Optimising water quality outcomes for complex water resource systems and water grids
- Authors: Dey, Sayani
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: As the world progresses, water resources are likely to be subjected to much greater pressures than in the past. Even though the principal water problem revolves around inadequate and uncertain water supplies, water quality management plays an equally important role. Availability of good quality water is paramount to sustainability of human population as well as the environment. Achieving water quality and quantity objectives can be conflicting and becomes more complicated with challenges like, climate change, growing populations and changed land uses. Managing adequate water quality in a reservoir gets complicated by multiple inflows with different water quality levels often resulting in poor water quality. Hence, it is fundamental to approach this issue in a more systematic, comprehensive, and coordinated fashion. Most previous studies related to water resources management focused on water quantity and considered water quality separately. However, this research study focused on considering water quantity and quality objectives simultaneously in a single model to explore and understand the relationship between them in a reservoir system. A case study area was identified in Western Victoria, Australia with water quantity and quality challenges. Taylors Lake of Grampians System in Victoria, Australia receives water from multiple sources of differing quality and quantity and has the abovesaid problems. A combined simulation and optimisation approach was adopted to carry out the analysis. A multi-objective optimisation approach was applied to achieve optimal water availability and quality in the storage. The multi-objective optimisation model included three objective functions which were: water volume and two water quality parameters: salinity and turbidity. Results showed competing nature of water quantity and quality objectives and established the trade-offs. It further showed that it was possible to generate a range of optimal solutions to effectively manage those trade-offs. The trade-off analysis explored and informed that selective harvesting of inflows is effective to improve water quality in storage. However, with strict water quality restriction there is a considerable loss in water volume. The robustness of the optimisation approach used in this study was confirmed through sensitivity and uncertainty analysis. The research work also incorporated various spatio-temporal scenario analyses to systematically articulate long-term and short-term operational planning strategies. Operational decisions around possible harvesting regimes while achieving optimal water quantity and quality and meeting all water demands were established. The climate change analysis revealed that optimal management of water quantity and quality in storage became extremely challenging under future climate projections. The high reduction in storage volume in the future will lead to several challenges such as water supply shortfall and inability to undertake selective harvesting due to reduced water quality levels. In this context, selective harvesting of inflows based on water quality will no longer be an option to manage water quantity and quality optimally in storage. Some significant conclusions of this research work included the establishment of trade-offs between water quality and quantity objectives particular to this configuration of water supply system. The work demonstrated that selective harvesting of inflows will improve the stored water quality, and this finding along with the approach used is a significant contribution to decision makers working within the water sector. The simulation-optimisation approach is very effective in providing a range of optimal solutions, which can be used to make more informed decisions around achieving optimal water quality and quantity in storage. It was further demonstrated that there are range of planning periods, both long-term (>10 years) and short-term (<1 year), all of which offer distinct advantages and provides useful insights, making this an additional key contribution of the work. Importantly, climate change was also considered where it was found that diminishing water resources, particularly to this geographic location, makes it increasingly difficult to optimise both quality and quantity in storage providing further useful insights from this work.
- Description: Doctor of Philosophy
- Authors: Dey, Sayani
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: As the world progresses, water resources are likely to be subjected to much greater pressures than in the past. Even though the principal water problem revolves around inadequate and uncertain water supplies, water quality management plays an equally important role. Availability of good quality water is paramount to sustainability of human population as well as the environment. Achieving water quality and quantity objectives can be conflicting and becomes more complicated with challenges like, climate change, growing populations and changed land uses. Managing adequate water quality in a reservoir gets complicated by multiple inflows with different water quality levels often resulting in poor water quality. Hence, it is fundamental to approach this issue in a more systematic, comprehensive, and coordinated fashion. Most previous studies related to water resources management focused on water quantity and considered water quality separately. However, this research study focused on considering water quantity and quality objectives simultaneously in a single model to explore and understand the relationship between them in a reservoir system. A case study area was identified in Western Victoria, Australia with water quantity and quality challenges. Taylors Lake of Grampians System in Victoria, Australia receives water from multiple sources of differing quality and quantity and has the abovesaid problems. A combined simulation and optimisation approach was adopted to carry out the analysis. A multi-objective optimisation approach was applied to achieve optimal water availability and quality in the storage. The multi-objective optimisation model included three objective functions which were: water volume and two water quality parameters: salinity and turbidity. Results showed competing nature of water quantity and quality objectives and established the trade-offs. It further showed that it was possible to generate a range of optimal solutions to effectively manage those trade-offs. The trade-off analysis explored and informed that selective harvesting of inflows is effective to improve water quality in storage. However, with strict water quality restriction there is a considerable loss in water volume. The robustness of the optimisation approach used in this study was confirmed through sensitivity and uncertainty analysis. The research work also incorporated various spatio-temporal scenario analyses to systematically articulate long-term and short-term operational planning strategies. Operational decisions around possible harvesting regimes while achieving optimal water quantity and quality and meeting all water demands were established. The climate change analysis revealed that optimal management of water quantity and quality in storage became extremely challenging under future climate projections. The high reduction in storage volume in the future will lead to several challenges such as water supply shortfall and inability to undertake selective harvesting due to reduced water quality levels. In this context, selective harvesting of inflows based on water quality will no longer be an option to manage water quantity and quality optimally in storage. Some significant conclusions of this research work included the establishment of trade-offs between water quality and quantity objectives particular to this configuration of water supply system. The work demonstrated that selective harvesting of inflows will improve the stored water quality, and this finding along with the approach used is a significant contribution to decision makers working within the water sector. The simulation-optimisation approach is very effective in providing a range of optimal solutions, which can be used to make more informed decisions around achieving optimal water quality and quantity in storage. It was further demonstrated that there are range of planning periods, both long-term (>10 years) and short-term (<1 year), all of which offer distinct advantages and provides useful insights, making this an additional key contribution of the work. Importantly, climate change was also considered where it was found that diminishing water resources, particularly to this geographic location, makes it increasingly difficult to optimise both quality and quantity in storage providing further useful insights from this work.
- Description: Doctor of Philosophy
Physical and emotional touchpoints influencing user journeys : how mothers navigate through the maternity and early childhood development service systems in a rural Victorian city
- Authors: O'Neill, Carina
- Date: 2023
- Type: Text , Thesis , Masters
- Full Text:
- Description: The quality of maternity and early childhood development service systems has a profound impact on children’s capacity to grow, learn and thrive throughout their lifespans. This research study investigated the experiences of first-time mothers attempting to navigate complex, disjointed service systems in a small rural Australian city. The study aimed to identify the critical touchpoints that first-time mothers often encountered when navigating maternity and early childhood development service systems from conception to school and then generate a broader understanding of how the individual and collective user might navigate through this period. In my capacity as the manager of a major early childhood service in this small city, I was able to apply my critical, reflexive insights of the service to the development of this research study. This descriptive, retrospective study employed a qualitative methodology. A novel, user-centred design approach – drawing upon the concept of service touchpoints – was applied to explain families’ experiences of using services from the point of their child’s conception until the commencement of school. A self-selected sample of eight first-time mothers participated in the study. Comprehensive, tape-recorded interviews were conducted with the mothers that incorporated innovative tools for generating ideas and identifying critical touchpoints during the mothers’ user journey. The data was analysed to produce four products: a cross-case, thematic analysis of the families’ experiences; a visual user journey map containing the physical and emotional service touchpoints for each individual family; and two customer journey maps (one showing physical touchpoints; the other showing emotional touchpoints) to visually represent the typical user’s experience. The four major themes that emerged were: (1) dissonance between expectations and the lived reality; (2) the continuum of support from ideal to going “above and beyond”; (3) social isolation and lack of information; and (4) the need to become experts/advocates to make informed choices. The two conjoint customer journey maps revealed that a lack of service knowledge, unclear processes and disruptions in service transitions impacted on the physical service experience. However, surprisingly, it was the emotional – rather than the physical –touchpoints that were most significant for these mothers.
- Description: Masters of the Arts
- Authors: O'Neill, Carina
- Date: 2023
- Type: Text , Thesis , Masters
- Full Text:
- Description: The quality of maternity and early childhood development service systems has a profound impact on children’s capacity to grow, learn and thrive throughout their lifespans. This research study investigated the experiences of first-time mothers attempting to navigate complex, disjointed service systems in a small rural Australian city. The study aimed to identify the critical touchpoints that first-time mothers often encountered when navigating maternity and early childhood development service systems from conception to school and then generate a broader understanding of how the individual and collective user might navigate through this period. In my capacity as the manager of a major early childhood service in this small city, I was able to apply my critical, reflexive insights of the service to the development of this research study. This descriptive, retrospective study employed a qualitative methodology. A novel, user-centred design approach – drawing upon the concept of service touchpoints – was applied to explain families’ experiences of using services from the point of their child’s conception until the commencement of school. A self-selected sample of eight first-time mothers participated in the study. Comprehensive, tape-recorded interviews were conducted with the mothers that incorporated innovative tools for generating ideas and identifying critical touchpoints during the mothers’ user journey. The data was analysed to produce four products: a cross-case, thematic analysis of the families’ experiences; a visual user journey map containing the physical and emotional service touchpoints for each individual family; and two customer journey maps (one showing physical touchpoints; the other showing emotional touchpoints) to visually represent the typical user’s experience. The four major themes that emerged were: (1) dissonance between expectations and the lived reality; (2) the continuum of support from ideal to going “above and beyond”; (3) social isolation and lack of information; and (4) the need to become experts/advocates to make informed choices. The two conjoint customer journey maps revealed that a lack of service knowledge, unclear processes and disruptions in service transitions impacted on the physical service experience. However, surprisingly, it was the emotional – rather than the physical –touchpoints that were most significant for these mothers.
- Description: Masters of the Arts
Statistical assessment of Australian bushfire conditions : long-term changes and variability
- Authors: Biswas, Soubhik
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: In the wake of increasing bushfire impacts in recent decades across the Australian landscape, questions arise regarding the role played by weather conditions, climate variability and long-term climate change. This thesis seeks to quantify the following components that can influence fire risk: (1) the effects of weather and mean climate conditions, (2) large-scale drivers of natural climate variability, (3) the influence of extreme weather events and (4) the contribution of long-term anthropogenic climate change. Bushfire risks associated with weather and climate factors in Australia are generally assessed using indices such as the Forest Fire Danger Index (FFDI). The FFDI is used in this study, calculated from daily values of rainfall, relative humidity, temperature and wind speed, providing a generalised approach for combining those four weather factors known to influence fire behaviour. This study also aims to fill several knowledge gaps in the literature. For example, a comprehensive study of climatology, variability and trends in Australia's fire weather conditions was never attempted before using a high-resolution and a very long-term fire weather dataset. The fire weather conditions were analysed using a long-term FFDI dataset constructed from 20th Century reanalysis climatic data with bias correction applied because reconstructed weather datasets like 20th Century reanalysis products often show systemic biases. Various statistical bias correction approaches based on quantile-quantile matching were compared, and a spline-based method was selected due to its higher precision in correcting a distribution for the purposes of this study. The relationship of this calibrated FFDI dataset with the climate drivers of El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Southern Annular Mode (SAM) and Interdecadal Pacific Oscillation (IPO) was analysed. Results are mapped to show the regional and seasonal fluctuations in the severe fire weather across Australia during different combinations of ENSO, IOD, and SAM phases. During the austral spring and summer seasons, the highest frequency of severe fire weather conditions occurred for the combination of positive ENSO (i.e., El Nino), positive IOD and negative SAM. The calibrated FFDI dataset derived from bias-corrected Twentieth Century Reanalysis data was further used to study the long-term climate change trends in Australian fire weather conditions. A general positive trend in the number of extreme FFDI days was reported across Australia, except for New South Wales in Spring where a statistically non-significant negative trend was observed. Temperature and relative humidity were found to be the most critical climatic variables influencing fire weather trends across the country, noting that relative humidity is partly based on temperature. The applications of this work range from being useful for various stakeholders in framing new climate change adaptation policies to being used for seasonal outlooks and planning by fire management teams.
- Description: Doctor of Philosophy
- Authors: Biswas, Soubhik
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: In the wake of increasing bushfire impacts in recent decades across the Australian landscape, questions arise regarding the role played by weather conditions, climate variability and long-term climate change. This thesis seeks to quantify the following components that can influence fire risk: (1) the effects of weather and mean climate conditions, (2) large-scale drivers of natural climate variability, (3) the influence of extreme weather events and (4) the contribution of long-term anthropogenic climate change. Bushfire risks associated with weather and climate factors in Australia are generally assessed using indices such as the Forest Fire Danger Index (FFDI). The FFDI is used in this study, calculated from daily values of rainfall, relative humidity, temperature and wind speed, providing a generalised approach for combining those four weather factors known to influence fire behaviour. This study also aims to fill several knowledge gaps in the literature. For example, a comprehensive study of climatology, variability and trends in Australia's fire weather conditions was never attempted before using a high-resolution and a very long-term fire weather dataset. The fire weather conditions were analysed using a long-term FFDI dataset constructed from 20th Century reanalysis climatic data with bias correction applied because reconstructed weather datasets like 20th Century reanalysis products often show systemic biases. Various statistical bias correction approaches based on quantile-quantile matching were compared, and a spline-based method was selected due to its higher precision in correcting a distribution for the purposes of this study. The relationship of this calibrated FFDI dataset with the climate drivers of El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Southern Annular Mode (SAM) and Interdecadal Pacific Oscillation (IPO) was analysed. Results are mapped to show the regional and seasonal fluctuations in the severe fire weather across Australia during different combinations of ENSO, IOD, and SAM phases. During the austral spring and summer seasons, the highest frequency of severe fire weather conditions occurred for the combination of positive ENSO (i.e., El Nino), positive IOD and negative SAM. The calibrated FFDI dataset derived from bias-corrected Twentieth Century Reanalysis data was further used to study the long-term climate change trends in Australian fire weather conditions. A general positive trend in the number of extreme FFDI days was reported across Australia, except for New South Wales in Spring where a statistically non-significant negative trend was observed. Temperature and relative humidity were found to be the most critical climatic variables influencing fire weather trends across the country, noting that relative humidity is partly based on temperature. The applications of this work range from being useful for various stakeholders in framing new climate change adaptation policies to being used for seasonal outlooks and planning by fire management teams.
- Description: Doctor of Philosophy
Superannuation in Australia : a mixed methods study into engagement of superannuants
- Authors: Clinton, Teresa
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: Compulsory superannuation is a significant component of the Australian Government’s strategy to encourage citizens to take responsibility for funding their retirement. This project extends current knowledge regarding superannuants financial literacy and their preparedness to engage in the decision process that is embodied in the main communication document received from superannuation funds: the benefit statement. The purpose of this study involved two research questions. The first asked: What are the characteristics and determinants of a benefit statement as a form of financial communication to superannuants? The study aimed to determine if the benefit statement is fit for purpose and involved an examination of industry benefit statements. Institutional Theory was used to explain why benefit statements take their current form. The second research question considers to what extent superannuants understand and engage with the benefit statement? A survey of academics working at Australian public universities was undertaken to explore their financial literacy, understanding and extent of engagement they have with their superannuation via the benefit statement. The OECD/NIFE (2018, p. 4) definition of financial literacy was used for this research study as it incorporates “a combination of awareness, knowledge, skill, attitude and behaviour necessary to make sound financial decisions and ultimately achieve individual financial wellbeing”. The Theory of Planned Behaviour provides an explanation and a greater understanding of attitude and behaviour between demographics for example, age, gender, and education level that contribute to engagement with superannuation. A content analysis was used for research question 1, and found that due to legalisation requirements, a similar format has been adopted by most funds. There was however a lack of information which would allow superannuants the ability to track their preparedness for the amount required to fund retirement. With regard to the second research question, the results from the high socioeconomic group revealed that engagement with superannuation is not reflected by gender or education but rather age approaching retirement. As retirement approaches engagement increases. The attitude of participants towards superannuation was positive with most displaying high levels of self-efficacy however, a pre- and post-survey self-evaluation of financial literacy questions revealed a statistically significant decrease in scores indicating survey respondents were not actually aware of their lack of understanding of superannuation. The combined results from the survey and the content analysis indicate that the quality of disclosure is not sufficient to influence superannuants’ active engagement with their superannuation. This study highlights that engagement with superannuation is driven by personal circumstances and individual differences and the benefit statement needs to be more personally relevant to a broader range of individuals to encourage engagement with retirement planning. The findings help to understand heterogeneity in individuals’ propensity to engage with superannuation and provide an insight into their attitudes and behaviour. The research offers a contribution to the literature on superannuation fund benefit statement disclosure practices and provides an insight for policymakers on the effect these statements they have on superannuants.
- Description: Doctor of Philosophy
- Authors: Clinton, Teresa
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: Compulsory superannuation is a significant component of the Australian Government’s strategy to encourage citizens to take responsibility for funding their retirement. This project extends current knowledge regarding superannuants financial literacy and their preparedness to engage in the decision process that is embodied in the main communication document received from superannuation funds: the benefit statement. The purpose of this study involved two research questions. The first asked: What are the characteristics and determinants of a benefit statement as a form of financial communication to superannuants? The study aimed to determine if the benefit statement is fit for purpose and involved an examination of industry benefit statements. Institutional Theory was used to explain why benefit statements take their current form. The second research question considers to what extent superannuants understand and engage with the benefit statement? A survey of academics working at Australian public universities was undertaken to explore their financial literacy, understanding and extent of engagement they have with their superannuation via the benefit statement. The OECD/NIFE (2018, p. 4) definition of financial literacy was used for this research study as it incorporates “a combination of awareness, knowledge, skill, attitude and behaviour necessary to make sound financial decisions and ultimately achieve individual financial wellbeing”. The Theory of Planned Behaviour provides an explanation and a greater understanding of attitude and behaviour between demographics for example, age, gender, and education level that contribute to engagement with superannuation. A content analysis was used for research question 1, and found that due to legalisation requirements, a similar format has been adopted by most funds. There was however a lack of information which would allow superannuants the ability to track their preparedness for the amount required to fund retirement. With regard to the second research question, the results from the high socioeconomic group revealed that engagement with superannuation is not reflected by gender or education but rather age approaching retirement. As retirement approaches engagement increases. The attitude of participants towards superannuation was positive with most displaying high levels of self-efficacy however, a pre- and post-survey self-evaluation of financial literacy questions revealed a statistically significant decrease in scores indicating survey respondents were not actually aware of their lack of understanding of superannuation. The combined results from the survey and the content analysis indicate that the quality of disclosure is not sufficient to influence superannuants’ active engagement with their superannuation. This study highlights that engagement with superannuation is driven by personal circumstances and individual differences and the benefit statement needs to be more personally relevant to a broader range of individuals to encourage engagement with retirement planning. The findings help to understand heterogeneity in individuals’ propensity to engage with superannuation and provide an insight into their attitudes and behaviour. The research offers a contribution to the literature on superannuation fund benefit statement disclosure practices and provides an insight for policymakers on the effect these statements they have on superannuants.
- Description: Doctor of Philosophy
The Glovers : a settler family in Van Diemen’s land
- Authors: Hodson, Susan
- Date: 2023
- Type: Text , Thesis , Masters
- Full Text:
- Description: This thesis explores the experiences of the members of the Glover family, who migrated to Van Diemen’s Land in two parties. The first party consisted of the three sons of John Glover, the colonial painter (one accompanied by an English wife), who arrived in 1829; the second party, which included John Glover himself, arrived in 1831. This thesis explores the Glovers’ attempts to begin new lives as farmers after receiving free land grants from the colonial government, employing convict servants assigned to them. The Glover family members were witnesses to the late stages of the Black Wars. John Glover Senior’s arrival was after the Black Line offensive in 1830, but he sought out members of the Tasmanian Aboriginal community. He had contact with both proponents and antagonists of the Black Wars. Employing the methodology of documentary archival research, I investigated the historical background to the experiences of the Glovers, where I examined the issues of land grants, convict labour, the gender spike, and the Black Wars. This thesis includes an appraisal of the perseverance of the Glovers during the prolonged economic depression in the decade of the 1840s in Van Diemen’s Land, with John Glover Senior dying in 1849. Several changes introduced in 1840, including increased convict transportation to Van Diemen’s Land and a change in convict policy to the Probation system, led to hardship in the community. The history of the 1840s decade in Van Diemen’s Land has been relatively neglected. It had, however, been a decade of struggle until the economic recovery in the 1850s. John Glover’s artwork reflected his attitude towards his new home at Patterdale. He had been comfortable in this landscape and had developed a sense of belonging. His paintings, with their wide horizons and being flooded with sunlight, were unmistakably Australian. While his paintings had not been valued during his lifetime, they are now being appreciated for their skilful depiction of early colonial Australia.
- Description: Masters by Research
- Authors: Hodson, Susan
- Date: 2023
- Type: Text , Thesis , Masters
- Full Text:
- Description: This thesis explores the experiences of the members of the Glover family, who migrated to Van Diemen’s Land in two parties. The first party consisted of the three sons of John Glover, the colonial painter (one accompanied by an English wife), who arrived in 1829; the second party, which included John Glover himself, arrived in 1831. This thesis explores the Glovers’ attempts to begin new lives as farmers after receiving free land grants from the colonial government, employing convict servants assigned to them. The Glover family members were witnesses to the late stages of the Black Wars. John Glover Senior’s arrival was after the Black Line offensive in 1830, but he sought out members of the Tasmanian Aboriginal community. He had contact with both proponents and antagonists of the Black Wars. Employing the methodology of documentary archival research, I investigated the historical background to the experiences of the Glovers, where I examined the issues of land grants, convict labour, the gender spike, and the Black Wars. This thesis includes an appraisal of the perseverance of the Glovers during the prolonged economic depression in the decade of the 1840s in Van Diemen’s Land, with John Glover Senior dying in 1849. Several changes introduced in 1840, including increased convict transportation to Van Diemen’s Land and a change in convict policy to the Probation system, led to hardship in the community. The history of the 1840s decade in Van Diemen’s Land has been relatively neglected. It had, however, been a decade of struggle until the economic recovery in the 1850s. John Glover’s artwork reflected his attitude towards his new home at Patterdale. He had been comfortable in this landscape and had developed a sense of belonging. His paintings, with their wide horizons and being flooded with sunlight, were unmistakably Australian. While his paintings had not been valued during his lifetime, they are now being appreciated for their skilful depiction of early colonial Australia.
- Description: Masters by Research
Tropical cyclone prediction for the Solomon Islands region
- Authors: Haruhiru, Alick
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: Tropical cyclones (TCs) are among the costliest natural disasters impacting the Solomon Islands in the southwest Pacific due to its high vulnerability and low adaptive capacity to the hazard. Strong winds coupled with heavy rainfall often have devastating consequences on life and property. Occurrence of TCs in the Solomon Islands region – defined here as 5°–15°S and 155°–170°E – have large year-to-year variability over the period 1970-2019, ranging from TC numbers as low as zero to up to eight in some years. Geographically, the region spans the spatial phase change of the major climatic driver in the South Pacific, the El Niño Southern Oscillation (ENSO), and so the year-to-year variability of TCs here do not have any defined pattern. This creates a ‘predictability barrier’ for seasonal (and even sub-seasonal) prediction of TCs in the region. To circumvent the issue of TC predictability in the Solomon Islands region, I first objectively defined the total observed TCs into three specific clusters. Cluster-specific TCs showed improved patterns of variability with respect to natural modes of climate variability such as ENSO, the Madden Julian Oscillations (MJO) and Interdecadal Pacific Oscillations (IPO). I then developed sophisticated statistical prediction models for TCs in each cluster at seasonal and sub-seasonal timescales using ENSO, the MJO and IPO as main predictors. Overall, the results showed enhanced predictability skills of TCs up to several months in advance compared with methods that are currently being used by the Solomon Islands Meteorological Service. It is anticipated that improved seasonal and sub-seasonal predictions of TCs at various timescales can help disaster management agencies in the Solomon Islands with appropriate plannings and decision-making to lessen risks associated with TC events.
- Description: Doctor of Philosophy
- Authors: Haruhiru, Alick
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: Tropical cyclones (TCs) are among the costliest natural disasters impacting the Solomon Islands in the southwest Pacific due to its high vulnerability and low adaptive capacity to the hazard. Strong winds coupled with heavy rainfall often have devastating consequences on life and property. Occurrence of TCs in the Solomon Islands region – defined here as 5°–15°S and 155°–170°E – have large year-to-year variability over the period 1970-2019, ranging from TC numbers as low as zero to up to eight in some years. Geographically, the region spans the spatial phase change of the major climatic driver in the South Pacific, the El Niño Southern Oscillation (ENSO), and so the year-to-year variability of TCs here do not have any defined pattern. This creates a ‘predictability barrier’ for seasonal (and even sub-seasonal) prediction of TCs in the region. To circumvent the issue of TC predictability in the Solomon Islands region, I first objectively defined the total observed TCs into three specific clusters. Cluster-specific TCs showed improved patterns of variability with respect to natural modes of climate variability such as ENSO, the Madden Julian Oscillations (MJO) and Interdecadal Pacific Oscillations (IPO). I then developed sophisticated statistical prediction models for TCs in each cluster at seasonal and sub-seasonal timescales using ENSO, the MJO and IPO as main predictors. Overall, the results showed enhanced predictability skills of TCs up to several months in advance compared with methods that are currently being used by the Solomon Islands Meteorological Service. It is anticipated that improved seasonal and sub-seasonal predictions of TCs at various timescales can help disaster management agencies in the Solomon Islands with appropriate plannings and decision-making to lessen risks associated with TC events.
- Description: Doctor of Philosophy
Vulnerability modelling and mitigation strategies for hybrid networks
- Authors: Ur-Rehman, Attiq
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: Hybrid networks nowadays consist of traditional IT components, Internet of Things (IoT) and industrial control systems (ICS) nodes with varying characteristics, making them genuinely heterogeneous in nature. Historically evolving from traditional internet-enabled IT servers, hybrid networks allow organisations to strengthen cybersecurity, increase flexibility, improve efficiency, enhance reliability, boost remote connectivity and easy management. Though hybrid networks offer significant benefits from business and operational perspectives, this integration has increased the complexity and security challenges to all connected nodes. The IT servers of these hybrid networks are high-budget devices with tremendous processing power and significant storage capacity. In contrast, IoT nodes are low-cost devices with limited processing power and capacity. In addition, the ICS nodes are programmed for dedicated functions with the least interference. The available cybersecurity solutions for hybrid networks are either for specific node types or address particular weaknesses. Due to these distinct characteristics, these solutions may place other nodes in vulnerable positions. This study addresses this gap by proposing a comprehensive vulnerability modelling and mitigation strategy. This proposed solution equally applies to each node type of hybrid network while considering their unique characteristics. For this purpose, the industry-wide adoption of the Common Vulnerability Scoring System (CVSS) has been extended to embed the distinct characteristics of each node type in a hybrid network. To embed IoT features, the ‘attack vectors’ and ‘attack complexity vectors’ are modified and another metric “human safety index”, is integrated in the ‘Base metric group’ of CVSS. In addition, the ICS related characteristics are included in the ‘Environmental metric group’ of CVSS. This metric group is further enhanced to reflect the node resilience capabilities when evaluating the vulnerability score. The resilience of a node is evaluated by analysing the complex relationship of numerous contributing cyber security factors and practices. The evolved CVSSR-IoT-ICS framework proposed in the thesis measures the given vulnerabilities by adopting the unique dynamics of each node. These vulnerability scores are then mapped in the attack tree to reveal the critical nodes and shortest path to the target node. The mitigating strategy framework suggests the most efficient mitigation strategy to counter vulnerabilities by examining the node’s functionality, its locality, centrality, criticality, cascading impacts, available resources, and performance thresholds. Various case studies were conducted to analyse and evaluate our proposed vulnerability modelling and mitigation strategies on realistic supply chain systems. These analyses and evaluations confirm that the proposed solutions are highly effective for modelling the vulnerabilities while the mitigation strategies reduce the risks in dynamic and resource-constrained environments. The unified vulnerability modelling of hybrid networks minimises ambiguities, reduces complexities and identifies hidden deficiencies. It also improves system reliability and performance of heterogeneous networks while at the same time gaining acceptance for a universal vulnerability modelling framework across the cyber industry. The contributions have been published in reputable journals and conferences.
- Description: Doctor of Philosophy
- Authors: Ur-Rehman, Attiq
- Date: 2023
- Type: Text , Thesis , PhD
- Full Text:
- Description: Hybrid networks nowadays consist of traditional IT components, Internet of Things (IoT) and industrial control systems (ICS) nodes with varying characteristics, making them genuinely heterogeneous in nature. Historically evolving from traditional internet-enabled IT servers, hybrid networks allow organisations to strengthen cybersecurity, increase flexibility, improve efficiency, enhance reliability, boost remote connectivity and easy management. Though hybrid networks offer significant benefits from business and operational perspectives, this integration has increased the complexity and security challenges to all connected nodes. The IT servers of these hybrid networks are high-budget devices with tremendous processing power and significant storage capacity. In contrast, IoT nodes are low-cost devices with limited processing power and capacity. In addition, the ICS nodes are programmed for dedicated functions with the least interference. The available cybersecurity solutions for hybrid networks are either for specific node types or address particular weaknesses. Due to these distinct characteristics, these solutions may place other nodes in vulnerable positions. This study addresses this gap by proposing a comprehensive vulnerability modelling and mitigation strategy. This proposed solution equally applies to each node type of hybrid network while considering their unique characteristics. For this purpose, the industry-wide adoption of the Common Vulnerability Scoring System (CVSS) has been extended to embed the distinct characteristics of each node type in a hybrid network. To embed IoT features, the ‘attack vectors’ and ‘attack complexity vectors’ are modified and another metric “human safety index”, is integrated in the ‘Base metric group’ of CVSS. In addition, the ICS related characteristics are included in the ‘Environmental metric group’ of CVSS. This metric group is further enhanced to reflect the node resilience capabilities when evaluating the vulnerability score. The resilience of a node is evaluated by analysing the complex relationship of numerous contributing cyber security factors and practices. The evolved CVSSR-IoT-ICS framework proposed in the thesis measures the given vulnerabilities by adopting the unique dynamics of each node. These vulnerability scores are then mapped in the attack tree to reveal the critical nodes and shortest path to the target node. The mitigating strategy framework suggests the most efficient mitigation strategy to counter vulnerabilities by examining the node’s functionality, its locality, centrality, criticality, cascading impacts, available resources, and performance thresholds. Various case studies were conducted to analyse and evaluate our proposed vulnerability modelling and mitigation strategies on realistic supply chain systems. These analyses and evaluations confirm that the proposed solutions are highly effective for modelling the vulnerabilities while the mitigation strategies reduce the risks in dynamic and resource-constrained environments. The unified vulnerability modelling of hybrid networks minimises ambiguities, reduces complexities and identifies hidden deficiencies. It also improves system reliability and performance of heterogeneous networks while at the same time gaining acceptance for a universal vulnerability modelling framework across the cyber industry. The contributions have been published in reputable journals and conferences.
- Description: Doctor of Philosophy
Accurate prediction of sewer network flows and assessment of groundwater infiltration volumes in sewer networks
- Authors: Jayasooriya, Mahinda
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Excessive flows due to inflow and infiltration (I&I) in sewer networks contribute to hydraulically overloaded sanitary sewer networks. Understanding the cause–effect relationships associated with sewer network flow generation and accurate quantification of excessive flow volumes entering sewer networks is crucial to developing solutions to resolve this issue. A systematic literature review found a gap in understanding the cause–effect relationships of I&I and no universally accepted method for I&I estimation. This research used three years of data from an Australian sewer catchment in Ballarat, Victoria, as a case study to enhance understanding of the network flow generation process. The aims of this research were to accurately predict sewer network flows, reliably separate the groundwater infiltration (GWI) volume of sewer network flow, improve understanding of associated processes and identify the influential parameters that impact sewer network flow. This research used three methods to achieve these aims. First, commercially available software was used to develop and calibrate a sewer network model to predict flows with data from the case study catchment. The best practice guidelines available in Australia were used to calibrate the model, and a new method was introduced to separate the sewer network flow components. Second, two classical hydrology applications, the recursive filter and the flow duration curve (FDC) methods, were used to separate the GWI component of the total sewer network flow and understand the performance of the sewer catchments. Third, an artificial neural network (ANN) model was developed to predict sewer network flow. Parameters known to influence sewer flows were incrementally introduced to the ANN model to improve performance and understand their relative importance. This study finds that commercially available software can predict total sewer network flows with reasonable accuracy using the Wallingford or triangular hydrograph (RTK) hydrological implementation methods. However, the software cannot replicate the dynamic nature of the complex I&I processes that occur over time or reliably separate the sewer network flow components. A key finding from this study is that commercially available software has clear limitations in separating sewer network flow components. Recursive filter and FDC methods can be successfully used as standalone techniques to calculate the GWI volume. These methods have further value in comparing the I&I between catchments to determine flow characteristics and are straightforward for practising engineers to use. The ANN model predicts sewer flow with a high level of accuracy, and soil moisture is the most critical predictor of the total flow regime. The ANN model is also able to predict the dynamic and complex nature of I&I into sewer networks. More research is needed to achieve effective and reliable separation of individual components in an overall sewer flow regime. ANN and other emerging machine learning techniques show much potential to effectively predict sewer flows across a range of sewer network and catchment characteristics.
- Description: Doctor of Philosophy
- Authors: Jayasooriya, Mahinda
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Excessive flows due to inflow and infiltration (I&I) in sewer networks contribute to hydraulically overloaded sanitary sewer networks. Understanding the cause–effect relationships associated with sewer network flow generation and accurate quantification of excessive flow volumes entering sewer networks is crucial to developing solutions to resolve this issue. A systematic literature review found a gap in understanding the cause–effect relationships of I&I and no universally accepted method for I&I estimation. This research used three years of data from an Australian sewer catchment in Ballarat, Victoria, as a case study to enhance understanding of the network flow generation process. The aims of this research were to accurately predict sewer network flows, reliably separate the groundwater infiltration (GWI) volume of sewer network flow, improve understanding of associated processes and identify the influential parameters that impact sewer network flow. This research used three methods to achieve these aims. First, commercially available software was used to develop and calibrate a sewer network model to predict flows with data from the case study catchment. The best practice guidelines available in Australia were used to calibrate the model, and a new method was introduced to separate the sewer network flow components. Second, two classical hydrology applications, the recursive filter and the flow duration curve (FDC) methods, were used to separate the GWI component of the total sewer network flow and understand the performance of the sewer catchments. Third, an artificial neural network (ANN) model was developed to predict sewer network flow. Parameters known to influence sewer flows were incrementally introduced to the ANN model to improve performance and understand their relative importance. This study finds that commercially available software can predict total sewer network flows with reasonable accuracy using the Wallingford or triangular hydrograph (RTK) hydrological implementation methods. However, the software cannot replicate the dynamic nature of the complex I&I processes that occur over time or reliably separate the sewer network flow components. A key finding from this study is that commercially available software has clear limitations in separating sewer network flow components. Recursive filter and FDC methods can be successfully used as standalone techniques to calculate the GWI volume. These methods have further value in comparing the I&I between catchments to determine flow characteristics and are straightforward for practising engineers to use. The ANN model predicts sewer flow with a high level of accuracy, and soil moisture is the most critical predictor of the total flow regime. The ANN model is also able to predict the dynamic and complex nature of I&I into sewer networks. More research is needed to achieve effective and reliable separation of individual components in an overall sewer flow regime. ANN and other emerging machine learning techniques show much potential to effectively predict sewer flows across a range of sewer network and catchment characteristics.
- Description: Doctor of Philosophy
Adapting port cluster theory to contextualise the remarkable rise of the gold rushes port of Melbourne: 1851–1861
- Authors: Taylor, Peter
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: The research question that forms the basis of this thesis asks how and what drove the port of Melbourne to advance 30–50 years growth in less than ten during the 1850s gold era. To answer this question this thesis modifies and tests a new methodological approach to read the port’s growth driven by a close reading and evaluation of port cluster theory. Developed in the early 2000s the theory synthesises elements that constitute a port and operations through a wide range of components and activities. Recognising that a twenty-first-century port is not the same as a mid-nineteenth-century port, through advances brought on by a wide range of modern technologies, the theory has been historicised to dismantle the 1851–1861 gold era port of Melbourne to recognise its parts and how it was built. One of the tools to be enhanced and expanded for this is the cluster table of components and activities, providing specifics for activities undertaken at a mid-nineteenth-century port. A key constituent this propels the research forward when applied at Melbourne’s four ports of central Melbourne, Sandridge (Port Melbourne), Williamstown, Footscray and the Saltwater (Maribyrnong) River (combined). The argument is made that the ports evolved to be a port cluster reinforced by the exploration of specific themes of defence, security, river punts, entrepreneurs, ballast trade, quarrying, railways, noxious industries, shipwreck salvage, shipbuilding, ship repairs, tourism and wharf construction as topics. This thesis then uses the evidence gained to claim that the port did indeed evolve into a cluster port by 1861. The wider implication of this research is that a new framework exists for understanding the complexities of a mid-nineteenth-century port and how this can be done in a systematic way. For this methodology to demonstrate utility outside the port of Melbourne, requires further testing at sites within Australia, and worldwide, for confirmation of universality.
- Description: Doctor of Philosophy
- Authors: Taylor, Peter
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: The research question that forms the basis of this thesis asks how and what drove the port of Melbourne to advance 30–50 years growth in less than ten during the 1850s gold era. To answer this question this thesis modifies and tests a new methodological approach to read the port’s growth driven by a close reading and evaluation of port cluster theory. Developed in the early 2000s the theory synthesises elements that constitute a port and operations through a wide range of components and activities. Recognising that a twenty-first-century port is not the same as a mid-nineteenth-century port, through advances brought on by a wide range of modern technologies, the theory has been historicised to dismantle the 1851–1861 gold era port of Melbourne to recognise its parts and how it was built. One of the tools to be enhanced and expanded for this is the cluster table of components and activities, providing specifics for activities undertaken at a mid-nineteenth-century port. A key constituent this propels the research forward when applied at Melbourne’s four ports of central Melbourne, Sandridge (Port Melbourne), Williamstown, Footscray and the Saltwater (Maribyrnong) River (combined). The argument is made that the ports evolved to be a port cluster reinforced by the exploration of specific themes of defence, security, river punts, entrepreneurs, ballast trade, quarrying, railways, noxious industries, shipwreck salvage, shipbuilding, ship repairs, tourism and wharf construction as topics. This thesis then uses the evidence gained to claim that the port did indeed evolve into a cluster port by 1861. The wider implication of this research is that a new framework exists for understanding the complexities of a mid-nineteenth-century port and how this can be done in a systematic way. For this methodology to demonstrate utility outside the port of Melbourne, requires further testing at sites within Australia, and worldwide, for confirmation of universality.
- Description: Doctor of Philosophy
An evaluation of the effectiveness of a consumer-led educational program about stigma in mental illness and recovery attitudes among Mental Health Nurses
- Authors: Sreeram, Anju
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Fear, frustration and myths about mental illness engenders negative attitudes towards mental illness. Such negative attitudes impede the recovery of people diagnosed with mental illness. Despite an increasing emphasis on stigma and recovery-focused practices, evidence shows prejudicial attitudes towards mental illness and the recovery of people with mental illness among mental health professionals still exist. Anti-stigma initiatives and recovery-oriented interventions can aid in enhancing the attitudes of mental health professionals. Contact-based interventions have the greatest impact on attitudes among the mental health professionals including nurses. However, research regarding initiatives targeting stigma of mental illness and recovery attitudes among Mental Health Nurses working in the acute inpatient psychiatric units is limited. Therefore, the aim of the current study was to evaluate the effectiveness of a consumer-led education package on stigma about mental illness and recovery attitudes of Mental Health Nurses. A sequential explanatory mixed-method, with a pre-test and post-test design was used to evaluate the effect of consumer-led education. This research involved three phases. In the first phase, the study explored Mental Health Nurses' attitudes towards mental illness and recovery using surveys and non-participant observation. The second phase focused on the co-development and co-implementation of a consumer-led education package. The effectiveness of the intervention was evaluated using immediate post-test assessment and again three months later. The final phase focused on exploring the results obtained in the first and second phases of the study through an in-depth interview.
- Description: Doctor of Philosophy
- Authors: Sreeram, Anju
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Fear, frustration and myths about mental illness engenders negative attitudes towards mental illness. Such negative attitudes impede the recovery of people diagnosed with mental illness. Despite an increasing emphasis on stigma and recovery-focused practices, evidence shows prejudicial attitudes towards mental illness and the recovery of people with mental illness among mental health professionals still exist. Anti-stigma initiatives and recovery-oriented interventions can aid in enhancing the attitudes of mental health professionals. Contact-based interventions have the greatest impact on attitudes among the mental health professionals including nurses. However, research regarding initiatives targeting stigma of mental illness and recovery attitudes among Mental Health Nurses working in the acute inpatient psychiatric units is limited. Therefore, the aim of the current study was to evaluate the effectiveness of a consumer-led education package on stigma about mental illness and recovery attitudes of Mental Health Nurses. A sequential explanatory mixed-method, with a pre-test and post-test design was used to evaluate the effect of consumer-led education. This research involved three phases. In the first phase, the study explored Mental Health Nurses' attitudes towards mental illness and recovery using surveys and non-participant observation. The second phase focused on the co-development and co-implementation of a consumer-led education package. The effectiveness of the intervention was evaluated using immediate post-test assessment and again three months later. The final phase focused on exploring the results obtained in the first and second phases of the study through an in-depth interview.
- Description: Doctor of Philosophy
An investigation of heat stress epidemiology, prevention guidelines, and sporting environment
- Authors: Gonsalves, Marlon
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: As temperatures rise, the frequency of heatwaves, extreme summer heat and less night-time cooling increases. An uncontrolled increase in heat production affects performance and subsequently affects the health of the athlete resulting in exertional heat illness (EHI). EHI is a result of an uncontrollable rise in core body temperature arising from a thermoregulatory response. With rising temperatures, the risk of EHI when exercising or participating in sport increases. However, assessing the risk of EHI is contingent on accurate epidemiological data and addressing the risk of EHI is reliant on effective evidence-based interventions. This thesis assessed the risk of EHI through four interlinked studies: (ⅰ) an analysis of heat-related sports and leisure hospitalisations and emergency department presentations to determine trends in incidence rates and compare them with meteorological trends; (ⅱ) a document analysis of all sports and leisure activity heat-related injury prevention resources in Australia to develop an understanding of the content within those resources; (ⅲ) an investigation of surface temperatures of commonly used artificial sports surfaces to assess the risk posed by such surfaces and measure the differences in microclimates; and, (ⅳ) an assessment of the concordance of meteorological data of multiple artificial sports surfaces with meteorological data from the nearest Bureau of Meteorology (BOM) weather station and a local City of Ballarat (COB) environmental monitoring system (EMS). A total of 1055 heat injury hospitalisations and emergency department (ED) presentations were recorded between July 2008 and June 2018, which included 171 sport-related hospitalisations,139 ED presentations, 83 leisure-related hospitalisations and 662 ED presentations. There were significant correlations between ED presentations for heat-related sports injuries and mean, minimum and maximum temperature, mean and maximum temperature anomaly, summer maximum temperature, and summer maximum temperature anomaly. Three overarching categories emerged through the document analysis process: preventive strategies (n=299, 63.9%), risk factors (n=94, 20.1%), and treatment (n=75, 16.0%). Activity modification, which included information on rescheduling games and extra breaks, was the most common intervention. Cricket, soccer, swimming, and triathlon had the most complete set of heat resources. During the 2020–2021 summer period a total of 1245 measurements were recorded across five artificial sports surfaces: athletics, hockey, lawn bowls, soccer, tennis. The lawn bowls turf was the hottest surface with a mean surface temperature of 54.43 (± 13.46) °C. An increase in surface temperature corresponded to an increase in air temperature, wet bulb temperature and a decrease in relative humidity but the effect varied across the five surfaces. An increase in solar radiation and air temperature also corresponded to an increase in surface temperature. On all five surfaces measured, the BOM air temperatures were the lowest, followed by the on-site air temperatures and then the COB air temperatures on all surfaces. The highest Wet Bulb Globe Temperature (WBGT) measurements of 24.38 (± 2.39) °C were recorded by the COB sensor, while the lowest WBGT measurements 20.76 (± 1.99) °C were recorded by the BOM. There was a statistically significant difference in the WBGT categorisation between on-site estimate measurements and BOM measurements, p <0.001. The incidence of heat-related hospitalisations and ED presentations provides a baseline from which heat-related guidelines and interventions can be developed, evaluated, and modified. Heat resources considered in the document analysis suggest EHI is preventable if appropriate precautions are implemented. With a focus on preventing EHI, heat resources mainly provided recommendations on modifying activities and reducing exposure to extreme conditions. These results imply the EHI risk posed by artificial sport surfaces are not uniform and safety polices should be updated to reflect the link between air temperature and surface temperature. Understanding how surface temperature is influenced by air temperature, solar radiation and cloud cover allows for more accurate predictions of playing conditions on these artificial sport surfaces. Differences were observed between the individual meteorological measurements, the WBGT measurements and the heat stress categorisation. Overall, a significant discord existed for both individual meteorological variables and WBGT modelled from multiple sources of available data. The findings from this thesis have implications for athlete welfare and strengthening future interventions. Overall, this doctoral research project quantifies the scale of heat-related injuries, reviews the policies to address these heat-related injuries and provides new knowledge on the risk posed by artificial sports surfaces.
- Description: Doctor of Philosophy
- Description: As temperatures rise, the frequency of heatwaves, extreme summer heat and less night-time cooling increases. An uncontrolled increase in heat production affects performance and subsequently affects the health of the athlete resulting in exertional heat illness (EHI). EHI is a result of an uncontrollable rise in core body temperature arising from a thermoregulatory response. With rising temperatures, the risk of EHI when exercising or participating in sport increases. However, assessing the risk of EHI is contingent on accurate epidemiological data and addressing the risk of EHI is reliant on effective evidence-based interventions. This thesis assessed the risk of EHI through four interlinked studies: (
- Authors: Gonsalves, Marlon
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: As temperatures rise, the frequency of heatwaves, extreme summer heat and less night-time cooling increases. An uncontrolled increase in heat production affects performance and subsequently affects the health of the athlete resulting in exertional heat illness (EHI). EHI is a result of an uncontrollable rise in core body temperature arising from a thermoregulatory response. With rising temperatures, the risk of EHI when exercising or participating in sport increases. However, assessing the risk of EHI is contingent on accurate epidemiological data and addressing the risk of EHI is reliant on effective evidence-based interventions. This thesis assessed the risk of EHI through four interlinked studies: (ⅰ) an analysis of heat-related sports and leisure hospitalisations and emergency department presentations to determine trends in incidence rates and compare them with meteorological trends; (ⅱ) a document analysis of all sports and leisure activity heat-related injury prevention resources in Australia to develop an understanding of the content within those resources; (ⅲ) an investigation of surface temperatures of commonly used artificial sports surfaces to assess the risk posed by such surfaces and measure the differences in microclimates; and, (ⅳ) an assessment of the concordance of meteorological data of multiple artificial sports surfaces with meteorological data from the nearest Bureau of Meteorology (BOM) weather station and a local City of Ballarat (COB) environmental monitoring system (EMS). A total of 1055 heat injury hospitalisations and emergency department (ED) presentations were recorded between July 2008 and June 2018, which included 171 sport-related hospitalisations,139 ED presentations, 83 leisure-related hospitalisations and 662 ED presentations. There were significant correlations between ED presentations for heat-related sports injuries and mean, minimum and maximum temperature, mean and maximum temperature anomaly, summer maximum temperature, and summer maximum temperature anomaly. Three overarching categories emerged through the document analysis process: preventive strategies (n=299, 63.9%), risk factors (n=94, 20.1%), and treatment (n=75, 16.0%). Activity modification, which included information on rescheduling games and extra breaks, was the most common intervention. Cricket, soccer, swimming, and triathlon had the most complete set of heat resources. During the 2020–2021 summer period a total of 1245 measurements were recorded across five artificial sports surfaces: athletics, hockey, lawn bowls, soccer, tennis. The lawn bowls turf was the hottest surface with a mean surface temperature of 54.43 (± 13.46) °C. An increase in surface temperature corresponded to an increase in air temperature, wet bulb temperature and a decrease in relative humidity but the effect varied across the five surfaces. An increase in solar radiation and air temperature also corresponded to an increase in surface temperature. On all five surfaces measured, the BOM air temperatures were the lowest, followed by the on-site air temperatures and then the COB air temperatures on all surfaces. The highest Wet Bulb Globe Temperature (WBGT) measurements of 24.38 (± 2.39) °C were recorded by the COB sensor, while the lowest WBGT measurements 20.76 (± 1.99) °C were recorded by the BOM. There was a statistically significant difference in the WBGT categorisation between on-site estimate measurements and BOM measurements, p <0.001. The incidence of heat-related hospitalisations and ED presentations provides a baseline from which heat-related guidelines and interventions can be developed, evaluated, and modified. Heat resources considered in the document analysis suggest EHI is preventable if appropriate precautions are implemented. With a focus on preventing EHI, heat resources mainly provided recommendations on modifying activities and reducing exposure to extreme conditions. These results imply the EHI risk posed by artificial sport surfaces are not uniform and safety polices should be updated to reflect the link between air temperature and surface temperature. Understanding how surface temperature is influenced by air temperature, solar radiation and cloud cover allows for more accurate predictions of playing conditions on these artificial sport surfaces. Differences were observed between the individual meteorological measurements, the WBGT measurements and the heat stress categorisation. Overall, a significant discord existed for both individual meteorological variables and WBGT modelled from multiple sources of available data. The findings from this thesis have implications for athlete welfare and strengthening future interventions. Overall, this doctoral research project quantifies the scale of heat-related injuries, reviews the policies to address these heat-related injuries and provides new knowledge on the risk posed by artificial sports surfaces.
- Description: Doctor of Philosophy
- Description: As temperatures rise, the frequency of heatwaves, extreme summer heat and less night-time cooling increases. An uncontrolled increase in heat production affects performance and subsequently affects the health of the athlete resulting in exertional heat illness (EHI). EHI is a result of an uncontrollable rise in core body temperature arising from a thermoregulatory response. With rising temperatures, the risk of EHI when exercising or participating in sport increases. However, assessing the risk of EHI is contingent on accurate epidemiological data and addressing the risk of EHI is reliant on effective evidence-based interventions. This thesis assessed the risk of EHI through four interlinked studies: (
Are nurse academics technology ready? A mixed methods study of Australian nurse academics’ attitudes to technologies in teaching
- Authors: Browning, Mark
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Technology use in higher education teaching has become widespread and ubiquitous, affecting many areas of teaching and learning (Bond et al., 2020). Nurse education has been impacted by this shift with increasing use of technologies in the classroom (Koch, 2014). Although there has been a large research focus relating to students’ elearning, there has been less focus on the academic and their elearning role, in particular, how academic attitudes influence technology use in teaching (Drysdale et al., 2013; Martin, Polly, et al., 2020). The aim of this study was to explore nurse academics’ attitudes to technology and the influence attitude has on their use of technologies in teaching. There were three objectives: 1) To investigate nurse academics’ attitudes to technology through the Technology Readiness Index 2.0 (TRI 2). 2) To develop an understanding of how and why nurse academics engage with technology through individual interviews. 3) To integrate the quantitative (Objective 1) and qualitative (Objective 2) findings in order to gain a holistic understanding of academics’ use of technologies in teaching. A mixed methods sequential explanatory design consisting of two phases was used to address the aim. The first phase was a survey based on a previously validated, 16 item questionnaire, the Technology Readiness Index 2.0 (TRI 2), which was distributed to Australian nurse academics. The second phase included semi-structured individual interviews focussed on academics’ use and attitudes to technology, incorporating elements from the survey. The Technology Readiness Index 2.0 (TRI 2) was used in this study for the first time with nurse academics. The phase one findings indicate that nurse academics were technology ready, had higher overall TRI mean score than the general population (Parasuraman & Colby, 2015), but with similar outcomes to previous nurse academic research. Of note was that TRI was significantly associated with frequency of technology use, number of technologies used and self-rated confidence to use technology. The findings revealed three main Technology Readiness groups, representing three attitudes to technology in teaching: Explorers, Sceptics and Hesitators. Explorers were found to be innovative, positive and confident in their use of technology; Sceptics showed aversion to technology, were cautious when considering the impact on pedagogy and concerned about the impact on interpersonal skills; Hesitators showed preference for traditional teaching and distrust and were anxious about technology use. Overall, attitudes were found to be complex, based on experience and the potential impact technology may have on nursing students. The groups identified in this thesis explain behaviours and enable institutes to support academics in their engagement with technology. Recommendations include flexible training to meet the needs of academics, the use of simple and reliable technology across TR groups and adjusting workloads to account for the time-consuming nature of technology. There is also a need for academics to consider their attitudes to technology and the impact this may have on their teaching. This thesis demonstrates that technology engagement is not a binary choice but a complex process based on attitudes and other factors.
- Description: Doctor of Philosophy
- Authors: Browning, Mark
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Technology use in higher education teaching has become widespread and ubiquitous, affecting many areas of teaching and learning (Bond et al., 2020). Nurse education has been impacted by this shift with increasing use of technologies in the classroom (Koch, 2014). Although there has been a large research focus relating to students’ elearning, there has been less focus on the academic and their elearning role, in particular, how academic attitudes influence technology use in teaching (Drysdale et al., 2013; Martin, Polly, et al., 2020). The aim of this study was to explore nurse academics’ attitudes to technology and the influence attitude has on their use of technologies in teaching. There were three objectives: 1) To investigate nurse academics’ attitudes to technology through the Technology Readiness Index 2.0 (TRI 2). 2) To develop an understanding of how and why nurse academics engage with technology through individual interviews. 3) To integrate the quantitative (Objective 1) and qualitative (Objective 2) findings in order to gain a holistic understanding of academics’ use of technologies in teaching. A mixed methods sequential explanatory design consisting of two phases was used to address the aim. The first phase was a survey based on a previously validated, 16 item questionnaire, the Technology Readiness Index 2.0 (TRI 2), which was distributed to Australian nurse academics. The second phase included semi-structured individual interviews focussed on academics’ use and attitudes to technology, incorporating elements from the survey. The Technology Readiness Index 2.0 (TRI 2) was used in this study for the first time with nurse academics. The phase one findings indicate that nurse academics were technology ready, had higher overall TRI mean score than the general population (Parasuraman & Colby, 2015), but with similar outcomes to previous nurse academic research. Of note was that TRI was significantly associated with frequency of technology use, number of technologies used and self-rated confidence to use technology. The findings revealed three main Technology Readiness groups, representing three attitudes to technology in teaching: Explorers, Sceptics and Hesitators. Explorers were found to be innovative, positive and confident in their use of technology; Sceptics showed aversion to technology, were cautious when considering the impact on pedagogy and concerned about the impact on interpersonal skills; Hesitators showed preference for traditional teaching and distrust and were anxious about technology use. Overall, attitudes were found to be complex, based on experience and the potential impact technology may have on nursing students. The groups identified in this thesis explain behaviours and enable institutes to support academics in their engagement with technology. Recommendations include flexible training to meet the needs of academics, the use of simple and reliable technology across TR groups and adjusting workloads to account for the time-consuming nature of technology. There is also a need for academics to consider their attitudes to technology and the impact this may have on their teaching. This thesis demonstrates that technology engagement is not a binary choice but a complex process based on attitudes and other factors.
- Description: Doctor of Philosophy
Continuing professional development of allied health professionals : A regional study
- Authors: Schenk, Peter
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Background The Australian healthcare system is challenged by an ageing population and lifestyle risk factors that disproportionately affect people in regional (non-metropolitan) geographic regions. In addition, the allied health professionals who work in knowledge-intensive occupations in regional Victoria face barriers regarding profession related learning. Allied health professionals provide diagnostic and therapeutic patient care services, and within these professions, healthcare diagnoses and treatments are expected by society and government to be founded on scientific evidence. Therefore, remaining up-to-date with rapidly developing knowledge requires continuing professional development (CPD). Purpose This study explores pertinent issues affecting the CPD programs of allied health professionals and the interaction with regional Victorian public hospitals’ knowledge management (KM) approaches. Consequently, the study identifies opportunities for improving profession related learning, enhancing evidence-based practice and the efficacy of diagnoses and treatments. The proposed outcome of this study addresses perceived inadequacies of allied health professionals’ CPD and its contribution to medical errors. Furthermore, greater availability and effectiveness of profession related learning in these occupations should improve patients’ health outcomes. The study described in this thesis answers the primary research question: 1) What factors significantly influence the availability and effectiveness of continuing professional development (CPD) for allied health professionals (radiographers, sonographers and physiotherapists)? In addition, it also answers the secondary research question: 2) How can the findings of this research be represented to improve the CPD of allied health professionals and knowledge management (KM) in regional Victorian public hospitals? Methodology This study explores subjective phenomena involving human behaviour; therefore, the philosophical foundations of this study are post-positivist, with knowledge claims of interpretivist research. This research employs multi-site embedded case studies, defined as empirical enquiries investigating contemporary phenomena in real-world contexts. Therefore, they are suitable for this investigation, where participant experiences and contexts are equally important. Case selection in this study expresses regionalism through remoteness classifications of inner and outer regional areas, and hospital size comparing small/medium and large/referral regional hospitals. The 37 respondents to semi-structured interviews include hospital managers and purposefully selected allied health professionals (radiographers, sonographers and physiotherapists). The interviews were conducted from March to June 2017, with thematic analysis completed thereafter. Results Respondents in this study propose a holistic concept of CPD, encompassing all profession related learning opportunities, including learning from CPD activities and practice-based learning. Furthermore, the allied health professionals had various motivations for undertaking CPD, including maintaining and enhancing profession related knowledge, personal interest, supporting hospital needs, and meeting mandatory requirements. In addition, they discussed the factors that influenced their CPD planning, including their preference for formal face-to-face CPD activities, the availability of hospital-provided or local CPD activities, online learning, and overcoming barriers of their regional location. Finally, the factors influencing allied health professionals’ CPD include their planning of CPD programs, the influence of hospitals’ KM, and the competencies they consider necessary for good practice. Conclusion The thematic analysis in this study represents this study’s findings as a normative conceptual model in answer to the secondary research question. The Model of Allied Health Professionals’ CPD (described in section 6.7) proffers a heuristic framework depicting reflective feedback and the process of deliberative planning of CPD. Extrapolating knowledge from the literature and respondents’ experiences with CPD, the model’s elements include interrelationships between allied health professionals’ CPD planning and activities, hospitals’ approaches to KM, and informal workplace learning. Furthermore, the combined outcomes of CPD and KM contribute to allied health professionals’ competencies and expertise, presumably contributing to improving patients’ healthcare, including diagnoses and treatments.
- Description: Doctor of Philosophy
- Authors: Schenk, Peter
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Background The Australian healthcare system is challenged by an ageing population and lifestyle risk factors that disproportionately affect people in regional (non-metropolitan) geographic regions. In addition, the allied health professionals who work in knowledge-intensive occupations in regional Victoria face barriers regarding profession related learning. Allied health professionals provide diagnostic and therapeutic patient care services, and within these professions, healthcare diagnoses and treatments are expected by society and government to be founded on scientific evidence. Therefore, remaining up-to-date with rapidly developing knowledge requires continuing professional development (CPD). Purpose This study explores pertinent issues affecting the CPD programs of allied health professionals and the interaction with regional Victorian public hospitals’ knowledge management (KM) approaches. Consequently, the study identifies opportunities for improving profession related learning, enhancing evidence-based practice and the efficacy of diagnoses and treatments. The proposed outcome of this study addresses perceived inadequacies of allied health professionals’ CPD and its contribution to medical errors. Furthermore, greater availability and effectiveness of profession related learning in these occupations should improve patients’ health outcomes. The study described in this thesis answers the primary research question: 1) What factors significantly influence the availability and effectiveness of continuing professional development (CPD) for allied health professionals (radiographers, sonographers and physiotherapists)? In addition, it also answers the secondary research question: 2) How can the findings of this research be represented to improve the CPD of allied health professionals and knowledge management (KM) in regional Victorian public hospitals? Methodology This study explores subjective phenomena involving human behaviour; therefore, the philosophical foundations of this study are post-positivist, with knowledge claims of interpretivist research. This research employs multi-site embedded case studies, defined as empirical enquiries investigating contemporary phenomena in real-world contexts. Therefore, they are suitable for this investigation, where participant experiences and contexts are equally important. Case selection in this study expresses regionalism through remoteness classifications of inner and outer regional areas, and hospital size comparing small/medium and large/referral regional hospitals. The 37 respondents to semi-structured interviews include hospital managers and purposefully selected allied health professionals (radiographers, sonographers and physiotherapists). The interviews were conducted from March to June 2017, with thematic analysis completed thereafter. Results Respondents in this study propose a holistic concept of CPD, encompassing all profession related learning opportunities, including learning from CPD activities and practice-based learning. Furthermore, the allied health professionals had various motivations for undertaking CPD, including maintaining and enhancing profession related knowledge, personal interest, supporting hospital needs, and meeting mandatory requirements. In addition, they discussed the factors that influenced their CPD planning, including their preference for formal face-to-face CPD activities, the availability of hospital-provided or local CPD activities, online learning, and overcoming barriers of their regional location. Finally, the factors influencing allied health professionals’ CPD include their planning of CPD programs, the influence of hospitals’ KM, and the competencies they consider necessary for good practice. Conclusion The thematic analysis in this study represents this study’s findings as a normative conceptual model in answer to the secondary research question. The Model of Allied Health Professionals’ CPD (described in section 6.7) proffers a heuristic framework depicting reflective feedback and the process of deliberative planning of CPD. Extrapolating knowledge from the literature and respondents’ experiences with CPD, the model’s elements include interrelationships between allied health professionals’ CPD planning and activities, hospitals’ approaches to KM, and informal workplace learning. Furthermore, the combined outcomes of CPD and KM contribute to allied health professionals’ competencies and expertise, presumably contributing to improving patients’ healthcare, including diagnoses and treatments.
- Description: Doctor of Philosophy
Design and optimisation of the limaçon rotary compressor
- Lu, Kui
- Authors: Lu, Kui
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: The limaçon positive displacement machine is characterised by its internal geometry and unique mechanical motion; both based on a mathematical curve known as the limaçon of Pascal. The limaçon technology offers many advantages, such as compact size and double‐acting functionality, and its great potential for fluid processing applications has been proven by a number of patents and innovative designs in engines, expanders, and pumps. However, no commercial application of the limaçon technology in the field of positive displacement compressors has been reported in the literature. This could be attributed to the fact that the potential of the limaçon technology for gas compression has not been established as yet. The process of establishing potential is necessary before funds and resources are dedicated to investing in prototyping and testing. This process entails a considerable amount of modelling, coding and analysis as one must ensure the embodiment is geometrically capable of delivering suction and compression strokes, ports can be arranged to support the workings of these strokes, a number of measurable parameters can be identified as impacting compressor performance and it is possible to calculate a set of parameters which optimise this performance. To achieve this objective, a comprehensive mathematical model of a limaçon machine, implemented as a compressor,was first developed. The model, which is multi‐physical in nature, spans such domains as kinematics, fluid dynamics, characteristics of the port flow, internal leakage due to seal vibration, dynamics of the discharge valve, and thermodynamics. Subsequently, the simulation of the model has been performed to numerically study the operational characteristics of the limaçon compressor and to investigate the effect of various parameters on the compressor performance. It was found that the increase in the operating speed and pressure ratio would lead to negative effects on machine performance, especially on volumetric efficiency. Additionally, the results of simulations indicated that the level of fluid over‐compression is influenced by the characteristics of the discharge valve. To ensure the suitability of limaçon technology for use in positive displacement compressors, a study was undertaken to determine whether such an embodiment lent itself to optimisation efforts. For this purpose, the thorough mathematical model which has been developed to simulate compressor workings was then used for optimisation purposes whereby a Bayesian optimisation procedure was applied. The optimisation procedure was conducted in a two‐stage fashion where the first stage optimises the machine dimensions to meet volumetric requirements specified by the designer; and the second stage focuses on revealing the optimum combination of port geometries that improves machine performance. A numerical illustration was presented to prove the validity of the presented approach, and the results show that considerable improvements in the isentropic and volumetric efficiencies can be attained. Moreover, the optimised design was tested under different operating speeds and pressure ratios to investigate its robustness. It was found that the optimised design can exhibit relatively stable performance when the working conditions vary within a small bandwidth around that used in the optimisation procedure. The limaçon technology has three embodiments, namely the limaçon‐to‐limaçon (L2L), the limaçon‐to‐circular, and the circolimaçon. The circolimaçon embodiment features using circular arcs, rather than limaçon curves, to develop profiles for the rotor and housing. This embodiment simplifies the manufacturing process and reduces the production cost associated with producing a limaçon technology. A feasibility study of the circolimaçon embodiment was conducted by comparing its performance with that of the L2L type device. The machine dimensions and port geometries obtained from the optimisation procedure were used in the comparative study. A nonlinear three‐degree of freedom model was presented to describe the dynamic behaviour of the apex seal during the machine operation. Additionally, the leakage through the seal‐housing gap was formulated by considering the inertia and viscous effects of the flow. The results from the case study suggest that the circolimaçon embodiment exhibits comparable performance to the L2L‐type machine, despite having more significant seal vibrations. Moreover, it was also discovered that the circolimaçon compressor with a small capacity undergoes a lower level of seal dynamics, indicating better machine reliability.
- Description: Doctor of Philosophy
- Authors: Lu, Kui
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: The limaçon positive displacement machine is characterised by its internal geometry and unique mechanical motion; both based on a mathematical curve known as the limaçon of Pascal. The limaçon technology offers many advantages, such as compact size and double‐acting functionality, and its great potential for fluid processing applications has been proven by a number of patents and innovative designs in engines, expanders, and pumps. However, no commercial application of the limaçon technology in the field of positive displacement compressors has been reported in the literature. This could be attributed to the fact that the potential of the limaçon technology for gas compression has not been established as yet. The process of establishing potential is necessary before funds and resources are dedicated to investing in prototyping and testing. This process entails a considerable amount of modelling, coding and analysis as one must ensure the embodiment is geometrically capable of delivering suction and compression strokes, ports can be arranged to support the workings of these strokes, a number of measurable parameters can be identified as impacting compressor performance and it is possible to calculate a set of parameters which optimise this performance. To achieve this objective, a comprehensive mathematical model of a limaçon machine, implemented as a compressor,was first developed. The model, which is multi‐physical in nature, spans such domains as kinematics, fluid dynamics, characteristics of the port flow, internal leakage due to seal vibration, dynamics of the discharge valve, and thermodynamics. Subsequently, the simulation of the model has been performed to numerically study the operational characteristics of the limaçon compressor and to investigate the effect of various parameters on the compressor performance. It was found that the increase in the operating speed and pressure ratio would lead to negative effects on machine performance, especially on volumetric efficiency. Additionally, the results of simulations indicated that the level of fluid over‐compression is influenced by the characteristics of the discharge valve. To ensure the suitability of limaçon technology for use in positive displacement compressors, a study was undertaken to determine whether such an embodiment lent itself to optimisation efforts. For this purpose, the thorough mathematical model which has been developed to simulate compressor workings was then used for optimisation purposes whereby a Bayesian optimisation procedure was applied. The optimisation procedure was conducted in a two‐stage fashion where the first stage optimises the machine dimensions to meet volumetric requirements specified by the designer; and the second stage focuses on revealing the optimum combination of port geometries that improves machine performance. A numerical illustration was presented to prove the validity of the presented approach, and the results show that considerable improvements in the isentropic and volumetric efficiencies can be attained. Moreover, the optimised design was tested under different operating speeds and pressure ratios to investigate its robustness. It was found that the optimised design can exhibit relatively stable performance when the working conditions vary within a small bandwidth around that used in the optimisation procedure. The limaçon technology has three embodiments, namely the limaçon‐to‐limaçon (L2L), the limaçon‐to‐circular, and the circolimaçon. The circolimaçon embodiment features using circular arcs, rather than limaçon curves, to develop profiles for the rotor and housing. This embodiment simplifies the manufacturing process and reduces the production cost associated with producing a limaçon technology. A feasibility study of the circolimaçon embodiment was conducted by comparing its performance with that of the L2L type device. The machine dimensions and port geometries obtained from the optimisation procedure were used in the comparative study. A nonlinear three‐degree of freedom model was presented to describe the dynamic behaviour of the apex seal during the machine operation. Additionally, the leakage through the seal‐housing gap was formulated by considering the inertia and viscous effects of the flow. The results from the case study suggest that the circolimaçon embodiment exhibits comparable performance to the L2L‐type machine, despite having more significant seal vibrations. Moreover, it was also discovered that the circolimaçon compressor with a small capacity undergoes a lower level of seal dynamics, indicating better machine reliability.
- Description: Doctor of Philosophy
Ecology and management of a tropical invasive weed, Cyperus aromaticus (Navua sedge) in Queensland, Australia
- Authors: Chadha, Aakansha
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Cyperus aromaticus (Ridley) Mattf. & Kükenth, commonly known as Navua sedge is an invasive C4 perennial sedge species of the Cyperaceae family found predominantly in tropical environments. A native of tropical Africa, it has spread widely and become problematic in many southwest Pacific islands and in tropical north Queensland, Australia. It is a principal weed infesting pastures, sugarcane, banana and root crops, which causes significant damage across a range of industries including dairy, beef, sugarcane and banana in the highly fertile and productive areas of Queensland. The primary objective of this thesis was to contribute to a significant weed management problem at a stage where intervention is cost effective, efficient and environmentally sensitive. At the centre of this work, was a contribution to fundamental knowledge regarding the ecology of the species. The first objective was to examine the global literature on rhizomatous weeds and C. aromaticus in particular to identify the research problems and knowledge gaps. As C. aromaticus has dual mode of reproduction, via seeds and rhizomes, both these aspects were taken into consideration in the experimental chapters. The project critically addressed the issues related to (i) understanding the fundamental ecological aspects of reproduction via seeds in C. aromaticus, (ii) the regeneration of C. aromaticus from its rhizomes, and (iii) control of C. aromaticus using herbicides. A stepwise approach, involving multiple objectives was used to meet the primary objective of this project. Three experiments were conducted to understand the fundamental ecological aspects of reproduction via seeds. (i) A study was conducted to understand the soil seed bank dynamics of pastures invaded by C. aromaticus. It was found that C. aromaticus is the dominant species in the soil seed bank of pastures invaded by C. aromaticus and can contribute between 62% and 95% of the total seed bank. In this respect, the abundance of C. aromaticus seed in the soil seed bank is positively correlated with the aboveground biomass of C. aromaticus and 83% of the total C. aromaticus seeds was found in the top 0-5 cm layer of soil. (ii) The lifespan of C. aromaticus seeds was estimated by artificial ageing technique in the laboratory whereby the results indicate that long-term management is required to control the recruitment from the soil seed bank even in the absence of additional seed deposition. (iii) Seed germination ecology was investigated to understand the effect of various environmental factors on the germination of C. aromaticus seeds. It was found that light is absolutely required for C. aromaticus seed germination, and there was no germination of seeds above 150 mM NaCl concentration and -0.8 Mpa osmotic potential, or from seeds buried greater than 2 cm below the soil surface. Focussing on the regeneration from C. aromaticus rhizomes, an experiment was conducted to investigate the effect of rhizome size and burial depth on the emergence from rhizomes in different soil types. A positive correlation was found between the total emergence of tillers and rhizome fragment size of C. aromaticus, but a negative correlation was found between the total emergence of tillers and burial depth of rhizomes. Importantly, it was also found that rhizomes when reduced to 10 cm or smaller fragments and buried 15 cm or deeper will prevent emergence. A further two glasshouse experiments were conducted to explore chemical options to control both the aboveground biomass and the belowground rhizomes. (i) The herbicide sensitivity of various rates of halosulfuron-methyl was evaluated at different growth stages using plants with and without established rhizomes. Mortality of 27.5%, 0% and 5% was recorded when treated with 75 g ai ha-1 of halosulfuron-methyl at the mowed, pre-flowering and flowering stages, respectively in plants with established rhizomes. The herbicide was effective in controlling the aboveground growth, however, subsequent emergence of new growth from the rhizome confirms the failure of the herbicide to kill the rhizome. In contrast, application of 75 g ai ha-1 of halosulfuron-methyl provided 100% mortality in plants treated at seedling and pre-flowering stage in plants without established rhizomes. (ii) Another herbicide with an alternate mode of action, florpyrauxifen-benzyl, was assessed at different growth stages again using plants with and without established rhizomes. Results indicate that a single application of florpyrauxifen-benzyl is effective at controlling C. aromaticus seedlings, but not effective at controlling plants with established rhizomes. In summary, this thesis has increased the fundamental knowledge about the ecology of C. aromaticus which will feed into designing of management strategies. Likewise, new tools established in the form of mechanical and chemical control and improving the methods currently used to manage populations will advance the capacity to effectively manage C. aromaticus in the future. Although this investigation is based on a relatively focussed suite of issues relevant to tropical north Queensland, where there is an immediate application of the research outcomes from this study, it is anticipated that they will also inform weed management strategies more broadly in a range of similar environments throughout the world.
- Description: Doctor of Philosophy
- Authors: Chadha, Aakansha
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Cyperus aromaticus (Ridley) Mattf. & Kükenth, commonly known as Navua sedge is an invasive C4 perennial sedge species of the Cyperaceae family found predominantly in tropical environments. A native of tropical Africa, it has spread widely and become problematic in many southwest Pacific islands and in tropical north Queensland, Australia. It is a principal weed infesting pastures, sugarcane, banana and root crops, which causes significant damage across a range of industries including dairy, beef, sugarcane and banana in the highly fertile and productive areas of Queensland. The primary objective of this thesis was to contribute to a significant weed management problem at a stage where intervention is cost effective, efficient and environmentally sensitive. At the centre of this work, was a contribution to fundamental knowledge regarding the ecology of the species. The first objective was to examine the global literature on rhizomatous weeds and C. aromaticus in particular to identify the research problems and knowledge gaps. As C. aromaticus has dual mode of reproduction, via seeds and rhizomes, both these aspects were taken into consideration in the experimental chapters. The project critically addressed the issues related to (i) understanding the fundamental ecological aspects of reproduction via seeds in C. aromaticus, (ii) the regeneration of C. aromaticus from its rhizomes, and (iii) control of C. aromaticus using herbicides. A stepwise approach, involving multiple objectives was used to meet the primary objective of this project. Three experiments were conducted to understand the fundamental ecological aspects of reproduction via seeds. (i) A study was conducted to understand the soil seed bank dynamics of pastures invaded by C. aromaticus. It was found that C. aromaticus is the dominant species in the soil seed bank of pastures invaded by C. aromaticus and can contribute between 62% and 95% of the total seed bank. In this respect, the abundance of C. aromaticus seed in the soil seed bank is positively correlated with the aboveground biomass of C. aromaticus and 83% of the total C. aromaticus seeds was found in the top 0-5 cm layer of soil. (ii) The lifespan of C. aromaticus seeds was estimated by artificial ageing technique in the laboratory whereby the results indicate that long-term management is required to control the recruitment from the soil seed bank even in the absence of additional seed deposition. (iii) Seed germination ecology was investigated to understand the effect of various environmental factors on the germination of C. aromaticus seeds. It was found that light is absolutely required for C. aromaticus seed germination, and there was no germination of seeds above 150 mM NaCl concentration and -0.8 Mpa osmotic potential, or from seeds buried greater than 2 cm below the soil surface. Focussing on the regeneration from C. aromaticus rhizomes, an experiment was conducted to investigate the effect of rhizome size and burial depth on the emergence from rhizomes in different soil types. A positive correlation was found between the total emergence of tillers and rhizome fragment size of C. aromaticus, but a negative correlation was found between the total emergence of tillers and burial depth of rhizomes. Importantly, it was also found that rhizomes when reduced to 10 cm or smaller fragments and buried 15 cm or deeper will prevent emergence. A further two glasshouse experiments were conducted to explore chemical options to control both the aboveground biomass and the belowground rhizomes. (i) The herbicide sensitivity of various rates of halosulfuron-methyl was evaluated at different growth stages using plants with and without established rhizomes. Mortality of 27.5%, 0% and 5% was recorded when treated with 75 g ai ha-1 of halosulfuron-methyl at the mowed, pre-flowering and flowering stages, respectively in plants with established rhizomes. The herbicide was effective in controlling the aboveground growth, however, subsequent emergence of new growth from the rhizome confirms the failure of the herbicide to kill the rhizome. In contrast, application of 75 g ai ha-1 of halosulfuron-methyl provided 100% mortality in plants treated at seedling and pre-flowering stage in plants without established rhizomes. (ii) Another herbicide with an alternate mode of action, florpyrauxifen-benzyl, was assessed at different growth stages again using plants with and without established rhizomes. Results indicate that a single application of florpyrauxifen-benzyl is effective at controlling C. aromaticus seedlings, but not effective at controlling plants with established rhizomes. In summary, this thesis has increased the fundamental knowledge about the ecology of C. aromaticus which will feed into designing of management strategies. Likewise, new tools established in the form of mechanical and chemical control and improving the methods currently used to manage populations will advance the capacity to effectively manage C. aromaticus in the future. Although this investigation is based on a relatively focussed suite of issues relevant to tropical north Queensland, where there is an immediate application of the research outcomes from this study, it is anticipated that they will also inform weed management strategies more broadly in a range of similar environments throughout the world.
- Description: Doctor of Philosophy
Efficient texture descriptors for image segmentation
- Authors: Tania, Sheikh
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Colour and texture are the most common features used in image processing and computer vision applications. Unlike colour, a local texture descriptor needs to express the unique variation pattern in the intensity differences of pixels in the neighbourhood of the pixel-of-interest (POI) so that it can sufficiently discriminate different textures. Since the descriptor needs spatial manipulation of all pixels in the neighbourhood of the POI, approximation of texture impacts not only the computational cost but also the performance of the applications. In this thesis, we aim to develop novel texture descriptors, especially for hierarchical image segmentation techniques that have recently gained popularity for their wide range of applications in medical imaging, video surveillance, autonomous navigation, and computer vision in general. To pursue the aim, we focus in reducing the length of the texture feature and directly modelling the distribution of intensity-variation in the parametric space of a probability density function (pdf). In the first contributory chapter, we enhance the state-of-the-art Weber local descriptor (WLD) by considering the mean value of neighbouring pixel intensities along radial directions instead of sampling pixels at three scales. Consequently, the proposed descriptor, named Radial Mean WLD (RM-WLD), is three-fold shorter than WLD and it performs slightly better than WLD in hierarchical image segmentation. The statistical distributions of pixel intensities in different image regions are diverse by nature. In the second contributory chapter, we propose a novel texture feature, called ‘joint scale,’ by directly modelling the probability distribution of intensity differences. The Weibull distribution, one of the extreme value distributions, is selected for this purpose as it can represent a wide range of probability distributions with a couple of parameters. In addition, gradient orientation feature is calculated from all pixels in the neighbourhood with an extended Sobel operator, instead of using only the vertical and horizontal neighbours as considered in WLD. The length of the texture descriptor combining joint scale and gradiet orientation features remains the same as RM-WLD, but it exhibits significantly improved discrimination capability for better image segmentation. Initial regions in hierarchical segmentation play an important role in approximating texture features. Traditional arbitrary-shaped initial regions maintain the uniform colour property and thus may not retain the texture pattern of the segment they belong to. In the final contributory chapter, we introduce regular-shaped initial regions by enhancing the cuboidal partitioning technique, which has recently gained popularity in image/video coding research. Since the regions (cuboids) of cuboidal partitioning are of rectangular shape, they do not follow the colour-based boundary adherence of traditional initial regions. Consequently, the cuboids retain sufficient texture pattern cues to provide better texture approximation and discriminating capability. We have used benchmark segmentation datasets and metrics to evaluate the proposed texture descriptors. Experimental results on benchmark metrics and computational time are promising when the proposed texture features are used in the state-of-the-art iterative contraction and merging (ICM) image segmentation technique.
- Description: Doctor of Philosophy
- Authors: Tania, Sheikh
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Colour and texture are the most common features used in image processing and computer vision applications. Unlike colour, a local texture descriptor needs to express the unique variation pattern in the intensity differences of pixels in the neighbourhood of the pixel-of-interest (POI) so that it can sufficiently discriminate different textures. Since the descriptor needs spatial manipulation of all pixels in the neighbourhood of the POI, approximation of texture impacts not only the computational cost but also the performance of the applications. In this thesis, we aim to develop novel texture descriptors, especially for hierarchical image segmentation techniques that have recently gained popularity for their wide range of applications in medical imaging, video surveillance, autonomous navigation, and computer vision in general. To pursue the aim, we focus in reducing the length of the texture feature and directly modelling the distribution of intensity-variation in the parametric space of a probability density function (pdf). In the first contributory chapter, we enhance the state-of-the-art Weber local descriptor (WLD) by considering the mean value of neighbouring pixel intensities along radial directions instead of sampling pixels at three scales. Consequently, the proposed descriptor, named Radial Mean WLD (RM-WLD), is three-fold shorter than WLD and it performs slightly better than WLD in hierarchical image segmentation. The statistical distributions of pixel intensities in different image regions are diverse by nature. In the second contributory chapter, we propose a novel texture feature, called ‘joint scale,’ by directly modelling the probability distribution of intensity differences. The Weibull distribution, one of the extreme value distributions, is selected for this purpose as it can represent a wide range of probability distributions with a couple of parameters. In addition, gradient orientation feature is calculated from all pixels in the neighbourhood with an extended Sobel operator, instead of using only the vertical and horizontal neighbours as considered in WLD. The length of the texture descriptor combining joint scale and gradiet orientation features remains the same as RM-WLD, but it exhibits significantly improved discrimination capability for better image segmentation. Initial regions in hierarchical segmentation play an important role in approximating texture features. Traditional arbitrary-shaped initial regions maintain the uniform colour property and thus may not retain the texture pattern of the segment they belong to. In the final contributory chapter, we introduce regular-shaped initial regions by enhancing the cuboidal partitioning technique, which has recently gained popularity in image/video coding research. Since the regions (cuboids) of cuboidal partitioning are of rectangular shape, they do not follow the colour-based boundary adherence of traditional initial regions. Consequently, the cuboids retain sufficient texture pattern cues to provide better texture approximation and discriminating capability. We have used benchmark segmentation datasets and metrics to evaluate the proposed texture descriptors. Experimental results on benchmark metrics and computational time are promising when the proposed texture features are used in the state-of-the-art iterative contraction and merging (ICM) image segmentation technique.
- Description: Doctor of Philosophy
Enhancing Culturally and Linguistically Diverse (CALD) community understanding and utilisation of mental health services in Victoria
- Authors: Radhamony, Reshmy
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: The increase in cultural diversity (CD) in Victoria, Australia, demands healthcare professionals to acquire cultural competence. Literature reveals that people from Culturally and Linguistically Diverse (CALD) communities can be disadvantaged in terms of mental health service access and utilisation and the appropriateness of the health care they receive following access. Cultural competence has been advocated as a necessary step to alleviate health disparities and reduce bias and prejudices associated with culturally diverse people. Cultural competence has been endorsed in the government and professional bodies’ policies and guidelines for a long time. Whether this has prepared the mental health nursing workforce with sufficient knowledge, skills, and attitude necessary to be culturally competent, is still questionable. Evidence shows that significant barriers such as language and communication, cultural differences, and a lack of cultural sensitivity by mental health nurses (MHN) limit the quality of care provided to people from various non-dominant cultures. The primary aim of this study was to examine whether an educational intervention can improve mental health nurses' knowledge, behaviour, and attitude. Hence this multiple-method study focused on the educational needs of a cross-section of MHNs in Victoria, utilising online surveys and semi-structured interviews. This project undertook a gap analysis through telephone interviews with the CALD community members in Victoria regarding their mental health service needs and experiences. Then developed, implemented, and evaluated an online education package – “Acknowledging Diversity”, regarding cultural awareness and responsiveness for mental health nurses working with people from CALD communities. A CIPP (Context, Input, Process and Product) model evaluation of the education package confirmed its effectiveness. Andersen's Behavioural Model of Health service use (ABMHSU) was the underlying theoretical framework for this study. The study's findings were further analysed using the contextual variables of Andersen’s model. The study outcome for mental health nurses was improved knowledge, attitude, and competence about the needs of people from CALD backgrounds, even though the findings were not statistically significant. However, it has been conceded that cultural competence cannot be achieved in a single education session. Therefore, attaining cultural proficiency is a continuous process that requires motivation and persistence from MHNs and ongoing cultural encounters with the CALD population. Examining how educational interventions improved MHNs’ cultural competency to facilitate CALD community understanding and utilisation of mental health services also identified the gaps in knowledge to report future research areas.
- Description: Doctor of Philosophy
- Authors: Radhamony, Reshmy
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: The increase in cultural diversity (CD) in Victoria, Australia, demands healthcare professionals to acquire cultural competence. Literature reveals that people from Culturally and Linguistically Diverse (CALD) communities can be disadvantaged in terms of mental health service access and utilisation and the appropriateness of the health care they receive following access. Cultural competence has been advocated as a necessary step to alleviate health disparities and reduce bias and prejudices associated with culturally diverse people. Cultural competence has been endorsed in the government and professional bodies’ policies and guidelines for a long time. Whether this has prepared the mental health nursing workforce with sufficient knowledge, skills, and attitude necessary to be culturally competent, is still questionable. Evidence shows that significant barriers such as language and communication, cultural differences, and a lack of cultural sensitivity by mental health nurses (MHN) limit the quality of care provided to people from various non-dominant cultures. The primary aim of this study was to examine whether an educational intervention can improve mental health nurses' knowledge, behaviour, and attitude. Hence this multiple-method study focused on the educational needs of a cross-section of MHNs in Victoria, utilising online surveys and semi-structured interviews. This project undertook a gap analysis through telephone interviews with the CALD community members in Victoria regarding their mental health service needs and experiences. Then developed, implemented, and evaluated an online education package – “Acknowledging Diversity”, regarding cultural awareness and responsiveness for mental health nurses working with people from CALD communities. A CIPP (Context, Input, Process and Product) model evaluation of the education package confirmed its effectiveness. Andersen's Behavioural Model of Health service use (ABMHSU) was the underlying theoretical framework for this study. The study's findings were further analysed using the contextual variables of Andersen’s model. The study outcome for mental health nurses was improved knowledge, attitude, and competence about the needs of people from CALD backgrounds, even though the findings were not statistically significant. However, it has been conceded that cultural competence cannot be achieved in a single education session. Therefore, attaining cultural proficiency is a continuous process that requires motivation and persistence from MHNs and ongoing cultural encounters with the CALD population. Examining how educational interventions improved MHNs’ cultural competency to facilitate CALD community understanding and utilisation of mental health services also identified the gaps in knowledge to report future research areas.
- Description: Doctor of Philosophy
Enhancing illusionism within the encased contemporary art diorama through the integration of screen-based animated film
- Authors: Kronberger, Kenneth
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: In the late nineteen eighties artists started to create a highly illusionistic type of small scaled diorama, which I refer to as the encased contemporary art diorama. Such dioramas are typically presented encased in a box-like structure with a glazed viewing window situated at the front. Artifice such as realistically coloured and shaped miniature forms, strategically positioned mirrors and quantified atmospheric lighting are used to enhance the verisimilitude of the mimetic resemblance to life-sized reality. As a maker of animated films, I became curious about the ways in which illusionism within such dioramas might be enhanced through the integration of screen-based animated film. To pursue this line of enquiry, I first strove to understand how illusionism functions within encased contemporary art dioramas, and I travelled to Lyon, France to view an exhibition of such dioramas at the Musee Miniature et Cinema. As there is an apparent lack of text on how illusionism functions within such dioramas, I modelled my initial research on texts about illusionism in representational pictures, how artists create visual illusions and the role of the viewer in the formation and perception of illusions. I engaged the writing of Michael Fish to assist in identifying different illusion types. To fully view the interior of an encased contemporary art diorama, the viewer must alter the location of their eyes in relation to the diorama and its contents, concurrently the encasement prevents any tactile appraisal of the diorama’s contents. I refer to Maurice Merleau-Ponty’s phenomenology of embodiment to account for the ways the viewer’s embodiment can influence their perception of dioramic illusions. The outcomes of my studio practice include animated films, and dioramas both with and without screen-based animated film integrated within them. The resulting illusions achieved are appraised and discussed, limitations are identified, and future potentials contemplated.
- Description: Doctor of Philosophy
- Authors: Kronberger, Kenneth
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: In the late nineteen eighties artists started to create a highly illusionistic type of small scaled diorama, which I refer to as the encased contemporary art diorama. Such dioramas are typically presented encased in a box-like structure with a glazed viewing window situated at the front. Artifice such as realistically coloured and shaped miniature forms, strategically positioned mirrors and quantified atmospheric lighting are used to enhance the verisimilitude of the mimetic resemblance to life-sized reality. As a maker of animated films, I became curious about the ways in which illusionism within such dioramas might be enhanced through the integration of screen-based animated film. To pursue this line of enquiry, I first strove to understand how illusionism functions within encased contemporary art dioramas, and I travelled to Lyon, France to view an exhibition of such dioramas at the Musee Miniature et Cinema. As there is an apparent lack of text on how illusionism functions within such dioramas, I modelled my initial research on texts about illusionism in representational pictures, how artists create visual illusions and the role of the viewer in the formation and perception of illusions. I engaged the writing of Michael Fish to assist in identifying different illusion types. To fully view the interior of an encased contemporary art diorama, the viewer must alter the location of their eyes in relation to the diorama and its contents, concurrently the encasement prevents any tactile appraisal of the diorama’s contents. I refer to Maurice Merleau-Ponty’s phenomenology of embodiment to account for the ways the viewer’s embodiment can influence their perception of dioramic illusions. The outcomes of my studio practice include animated films, and dioramas both with and without screen-based animated film integrated within them. The resulting illusions achieved are appraised and discussed, limitations are identified, and future potentials contemplated.
- Description: Doctor of Philosophy
Evaluating explanations of artificial intelligence decisions : the explanation quality rubric and survey
- Authors: Young, Charlotte
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: The use of Artificial Intelligence (AI) algorithms is growing rapidly (Vilone & Longo, 2020). With this comes an increasing demand for reliable, robust explanations of AI decisions. There is a pressing need for a way to evaluate their quality. This thesis examines these research questions: What would a rigorous, empirically justified, human-centred scheme for evaluating AI-decision explanations look like? How can a rigorous, empirically justified, human-centred scheme for evaluating AI-decision explanations be created? Can a rigorous, empirically justified, human-centred scheme for evaluating AI-decision explanations be used to improve explanations? Current Explainable Artificial Intelligence (XAI) research lacks an accepted, widely employed method for evaluating AI explanations. This thesis offers a method for creating a rigorous, empirically justified, human-centred scheme for evaluating AI-decision explanations. It uses this to create an evaluation methodology, the XQ Rubric and XQ Survey. The XQ Rubric and Survey are then employed to improve explanations of AI decisions. The thesis asks what constitutes a good explanation in the context of XAI. It provides: 1. a model of good explanation for use in XAI research 2. a method of gathering non-expert evaluations of XAI explanations 3. an evaluation scheme for non-experts to employ in assessing XAI explanations (XQ Rubric and XQ Survey). The thesis begins with a literature review, primarily an exploration of previous attempts to evaluate XAI explanations formally. This is followed by an account of the development and iterative refinement of a solution to the problem, the eXplanation Quality Rubric (XQ Rubric). A Design Science methodology was used to guide the XQ Rubric and XQ Survey development. The thesis limits itself to XAI explanations appropriate for non-experts. It proposes and tests an evaluation rubric and survey method that is both stable and robust: that is, readily usable and consistently reliable in a variety of XAI-explanation tasks.
- Description: Doctor of Philosophy
- Authors: Young, Charlotte
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: The use of Artificial Intelligence (AI) algorithms is growing rapidly (Vilone & Longo, 2020). With this comes an increasing demand for reliable, robust explanations of AI decisions. There is a pressing need for a way to evaluate their quality. This thesis examines these research questions: What would a rigorous, empirically justified, human-centred scheme for evaluating AI-decision explanations look like? How can a rigorous, empirically justified, human-centred scheme for evaluating AI-decision explanations be created? Can a rigorous, empirically justified, human-centred scheme for evaluating AI-decision explanations be used to improve explanations? Current Explainable Artificial Intelligence (XAI) research lacks an accepted, widely employed method for evaluating AI explanations. This thesis offers a method for creating a rigorous, empirically justified, human-centred scheme for evaluating AI-decision explanations. It uses this to create an evaluation methodology, the XQ Rubric and XQ Survey. The XQ Rubric and Survey are then employed to improve explanations of AI decisions. The thesis asks what constitutes a good explanation in the context of XAI. It provides: 1. a model of good explanation for use in XAI research 2. a method of gathering non-expert evaluations of XAI explanations 3. an evaluation scheme for non-experts to employ in assessing XAI explanations (XQ Rubric and XQ Survey). The thesis begins with a literature review, primarily an exploration of previous attempts to evaluate XAI explanations formally. This is followed by an account of the development and iterative refinement of a solution to the problem, the eXplanation Quality Rubric (XQ Rubric). A Design Science methodology was used to guide the XQ Rubric and XQ Survey development. The thesis limits itself to XAI explanations appropriate for non-experts. It proposes and tests an evaluation rubric and survey method that is both stable and robust: that is, readily usable and consistently reliable in a variety of XAI-explanation tasks.
- Description: Doctor of Philosophy
Every crypto breath in the world : the current global position of the cryptocurrency market and future prediction
- Authors: Jayawardhana, Asanga
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: This study was motivated by the breakthrough of cryptocurrencies in 2018. The other main reasons behind the motivation are the total market capitalisation of one trillion-dollar diversification possibilities and the lack of preceding scientific research to identify the portfolio diversification possibilities of cryptocurrencies from many angles. Four empirical studies were conducted to provide a holistic view of cryptocurrency as an investment tool. The first study investigated the portfolio diversification possibilities between cryptocurrencies and traditional financial markets. A quantitative method was employed with Cointegration, ARDL bound testing approach, causality, and co-movement testing. Applying Modern portfolio theory to identify the diversification possibilities between the aforementioned markets enabled the study to highlight how investors can reap the benefits of cryptocurrencies. The second study extended the investigation of the portfolio diversification possibilities of cryptocurrency by including precious metals and cryptocurrencies in the same investment basket. Investors switch from traditional investment assets, such as equity and debt market instruments, to precious metal markets to reap benefits. Therefore, this study investigates how cryptocurrency can be an alternative source of investment to include in an investment portfolio. The daily precious metal and cryptocurrency data from 2017 to 2022 was utilised through an ARDL framework to obtain the Cointegration between cryptocurrency, precious metal and across cryptocurrencies. Modern portfolio theory is used to identify the diversification possibilities in this study with different portfolio diversification strategies. The third study clarified the cryptocurrency stakeholders to identify the global perception of cryptocurrency investments. A qualitative method was employed with sentiment analysis, followed by data extractions from the global databases using machine learning algorithms. The study identified the percentage of stakeholder groups' positive, negative, and neutral perceptions of cryptocurrency. The main obstacles hindering cryptocurrency investment growth are the fear of current scams, lack of definitional issues and the absence of a legal framework in some countries. The fourth study included the findings from the first, second and third studies to develop a cryptocurrency predictive model by factoring in macroeconomic variables. Panel data regression with fixed and dynamic effects was employed to analyse the data from 2017 to 2002. The findings suggest the impact of each macroeconomic variable selected in the study for the cryptocurrency price changes while adding more significance to technological variables. The overall findings provide strong support for the portfolio diversification possibilities of cryptocurrencies. Inclusions of the wide range of investment classes, exploring stakeholder perception and highlighting the macroeconomic variables' influence on the cryptocurrency price prediction generate new insights and valuable comparisons about cryptocurrency markets for academia, crypto issuers, investors, government, policymakers, and fund managers to use as an investment and decision-support tools. Keywords: Cryptocurrency, ARDL, Financial Markets, Cointegration, Causality, Portfolio diversification, Precious Metals, Predictive model.
- Description: Doctor of Philosophy
- Authors: Jayawardhana, Asanga
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: This study was motivated by the breakthrough of cryptocurrencies in 2018. The other main reasons behind the motivation are the total market capitalisation of one trillion-dollar diversification possibilities and the lack of preceding scientific research to identify the portfolio diversification possibilities of cryptocurrencies from many angles. Four empirical studies were conducted to provide a holistic view of cryptocurrency as an investment tool. The first study investigated the portfolio diversification possibilities between cryptocurrencies and traditional financial markets. A quantitative method was employed with Cointegration, ARDL bound testing approach, causality, and co-movement testing. Applying Modern portfolio theory to identify the diversification possibilities between the aforementioned markets enabled the study to highlight how investors can reap the benefits of cryptocurrencies. The second study extended the investigation of the portfolio diversification possibilities of cryptocurrency by including precious metals and cryptocurrencies in the same investment basket. Investors switch from traditional investment assets, such as equity and debt market instruments, to precious metal markets to reap benefits. Therefore, this study investigates how cryptocurrency can be an alternative source of investment to include in an investment portfolio. The daily precious metal and cryptocurrency data from 2017 to 2022 was utilised through an ARDL framework to obtain the Cointegration between cryptocurrency, precious metal and across cryptocurrencies. Modern portfolio theory is used to identify the diversification possibilities in this study with different portfolio diversification strategies. The third study clarified the cryptocurrency stakeholders to identify the global perception of cryptocurrency investments. A qualitative method was employed with sentiment analysis, followed by data extractions from the global databases using machine learning algorithms. The study identified the percentage of stakeholder groups' positive, negative, and neutral perceptions of cryptocurrency. The main obstacles hindering cryptocurrency investment growth are the fear of current scams, lack of definitional issues and the absence of a legal framework in some countries. The fourth study included the findings from the first, second and third studies to develop a cryptocurrency predictive model by factoring in macroeconomic variables. Panel data regression with fixed and dynamic effects was employed to analyse the data from 2017 to 2002. The findings suggest the impact of each macroeconomic variable selected in the study for the cryptocurrency price changes while adding more significance to technological variables. The overall findings provide strong support for the portfolio diversification possibilities of cryptocurrencies. Inclusions of the wide range of investment classes, exploring stakeholder perception and highlighting the macroeconomic variables' influence on the cryptocurrency price prediction generate new insights and valuable comparisons about cryptocurrency markets for academia, crypto issuers, investors, government, policymakers, and fund managers to use as an investment and decision-support tools. Keywords: Cryptocurrency, ARDL, Financial Markets, Cointegration, Causality, Portfolio diversification, Precious Metals, Predictive model.
- Description: Doctor of Philosophy