Building an understanding of the development of OHS management in small business in the Victorian construction industry
- Authors: Leggett, Susan
- Date: 2009
- Type: Text , Thesis , PhD
- Full Text:
- Description: "Small businesses are regularly perceived to be poor performers in OHS management. However, attributing poor performance soley to size, to the hazardous nature of the industry or to a simplistic combination of both aspects neglects the recognition that there are some small businesses that can manage OHS with greater capacity than others."
- Description: Doctor of Philosophy
- Authors: Leggett, Susan
- Date: 2009
- Type: Text , Thesis , PhD
- Full Text:
- Description: "Small businesses are regularly perceived to be poor performers in OHS management. However, attributing poor performance soley to size, to the hazardous nature of the industry or to a simplistic combination of both aspects neglects the recognition that there are some small businesses that can manage OHS with greater capacity than others."
- Description: Doctor of Philosophy
Building social capital through the delivery of outdoor education at Victorian government schools
- Authors: Keeble, Tony
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis describes an explanatory sequential mixed-methods research project that investigated the changes to student social capital indicators resulting from an outdoor educational program, Future Maker, delivered to Victorian government school students. A systematic review of literature found minimal evidence of research relating to the change to social capital indicators as a result of programs that deliver outdoor education curriculum. The initial chapters of this thesis explore research on outdoor residential schools and the development of the Future Maker program as an alternative form of outdoor education curriculum design. Quantitative data were gathered from 287 students in the form of the Life Effectiveness Questionnaire (LEQ), over a 12-month period. Students completed the LEQ on three separate occasions: Day 1 of the program, Day 12 of the program, and 6 months after the program. Furthermore, qualitative data were gathered using a semistructured interview process. Twenty-eight students and seven teachers were randomly selected from participating schools to partake in the interviews. The final sections of the thesis present and discuss the findings from the quantitative and qualitative data that provided sufficient evidence that showed a significant increase in effect size for the social capital indicators of communication, relationships, group processing, networking and leadership. Furthermore, the research indicated that the domestic chores undertaken by students on an outdoor education program contributed to how social capital is learnt in an outdoor educational context. Moreover, the research positions outdoor education as a subject with content and pedagogy rather than a discipline and argues that outdoor education as a standalone subject has been sitting in plain sight. Finally, it concluded that a purpose-designed outdoor education program, which is built using a framework for curriculum development, can develop positive indicators for social capital.
- Description: Doctor of Philosophy
- Authors: Keeble, Tony
- Date: 2020
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis describes an explanatory sequential mixed-methods research project that investigated the changes to student social capital indicators resulting from an outdoor educational program, Future Maker, delivered to Victorian government school students. A systematic review of literature found minimal evidence of research relating to the change to social capital indicators as a result of programs that deliver outdoor education curriculum. The initial chapters of this thesis explore research on outdoor residential schools and the development of the Future Maker program as an alternative form of outdoor education curriculum design. Quantitative data were gathered from 287 students in the form of the Life Effectiveness Questionnaire (LEQ), over a 12-month period. Students completed the LEQ on three separate occasions: Day 1 of the program, Day 12 of the program, and 6 months after the program. Furthermore, qualitative data were gathered using a semistructured interview process. Twenty-eight students and seven teachers were randomly selected from participating schools to partake in the interviews. The final sections of the thesis present and discuss the findings from the quantitative and qualitative data that provided sufficient evidence that showed a significant increase in effect size for the social capital indicators of communication, relationships, group processing, networking and leadership. Furthermore, the research indicated that the domestic chores undertaken by students on an outdoor education program contributed to how social capital is learnt in an outdoor educational context. Moreover, the research positions outdoor education as a subject with content and pedagogy rather than a discipline and argues that outdoor education as a standalone subject has been sitting in plain sight. Finally, it concluded that a purpose-designed outdoor education program, which is built using a framework for curriculum development, can develop positive indicators for social capital.
- Description: Doctor of Philosophy
Cadmium and human prostatic carcinoma : a study of the analytical procedures for the determination of cadmium and zinc in human prostatic tissue, and the investigation of an association between the incidence of prosatatic adencarcinoma and the occurrence of prostatic cadmium
- Authors: Moran, Robert
- Date: 1994
- Type: Text , Thesis , Masters
- Full Text: false
- Description: The concentrations of the heavy metals cadmium and zinc in both benign nodular hyperplastic and malignant (adenocarcinoma) human prostatic tissue obtained from Trans Urethral Resections of the Prostate (TURP) have been investigated. Healthy normal human prostates obtained from post mortem cadavers were used as controls. The change in the prostatic cadmium concentration with age was investigated. Renal cortex cadmium and zinc concentration changes with age together with the metal concentration intterelationships between prostatic and renal cortex tissues were studied. "From abstract"
- Description: Master of Applied Science
- Authors: Moran, Robert
- Date: 1994
- Type: Text , Thesis , Masters
- Full Text: false
- Description: The concentrations of the heavy metals cadmium and zinc in both benign nodular hyperplastic and malignant (adenocarcinoma) human prostatic tissue obtained from Trans Urethral Resections of the Prostate (TURP) have been investigated. Healthy normal human prostates obtained from post mortem cadavers were used as controls. The change in the prostatic cadmium concentration with age was investigated. Renal cortex cadmium and zinc concentration changes with age together with the metal concentration intterelationships between prostatic and renal cortex tissues were studied. "From abstract"
- Description: Master of Applied Science
Canonical Dual Algorithms for Global Optimization with Applications
- Authors: Zhou, Xiaojun
- Date: 2014
- Type: Text , Thesis
- Full Text:
- Description: Canonical duality theory provides a unified framework which can transform a nonconvex primal minimization problem to a canonical dual maximization problem over a convex domain without duality gap. But the global optimality is guaranteed by a certain positive definite condition and such condition is not always satisfied. The goal of this thesis aims to explore possible techniques that can be used to solve global optimization problems based on the canonical duality theory. Firstly, an algorithmic framework for canonical duality theory is established, which shows that the canonical dual algorithms can be developed in four aspects under the positive definite condition explicitly or implicitly, namely, (i) minimizing the primal problem, (ii) maximizing the canonical dual problem, (iii) solving a nonlinear equation caused by total complementary function, and (iv) solving a nonlinear equation caused by canonical dual function. Secondly, we show that if there exists a critical point of the canonical dual problem in the positive definite domain, by solving an equivalent semidefinite programming (SDP) problem, the corresponding global solution to the primal problem can be obtained easily via off-the-shelf software packages. A specific canonical dual algorithm is given for each problem, including sum of fourth-order polynomials minimization, nonconvex quadratically constrained quadratic program (QCQP), and boolean quadratic program (BQP). Thirdly, we propose a canonical primal-dual algorithm framework based on the total complementary function. Convergence analysis is discussed from the perspective of variational inequalities (VIs) and contraction methods. Specific canonical primal-dual algorithms for sum of fourth-order polynomials minimization is given as well. And a real-world application to the sensor network localization problem is illustrated. Next, a canonical sequential reduction approach is proposed to recover the approximate or global solution for the BQP problem. By fixing some previously known components, the original problem can be reduced sequentially to a lower dimension one. This approach is successfully applied to the well-known maxcut problem. Finally, we discuss the canonical dual approach applied to continuous time constrained optimal control. And it shows that the optimal control law for the n-dimensional constrained linear quadratic regulator can be achieved precisely via one-dimensional canonical dual variable, and for the optimal control problem with concave cost functional, an approximate solution can be obtained by introducing a linear perturbation term.
- Description: PhD
- Authors: Zhou, Xiaojun
- Date: 2014
- Type: Text , Thesis
- Full Text:
- Description: Canonical duality theory provides a unified framework which can transform a nonconvex primal minimization problem to a canonical dual maximization problem over a convex domain without duality gap. But the global optimality is guaranteed by a certain positive definite condition and such condition is not always satisfied. The goal of this thesis aims to explore possible techniques that can be used to solve global optimization problems based on the canonical duality theory. Firstly, an algorithmic framework for canonical duality theory is established, which shows that the canonical dual algorithms can be developed in four aspects under the positive definite condition explicitly or implicitly, namely, (i) minimizing the primal problem, (ii) maximizing the canonical dual problem, (iii) solving a nonlinear equation caused by total complementary function, and (iv) solving a nonlinear equation caused by canonical dual function. Secondly, we show that if there exists a critical point of the canonical dual problem in the positive definite domain, by solving an equivalent semidefinite programming (SDP) problem, the corresponding global solution to the primal problem can be obtained easily via off-the-shelf software packages. A specific canonical dual algorithm is given for each problem, including sum of fourth-order polynomials minimization, nonconvex quadratically constrained quadratic program (QCQP), and boolean quadratic program (BQP). Thirdly, we propose a canonical primal-dual algorithm framework based on the total complementary function. Convergence analysis is discussed from the perspective of variational inequalities (VIs) and contraction methods. Specific canonical primal-dual algorithms for sum of fourth-order polynomials minimization is given as well. And a real-world application to the sensor network localization problem is illustrated. Next, a canonical sequential reduction approach is proposed to recover the approximate or global solution for the BQP problem. By fixing some previously known components, the original problem can be reduced sequentially to a lower dimension one. This approach is successfully applied to the well-known maxcut problem. Finally, we discuss the canonical dual approach applied to continuous time constrained optimal control. And it shows that the optimal control law for the n-dimensional constrained linear quadratic regulator can be achieved precisely via one-dimensional canonical dual variable, and for the optimal control problem with concave cost functional, an approximate solution can be obtained by introducing a linear perturbation term.
- Description: PhD
Canonical dual finite element method for solving nonconvex mechanics and topology optimization
- Authors: Ali, Elaf
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Canonical duality theory (CDT) is a newly developed, potentially powerful methodological theory which can transfer general multi-scale nonconvex/discrete problems in Rn to a unified convex dual problem in continuous space Rm with m n and without a duality gap. The associated triality theory provides extremality criteria for both global and local optimal solutions, which can be used to develop powerful algorithms for solving general nonconvex variational problems. This thesis, first, presents a detailed study of large deformation problems in 2-D structural system. Based on the canonical duality theory, a canonical dual finite element method is applied to find a global minimization to the general nonconvex optimization problem using a new primal-dual semi-definite programming algorithm. Applications are illustrated by numerical examples with different structural designs and different external loads. Next, a new methodology and algorithm for solving post buckling problems of a large deformed elastic beam is investigated. The total potential energy of this beam is a nonconvex functional, which can be used to model both pre- and post-buckling phenomena. By using the canonical dual finite element method, a new primal-dual semi-definite programming algorithm is presented, which can be used to obtain all possible post-buckled solutions. In order to verify the triality theory, mixed meshes of different dual stress interpolation are applied to obtain the closed dimensions between discretized displacement and discretized stress. Applications are illustrated by several numerical examples with different boundary conditions. We find that the global minimum solution of the nonconvex potential leads to the unbuckled state, and both of these two solutions are numerically stable. However, the local minimum solution leads to an unstable buckled state, which is very sensitive to the external load, thickness of the beam, numerical precision, and the size of finite elements. Finally, a mathematically rigorous and computationally powerful method for solving 3-D topology optimization problems is demonstrated. This method is based on CDT developed by Gao in nonconvex mechanics and global optimization. It shows that the so-called NP-hard Knapsack problem in topology optimization can be solved deterministically in polynomial-time via a canonical penalty-duality (CPD) method to obtain precise global optimal 0-1 density distribution at each volume evolution. The relation between this CPD method and Gao's pure complementary energy principle is revealed for the first time. A CPD algorithm is proposed for 3-D topology optimization of linear elastic structures. Its novelty is demonstrated by benchmark problems. Results show that without using any artificial technique, the CPD method can provide mechanically sound optimal design, also it is much more powerful than the well-known BESO and SIMP methods. Finally, computational complexity and conceptual/mathematical mistakes in topology optimization modeling and popular methods are explicitly addressed.
- Description: Doctor of Philosophy
- Description: Canonical duality theory (CDT) is a newly developed, potentially powerful method- ological theory which can transfer general multi-scale nonconvex/discrete problems in Rn to a unified convex dual problem in continuous space Rm with m
- Authors: Ali, Elaf
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Canonical duality theory (CDT) is a newly developed, potentially powerful methodological theory which can transfer general multi-scale nonconvex/discrete problems in Rn to a unified convex dual problem in continuous space Rm with m n and without a duality gap. The associated triality theory provides extremality criteria for both global and local optimal solutions, which can be used to develop powerful algorithms for solving general nonconvex variational problems. This thesis, first, presents a detailed study of large deformation problems in 2-D structural system. Based on the canonical duality theory, a canonical dual finite element method is applied to find a global minimization to the general nonconvex optimization problem using a new primal-dual semi-definite programming algorithm. Applications are illustrated by numerical examples with different structural designs and different external loads. Next, a new methodology and algorithm for solving post buckling problems of a large deformed elastic beam is investigated. The total potential energy of this beam is a nonconvex functional, which can be used to model both pre- and post-buckling phenomena. By using the canonical dual finite element method, a new primal-dual semi-definite programming algorithm is presented, which can be used to obtain all possible post-buckled solutions. In order to verify the triality theory, mixed meshes of different dual stress interpolation are applied to obtain the closed dimensions between discretized displacement and discretized stress. Applications are illustrated by several numerical examples with different boundary conditions. We find that the global minimum solution of the nonconvex potential leads to the unbuckled state, and both of these two solutions are numerically stable. However, the local minimum solution leads to an unstable buckled state, which is very sensitive to the external load, thickness of the beam, numerical precision, and the size of finite elements. Finally, a mathematically rigorous and computationally powerful method for solving 3-D topology optimization problems is demonstrated. This method is based on CDT developed by Gao in nonconvex mechanics and global optimization. It shows that the so-called NP-hard Knapsack problem in topology optimization can be solved deterministically in polynomial-time via a canonical penalty-duality (CPD) method to obtain precise global optimal 0-1 density distribution at each volume evolution. The relation between this CPD method and Gao's pure complementary energy principle is revealed for the first time. A CPD algorithm is proposed for 3-D topology optimization of linear elastic structures. Its novelty is demonstrated by benchmark problems. Results show that without using any artificial technique, the CPD method can provide mechanically sound optimal design, also it is much more powerful than the well-known BESO and SIMP methods. Finally, computational complexity and conceptual/mathematical mistakes in topology optimization modeling and popular methods are explicitly addressed.
- Description: Doctor of Philosophy
- Description: Canonical duality theory (CDT) is a newly developed, potentially powerful method- ological theory which can transfer general multi-scale nonconvex/discrete problems in Rn to a unified convex dual problem in continuous space Rm with m
Canonical Duality Theory for Global Optimization problems and applications
- Chen, Yi
- Authors: Chen, Yi
- Date: 2015
- Type: Text , Thesis , PhD
- Full Text:
- Description: The canonical duality theory is studied, through a discussion on a general global optimization problem and applications on fundamentally important problems. This general problem is a formulation of the minimization problem with inequality constraints, where the objective function and constraints are any convex or nonconvex functions satisfying certain decomposition conditions. It covers convex problems, mixed integer programming problems and many other nonlinear programming problems. The three main parts of the canonical duality theory are canonical dual transformation, complementary-dual principle and triality theory. The complementary-dual principle is further developed, which conventionally states that each critical point of the canonical dual problem is corresponding to a KKT point of the primal problem with their sharing the same function value. The new result emphasizes that there exists a one-to-one correspondence between KKT points of the dual problem and of the primal problem and each pair of the corresponding KKT points share the same function value, which implies that there is truly no duality gap between the canonical dual problem and the primal problem. The triality theory reveals insightful information about global and local solutions. It is shown that as long as the global optimality condition holds true, the primal problem is equivalent to a convex problem in the dual space, which can be solved efficiently by existing convex methods; even if the condition does not hold, the convex problem still provides a lower bound that is at least as good as that by the Lagrangian relaxation method. It is also shown that through examining the canonical dual problem, the hidden convexity of the primal problem is easily observable. The canonical duality theory is then applied to dealing with three fundamentally important problems. The first one is the spherically constrained quadratic problem, also referred to as the trust region subproblem. The canonical dual problem is onedimensional and it is proved that the primal problem, no matter with convex or nonconvex objective function, is equivalent to a convex problem in the dual space. Moreover, conditions are found which comprise the boundary that separates instances into “hard case” and “easy case”. A canonical primal-dual algorithm is developed, which is able to efficiently solve the problem, including the “hard case”, and can be used as a unified method for similar problems. The second one is the binary quadratic problem, a fundamental problem in discrete optimization. The discussion is focused on lower bounds and analytically solvable cases, which are obtained by analyzing the canonical dual problem with perturbation techniques. The third one is a general nonconvex problem with log-sum-exp functions and quartic polynomials. It arises widely in engineering science and it can be used to approximate nonsmooth optimization problems. The work shows that problems can still be efficiently solved, via the canonical duality approach, even if they are nonconvex and nonsmooth.
- Description: Doctor of Philosophy
- Authors: Chen, Yi
- Date: 2015
- Type: Text , Thesis , PhD
- Full Text:
- Description: The canonical duality theory is studied, through a discussion on a general global optimization problem and applications on fundamentally important problems. This general problem is a formulation of the minimization problem with inequality constraints, where the objective function and constraints are any convex or nonconvex functions satisfying certain decomposition conditions. It covers convex problems, mixed integer programming problems and many other nonlinear programming problems. The three main parts of the canonical duality theory are canonical dual transformation, complementary-dual principle and triality theory. The complementary-dual principle is further developed, which conventionally states that each critical point of the canonical dual problem is corresponding to a KKT point of the primal problem with their sharing the same function value. The new result emphasizes that there exists a one-to-one correspondence between KKT points of the dual problem and of the primal problem and each pair of the corresponding KKT points share the same function value, which implies that there is truly no duality gap between the canonical dual problem and the primal problem. The triality theory reveals insightful information about global and local solutions. It is shown that as long as the global optimality condition holds true, the primal problem is equivalent to a convex problem in the dual space, which can be solved efficiently by existing convex methods; even if the condition does not hold, the convex problem still provides a lower bound that is at least as good as that by the Lagrangian relaxation method. It is also shown that through examining the canonical dual problem, the hidden convexity of the primal problem is easily observable. The canonical duality theory is then applied to dealing with three fundamentally important problems. The first one is the spherically constrained quadratic problem, also referred to as the trust region subproblem. The canonical dual problem is onedimensional and it is proved that the primal problem, no matter with convex or nonconvex objective function, is equivalent to a convex problem in the dual space. Moreover, conditions are found which comprise the boundary that separates instances into “hard case” and “easy case”. A canonical primal-dual algorithm is developed, which is able to efficiently solve the problem, including the “hard case”, and can be used as a unified method for similar problems. The second one is the binary quadratic problem, a fundamental problem in discrete optimization. The discussion is focused on lower bounds and analytically solvable cases, which are obtained by analyzing the canonical dual problem with perturbation techniques. The third one is a general nonconvex problem with log-sum-exp functions and quartic polynomials. It arises widely in engineering science and it can be used to approximate nonsmooth optimization problems. The work shows that problems can still be efficiently solved, via the canonical duality approach, even if they are nonconvex and nonsmooth.
- Description: Doctor of Philosophy
Capital budgeting practices and firm performance : A comparative study of Australia and Sri Lanka
- Puwanenthiren, Pratheepkanth
- Authors: Puwanenthiren, Pratheepkanth
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis disentangles two elements from the complex interdependent suite of key drivers of firm sophistication in capital-budgeting. Specifically, the relative sophistication of a firm (i.e. its nature) and the development level of the nation in which a firm is embedded (i.e. the nurture experienced by the firm). This research should enhance the development focus and process of nations (e.g., to what degree should national development be about raising the ability of individual firms or will raising national development act as a rising tide [that] raises all boats). The comparative data used in this study comes from 150 Australian (ASX200-index-listed) firms and 150 Sri Lankan (Colombo-stock-exchange-listed firms). The research questions are answered via a quantitative research design that uses primary and secondary data. The response rate to the questionnaire survey of firms was, 45 and 73 completed questionnaires from, respectively, Australia and Sri Lanka (an effective response rate of, respectively, 31.5 and 48.7 percent). Secondary data for 2003-12 are obtained from the ASX, CSE’s and SIRCA databases and are used to calculate return on assets, return on equity, Tobin Q, and earnings per share for the sampled firms. It was found that Australian firms tend to rely heavily on sophisticated capital-budgeting practices, but Sri Lankan relatively small firms prefer simple analysis methods and the larger firms tend to be as adept at sophisticated capital budgeting as their Australian counterparts. The choice of whether to use more sophisticated practices or simpler alternatives varies with a firm’s attributes as well as the level of economic and financial market development in its environment. Also, Australian firms tend to use capital-budget models with good-to-strong predictive power (except for ROE) and Sri Lankan firms tend to use capital-budget models with fair-to-poor predictive power. Further, the analysis of Australian firms tends to yield stronger and more statistically-significant results, than those generated by Sri Lankan firms.
- Description: Doctor of Philosophy
- Authors: Puwanenthiren, Pratheepkanth
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis disentangles two elements from the complex interdependent suite of key drivers of firm sophistication in capital-budgeting. Specifically, the relative sophistication of a firm (i.e. its nature) and the development level of the nation in which a firm is embedded (i.e. the nurture experienced by the firm). This research should enhance the development focus and process of nations (e.g., to what degree should national development be about raising the ability of individual firms or will raising national development act as a rising tide [that] raises all boats). The comparative data used in this study comes from 150 Australian (ASX200-index-listed) firms and 150 Sri Lankan (Colombo-stock-exchange-listed firms). The research questions are answered via a quantitative research design that uses primary and secondary data. The response rate to the questionnaire survey of firms was, 45 and 73 completed questionnaires from, respectively, Australia and Sri Lanka (an effective response rate of, respectively, 31.5 and 48.7 percent). Secondary data for 2003-12 are obtained from the ASX, CSE’s and SIRCA databases and are used to calculate return on assets, return on equity, Tobin Q, and earnings per share for the sampled firms. It was found that Australian firms tend to rely heavily on sophisticated capital-budgeting practices, but Sri Lankan relatively small firms prefer simple analysis methods and the larger firms tend to be as adept at sophisticated capital budgeting as their Australian counterparts. The choice of whether to use more sophisticated practices or simpler alternatives varies with a firm’s attributes as well as the level of economic and financial market development in its environment. Also, Australian firms tend to use capital-budget models with good-to-strong predictive power (except for ROE) and Sri Lankan firms tend to use capital-budget models with fair-to-poor predictive power. Further, the analysis of Australian firms tends to yield stronger and more statistically-significant results, than those generated by Sri Lankan firms.
- Description: Doctor of Philosophy
Cardiovascular data analytics for real time patient monitoring
- Authors: Allami, Ragheed
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Improvements in wearable sensor devices make it possible to constantly monitor physiological parameters such as electrocardiograph (ECG) signals for long periods. Remote patient monitoring with wearable sensors has an important role to play in health care, particularly given the prevalence of chronic conditions such as cardiovascular disease (CVD)—one of the prominent causes of morbidity and mortality worldwide. Approximately 4.2 million Australians suffer from long-term CVD with approximately one death every 12 minutes. The assessment of ECG features, especially heart rate variability (HRV), represents a non-invasive technique which provides an indication of the autonomic nervous system (ANS) function. Conditions such as sudden cardiac death, hypertension, heart failure, myocardial infarction, ischaemia, and coronary heart disease can be detected from HRV analysis. In addition, the analysis of ECG features can also be used to diagnose many types of life-threatening arrhythmias, including ventricular fibrillation and ventricular tachycardia. Non-cardiac conditions, such as diabetes, obesity, metabolic syndrome, insulin resistance, irritable bowel syndrome, dyspepsia, anorexia nervosa, anxiety, and major depressive disorder have also been shown to be associated with HRV. The analysis of ECG features from real time ECG signals generated from wearable sensors provides distinctive challenges. The sensors that receive and process the signals have limited power, storage and processing capacity. Consequently, algorithms that process ECG signals need to be lightweight, use minimal storage resources and accurately detect abnormalities so that alarms can be raised. The existing literature details only a few algorithms which operate within the constraints of wearable sensor networks. This research presents four novel techniques that enable ECG signals to be processed within the limitations of resource constraints on devices to detect some key abnormalities in heart function. - The first technique is a novel real-time ECG data reduction algorithm, which detects and transmits only those key points that are critical for the generation of ECG features for diagnoses. - The second technique accurately predicts the five-minute HRV measure using only three minutes of data with an algorithm that executes in real-time using minimal computational resources. - The third technique introduces a real-time ECG feature recognition system that can be applied to diagnose life threatening conditions such as premature ventricular contractions (PVCs). - The fourth technique advances a classification algorithm to enhance the performance of automated ECG classification to determine arrhythmic heart beats based on noisy ECG signals. The four novel techniques are evaluated in comparison with benchmark algorithms for each task on the standard MIT-BIH Arrhythmia Database and with data generated from patients in a major hospital using Shimmer3 wearable ECG sensors. The four techniques are integrated to demonstrate that remote patient monitoring of ECG using HRV and ECG features is feasible in real time using minimal computational resources. The evaluation show that the ECG reduction algorithm is significantly better than existing algorithms that can be applied within sensor nodes, such as time-domain methods, transformation methods and compressed sensing methods. Furthermore, the proposed ECG reduction is found to be computationally less complex for resource constrained sensors and achieves higher compression ratios than existing algorithms. The prediction of a common HRV measure, the five-minute standard deviation of inter-beat variations (SDNN) and the accurate detection of PVC beats was achieved using a Count Data Model, combined with a Poisson-generated function from three-minute ECG recordings. This was achieved with minimal computational resources and was well suited to remote patient monitoring with wearable sensors. The PVC beats detection was implemented using the same count data model together with knowledge-based rules derived from clinical knowledge. A real-time cardiac patient monitoring system was implemented using an ECG sensor and smartphone to detect PVC beats within a few seconds using artificial neural networks (ANN), and it was proven to provide highly accurate results. The automated detection and classification were implemented using a new wrapper-based hybrid approach that utilized t-distributed stochastic neighbour embedding (t-SNE) in combination with self-organizing maps (SOM) to improve classification performance. The t-SNE-SOM hybrid resulted in improved sensitivity, specificity and accuracy compared to most common hybrid methods in the presence of noise. It also provided a better, more accurate identification for the presence of many types of arrhythmias from the ECG recordings, leading to a more timely diagnosis and treatment outcome.
- Description: Doctor of Philosophy
- Authors: Allami, Ragheed
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Improvements in wearable sensor devices make it possible to constantly monitor physiological parameters such as electrocardiograph (ECG) signals for long periods. Remote patient monitoring with wearable sensors has an important role to play in health care, particularly given the prevalence of chronic conditions such as cardiovascular disease (CVD)—one of the prominent causes of morbidity and mortality worldwide. Approximately 4.2 million Australians suffer from long-term CVD with approximately one death every 12 minutes. The assessment of ECG features, especially heart rate variability (HRV), represents a non-invasive technique which provides an indication of the autonomic nervous system (ANS) function. Conditions such as sudden cardiac death, hypertension, heart failure, myocardial infarction, ischaemia, and coronary heart disease can be detected from HRV analysis. In addition, the analysis of ECG features can also be used to diagnose many types of life-threatening arrhythmias, including ventricular fibrillation and ventricular tachycardia. Non-cardiac conditions, such as diabetes, obesity, metabolic syndrome, insulin resistance, irritable bowel syndrome, dyspepsia, anorexia nervosa, anxiety, and major depressive disorder have also been shown to be associated with HRV. The analysis of ECG features from real time ECG signals generated from wearable sensors provides distinctive challenges. The sensors that receive and process the signals have limited power, storage and processing capacity. Consequently, algorithms that process ECG signals need to be lightweight, use minimal storage resources and accurately detect abnormalities so that alarms can be raised. The existing literature details only a few algorithms which operate within the constraints of wearable sensor networks. This research presents four novel techniques that enable ECG signals to be processed within the limitations of resource constraints on devices to detect some key abnormalities in heart function. - The first technique is a novel real-time ECG data reduction algorithm, which detects and transmits only those key points that are critical for the generation of ECG features for diagnoses. - The second technique accurately predicts the five-minute HRV measure using only three minutes of data with an algorithm that executes in real-time using minimal computational resources. - The third technique introduces a real-time ECG feature recognition system that can be applied to diagnose life threatening conditions such as premature ventricular contractions (PVCs). - The fourth technique advances a classification algorithm to enhance the performance of automated ECG classification to determine arrhythmic heart beats based on noisy ECG signals. The four novel techniques are evaluated in comparison with benchmark algorithms for each task on the standard MIT-BIH Arrhythmia Database and with data generated from patients in a major hospital using Shimmer3 wearable ECG sensors. The four techniques are integrated to demonstrate that remote patient monitoring of ECG using HRV and ECG features is feasible in real time using minimal computational resources. The evaluation show that the ECG reduction algorithm is significantly better than existing algorithms that can be applied within sensor nodes, such as time-domain methods, transformation methods and compressed sensing methods. Furthermore, the proposed ECG reduction is found to be computationally less complex for resource constrained sensors and achieves higher compression ratios than existing algorithms. The prediction of a common HRV measure, the five-minute standard deviation of inter-beat variations (SDNN) and the accurate detection of PVC beats was achieved using a Count Data Model, combined with a Poisson-generated function from three-minute ECG recordings. This was achieved with minimal computational resources and was well suited to remote patient monitoring with wearable sensors. The PVC beats detection was implemented using the same count data model together with knowledge-based rules derived from clinical knowledge. A real-time cardiac patient monitoring system was implemented using an ECG sensor and smartphone to detect PVC beats within a few seconds using artificial neural networks (ANN), and it was proven to provide highly accurate results. The automated detection and classification were implemented using a new wrapper-based hybrid approach that utilized t-distributed stochastic neighbour embedding (t-SNE) in combination with self-organizing maps (SOM) to improve classification performance. The t-SNE-SOM hybrid resulted in improved sensitivity, specificity and accuracy compared to most common hybrid methods in the presence of noise. It also provided a better, more accurate identification for the presence of many types of arrhythmias from the ECG recordings, leading to a more timely diagnosis and treatment outcome.
- Description: Doctor of Philosophy
Care leavers recovering voice and agency through counter-narratives
- Authors: Golding, Frank
- Date: 2021
- Type: Text , Thesis , PhD
- Full Text:
- Description: The publications in this thesis discuss recurring issues in the historical context of out-of-home Care (OOHC). They were written for various audiences but are arranged not by date of publication but thematically so as to present a coherent argument about the recovery of voice and agency by those who experienced OOHC. The thesis begins with an Overview which discusses autoethnographic and multi-layered approaches to history and shows how subject matter helps determine the choice of methodology and sources and, in turn, how methodologies influence the selection of sources and shape content. Authorities in Australia have a long history of removing children from their families when they are deemed to be neglected or ‘in moral danger’. Out of the public gaze, these children were often rendered silent, their voices simply unheard or deliberately supressed by the exercise of total institutional power. This thesis analyses how children were marginalised, cast as ‘the other’, and framed as deserving no better than they got. In the aftermath of a series of inquiries into institutional child maltreatment—some of which came about as a result of survivor advocacy and relied heavily on direct testimony—we now better understand children’s institutional experiences. In this changing environment, advocacy groups are effectively challenging the received accounts of historical Care. Their challenge has gained impetus from the opening up of records through rights legislation, especially access to personal case files. Large numbers of Care leavers have found their files inaccurate, incomplete, or misleading, and this discovery has stimulated many to produce compelling counter-narratives of the lived experiences of their childhood, and the living experiences that endure. The thesis concludes with an extended analytical commentary reflecting new interpretations of emerging histories, assessing changes in the status of Care leavers, and identifying directions warranting further development in OOHC.
- Description: Doctor of Philosophy
- Authors: Golding, Frank
- Date: 2021
- Type: Text , Thesis , PhD
- Full Text:
- Description: The publications in this thesis discuss recurring issues in the historical context of out-of-home Care (OOHC). They were written for various audiences but are arranged not by date of publication but thematically so as to present a coherent argument about the recovery of voice and agency by those who experienced OOHC. The thesis begins with an Overview which discusses autoethnographic and multi-layered approaches to history and shows how subject matter helps determine the choice of methodology and sources and, in turn, how methodologies influence the selection of sources and shape content. Authorities in Australia have a long history of removing children from their families when they are deemed to be neglected or ‘in moral danger’. Out of the public gaze, these children were often rendered silent, their voices simply unheard or deliberately supressed by the exercise of total institutional power. This thesis analyses how children were marginalised, cast as ‘the other’, and framed as deserving no better than they got. In the aftermath of a series of inquiries into institutional child maltreatment—some of which came about as a result of survivor advocacy and relied heavily on direct testimony—we now better understand children’s institutional experiences. In this changing environment, advocacy groups are effectively challenging the received accounts of historical Care. Their challenge has gained impetus from the opening up of records through rights legislation, especially access to personal case files. Large numbers of Care leavers have found their files inaccurate, incomplete, or misleading, and this discovery has stimulated many to produce compelling counter-narratives of the lived experiences of their childhood, and the living experiences that endure. The thesis concludes with an extended analytical commentary reflecting new interpretations of emerging histories, assessing changes in the status of Care leavers, and identifying directions warranting further development in OOHC.
- Description: Doctor of Philosophy
Casuarina pauper (belah) woodlands of northwest Victoria : monitoring and regeneration
- Authors: Callister, Katrina
- Date: 2004
- Type: Text , Thesis , Masters , PhD
- Full Text:
- Description: "The study focused on C. pauper woodland in northwest Victoria, an area where the recent establishment of the Murray-Sunset National Park (MSNP) provides an ideal opportunity to manage these woodlands to promote regeneration"
- Description: Doctor of Philosophy
- Authors: Callister, Katrina
- Date: 2004
- Type: Text , Thesis , Masters , PhD
- Full Text:
- Description: "The study focused on C. pauper woodland in northwest Victoria, an area where the recent establishment of the Murray-Sunset National Park (MSNP) provides an ideal opportunity to manage these woodlands to promote regeneration"
- Description: Doctor of Philosophy
Causes, magnitude and implications of Griefing in Massively Multiplayer Online Role-Playing Games
- Authors: Achterbosch, Leigh
- Date: 2015
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis presents findings from research into the global phenomenon known as griefing that occurs in Massively Multiplayer Online Role-Playing Games (MMORPGs). Griefing, in its simplest terms, refers to the act of one player intentionally disrupting another player’s game experience for personal pleasure and potential gain. For too long it has been unknown how pervasive griefing is, how frequently griefing occurs and, in particular, the impact on players that are subjected to griefing. There has also been limited research regarding what causes a player to perform griefing. This thesis addresses these concerns by answering the research question “What are the causes and implications of griefing in Massively Multiplayer Online Role-Playing Games, and what magnitude of griefing exists in this genre?” Mixed method research was employed using the “Sequential Explanatory Strategy”, in which a quantitative phase was followed by a qualitative phase to strengthen the findings. The quantitative phase consisted of a survey that attracted 1188 participants of a representative player population. The qualitative phase consisted of interviews with 15 participants to give more personalised data. The data was analysed from the perspectives of different demographics and different associations to griefing. The thesis contributed original findings regarding the causes, magnitude and implications of griefing in MMORPGs. Some of the main findings were: • Factors that motivated a player to cause grief; • how griefers selected their targets based on particular demographics or avatar characteristics; • the pervasiveness, frequency and impact of different types of griefing; • the amount of griefing that can be tolerated; • how players reacted to griefing; • the impact to the well-being of the players after a griefing incident. The thesis concluded with advice to MMORPG developers regarding the most pervasive, frequent and impactful types of griefing, and how game design may increase or decrease the amount and intensity of griefing.
- Description: Doctor of Philosophy
- Authors: Achterbosch, Leigh
- Date: 2015
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis presents findings from research into the global phenomenon known as griefing that occurs in Massively Multiplayer Online Role-Playing Games (MMORPGs). Griefing, in its simplest terms, refers to the act of one player intentionally disrupting another player’s game experience for personal pleasure and potential gain. For too long it has been unknown how pervasive griefing is, how frequently griefing occurs and, in particular, the impact on players that are subjected to griefing. There has also been limited research regarding what causes a player to perform griefing. This thesis addresses these concerns by answering the research question “What are the causes and implications of griefing in Massively Multiplayer Online Role-Playing Games, and what magnitude of griefing exists in this genre?” Mixed method research was employed using the “Sequential Explanatory Strategy”, in which a quantitative phase was followed by a qualitative phase to strengthen the findings. The quantitative phase consisted of a survey that attracted 1188 participants of a representative player population. The qualitative phase consisted of interviews with 15 participants to give more personalised data. The data was analysed from the perspectives of different demographics and different associations to griefing. The thesis contributed original findings regarding the causes, magnitude and implications of griefing in MMORPGs. Some of the main findings were: • Factors that motivated a player to cause grief; • how griefers selected their targets based on particular demographics or avatar characteristics; • the pervasiveness, frequency and impact of different types of griefing; • the amount of griefing that can be tolerated; • how players reacted to griefing; • the impact to the well-being of the players after a griefing incident. The thesis concluded with advice to MMORPG developers regarding the most pervasive, frequent and impactful types of griefing, and how game design may increase or decrease the amount and intensity of griefing.
- Description: Doctor of Philosophy
Challenges faced by early-career researchers in the sciences in Australia and the consequent effect of those challenges on their careers : a mixed methods project
- Authors: Christian, Katherine
- Date: 2021
- Type: Text , Thesis , PhD
- Full Text:
- Description: The purpose of the study was to explore the challenges faced by early-career researchers (ECRs) in the sciences in Australia and the consequent effect of those challenges on their careers. Using a realist/postpositivist paradigm, an evaluative approach, and a framework of job satisfaction, this project has explored and compared the views of ECRs to evaluate the factors which shape the ECR experience and contribute to job satisfaction or dissatisfaction and intention to leave, and to define the features which are necessary to keep an ECR in research. Data collection for this mixed methods study entailed a national survey of researchers working in universities and research institutes (n=658), a focus group discussion and semistructured in-depth interviews with eight women from a variety of scientific disciplines who had recently left academic research workplaces. I focussed particularly on the difficulties consequent to job insecurity: the constant need to attracting funding and a permanent position, lack of work-life balance and associated stress; and evidence of workplace difficulties such as bullying, harassment or inequity and support – or lack of it – offered by the research institutions. I examined the factors which contribute to and barriers which prevent job satisfaction of this population, and the consequent intention (if any) for ECRs to leave research or change their career path. I found an interesting situation whereby the satisfaction derived from a “love of science” was counterbalanced by stress and poor working conditions which are a consequence of lack of job security, typified by poor supervision, bullying or harassment, inequitable hiring practices, a concerning rate of impact from “questionable research practices” (impacting 34%-41% of respondents) and evidence of very high (80%) intention of ECRs to leave their position. The most significant predictor of intention to leave is time as a postdoctoral scientist: eventually the job insecurity and its associated stresses become too much and the ECRs leave their chosen career for work elsewhere. This decision, too, provides interesting findings as many of the ECRs have difficulty planning what to do next. They feel ill-prepared for an alternate career and suffer from a sense of failure as a result of having to leave academia. While addressing the shortage of funding is outside the scope of this study, in addition to offering my findings I put forward a range of recommendations which could lead to ar change of culture and benefit the wellbeing of ECRs in STEMM without incurring significant cost. The Australian Government, higher education institutions and the research community need to improve job security and workplace conditions and take better care of our people in STEMM disciplines or we will not have the scientists we need to deliver the “innovative Australia” planned for 2030 (Department of Industry Innovation and Science, 2018)
- Description: Doctor of Philosophy
- Authors: Christian, Katherine
- Date: 2021
- Type: Text , Thesis , PhD
- Full Text:
- Description: The purpose of the study was to explore the challenges faced by early-career researchers (ECRs) in the sciences in Australia and the consequent effect of those challenges on their careers. Using a realist/postpositivist paradigm, an evaluative approach, and a framework of job satisfaction, this project has explored and compared the views of ECRs to evaluate the factors which shape the ECR experience and contribute to job satisfaction or dissatisfaction and intention to leave, and to define the features which are necessary to keep an ECR in research. Data collection for this mixed methods study entailed a national survey of researchers working in universities and research institutes (n=658), a focus group discussion and semistructured in-depth interviews with eight women from a variety of scientific disciplines who had recently left academic research workplaces. I focussed particularly on the difficulties consequent to job insecurity: the constant need to attracting funding and a permanent position, lack of work-life balance and associated stress; and evidence of workplace difficulties such as bullying, harassment or inequity and support – or lack of it – offered by the research institutions. I examined the factors which contribute to and barriers which prevent job satisfaction of this population, and the consequent intention (if any) for ECRs to leave research or change their career path. I found an interesting situation whereby the satisfaction derived from a “love of science” was counterbalanced by stress and poor working conditions which are a consequence of lack of job security, typified by poor supervision, bullying or harassment, inequitable hiring practices, a concerning rate of impact from “questionable research practices” (impacting 34%-41% of respondents) and evidence of very high (80%) intention of ECRs to leave their position. The most significant predictor of intention to leave is time as a postdoctoral scientist: eventually the job insecurity and its associated stresses become too much and the ECRs leave their chosen career for work elsewhere. This decision, too, provides interesting findings as many of the ECRs have difficulty planning what to do next. They feel ill-prepared for an alternate career and suffer from a sense of failure as a result of having to leave academia. While addressing the shortage of funding is outside the scope of this study, in addition to offering my findings I put forward a range of recommendations which could lead to ar change of culture and benefit the wellbeing of ECRs in STEMM without incurring significant cost. The Australian Government, higher education institutions and the research community need to improve job security and workplace conditions and take better care of our people in STEMM disciplines or we will not have the scientists we need to deliver the “innovative Australia” planned for 2030 (Department of Industry Innovation and Science, 2018)
- Description: Doctor of Philosophy
Changing rural general practitioner practice : Evaluating health assessment uptake
- Authors: McGrath, Alicia
- Date: 2003
- Type: Text , Thesis , Masters
- Full Text:
- Description: The Enhanced Primary Care Package aimed to improve health and quality of life through enhancing primary health care for those over 75 years, Aboriginal and Torres Strait Islanders over 55 years and those with chronic conditions and multidisciplinary needs. A multi-level approach was implemented to promote the package. West Vic Division of General Practice conducted the General Practice Education Support and Community Linkages implementation program for the package in Western Victoria and focused on health assessments for those over 75 years. This research investigated what factors affected change in rural general practitioner practice through surveying general practitioners and collecting Health Insurance Commission data prior to and following the program. Patients were also interviewed to determine acceptance of health assessments and nurse involvement. The program increased awareness, but had little effect on increasing uptake, as only 53% of general practitioners began undertaking health assessments. However the general practitioners indicated an increased frequency of health assessment prescription. Health Insurance Commission data suggested an immediate increase in the use of the assessments, however the rate fluctuated and then declined. Lack of sustained uptake of the program was not associated with remuneration, as 77% of general practitioners did not regard finance as a barrier. Respondents’ major barrier was time (40% pre-education, 73% post-education). This data reflected a rural environment where general practitioners face competing priorities, time constraints, workforce shortage and long consultation lists. A notable change did however occur from practice nurse employment as the involvement of a practice nurse generally resulted in patient satisfaction with the assessment. It was apparent that a complex multifaceted and longer-term view is needed to address factors which limit rural general practitioners’ ability to change. This needs to be addressed at the Commonwealth level and not in isolation in order to produce an integrated framework to enhance and promote, rather than demand change.
- Description: Master of Applied Science
- Authors: McGrath, Alicia
- Date: 2003
- Type: Text , Thesis , Masters
- Full Text:
- Description: The Enhanced Primary Care Package aimed to improve health and quality of life through enhancing primary health care for those over 75 years, Aboriginal and Torres Strait Islanders over 55 years and those with chronic conditions and multidisciplinary needs. A multi-level approach was implemented to promote the package. West Vic Division of General Practice conducted the General Practice Education Support and Community Linkages implementation program for the package in Western Victoria and focused on health assessments for those over 75 years. This research investigated what factors affected change in rural general practitioner practice through surveying general practitioners and collecting Health Insurance Commission data prior to and following the program. Patients were also interviewed to determine acceptance of health assessments and nurse involvement. The program increased awareness, but had little effect on increasing uptake, as only 53% of general practitioners began undertaking health assessments. However the general practitioners indicated an increased frequency of health assessment prescription. Health Insurance Commission data suggested an immediate increase in the use of the assessments, however the rate fluctuated and then declined. Lack of sustained uptake of the program was not associated with remuneration, as 77% of general practitioners did not regard finance as a barrier. Respondents’ major barrier was time (40% pre-education, 73% post-education). This data reflected a rural environment where general practitioners face competing priorities, time constraints, workforce shortage and long consultation lists. A notable change did however occur from practice nurse employment as the involvement of a practice nurse generally resulted in patient satisfaction with the assessment. It was apparent that a complex multifaceted and longer-term view is needed to address factors which limit rural general practitioners’ ability to change. This needs to be addressed at the Commonwealth level and not in isolation in order to produce an integrated framework to enhance and promote, rather than demand change.
- Description: Master of Applied Science
Characterisation of apoptosis in thye1M6
- Authors: Hay, Stewart
- Date: 2003
- Type: Text , Thesis , PhD
- Full Text:
- Description: "Interest surrounds apoptosis-inducing factors for use in treatment of proliferative disorders and for the elucidation of cell death pathways. Here, a murine SCID thymic lymphoma cell line (ThyE1M6) is described which produces a cytotoxic factor that acts on specific human and murine cancer cell lines, including some lymphomas and hepatomas. The cytotoxic property of the lymphoma was first noted in co-culture experiments that revealed increased apoptosis in some cell types. This attribute was thought to be unusual and as a result a project was initiated with the aim to characterise the factor responsible for cell death."
- Description: Doctor of Philosophy
- Authors: Hay, Stewart
- Date: 2003
- Type: Text , Thesis , PhD
- Full Text:
- Description: "Interest surrounds apoptosis-inducing factors for use in treatment of proliferative disorders and for the elucidation of cell death pathways. Here, a murine SCID thymic lymphoma cell line (ThyE1M6) is described which produces a cytotoxic factor that acts on specific human and murine cancer cell lines, including some lymphomas and hepatomas. The cytotoxic property of the lymphoma was first noted in co-culture experiments that revealed increased apoptosis in some cell types. This attribute was thought to be unusual and as a result a project was initiated with the aim to characterise the factor responsible for cell death."
- Description: Doctor of Philosophy
Characterisation of the deformation behaviour of unbound granular materials using repeated load triaxial testing
- Authors: Zhalehjoo, Negin
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Unbound Granular Materials (UGMs) are used in the base/subbase layers of flexible pavements for the majority of roads around the world. The deterioration of pavements increases with the increase of traffic loadings. To ensure the long-term performance and serviceability of pavement structures through a realistic design, the precise evaluation and comprehensive characterisation of the resilient and permanent deformation behaviour of pavement materials are essential. The present PhD study aims to investigate the characterisation of the resilient and permanent deformation behaviour of four road base UGMs sourced from quarries in Victoria, Australia, using Repeated Load Triaxial (RLT) testing. The triaxial system used in this study is instrumented with four axial deformation measurement transducers to achieve highly precise measurements and to evaluate the effect of instrumentation on the resilient modulus of UGMs. The resilient Poisson’s ratio of the studied UGMs is also determined using a radial Hall-Effect transducer. Moreover, a series of permanent deformation tests is performed to precisely characterise the axial and radial permanent deformation behaviour of UGMs and investigate the factors that may significantly influence the accumulated axial and radial permanent deformations. Finally, three permanent deformation models incorporated with a time-hardening procedure are employed to predict the magnitude of permanent strain for multiple stress levels of the RLT test. The predictions using the employed models are then compared against the measured values to evaluate the suitability of the models and to identify the model that best predicts the strain accumulation behaviour of the tested UGMs. While this study focuses on the resilient and permanent deformation behaviour of four Victorian UGMs under repeated loading, the knowledge generated from this comprehensive investigation will contribute towards the global development of more reliable methods for evaluating the long-term performance of pavement structures and minimising road maintenance and repair costs.
- Description: Doctor of Philosophy
- Authors: Zhalehjoo, Negin
- Date: 2018
- Type: Text , Thesis , PhD
- Full Text:
- Description: Unbound Granular Materials (UGMs) are used in the base/subbase layers of flexible pavements for the majority of roads around the world. The deterioration of pavements increases with the increase of traffic loadings. To ensure the long-term performance and serviceability of pavement structures through a realistic design, the precise evaluation and comprehensive characterisation of the resilient and permanent deformation behaviour of pavement materials are essential. The present PhD study aims to investigate the characterisation of the resilient and permanent deformation behaviour of four road base UGMs sourced from quarries in Victoria, Australia, using Repeated Load Triaxial (RLT) testing. The triaxial system used in this study is instrumented with four axial deformation measurement transducers to achieve highly precise measurements and to evaluate the effect of instrumentation on the resilient modulus of UGMs. The resilient Poisson’s ratio of the studied UGMs is also determined using a radial Hall-Effect transducer. Moreover, a series of permanent deformation tests is performed to precisely characterise the axial and radial permanent deformation behaviour of UGMs and investigate the factors that may significantly influence the accumulated axial and radial permanent deformations. Finally, three permanent deformation models incorporated with a time-hardening procedure are employed to predict the magnitude of permanent strain for multiple stress levels of the RLT test. The predictions using the employed models are then compared against the measured values to evaluate the suitability of the models and to identify the model that best predicts the strain accumulation behaviour of the tested UGMs. While this study focuses on the resilient and permanent deformation behaviour of four Victorian UGMs under repeated loading, the knowledge generated from this comprehensive investigation will contribute towards the global development of more reliable methods for evaluating the long-term performance of pavement structures and minimising road maintenance and repair costs.
- Description: Doctor of Philosophy
Characterising MAIT cells in human mucosal cancers
- Authors: Kelly, Jason
- Date: 2021
- Type: Text , Thesis , PhD
- Full Text:
- Description: Mucosal associated invariant T cells (MAIT cells) are MR1-restricted T cells that regulate the local immune milieu with cytotoxic and cytokine responses. MAIT cells are well-known for their antimicrobial properties but are also of interest in mucosal cancers, such as colorectal cancer (CRC) and lung cancer (LC). These cancers arise in tissues that provide a barrier to the gut-resident microbiota that can potentially stimulate MAIT cells. Previous studies established that MAIT cells are present within CRC tissues, but there has been contradictory evidence about their significance within these tumour tissues. For example, their cytokine response may promote tumour elimination; however, the high frequencies of MAIT cells within CRC correlate with poor prognostic outcomes, suggesting they may be detrimental in these cancers. Despite the interest in MAIT cells within these tumours, little is known about their location, activation status and cytokine potential within the neoplastic tissue. Chapter 1 of this project investigated human circulating MAIT cells in both CRC and LC patients, finding a significant reduction in the frequency of circulating MAIT cells in the LC patient cohort. We also investigated the frequency and location of MAIT cells within non-cancerous colorectal tissues, identifying that MAIT cells are frequent in the sub-epithelial dome of gut-associated lymphoid tissue (GALT). In contrast, MAIT cells are frequent in the inflammatory response at the tumour margin in CRC tissues. Chapter 2 of this project investigated MAIT cell activation within the CRC tumour environment, with CD25 analysis identifying that MAIT cells appeared to be selectively activated within CRC tissue. We then sought to identify which cells within CRC tissue can present the cognate MAIT cell antigen, finding that CRC cells can take up soluble antigen, upregulate MR1 to the cell surface, and activate MAIT cells. However, these experiments identified a yet to be characterised soluble product secreted by CRC cells that appears to suppress MAIT cell TNF expression after encountering antigen. Chapter 3 of this project investigated MAIT cell responses after chronic (> 2 weeks) stimulation via TCR signalling, a condition likely to be found in both CRC tissue and pre-cancerous lesions, as these lesions are associated with mucosal barrier defects that allow microbes within the gut lumen to transit the barrier. These investigations found a novel, mixed Th1/Th2 cytokine response that included prodigious IL-13 expression. We found that the IL-13 produced by chronically stimulated MAIT cells was sufficient to signal to CRC cells and induce CRC cell transcriptional changes via the STAT6 pathway. Collectively, the findings of our study have provided new insights about the significance of MAIT cells in CRC and highlighted them as a potential target for immunotherapies to improve anti-tumour immunity in mucosal tissues.
- Description: Doctor of Philosophy
- Authors: Kelly, Jason
- Date: 2021
- Type: Text , Thesis , PhD
- Full Text:
- Description: Mucosal associated invariant T cells (MAIT cells) are MR1-restricted T cells that regulate the local immune milieu with cytotoxic and cytokine responses. MAIT cells are well-known for their antimicrobial properties but are also of interest in mucosal cancers, such as colorectal cancer (CRC) and lung cancer (LC). These cancers arise in tissues that provide a barrier to the gut-resident microbiota that can potentially stimulate MAIT cells. Previous studies established that MAIT cells are present within CRC tissues, but there has been contradictory evidence about their significance within these tumour tissues. For example, their cytokine response may promote tumour elimination; however, the high frequencies of MAIT cells within CRC correlate with poor prognostic outcomes, suggesting they may be detrimental in these cancers. Despite the interest in MAIT cells within these tumours, little is known about their location, activation status and cytokine potential within the neoplastic tissue. Chapter 1 of this project investigated human circulating MAIT cells in both CRC and LC patients, finding a significant reduction in the frequency of circulating MAIT cells in the LC patient cohort. We also investigated the frequency and location of MAIT cells within non-cancerous colorectal tissues, identifying that MAIT cells are frequent in the sub-epithelial dome of gut-associated lymphoid tissue (GALT). In contrast, MAIT cells are frequent in the inflammatory response at the tumour margin in CRC tissues. Chapter 2 of this project investigated MAIT cell activation within the CRC tumour environment, with CD25 analysis identifying that MAIT cells appeared to be selectively activated within CRC tissue. We then sought to identify which cells within CRC tissue can present the cognate MAIT cell antigen, finding that CRC cells can take up soluble antigen, upregulate MR1 to the cell surface, and activate MAIT cells. However, these experiments identified a yet to be characterised soluble product secreted by CRC cells that appears to suppress MAIT cell TNF expression after encountering antigen. Chapter 3 of this project investigated MAIT cell responses after chronic (> 2 weeks) stimulation via TCR signalling, a condition likely to be found in both CRC tissue and pre-cancerous lesions, as these lesions are associated with mucosal barrier defects that allow microbes within the gut lumen to transit the barrier. These investigations found a novel, mixed Th1/Th2 cytokine response that included prodigious IL-13 expression. We found that the IL-13 produced by chronically stimulated MAIT cells was sufficient to signal to CRC cells and induce CRC cell transcriptional changes via the STAT6 pathway. Collectively, the findings of our study have provided new insights about the significance of MAIT cells in CRC and highlighted them as a potential target for immunotherapies to improve anti-tumour immunity in mucosal tissues.
- Description: Doctor of Philosophy
Characteristics of the female landing pattern
- Authors: Saunders, Natalie
- Date: 2006
- Type: Text , Thesis , PhD
- Full Text:
- Description: "This research aimed to explore and better understand intervention protocols and their effect on lower limb control associated with anterior cruciate ligament (ACL) injury. A fundamental and unique aspect of this investigation was to establish a lab-based testing protocol that successfully mimicked actual game play. [...]This research validated a lab-based measure that best mimicked game-play to use as a pre- and post- testing measure for two common methods used in current ACL intervention strategies. In addition, further understanding of the effects of a landing training and dynamic balance training program were found."
- Description: Doctor of Philosphy
- Authors: Saunders, Natalie
- Date: 2006
- Type: Text , Thesis , PhD
- Full Text:
- Description: "This research aimed to explore and better understand intervention protocols and their effect on lower limb control associated with anterior cruciate ligament (ACL) injury. A fundamental and unique aspect of this investigation was to establish a lab-based testing protocol that successfully mimicked actual game play. [...]This research validated a lab-based measure that best mimicked game-play to use as a pre- and post- testing measure for two common methods used in current ACL intervention strategies. In addition, further understanding of the effects of a landing training and dynamic balance training program were found."
- Description: Doctor of Philosphy
Charting cyberspace : self-identity, community, and nationalism in the virtual realm
- Authors: Thompson, Kevin
- Date: 2003
- Type: Text , Thesis , Masters
- Full Text:
- Description: "This thesis takes a broad look at recent developments in cyberspace with a particular focus on the key concept areas of self-identity, community and nationalism. The field of cyber research is very much a nascent one, but already a seminal core of literature abounds that privleges cyberspace as a world that is somehow removed from the everday one in which we reside. This study argues against this assertion, suggesting instead that cyberspace, for most users, is merely another commonly accessed part of daily life."
- Description: Doctor of Philosophy
- Authors: Thompson, Kevin
- Date: 2003
- Type: Text , Thesis , Masters
- Full Text:
- Description: "This thesis takes a broad look at recent developments in cyberspace with a particular focus on the key concept areas of self-identity, community and nationalism. The field of cyber research is very much a nascent one, but already a seminal core of literature abounds that privleges cyberspace as a world that is somehow removed from the everday one in which we reside. This study argues against this assertion, suggesting instead that cyberspace, for most users, is merely another commonly accessed part of daily life."
- Description: Doctor of Philosophy
Chemical management in research laboratories : South-Eastern Australia, 1997
- Authors: Bailey, Trevor
- Date: 1997
- Type: Text , Thesis , Masters
- Full Text: false
- Description: "Through a comprehensive literature review this project examines the necessary components of a laboratory chemical safety program, including requirements under the new hazardous substance regulations. It also examines, via a survey, the problems associated with the laboratory use of chemicals and with compliance with the new regulations. Finally the current situation in Australia and the approach research laboratories must take in the future to achieve compliance with the new regulatory package are reviewed."
- Description: Master of Applied Science
- Authors: Bailey, Trevor
- Date: 1997
- Type: Text , Thesis , Masters
- Full Text: false
- Description: "Through a comprehensive literature review this project examines the necessary components of a laboratory chemical safety program, including requirements under the new hazardous substance regulations. It also examines, via a survey, the problems associated with the laboratory use of chemicals and with compliance with the new regulations. Finally the current situation in Australia and the approach research laboratories must take in the future to achieve compliance with the new regulatory package are reviewed."
- Description: Master of Applied Science
Chemistry of bis(O-ethyldithiocarbonato)cadmium(II) and flotation properties of aminodithiocarbonates
- Authors: Griffiths, Philip
- Date: 1976
- Type: Text , Thesis , Masters
- Full Text: false
- Description: Masters of Applied Science
- Authors: Griffiths, Philip
- Date: 1976
- Type: Text , Thesis , Masters
- Full Text: false
- Description: Masters of Applied Science