Deriving value from health 2.0 : A study of social media use among healthcare providers
- Authors: Ukoha, Chukwuma
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Social media applications are increasingly being used by healthcare providers because of the numerous communication, information, and public relations benefits they offer. Despite the growing adoption of social media in healthcare settings, its specific uses and value propositions are not well understood. To ensure continuous improvement, social media performance must be measured. However, little is known about the tools, techniques and yardsticks used to measure social media performance in healthcare settings. This study adopts qualitative research methods to explore healthcare providers’ perspectives on the value of social media in healthcare settings. Australian healthcare providers, from organizations of different sizes and locations, who use social media, were interviewed and the transcripts thematically analysed. The results demonstrate the uses of social media in health care, as well as the steps and techniques in social media measurement. Based on the findings, it is clear that the ability of social media to support various activities in healthcare settings makes it valuable to healthcare providers. Drawing on Bakhtin’s ‘theories’ and Stevens’s theory of measurement, this study theorises on the value of social media and introduces a protocol for measuring social media performance in healthcare settings. As one of the first studies to apply Bakhtinian ideas to consumer health informatics, this study has the potential to pave a new approach to conceptualizing the role of social media, particularly in healthcare settings. By using Stevens’s theory of measurement to explore the yardsticks suitable for social media measurement, this study provides a more nuanced framework for measuring the value of social media in healthcare settings.
- Description: Doctor of Philosophy
- Authors: Ukoha, Chukwuma
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Social media applications are increasingly being used by healthcare providers because of the numerous communication, information, and public relations benefits they offer. Despite the growing adoption of social media in healthcare settings, its specific uses and value propositions are not well understood. To ensure continuous improvement, social media performance must be measured. However, little is known about the tools, techniques and yardsticks used to measure social media performance in healthcare settings. This study adopts qualitative research methods to explore healthcare providers’ perspectives on the value of social media in healthcare settings. Australian healthcare providers, from organizations of different sizes and locations, who use social media, were interviewed and the transcripts thematically analysed. The results demonstrate the uses of social media in health care, as well as the steps and techniques in social media measurement. Based on the findings, it is clear that the ability of social media to support various activities in healthcare settings makes it valuable to healthcare providers. Drawing on Bakhtin’s ‘theories’ and Stevens’s theory of measurement, this study theorises on the value of social media and introduces a protocol for measuring social media performance in healthcare settings. As one of the first studies to apply Bakhtinian ideas to consumer health informatics, this study has the potential to pave a new approach to conceptualizing the role of social media, particularly in healthcare settings. By using Stevens’s theory of measurement to explore the yardsticks suitable for social media measurement, this study provides a more nuanced framework for measuring the value of social media in healthcare settings.
- Description: Doctor of Philosophy
Enhancing service quality and reliability in intelligent traffic system
- Authors: Chowdhury, Abdullahi
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Intelligent Traffic Systems (ITS) can manage on-road traffic efficiently based on real-time traffic conditions, reduce delay at the intersections, and maintain the safety of the road users. However, emergency vehicles still struggle to meet their targeted response time, and an ITS is vulnerable to various types of attacks, including cyberattacks. To address these issues, in this dissertation, we introduce three techniques that enhance the service quality and reliability of an ITS. First, an innovative Emergency Vehicle Priority System (EVPS) is presented to assist an Emergency Vehicle (EV) in attending the incident place faster. Our proposed EVPS determines the proper priority codes of EV based on the type of incidents. After priority code generation, EVPS selects the number of traffic signals needed to be turned green considering the impact on other vehicles gathered in the relevant adjacent cells. Second, for improving reliability, an Intrusion Detection System for traffic signals is proposed for the first time, which leverages traffic and signal characteristics such as the flow rate, vehicle speed, and signal phase time. Shannon’s entropy is used to calculate the uncertainty associated with the likelihood of particular evidence and Dempster-Shafer (DS) decision theory is used to fuse the evidential information. Finally, to improve the reliability of a future ITS, we introduce a model that assesses the trust level of four major On-Board Units (OBU) of a self-driving car along with Global Positioning System (GPS) data and safety messages. Both subjective logic (DS theory) and CertainLogic are used to develop the theoretical underpinning for estimating the trust value of a self-driving car by fusing the trust value of four OBU components, GPS data and safety messages. For evaluation and validation purposes, a popular and widely used traffic simulation package, namely Simulation of Urban Mobility (SUMO), is used to develop the simulation platform using a real map of Melbourne CBD. The relevant historical real data taken from the VicRoads website were used to inject the traffic flow and density in the simulation model. We evaluated the performance of our proposed techniques considering different traffic and signal characteristics such as occupancy rate, flow rate, phase time, and vehicle speed under many realistic scenarios. The simulation result shows the potential efficacy of our proposed techniques for all selected scenarios.
- Description: Doctor of Philosophy
- Authors: Chowdhury, Abdullahi
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Intelligent Traffic Systems (ITS) can manage on-road traffic efficiently based on real-time traffic conditions, reduce delay at the intersections, and maintain the safety of the road users. However, emergency vehicles still struggle to meet their targeted response time, and an ITS is vulnerable to various types of attacks, including cyberattacks. To address these issues, in this dissertation, we introduce three techniques that enhance the service quality and reliability of an ITS. First, an innovative Emergency Vehicle Priority System (EVPS) is presented to assist an Emergency Vehicle (EV) in attending the incident place faster. Our proposed EVPS determines the proper priority codes of EV based on the type of incidents. After priority code generation, EVPS selects the number of traffic signals needed to be turned green considering the impact on other vehicles gathered in the relevant adjacent cells. Second, for improving reliability, an Intrusion Detection System for traffic signals is proposed for the first time, which leverages traffic and signal characteristics such as the flow rate, vehicle speed, and signal phase time. Shannon’s entropy is used to calculate the uncertainty associated with the likelihood of particular evidence and Dempster-Shafer (DS) decision theory is used to fuse the evidential information. Finally, to improve the reliability of a future ITS, we introduce a model that assesses the trust level of four major On-Board Units (OBU) of a self-driving car along with Global Positioning System (GPS) data and safety messages. Both subjective logic (DS theory) and CertainLogic are used to develop the theoretical underpinning for estimating the trust value of a self-driving car by fusing the trust value of four OBU components, GPS data and safety messages. For evaluation and validation purposes, a popular and widely used traffic simulation package, namely Simulation of Urban Mobility (SUMO), is used to develop the simulation platform using a real map of Melbourne CBD. The relevant historical real data taken from the VicRoads website were used to inject the traffic flow and density in the simulation model. We evaluated the performance of our proposed techniques considering different traffic and signal characteristics such as occupancy rate, flow rate, phase time, and vehicle speed under many realistic scenarios. The simulation result shows the potential efficacy of our proposed techniques for all selected scenarios.
- Description: Doctor of Philosophy
Exploring the interior : performing situated responsibility in postcolonising Australia
- Authors: Berger, Karen
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Theatre is a powerful way to investigate the operation of borders due to its live, immediate focus on representation and its potential to test a society’s boundaries. This practice-led research incorporates a performance and an exegesis to ask, ‘How can site-specific theatre that investigates the performance of borders and heterotopia enhance understanding of individual responsibility in postcolonising Australia?’ I take the term postcolonising from Aileen Moreton-Robinson, who argues that the beneficiaries of settler-colonialism (such as myself) must accept responsibility for the past before attempting to address its injustices. As an artist, I am inspired by anthropologist, Deborah Bird Rose, who privileges storytelling as a way of breaking boundaries between the past and present. Michel Foucault coined the term heterotopia (other place) to denote a single real space that juxtaposes several sites that are incompatible. This evokes the contemporary Australian situation of contested sovereignty. As Joanne Tompkins argues, heterotopic theatre can enact such a space in order to raise awareness and work towards societal change. My research demonstrates this both theoretically and practically. My exegesis crosses borders to create a heterotopia by juxtaposing past, present and possible futures, stories and theoretical understandings from diverse sources. The performance created at my home, rather than in a theatre, layers family, local, Australian and international histories to highlight the continuum between the personal and political, and to question current structures of power and knowledge. I use site-specific theatre to diminish the boundaries between performer and audience, creating a visceral heterotopia that facilitates a deeper understanding of personal responsibility in the context of postcolonising Australia.
- Description: Doctor of Philosophy
- Authors: Berger, Karen
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Theatre is a powerful way to investigate the operation of borders due to its live, immediate focus on representation and its potential to test a society’s boundaries. This practice-led research incorporates a performance and an exegesis to ask, ‘How can site-specific theatre that investigates the performance of borders and heterotopia enhance understanding of individual responsibility in postcolonising Australia?’ I take the term postcolonising from Aileen Moreton-Robinson, who argues that the beneficiaries of settler-colonialism (such as myself) must accept responsibility for the past before attempting to address its injustices. As an artist, I am inspired by anthropologist, Deborah Bird Rose, who privileges storytelling as a way of breaking boundaries between the past and present. Michel Foucault coined the term heterotopia (other place) to denote a single real space that juxtaposes several sites that are incompatible. This evokes the contemporary Australian situation of contested sovereignty. As Joanne Tompkins argues, heterotopic theatre can enact such a space in order to raise awareness and work towards societal change. My research demonstrates this both theoretically and practically. My exegesis crosses borders to create a heterotopia by juxtaposing past, present and possible futures, stories and theoretical understandings from diverse sources. The performance created at my home, rather than in a theatre, layers family, local, Australian and international histories to highlight the continuum between the personal and political, and to question current structures of power and knowledge. I use site-specific theatre to diminish the boundaries between performer and audience, creating a visceral heterotopia that facilitates a deeper understanding of personal responsibility in the context of postcolonising Australia.
- Description: Doctor of Philosophy
FEM and XFEM approaches to Investigate the Hydromechanical Interactions within a jointed soft-rock slope
- Authors: Shaghaghi, Tahereh
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: One of the most significant challenges of open-cut mining is to provide stability for the excavated slopes. Unrealistic predictions of the slopes’ behaviour during and after mining operations can lead to the failure of slopes, and this may pose a threat to human lives, the economy, and the environment. By excavating soft rock masses in open-cut mines, pre-existing joints can open and new joints can form behind excavated slopes. This phenomenon is due to the geotechnical character of the materials and stress relief movements of the excavated slopes. The stability of slopes in the rock masses is significantly influenced by the existence of discontinuities such as joints. The water flows in the opened joints can change the pore water pressure distribution in the slopes. The interaction between the joints and the water may impose different loading scenarios on the open-cut mines and put the safety of mining operations at risk. The analysis of slope stability can become more complicated because of the presence of water, discontinuities, and their interaction within the slopes in open-cut mines. This study investigates the hydromechanical interactions in the saturated jointed slopes due to pore water pressure changes. The second-largest open-cut mine in Australia, the Yallourn brown coal open-cut mine located in Victoria, was chosen as the case study for this research. In this study, several coupled pore fluid diffusion and stress-strain analyses are conducted using the extended finite element method (XFEM) in conjunction with the finite element method (FEM). This study firstly examines a joint aperture and pore water pressure changes of the excavated jointed slope due to installing a drainage system and backfilling in front of the slope. Secondly, a series of sensitivity analyses are carried out on the pore water pressure distribution changes to the variation of the permeability magnitude of the material and leakage properties of the joint surfaces. Finally, to control the pore water pressure of the saturated jointed slope, a series of drainage systems is designed. The arrangement and length of the drains are optimised by conducting a series of sensitivity analyses on the leakage properties of the joint and the permeability of the soft rock.
- Description: Doctor of Philosophy
- Authors: Shaghaghi, Tahereh
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: One of the most significant challenges of open-cut mining is to provide stability for the excavated slopes. Unrealistic predictions of the slopes’ behaviour during and after mining operations can lead to the failure of slopes, and this may pose a threat to human lives, the economy, and the environment. By excavating soft rock masses in open-cut mines, pre-existing joints can open and new joints can form behind excavated slopes. This phenomenon is due to the geotechnical character of the materials and stress relief movements of the excavated slopes. The stability of slopes in the rock masses is significantly influenced by the existence of discontinuities such as joints. The water flows in the opened joints can change the pore water pressure distribution in the slopes. The interaction between the joints and the water may impose different loading scenarios on the open-cut mines and put the safety of mining operations at risk. The analysis of slope stability can become more complicated because of the presence of water, discontinuities, and their interaction within the slopes in open-cut mines. This study investigates the hydromechanical interactions in the saturated jointed slopes due to pore water pressure changes. The second-largest open-cut mine in Australia, the Yallourn brown coal open-cut mine located in Victoria, was chosen as the case study for this research. In this study, several coupled pore fluid diffusion and stress-strain analyses are conducted using the extended finite element method (XFEM) in conjunction with the finite element method (FEM). This study firstly examines a joint aperture and pore water pressure changes of the excavated jointed slope due to installing a drainage system and backfilling in front of the slope. Secondly, a series of sensitivity analyses are carried out on the pore water pressure distribution changes to the variation of the permeability magnitude of the material and leakage properties of the joint surfaces. Finally, to control the pore water pressure of the saturated jointed slope, a series of drainage systems is designed. The arrangement and length of the drains are optimised by conducting a series of sensitivity analyses on the leakage properties of the joint and the permeability of the soft rock.
- Description: Doctor of Philosophy
Fraud detection for online banking for scalable and distributed data
- Authors: Haq, Ikram
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Online fraud causes billions of dollars in losses for banks. Therefore, online banking fraud detection is an important field of study. However, there are many challenges in conducting research in fraud detection. One of the constraints is due to unavailability of bank datasets for research or the required characteristics of the attributes of the data are not available. Numeric data usually provides better performance for machine learning algorithms. Most transaction data however have categorical, or nominal features as well. Moreover, some platforms such as Apache Spark only recognizes numeric data. So, there is a need to use techniques e.g. One-hot encoding (OHE) to transform categorical features to numerical features, however OHE has challenges including the sparseness of transformed data and that the distinct values of an attribute are not always known in advance. Efficient feature engineering can improve the algorithm’s performance but usually requires detailed domain knowledge to identify correct features. Techniques like Ripple Down Rules (RDR) are suitable for fraud detection because of their low maintenance and incremental learning features. However, high classification accuracy on mixed datasets, especially for scalable data is challenging. Evaluation of RDR on distributed platforms is also challenging as it is not available on these platforms. The thesis proposes the following solutions to these challenges: • We developed a technique Highly Correlated Rule Based Uniformly Distribution (HCRUD) to generate highly correlated rule-based uniformly-distributed synthetic data. • We developed a technique One-hot Encoded Extended Compact (OHE-EC) to transform categorical features to numeric features by compacting sparse-data even if all distinct values are unknown. • We developed a technique Feature Engineering and Compact Unified Expressions (FECUE) to improve model efficiency through feature engineering where the domain of the data is not known in advance. • A Unified Expression RDR fraud deduction technique (UE-RDR) for Big data has been proposed and evaluated on the Spark platform. Empirical tests were executed on multi-node Hadoop cluster using well-known classifiers on bank data, synthetic bank datasets and publicly available datasets from UCI repository. These evaluations demonstrated substantial improvements in terms of classification accuracy, ruleset compactness and execution speed.
- Description: Doctor of Philosophy
- Authors: Haq, Ikram
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Online fraud causes billions of dollars in losses for banks. Therefore, online banking fraud detection is an important field of study. However, there are many challenges in conducting research in fraud detection. One of the constraints is due to unavailability of bank datasets for research or the required characteristics of the attributes of the data are not available. Numeric data usually provides better performance for machine learning algorithms. Most transaction data however have categorical, or nominal features as well. Moreover, some platforms such as Apache Spark only recognizes numeric data. So, there is a need to use techniques e.g. One-hot encoding (OHE) to transform categorical features to numerical features, however OHE has challenges including the sparseness of transformed data and that the distinct values of an attribute are not always known in advance. Efficient feature engineering can improve the algorithm’s performance but usually requires detailed domain knowledge to identify correct features. Techniques like Ripple Down Rules (RDR) are suitable for fraud detection because of their low maintenance and incremental learning features. However, high classification accuracy on mixed datasets, especially for scalable data is challenging. Evaluation of RDR on distributed platforms is also challenging as it is not available on these platforms. The thesis proposes the following solutions to these challenges: • We developed a technique Highly Correlated Rule Based Uniformly Distribution (HCRUD) to generate highly correlated rule-based uniformly-distributed synthetic data. • We developed a technique One-hot Encoded Extended Compact (OHE-EC) to transform categorical features to numeric features by compacting sparse-data even if all distinct values are unknown. • We developed a technique Feature Engineering and Compact Unified Expressions (FECUE) to improve model efficiency through feature engineering where the domain of the data is not known in advance. • A Unified Expression RDR fraud deduction technique (UE-RDR) for Big data has been proposed and evaluated on the Spark platform. Empirical tests were executed on multi-node Hadoop cluster using well-known classifiers on bank data, synthetic bank datasets and publicly available datasets from UCI repository. These evaluations demonstrated substantial improvements in terms of classification accuracy, ruleset compactness and execution speed.
- Description: Doctor of Philosophy
Grand designs, grim reality : political representation, competition and equity in regional Victoria
- Authors: Tischler, Catherine
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This work brings new understanding to the subtle ways in which the ability of one rural community to change is curtailed by self-reinforcement of an ideology not entirely of their own making. In a political environment where economic returns and population growth appear to be the true indicators of value and success, the struggle of some rural communities to change a long term and seemingly intractable trajectory of decline is well documented. The historical importance of rural communities as a place where food and fibre are grown has been challenged by market forces, climatic conditions and the relative growth of cities and service-based industries over the last three decades. To people in rural areas experiencing population stasis or decline, the situation appears to be a competition that is not being won at a local level. This thesis employs critical ethnography to understand a layered investigation of the ideological paradigms internalised by leaders in this community in a place-based setting to explore how this influences political advocacy and action. The work focusses on the Wimmera Southern Mallee region in Victoria, Australia with a particular emphasis on the city of Horsham as the major regional centre. The purpose of this work is to understand how ideology and behaviours are used to reinforce a system of power that is dominated by prestige leadership. The work also considers how external political and ideological influences may further reinforce on to leaders in the region a set of values and expectations which negatively impact on action and outcomes. The findings of this work have implications for rural community engagement, regional development, place-based initiatives and regional advocacy.
- Description: Doctor of Philosophy
- Authors: Tischler, Catherine
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This work brings new understanding to the subtle ways in which the ability of one rural community to change is curtailed by self-reinforcement of an ideology not entirely of their own making. In a political environment where economic returns and population growth appear to be the true indicators of value and success, the struggle of some rural communities to change a long term and seemingly intractable trajectory of decline is well documented. The historical importance of rural communities as a place where food and fibre are grown has been challenged by market forces, climatic conditions and the relative growth of cities and service-based industries over the last three decades. To people in rural areas experiencing population stasis or decline, the situation appears to be a competition that is not being won at a local level. This thesis employs critical ethnography to understand a layered investigation of the ideological paradigms internalised by leaders in this community in a place-based setting to explore how this influences political advocacy and action. The work focusses on the Wimmera Southern Mallee region in Victoria, Australia with a particular emphasis on the city of Horsham as the major regional centre. The purpose of this work is to understand how ideology and behaviours are used to reinforce a system of power that is dominated by prestige leadership. The work also considers how external political and ideological influences may further reinforce on to leaders in the region a set of values and expectations which negatively impact on action and outcomes. The findings of this work have implications for rural community engagement, regional development, place-based initiatives and regional advocacy.
- Description: Doctor of Philosophy
Herbicide application strategies for wild radish management in Imidazolinone tolerant faba bean
- Authors: Welgama, Amali
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: The extensive and continual use of herbicides in cropping situations has inevitably led to the phenomenon of "herbicide-resistance" in weeds and this has become one of the most challenging issues in modern agriculture. Herbicide-tolerant crops (HTC) were introduced to diversify weed management practices, but the lack of integrated weed management strategies, along with the continuous use of the same herbicide mode of action (MOA) demanded by the HTC has continued to impose selection pressure on weeds to evolve with herbicide resistance. Consequently, this thesis has been focused on the introduction of herbicide MOA combinations into HTC systems in an attempt to reduce the rate of herbicide resistance evolution in weeds. Raphanus raphanistrum is the number one broadleaf weed in Australia, and for this case study, the newly released ALS-inhibiting imidazolinone tolerant faba bean cultivar PBA Bendoc with its conventional cultivar, PBA Samira, were selected as the study species. ALS-inhibiting (imazamox + imazapyr and imazethapyr) and PSII-inhibiting (metribuzin) herbicides were used as the two herbicide MOAs. The herbicide sensitivity of R. raphanistrum was initially evaluated at different growth stages, in glasshouse studies using herbicide-resistant and susceptible biotypes to ALS-inhibiting herbicides. The highest susceptibility was observed at the earliest growth stage regardless of the biotype and Imazamox + imazapyr proved to be more effective in controlling both biotypes compared to imazethapyr. The same two herbicides were tested on faba bean cultivars at different growth stages to assess crop tolerance and identify the herbicide application window. The field trials conducted in 2018 and 2019 showed increased ALS-inhibiting herbicide tolerance in PBA Bendoc compared to PBA Samira even at the most advanced growth stage. Both faba bean cultivars were then evaluated for their tolerance to metribuzin in-crop application at different herbicide rates. Both cultivars responded similarly, showing progressive herbicide damage with increasing application rates. However, the reduced pod number, even at the lowest rate used, flagged the possible yield penalties that may result in using in-crop metribuzin applications. It is thus suggested that metribuzin must be used post sowing pre-emergent (PSPE) respecting the label recommendations. The potential herbicide combinations were then tested on herbicide-resistant R. raphanistrum and PBA Bendoc to evaluate their efficacies. Metribuzin was initially used as PSPE in all combinations, and was to be followed by imazamox + imazapyr applications at the same growth stages of the weed and the crop as in previous experiments. However, 100% control of R. raphanistrum was achieved using metribuzin alone, and thus no second herbicide was required. All the assessed herbicide combinations were tolerated by PBA Bendoc, proving the suitability of these herbicide combinations for incorporation into the PBA Bendoc cropping system. These results led to two potential herbicide combination strategies: (i) herbicide rotations, with metribuzin as PSPE in one year along with another potential herbicide MOA in the following year, (ii) herbicide sequential application, with metribuzin applied at PSPE and imazamox + imazapyr applied at the 2-4 leaf stage if R. raphanistrum plants survived the metribuzin treatment. A seed germination study was conducted under different temperature/photoperiods, pH levels, osmotic potentials, salinity and burial depths to identify the optimal germination conditions for R. raphanistrum. The optimum germination conditions for both herbicide-resistant and susceptible biotypes of R. raphanistrum were found to be 25ºC/15ºC temperature range under 24 hours complete dark. However, the significant interaction between photoperiod and temperature indicated that the seed germination under higher temperatures is less favoured by 24 hours dark conditions regardless of the biotype. An increased moisture stress tolerance in herbicide-resistant seeds was observed, whilst both biotypes reacted similarly to different pH levels and burial depths. In summary, this thesis has elucidated the effectiveness of two herbicide MOAs in controlling R. raphanistrum while addressing the crop tolerance to these herbicide MOA combinations. These findings will help in setting up stewardship guidelines to be used with the PBA Bendoc faba bean cultivar to mitigate the misuse of herbicides, thus ensuring their sustainable application. In addition, the demonstration of differential seed germination requirements of resistant and susceptible R. raphanistrum seeds has provided further information to help with its systematic management. Overall, this study can be used as a case study to investigate herbicide options that can be used in different HT crop cultivars to control a range of weed species.
- Description: Doctor of Philosophy
- Authors: Welgama, Amali
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: The extensive and continual use of herbicides in cropping situations has inevitably led to the phenomenon of "herbicide-resistance" in weeds and this has become one of the most challenging issues in modern agriculture. Herbicide-tolerant crops (HTC) were introduced to diversify weed management practices, but the lack of integrated weed management strategies, along with the continuous use of the same herbicide mode of action (MOA) demanded by the HTC has continued to impose selection pressure on weeds to evolve with herbicide resistance. Consequently, this thesis has been focused on the introduction of herbicide MOA combinations into HTC systems in an attempt to reduce the rate of herbicide resistance evolution in weeds. Raphanus raphanistrum is the number one broadleaf weed in Australia, and for this case study, the newly released ALS-inhibiting imidazolinone tolerant faba bean cultivar PBA Bendoc with its conventional cultivar, PBA Samira, were selected as the study species. ALS-inhibiting (imazamox + imazapyr and imazethapyr) and PSII-inhibiting (metribuzin) herbicides were used as the two herbicide MOAs. The herbicide sensitivity of R. raphanistrum was initially evaluated at different growth stages, in glasshouse studies using herbicide-resistant and susceptible biotypes to ALS-inhibiting herbicides. The highest susceptibility was observed at the earliest growth stage regardless of the biotype and Imazamox + imazapyr proved to be more effective in controlling both biotypes compared to imazethapyr. The same two herbicides were tested on faba bean cultivars at different growth stages to assess crop tolerance and identify the herbicide application window. The field trials conducted in 2018 and 2019 showed increased ALS-inhibiting herbicide tolerance in PBA Bendoc compared to PBA Samira even at the most advanced growth stage. Both faba bean cultivars were then evaluated for their tolerance to metribuzin in-crop application at different herbicide rates. Both cultivars responded similarly, showing progressive herbicide damage with increasing application rates. However, the reduced pod number, even at the lowest rate used, flagged the possible yield penalties that may result in using in-crop metribuzin applications. It is thus suggested that metribuzin must be used post sowing pre-emergent (PSPE) respecting the label recommendations. The potential herbicide combinations were then tested on herbicide-resistant R. raphanistrum and PBA Bendoc to evaluate their efficacies. Metribuzin was initially used as PSPE in all combinations, and was to be followed by imazamox + imazapyr applications at the same growth stages of the weed and the crop as in previous experiments. However, 100% control of R. raphanistrum was achieved using metribuzin alone, and thus no second herbicide was required. All the assessed herbicide combinations were tolerated by PBA Bendoc, proving the suitability of these herbicide combinations for incorporation into the PBA Bendoc cropping system. These results led to two potential herbicide combination strategies: (i) herbicide rotations, with metribuzin as PSPE in one year along with another potential herbicide MOA in the following year, (ii) herbicide sequential application, with metribuzin applied at PSPE and imazamox + imazapyr applied at the 2-4 leaf stage if R. raphanistrum plants survived the metribuzin treatment. A seed germination study was conducted under different temperature/photoperiods, pH levels, osmotic potentials, salinity and burial depths to identify the optimal germination conditions for R. raphanistrum. The optimum germination conditions for both herbicide-resistant and susceptible biotypes of R. raphanistrum were found to be 25ºC/15ºC temperature range under 24 hours complete dark. However, the significant interaction between photoperiod and temperature indicated that the seed germination under higher temperatures is less favoured by 24 hours dark conditions regardless of the biotype. An increased moisture stress tolerance in herbicide-resistant seeds was observed, whilst both biotypes reacted similarly to different pH levels and burial depths. In summary, this thesis has elucidated the effectiveness of two herbicide MOAs in controlling R. raphanistrum while addressing the crop tolerance to these herbicide MOA combinations. These findings will help in setting up stewardship guidelines to be used with the PBA Bendoc faba bean cultivar to mitigate the misuse of herbicides, thus ensuring their sustainable application. In addition, the demonstration of differential seed germination requirements of resistant and susceptible R. raphanistrum seeds has provided further information to help with its systematic management. Overall, this study can be used as a case study to investigate herbicide options that can be used in different HT crop cultivars to control a range of weed species.
- Description: Doctor of Philosophy
Imbalanced data classification and its application in cyber security
- Authors: Moniruzzaman, Md
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Cyber security, also known as information technology security or simply as information security, aims to protect government organizations, companies and individuals by defending their computers, servers, electronic systems, networks, and data from malicious attacks. With the advancement of client-side on the fly web content generation techniques, it becomes easier for attackers to modify the content of a website dynamically and gain access to valuable information. The impact of cybercrime to the global economy is now more than ever, and it is growing day by day. Among various types of cybercrimes, financial attacks are widely spread and the financial sector is among most targeted. Both corporations and individuals are losing a huge amount of money each year. The majority portion of financial attacks is carried out by banking malware and web-based attacks. The end users are not always skilled enough to differentiate between injected content and actual contents of a webpage. Designing a real-time security system for ensuring a safe browsing experience is a challenging task. Some of the existing solutions are designed for client side and all the users have to install it in their system, which is very difficult to implement. In addition, various platforms and tools are used by organizations and individuals, therefore, different solutions are needed to be designed. The existing server-side solution often focuses on sanitizing and filtering the inputs. It will fail to detect obfuscated and hidden scripts. This is a realtime security system and any significant delay will hamper user experience. Therefore, finding the most optimized and efficient solution is very important. To ensure an easy installation and integration capabilities of any solution with the existing system is also a critical factor to consider. If the solution is efficient but difficult to integrate, then it may not be a feasible solution for practical use. Unsupervised and supervised data classification techniques have been widely applied to design algorithms for solving cyber security problems. The performance of these algorithms varies depending on types of cyber security problems and size of datasets. To date, existing algorithms do not achieve high accuracy in detecting malware activities. Datasets in cyber security and, especially those from financial sectors, are predominantly imbalanced datasets as the number of malware activities is significantly less than the number of normal activities. This means that classifiers for imbalanced datasets can be used to develop supervised data classification algorithms to detect malware activities. Development of classifiers for imbalanced data sets has been subject of research over the last decade. Most of these classifiers are based on oversampling and undersampling techniques and are not efficient in many situations as such techniques are applied globally. In this thesis, we develop two new algorithms for solving supervised data classification problems in imbalanced datasets and then apply them to solve malware detection problems. The first algorithm is designed using the piecewise linear classifiers by formulating this problem as an optimization problem and by applying the penalty function method. More specifically, we add more penalty to the objective function for misclassified points from minority classes. The second method is based on the combination of the supervised and unsupervised (clustering) algorithms. Such an approach allows one to identify areas in the input space where minority classes are located and to apply local oversampling or undersampling. This approach leads to the design of more efficient and accurate classifiers. The proposed algorithms are tested using real-world datasets. Results clearly demonstrate superiority of newly introduced algorithms. Then we apply these algorithms to design classifiers to detect malwares.
- Description: Doctor of Philosophy
- Authors: Moniruzzaman, Md
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Cyber security, also known as information technology security or simply as information security, aims to protect government organizations, companies and individuals by defending their computers, servers, electronic systems, networks, and data from malicious attacks. With the advancement of client-side on the fly web content generation techniques, it becomes easier for attackers to modify the content of a website dynamically and gain access to valuable information. The impact of cybercrime to the global economy is now more than ever, and it is growing day by day. Among various types of cybercrimes, financial attacks are widely spread and the financial sector is among most targeted. Both corporations and individuals are losing a huge amount of money each year. The majority portion of financial attacks is carried out by banking malware and web-based attacks. The end users are not always skilled enough to differentiate between injected content and actual contents of a webpage. Designing a real-time security system for ensuring a safe browsing experience is a challenging task. Some of the existing solutions are designed for client side and all the users have to install it in their system, which is very difficult to implement. In addition, various platforms and tools are used by organizations and individuals, therefore, different solutions are needed to be designed. The existing server-side solution often focuses on sanitizing and filtering the inputs. It will fail to detect obfuscated and hidden scripts. This is a realtime security system and any significant delay will hamper user experience. Therefore, finding the most optimized and efficient solution is very important. To ensure an easy installation and integration capabilities of any solution with the existing system is also a critical factor to consider. If the solution is efficient but difficult to integrate, then it may not be a feasible solution for practical use. Unsupervised and supervised data classification techniques have been widely applied to design algorithms for solving cyber security problems. The performance of these algorithms varies depending on types of cyber security problems and size of datasets. To date, existing algorithms do not achieve high accuracy in detecting malware activities. Datasets in cyber security and, especially those from financial sectors, are predominantly imbalanced datasets as the number of malware activities is significantly less than the number of normal activities. This means that classifiers for imbalanced datasets can be used to develop supervised data classification algorithms to detect malware activities. Development of classifiers for imbalanced data sets has been subject of research over the last decade. Most of these classifiers are based on oversampling and undersampling techniques and are not efficient in many situations as such techniques are applied globally. In this thesis, we develop two new algorithms for solving supervised data classification problems in imbalanced datasets and then apply them to solve malware detection problems. The first algorithm is designed using the piecewise linear classifiers by formulating this problem as an optimization problem and by applying the penalty function method. More specifically, we add more penalty to the objective function for misclassified points from minority classes. The second method is based on the combination of the supervised and unsupervised (clustering) algorithms. Such an approach allows one to identify areas in the input space where minority classes are located and to apply local oversampling or undersampling. This approach leads to the design of more efficient and accurate classifiers. The proposed algorithms are tested using real-world datasets. Results clearly demonstrate superiority of newly introduced algorithms. Then we apply these algorithms to design classifiers to detect malwares.
- Description: Doctor of Philosophy
Impact of workplace guanxi on knowledge sharing and innovative work behaviour : a study of academic staff of Chinese local universities in Guangdong Province
- Liu, Li
- Authors: Liu, Li
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis aims to investigate the impact of workplace guanxi upon knowledge sharing and innovative work behaviour. Knowledge sharing and innovative work behaviour are two behavioural variables which have been linked to various positive individual and organisational outcomes. Against the changing landscape of Chinese higher education, the two behaviours are particularly important for the success of Chinese academic staff and the local universities where they work. Extant literature has demonstrated that workplace interpersonal relationships such as leader-member exchange and team-member exchange are positively associated with individual’s work behaviours, such as knowledge sharing and innovative work behaviour. However, there is a scant literature on the impact of workplace guanxi upon the two workplace behaviours. Using conservation of resource theory and social exchange theory, this research conceptualised a structural model to study the impact of workplace guanxi upon knowledge sharing and innovative work behaviour. A positivist approach with cross-sectional design and structural equation modelling was adopted to test the conceptualised model. Data were extracted from 479 academic staff of seven local universities in Guangdong Province of China, through selfreport questionnaire. A positive relationship was found between coworker guanxi and knowledge sharing. In contrast, no relationship was found between supervisor-subordinate guanxi and knowledge sharing. The relationship between coworker guanxi and knowledge sharing was fully mediated by teammember exchange and job satisfaction. In terms of innovative work behaviour, both supervisorsubordinate guanxi and coworker guanxi displayed a positive relationship with innovative work behaviour. Coworker guanxi showed a stronger relationship with innovative work behaviour than supervisor-subordinate guanxi did. The relationship between supervisorsubordinate guanxi and innovative work behaviour was direct. The relationship between coworker guanxi and innovative work behaviour was indirect, with full mediation of teammember exchange, job satisfaction and knowledge sharing. This thesis contributes to the literature on explaining the role of workplace guanxi, including supervisor-subordinate guanxi and coworker guanxi on knowledge sharing and innovative work behaviour. The study also demonstrates to higher education institute managers that the cultivation of academic staff’s workplace guanxi, and particularly their guanxi with peer academics, promotes academic staff’s displays of knowledge sharing and innovative work behaviour which are beneficial at both individual and organisational levels within the higher education context.
- Description: Doctor of Philosophy
- Authors: Liu, Li
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis aims to investigate the impact of workplace guanxi upon knowledge sharing and innovative work behaviour. Knowledge sharing and innovative work behaviour are two behavioural variables which have been linked to various positive individual and organisational outcomes. Against the changing landscape of Chinese higher education, the two behaviours are particularly important for the success of Chinese academic staff and the local universities where they work. Extant literature has demonstrated that workplace interpersonal relationships such as leader-member exchange and team-member exchange are positively associated with individual’s work behaviours, such as knowledge sharing and innovative work behaviour. However, there is a scant literature on the impact of workplace guanxi upon the two workplace behaviours. Using conservation of resource theory and social exchange theory, this research conceptualised a structural model to study the impact of workplace guanxi upon knowledge sharing and innovative work behaviour. A positivist approach with cross-sectional design and structural equation modelling was adopted to test the conceptualised model. Data were extracted from 479 academic staff of seven local universities in Guangdong Province of China, through selfreport questionnaire. A positive relationship was found between coworker guanxi and knowledge sharing. In contrast, no relationship was found between supervisor-subordinate guanxi and knowledge sharing. The relationship between coworker guanxi and knowledge sharing was fully mediated by teammember exchange and job satisfaction. In terms of innovative work behaviour, both supervisorsubordinate guanxi and coworker guanxi displayed a positive relationship with innovative work behaviour. Coworker guanxi showed a stronger relationship with innovative work behaviour than supervisor-subordinate guanxi did. The relationship between supervisorsubordinate guanxi and innovative work behaviour was direct. The relationship between coworker guanxi and innovative work behaviour was indirect, with full mediation of teammember exchange, job satisfaction and knowledge sharing. This thesis contributes to the literature on explaining the role of workplace guanxi, including supervisor-subordinate guanxi and coworker guanxi on knowledge sharing and innovative work behaviour. The study also demonstrates to higher education institute managers that the cultivation of academic staff’s workplace guanxi, and particularly their guanxi with peer academics, promotes academic staff’s displays of knowledge sharing and innovative work behaviour which are beneficial at both individual and organisational levels within the higher education context.
- Description: Doctor of Philosophy
Implementing inclusion : classroom journeys
- Authors: Elvey, Moya
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This study interrogates the professional experiences, attitudes and pedagogical choices of eight classroom teachers in regular schools and inquires into their impact on the development of inclusive teaching practices. Approached from the perspective of an experienced teaching practitioner, the study responds to the call for an increased focus on the role of classroom teachers in implementing inclusion in schools. The study is underpinned by a theoretical stance that promotes the value of inclusive education through a human rights, access and equity framework. It advocates for the importance of overcoming the discriminatory practices that marginalise some students. Consistent with a qualitative, ethnographic methodology, observations and interviews with practicing teachers provide insights into the factors that encourage, and sometimes discourage, the enactment of inclusive pedagogies. The literature on inclusive education provides guidance throughout the data collection and analysis process. This includes frameworks designed by other researchers that outline and define inclusive teaching strategies. The study exposes the pivotal role that ongoing teacher professional learning, along with strategic guidance and support from colleagues and school leaders, plays in enhancing teacher capacity and positive attitudes towards student diversity. It also uncovers evidence that when medical reports and pressure from ‘others’ such as health professionals, encourage teachers to focus on student ‘deficits’ and ‘problems’, they are more likely to seek out and adopt strategies that marginalise and set some students apart from their peers. A fundamental finding of this study is that when teachers and their school leaders focus on developing understanding about ‘effective’ pedagogies - on quality education for all - responsive, inclusive, student-centred teaching approaches often become embedded in their everyday classroom practice.
- Description: PhD
- Authors: Elvey, Moya
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This study interrogates the professional experiences, attitudes and pedagogical choices of eight classroom teachers in regular schools and inquires into their impact on the development of inclusive teaching practices. Approached from the perspective of an experienced teaching practitioner, the study responds to the call for an increased focus on the role of classroom teachers in implementing inclusion in schools. The study is underpinned by a theoretical stance that promotes the value of inclusive education through a human rights, access and equity framework. It advocates for the importance of overcoming the discriminatory practices that marginalise some students. Consistent with a qualitative, ethnographic methodology, observations and interviews with practicing teachers provide insights into the factors that encourage, and sometimes discourage, the enactment of inclusive pedagogies. The literature on inclusive education provides guidance throughout the data collection and analysis process. This includes frameworks designed by other researchers that outline and define inclusive teaching strategies. The study exposes the pivotal role that ongoing teacher professional learning, along with strategic guidance and support from colleagues and school leaders, plays in enhancing teacher capacity and positive attitudes towards student diversity. It also uncovers evidence that when medical reports and pressure from ‘others’ such as health professionals, encourage teachers to focus on student ‘deficits’ and ‘problems’, they are more likely to seek out and adopt strategies that marginalise and set some students apart from their peers. A fundamental finding of this study is that when teachers and their school leaders focus on developing understanding about ‘effective’ pedagogies - on quality education for all - responsive, inclusive, student-centred teaching approaches often become embedded in their everyday classroom practice.
- Description: PhD
Intelligent zero-day intrusion detection framework for internet of things
- Authors: Khraisat, Ansam
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Zero-day intrusion detection system faces serious challenges as hundreds of thousands of new instances of malware are being created every day to cause harm or damage to the computer system. Cyber-attacks are becoming more sophisticated, leading to challenges in intrusion detection. There are many Intrusion Detection Systems (IDSs), which are proposed to identify abnormal activities, but most of these IDSs produce a large number of false positives and low detection accuracy. Hence, a significant quantity of false positives could generate a high-level of alerts in a short period of time as the normal activities are classified as intrusion activities. This thesis proposes a novel framework of hybrid intrusion detection system that integrates the Signature Intrusion Detection System (SIDS) with the Anomaly Intrusion Detection System (AIDS) to detect zero-day attacks with high accuracy. SIDS has been used to identify previously known intrusions, and AIDS has been applied to detect unknown zero-day intrusions. The goal of this research is to combine the strengths of each technique toward the development of a hybrid framework for the efficient intrusion detection system. A number of performance measures including accuracy, F-measure and area under ROC curve have been used to evaluate the efficacy of our proposed models and to compare and contrast with existing approaches. Extensive simulation results conducted in this thesis show that the proposed framework is capable of yielding excellent detection performance when tested with a number of widely used benchmark datasets in the intrusion detection system domain. Experiments show that the proposed hybrid IDS provides higher detection rate and lower false-positive rate in detecting intrusions as compared to the SIDS and AIDS techniques individually.
- Description: Doctor of Philosophy
- Authors: Khraisat, Ansam
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Zero-day intrusion detection system faces serious challenges as hundreds of thousands of new instances of malware are being created every day to cause harm or damage to the computer system. Cyber-attacks are becoming more sophisticated, leading to challenges in intrusion detection. There are many Intrusion Detection Systems (IDSs), which are proposed to identify abnormal activities, but most of these IDSs produce a large number of false positives and low detection accuracy. Hence, a significant quantity of false positives could generate a high-level of alerts in a short period of time as the normal activities are classified as intrusion activities. This thesis proposes a novel framework of hybrid intrusion detection system that integrates the Signature Intrusion Detection System (SIDS) with the Anomaly Intrusion Detection System (AIDS) to detect zero-day attacks with high accuracy. SIDS has been used to identify previously known intrusions, and AIDS has been applied to detect unknown zero-day intrusions. The goal of this research is to combine the strengths of each technique toward the development of a hybrid framework for the efficient intrusion detection system. A number of performance measures including accuracy, F-measure and area under ROC curve have been used to evaluate the efficacy of our proposed models and to compare and contrast with existing approaches. Extensive simulation results conducted in this thesis show that the proposed framework is capable of yielding excellent detection performance when tested with a number of widely used benchmark datasets in the intrusion detection system domain. Experiments show that the proposed hybrid IDS provides higher detection rate and lower false-positive rate in detecting intrusions as compared to the SIDS and AIDS techniques individually.
- Description: Doctor of Philosophy
Interactions between a gall–inducing wasp Trichilogaster acaciaelongifoliae (Hymenoptera: Pteromalidae) and its host plant Acacia longifolia (Fabaceae)
- Authors: Islam, Md Rashedul
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Sallow Wattle (Acacia longifolia subsp. longifolia) is a native Australian shrub which is an invasive weed in some parts of Australia, and internationally. A gall-forming wasp (Trichilogaster acaciaelongifoliae), also native to Australia, causes abnormal growth of tissues (galls) in Sallow Wattle. This wasp is used outside of Australia to control invasive populations of this plant species. However, in Australia, the wasp is not effective in managing the spread of Sallow Wattle. This study investigates various aspects of the relationship between the wasp and its host plant in Australian ecosystems to better understand the physiological and ecological processes involved. The study shows that this wasp is host-specific on Sallow Wattle. The feeding action of the larval wasps increase secondary plant compounds in gall tissue, which may assist the plant to defend itself chemically against other insects and microorganisms. The growth of the galls redirects resources which are otherwise used by the plant for growth and reproduction. A second insect species was found within the galls and was identified as Megastigmus sp. This second species is likely to be a parasitoid, killing the larvae of the gall-former and occupying the gall. The presence of Megastigmus sp. in Australian ecosystems may be a key factor affecting the ability of T. acaciaelongifoliae to control Sallow Wattle in its native range. The structure of galls formed by each type of gall-inducing insects is unique and the process of gall induction also varies across species. The present study has specifically examined the initiation and development of galls formed by T. acaciaelongifoliae on A. l. longifolia. Unlike other hymenopteran groups, which induce galls during oviposition, T. acaciaelongifoliae appears to form galls on A. l. longifolia via the larval feeding process. Three major stages of gall development were identified and described: induction of gall, growth and maturation of gall, and shrinking and desiccation of gall. These findings have significantly extended our current knowledge of gall induction and development by the hymenopteran group of insects. Total antioxidant capacity (TAC), total phenol (TP), and total anthocyanin (TA) were measured in galls formed by T. acaciaelongifoliae at different growth stages of galls and in other plant tissue samples of A. l. longifolia to understand the effect of gall formation on plant phytochemistry. The results indicated differences in the amounts of phytochemicals in tissue samples from galls of different growth stages of galls and between gall tissue samples and other plant samples of A. l. longifolia. The highest amount of total antioxidant capacity, total phenols and total anthocyanin were recorded in samples of early stages galls, whereas the minimum amounts of phytochemicals were in stems of A. l. longifolia. Amounts of antioxidant capacity, phenols and anthocyanin gradually declined as galls developed and larvae became less active in their feeding activity prior to pupation. It is assumed that the active feeding action of the larvae results in increased amounts of these chemicals in the early growth stages of the galls. The effect of galls formed by the wasp, T. acaciaelongifoliae on the growth and reproduction of A. l. longifolia was investigated in the native home range of both species, where the plant is invasive. Differences in the average number of phyllodes per sub-branch were found between galled and ungalled plants. Galls were also shown to affect the growth rate of branches. The number of galls correlated positively with twig mortality; and negatively with the number of seedpods per sub-branch. While galls formed by T. acaciaelongifoliae have impacts on the growth and reproduction of A. l. longifolia plants, the plant continues to invade Australian ecosystems. An experiment was conducted to investigate the host plant preference of T. acaciaelongifoliae. Ten different native host plant species (co-occurring with A. l. longifolia in the study locations) were tested in two set of experiments; a ‘free choice test’ and ‘no choice test’. The results showed that T. acaciaelongifoliae is highly host-specific on A. l. longifolia plants. Thus, it was concluded that the presence of other plant species does not explain the continued invasiveness of A. l. longifolia in Australia. A second insect species was found in the galls developed by T. acaciaelongifoliae on A. l. longifolia. The insect species has been identified as another hymenopteran from the genus Megastigmus. Since no T. acaciaelongifoliae emerged from the galls occupied by Megastigmus sp, it is proposed that Megastigmus sp. may feed upon T. acaciaelongifoliae larvae and kill them inside the galls. This might be a key factor affecting the performance of the wasp, T. acaciaelongifoliae in controlling A. l. longifolia in its native distribution. Parasitism rates of Megastigmus sp. should be investigated in future experiments.
- Description: Doctor of Philosophy
- Authors: Islam, Md Rashedul
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Sallow Wattle (Acacia longifolia subsp. longifolia) is a native Australian shrub which is an invasive weed in some parts of Australia, and internationally. A gall-forming wasp (Trichilogaster acaciaelongifoliae), also native to Australia, causes abnormal growth of tissues (galls) in Sallow Wattle. This wasp is used outside of Australia to control invasive populations of this plant species. However, in Australia, the wasp is not effective in managing the spread of Sallow Wattle. This study investigates various aspects of the relationship between the wasp and its host plant in Australian ecosystems to better understand the physiological and ecological processes involved. The study shows that this wasp is host-specific on Sallow Wattle. The feeding action of the larval wasps increase secondary plant compounds in gall tissue, which may assist the plant to defend itself chemically against other insects and microorganisms. The growth of the galls redirects resources which are otherwise used by the plant for growth and reproduction. A second insect species was found within the galls and was identified as Megastigmus sp. This second species is likely to be a parasitoid, killing the larvae of the gall-former and occupying the gall. The presence of Megastigmus sp. in Australian ecosystems may be a key factor affecting the ability of T. acaciaelongifoliae to control Sallow Wattle in its native range. The structure of galls formed by each type of gall-inducing insects is unique and the process of gall induction also varies across species. The present study has specifically examined the initiation and development of galls formed by T. acaciaelongifoliae on A. l. longifolia. Unlike other hymenopteran groups, which induce galls during oviposition, T. acaciaelongifoliae appears to form galls on A. l. longifolia via the larval feeding process. Three major stages of gall development were identified and described: induction of gall, growth and maturation of gall, and shrinking and desiccation of gall. These findings have significantly extended our current knowledge of gall induction and development by the hymenopteran group of insects. Total antioxidant capacity (TAC), total phenol (TP), and total anthocyanin (TA) were measured in galls formed by T. acaciaelongifoliae at different growth stages of galls and in other plant tissue samples of A. l. longifolia to understand the effect of gall formation on plant phytochemistry. The results indicated differences in the amounts of phytochemicals in tissue samples from galls of different growth stages of galls and between gall tissue samples and other plant samples of A. l. longifolia. The highest amount of total antioxidant capacity, total phenols and total anthocyanin were recorded in samples of early stages galls, whereas the minimum amounts of phytochemicals were in stems of A. l. longifolia. Amounts of antioxidant capacity, phenols and anthocyanin gradually declined as galls developed and larvae became less active in their feeding activity prior to pupation. It is assumed that the active feeding action of the larvae results in increased amounts of these chemicals in the early growth stages of the galls. The effect of galls formed by the wasp, T. acaciaelongifoliae on the growth and reproduction of A. l. longifolia was investigated in the native home range of both species, where the plant is invasive. Differences in the average number of phyllodes per sub-branch were found between galled and ungalled plants. Galls were also shown to affect the growth rate of branches. The number of galls correlated positively with twig mortality; and negatively with the number of seedpods per sub-branch. While galls formed by T. acaciaelongifoliae have impacts on the growth and reproduction of A. l. longifolia plants, the plant continues to invade Australian ecosystems. An experiment was conducted to investigate the host plant preference of T. acaciaelongifoliae. Ten different native host plant species (co-occurring with A. l. longifolia in the study locations) were tested in two set of experiments; a ‘free choice test’ and ‘no choice test’. The results showed that T. acaciaelongifoliae is highly host-specific on A. l. longifolia plants. Thus, it was concluded that the presence of other plant species does not explain the continued invasiveness of A. l. longifolia in Australia. A second insect species was found in the galls developed by T. acaciaelongifoliae on A. l. longifolia. The insect species has been identified as another hymenopteran from the genus Megastigmus. Since no T. acaciaelongifoliae emerged from the galls occupied by Megastigmus sp, it is proposed that Megastigmus sp. may feed upon T. acaciaelongifoliae larvae and kill them inside the galls. This might be a key factor affecting the performance of the wasp, T. acaciaelongifoliae in controlling A. l. longifolia in its native distribution. Parasitism rates of Megastigmus sp. should be investigated in future experiments.
- Description: Doctor of Philosophy
Internationalisation of higher education curriculum : a case study in Vietnam
- Authors: Luong, Thi Phuong
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis investigated how the process of internationalisation of the curriculum (IoC) was perceived as taking place at a non-western university, namely Foreign Trade University (FTU) in Vietnam, through the development and offering of a number of jointly run programs, labelled Foreign Undergraduate Programs (FUPs). Two specific programs were examined, both of which were developed in partnership with two western universities – Colorado State University (FTU-CSU program) and London Metropolitan University (FTU-LMET program). These programs provide a range of opportunities for Vietnamese university students to experience an education that aims to reflect an international and therefore ‘broader’ context. The relationship between globalisation and internationalisation is explored and linked with the development of curriculum in higher education and internationalisation trends and strategies. Internationalisation of the curriculum, which is one of the internationalisation strategies employed by educational institutions, is investigated in terms of its interrelationship with student learning, the disciplines and academics. Engeström’s (2001) third generation Activity Theory was used as the theoretical lens for analysis of the data, which was collected via a mainly qualitative case study. Two cohorts of participants provided data through 24 interviews (seven including a joint one with program leaders/course coordinators, and 17 with academics) and 34 surveys completed by academics. The interviews/survey investigated participants’ perceptions about internationalisation and particularly IoC in relation to the two programs. Part of the significance of this study lies in the use of a number of conceptual and theoretical frameworks to extend the current body of literature beyond the main context of western higher education. An innovation in this study was the evaluation of the level of curriculum internationalisation at FTU, which was conducted using the model of curriculum internationalisation proposed by Huang (2017). Findings suggested that program managers and course coordinators worked collaboratively with their western partners to provide programs that they perceived as worthwhile in meeting the needs of the institution and the Vietnamese government agenda for internationalisation. However, academics were not generally well informed about the broader goals relating to IoC and found it challenging to accommodate the expectations with limited resources and lack of appropriate training.
- Description: Doctor of Philosophy
- Authors: Luong, Thi Phuong
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis investigated how the process of internationalisation of the curriculum (IoC) was perceived as taking place at a non-western university, namely Foreign Trade University (FTU) in Vietnam, through the development and offering of a number of jointly run programs, labelled Foreign Undergraduate Programs (FUPs). Two specific programs were examined, both of which were developed in partnership with two western universities – Colorado State University (FTU-CSU program) and London Metropolitan University (FTU-LMET program). These programs provide a range of opportunities for Vietnamese university students to experience an education that aims to reflect an international and therefore ‘broader’ context. The relationship between globalisation and internationalisation is explored and linked with the development of curriculum in higher education and internationalisation trends and strategies. Internationalisation of the curriculum, which is one of the internationalisation strategies employed by educational institutions, is investigated in terms of its interrelationship with student learning, the disciplines and academics. Engeström’s (2001) third generation Activity Theory was used as the theoretical lens for analysis of the data, which was collected via a mainly qualitative case study. Two cohorts of participants provided data through 24 interviews (seven including a joint one with program leaders/course coordinators, and 17 with academics) and 34 surveys completed by academics. The interviews/survey investigated participants’ perceptions about internationalisation and particularly IoC in relation to the two programs. Part of the significance of this study lies in the use of a number of conceptual and theoretical frameworks to extend the current body of literature beyond the main context of western higher education. An innovation in this study was the evaluation of the level of curriculum internationalisation at FTU, which was conducted using the model of curriculum internationalisation proposed by Huang (2017). Findings suggested that program managers and course coordinators worked collaboratively with their western partners to provide programs that they perceived as worthwhile in meeting the needs of the institution and the Vietnamese government agenda for internationalisation. However, academics were not generally well informed about the broader goals relating to IoC and found it challenging to accommodate the expectations with limited resources and lack of appropriate training.
- Description: Doctor of Philosophy
Investigating the configuration of a flight training device for visual flight rules navigation
- Authors: Harvey, William
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: The acquisition of pilot navigational skills utilising visual landmarks is a crucial skill that is required as part of Visual Flight Rules navigation towards obtaining a Private Pilot License. Due to the high cost of pilot training simulators, industry has identified a need for research in efficient utilisation of low-end, low cost personal compute flight simulators to assist in developing pilot skills. Analysis of the effectiveness of the use of such personal computer simulators depend on proper configuration determined by measurable errors to define simulator fidelity. To date, research has shown that the configuration of these simulators appears to have been done in an ad-hoc fashion and not in a scientific fashion. Therefore, the problem that needed to be solved was how to effectively configure such simulators. This thesis research attempted to solve this problem and present the process for effectively configuring a personal computer simulator, or flight training device, capable of successful Visual Flight Rules navigation. The simulator was configurated utilising a process that followed an interpretation of the Design Science research method, and an error correction model to determine the errors in the simulator configuration. This was done by comparing two probability distributions to measure the maximum error variable distance in order to configure a simulator suitable for the acquisition of Visual Flight Rules navigation piloting skills required for obtaining a Private Pilot Licence in Australia. This error identification method was then used to indicate simulator configuration efficiency and fidelity in order to achieve a minimum suitable configuration and setup. Further application of the findings of this research could potentially lead to the configuration of different types of non-aviation simulators, in particular Part-Task-Trainers and other training devices, including Virtual Reality Augmented Reality devices utilising various types of platforms such as Windows, Apple, and Android.
- Description: Doctor of Philosophy
- Authors: Harvey, William
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: The acquisition of pilot navigational skills utilising visual landmarks is a crucial skill that is required as part of Visual Flight Rules navigation towards obtaining a Private Pilot License. Due to the high cost of pilot training simulators, industry has identified a need for research in efficient utilisation of low-end, low cost personal compute flight simulators to assist in developing pilot skills. Analysis of the effectiveness of the use of such personal computer simulators depend on proper configuration determined by measurable errors to define simulator fidelity. To date, research has shown that the configuration of these simulators appears to have been done in an ad-hoc fashion and not in a scientific fashion. Therefore, the problem that needed to be solved was how to effectively configure such simulators. This thesis research attempted to solve this problem and present the process for effectively configuring a personal computer simulator, or flight training device, capable of successful Visual Flight Rules navigation. The simulator was configurated utilising a process that followed an interpretation of the Design Science research method, and an error correction model to determine the errors in the simulator configuration. This was done by comparing two probability distributions to measure the maximum error variable distance in order to configure a simulator suitable for the acquisition of Visual Flight Rules navigation piloting skills required for obtaining a Private Pilot Licence in Australia. This error identification method was then used to indicate simulator configuration efficiency and fidelity in order to achieve a minimum suitable configuration and setup. Further application of the findings of this research could potentially lead to the configuration of different types of non-aviation simulators, in particular Part-Task-Trainers and other training devices, including Virtual Reality Augmented Reality devices utilising various types of platforms such as Windows, Apple, and Android.
- Description: Doctor of Philosophy
Never afters : female friendship and collaboration in contemporary re-visioned fairy tales by women
- Authors: McDermott, Kirstyn
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Antagonism among girls and women in fairy tales has been the subject of much critical and popular discussion over recent decades. Significantly less attention, however, has been paid to the frequent absence of collaborative female relationships in traditional fairy tales and their contemporary retellings. Holding re-visioned fairy tales to be a type of feminist creative praxis, this thesis investigates how mutually beneficial relationships between female characters may be constructed within such narratives. “Never Afters” is a collection of six re-visions, written as sequels to well-known fairy tales from the Western European corpus. Situated within a genre that commonly isolates female characters or foregrounds female antagonism, each re-vision employs one (or more) of five key strategies that are used by contemporary authors to imagine collaborative female relationships within retold fairy tales: inversion, insertion/deletion, expansion, fusion, and extrapolation. The exegesis contextualises my creative work and assesses the strengths and limitations of each strategy by critically examining how they are used in contemporary fairy tales by authors including Emma Donoghue, Theodora Goss, Angela Slatter, Aimee Bender, and Kelly Link. I demonstrate that expansion, fusion, and extrapolation best allow authors to introduce new female characters and fresh feminist perspectives that move away from female exceptionalism and instead foreground female collaboration and friendship as potent sources of narrative power. The exegesis further argues that the cognitive sciences, and schema theories in particular, may offer insights as to why collaborative female relationships have received such scant representation. Using case studies of my own creative praxis, I explore the ways in which female isolation and acrimony are re-inscribed in contemporary work and recommend the adoption of new frameworks through which creative writers may critically and reflexively interrogate their tacit storytelling knowledge.
- Description: Doctor of Philosophy
- Authors: McDermott, Kirstyn
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Antagonism among girls and women in fairy tales has been the subject of much critical and popular discussion over recent decades. Significantly less attention, however, has been paid to the frequent absence of collaborative female relationships in traditional fairy tales and their contemporary retellings. Holding re-visioned fairy tales to be a type of feminist creative praxis, this thesis investigates how mutually beneficial relationships between female characters may be constructed within such narratives. “Never Afters” is a collection of six re-visions, written as sequels to well-known fairy tales from the Western European corpus. Situated within a genre that commonly isolates female characters or foregrounds female antagonism, each re-vision employs one (or more) of five key strategies that are used by contemporary authors to imagine collaborative female relationships within retold fairy tales: inversion, insertion/deletion, expansion, fusion, and extrapolation. The exegesis contextualises my creative work and assesses the strengths and limitations of each strategy by critically examining how they are used in contemporary fairy tales by authors including Emma Donoghue, Theodora Goss, Angela Slatter, Aimee Bender, and Kelly Link. I demonstrate that expansion, fusion, and extrapolation best allow authors to introduce new female characters and fresh feminist perspectives that move away from female exceptionalism and instead foreground female collaboration and friendship as potent sources of narrative power. The exegesis further argues that the cognitive sciences, and schema theories in particular, may offer insights as to why collaborative female relationships have received such scant representation. Using case studies of my own creative praxis, I explore the ways in which female isolation and acrimony are re-inscribed in contemporary work and recommend the adoption of new frameworks through which creative writers may critically and reflexively interrogate their tacit storytelling knowledge.
- Description: Doctor of Philosophy
Positive attitude change to school - Narrative inquiry into adolescent students' lived experiences
- Authors: Wojtaszek, Sylwia
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis reports on a qualitative research study that investigated adolescent students‟ experiences of positive attitude change to school. The literature review situates the research of students‟ attitude changes to school within the affective component of the multidimensional construct of student engagement and identifies this field and the phenomenon of positive attitude change to school as underresearched and under-theorised. Narrative inquiry methodology was applied in order to provide a detailed description of students‟ lived experiences and generate knowledge to fill the existing gap of how such an experience manifests itself. Eight students, who self-reported to have experienced positive attitude change to school, shared stories through in-depth semi-structured interviews of how the attitude change came about, who or what influenced it, and what meaning they attached to it in relation to its impact on their engagement and wellbeing. Students‟ attitudes to school are predominantly examined through quantitative research, whereas this study provided a unique and nuanced insight into attitude change based on the qualitative paradigm and a social constructionist view of the experience from the students‟ vantage point. Students‟ narrative accounts are compared and contrasted with each other to identify five resonant threads associated with the experience of positive attitude change to school. Data analysis suggests that positive attitude change to school has a significant impact on student engagement in learning and student wellbeing through its embodiment of perceived positive emotions associated with being at school. It consequently illustrates the relevance of broadening the understanding of such an experience to address the critical issue of disengagement in adolescent students. Key findings indicate that students develop a negative attitude to school when personal problems remain unresolved or have been insufficiently addressed within the school environment; no “helping hand” was there to assist these ambitious students who were struggling to engage in learning due to their experience of negative emotions at school. This research study has revealed that a negative attitude to school does not necessarily equate to a negative attitude to learning. Students‟ perception of the available support, both from the teachers and the services offered at school, is a critical factor in the transformation of their attitudes to school. Further, the students who participated in this study did not themselves feel that they were equipped with the required knowledge and skills to manage their personal problems effectively in order to maintain their engagement in learning. Only after having “hit rock bottom” and having sought help from outside the school environment were the students able to apply a different perspective to their circumstances that was associated with positive attitude change to school. From this research study it can be concluded that a student‟s positive attitude to school is a requirement for successful social and academic outcomes, and it is an educational goal in itself regarding the notion of developing lifelong learners. Personal problems and their impact on student engagement and wellbeing need to be acknowledged and catered for within the school environment. School support services must proactively extend a helping hand to students who have a negative attitude to school. Further, students need to develop selfefficacy regarding their personal wellbeing so that they become confident to act autonomously in solving their situations at school that are characterised by the difficult negative emotions that they are experiencing. Students‟ attitudes to school and the complexity of the multidimensional construct of student engagement need to be considered in the development of initiatives to address adolescent student disengagement and in the development of student wellbeing frameworks.
- Description: Doctor of Philosophy
- Authors: Wojtaszek, Sylwia
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis reports on a qualitative research study that investigated adolescent students‟ experiences of positive attitude change to school. The literature review situates the research of students‟ attitude changes to school within the affective component of the multidimensional construct of student engagement and identifies this field and the phenomenon of positive attitude change to school as underresearched and under-theorised. Narrative inquiry methodology was applied in order to provide a detailed description of students‟ lived experiences and generate knowledge to fill the existing gap of how such an experience manifests itself. Eight students, who self-reported to have experienced positive attitude change to school, shared stories through in-depth semi-structured interviews of how the attitude change came about, who or what influenced it, and what meaning they attached to it in relation to its impact on their engagement and wellbeing. Students‟ attitudes to school are predominantly examined through quantitative research, whereas this study provided a unique and nuanced insight into attitude change based on the qualitative paradigm and a social constructionist view of the experience from the students‟ vantage point. Students‟ narrative accounts are compared and contrasted with each other to identify five resonant threads associated with the experience of positive attitude change to school. Data analysis suggests that positive attitude change to school has a significant impact on student engagement in learning and student wellbeing through its embodiment of perceived positive emotions associated with being at school. It consequently illustrates the relevance of broadening the understanding of such an experience to address the critical issue of disengagement in adolescent students. Key findings indicate that students develop a negative attitude to school when personal problems remain unresolved or have been insufficiently addressed within the school environment; no “helping hand” was there to assist these ambitious students who were struggling to engage in learning due to their experience of negative emotions at school. This research study has revealed that a negative attitude to school does not necessarily equate to a negative attitude to learning. Students‟ perception of the available support, both from the teachers and the services offered at school, is a critical factor in the transformation of their attitudes to school. Further, the students who participated in this study did not themselves feel that they were equipped with the required knowledge and skills to manage their personal problems effectively in order to maintain their engagement in learning. Only after having “hit rock bottom” and having sought help from outside the school environment were the students able to apply a different perspective to their circumstances that was associated with positive attitude change to school. From this research study it can be concluded that a student‟s positive attitude to school is a requirement for successful social and academic outcomes, and it is an educational goal in itself regarding the notion of developing lifelong learners. Personal problems and their impact on student engagement and wellbeing need to be acknowledged and catered for within the school environment. School support services must proactively extend a helping hand to students who have a negative attitude to school. Further, students need to develop selfefficacy regarding their personal wellbeing so that they become confident to act autonomously in solving their situations at school that are characterised by the difficult negative emotions that they are experiencing. Students‟ attitudes to school and the complexity of the multidimensional construct of student engagement need to be considered in the development of initiatives to address adolescent student disengagement and in the development of student wellbeing frameworks.
- Description: Doctor of Philosophy
Random finite element method prediction and optimisation for open pit mine slope stability analysis
- Authors: Dyson, Ashley
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Inherent soil variability can have significant effects on the stability of open-pit mine slopes. In practice, the spatial variability of materials is not commonly considered as a routine component of slope stability analysis. The process of quantifying spatially variable parameters, as well as the modelling of their behaviour is often a complex undertaking. Currently, there are no large-scale commercial software packages containing in-built methods for modelling spatial variability within the Finite Element environment. Furthermore, conventional Limit Equilibrium Methods (LEM) incorporating spatial variability are unable to consider the stress/strain characteristics of these materials. The following research seeks to accurately model the slope mechanics of spatially variable soils, adopting The Random Finite Element Method (RFEM) developed by Griffiths and Fenton (2004) to determine slope failure mechanisms and safety factors. Techniques are developed to produce a set of optimised Random Finite Element Method simulations using the Monte Carlo Method. Additionally, random field analysis techniques are investigated to compare and categorise soil parameter fluctuation, providing a direct relationship between random field properties and slope failure surfaces. Optimisation and analysis techniques are implemented to examine the effects of cross-sectional geometries and input parameter distributions on failure mechanisms, safety factors and probabilities of failure. Cross-sectional RFEM analysis is performed in the Finite Element Method (FEM) software package Abaqus, with the techniques of this research demonstrated for a large open-pit brown coal mine located in the state of Victoria, Australia. The outcome of this research is a comprehensive procedure for optimised RFEM simulation and analysis.
- Description: Doctor of Philosophy
- Authors: Dyson, Ashley
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Inherent soil variability can have significant effects on the stability of open-pit mine slopes. In practice, the spatial variability of materials is not commonly considered as a routine component of slope stability analysis. The process of quantifying spatially variable parameters, as well as the modelling of their behaviour is often a complex undertaking. Currently, there are no large-scale commercial software packages containing in-built methods for modelling spatial variability within the Finite Element environment. Furthermore, conventional Limit Equilibrium Methods (LEM) incorporating spatial variability are unable to consider the stress/strain characteristics of these materials. The following research seeks to accurately model the slope mechanics of spatially variable soils, adopting The Random Finite Element Method (RFEM) developed by Griffiths and Fenton (2004) to determine slope failure mechanisms and safety factors. Techniques are developed to produce a set of optimised Random Finite Element Method simulations using the Monte Carlo Method. Additionally, random field analysis techniques are investigated to compare and categorise soil parameter fluctuation, providing a direct relationship between random field properties and slope failure surfaces. Optimisation and analysis techniques are implemented to examine the effects of cross-sectional geometries and input parameter distributions on failure mechanisms, safety factors and probabilities of failure. Cross-sectional RFEM analysis is performed in the Finite Element Method (FEM) software package Abaqus, with the techniques of this research demonstrated for a large open-pit brown coal mine located in the state of Victoria, Australia. The outcome of this research is a comprehensive procedure for optimised RFEM simulation and analysis.
- Description: Doctor of Philosophy
Robust Mobile Malware Detection
- Authors: Khoda, Mahbub
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: The increasing popularity and use of smartphones and hand-held devices have made them the most popular target for malware attackers. Researchers have proposed machine learning-based models to automatically detect malware attacks on these devices. Since these models learn application behaviors solely from the extracted features, choosing an appropriate and meaningful feature set is one of the most crucial steps for designing an effective mobile malware detection system. There are four categories of features for mobile applications. Previous works have taken arbitrary combinations of these categories to design models, resulting in sub-optimal performance. This thesis systematically investigates the individual impact of these feature categories on mobile malware detection systems. Feature categories that complement each other are investigated and categories that add redundancy to the feature space (thereby degrading the performance) are analyzed. In the process, the combination of feature categories that provides the best detection results is identified. Ensuring reliability and robustness of the above-mentioned malware detection systems is of utmost importance as newer techniques to break down such systems continue to surface. Adversarial attack is one such evasive attack that can bypass a detection system by carefully morphing a malicious sample even though the sample was originally correctly identified by the same system. Self-crafted adversarial samples can be used to retrain a model to defend against such attacks. However, randomly using too many such samples, as is currently done in the literature, can further degrade detection performance. This work proposed two intelligent approaches to retrain a classifier through the intelligent selection of adversarial samples. The first approach adopts a distance-based scheme where the samples are chosen based on their distance from malware and benign cluster centers while the second selects the samples based on a probability measure derived from a kernel-based learning method. The second method achieved a 6% improvement in terms of accuracy. To ensure practical deployment of malware detection systems, it is necessary to keep the real-world data characteristics in mind. For example, the benign applications deployed in the market greatly outnumber malware applications. However, most studies have assumed a balanced data distribution. Also, techniques to handle imbalanced data in other domains cannot be applied directly to mobile malware detection since they generate synthetic samples with broken functionality, making them invalid. In this regard, this thesis introduces a novel synthetic over-sampling technique that ensures valid sample generation. This technique is subsequently combined with a dynamic cost function in the learning scheme that automatically adjusts minority class weight during model training which counters the bias towards the majority class and stabilizes the model. This hybrid method provided a 9% improvement in terms of F1-score. Aiming to design a robust malware detection system, this thesis extensively studies machine learning-based mobile malware detection in terms of best feature category combination, resilience against evasive attacks, and practical deployment of detection models. Given the increasing technological advancements in mobile and hand-held devices, this study will be very useful for designing robust cybersecurity systems to ensure safe usage of these devices.
- Description: Doctor of Philosophy
- Authors: Khoda, Mahbub
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: The increasing popularity and use of smartphones and hand-held devices have made them the most popular target for malware attackers. Researchers have proposed machine learning-based models to automatically detect malware attacks on these devices. Since these models learn application behaviors solely from the extracted features, choosing an appropriate and meaningful feature set is one of the most crucial steps for designing an effective mobile malware detection system. There are four categories of features for mobile applications. Previous works have taken arbitrary combinations of these categories to design models, resulting in sub-optimal performance. This thesis systematically investigates the individual impact of these feature categories on mobile malware detection systems. Feature categories that complement each other are investigated and categories that add redundancy to the feature space (thereby degrading the performance) are analyzed. In the process, the combination of feature categories that provides the best detection results is identified. Ensuring reliability and robustness of the above-mentioned malware detection systems is of utmost importance as newer techniques to break down such systems continue to surface. Adversarial attack is one such evasive attack that can bypass a detection system by carefully morphing a malicious sample even though the sample was originally correctly identified by the same system. Self-crafted adversarial samples can be used to retrain a model to defend against such attacks. However, randomly using too many such samples, as is currently done in the literature, can further degrade detection performance. This work proposed two intelligent approaches to retrain a classifier through the intelligent selection of adversarial samples. The first approach adopts a distance-based scheme where the samples are chosen based on their distance from malware and benign cluster centers while the second selects the samples based on a probability measure derived from a kernel-based learning method. The second method achieved a 6% improvement in terms of accuracy. To ensure practical deployment of malware detection systems, it is necessary to keep the real-world data characteristics in mind. For example, the benign applications deployed in the market greatly outnumber malware applications. However, most studies have assumed a balanced data distribution. Also, techniques to handle imbalanced data in other domains cannot be applied directly to mobile malware detection since they generate synthetic samples with broken functionality, making them invalid. In this regard, this thesis introduces a novel synthetic over-sampling technique that ensures valid sample generation. This technique is subsequently combined with a dynamic cost function in the learning scheme that automatically adjusts minority class weight during model training which counters the bias towards the majority class and stabilizes the model. This hybrid method provided a 9% improvement in terms of F1-score. Aiming to design a robust malware detection system, this thesis extensively studies machine learning-based mobile malware detection in terms of best feature category combination, resilience against evasive attacks, and practical deployment of detection models. Given the increasing technological advancements in mobile and hand-held devices, this study will be very useful for designing robust cybersecurity systems to ensure safe usage of these devices.
- Description: Doctor of Philosophy
Special needs, special play? Examining the agency of children with impairments in play-based learning in a special school
- Authors: Claughton, Amy
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Play is an inherent part of childhood, often cast as an innate behaviour of children. Over the years, play has been scrutinised by theorists, researchers and educators alike in their attempts to understand how children engage in play, the role of play in development and how to identify, define and measure play. For children with impairments, play is frequently subjected to surveillance and compared to that of children whose development is considered typical. This thesis interrogates the play-based learning experiences of five children who attended a special educational school in rural Victoria, Australia. It examines the experiences that these children had in play and how teacher actions and responses enabled and supported their engagement in play-based learning. The theoretical framework for this study draws on critical ethnography underpinned by disability studies. Disability studies recognises the social model of disability, in which disability is a social construction. Using this model, impairment is distinct and separate from disability. In this study, socially constructed barriers that confront children in their play are identified as being created by attitudes, structures and environments (Bishop et al., 1999). These barriers are overlaid by the psycho-emotional dimensions of disability (C. Thomas, 1999) in an effort to represent the experiences of children as shaped by the actions and responses of others. This thesis introduces a new analytic tool in the learning portal framework. The learning portal framework aims to provide a platform through which teacher actions and responses can be analysed to understand how children are enabled to access play-based learning. The findings of this study indicate that children with impairments play in complex and nuanced ways. They show purpose in their play, are able to self-initiate, and independently investigate play-based learning experiences. Adult actions and responses often enable children with impairments to engage in play by offering opportunities and pathways for exploration. Indirect adult facilitation in play supports children’s ability to act in play with individuality and determination.
- Description: Doctor of Philosophy
- Authors: Claughton, Amy
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: Play is an inherent part of childhood, often cast as an innate behaviour of children. Over the years, play has been scrutinised by theorists, researchers and educators alike in their attempts to understand how children engage in play, the role of play in development and how to identify, define and measure play. For children with impairments, play is frequently subjected to surveillance and compared to that of children whose development is considered typical. This thesis interrogates the play-based learning experiences of five children who attended a special educational school in rural Victoria, Australia. It examines the experiences that these children had in play and how teacher actions and responses enabled and supported their engagement in play-based learning. The theoretical framework for this study draws on critical ethnography underpinned by disability studies. Disability studies recognises the social model of disability, in which disability is a social construction. Using this model, impairment is distinct and separate from disability. In this study, socially constructed barriers that confront children in their play are identified as being created by attitudes, structures and environments (Bishop et al., 1999). These barriers are overlaid by the psycho-emotional dimensions of disability (C. Thomas, 1999) in an effort to represent the experiences of children as shaped by the actions and responses of others. This thesis introduces a new analytic tool in the learning portal framework. The learning portal framework aims to provide a platform through which teacher actions and responses can be analysed to understand how children are enabled to access play-based learning. The findings of this study indicate that children with impairments play in complex and nuanced ways. They show purpose in their play, are able to self-initiate, and independently investigate play-based learning experiences. Adult actions and responses often enable children with impairments to engage in play by offering opportunities and pathways for exploration. Indirect adult facilitation in play supports children’s ability to act in play with individuality and determination.
- Description: Doctor of Philosophy
Stress resilience : meaning, measurement, and the effects of physical activity
- Authors: O’Donohue, Josephine
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: In rodent models of human behaviour, physical activity builds stress resilience. In contrast, human studies physical activity and stress resilience have been limited, and when investigated, provided mixed results. These inconsistencies may be due to the ambiguous use of the term stress resilience in human studies, making it difficult to quantify. Therefore, I aimed to assess the effect of physical activity on stress resilience in humans, after first evaluating operational definitions of stress resilience. Initially, I evaluated the use of stress resilience across the literature to provide a definition that is consistent with the research base (Chapter 2). I subsequently defined stress resilience as an active process of adapting to unpredictable and uncontrollable stimuli. In Chapter 3, I systematically reviewed measures previously used to capture stress resilience in humans, including trait-based questionnaires, as well as affective and cardiorespiratory responses to stressful conditions. In Study 1 (Chapter 4) of this dissertation, I then assessed the convergent validity of these stress resilience measures , including the Brief Resilience Scale and the Connor-Davidson Resilience Scale, as well as various responses (i.e., affective balance, systolic blood pressure, rate pressure product, and multiple indices of heart rate variability) to three stressor conditions (i.e., no stress, auditory startles, and stressful video clips). Results of Study 1 indicated that no measure captured all elements of stress resilience, although some indices of heart rate variability were related to changes in affective balance and systolic blood pressure was related to the Brief Resilience Scale. Across two studies, I then evaluated the effect of physical activity on stress resilience using the measures from Study 1. Through a cross-sectional study (Study 2, Chapter 5), I found no difference between active participants (n = 16) and less active participants (n = 14) across stress resilience measures. Additionally, in Study 3 (Chapter 6), I found that an 8-week moderate physical activity intervention had no effect on these stress resilience measures in 14 participants from desk-based occupations. I did, however, find an increase in mood and reduction in systolic blood pressure post-intervention, compared to pre-intervention scores. I also discussed the feasibility of various recruitment techniques, intervention purity and adherence, as well as stress resilience measurement protocols for future intervention studies. Overall, this dissertation has provided a critical evaluation of the use and measurement of stress resilience, with findings indicating that physical activity may not enhance stress resilience in humans. I discuss differences in my findings, compared to rodent research, including the potential effects of environment enrichment and increased severity of measurement protocols in animal models. I also discuss limitations of stress resilience conceptualisation and provide suggestions for future research to navigate these challenges.
- Description: Doctor of Philosophy
- Authors: O’Donohue, Josephine
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: In rodent models of human behaviour, physical activity builds stress resilience. In contrast, human studies physical activity and stress resilience have been limited, and when investigated, provided mixed results. These inconsistencies may be due to the ambiguous use of the term stress resilience in human studies, making it difficult to quantify. Therefore, I aimed to assess the effect of physical activity on stress resilience in humans, after first evaluating operational definitions of stress resilience. Initially, I evaluated the use of stress resilience across the literature to provide a definition that is consistent with the research base (Chapter 2). I subsequently defined stress resilience as an active process of adapting to unpredictable and uncontrollable stimuli. In Chapter 3, I systematically reviewed measures previously used to capture stress resilience in humans, including trait-based questionnaires, as well as affective and cardiorespiratory responses to stressful conditions. In Study 1 (Chapter 4) of this dissertation, I then assessed the convergent validity of these stress resilience measures , including the Brief Resilience Scale and the Connor-Davidson Resilience Scale, as well as various responses (i.e., affective balance, systolic blood pressure, rate pressure product, and multiple indices of heart rate variability) to three stressor conditions (i.e., no stress, auditory startles, and stressful video clips). Results of Study 1 indicated that no measure captured all elements of stress resilience, although some indices of heart rate variability were related to changes in affective balance and systolic blood pressure was related to the Brief Resilience Scale. Across two studies, I then evaluated the effect of physical activity on stress resilience using the measures from Study 1. Through a cross-sectional study (Study 2, Chapter 5), I found no difference between active participants (n = 16) and less active participants (n = 14) across stress resilience measures. Additionally, in Study 3 (Chapter 6), I found that an 8-week moderate physical activity intervention had no effect on these stress resilience measures in 14 participants from desk-based occupations. I did, however, find an increase in mood and reduction in systolic blood pressure post-intervention, compared to pre-intervention scores. I also discussed the feasibility of various recruitment techniques, intervention purity and adherence, as well as stress resilience measurement protocols for future intervention studies. Overall, this dissertation has provided a critical evaluation of the use and measurement of stress resilience, with findings indicating that physical activity may not enhance stress resilience in humans. I discuss differences in my findings, compared to rodent research, including the potential effects of environment enrichment and increased severity of measurement protocols in animal models. I also discuss limitations of stress resilience conceptualisation and provide suggestions for future research to navigate these challenges.
- Description: Doctor of Philosophy