specific social skills to two familiar environments. Participant and parent perceptions on friendship quality were examined. In addition, this study examined the attitudes and behavioural intentions of peers toward individuals with disabilities. Three participants participated in the intervention over a four-week period. Training session took place at the participant’s home and at a local social club and generalisation settings took place at the participant’s after-school activity and/or school. A single case multiple baseline design was employed for each participant across settings. One individual and group session was conducted each week over a four-week period and participants were trained in initiating interactions and conversational skills. Direct observations were conducting over a six week period in the participant’s generalisation settings. All three participants showed gains in social interactions in at least one generalisation setting. Observations showed all three participants generalised atleast one skill to generalisation settings. Participants and parents showed similarities and differences in their perceptions of friendship qulity. Peers showed positive attitudes and behavioural intentions towards individuals with disabilities. It can be concluded that adolescents with disabilities can generalise social skills to other familiar environments, however time and opportunities can influence social interactions, friendships and attitudes.

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  • Non-invasive monitoring of peripheral oxygen extraction and perfusion using photoplethysmography.

    Khan, Musabbir (2016)

    Doctoral thesis
    University of Canterbury Library

    In the intensive care unit (ICU), cardiovascular disease and sepsis are major drivers of morbidity, mortality, and cost. Microcirculatory dysfunction during sepsis and cardiac failure is known to significantly impair perfusion in major organs and peripheral tissues, resulting in poor patient outcome if not corrected early. Arterial oxygen saturation (SaO2), venous oxygen saturation (SvO2), and their difference, or oxygen extraction (O2E), in association with blood flow, are key parameters necessary to assess tissue perfusion. Although, SaO2 can be reliably estimated by non invasive optical technologies, such as pulse oximetry in terms of SpO2, there are no established, easy, or non-invasive methods to assess SvO2, and thus O2E. Therefore, real-time, low-cost, and non-invasive assessment of SvO2, O2E, and blood flow could significantly advance the diagnosis, management, and of care sepsis or cardiovascular disease in the ICU. This research focuses on the development of a novel pulse oximeter based concept to non invasively and more completely assess tissue perfusion in peripheral extremities, such as the finger. A transmittance pulse oximeter sensor was used as the basis of a device to estimate and monitor peripheral SvO2, O2E, and blood flow changes. Robustness of perfusion assessment methods at various digit skin temperatures was also investigated to improve accuracy and define the limits of sensor accuracy. A custom built pulse oximeter (PO) device and graphical user interface (GUI) were developed to access and acquire all photoplethysmograph (PPG) signals, including the raw PPG signals. A two stage digital filter system was implemented to extract useful signals from the PPG. Time and frequency domain methods, including peak-trough detection algorithms, were developed to analyse the PPG data and estimate parameters, such as SaO2 and heart rate. This system was thus used as the basis for developing SvO2 and blood flow monitoring methods, and also the investigation of temperature effects on PPG measurements. A study was conducted with healthy adult volunteers (n = 20) to investigate the effect of a range of digit skin temperatures on pulse oximeter performance using a transmittance pulse oximeter sensor. It was hypothesized that cold digits can significantly reduce PPG signal quality and the resulting accuracy of SpO2 measurements, due to the likely reduction in blood flow of the periphery at these temperatures. PPG data were recorded at cold, normal, and baseline skin temperatures, using the PO system as well as a commercial pulse oximeter for reference. Results show warm skin temperatures improved PPG signal quality up to 64.4% compared to baseline, and provided SpO2 estimation of 96.5[96.1 – 97] % in the expected range for healthy adults. At baseline conditions, the majority of subjects showed a good PPG signal and expected SpO2 estimate of 95.8[93.2 – 96.8] %. PPG signal quality degraded significantly up to 54.0% at cold conditions and SpO2 estimates of 88.5[87.1 – 92.8] % were unreliable when compared to baseline. The main outcome is a tri-linear model quantifying PPG signal quality as a function of temperature, suggesting warm skin temperature conditions (approximately 33°C) should be maintained for reliable transmittance pulse oximetry. In circulatory dysfunction, peripheral blood flow can be reduced, adding error to assessment of SvO2 and O2E using typical models and assumptions. Relative volumetric blood flow change assessments using the PO sensor were performed in a study using 7 human adult volunteers. The signal amplitude of the high frequency PPG component, which is related to the pulsatile arterial blood flow, was used as an indicator of blood flow change. A vascular Doppler ultrasound sensor was used as a reference measurement. Changes in blood flow conditions were induced by a series of vascular occlusion tests. Good correlation (R2 = 0.69) and trend agreement was obtained between median PPG amplitude and Doppler ultrasound velocity, particularly at normal and clinically important low flow conditions. Thus, PPG amplitude monitoring can be a potential surrogate or alternative to vascular Doppler ultrasound based blood velocity monitoring, and can provide continuous and reliable measurements, ensuring flow conditions can be included in assessing SvO2. A novel artificial pulse generation system (APG) was developed to cause low frequency and low pressure modulations of venous blood in the finger using a pneumatic digit cuff. The APG system used a feedback controlled pressure regulator and solenoid valve to inflate/deflate the pressure cuff. This system was designed to exploit the significant arterial-venous compliance difference and make the peripheral venous blood pulsatile, while having negligible impact on arterial blood flow. Ten healthy human adults were recruited for proof-of-concept testing of this device. Modulation ratio (R) values derived from the artificially modulated PPG signals were used to estimate venous oxygen saturation (SpvO2) using an empirical calibration equation developed for arterial blood. Conventional empirical calibration model estimated arterial and venous saturations of 96.95[96.1 – 97.4] % and 93.15[91.1 – 93.9] % agree with published literature values. Median O2E was 3.6%, with a statistically significant and expected difference (p = 0.002) between pairs of measurements in each subject. The APG system in association with the pulse oximeter device to assess SvO2 was then validated in a clinical study with healthy adult volunteers (n = 8). A range of physiologically realistic SvO2 values were induced using vascular occlusion tests. Gold standard, arterial and venous blood gas measurements were used as reference measurements. Modulation ratios related to arterial and venous systems were determined using a frequency domain analysis of the PPG signals. A strong, linear correlation (R2 = 0.95) was found between estimated venous modulation ratio and measured SvO2, providing a calibration curve relating measured modulation ratio of venous blood to oxygen saturation. Median venous and arterial oxygen saturation accuracies from paired measurements were 0.29% and 0.65%, respectively, showing good accuracy of the pulse oximeter system. Investigations also revealed the empirical calibration model used to estimate SpaO2 cannot be used estimate SpvO2 because of the difference in optical absorption caused by artificial perturbations. In particular, there is a significant difference in gradient between the SpvO2 estimation model (SpvO2 = 111 – 40.5*R) and the empirical SpaO2 estimation model of (SpaO2 = 110 – 25*R). The main outcome of this study presents a novel pulse oximeter based calibration model that can be used to assess peripheral SvO2, and thus O2E, using the device developed in this work. Overall, this thesis successfully develops and demonstrates a non-invasive, pulse oximeter based method to assess peripheral tissue perfusion in terms of SaO2, SvO2, O2E and volumetric blood flow changes. This novel sensor may potentially detect peripheral perfusion alterations in real-time during microvascular and/or overall circulatory dysfunction, such as in sepsis or cardiac failure. Future work will follow the application of the novel sensor in a comprehensive clinical study with a larger, more diverse, cohort.

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  • Thriving after trauma : a study of posttraumatic growth amongst resilient residents of Christchurch, New Zealand, after the 2010 and 2011 earthquakes.

    Smith, Rebekah (2015)

    Doctoral thesis
    University of Canterbury Library

    Research on responses to trauma has historically focused on the negative repercussions of a struggle with adversity. However, more recently, researchers have begun to examine posttraumatic growth: the positive psychological change that emerges from the struggle with a potentially traumatic event. Associations have been found between posttraumatic growth and greater peritraumatic distress, greater objective severity of trauma exposure, greater perceived stressfulness of events, social support, female gender, cognitive and behavioural responses to trauma, and personality measures. Posttraumatic growth has been measured typically in individuals with varying levels of posttraumatic stress disorder symptoms and other psychological difficulties, such as depression and anxiety. Although some theory and research posits that higher resilience would prohibit posttraumatic growth, no studies have examined posttraumatic growth in a resilient sample. The Canterbury earthquake sequence of 2010 and 2011 involved potentially traumatic events that saw the community struggle with a variety of challenges. However, in the midst of earthquake destruction, some positive initiatives emerged, driven by locals. The Gap Filler project (using city spaces left empty from fallen buildings for art and interactive community projects) and the Student Volunteer Army (groups of volunteers coordinated to help others in need) are examples of this. In this context, it seemed likely that posttraumatic growth was occurring and might be seen in individuals who were coping well with challenges. Culture is theorised to influence the posttraumatic growth process (Calhoun, Cann, & Tedeschi, 2010), and the nature of the trauma undergone is also likely to influence the process of growth. The current thesis measures posttraumatic growth quantitatively and qualitatively in a New Zealand sample. It measures and describes posttraumatic growth in a resilient population after the earthquake sequence of 2010 and 2011 in Canterbury, New Zealand. Findings are used to test current models of posttraumatic growth for individuals coping well after trauma and to elaborate on mechanisms proposed by models such as the comprehensive model of posttraumatic growth (Calhoun et al., 2010) and the organismic valuing theory of growth through adversity (Joseph & Linley, 2005). Correlates of posttraumatic growth are examined and likely supporting factors of posttraumatic growth are identified for this population. Study 1 used quantitative analysis to explore correlates of posttraumatic growth and found that greater posttraumatic growth related to greater peritraumatic distress, greater perceived stressfulness of earthquake events, greater objective stressfulness of earthquake events, greater difficulty with stressful life events, less satisfaction with social support, and female gender. Findings from Study 1 give important detail about the nature of distress included in the comprehensive model of posttraumatic growth (Calhoun et al., 2010) for this population. Levels of posttraumatic growth were lower than those in North American studies but similar to those in a Chinese study. The current sample, however, showed lower endorsement of Relating to Others than the Chinese study, perhaps because of cultural differences. Study 2 used qualitative analysis to examine the experience of posttraumatic growth in the sample. The theme of ‘a greater sense of community’ was found and adds to the comprehensive model of posttraumatic growth, in that an expression of posttraumatic growth (a greater connection with others) can inform ongoing social processing in the posttraumatic growth process. Having a formal or informal role in earthquake recovery appeared to influence self-concept and reflection; this elaborates on the influence of role on reflection in Calhoun et al.’s model. Findings illustrate possible mechanisms of the organismic valuing process theorised by Joseph and Linley (2005). Implications include the importance of providing opportunities for individuals to take on a role after a crisis, encouraging them to act to respond to difficulties, and encouraging them to meet personal needs for relatedness, competence, and autonomy. Finding positive aspects to a difficult situation, as well as acknowledging adversity, can be supported in future to help individuals process their traumas. As a society, we can help individuals cope with adversity by providing ways they can meet their needs for relatedness, competence, and autonomy. Community groups likely provide opportunities for members to act in ways that meet such needs. This will allow them to effectively act to meet their needs in times of crisis.

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  • Non-slagging entrained flow gasification of pyrolysis oil from radiata pine woody biomass.

    Abdul Patah, Muhamad Fazly (2016)

    Doctoral thesis
    University of Canterbury Library

    A pilot scale non-slagging entrained flow (EF) gasification system was developed to gasify biomass pyrolysis oil using oxygen as the gasification agent. The pyrolysis oil was derived from New Zealand radiata pine wood chips through a fast pyrolysis process. The oil was fed into the system through an external mix twin-fluid atomizer which is capable of generating fine oil droplets after impact with the oxygen gas. Gasification was conducted at atmospheric pressure while the operation temperatures were dependent on the heat generated from partial combustion of pyrolysis oil with oxygen upon leaving the atomizer. Cold model experiments were first performed to investigate the effect of pyrolysis oil and gas flow rates on atomization performance. The use of external mix atomizer in this work is advantageous as it allows superior control of atomization performance by independent adjustments of pyrolysis oil and oxygen flow rates. Results from this cold model experiments show both flow rates of pyrolysis oil and oxygen gas have distinct influence on the resulted spray characteristics and consequently gasification performance. Increase in pyrolysis oil flow rate has negative influence on spray characteristics as larger droplet size and less uniform spray are generated. On the other hand, atomization at high gas flow rate substantially improves spray characteristics by production of more uniform spray and smaller droplets. The combined effect of pyrolysis oil and gas flow rates is reflected by the gas-to-fuel ratio (GFR) where higher GFR values indicate higher atomization performance and therefore better spray characteristics. After the cold model experiments, entrained flow gasification of pyrolysis oil were conducted to investigate effects of different gasification conditions on producer gas composition, gas yield, tar species distributions and total tar content in the producer gas. When equivalence ratio (ER) was increased during gasification at constant oxygen flow rate, concentrations of H2, CO and CO2 in the producer gas changed in parabolic trends, which is unique compared to linear relationships usually reported in the literature. Below the critical ER value, the H2 and CO concentrations increase while the CO2 concentration decreases with increasing equivalence ratio. However when the equivalence ratio exceeds the critical value, the opposite trends are observed. The critical ER during gasification at oxygen feeding rate of 900 L/h occurred at equivalence ratio of 0.3. At this condition, the maximum concentrations of H2 and CO were at 22 vol% and 36 vol% respectively while the minimum concentration of CO2 was measured at 33 vol%. The changes in producer gas trends with equivalence ratio relates to the continuous improvements in the spray characteristics and increase in the process residence time as the equivalence ratio increases. At constant oxygen flow rate, higher ER value is obtained by decreasing pyrolysis oil feeding into the system, which corresponds to higher GFR value thus better spray characteristics. The decline in pyrolysis oil feeding also results production of less producer gas which reduces its velocity and consequently increases the process residence time. Investigation on influence of increasing oxygen flow rate during gasification at constant ER was also performed in which the oxygen flow rate was varied between 600 L/h, 900 L/h, 1500 L/h and 3000 L/h in separate sets of experiments. Results from these experiments proved that at a given ER, gasification with high oxygen flow rate is highly desirable due to the substantial improvements in the oil spray characteristics and mixing behaviour that consequently leads to better overall reaction kinetics in the system. In addition to that, increase in the gasification temperature during gasification at high oxygen flow rates also help drive the system closer to equilibrium state which favours H2 and CO concentrations in the product. Increase of oxygen flow rate from 900 L/h to 1500L/h during gasification was observed to shift the critical ER value from 0.3 to 0.5 at which the maximum H2 and CO concentrations were also increased from 22 vol% to 28 vol% and from 36 vol% to 41 vol% respectively. On the other hand CO2 concentration declined from 33 vol% to 27 vol% when the oxygen flow rate was increased. In general, at high ER values, higher oxygen and pyrolysis oil flow rates favour producer gas quality with higher concentrations of H2 and CO but lower concentrations of CO2. However, at low ER values, the producer gas from gasification at higher oxygen and pyrolysis oil flow rates consists of lower concentrations of H2 and CO but higher concentration of CO2. As the residence time increases at increasing equivalence ratio, pyrolysis oil conversion improves more rapidly during gasification at 1500 L/h than that at 900 L/h thus giving more rapid growth in H2 and CO concentrations in the producer gas. These results are related to the effects of varying oxygen and pyrolysis oil flow rates on both spay characteristics and residence time. From analysis of tar in the producer gas, it was found that the total tar content in the producer gas decreased as the equivalence ratio was increased. In all cases investigated in this work, light polyaromatic hydrocarbon (PAH) compounds form the largest fractions of the tar components which accounts up to 78 wt% of the total tar in the producer gas. Detailed investigation into the tar individual species revealed naphthalene as the single most abundant tar species in the system which contributed as much as 36 wt% of the total tar in the producer gas. Results from this analysis also confirm that the methods used for tar sampling and analyses adopted in this work are capable of capturing and analysing tar compounds in the producer gas.

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  • Tax dispute systems design : international comparisons and the development of guidance from a New Zealand perspective.

    Jone, Melinda (2016)

    Doctoral thesis
    University of Canterbury Library

    Dispute systems design (DSD) refers to a deliberate effort to identify and improve the way an organisation addresses conflict by decisively and strategically arranging its dispute resolution processes. A number of principles have been put forward by various DSD practitioners for best practice in effective DSD. These principles emanate from the six fundamental DSD principles proposed by the seminal theorists Ury, Brett and Goldberg in Getting Disputes Resolved: Designing Systems to Cut the Costs of Conflict in 1988. To date, tax dispute resolution is an area that has not been extensively examined utilising DSD principles. However, with the recent trend of some tax authorities towards employing interests-based dispute resolution procedures, namely, various forms of alternative dispute resolution (ADR) processes, the application of DSD principles in the context of tax dispute resolution arguably warrants greater research. The purpose of this study is to develop the application of DSD principles in the particular context of tax dispute resolution. Utilising a comparative case study methodology, 14 DSD principles drawn from the literature have been used to evaluate the effectiveness of the design of the current tax dispute resolution processes of the jurisdictions of New Zealand (NZ), Australia, the United Kingdom (UK) and the United States (US). Through comparing the DSD evaluations conducted, this study has sought to develop a set of tax DSD principles to be adapted by tax administrations and used in either developing new or improving existing tax dispute resolution systems. Semi-structured interviews with 30 selected stakeholders in NZ have then been conducted in order to externally evaluate the tax DSD principles developed and also consider whether adaption of the principles is required in the context of the NZ tax dispute resolution procedures. The findings from the case studies indicate that the 14 DSD principles from the literature can generally be applied in the tax dispute resolution context without significant substantive modification. The interview findings suggest that the overarching design principle which must be borne in mind in the design of any tax dispute resolution system is that the system must be fair and perceived as fair. However, there is insufficient support from the interviews to justify any concrete changes being made to the tax DSD principles developed from the case studies. Thus, the interview findings are limited to the making of suggestions for certain modifications to the tax DSD principles potentially being made. Therefore, further research is necessary in order to confirm or refute the suggested changes. The interview findings further indicate that the tax DSD principles developed do not require adaptation specifically for NZ. Although, this may in part be due to the sample of participants interviewed being drawn only from NZ. Against the background of the overarching design principle of fairness, this study has a wide ranging applicability to tax administrations and their stakeholders in developing or improving their tax dispute resolution systems.

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