A conceptual framework for a theory of liquidity
- Authors: Culham, James
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: This study contributes to the understanding of liquidity in two ways. First, it considers the multifaceted nature of liquidity and its relationship with money. Second, it constructs a conceptual framework for a theory of liquidity. The first contribution is achieved by clarifying and categorising the various forms of liquidity to identify those overlooked by the existing literature. The second contribution consists of a realist critique of the literature on liquidity and money to highlight the strengths and weaknesses of each theoretical approach. The study reflects on the attempts to analyse liquidity using moneyless models of perfect barter with the assumption that every commodity exhibits perfect saleability; an assumption that removes any need for a medium of exchange and, moreover, crowds out all other forms of liquidity. It is concluded that, because liquidity is a social and monetary phenomenon, it cannot be analysed with models populated by a representative agent consuming a single commodity. Furthermore, this conclusion is not altered by the introduction of ‘financial frictions’, which are fundamentally at odds with the nature of money. Instead, the clarification of the nature of liquidity forms the basis for an interpretation of Keynes’s theory of liquidity preference that emphasises its reliance on liquidity in general, not money in particular. The study introduces the terms redemption liquidity and exchange liquidity to explain the trade-off that underpins the theory of liquidity preference. Properly interpreted, the theory of liquidity preference can then address many of the deficiencies prevalent in the dominant theories of the rate of interest. The study therefore has implications for monetary policy and asset pricing.
- Description: Doctor of Philosophy
- Authors: Culham, James
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: This study contributes to the understanding of liquidity in two ways. First, it considers the multifaceted nature of liquidity and its relationship with money. Second, it constructs a conceptual framework for a theory of liquidity. The first contribution is achieved by clarifying and categorising the various forms of liquidity to identify those overlooked by the existing literature. The second contribution consists of a realist critique of the literature on liquidity and money to highlight the strengths and weaknesses of each theoretical approach. The study reflects on the attempts to analyse liquidity using moneyless models of perfect barter with the assumption that every commodity exhibits perfect saleability; an assumption that removes any need for a medium of exchange and, moreover, crowds out all other forms of liquidity. It is concluded that, because liquidity is a social and monetary phenomenon, it cannot be analysed with models populated by a representative agent consuming a single commodity. Furthermore, this conclusion is not altered by the introduction of ‘financial frictions’, which are fundamentally at odds with the nature of money. Instead, the clarification of the nature of liquidity forms the basis for an interpretation of Keynes’s theory of liquidity preference that emphasises its reliance on liquidity in general, not money in particular. The study introduces the terms redemption liquidity and exchange liquidity to explain the trade-off that underpins the theory of liquidity preference. Properly interpreted, the theory of liquidity preference can then address many of the deficiencies prevalent in the dominant theories of the rate of interest. The study therefore has implications for monetary policy and asset pricing.
- Description: Doctor of Philosophy
Canonical dual finite element method for solving nonconvex mechanics and topology optimization
- Authors: Ali, Elaf
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text: false
- Description: Canonical duality theory (CDT) is a newly developed, potentially powerful method- ological theory which can transfer general multi-scale nonconvex/discrete problems in Rn to a unified convex dual problem in continuous space Rm with m
- Description: Doctor of Philosophy
Effective and efficient kernel-based image representations for classification and retrieval
- Authors: Karmakar, Priyabrata
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Image representation is a challenging task. In particular, in order to obtain better performances in different image processing applications such as video surveillance, autonomous driving, crime scene detection and automatic inspection, effective and efficient image representation is a fundamental need. The performance of these applications usually depends on how accurately images are classified into their corresponding groups or how precisely relevant images are retrieved from a database based on a query. Accuracy in image classification and precision in image retrieval depend on the effectiveness of image representation. Existing image representation methods have some limitations. For example, spatial pyramid matching, which is a popular method incorporating spatial information in image-level representation, has not been fully studied to date. In addition, the strengths of pyramid match kernel and spatial pyramid matching are not combined for better image matching. Kernel descriptors based on gradient, colour and shape overcome the limitations of histogram-based descriptors, but suffer from information loss, noise effects and high computational complexity. Furthermore, the combined performance of kernel descriptors has limitations related to computational complexity, higher dimensionality and lower effectiveness. Moreover, the potential of a global texture descriptor which is based on human visual perception has not been fully explored to date. Therefore, in this research project, kernel-based effective and efficient image representation methods are proposed to address the above limitations. An enhancement is made to spatial pyramid matching in terms of improved rotation invariance. This is done by investigating different partitioning schemes suitable to achieve rotation-invariant image representation and the proposal of a weight function for appropriate level contribution in image matching. In addition, the strengths of pyramid match kernel and spatial pyramid are combined to enhance matching accuracy between images. The existing kernel descriptors are modified and improved to achieve greater effectiveness, minimum noise effects, less dimensionality and lower computational complexity. A novel fusion approach is also proposed to combine the information related to all pixel attributes, before the descriptor extraction stage. Existing kernel descriptors are based only on gradient, colour and shape information. In this research project, a texture-based kernel descriptor is proposed by modifying an existing popular global texture descriptor. Finally, all the contributions are evaluated in an integrated system. The performances of the proposed methods are qualitatively and quantitatively evaluated on two to four different publicly available image databases. The experimental results show that the proposed methods are more effective and efficient in image representation than existing benchmark methods.
- Description: Doctor of Philosophy
- Authors: Karmakar, Priyabrata
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Image representation is a challenging task. In particular, in order to obtain better performances in different image processing applications such as video surveillance, autonomous driving, crime scene detection and automatic inspection, effective and efficient image representation is a fundamental need. The performance of these applications usually depends on how accurately images are classified into their corresponding groups or how precisely relevant images are retrieved from a database based on a query. Accuracy in image classification and precision in image retrieval depend on the effectiveness of image representation. Existing image representation methods have some limitations. For example, spatial pyramid matching, which is a popular method incorporating spatial information in image-level representation, has not been fully studied to date. In addition, the strengths of pyramid match kernel and spatial pyramid matching are not combined for better image matching. Kernel descriptors based on gradient, colour and shape overcome the limitations of histogram-based descriptors, but suffer from information loss, noise effects and high computational complexity. Furthermore, the combined performance of kernel descriptors has limitations related to computational complexity, higher dimensionality and lower effectiveness. Moreover, the potential of a global texture descriptor which is based on human visual perception has not been fully explored to date. Therefore, in this research project, kernel-based effective and efficient image representation methods are proposed to address the above limitations. An enhancement is made to spatial pyramid matching in terms of improved rotation invariance. This is done by investigating different partitioning schemes suitable to achieve rotation-invariant image representation and the proposal of a weight function for appropriate level contribution in image matching. In addition, the strengths of pyramid match kernel and spatial pyramid are combined to enhance matching accuracy between images. The existing kernel descriptors are modified and improved to achieve greater effectiveness, minimum noise effects, less dimensionality and lower computational complexity. A novel fusion approach is also proposed to combine the information related to all pixel attributes, before the descriptor extraction stage. Existing kernel descriptors are based only on gradient, colour and shape information. In this research project, a texture-based kernel descriptor is proposed by modifying an existing popular global texture descriptor. Finally, all the contributions are evaluated in an integrated system. The performances of the proposed methods are qualitatively and quantitatively evaluated on two to four different publicly available image databases. The experimental results show that the proposed methods are more effective and efficient in image representation than existing benchmark methods.
- Description: Doctor of Philosophy
Epigenetic modifications in essential hypertension
- Authors: Wise, Ingrid
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Background: Hypertension (HTN) is a complex, multifactorial, quantitative trait under polygenic control that affects more than one billion people globally. Despite advances in our understanding of the pathophysiology of HTN and the implementation of more effective treatment and prevention strategies, HTN remains one of the world’s great public health problems. The accepted inference from genome-wide association studies (GWAS) is that the genetic code lays the foundation for transcriptomic changes and in turn physiological change. On the other side of the coin, environmental factors (smoking, diet, chemical exposure) can in turn affect DNA itself in genes relevant to blood pressure (BP). Variation in epigenetic forms of modification may thus explain additional phenotypic variation in BP and provide new clues to the physiological processes influencing its regulation. DNA methylation is one of these epigenetic mechanisms responsible for changes to gene expression, activated by interaction with environmental triggers. DNA methylation is a reversible epigenetic modifier of specific dinucleotide sites called CpGs, which consists of a transfer of a methyl group derived from S-adenosyl-L-methionine to position five of a cytosine ring, forming 5mC. Pathophysiologically, the kidney is known as the key organ of BP regulation and one of the most important contributors to HTN. According to the hypothesis put forward by Guyton, over 40 years ago, the control of BP in the steady-state and longer-term is critically dependent on renal mechanisms. In fact, almost all monogenic forms of HTN are driven by rare mutations in genes involved in salt handling in the distal nephron. It is therefore crucial to understand kidney DNA methylation changes that may drive gene expression in kidney and lead to HTN. Hypothesis: The central hypothesis underpinning this PhD thesis is that alterations in kidney specific DNA methylation plays a fundamental role in modulating gene expression changes involved in the regulation of BP and pathophysiology of EH. Aims: This PhD thesis focuses on characterising the role of DNA methylation in the hypertensive kidney using array and RNA-sequencing methods. Three major aims are addressed: • Aim 1: To characterise blood and kidney global DNA methylation dynamics and its functional role in the hypertensive population (Chapter 3). • Aim 2: To determine the role of genome-wide, loci specific DNA methylation in the hypertensive human kidney (Chapter 4). • Aim 3: To understand the relationship between DNA methylation and differential expression of genes associated with BP and HTN in the human kidney (Chapter 5). Results: In Aim 1 global DNA methylation changes were characterised in peripheral blood leukocyte and kidney DNA of the hypertensive (HT) population using he ELISA method. We found no association between HTN diagnosis and global methylation percentage in either peripheral blood leukocytes or kidney DNA. However, a negative correlation was found between global methylation and diastolic blood pressure (DBP), yet this relationship was not evident after adjustment for the effect of antihypertensive medication. Furthermore, we investigated the sensitivity of ELISA-based global methylation detection by calculating the percentage of global methylation in kidney using array based methods; the results were similar, demonstrating no association between HTN diagnosis and median kidney methylation
- Description: Doctor of Philosophy
- Authors: Wise, Ingrid
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Background: Hypertension (HTN) is a complex, multifactorial, quantitative trait under polygenic control that affects more than one billion people globally. Despite advances in our understanding of the pathophysiology of HTN and the implementation of more effective treatment and prevention strategies, HTN remains one of the world’s great public health problems. The accepted inference from genome-wide association studies (GWAS) is that the genetic code lays the foundation for transcriptomic changes and in turn physiological change. On the other side of the coin, environmental factors (smoking, diet, chemical exposure) can in turn affect DNA itself in genes relevant to blood pressure (BP). Variation in epigenetic forms of modification may thus explain additional phenotypic variation in BP and provide new clues to the physiological processes influencing its regulation. DNA methylation is one of these epigenetic mechanisms responsible for changes to gene expression, activated by interaction with environmental triggers. DNA methylation is a reversible epigenetic modifier of specific dinucleotide sites called CpGs, which consists of a transfer of a methyl group derived from S-adenosyl-L-methionine to position five of a cytosine ring, forming 5mC. Pathophysiologically, the kidney is known as the key organ of BP regulation and one of the most important contributors to HTN. According to the hypothesis put forward by Guyton, over 40 years ago, the control of BP in the steady-state and longer-term is critically dependent on renal mechanisms. In fact, almost all monogenic forms of HTN are driven by rare mutations in genes involved in salt handling in the distal nephron. It is therefore crucial to understand kidney DNA methylation changes that may drive gene expression in kidney and lead to HTN. Hypothesis: The central hypothesis underpinning this PhD thesis is that alterations in kidney specific DNA methylation plays a fundamental role in modulating gene expression changes involved in the regulation of BP and pathophysiology of EH. Aims: This PhD thesis focuses on characterising the role of DNA methylation in the hypertensive kidney using array and RNA-sequencing methods. Three major aims are addressed: • Aim 1: To characterise blood and kidney global DNA methylation dynamics and its functional role in the hypertensive population (Chapter 3). • Aim 2: To determine the role of genome-wide, loci specific DNA methylation in the hypertensive human kidney (Chapter 4). • Aim 3: To understand the relationship between DNA methylation and differential expression of genes associated with BP and HTN in the human kidney (Chapter 5). Results: In Aim 1 global DNA methylation changes were characterised in peripheral blood leukocyte and kidney DNA of the hypertensive (HT) population using he ELISA method. We found no association between HTN diagnosis and global methylation percentage in either peripheral blood leukocytes or kidney DNA. However, a negative correlation was found between global methylation and diastolic blood pressure (DBP), yet this relationship was not evident after adjustment for the effect of antihypertensive medication. Furthermore, we investigated the sensitivity of ELISA-based global methylation detection by calculating the percentage of global methylation in kidney using array based methods; the results were similar, demonstrating no association between HTN diagnosis and median kidney methylation
- Description: Doctor of Philosophy
Investigating the impact of participation in alternative education from a positive youth development perspective : A case study of the School for Student Leadership
- Authors: Joyce, Susan
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: The School for Student Leadership (SSL) has existed since 2001 as an alternative residential educational setting for Year 9 students in Victoria, Australia. It was designed in response to growing calls for more effective ways of engaging middle school students. A review of the literature illustrated a dearth of research regarding alternative programs and schools, particularly from a positive youth development (PYD) perspective, and relating to long term effects of participation. This study investigated student participants’ perceived development in relation to the Five Cs - Confidence, Competence, Character, Connection and Care, concepts derived from the framework of PYD. It also examined differences in perceptions of students attending a shorter five-week program, compared to the standard nine-week program, as well as differences between male and female participants. This case study was undertaken utilising a mixed methods approach, using pre and post program surveys and interviews. Between 2013 and 2014, 385 students were surveyed and 58 interviews conducted over nine program offerings. The participants were then followed up one year post program, with 172 surveys returned and 14 interviews conducted. With the assistance of computer software programs, both the quantitative and qualitative data was analysed and then triangulated to form the findings. Participants’ ratings for each of the Five Cs were higher at the end of the program, and effect sizes, though generally small, when combined with the qualitative data indicated the program as having a significant positive impact, although this diminished slightly one year post program. Little discernible difference was found between the five- and the nine-week programs, and only slight differences between the two genders. The set of recommendations that emanated from this research should be of assistance for both the SSL and other schools, particularly in relation to enhancing attributes such as the Five Cs.
- Description: Doctor of Philosophy
- Authors: Joyce, Susan
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: The School for Student Leadership (SSL) has existed since 2001 as an alternative residential educational setting for Year 9 students in Victoria, Australia. It was designed in response to growing calls for more effective ways of engaging middle school students. A review of the literature illustrated a dearth of research regarding alternative programs and schools, particularly from a positive youth development (PYD) perspective, and relating to long term effects of participation. This study investigated student participants’ perceived development in relation to the Five Cs - Confidence, Competence, Character, Connection and Care, concepts derived from the framework of PYD. It also examined differences in perceptions of students attending a shorter five-week program, compared to the standard nine-week program, as well as differences between male and female participants. This case study was undertaken utilising a mixed methods approach, using pre and post program surveys and interviews. Between 2013 and 2014, 385 students were surveyed and 58 interviews conducted over nine program offerings. The participants were then followed up one year post program, with 172 surveys returned and 14 interviews conducted. With the assistance of computer software programs, both the quantitative and qualitative data was analysed and then triangulated to form the findings. Participants’ ratings for each of the Five Cs were higher at the end of the program, and effect sizes, though generally small, when combined with the qualitative data indicated the program as having a significant positive impact, although this diminished slightly one year post program. Little discernible difference was found between the five- and the nine-week programs, and only slight differences between the two genders. The set of recommendations that emanated from this research should be of assistance for both the SSL and other schools, particularly in relation to enhancing attributes such as the Five Cs.
- Description: Doctor of Philosophy
Negotiating policy - renegotiating practice : Understanding language, literacy and numeracy teachers' professional identities within discursive weather systems
- Authors: Krusche, Julianne
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis examines the professional identities of teachers in light of Australian vocational educational policy reform since the late 1980s. Although the reform has been national, this study is located within Victoria. It is specifically interested in the professional identities of Language, Literacy and Numeracy (LLN) teachers who work within the Vocational Education and Training sector. This study brings the voices of LLN specialists to the forefront. Poststructural theory, with particular emphasis on the work of Michel Foucault and narrative inquiry, is used to make sense of these voices, collectively known as the ‘voice of practice’. This study treats professional identity as a multiple term encompassing a range of assigned roles and chosen identities; as such, it argues that professional identity should be seen as fluid and dynamic and as something that continues to evolve. The teachers involved in this study actively negotiated various discourses related to the shaping of professional identity. The effects of this were threefold: LLN teachers ascribed to certain identity positions in line with government policy and institute directives; they preserved other identities; and they forged new identities based on opportunism and a resistance to policy discourse. While there has been a decline in the Adult and Community Education voice in policy development, within practice, this study found that teachers have retained a voice through the maintenance and creation of teaching practices that sit outside policy. Further, this study found that although numerous stakeholders invest in the provision of LLN, it is learners who hold a lot of the power; indeed, the needs of learners, feedback from learners and their transformative learning experiences are the primary drivers in teacher motivation and identity. Finally, this study found a misalignment between policy discourse and the voice of practice that requires attention if LLN policies are to be successfully implemented.
- Description: Doctor of Philosophy
- Authors: Krusche, Julianne
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis examines the professional identities of teachers in light of Australian vocational educational policy reform since the late 1980s. Although the reform has been national, this study is located within Victoria. It is specifically interested in the professional identities of Language, Literacy and Numeracy (LLN) teachers who work within the Vocational Education and Training sector. This study brings the voices of LLN specialists to the forefront. Poststructural theory, with particular emphasis on the work of Michel Foucault and narrative inquiry, is used to make sense of these voices, collectively known as the ‘voice of practice’. This study treats professional identity as a multiple term encompassing a range of assigned roles and chosen identities; as such, it argues that professional identity should be seen as fluid and dynamic and as something that continues to evolve. The teachers involved in this study actively negotiated various discourses related to the shaping of professional identity. The effects of this were threefold: LLN teachers ascribed to certain identity positions in line with government policy and institute directives; they preserved other identities; and they forged new identities based on opportunism and a resistance to policy discourse. While there has been a decline in the Adult and Community Education voice in policy development, within practice, this study found that teachers have retained a voice through the maintenance and creation of teaching practices that sit outside policy. Further, this study found that although numerous stakeholders invest in the provision of LLN, it is learners who hold a lot of the power; indeed, the needs of learners, feedback from learners and their transformative learning experiences are the primary drivers in teacher motivation and identity. Finally, this study found a misalignment between policy discourse and the voice of practice that requires attention if LLN policies are to be successfully implemented.
- Description: Doctor of Philosophy
Physical activity promotion in physiotherapy practice
- Authors: Kunstler, Breanne
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Australian physiotherapists promote non-treatment physical activity, which is physical activity used to improve or maintain general health, to patients with musculoskeletal conditions. However, it is unclear how physiotherapists promote non-treatment physical activity and the behaviour change techniques they use to do this. This thesis used four studies to: (i) review the efficacy of physiotherapist-led physical activity interventions; (ii) investigate the factors that influence physiotherapists’ choice to promote non-treatment physical activity; and (iii) identify the behaviour change techniques that private practice and outpatient physiotherapists use to promote non-treatment physical activity. Two systematic reviews identified that physiotherapist-led physical activity interventions are efficacious. However, effects were small and not maintained. Additionally, physiotherapists only used a small number of behaviour change techniques when promoting physical activity. National survey and interview studies were used to identify the factors that influence physiotherapists’ choice to promote non-treatment physical activity. The survey found that having poor knowledge of how to promote non-treatment physical activity, prioritising other patient problems before non-treatment physical activity and using promotion methods that were not compatible with daily practice significantly and independently reduced the odds of physiotherapists promoting non-treatment physical activity. Interpretative phenomenological analysis was used to design interviews that showed that having a perceived inability to motivate an unmotivated patient and believing that patients expect hands-on therapy instead of non-treatment physical activity promotion complicated treatment choices. The behaviour change techniques Australian physiotherapists used to promote non-treatment physical activity were compared to those used to encourage adherence to rehabilitation exercises in the survey too. The survey found that physiotherapists used similar behaviour change techniques to promote non-treatment physical activity and encourage adherence to rehabilitation exercises. This thesis provides clinicians and researchers with an understanding of the factors that influence Australian physiotherapists’ decision to promote non-treatment physical activity and the behaviour change techniques they use.
- Description: Doctor of Philosophy
- Authors: Kunstler, Breanne
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Australian physiotherapists promote non-treatment physical activity, which is physical activity used to improve or maintain general health, to patients with musculoskeletal conditions. However, it is unclear how physiotherapists promote non-treatment physical activity and the behaviour change techniques they use to do this. This thesis used four studies to: (i) review the efficacy of physiotherapist-led physical activity interventions; (ii) investigate the factors that influence physiotherapists’ choice to promote non-treatment physical activity; and (iii) identify the behaviour change techniques that private practice and outpatient physiotherapists use to promote non-treatment physical activity. Two systematic reviews identified that physiotherapist-led physical activity interventions are efficacious. However, effects were small and not maintained. Additionally, physiotherapists only used a small number of behaviour change techniques when promoting physical activity. National survey and interview studies were used to identify the factors that influence physiotherapists’ choice to promote non-treatment physical activity. The survey found that having poor knowledge of how to promote non-treatment physical activity, prioritising other patient problems before non-treatment physical activity and using promotion methods that were not compatible with daily practice significantly and independently reduced the odds of physiotherapists promoting non-treatment physical activity. Interpretative phenomenological analysis was used to design interviews that showed that having a perceived inability to motivate an unmotivated patient and believing that patients expect hands-on therapy instead of non-treatment physical activity promotion complicated treatment choices. The behaviour change techniques Australian physiotherapists used to promote non-treatment physical activity were compared to those used to encourage adherence to rehabilitation exercises in the survey too. The survey found that physiotherapists used similar behaviour change techniques to promote non-treatment physical activity and encourage adherence to rehabilitation exercises. This thesis provides clinicians and researchers with an understanding of the factors that influence Australian physiotherapists’ decision to promote non-treatment physical activity and the behaviour change techniques they use.
- Description: Doctor of Philosophy
Spatial epidemiological investigation of sport and leisure injuries in Victoria, Australia
- Authors: Singh, Himalaya
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Sport and leisure injuries are recognised as a public health issue in Australia. Despite the many health benefits associated with sport and leisure participation, there is a risk of sustaining injury during participation. To keep Australia active, there is a critical need to prevent injury occurrence. Epidemiological investigations in sport and leisure injuries have been largely examined by grouping of sports, age groups, sex and level of play. In addition, intrinsic (person-level) factors have been considered, such as strength, flexibility or previous injury history. These factors may not be sufficient to identify injury burden or prevent an increase in injury incidences. In the broader injury literature (e.g., road traffic crashes or drowning), it is known that injuries often cluster within specific places (i.e., road intersections or bodies of water). These specific geographic locations may also relate to sport and leisure injuries (e.g., sports grounds or facilities). Similarly, population-level factors such as socio-economic status or cultural groups within an area could influence the types of sports and leisure activities people participate in and consequently, the injuries that occur. A review presented in this PhD thesis revealed that there is very limited sport and leisure injury epidemiological information from a geographical perspective. To address this gap, and determine whether there is a spatial pattern in sport/leisure injuries, the aim of this PhD was to examine the geospatial distribution of sport/leisure injury hospitalisations and their association with a broad range of social and economic characteristics. This thesis uses spatial epidemiological methods to answer questions such as ‘Where do sports and leisure injuries occur?’ and ‘In whom do sports/leisure injuries occur?’ The main chapters present the results of the application of spatial epidemiological methods to describe the problem, to test hypotheses and to explore associations with possible explanatory variables. The findings showed a significant variation across metropolitan, regional and rural areas in the pattern and clustering of injuries when examining different sports, age groups and other variables such as education level. A secondary aim of this thesis was to consider the dissemination of sport and injury epidemiological data. As emphasised in the literature, there is limited spatial epidemiological information available to decision-makers and key stakeholders. At best, descriptive maps might be included in a report or research paper. However, these are static and limited to the results that the author chooses to present. Therefore, an important output from this PhD is a web-GIS application that has been specifically built to enable the exploratory analysis of sport/leisure injuries in Victoria. Sport and leisure injury prevention strategies and policy development relies on information about where, when, to whom and how sport/leisure injuries occur. This thesis demonstrates that a spatial epidemiological approach is an important and novel way to address epidemiological questions from a geographical perspective.
- Description: Doctor of Philosophy
- Authors: Singh, Himalaya
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Sport and leisure injuries are recognised as a public health issue in Australia. Despite the many health benefits associated with sport and leisure participation, there is a risk of sustaining injury during participation. To keep Australia active, there is a critical need to prevent injury occurrence. Epidemiological investigations in sport and leisure injuries have been largely examined by grouping of sports, age groups, sex and level of play. In addition, intrinsic (person-level) factors have been considered, such as strength, flexibility or previous injury history. These factors may not be sufficient to identify injury burden or prevent an increase in injury incidences. In the broader injury literature (e.g., road traffic crashes or drowning), it is known that injuries often cluster within specific places (i.e., road intersections or bodies of water). These specific geographic locations may also relate to sport and leisure injuries (e.g., sports grounds or facilities). Similarly, population-level factors such as socio-economic status or cultural groups within an area could influence the types of sports and leisure activities people participate in and consequently, the injuries that occur. A review presented in this PhD thesis revealed that there is very limited sport and leisure injury epidemiological information from a geographical perspective. To address this gap, and determine whether there is a spatial pattern in sport/leisure injuries, the aim of this PhD was to examine the geospatial distribution of sport/leisure injury hospitalisations and their association with a broad range of social and economic characteristics. This thesis uses spatial epidemiological methods to answer questions such as ‘Where do sports and leisure injuries occur?’ and ‘In whom do sports/leisure injuries occur?’ The main chapters present the results of the application of spatial epidemiological methods to describe the problem, to test hypotheses and to explore associations with possible explanatory variables. The findings showed a significant variation across metropolitan, regional and rural areas in the pattern and clustering of injuries when examining different sports, age groups and other variables such as education level. A secondary aim of this thesis was to consider the dissemination of sport and injury epidemiological data. As emphasised in the literature, there is limited spatial epidemiological information available to decision-makers and key stakeholders. At best, descriptive maps might be included in a report or research paper. However, these are static and limited to the results that the author chooses to present. Therefore, an important output from this PhD is a web-GIS application that has been specifically built to enable the exploratory analysis of sport/leisure injuries in Victoria. Sport and leisure injury prevention strategies and policy development relies on information about where, when, to whom and how sport/leisure injuries occur. This thesis demonstrates that a spatial epidemiological approach is an important and novel way to address epidemiological questions from a geographical perspective.
- Description: Doctor of Philosophy
Teachers' emotional intelligence as a predisposition for discrimiation against students with severe emotional and behavioural disorders
- Authors: Metaxas, Melinda
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Students with Emotional Behavioural Disorders (EBD) are among the most challenging students to teach. Personality Trait Theory predicts teachers’ level of Emotional Intelligence (EI) would affect their cognitive-affective-behavioural reactions towards students with EBDs, and influence level of academic achievement and difficult behaviour of these students. This research explores which teachers are more predisposed to discriminate against EBD students, and identifies the most ‘effective’, supportive EI teacher traits. Underlying psychological processes, such as genetic EI make-up of teachers, may prove to be most valuable in determining whether more practical strategies for dealing with students’ behaviour/emotions are effectively applied and successful. An Attribution Model framework helped assess teacher reactions towards students. Two hundred and sixty one teachers from 51 Victorian schools participated in the study by completing self-report questionnaires, including the Trait Emotional Intelligence Questionnaire. A quantitative survey methodology used vignettes, with each school contact person randomly giving 50/50 surveys to their teachers (depicting a student with either mild or severe EBD symptoms). Pathway analysis revealed that teachers with higher EI reported less stigmatising and punitive intentions and likely greater helping behaviours. A new EI Process Model of Stigmatisation was proposed to measure teacher reactions through an affective-cognitive-behavioural sequence, rather than a cognitive-affective-behavioural sequence. Teachers’ EI levels also related to their own levels of psychological distress and/or compassion stress, which influenced likely helping or punitive outcomes. Despite behavioural severity of EBD students, teachers higher in EI still indicate more supportive helping behaviours. Specifically-identified ‘ideal’ teacher EI traits should lead to greater helping and be psychologically beneficial to both students and teachers. These results assisted development of an assessment tool (ASET – Assessment Screen for Emotionally Intelligent Teachers), which lays a sound foundation for schools and others to profile or recruit teachers with best ‘qualities’ to effectively teach students EBD students.
- Description: Doctor of Philosophy
- Authors: Metaxas, Melinda
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Students with Emotional Behavioural Disorders (EBD) are among the most challenging students to teach. Personality Trait Theory predicts teachers’ level of Emotional Intelligence (EI) would affect their cognitive-affective-behavioural reactions towards students with EBDs, and influence level of academic achievement and difficult behaviour of these students. This research explores which teachers are more predisposed to discriminate against EBD students, and identifies the most ‘effective’, supportive EI teacher traits. Underlying psychological processes, such as genetic EI make-up of teachers, may prove to be most valuable in determining whether more practical strategies for dealing with students’ behaviour/emotions are effectively applied and successful. An Attribution Model framework helped assess teacher reactions towards students. Two hundred and sixty one teachers from 51 Victorian schools participated in the study by completing self-report questionnaires, including the Trait Emotional Intelligence Questionnaire. A quantitative survey methodology used vignettes, with each school contact person randomly giving 50/50 surveys to their teachers (depicting a student with either mild or severe EBD symptoms). Pathway analysis revealed that teachers with higher EI reported less stigmatising and punitive intentions and likely greater helping behaviours. A new EI Process Model of Stigmatisation was proposed to measure teacher reactions through an affective-cognitive-behavioural sequence, rather than a cognitive-affective-behavioural sequence. Teachers’ EI levels also related to their own levels of psychological distress and/or compassion stress, which influenced likely helping or punitive outcomes. Despite behavioural severity of EBD students, teachers higher in EI still indicate more supportive helping behaviours. Specifically-identified ‘ideal’ teacher EI traits should lead to greater helping and be psychologically beneficial to both students and teachers. These results assisted development of an assessment tool (ASET – Assessment Screen for Emotionally Intelligent Teachers), which lays a sound foundation for schools and others to profile or recruit teachers with best ‘qualities’ to effectively teach students EBD students.
- Description: Doctor of Philosophy
The contribution of silverfish (insecta: zygentoma) to Australian invertebrate biodiversity and endemism
- Authors: Smith, Graeme
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Silverfish (Order Zygentoma) are quite abundant in Australia but have been largely overlooked. This thesis examines the biodiversity of the Australian fauna at the level of genus, describing at least one representative species from each named genus and some new genera. The endemism of the fauna is evaluated and likely zoogeographic origins proposed. Over 4000 specimens were examined, either collected by the author, borrowed from or examined within museum collections or supplied by organisations and individuals conducting fauna surveys. Twenty- seven new native species are described and two redescribed, bringing the number of named species recorded in Australia to 74. Five new genera are described and four additional genera recorded in Australia for the first time including autochthonous representatives of three subfamilies previously unrecognised as native to Australia (Acrotelsatinae, Lepismatinae and Coletiniinae). No representatives of the families Maindroniidae, Tricholepidiidae and Protrinemuridae were found. The subfamily Acrotelsatinae was redefined following a revision of the enigmatic genus Anisolepisma Paclt, 1967 with the unique structure of the thoracic sterna identified as diagnostic for the subfamily. Contrary to existing opinion, it is suggested that this is a fundamentally different and plesiomorphic character, rather than an apomorphic reduction of the free thoracic sterna. A monograph of the Australian Zygentoma is presented, including a summary of the biology of the order, a key to and diagnoses of the genera, as well as information on the known habitat and distribution of each genus and a discussion of their zoogeography. At the suprageneric level the fauna is less diverse than seen in other zoogeographic regions but appears to be rich in the number of species. The fauna displays a high degree of endemism with 91% of described species and 52% of the genera known only from Australia. Some genera appear to be ancient and probably represent a Pangean element in the Australian fauna. Others appear to have emerged in the late Jurassic when Africa was still joined to Gondwana, while some may have appeared in the Cretaceous or Palaeocene when Australia and South America were connected to Gondwana. More recent links with the Asian fauna are limited and there appears to be no widespread highly mobile global species other than the six introduced anthropophilic species. Maps of the worldwide distribution records extracted from the taxonomic literature are used to discuss the zoogeography of the subfamilies and tribes present in Australia. Molecular data using two mitochondrial genes (16S and COI) as well as a nuclear gene (28S) were compared with detailed morphological and morphometric analysis to examine populations initially determined as Heterolepisma sclerophylla or close to it. Distances of 0.9– 1.8% or greater in 28S, and 7.2–14% in COI were associated with morphologically distinct species. A southern Queensland population was found to be genetically, morphometrically and morphologically very distinct from those collected in NSW and was described as new (Heterolepisma sp. B). Six well-defined barcode clusters (“lineages”) were identified within the NSW populations, each with >4% divergence in COI sequences and each geographically restricted. Intracluster divergences are also large, and despite the well-supported phylogeny no clear “barcode gap” (distinction between intracluster and intercluster distances) was found for three of the six NSW populations. The 28S data distinguished only four of the six COI clusters from NSW with essentially no variation within each cluster. The 28S data generally aligned well with morphological evidence, clearly identifying Heterolepisma sp. B as a distinct species, and supporting also the description of Heterolepisma sp. A even though it only appears to differ from H. sclerophylla in the number of styli. Similar genetic distances are observed in 28S data for H. sclerophylla populations from North Nowra, Glenbrook/Burralow/Nattai and Megalong, however the Broulee and Wellington populations have identical 28S sequences. The low levels of variation in 28S sequences between NSW populations accord with the lack of unambiguous morphological differences.
- Description: Doctor of Philosophy
- Authors: Smith, Graeme
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Silverfish (Order Zygentoma) are quite abundant in Australia but have been largely overlooked. This thesis examines the biodiversity of the Australian fauna at the level of genus, describing at least one representative species from each named genus and some new genera. The endemism of the fauna is evaluated and likely zoogeographic origins proposed. Over 4000 specimens were examined, either collected by the author, borrowed from or examined within museum collections or supplied by organisations and individuals conducting fauna surveys. Twenty- seven new native species are described and two redescribed, bringing the number of named species recorded in Australia to 74. Five new genera are described and four additional genera recorded in Australia for the first time including autochthonous representatives of three subfamilies previously unrecognised as native to Australia (Acrotelsatinae, Lepismatinae and Coletiniinae). No representatives of the families Maindroniidae, Tricholepidiidae and Protrinemuridae were found. The subfamily Acrotelsatinae was redefined following a revision of the enigmatic genus Anisolepisma Paclt, 1967 with the unique structure of the thoracic sterna identified as diagnostic for the subfamily. Contrary to existing opinion, it is suggested that this is a fundamentally different and plesiomorphic character, rather than an apomorphic reduction of the free thoracic sterna. A monograph of the Australian Zygentoma is presented, including a summary of the biology of the order, a key to and diagnoses of the genera, as well as information on the known habitat and distribution of each genus and a discussion of their zoogeography. At the suprageneric level the fauna is less diverse than seen in other zoogeographic regions but appears to be rich in the number of species. The fauna displays a high degree of endemism with 91% of described species and 52% of the genera known only from Australia. Some genera appear to be ancient and probably represent a Pangean element in the Australian fauna. Others appear to have emerged in the late Jurassic when Africa was still joined to Gondwana, while some may have appeared in the Cretaceous or Palaeocene when Australia and South America were connected to Gondwana. More recent links with the Asian fauna are limited and there appears to be no widespread highly mobile global species other than the six introduced anthropophilic species. Maps of the worldwide distribution records extracted from the taxonomic literature are used to discuss the zoogeography of the subfamilies and tribes present in Australia. Molecular data using two mitochondrial genes (16S and COI) as well as a nuclear gene (28S) were compared with detailed morphological and morphometric analysis to examine populations initially determined as Heterolepisma sclerophylla or close to it. Distances of 0.9– 1.8% or greater in 28S, and 7.2–14% in COI were associated with morphologically distinct species. A southern Queensland population was found to be genetically, morphometrically and morphologically very distinct from those collected in NSW and was described as new (Heterolepisma sp. B). Six well-defined barcode clusters (“lineages”) were identified within the NSW populations, each with >4% divergence in COI sequences and each geographically restricted. Intracluster divergences are also large, and despite the well-supported phylogeny no clear “barcode gap” (distinction between intracluster and intercluster distances) was found for three of the six NSW populations. The 28S data distinguished only four of the six COI clusters from NSW with essentially no variation within each cluster. The 28S data generally aligned well with morphological evidence, clearly identifying Heterolepisma sp. B as a distinct species, and supporting also the description of Heterolepisma sp. A even though it only appears to differ from H. sclerophylla in the number of styli. Similar genetic distances are observed in 28S data for H. sclerophylla populations from North Nowra, Glenbrook/Burralow/Nattai and Megalong, however the Broulee and Wellington populations have identical 28S sequences. The low levels of variation in 28S sequences between NSW populations accord with the lack of unambiguous morphological differences.
- Description: Doctor of Philosophy
The influence of controlled fire on the mobilization of Potentially Toxic Elements (PTE) in a mined landscape : Implications for land management and environmental health
- Authors: Abraham, Joji
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Controlled fires conducted in fire prone areas are an efficient and economic option to reduce the frequency and intensity of wild fires that result in damage to human property, infrastructure and ecosystems. However, in a similar way to wild fires, controlled fires affect many of the physical and bio-geochemical properties of the forest soil, and may remobilize Potentially Toxic Elements (PTE) from vegetation and soil organic matter. The objective of this study is to investigate the mobilization of PTEs in a mined landscape after a controlled fire and to describe their temporal variations in concentrations. Soil samples were collected two days before and two days after the controlled fire, at the end of each season, and after a major rainfall in September 2016, from a legacy mine site in Maldon, Central Victoria, Australia, and analysed for PTE concentrations. The results revealed PTE mobility after the controlled fire, and most of the PTEs (As, Cd, Cu, Mn, and Zn) evidenced an increase in concentration (1.2, 1.5, 1.1, 2.9, and 1.7 times respectively) and other PTEs (Hg, Cr and Pb) shown a decrease (1.4, 1.1 and 1.1 times respectively) immediately after the fire. The increase in PTE concentration immediately after the fire is postulated to be associated with the addition of PTE enriched ash to the soil and the reduction is due to the volatilization of elements during fire. The PTEs, which increased their concentrations immediately after the fire show a temporal decrease in concentration in the post-fire soil environment due to the removal of ash and surface soil by rainfall runoff, leaching and wind activity. However, Hg shows an increase in concentration after the major rainfall event. Although, median concentrations of As, Hg, Pb, Cu and Zn exceeded the Australian and Victorian top soil averages, only As and Hg are considered to be a risk to human and aquatic ecosystems health due to their elevated concentration and toxicity. Climate change and the resulting projection for increased forest fire frequency illustrates a growing concern given the expected concomitant increase in PTE mobilization. Preparing appropriate land and water management strategies, and addressing environmental health practice and policy, specifically at the legacy mining areas require a review. This study highlights the significant risk these sites pose.
- Description: Doctor of Philosophy
- Authors: Abraham, Joji
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Controlled fires conducted in fire prone areas are an efficient and economic option to reduce the frequency and intensity of wild fires that result in damage to human property, infrastructure and ecosystems. However, in a similar way to wild fires, controlled fires affect many of the physical and bio-geochemical properties of the forest soil, and may remobilize Potentially Toxic Elements (PTE) from vegetation and soil organic matter. The objective of this study is to investigate the mobilization of PTEs in a mined landscape after a controlled fire and to describe their temporal variations in concentrations. Soil samples were collected two days before and two days after the controlled fire, at the end of each season, and after a major rainfall in September 2016, from a legacy mine site in Maldon, Central Victoria, Australia, and analysed for PTE concentrations. The results revealed PTE mobility after the controlled fire, and most of the PTEs (As, Cd, Cu, Mn, and Zn) evidenced an increase in concentration (1.2, 1.5, 1.1, 2.9, and 1.7 times respectively) and other PTEs (Hg, Cr and Pb) shown a decrease (1.4, 1.1 and 1.1 times respectively) immediately after the fire. The increase in PTE concentration immediately after the fire is postulated to be associated with the addition of PTE enriched ash to the soil and the reduction is due to the volatilization of elements during fire. The PTEs, which increased their concentrations immediately after the fire show a temporal decrease in concentration in the post-fire soil environment due to the removal of ash and surface soil by rainfall runoff, leaching and wind activity. However, Hg shows an increase in concentration after the major rainfall event. Although, median concentrations of As, Hg, Pb, Cu and Zn exceeded the Australian and Victorian top soil averages, only As and Hg are considered to be a risk to human and aquatic ecosystems health due to their elevated concentration and toxicity. Climate change and the resulting projection for increased forest fire frequency illustrates a growing concern given the expected concomitant increase in PTE mobilization. Preparing appropriate land and water management strategies, and addressing environmental health practice and policy, specifically at the legacy mining areas require a review. This study highlights the significant risk these sites pose.
- Description: Doctor of Philosophy
A financial stress index to model and forecast financial stress in Australia
- Authors: Mukulu, Sandra
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: The series of financial crises that cascaded through and rocked much of the world over the past decade created opportunities to draw meaning from the pattern of countries succumbing to crisis and those who appear to be wholly or partially immune. This thesis examines the case of Australia, a developed country that has seldom experienced an endogenous crisis in the last few decades, but has experienced crisis by contagion. This study designs a financial stress index to measure and forecast the health of the Australian economy and proposes a custom-made stress index to: Gauge the potential for a crisis; and Signal when a timely intervention may minimise fear and contagion losses in the Australian financial market. Financial and economic data is used to design indicators for stress in the banking sector and equity, currency and bond markets. Further, this study explores how movements in equity markets of key trading partners of Australia can be used to predict movements in the Australian equity market. The variance-equal weights (VEW) and principal components approach (PCA) are used to subsume 22 stress indicators into a composite stress index. The VEW and PCA stress indexes were examined to determine monitoring and their forecasting capabilities. It was found that the VEW stress index performed better than the PCA stress index, because it provided more consistent estimates for the level of Australian financial stress. Although, both models show some promise, each model fell short of giving adequate forecasts in financial stress especially at the peak time of the 2007-2009 GFC. Thus, more research is needed to understand the complex nature of financial crisis, how crises develop and the techniques that can be used to predict the onset of financial crises.
- Description: Doctor of Philosophy
- Authors: Mukulu, Sandra
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: The series of financial crises that cascaded through and rocked much of the world over the past decade created opportunities to draw meaning from the pattern of countries succumbing to crisis and those who appear to be wholly or partially immune. This thesis examines the case of Australia, a developed country that has seldom experienced an endogenous crisis in the last few decades, but has experienced crisis by contagion. This study designs a financial stress index to measure and forecast the health of the Australian economy and proposes a custom-made stress index to: Gauge the potential for a crisis; and Signal when a timely intervention may minimise fear and contagion losses in the Australian financial market. Financial and economic data is used to design indicators for stress in the banking sector and equity, currency and bond markets. Further, this study explores how movements in equity markets of key trading partners of Australia can be used to predict movements in the Australian equity market. The variance-equal weights (VEW) and principal components approach (PCA) are used to subsume 22 stress indicators into a composite stress index. The VEW and PCA stress indexes were examined to determine monitoring and their forecasting capabilities. It was found that the VEW stress index performed better than the PCA stress index, because it provided more consistent estimates for the level of Australian financial stress. Although, both models show some promise, each model fell short of giving adequate forecasts in financial stress especially at the peak time of the 2007-2009 GFC. Thus, more research is needed to understand the complex nature of financial crisis, how crises develop and the techniques that can be used to predict the onset of financial crises.
- Description: Doctor of Philosophy
A kinship of creatures : Exploring the mutuality of lived experience
- Authors: Ní Shíocháin, Máirín
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text: false
- Description: This practice-led research explores questions of interspecies empathy, mutuality and kinship within the context of visual art. The study is situated broadly within the cross-disciplinary field of Animal Studies and espouses an animal advocacy stance within contemporary arts practice. It addresses concerns about the role of animals in contemporary art and proposes that creating art should not subordinate the ethical treatment of animals. The parameters of this investigation are defined by empathy theory, or Einfühlung. This was deemed an appropriate foundation to underpin the research given its historical association with aesthetic perceptions of works of art as well as empathic responses to other living entities including non-humans. Einfühlung and other contributing conceptual frameworks, including compassionate conservation and animal individuality are thoroughly evaluated in a review of relevant literature. Current arts practice in which the ‘animal’ plays a role is critically examined. The consequences for animals in contemporary art are more often malign than benign and this contrasts with progressive thinking about animal sentience in other areas of philosophical research. In a distillation of the above theoretical concepts, the research further references issues relating to selective application of care for non-human animals, in which the level of consideration is often dependent on human perceptions of the creatures’ status, for example native or introduced animals. The results of the research were revealed through a body of practical work including sculpture, collage, prints and artists’ books which depict a variety of animals and birds, both native and non-native, encountered as part of everyday experience; a visual exploration in which human-perspective classification of animals does not play a part.
- Description: Doctor of Philosophy
Accurate and efficient clustering algorithms for very large data sets
- Authors: Quddus, Syed
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: The ability to mine and extract useful information from large data sets is a common concern for organizations. Data over the internet is rapidly increasing and the importance of development of new approaches to collect, store and mine large amounts of data is significantly increasing. Clustering is one of the main tasks in data mining. Many clustering algorithms have been proposed but there are still clustering problems that have not been addressed in depth especially the clustering problems in large data sets. Clustering in large data sets is important in many applications and such applications include network intrusion detection systems, fraud detection in banking systems, air traffic control, web logs, sensor networks, social networks and bioinformatics. Data sets in these applications contain from hundreds of thousands to hundreds of millions of data points and they may contain hundreds or thousands of attributes. Recent developments in computer hardware allows to store in random access memory and repeatedly read data sets with hundreds of thousands and even millions of data points. This makes possible the use of existing clustering algorithms in such data sets. However, these algorithms require a prohibitively large CPU time and fail to produce an accurate solution. Therefore, it is important to develop clustering algorithms which are accurate and can provide real time clustering in such data sets. This is especially important in a big data era. The aim of this PhD study is to develop accurate and real time algorithms for clustering in very large data sets containing hundreds of thousands and millions of data points. Such algorithms are developed based on the combination of heuristic algorithms with the incremental approach. These algorithms also involve a special procedure to identify dense areas in a data set and compute a subset most informative representative data points in order to decrease the size of a data set. It is the aim of this PhD study to develop the center-based clustering algorithms. The success of these algorithms strongly depends on the choice of starting cluster centers. Different procedures are proposed to generate such centers. Special procedures are designed to identify the most promising starting cluster centers and to restrict their number. New clustering algorithms are evaluated using large data sets available in public domains. Their results will be compared with those obtained using several existing center-based clustering algorithms.
- Description: Doctor of Philosophy
- Authors: Quddus, Syed
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: The ability to mine and extract useful information from large data sets is a common concern for organizations. Data over the internet is rapidly increasing and the importance of development of new approaches to collect, store and mine large amounts of data is significantly increasing. Clustering is one of the main tasks in data mining. Many clustering algorithms have been proposed but there are still clustering problems that have not been addressed in depth especially the clustering problems in large data sets. Clustering in large data sets is important in many applications and such applications include network intrusion detection systems, fraud detection in banking systems, air traffic control, web logs, sensor networks, social networks and bioinformatics. Data sets in these applications contain from hundreds of thousands to hundreds of millions of data points and they may contain hundreds or thousands of attributes. Recent developments in computer hardware allows to store in random access memory and repeatedly read data sets with hundreds of thousands and even millions of data points. This makes possible the use of existing clustering algorithms in such data sets. However, these algorithms require a prohibitively large CPU time and fail to produce an accurate solution. Therefore, it is important to develop clustering algorithms which are accurate and can provide real time clustering in such data sets. This is especially important in a big data era. The aim of this PhD study is to develop accurate and real time algorithms for clustering in very large data sets containing hundreds of thousands and millions of data points. Such algorithms are developed based on the combination of heuristic algorithms with the incremental approach. These algorithms also involve a special procedure to identify dense areas in a data set and compute a subset most informative representative data points in order to decrease the size of a data set. It is the aim of this PhD study to develop the center-based clustering algorithms. The success of these algorithms strongly depends on the choice of starting cluster centers. Different procedures are proposed to generate such centers. Special procedures are designed to identify the most promising starting cluster centers and to restrict their number. New clustering algorithms are evaluated using large data sets available in public domains. Their results will be compared with those obtained using several existing center-based clustering algorithms.
- Description: Doctor of Philosophy
Algae-based models to configure consumptive flows for ecological benefit in the highly regulated MacKenzie River, south-east Australia
- Authors: Atazadeh, Ehsan
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Many river ecosystems, especially those in arid and semi-arid, are experiencing severe stress due to the increasing demands on the ecosystem services they provide, coupled with anthropogenic catchment impacts and factors associated with climate change and weather extremes. The flow regime of the Mackenzie River was substantially modified since the construction of a water supply reservoir on its upper reach in 1887. Water is now regulated at several locations downstream of the reservoir, creating a substantially modified flow regime, impacting key environmental values of the river. The river receives an environmental flow allocation and the river channel is used to transfer water dedicated for consumptive use. Water Quality and algal monitoring formed the basis of models that were developed evaluate the ecological condition of this working river under base flow and before, during and after freshes that deliver water to users. Samples of diatoms, soft algae and measurements of water quality were analysed at ten sampling sites for three years (between February 2012 and November 2014) along the MacKenzie River in different seasons and under different flow regimes to understand the spatial and temporal variation in the relationship between algal communities and water quality, and so stream condition. Baseline information on algal communities and water quality was collected during base flow conditions, while experiments on the effect of water releases on algal communities were based on flow regime variations (manipulated flow regimes), specifically on the algae community structure, water quality and ecosystem function. These comprised cease to flow (0 ML/day), low flows (10-15 ML/day), freshes (35-40 ML/day) and high flow (55ML/day) conditions. Physical and chemical characteristics of water, including pH, temperature, turbidity, electrical conductivity, dissolved oxygen, total nitrogen, phosphorus and cations and anions were measured. Biological properties of the algal periphyton communities, including dry mass, ash-free dry mass, chlorophyll-a concentration and species composition, were also measured. Furthermore, the DSIAR (Diatom Species Index for Australian Rivers) score was calculated to classify the condition of the waterway. The results showed the algal species composition changed under different flow regimes along the river. The sensitivity of diatoms to changes in water quality and flow rates deemed them useful indicators of river condition. The results indicated that flows tended to improve DSIAR scores and diatoms versus green algae and cyanobacteria biomass measures in the mid and lower reaches. The biological properties of the algal periphyton communities, and the species composition, varied between sites under different flow regimes. The accumulation of dry mass (not ash-free) decreased downstream during freshes, however the accumulation of AFDM (ash-free dry mass) gradually increased downstream. The results showed that the concentration of chlorophyll-a decreased downstream under water release events. The Pearson’s correlation matrix revealed flow regimes had a significant influence on the water chemistry characteristics and biological properties. The principal component analysis (PCA) illustrated that upstream species of algae were associated with low pH and temperature and higher DO. In contrast downstream species were associated with higher turbidity, TSS, conductivity, TN, and TDS. The correspondence analysis (CA) and detrended correspondence analysis (DCA) showed a split between algal assemblages during water release events in comparison with before and after water release. The canonical correspondence analysis (CCA) identified five significant environmental variables including pH, TSS, Turbidity, TN and TP explaining algal assemblage and structure along the river. The collected data were used to develop ecological response models based on algae communities living under different flow regimes in the MacKenzie River. The algae-based models across a hydraulic gradient may be useful in water management efforts to find sustainable solutions in the river by balancing environmental and human values. The empirical data and models showed the lower reaches of the river to be in poor condition under low flows, but this condition improved under flows of 35 ML/day, as indicated by the reduction in green algae and cyanobacteria and improvement in DSIAR scores. The results are presented to tailor discharge and duration of the river flows by amalgamation of consumptive and environmental flows to improve the condition of the stream thereby supplementing the flows dedicated to environmental outcomes. Ultimately the findings can be used by management to configure consumptive flows to enhance the for ecological condition of the MacKenzie River.
- Description: Doctor of Philosophy
- Authors: Atazadeh, Ehsan
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Many river ecosystems, especially those in arid and semi-arid, are experiencing severe stress due to the increasing demands on the ecosystem services they provide, coupled with anthropogenic catchment impacts and factors associated with climate change and weather extremes. The flow regime of the Mackenzie River was substantially modified since the construction of a water supply reservoir on its upper reach in 1887. Water is now regulated at several locations downstream of the reservoir, creating a substantially modified flow regime, impacting key environmental values of the river. The river receives an environmental flow allocation and the river channel is used to transfer water dedicated for consumptive use. Water Quality and algal monitoring formed the basis of models that were developed evaluate the ecological condition of this working river under base flow and before, during and after freshes that deliver water to users. Samples of diatoms, soft algae and measurements of water quality were analysed at ten sampling sites for three years (between February 2012 and November 2014) along the MacKenzie River in different seasons and under different flow regimes to understand the spatial and temporal variation in the relationship between algal communities and water quality, and so stream condition. Baseline information on algal communities and water quality was collected during base flow conditions, while experiments on the effect of water releases on algal communities were based on flow regime variations (manipulated flow regimes), specifically on the algae community structure, water quality and ecosystem function. These comprised cease to flow (0 ML/day), low flows (10-15 ML/day), freshes (35-40 ML/day) and high flow (55ML/day) conditions. Physical and chemical characteristics of water, including pH, temperature, turbidity, electrical conductivity, dissolved oxygen, total nitrogen, phosphorus and cations and anions were measured. Biological properties of the algal periphyton communities, including dry mass, ash-free dry mass, chlorophyll-a concentration and species composition, were also measured. Furthermore, the DSIAR (Diatom Species Index for Australian Rivers) score was calculated to classify the condition of the waterway. The results showed the algal species composition changed under different flow regimes along the river. The sensitivity of diatoms to changes in water quality and flow rates deemed them useful indicators of river condition. The results indicated that flows tended to improve DSIAR scores and diatoms versus green algae and cyanobacteria biomass measures in the mid and lower reaches. The biological properties of the algal periphyton communities, and the species composition, varied between sites under different flow regimes. The accumulation of dry mass (not ash-free) decreased downstream during freshes, however the accumulation of AFDM (ash-free dry mass) gradually increased downstream. The results showed that the concentration of chlorophyll-a decreased downstream under water release events. The Pearson’s correlation matrix revealed flow regimes had a significant influence on the water chemistry characteristics and biological properties. The principal component analysis (PCA) illustrated that upstream species of algae were associated with low pH and temperature and higher DO. In contrast downstream species were associated with higher turbidity, TSS, conductivity, TN, and TDS. The correspondence analysis (CA) and detrended correspondence analysis (DCA) showed a split between algal assemblages during water release events in comparison with before and after water release. The canonical correspondence analysis (CCA) identified five significant environmental variables including pH, TSS, Turbidity, TN and TP explaining algal assemblage and structure along the river. The collected data were used to develop ecological response models based on algae communities living under different flow regimes in the MacKenzie River. The algae-based models across a hydraulic gradient may be useful in water management efforts to find sustainable solutions in the river by balancing environmental and human values. The empirical data and models showed the lower reaches of the river to be in poor condition under low flows, but this condition improved under flows of 35 ML/day, as indicated by the reduction in green algae and cyanobacteria and improvement in DSIAR scores. The results are presented to tailor discharge and duration of the river flows by amalgamation of consumptive and environmental flows to improve the condition of the stream thereby supplementing the flows dedicated to environmental outcomes. Ultimately the findings can be used by management to configure consumptive flows to enhance the for ecological condition of the MacKenzie River.
- Description: Doctor of Philosophy
Cardiovascular data analytics for real time patient monitoring
- Authors: Allami, Ragheed
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Improvements in wearable sensor devices make it possible to constantly monitor physiological parameters such as electrocardiograph (ECG) signals for long periods. Remote patient monitoring with wearable sensors has an important role to play in health care, particularly given the prevalence of chronic conditions such as cardiovascular disease (CVD)—one of the prominent causes of morbidity and mortality worldwide. Approximately 4.2 million Australians suffer from long-term CVD with approximately one death every 12 minutes. The assessment of ECG features, especially heart rate variability (HRV), represents a non-invasive technique which provides an indication of the autonomic nervous system (ANS) function. Conditions such as sudden cardiac death, hypertension, heart failure, myocardial infarction, ischaemia, and coronary heart disease can be detected from HRV analysis. In addition, the analysis of ECG features can also be used to diagnose many types of life-threatening arrhythmias, including ventricular fibrillation and ventricular tachycardia. Non-cardiac conditions, such as diabetes, obesity, metabolic syndrome, insulin resistance, irritable bowel syndrome, dyspepsia, anorexia nervosa, anxiety, and major depressive disorder have also been shown to be associated with HRV. The analysis of ECG features from real time ECG signals generated from wearable sensors provides distinctive challenges. The sensors that receive and process the signals have limited power, storage and processing capacity. Consequently, algorithms that process ECG signals need to be lightweight, use minimal storage resources and accurately detect abnormalities so that alarms can be raised. The existing literature details only a few algorithms which operate within the constraints of wearable sensor networks. This research presents four novel techniques that enable ECG signals to be processed within the limitations of resource constraints on devices to detect some key abnormalities in heart function. - The first technique is a novel real-time ECG data reduction algorithm, which detects and transmits only those key points that are critical for the generation of ECG features for diagnoses. - The second technique accurately predicts the five-minute HRV measure using only three minutes of data with an algorithm that executes in real-time using minimal computational resources. - The third technique introduces a real-time ECG feature recognition system that can be applied to diagnose life threatening conditions such as premature ventricular contractions (PVCs). - The fourth technique advances a classification algorithm to enhance the performance of automated ECG classification to determine arrhythmic heart beats based on noisy ECG signals. The four novel techniques are evaluated in comparison with benchmark algorithms for each task on the standard MIT-BIH Arrhythmia Database and with data generated from patients in a major hospital using Shimmer3 wearable ECG sensors. The four techniques are integrated to demonstrate that remote patient monitoring of ECG using HRV and ECG features is feasible in real time using minimal computational resources. The evaluation show that the ECG reduction algorithm is significantly better than existing algorithms that can be applied within sensor nodes, such as time-domain methods, transformation methods and compressed sensing methods. Furthermore, the proposed ECG reduction is found to be computationally less complex for resource constrained sensors and achieves higher compression ratios than existing algorithms. The prediction of a common HRV measure, the five-minute standard deviation of inter-beat variations (SDNN) and the accurate detection of PVC beats was achieved using a Count Data Model, combined with a Poisson-generated function from three-minute ECG recordings. This was achieved with minimal computational resources and was well suited to remote patient monitoring with wearable sensors. The PVC beats detection was implemented using the same count data model together with knowledge-based rules derived from clinical knowledge. A real-time cardiac patient monitoring system was implemented using an ECG sensor and smartphone to detect PVC beats within a few seconds using artificial neural networks (ANN), and it was proven to provide highly accurate results. The automated detection and classification were implemented using a new wrapper-based hybrid approach that utilized t-distributed stochastic neighbour embedding (t-SNE) in combination with self-organizing maps (SOM) to improve classification performance. The t-SNE-SOM hybrid resulted in improved sensitivity, specificity and accuracy compared to most common hybrid methods in the presence of noise. It also provided a better, more accurate identification for the presence of many types of arrhythmias from the ECG recordings, leading to a more timely diagnosis and treatment outcome.
- Description: Doctor of Philosophy
- Authors: Allami, Ragheed
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Improvements in wearable sensor devices make it possible to constantly monitor physiological parameters such as electrocardiograph (ECG) signals for long periods. Remote patient monitoring with wearable sensors has an important role to play in health care, particularly given the prevalence of chronic conditions such as cardiovascular disease (CVD)—one of the prominent causes of morbidity and mortality worldwide. Approximately 4.2 million Australians suffer from long-term CVD with approximately one death every 12 minutes. The assessment of ECG features, especially heart rate variability (HRV), represents a non-invasive technique which provides an indication of the autonomic nervous system (ANS) function. Conditions such as sudden cardiac death, hypertension, heart failure, myocardial infarction, ischaemia, and coronary heart disease can be detected from HRV analysis. In addition, the analysis of ECG features can also be used to diagnose many types of life-threatening arrhythmias, including ventricular fibrillation and ventricular tachycardia. Non-cardiac conditions, such as diabetes, obesity, metabolic syndrome, insulin resistance, irritable bowel syndrome, dyspepsia, anorexia nervosa, anxiety, and major depressive disorder have also been shown to be associated with HRV. The analysis of ECG features from real time ECG signals generated from wearable sensors provides distinctive challenges. The sensors that receive and process the signals have limited power, storage and processing capacity. Consequently, algorithms that process ECG signals need to be lightweight, use minimal storage resources and accurately detect abnormalities so that alarms can be raised. The existing literature details only a few algorithms which operate within the constraints of wearable sensor networks. This research presents four novel techniques that enable ECG signals to be processed within the limitations of resource constraints on devices to detect some key abnormalities in heart function. - The first technique is a novel real-time ECG data reduction algorithm, which detects and transmits only those key points that are critical for the generation of ECG features for diagnoses. - The second technique accurately predicts the five-minute HRV measure using only three minutes of data with an algorithm that executes in real-time using minimal computational resources. - The third technique introduces a real-time ECG feature recognition system that can be applied to diagnose life threatening conditions such as premature ventricular contractions (PVCs). - The fourth technique advances a classification algorithm to enhance the performance of automated ECG classification to determine arrhythmic heart beats based on noisy ECG signals. The four novel techniques are evaluated in comparison with benchmark algorithms for each task on the standard MIT-BIH Arrhythmia Database and with data generated from patients in a major hospital using Shimmer3 wearable ECG sensors. The four techniques are integrated to demonstrate that remote patient monitoring of ECG using HRV and ECG features is feasible in real time using minimal computational resources. The evaluation show that the ECG reduction algorithm is significantly better than existing algorithms that can be applied within sensor nodes, such as time-domain methods, transformation methods and compressed sensing methods. Furthermore, the proposed ECG reduction is found to be computationally less complex for resource constrained sensors and achieves higher compression ratios than existing algorithms. The prediction of a common HRV measure, the five-minute standard deviation of inter-beat variations (SDNN) and the accurate detection of PVC beats was achieved using a Count Data Model, combined with a Poisson-generated function from three-minute ECG recordings. This was achieved with minimal computational resources and was well suited to remote patient monitoring with wearable sensors. The PVC beats detection was implemented using the same count data model together with knowledge-based rules derived from clinical knowledge. A real-time cardiac patient monitoring system was implemented using an ECG sensor and smartphone to detect PVC beats within a few seconds using artificial neural networks (ANN), and it was proven to provide highly accurate results. The automated detection and classification were implemented using a new wrapper-based hybrid approach that utilized t-distributed stochastic neighbour embedding (t-SNE) in combination with self-organizing maps (SOM) to improve classification performance. The t-SNE-SOM hybrid resulted in improved sensitivity, specificity and accuracy compared to most common hybrid methods in the presence of noise. It also provided a better, more accurate identification for the presence of many types of arrhythmias from the ECG recordings, leading to a more timely diagnosis and treatment outcome.
- Description: Doctor of Philosophy
Contemporary applications of Fresco : The narrative of the artist
- Authors: Chappell, Annette
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Fresco is a vehicle for powerful and enduring forms of cultural storytelling; it references universal narrative themes. The research objective of this project is to achieve a contemporary application of fresco through exploration and transgression of traditional material, pictorial forms and functions. In this transgression, the artist locates a personal narrative, through the immersive methods of autoethnographic inquiry and from the epistemological position of material thinking and production. The contemporary application of fresco is arrived at by interrogating the traditional methods, materials and intentions of fresco as recorded in fifteenth-century Europe and with reference to what other contemporary practitioners in this field have achieved. Materials knowledge and methods gained through on-site material conservation of lime plaster fresco is an impetus to this project and has engendered a focus on re-purposing and re-imagining the media in contemporary and personal expressions. The narrative of the artist is arrived at through materials thinking in fresco methodology, and through an interpretive autoethnographic analysis of a personal archive or studio text consisting of visual and textual material. The studio text is regarded as a unique ethnographic artefact of personal significance. The new term of ‘studio text’ for practice-led research is proposed to differentiate practice-led language and forms from the sociological or positivist terminology of ‘fieldwork notes’ or ‘data’. Autoethnographic methodology is disrupted to incorporate the indwelling practices of material thinking and immersive writing (ekphrasis) and drawing (enstasis). Through the integration of these methodologies, interpretations of the studio text are enacted concurrently with material production. Materials and motifs are selected for personal significance and resonance, and constructed as part or full frescoes. The material outcomes of this integration of methodologies are described as Visual Diaries and publicly exhibited. The documentation of integrated methodology in this project may contribute to emergent thinking in practice-led research.
- Description: Doctor of Philosophy
- Authors: Chappell, Annette
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Fresco is a vehicle for powerful and enduring forms of cultural storytelling; it references universal narrative themes. The research objective of this project is to achieve a contemporary application of fresco through exploration and transgression of traditional material, pictorial forms and functions. In this transgression, the artist locates a personal narrative, through the immersive methods of autoethnographic inquiry and from the epistemological position of material thinking and production. The contemporary application of fresco is arrived at by interrogating the traditional methods, materials and intentions of fresco as recorded in fifteenth-century Europe and with reference to what other contemporary practitioners in this field have achieved. Materials knowledge and methods gained through on-site material conservation of lime plaster fresco is an impetus to this project and has engendered a focus on re-purposing and re-imagining the media in contemporary and personal expressions. The narrative of the artist is arrived at through materials thinking in fresco methodology, and through an interpretive autoethnographic analysis of a personal archive or studio text consisting of visual and textual material. The studio text is regarded as a unique ethnographic artefact of personal significance. The new term of ‘studio text’ for practice-led research is proposed to differentiate practice-led language and forms from the sociological or positivist terminology of ‘fieldwork notes’ or ‘data’. Autoethnographic methodology is disrupted to incorporate the indwelling practices of material thinking and immersive writing (ekphrasis) and drawing (enstasis). Through the integration of these methodologies, interpretations of the studio text are enacted concurrently with material production. Materials and motifs are selected for personal significance and resonance, and constructed as part or full frescoes. The material outcomes of this integration of methodologies are described as Visual Diaries and publicly exhibited. The documentation of integrated methodology in this project may contribute to emergent thinking in practice-led research.
- Description: Doctor of Philosophy
Create, curate, cooperate : Exploring the process of sport safety resource development
- Authors: Bekker, Sheree
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Sports injuries are a significant public health burden both in Australia, and worldwide. Preventing injuries in sports settings is thus an important public health goal. It is now generally accepted that sports injuries are, like other unintentional injuries, largely preventable. Yet intractable problems remain. Complexity theory is harnessed in this research as a means of understanding such problems. To provide new insights into the complexity of sports safety promotion, this research consisted of a qualitative case study design underpinned by constructivist assumptions. Study A documented sports injury prevention and safety promotion resources available from the websites of key sporting organisations. A thematic document analysis approach was used to identify and describe how many, and what types of, resources were available, as well as the sports injury prevention and safety promotion issues addressed. The findings of Study A suggest that sport settings have access to a proliferation of rival resources, which reflects a potentially inefficient and ineffective manner in which to influence policy/practice. Study B determined the process that key intermediary organisations used to develop and disseminate the resources identified in Study A. Interviews with key participants about organisational processes of knowledge translation were undertaken, and a qualitative description approach was used to examine their accounts. The findings of Study B suggest that intermediary organisations can, and do, take on knowledge translation roles in order to make research knowledge more relevant (timely, salient, actionable), accessible (formatted and available), and legitimate (credible) for end-users. A complexity approach was applied to this study to assist in recognising that open systems (stratification and fluidity), non-linearity (emergent properties and feedback loops), and improbability (demi-regularities and the ability to evolve, learn, and adapt) underscore sports safety. This study explicates and examines key insights and implications of adopting a complexity approach to the prevention of injury in sport settings.
- Description: Doctor of Philosophy
- Authors: Bekker, Sheree
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Sports injuries are a significant public health burden both in Australia, and worldwide. Preventing injuries in sports settings is thus an important public health goal. It is now generally accepted that sports injuries are, like other unintentional injuries, largely preventable. Yet intractable problems remain. Complexity theory is harnessed in this research as a means of understanding such problems. To provide new insights into the complexity of sports safety promotion, this research consisted of a qualitative case study design underpinned by constructivist assumptions. Study A documented sports injury prevention and safety promotion resources available from the websites of key sporting organisations. A thematic document analysis approach was used to identify and describe how many, and what types of, resources were available, as well as the sports injury prevention and safety promotion issues addressed. The findings of Study A suggest that sport settings have access to a proliferation of rival resources, which reflects a potentially inefficient and ineffective manner in which to influence policy/practice. Study B determined the process that key intermediary organisations used to develop and disseminate the resources identified in Study A. Interviews with key participants about organisational processes of knowledge translation were undertaken, and a qualitative description approach was used to examine their accounts. The findings of Study B suggest that intermediary organisations can, and do, take on knowledge translation roles in order to make research knowledge more relevant (timely, salient, actionable), accessible (formatted and available), and legitimate (credible) for end-users. A complexity approach was applied to this study to assist in recognising that open systems (stratification and fluidity), non-linearity (emergent properties and feedback loops), and improbability (demi-regularities and the ability to evolve, learn, and adapt) underscore sports safety. This study explicates and examines key insights and implications of adopting a complexity approach to the prevention of injury in sport settings.
- Description: Doctor of Philosophy
Design and modelling of the limaçon positive displacement gas expander
- Authors: Phung, Truong
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: The limaçon positive displacement technology has been featured in a number of patents over the last 100 years. The technology offers a two-lobe rotor that slides and rotates in a rounded cavity so as to create a pair of variable-volume chambers suited for fluid processing. As such, it can be employed to manufacture gas expanders to extract work from low-grade heat or other heat resources. Positive displacement gas expanders are applied to small-scale power generation plants which can be used for a number of applications such as to improve the energy efficiency of existing thermal processes. This thesis features work undertaken to develop models to inform and enhance the design process such that an optimised limaçon machine is produced. The models developed in the thesis efficiently predict and characterise the performance of the limaçon gas expander irrespective of the working fluid used or the phase transformation that takes place during the working of the expander. The models developed are multiphysics in nature as they incorporate the vibration analysis of the apex seals with the thermodynamical differential description of the working medium together with the dynamical characterisation of an electro-mechanical control valve fitted to regulate the amount of fluid allowed into the working chamber. Chapter 1 starts with a problem statement that addresses the questions which the author aims to answer upon the completion of this project. The chapter offers a detailed background on the limaçon technology and where it falls in relation to other fluid processing machines. Chapter 1 is also a literature review which spans such aspects as:
- Description: Doctor of Philosophy
- Authors: Phung, Truong
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: The limaçon positive displacement technology has been featured in a number of patents over the last 100 years. The technology offers a two-lobe rotor that slides and rotates in a rounded cavity so as to create a pair of variable-volume chambers suited for fluid processing. As such, it can be employed to manufacture gas expanders to extract work from low-grade heat or other heat resources. Positive displacement gas expanders are applied to small-scale power generation plants which can be used for a number of applications such as to improve the energy efficiency of existing thermal processes. This thesis features work undertaken to develop models to inform and enhance the design process such that an optimised limaçon machine is produced. The models developed in the thesis efficiently predict and characterise the performance of the limaçon gas expander irrespective of the working fluid used or the phase transformation that takes place during the working of the expander. The models developed are multiphysics in nature as they incorporate the vibration analysis of the apex seals with the thermodynamical differential description of the working medium together with the dynamical characterisation of an electro-mechanical control valve fitted to regulate the amount of fluid allowed into the working chamber. Chapter 1 starts with a problem statement that addresses the questions which the author aims to answer upon the completion of this project. The chapter offers a detailed background on the limaçon technology and where it falls in relation to other fluid processing machines. Chapter 1 is also a literature review which spans such aspects as:
- Description: Doctor of Philosophy
Dr James Stewart : Irish doctor and philanthropist on the Ballarat goldfields
- Authors: Cousen, Nicola
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis is the first in-depth biography of Dr James Stewart (1829-1906), an Ulster Presbyterian doctor who spent his prime years in Victoria between 1852 and 1869. It answers the question of who James Stewart was and why such an important actor in the history of Ballarat and colonial Victoria has been almost completely ignored by the historical record. The thesis explores the themes of identity and class by revealing the elements that shaped who Stewart was as well as his contributions to Ballarat and the colony through his medical work, civic duty, philanthropy and capitalist investment. Beginning with his early life in rural Ulster and medical education in Dublin, insight is provided into his emigration as a ship’s surgeon to the Ballarat goldfields in the context of the Irish diaspora. New light is thrown on the formative experience of ships’ surgeons and their role in the development of colonial medicine and civic duty; medical care available on the goldfields and during the events of the Eureka Stockade; and the professionalisation of medicine in colonial Victoria. In pursuing the biographical method advocated by Robert Rotberg, in the absence of personal records, it makes extensive use of newspapers and the archives of the institutions to which he contributed significantly. Interpretative and speculative methods are employed to carefully analyse his detailed will and obituaries. This study finds that Stewart’s flexible identity facilitated his involvement with a variety of community, class and social groups. Examination of his religious influences provides new understanding of Ulster Presbyterians and the Anglo-Irish in Victoria and challenges Patrick O’Farrell’s claim that the Anglo-Irish in Australia were right-wing conservatives. A major contributor to the development of Ballarat, a visionary and generous benefactor, James Stewart’s legacy continues to have an impact more than a century after his death.
- Description: Doctor of Philosophy
- Authors: Cousen, Nicola
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis is the first in-depth biography of Dr James Stewart (1829-1906), an Ulster Presbyterian doctor who spent his prime years in Victoria between 1852 and 1869. It answers the question of who James Stewart was and why such an important actor in the history of Ballarat and colonial Victoria has been almost completely ignored by the historical record. The thesis explores the themes of identity and class by revealing the elements that shaped who Stewart was as well as his contributions to Ballarat and the colony through his medical work, civic duty, philanthropy and capitalist investment. Beginning with his early life in rural Ulster and medical education in Dublin, insight is provided into his emigration as a ship’s surgeon to the Ballarat goldfields in the context of the Irish diaspora. New light is thrown on the formative experience of ships’ surgeons and their role in the development of colonial medicine and civic duty; medical care available on the goldfields and during the events of the Eureka Stockade; and the professionalisation of medicine in colonial Victoria. In pursuing the biographical method advocated by Robert Rotberg, in the absence of personal records, it makes extensive use of newspapers and the archives of the institutions to which he contributed significantly. Interpretative and speculative methods are employed to carefully analyse his detailed will and obituaries. This study finds that Stewart’s flexible identity facilitated his involvement with a variety of community, class and social groups. Examination of his religious influences provides new understanding of Ulster Presbyterians and the Anglo-Irish in Victoria and challenges Patrick O’Farrell’s claim that the Anglo-Irish in Australia were right-wing conservatives. A major contributor to the development of Ballarat, a visionary and generous benefactor, James Stewart’s legacy continues to have an impact more than a century after his death.
- Description: Doctor of Philosophy