On connectivity of wireless sensor networks with directional antennas
- Wang, Qiu, Dai, Hong-Ning, Zheng, Zibin, Imran, Muhammad, Vasilakos, Athanasios
- Authors: Wang, Qiu , Dai, Hong-Ning , Zheng, Zibin , Imran, Muhammad , Vasilakos, Athanasios
- Date: 2017
- Type: Text , Journal article
- Relation: Sensors (Switzerland) Vol. 17, no. 1 (2017), p.
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- Description: In this paper, we investigate the network connectivity of wireless sensor networks with directional antennas. In particular, we establish a general framework to analyze the network connectivity while considering various antenna models and the channel randomness. Since existing directional antenna models have their pros and cons in the accuracy of reflecting realistic antennas and the computational complexity, we propose a new analytical directional antenna model called the iris model to balance the accuracy against the complexity. We conduct extensive simulations to evaluate the analytical framework. Our results show that our proposed analytical model on the network connectivity is accurate, and our iris antenna model can provide a better approximation to realistic directional antennas than other existing antenna models. © 2017 by the authors; licensee MDPI, Basel, Switzerland.
- Authors: Wang, Qiu , Dai, Hong-Ning , Zheng, Zibin , Imran, Muhammad , Vasilakos, Athanasios
- Date: 2017
- Type: Text , Journal article
- Relation: Sensors (Switzerland) Vol. 17, no. 1 (2017), p.
- Full Text:
- Reviewed:
- Description: In this paper, we investigate the network connectivity of wireless sensor networks with directional antennas. In particular, we establish a general framework to analyze the network connectivity while considering various antenna models and the channel randomness. Since existing directional antenna models have their pros and cons in the accuracy of reflecting realistic antennas and the computational complexity, we propose a new analytical directional antenna model called the iris model to balance the accuracy against the complexity. We conduct extensive simulations to evaluate the analytical framework. Our results show that our proposed analytical model on the network connectivity is accurate, and our iris antenna model can provide a better approximation to realistic directional antennas than other existing antenna models. © 2017 by the authors; licensee MDPI, Basel, Switzerland.
On modeling and global solutions for d.c. optimization problems by canonical duality theory
- Authors: Jin, Zhong , Gao, David
- Date: 2017
- Type: Text , Journal article
- Relation: Applied Mathematics and Computation Vol. 296, no. (2017), p. 168-181
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- Description: This paper presents a canonical d.c. (difference of canonical and convex functions) programming problem, which can be used to model general global optimization problems in complex systems. It shows that by using the canonical duality theory, a large class of nonconvex minimization problems can be equivalently converted to a unified concave maximization problem over a convex domain, which can be solved easily under certain conditions. Additionally, a detailed proof for triality theory is provided, which can be used to identify local extremal solutions. Applications are illustrated and open problems are presented.
- Description: This paper presents a canonical d.c. (difference of canonical and convex functions) programming problem, which can be used to model general global optimization problems in complex systems. It shows that by using the canonical duality theory, a large class of nonconvex minimization problems can be equivalently converted to a unified concave maximization problem over a convex domain, which can be solved easily under certain conditions. Additionally, a detailed proof for triality theory is provided, which can be used to identify local extremal solutions. Applications are illustrated and open problems are presented. © 2016 Elsevier Inc.
- Authors: Jin, Zhong , Gao, David
- Date: 2017
- Type: Text , Journal article
- Relation: Applied Mathematics and Computation Vol. 296, no. (2017), p. 168-181
- Full Text:
- Reviewed:
- Description: This paper presents a canonical d.c. (difference of canonical and convex functions) programming problem, which can be used to model general global optimization problems in complex systems. It shows that by using the canonical duality theory, a large class of nonconvex minimization problems can be equivalently converted to a unified concave maximization problem over a convex domain, which can be solved easily under certain conditions. Additionally, a detailed proof for triality theory is provided, which can be used to identify local extremal solutions. Applications are illustrated and open problems are presented.
- Description: This paper presents a canonical d.c. (difference of canonical and convex functions) programming problem, which can be used to model general global optimization problems in complex systems. It shows that by using the canonical duality theory, a large class of nonconvex minimization problems can be equivalently converted to a unified concave maximization problem over a convex domain, which can be solved easily under certain conditions. Additionally, a detailed proof for triality theory is provided, which can be used to identify local extremal solutions. Applications are illustrated and open problems are presented. © 2016 Elsevier Inc.
On the Aubin property of a class of parameterized variational systems
- Gfrerer, Helmut, Outrata, Jiri
- Authors: Gfrerer, Helmut , Outrata, Jiri
- Date: 2017
- Type: Text , Journal article
- Relation: Mathematical Methods of Operations Research Vol. 86, no. 3 (2017), p. 443-467
- Relation: http://purl.org/au-research/grants/arc/DP160100854
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- Description: The paper deals with a new sharp condition ensuring the Aubin property of solution maps to a class of parameterized variational systems. This class encompasses various types of parameterized variational inequalities/generalized equations with fairly general constraint sets. The new condition requires computation of directional limiting coderivatives of the normal-cone mapping for the so-called critical directions. The respective formulas have the form of a second-order chain rule and extend the available calculus of directional limiting objects. The suggested procedure is illustrated by means of examples. © 2017, Springer-Verlag GmbH Germany.
- Authors: Gfrerer, Helmut , Outrata, Jiri
- Date: 2017
- Type: Text , Journal article
- Relation: Mathematical Methods of Operations Research Vol. 86, no. 3 (2017), p. 443-467
- Relation: http://purl.org/au-research/grants/arc/DP160100854
- Full Text:
- Reviewed:
- Description: The paper deals with a new sharp condition ensuring the Aubin property of solution maps to a class of parameterized variational systems. This class encompasses various types of parameterized variational inequalities/generalized equations with fairly general constraint sets. The new condition requires computation of directional limiting coderivatives of the normal-cone mapping for the so-called critical directions. The respective formulas have the form of a second-order chain rule and extend the available calculus of directional limiting objects. The suggested procedure is illustrated by means of examples. © 2017, Springer-Verlag GmbH Germany.
On the convexity of nonlinear elastic energies in the right Cauchy-Green tensor
- Gao, David, Neff, Patrizio, Roventa, Ionel, Thiel, Christian
- Authors: Gao, David , Neff, Patrizio , Roventa, Ionel , Thiel, Christian
- Date: 2017
- Type: Text , Journal article
- Relation: Journal of Elasticity Vol. 127, no. 2 (2017), p. 303-308
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- Description: We present a sufficient condition under which a weak solution of the Euler-Lagrange equations in nonlinear elasticity is already a global minimizer of the corresponding elastic energy functional. This criterion is applicable to energies which are convex with respect to the right Cauchy-Green tensor , where denotes the gradient of deformation. Examples of such energies exhibiting a blow up for are given.
- Authors: Gao, David , Neff, Patrizio , Roventa, Ionel , Thiel, Christian
- Date: 2017
- Type: Text , Journal article
- Relation: Journal of Elasticity Vol. 127, no. 2 (2017), p. 303-308
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- Description: We present a sufficient condition under which a weak solution of the Euler-Lagrange equations in nonlinear elasticity is already a global minimizer of the corresponding elastic energy functional. This criterion is applicable to energies which are convex with respect to the right Cauchy-Green tensor , where denotes the gradient of deformation. Examples of such energies exhibiting a blow up for are given.
One session of high-intensity interval training (HIIT) every 5 days, improves muscle power but not static balance in lifelong sedentary ageing men : A randomized controlled trial
- Sculthorpe, Nicholas, Herbert, Peter, Grace, Fergal
- Authors: Sculthorpe, Nicholas , Herbert, Peter , Grace, Fergal
- Date: 2017
- Type: Text , Journal article
- Relation: Medicine (United States) Vol. 96, no. 6 (2017), p. 1-8
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- Description: Background: Declining muscle power during advancing age predicts falls and loss of independence. High-intensity interval training (HIIT) may improve muscle power, but remains largely unstudied in ageing participants. Methods: This randomized controlled trial (RCT) investigated the efficacy of a low-frequency HIIT (LfHIIT) intervention on peak muscle power (peak power output [PPO]), body composition, and balance in lifelong sedentary but otherwise healthy males. Methods: Thirty-Three lifelong sedentary ageing men were randomly assigned to either intervention (INT; n=22, age 62.3±4.1 years) or control (n=11, age 61.6±5.0 years) who were both assessed at 3 distinct measurement points (phase A), after 6 weeks of conditioning exercise (phase B), and after 6 weeks of HIIT once every 5 days in INT (phase C), where control remained inactive throughout the study. Results: Static balance remained unaffected, and both absolute and relative PPO were not different between groups at phases A or B, but increased significantly in INT after LfHIIT (P<0.01). Lean body mass displayed a significant interaction (P<0.01) due to an increase in INT between phases B and C (P<0.05). Conclusions: 6 weeks of LfHIIT exercise feasible and effective method to induce clinically relevant improvements in absolute and relative PPO, but does not improve static balance in sedentary ageing men. Abbreviations: ACSM = American College of Sports Medicine, CON = control group, GP = general medical practitioner, HIIT = high-intensity interval training, HRR = heart rate reserve, INT = intervention group, LfHIIT = low-frequency high-intensity interval training, PAR-Q = Physical Activity Readiness Questionnaire, PPO = peak power output, rPPO = relative peak power output, rPPOFFM = rPPO relative to fat free mass, VO2 max = maximal oxygen uptake. © 2017 the Author(s).
- Authors: Sculthorpe, Nicholas , Herbert, Peter , Grace, Fergal
- Date: 2017
- Type: Text , Journal article
- Relation: Medicine (United States) Vol. 96, no. 6 (2017), p. 1-8
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- Description: Background: Declining muscle power during advancing age predicts falls and loss of independence. High-intensity interval training (HIIT) may improve muscle power, but remains largely unstudied in ageing participants. Methods: This randomized controlled trial (RCT) investigated the efficacy of a low-frequency HIIT (LfHIIT) intervention on peak muscle power (peak power output [PPO]), body composition, and balance in lifelong sedentary but otherwise healthy males. Methods: Thirty-Three lifelong sedentary ageing men were randomly assigned to either intervention (INT; n=22, age 62.3±4.1 years) or control (n=11, age 61.6±5.0 years) who were both assessed at 3 distinct measurement points (phase A), after 6 weeks of conditioning exercise (phase B), and after 6 weeks of HIIT once every 5 days in INT (phase C), where control remained inactive throughout the study. Results: Static balance remained unaffected, and both absolute and relative PPO were not different between groups at phases A or B, but increased significantly in INT after LfHIIT (P<0.01). Lean body mass displayed a significant interaction (P<0.01) due to an increase in INT between phases B and C (P<0.05). Conclusions: 6 weeks of LfHIIT exercise feasible and effective method to induce clinically relevant improvements in absolute and relative PPO, but does not improve static balance in sedentary ageing men. Abbreviations: ACSM = American College of Sports Medicine, CON = control group, GP = general medical practitioner, HIIT = high-intensity interval training, HRR = heart rate reserve, INT = intervention group, LfHIIT = low-frequency high-intensity interval training, PAR-Q = Physical Activity Readiness Questionnaire, PPO = peak power output, rPPO = relative peak power output, rPPOFFM = rPPO relative to fat free mass, VO2 max = maximal oxygen uptake. © 2017 the Author(s).
Online transformer internal fault detection based on instantaneous voltage and current measurements considering impact of harmonics
- Masoum, Ali, Hashemnia, Seyednaser, Abu-Siada, Ahmed, Masoum, Mohammad Sherkat, Islam, Syed
- Authors: Masoum, Ali , Hashemnia, Seyednaser , Abu-Siada, Ahmed , Masoum, Mohammad Sherkat , Islam, Syed
- Date: 2017
- Type: Text , Journal article
- Relation: IEEE Transactions on Power Delivery Vol. 32, no. 2 (2017), p. 587-598
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- Description: This paper investigates the performance of a recently proposed online transformer internal fault detection technique and examines impact of harmonics through detailed nonlinear simulation of a transformer using three-dimensional finite element modelling. The proposed online technique is based on considering the correlation between the instantaneous input and output voltage difference (ΔV) and the input current of a particular phase as a finger print of the transformer that could be measured every cycle to identify any incipient mechanical deformation within power transformers. To precisely emulate real transformer operation under various winding mechanical deformations, a detailed three-dimensional finite-element model is developed. Detailed simulations with (non)sinusoidal excitation are performed and analysed to demonstrate the unique impact of each fault on the ΔV-I locus. Impact of harmonic order, magnitude and phase angle is also investigated. Furthermore, practical measurements have been performed to validate the effect of winding short circuit fault on the proposed ΔV-I locus without and with the impact of system harmonics.
- Authors: Masoum, Ali , Hashemnia, Seyednaser , Abu-Siada, Ahmed , Masoum, Mohammad Sherkat , Islam, Syed
- Date: 2017
- Type: Text , Journal article
- Relation: IEEE Transactions on Power Delivery Vol. 32, no. 2 (2017), p. 587-598
- Full Text:
- Reviewed:
- Description: This paper investigates the performance of a recently proposed online transformer internal fault detection technique and examines impact of harmonics through detailed nonlinear simulation of a transformer using three-dimensional finite element modelling. The proposed online technique is based on considering the correlation between the instantaneous input and output voltage difference (ΔV) and the input current of a particular phase as a finger print of the transformer that could be measured every cycle to identify any incipient mechanical deformation within power transformers. To precisely emulate real transformer operation under various winding mechanical deformations, a detailed three-dimensional finite-element model is developed. Detailed simulations with (non)sinusoidal excitation are performed and analysed to demonstrate the unique impact of each fault on the ΔV-I locus. Impact of harmonic order, magnitude and phase angle is also investigated. Furthermore, practical measurements have been performed to validate the effect of winding short circuit fault on the proposed ΔV-I locus without and with the impact of system harmonics.
Optimal taxonomic groups for biodiversity assessment: a meta-analytic approach
- Westgate, Martin, Tulloch, Ayesha, Barton, Philip, Pierson, Jennifer, Lindenmayer, David
- Authors: Westgate, Martin , Tulloch, Ayesha , Barton, Philip , Pierson, Jennifer , Lindenmayer, David
- Date: 2017
- Type: Text , Journal article
- Relation: Ecography Vol. 40, no. 4 (2017), p. 539-548
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- Description: A fundamental decision in biodiversity assessment is the selection of one or more study taxa, a choice that is often made using qualitative criteria such as historical precedent, ease of detection, or available technical or taxonomic expertise. A more robust approach would involve selecting taxa based on the a priori expectation that they will provide the best possible information on unmeasured groups, but data to inform such hypotheses are often lacking. Using a global meta-analysis, we quantified the proportion of variability that each of 12 taxonomic groups (at the Order level or above) explained in the richness or composition of other taxa. We then applied optimization to matrices of pairwise congruency to identify the best set of complementary surrogate groups. We found that no single taxon was an optimal surrogate for both the richness and composition of unmeasured taxa if we used simple methods to aggregate congruence data between studies. In contrast, statistical methods that accounted for well-known drivers of cross-taxon congruence (spatial extent, grain size, and latitude) lead to the prioritization of similar surrogates for both species richness and composition. Advanced statistical methods were also more effective at describing known ecological relationships between taxa than simple methods, and show that congruence is typically highest between taxonomically and functionally dissimilar taxa. Birds and vascular plants were most frequently selected by our algorithm as surrogates for other taxonomic groups, but the extent to which any one taxon was the ‘optimal’ choice of surrogate for other biodiversity was highly context-dependent. In the absence of other information – such as in data-poor areas of the globe, and under limited budgets for monitoring or assessment – ecologists can use our results to assess which taxa are most likely to reflect the distribution of the richness or composition of ‘total’ biodiversity. © 2016 The Authors
- Authors: Westgate, Martin , Tulloch, Ayesha , Barton, Philip , Pierson, Jennifer , Lindenmayer, David
- Date: 2017
- Type: Text , Journal article
- Relation: Ecography Vol. 40, no. 4 (2017), p. 539-548
- Full Text:
- Reviewed:
- Description: A fundamental decision in biodiversity assessment is the selection of one or more study taxa, a choice that is often made using qualitative criteria such as historical precedent, ease of detection, or available technical or taxonomic expertise. A more robust approach would involve selecting taxa based on the a priori expectation that they will provide the best possible information on unmeasured groups, but data to inform such hypotheses are often lacking. Using a global meta-analysis, we quantified the proportion of variability that each of 12 taxonomic groups (at the Order level or above) explained in the richness or composition of other taxa. We then applied optimization to matrices of pairwise congruency to identify the best set of complementary surrogate groups. We found that no single taxon was an optimal surrogate for both the richness and composition of unmeasured taxa if we used simple methods to aggregate congruence data between studies. In contrast, statistical methods that accounted for well-known drivers of cross-taxon congruence (spatial extent, grain size, and latitude) lead to the prioritization of similar surrogates for both species richness and composition. Advanced statistical methods were also more effective at describing known ecological relationships between taxa than simple methods, and show that congruence is typically highest between taxonomically and functionally dissimilar taxa. Birds and vascular plants were most frequently selected by our algorithm as surrogates for other taxonomic groups, but the extent to which any one taxon was the ‘optimal’ choice of surrogate for other biodiversity was highly context-dependent. In the absence of other information – such as in data-poor areas of the globe, and under limited budgets for monitoring or assessment – ecologists can use our results to assess which taxa are most likely to reflect the distribution of the richness or composition of ‘total’ biodiversity. © 2016 The Authors
Optimality conditions via weak subdifferentials in reflexive Banach spaces
- Hassani, Sara, Mammadov, Musa, Jamshidi, Mina
- Authors: Hassani, Sara , Mammadov, Musa , Jamshidi, Mina
- Date: 2017
- Type: Text , Journal article
- Relation: Turkish Journal of Mathematics Vol. 41, no. 1 (2017), p. 1-8
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- Description: In this paper the relation between the weak subdifferentials and the directional derivatives, as well as optimality conditions for nonconvex optimization problems in reflexive Banach spaces, are investigated. It partly generalizes several related results obtained for finite dimensional spaces. © Tübitak.
- Authors: Hassani, Sara , Mammadov, Musa , Jamshidi, Mina
- Date: 2017
- Type: Text , Journal article
- Relation: Turkish Journal of Mathematics Vol. 41, no. 1 (2017), p. 1-8
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- Reviewed:
- Description: In this paper the relation between the weak subdifferentials and the directional derivatives, as well as optimality conditions for nonconvex optimization problems in reflexive Banach spaces, are investigated. It partly generalizes several related results obtained for finite dimensional spaces. © Tübitak.
Optimising the management of invasive aquatic plants targeted for extirpation from catchments and waterways : Utilising alligator weed (Alternanthera philoxeroides (Mart.) Griseb.) as a target species
- Authors: Clements, Daniel
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Aquatic plants are integral components of freshwater ecosystems and provide essential ecosystem services. However, when invasive species establish in new aquatic environments, there are few natural checks and balances to inhibit their growth and spread. Overabundant aquatic vegetation can harm aquatic systems if left unchecked and negatively impact on agricultural productivity, social amenity and biodiversity values. Prevention and early intervention are recognised as the most cost effective means to manage invasive species that pose a biosecurity risk. This thesis contributes to the development of effective management strategies for one of the world’s most invasive aquatic plant species, known as alligator weed (Alternanthera philoxeroides (Mart.) Griseb.). It focusses on developing management strategies in an early stage of invasion, in order to achieve extirpation of this species from catchments and waterways. Developing effective detection and surveillance strategies are required for invasive aquatic plants, as a key impediment to achieving extirpation is the ability to detect infestations, so that control strategies can be enacted. This thesis investigates the effectiveness of aerial surveillance for detection of alligator weed at different spatial scales, using high altitude aerial imagery (orthophotos) and unmanned aerial vehicle (UAV) technology. An examination of the growth rate of alligator weed in Victoria, Australia, over a five year period, demonstrates the effective use of orthophotos to detect and monitor large infestations of aquatic alligator weed. The efficacy of unmanned aerial vehicle technology, including the use of automated algorithms, to detect patches of alligator weed growing in waterways is evaluated against current detection techniques. Effective management of invasive aquatic plants targeted for extirpation requires the coupling of effective detection and control efforts to prevent reproduction. To date, development of control strategies for aquatic alligator weed has been limited to evaluating the efficacy of short-term control at a local scale without regard to the effects of management strategies on dispersal of propagules throughout catchments. This thesis determines that viable alligator weed stem fragments are produced following herbicide application, which comprises extirpation efforts. This thesis has gone further than current practice in that it has evaluated the efficacy of current and novel control techniques, in both laboratory and field trials and has developed methods to manage viable fragment production post-herbicide application, to limit dispersal throughout catchments. In this respect, the application of the herbicides glyphosate, metsulfuron-methyl and imazapyr, and their effectiveness when incorporating surfactant systems and plant growth regulators, have been evaluated in field and laboratory studies to optimise control techniques for aquatic alligator weed. Results have shown that our approaches, when used in an early stage of invasion, are capable of eliminating patches of alligator weed in two to three years. Integral to the research is an experiment to determine the effect of herbicide treatments on the production of alligator weed stem fragments and their subsequent viability. Further investigation to determine the usefulness of commercially available plant growth regulators (PGRs) to reduce the number of viable propagules produced by alligator weed post-herbicide application was found to be ineffective. This thesis also evaluates the impact of herbicides and surfactant systems, on all key alligator weed response metrics in aquatic environments including; above ground biomass, below ground biomass and viable stem fragmentation. No previous studies have looked simultaneously at these three important measures for determining the efficacy of a particular control regime, and we have determined that this is essential for effective management of aquatic alligator weed in an early stage of invasion. The thesis has underscored the notion that development of more effective management strategies, based upon experimental trials, will result in an increased likelihood of eradicating invasive aquatic plants that pose a biosecurity risk, and thus move toward the mitigation of the threat that high-risk species pose to aquatic ecosystems. PLEASE NOTE: Portions of the full text have been removed due to copyright restrictions.
- Description: Doctor of Philosophy
- Authors: Clements, Daniel
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: Aquatic plants are integral components of freshwater ecosystems and provide essential ecosystem services. However, when invasive species establish in new aquatic environments, there are few natural checks and balances to inhibit their growth and spread. Overabundant aquatic vegetation can harm aquatic systems if left unchecked and negatively impact on agricultural productivity, social amenity and biodiversity values. Prevention and early intervention are recognised as the most cost effective means to manage invasive species that pose a biosecurity risk. This thesis contributes to the development of effective management strategies for one of the world’s most invasive aquatic plant species, known as alligator weed (Alternanthera philoxeroides (Mart.) Griseb.). It focusses on developing management strategies in an early stage of invasion, in order to achieve extirpation of this species from catchments and waterways. Developing effective detection and surveillance strategies are required for invasive aquatic plants, as a key impediment to achieving extirpation is the ability to detect infestations, so that control strategies can be enacted. This thesis investigates the effectiveness of aerial surveillance for detection of alligator weed at different spatial scales, using high altitude aerial imagery (orthophotos) and unmanned aerial vehicle (UAV) technology. An examination of the growth rate of alligator weed in Victoria, Australia, over a five year period, demonstrates the effective use of orthophotos to detect and monitor large infestations of aquatic alligator weed. The efficacy of unmanned aerial vehicle technology, including the use of automated algorithms, to detect patches of alligator weed growing in waterways is evaluated against current detection techniques. Effective management of invasive aquatic plants targeted for extirpation requires the coupling of effective detection and control efforts to prevent reproduction. To date, development of control strategies for aquatic alligator weed has been limited to evaluating the efficacy of short-term control at a local scale without regard to the effects of management strategies on dispersal of propagules throughout catchments. This thesis determines that viable alligator weed stem fragments are produced following herbicide application, which comprises extirpation efforts. This thesis has gone further than current practice in that it has evaluated the efficacy of current and novel control techniques, in both laboratory and field trials and has developed methods to manage viable fragment production post-herbicide application, to limit dispersal throughout catchments. In this respect, the application of the herbicides glyphosate, metsulfuron-methyl and imazapyr, and their effectiveness when incorporating surfactant systems and plant growth regulators, have been evaluated in field and laboratory studies to optimise control techniques for aquatic alligator weed. Results have shown that our approaches, when used in an early stage of invasion, are capable of eliminating patches of alligator weed in two to three years. Integral to the research is an experiment to determine the effect of herbicide treatments on the production of alligator weed stem fragments and their subsequent viability. Further investigation to determine the usefulness of commercially available plant growth regulators (PGRs) to reduce the number of viable propagules produced by alligator weed post-herbicide application was found to be ineffective. This thesis also evaluates the impact of herbicides and surfactant systems, on all key alligator weed response metrics in aquatic environments including; above ground biomass, below ground biomass and viable stem fragmentation. No previous studies have looked simultaneously at these three important measures for determining the efficacy of a particular control regime, and we have determined that this is essential for effective management of aquatic alligator weed in an early stage of invasion. The thesis has underscored the notion that development of more effective management strategies, based upon experimental trials, will result in an increased likelihood of eradicating invasive aquatic plants that pose a biosecurity risk, and thus move toward the mitigation of the threat that high-risk species pose to aquatic ecosystems. PLEASE NOTE: Portions of the full text have been removed due to copyright restrictions.
- Description: Doctor of Philosophy
Optimization of cement-based grouts using chemical additives
- Azadi, Mohammadreza, Taghichian, Ali, Taheri, Ali
- Authors: Azadi, Mohammadreza , Taghichian, Ali , Taheri, Ali
- Date: 2017
- Type: Text , Journal article
- Relation: Journal of Rock Mechanics and Geotechnical Engineering Vol. 9, no. 4 (2017), p. 623-637
- Full Text:
- Reviewed:
- Description: Grout injection is used for sealing or strengthening the ground in order to prevent water entrance or any failure after excavation. There are many methods of grouting. Permeation grouting is one of the most common types in which the grout material is injected to the pore spaces of the ground. In grouting operations, the grout quality is important to achieve the best results. There are four main characteristics for a grout mixture including bleeding, setting time, strength, and viscosity. In this paper, we try to build some efficient grouting mixtures with different water to cement ratios considering these characteristics. The ingredients of grout mixtures built in this study are cement, water, bentonite, and some chemical additives such as sodium silicate, sodium carbonate, and triethanolamine (TEA). The grout mixtures are prepared for both of the sealing and strengthening purposes for a structural project. Effect of each above-mentioned ingredient is profoundly investigated. Since each ingredient may have positive or negative aspect, an optimization of appropriate amount of each ingredient is determined. The optimization is based on 200 grout mixture samples with different percentages of ingredients. Finally, some of these grout mixtures are chosen for the introduced project. It should be mentioned that grouting operations depend on various factors such as pressure of injection, ground structure and grain size of soils. However, quality of a grout can be helpful to make an injection easier and reasonable. For example, during the injection, a wrong estimated setting time can destroy the injected grout by washing the grout or setting early which prevents grouting. This paper tries to show some tests in easy way to achieve a desirable sample of grout. © 2017 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
- Authors: Azadi, Mohammadreza , Taghichian, Ali , Taheri, Ali
- Date: 2017
- Type: Text , Journal article
- Relation: Journal of Rock Mechanics and Geotechnical Engineering Vol. 9, no. 4 (2017), p. 623-637
- Full Text:
- Reviewed:
- Description: Grout injection is used for sealing or strengthening the ground in order to prevent water entrance or any failure after excavation. There are many methods of grouting. Permeation grouting is one of the most common types in which the grout material is injected to the pore spaces of the ground. In grouting operations, the grout quality is important to achieve the best results. There are four main characteristics for a grout mixture including bleeding, setting time, strength, and viscosity. In this paper, we try to build some efficient grouting mixtures with different water to cement ratios considering these characteristics. The ingredients of grout mixtures built in this study are cement, water, bentonite, and some chemical additives such as sodium silicate, sodium carbonate, and triethanolamine (TEA). The grout mixtures are prepared for both of the sealing and strengthening purposes for a structural project. Effect of each above-mentioned ingredient is profoundly investigated. Since each ingredient may have positive or negative aspect, an optimization of appropriate amount of each ingredient is determined. The optimization is based on 200 grout mixture samples with different percentages of ingredients. Finally, some of these grout mixtures are chosen for the introduced project. It should be mentioned that grouting operations depend on various factors such as pressure of injection, ground structure and grain size of soils. However, quality of a grout can be helpful to make an injection easier and reasonable. For example, during the injection, a wrong estimated setting time can destroy the injected grout by washing the grout or setting early which prevents grouting. This paper tries to show some tests in easy way to achieve a desirable sample of grout. © 2017 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
Parenteral administration of factor Xa/IIa inhibitors limits experimental aortic aneurysm and atherosclerosis
- Moran, Corey, Seto, Sai-Wang, Krishna, Smriti, Sharma, Surabhi, Jose, Roby, Biros, Erik, Wang, Yutang, Morton, Susan, Golledge, Jonathan
- Authors: Moran, Corey , Seto, Sai-Wang , Krishna, Smriti , Sharma, Surabhi , Jose, Roby , Biros, Erik , Wang, Yutang , Morton, Susan , Golledge, Jonathan
- Date: 2017
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 7, no. (2017), p. 1-12
- Full Text:
- Reviewed:
- Description: Intraluminal thrombus is a consistent feature of human abdominal aortic aneurysm (AAA). Coagulation factor Xa (FXa) catalyses FII to thrombin (FIIa). We examined the effect of FXa/FIIa inhibition on experimental aortic aneurysm in apolipoprotein E-deficient (ApoE '/') mice infused with angiotensin II (AngII). The concentration of FXa within the supra-renal aorta (SRA) correlated positively with SRA diameter. Parenteral administration of enoxaparin (FXa/IIa inhibitor) and fondaparinux (FXa inhibitor) over 14 days reduced to severity of aortic aneurysm and atherosclerosis in AngII-infused ApoE '/' mice. Enteral administration of the FIIa inhibitor dabigatran had no significant effect. Aortic protease-activated receptor (PAR)-2 expression increased in response to AngII infusion. Fondaparinux reduced SRA levels of FXa, FIIa, PAR-2, matrix metalloproteinase (MMP)2, Smad2/3 phosphorylation, and MOMA-2 positive cells in the mouse model. FXa stimulated Smad2/3 phosphorylation and MMP2 expression in aortic vascular smooth muscle cells (VSMC) in vitro. Expression of MMP2 in FXa-stimulated VSMC was downregulated in the presence of a PAR-2 but not a PAR-1 inhibitor. These findings suggest that FXa/FIIa inhibition limits aortic aneurysm and atherosclerosis severity due to down-regulation of vascular PAR-2-mediated Smad2/3 signalling and MMP2 expression. Inhibition of FXa/FIIa may be a potential therapy for limiting aortic aneurysm. © The Author(s) 2017.
- Authors: Moran, Corey , Seto, Sai-Wang , Krishna, Smriti , Sharma, Surabhi , Jose, Roby , Biros, Erik , Wang, Yutang , Morton, Susan , Golledge, Jonathan
- Date: 2017
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 7, no. (2017), p. 1-12
- Full Text:
- Reviewed:
- Description: Intraluminal thrombus is a consistent feature of human abdominal aortic aneurysm (AAA). Coagulation factor Xa (FXa) catalyses FII to thrombin (FIIa). We examined the effect of FXa/FIIa inhibition on experimental aortic aneurysm in apolipoprotein E-deficient (ApoE '/') mice infused with angiotensin II (AngII). The concentration of FXa within the supra-renal aorta (SRA) correlated positively with SRA diameter. Parenteral administration of enoxaparin (FXa/IIa inhibitor) and fondaparinux (FXa inhibitor) over 14 days reduced to severity of aortic aneurysm and atherosclerosis in AngII-infused ApoE '/' mice. Enteral administration of the FIIa inhibitor dabigatran had no significant effect. Aortic protease-activated receptor (PAR)-2 expression increased in response to AngII infusion. Fondaparinux reduced SRA levels of FXa, FIIa, PAR-2, matrix metalloproteinase (MMP)2, Smad2/3 phosphorylation, and MOMA-2 positive cells in the mouse model. FXa stimulated Smad2/3 phosphorylation and MMP2 expression in aortic vascular smooth muscle cells (VSMC) in vitro. Expression of MMP2 in FXa-stimulated VSMC was downregulated in the presence of a PAR-2 but not a PAR-1 inhibitor. These findings suggest that FXa/FIIa inhibition limits aortic aneurysm and atherosclerosis severity due to down-regulation of vascular PAR-2-mediated Smad2/3 signalling and MMP2 expression. Inhibition of FXa/FIIa may be a potential therapy for limiting aortic aneurysm. © The Author(s) 2017.
Participation trends in holistic movement practices : A 10-year comparison of yoga/Pilates and t'ai chi/qigong use among a national sample of 195,926 Australians
- Vergeer, Ineke, Bennie, Jason, Charity, Melanie, Harvey, Jack, van Uffelen, Jannique, Biddle, Stuart, Eime, Rochelle
- Authors: Vergeer, Ineke , Bennie, Jason , Charity, Melanie , Harvey, Jack , van Uffelen, Jannique , Biddle, Stuart , Eime, Rochelle
- Date: 2017
- Type: Text , Journal article
- Relation: BMC Complementary and Alternative Medicine Vol. 17, no. 1 (2017), p. 1-13
- Full Text:
- Reviewed:
- Description: Background: In recent decades, the evidence supporting the physical and mental health benefits of holistic movement practices such as yoga and t'ai chi have become increasingly established. Consequently, investigating the participation prevalence and patterns of these practices is a relevant pursuit in the public health field. Few studies have provided population-level assessment of participation rates, however, and even fewer have focused on patterns over time. The purpose of this study was to examine participation prevalence and trends in yoga/Pilates and t'ai chi/qigong over a ten-year period in a nationally representative sample of Australians aged 15 years and over, with particular attention to sex and age. A secondary purpose was to juxtapose these findings with participation trends in traditional fitness activities over the same period. Methods: Data comprised modes and types of physical activity, age, and sex variables collected through the Exercise, Recreation and Sport Survey (ERASS), a series of independent cross-sectional Australia-wide surveys conducted yearly between 2001 and 2010. For each year, weighted population estimates were calculated for those participating in yoga/Pilates, t'ai chi/qigong, and fitness activities (e.g. aerobics, calisthenics). Linear regression and multiple logistic regression analyses were used to examine trends in prevalence rates over time and differences among sex and age (15-34; 35-54; 55+ years) groups, respectively. Results: Average prevalence rates between 2001 and 2010 were 3.0% (95% CI 2.9-3.1) for yoga/Pilates, 0.6% (95% CI 0.5-0.6) for t'ai chi/qigong, and 19.2% (95% CI 18.9-19.4) for fitness activities. Across the decade, overall participation rates remained relatively stable for yoga/Pilates and t'ai chi/qigong, while increasing linearly for fitness activities. For both genders and in all three age groups, participation in fitness activities increased, whereas only in the 55+ age group was there a significant increase in yoga/Pilates participation; participation in t'ai chi/qigong declined significantly in the two younger age groups. Conclusions: Participation rates in yoga/Pilates and t'ai chi/qigong in Australia were low and relatively stable. As fitness activities increased in popularity across the decade, holistic movement practices did not. These findings point to the need to investigate activity-specific barriers and facilitators to participation, including intrapersonal, interpersonal, organisational, and environmental factors. © 2017 The Author(s).
- Authors: Vergeer, Ineke , Bennie, Jason , Charity, Melanie , Harvey, Jack , van Uffelen, Jannique , Biddle, Stuart , Eime, Rochelle
- Date: 2017
- Type: Text , Journal article
- Relation: BMC Complementary and Alternative Medicine Vol. 17, no. 1 (2017), p. 1-13
- Full Text:
- Reviewed:
- Description: Background: In recent decades, the evidence supporting the physical and mental health benefits of holistic movement practices such as yoga and t'ai chi have become increasingly established. Consequently, investigating the participation prevalence and patterns of these practices is a relevant pursuit in the public health field. Few studies have provided population-level assessment of participation rates, however, and even fewer have focused on patterns over time. The purpose of this study was to examine participation prevalence and trends in yoga/Pilates and t'ai chi/qigong over a ten-year period in a nationally representative sample of Australians aged 15 years and over, with particular attention to sex and age. A secondary purpose was to juxtapose these findings with participation trends in traditional fitness activities over the same period. Methods: Data comprised modes and types of physical activity, age, and sex variables collected through the Exercise, Recreation and Sport Survey (ERASS), a series of independent cross-sectional Australia-wide surveys conducted yearly between 2001 and 2010. For each year, weighted population estimates were calculated for those participating in yoga/Pilates, t'ai chi/qigong, and fitness activities (e.g. aerobics, calisthenics). Linear regression and multiple logistic regression analyses were used to examine trends in prevalence rates over time and differences among sex and age (15-34; 35-54; 55+ years) groups, respectively. Results: Average prevalence rates between 2001 and 2010 were 3.0% (95% CI 2.9-3.1) for yoga/Pilates, 0.6% (95% CI 0.5-0.6) for t'ai chi/qigong, and 19.2% (95% CI 18.9-19.4) for fitness activities. Across the decade, overall participation rates remained relatively stable for yoga/Pilates and t'ai chi/qigong, while increasing linearly for fitness activities. For both genders and in all three age groups, participation in fitness activities increased, whereas only in the 55+ age group was there a significant increase in yoga/Pilates participation; participation in t'ai chi/qigong declined significantly in the two younger age groups. Conclusions: Participation rates in yoga/Pilates and t'ai chi/qigong in Australia were low and relatively stable. As fitness activities increased in popularity across the decade, holistic movement practices did not. These findings point to the need to investigate activity-specific barriers and facilitators to participation, including intrapersonal, interpersonal, organisational, and environmental factors. © 2017 The Author(s).
Past and future ecosystem change in the coastal zone
- Authors: Gell, Peter
- Date: 2017
- Type: Text , Conference proceedings , Conference paper
- Relation: 2nd International Conference on Tropical and Coastal Region Eco Development 2016, ICTCRED 2016; Bali, Indonesia; 25th-27th October 2016; published in IOP Conference Series: Earth and Environmental Science Vol. 55, p. 1-8
- Full Text:
- Reviewed:
- Description: The coastal zone is in a constant state of flux. Long term records of change attest to high amplitude sea level changes. Relative stability though the Late Holocene has allowed for the evolution of barrier dune systems, estuaries and coastal lakes with associated plant and faunal associations. This evolution has been interspersed with changes in the balance between climate driven changes in outflow from catchments. These interactions have been considerably disturbed through the impacts of industrialised people who have diverted and consumed water and invested in infrastructure that has impacted on river flows and the tidal prism in estuaries. This has impacted their provisioning services to humans. It has also impacted their regulating services in that development along the coastline has impacted on the resilience of the littoral zone to absorb natural climate extremes. Looking from the past we can see the pathway to the future and more easily recognise the steps needed to avoid further coastal degradation. This will increasingly need to accommodate the impacts of future climate trends, increased climate extremes and rising seas. Coastal societies would do well to identify their long term pathway to adaptation to the challenges that lie ahead and plan to invest accordingly. © Published under licence by IOP Publishing Ltd.
- Description: IOP Conference Series: Earth and Environmental Science
- Authors: Gell, Peter
- Date: 2017
- Type: Text , Conference proceedings , Conference paper
- Relation: 2nd International Conference on Tropical and Coastal Region Eco Development 2016, ICTCRED 2016; Bali, Indonesia; 25th-27th October 2016; published in IOP Conference Series: Earth and Environmental Science Vol. 55, p. 1-8
- Full Text:
- Reviewed:
- Description: The coastal zone is in a constant state of flux. Long term records of change attest to high amplitude sea level changes. Relative stability though the Late Holocene has allowed for the evolution of barrier dune systems, estuaries and coastal lakes with associated plant and faunal associations. This evolution has been interspersed with changes in the balance between climate driven changes in outflow from catchments. These interactions have been considerably disturbed through the impacts of industrialised people who have diverted and consumed water and invested in infrastructure that has impacted on river flows and the tidal prism in estuaries. This has impacted their provisioning services to humans. It has also impacted their regulating services in that development along the coastline has impacted on the resilience of the littoral zone to absorb natural climate extremes. Looking from the past we can see the pathway to the future and more easily recognise the steps needed to avoid further coastal degradation. This will increasingly need to accommodate the impacts of future climate trends, increased climate extremes and rising seas. Coastal societies would do well to identify their long term pathway to adaptation to the challenges that lie ahead and plan to invest accordingly. © Published under licence by IOP Publishing Ltd.
- Description: IOP Conference Series: Earth and Environmental Science
Perceived injury risk among junior cricketers : A cross sectional survey
- Gamage, Prasanna, Fortington, Lauren, Finch, Caroline
- Authors: Gamage, Prasanna , Fortington, Lauren , Finch, Caroline
- Date: 2017
- Type: Text , Journal article
- Relation: International Journal of Environmental Research and Public Health Vol. 14, no. 8 (2017), p. 1-11
- Full Text:
- Reviewed:
- Description: Understanding how junior athletes perceive injury risks when participating in sport and the environment they play in is an important component of injury prevention. This study investigates how Sri Lankan junior cricketers (n = 365, aged 11–14 years, boys) perceive injury risks associated with playing cricket. The study used a Sri Lankan modification of an Australian junior cricket injury risk perception survey that considered playing cricket versus other sports, different cricket playing positions and roles, and different ground conditions. The risk of playing cricket was considered to be greater than that for cycling, but lower than that for rugby and soccer. Fast-bowlers, batters facing fast-bowlers, fielding close in the field, and wicket-keeping without a helmet were perceived to pose greater risks of injury than other scenarios. Playing on hard, bumpy and/or wet ground conditions were perceived to have a high risk opposed to playing on a grass field. Fielding in the outfield and wicket-keeping to fast-bowlers whilst wearing a helmet were perceived as low risk actions. The risk perceptions of junior cricketers identified in this study, do not necessarily reflect the true injury risk in some instances. This information will inform the development of injury prevention education interventions to address these risk perceptions in junior cricketers. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.
- Authors: Gamage, Prasanna , Fortington, Lauren , Finch, Caroline
- Date: 2017
- Type: Text , Journal article
- Relation: International Journal of Environmental Research and Public Health Vol. 14, no. 8 (2017), p. 1-11
- Full Text:
- Reviewed:
- Description: Understanding how junior athletes perceive injury risks when participating in sport and the environment they play in is an important component of injury prevention. This study investigates how Sri Lankan junior cricketers (n = 365, aged 11–14 years, boys) perceive injury risks associated with playing cricket. The study used a Sri Lankan modification of an Australian junior cricket injury risk perception survey that considered playing cricket versus other sports, different cricket playing positions and roles, and different ground conditions. The risk of playing cricket was considered to be greater than that for cycling, but lower than that for rugby and soccer. Fast-bowlers, batters facing fast-bowlers, fielding close in the field, and wicket-keeping without a helmet were perceived to pose greater risks of injury than other scenarios. Playing on hard, bumpy and/or wet ground conditions were perceived to have a high risk opposed to playing on a grass field. Fielding in the outfield and wicket-keeping to fast-bowlers whilst wearing a helmet were perceived as low risk actions. The risk perceptions of junior cricketers identified in this study, do not necessarily reflect the true injury risk in some instances. This information will inform the development of injury prevention education interventions to address these risk perceptions in junior cricketers. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.
Perceived organisational support and expatriation in Ghana
- Authors: Sokro, Evans
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis explores the relationship between perceived organisational support and expatriation outcomes in host subsidiaries of multinational companies. While multinationals depend on expatriates to manage their foreign subsidiaries, successful expatriation is influenced by expatriates’ cross-cultural adjustment to the host country’s environments. Although Ghana has witnessed a substantial growth in the number of foreign subsidiaries operating in various sectors of the country’s economy, support structures have not been well researched in terms of how host organisations manage expatriation, considered from an African perspective. Adopting a positivist research approach, this study surveyed 229 expatriates working in foreign subsidiaries of multinational companies based in Ghana. Structural equation modelling was employed to test the model and hypothesised relationships. The test of the hypothesised model reveals that support from the organisation and host employees has significant positive effects on expatriation. Specifically, the study shows that perceived organisational support positively relates to expatriate assignment completion and career development. Host-country nationals’ support has a significant effect on expatriate adjustment to the work environment but no effect on Ghanaian cultural adjustment. The empirical results indicate that headquarters-subsidiary coordination has significant positive effects on expatriate adjustment to the host country’s environment and on how the subsidiary is shaped through knowledge transfer. In contrast, Ghanaian cultural adjustment was found to have a negative impact on assignment completion and shaping of the subsidiary. Furthermore, while assignment completion is positively related to career and professional skills development, shaping the subsidiary has a direct effect on overall success. Career development and overall success are significantly associated with expatriate satisfaction. This thesis concludes by discussing the implications of the findings of the study for both theory and practice. The limitations of the study are acknowledged and explained. Several recommendations for future research are detailed to ensure successful expatriation in sub-Saharan Africa in general.
- Description: Doctor of Philosophy
- Authors: Sokro, Evans
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis explores the relationship between perceived organisational support and expatriation outcomes in host subsidiaries of multinational companies. While multinationals depend on expatriates to manage their foreign subsidiaries, successful expatriation is influenced by expatriates’ cross-cultural adjustment to the host country’s environments. Although Ghana has witnessed a substantial growth in the number of foreign subsidiaries operating in various sectors of the country’s economy, support structures have not been well researched in terms of how host organisations manage expatriation, considered from an African perspective. Adopting a positivist research approach, this study surveyed 229 expatriates working in foreign subsidiaries of multinational companies based in Ghana. Structural equation modelling was employed to test the model and hypothesised relationships. The test of the hypothesised model reveals that support from the organisation and host employees has significant positive effects on expatriation. Specifically, the study shows that perceived organisational support positively relates to expatriate assignment completion and career development. Host-country nationals’ support has a significant effect on expatriate adjustment to the work environment but no effect on Ghanaian cultural adjustment. The empirical results indicate that headquarters-subsidiary coordination has significant positive effects on expatriate adjustment to the host country’s environment and on how the subsidiary is shaped through knowledge transfer. In contrast, Ghanaian cultural adjustment was found to have a negative impact on assignment completion and shaping of the subsidiary. Furthermore, while assignment completion is positively related to career and professional skills development, shaping the subsidiary has a direct effect on overall success. Career development and overall success are significantly associated with expatriate satisfaction. This thesis concludes by discussing the implications of the findings of the study for both theory and practice. The limitations of the study are acknowledged and explained. Several recommendations for future research are detailed to ensure successful expatriation in sub-Saharan Africa in general.
- Description: Doctor of Philosophy
Perspectives of aboriginal issues among non-aboriginal residents of rural Victorian communities
- Bourke, Lisa, Malatzky, Christina, Terry, Daniel, Nixon, Raelene, Ferguson, Karyn, Ferguson, Peter
- Authors: Bourke, Lisa , Malatzky, Christina , Terry, Daniel , Nixon, Raelene , Ferguson, Karyn , Ferguson, Peter
- Date: 2017
- Type: Text , Journal article
- Relation: Australian Journal of Social Issues Vol. 52, no. 3 (2017), p. 278-293
- Full Text:
- Reviewed:
- Description: Racism, in various forms, remains a dominant feature in Australian society. Aboriginal Australians are commonly targets of racial discrimination. However, understanding racism is difficult given that racial attitudes vary towards particular groups of people, across place and time and are difficult to measure. This paper presents responses of residents across four rural shires in Victoria to questions about attitudes towards Aboriginal people/issues. Responses indicated that attitudes towards Aboriginal people were diverse and that individuals varied in their attitudes on specific items. There were subtle differences between the four sites and association between demographic characteristics and some items in particular sites. This suggests that respondents are inconsistent in their attitudes relating to Aboriginal people/issues and that there are place-based influences on these attitudes. We conclude that the many varied understandings of racism and Aboriginal Australians allow the discourses of exclusion, disempowerment and othering to be maintained. © 2017 Australian Social Policy Association.
- Authors: Bourke, Lisa , Malatzky, Christina , Terry, Daniel , Nixon, Raelene , Ferguson, Karyn , Ferguson, Peter
- Date: 2017
- Type: Text , Journal article
- Relation: Australian Journal of Social Issues Vol. 52, no. 3 (2017), p. 278-293
- Full Text:
- Reviewed:
- Description: Racism, in various forms, remains a dominant feature in Australian society. Aboriginal Australians are commonly targets of racial discrimination. However, understanding racism is difficult given that racial attitudes vary towards particular groups of people, across place and time and are difficult to measure. This paper presents responses of residents across four rural shires in Victoria to questions about attitudes towards Aboriginal people/issues. Responses indicated that attitudes towards Aboriginal people were diverse and that individuals varied in their attitudes on specific items. There were subtle differences between the four sites and association between demographic characteristics and some items in particular sites. This suggests that respondents are inconsistent in their attitudes relating to Aboriginal people/issues and that there are place-based influences on these attitudes. We conclude that the many varied understandings of racism and Aboriginal Australians allow the discourses of exclusion, disempowerment and othering to be maintained. © 2017 Australian Social Policy Association.
Pixel N-grams for Mammographic Image Classification
- Authors: Kulkarni, Pradnya
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: X-ray screening for breast cancer is an important public health initiative in the management of a leading cause of death for women. However, screening is expensive if mammograms are required to be manually assessed by radiologists. Moreover, manual screening is subject to perception and interpretation errors. Computer aided detection/diagnosis (CAD) systems can help radiologists as computer algorithms are good at performing image analysis consistently and repetitively. However, image features that enhance CAD classification accuracies are necessary for CAD systems to be deployed. Many CAD systems have been developed but the specificity and sensitivity is not high; in part because of challenges inherent in identifying effective features to be initially extracted from raw images. Existing feature extraction techniques can be grouped under three main approaches; statistical, spectral and structural. Statistical and spectral techniques provide global image features but often fail to distinguish between local pattern variations within an image. On the other hand, structural approach have given rise to the Bag-of-Visual-Words (BoVW) model, which captures local variations in an image, but typically do not consider spatial relationships between the visual “words”. Moreover, statistical features and features based on BoVW models are computationally very expensive. Similarly, structural feature computation methods other than BoVW are also computationally expensive and strongly dependent upon algorithms that can segment an image to localize a region of interest likely to contain the tumour. Thus, classification algorithms using structural features require high resource computers. In order for a radiologist to classify the lesions on low resource computers such as Ipads, Tablets, and Mobile phones, in a remote location, it is necessary to develop computationally inexpensive classification algorithms. Therefore, the overarching aim of this research is to discover a feature extraction/image representation model which can be used to classify mammographic lesions with high accuracy, sensitivity and specificity along with low computational cost. For this purpose a novel feature extraction technique called ‘Pixel N-grams’ is proposed. The Pixel N-grams approach is inspired from the character N-gram concept in text categorization. Here, N number of consecutive pixel intensities are considered in a particular direction. The image is then represented with the help of histogram of occurrences of the Pixel N-grams in an image. Shape and texture of mammographic lesions play an important role in determining the malignancy of the lesion. It was hypothesized that the Pixel N-grams would be able to distinguish between various textures and shapes. Experiments carried out on benchmark texture databases and binary basic shapes database have demonstrated that the hypothesis was correct. Moreover, the Pixel N-grams were able to distinguish between various shapes irrespective of size and location of shape in an image. The efficacy of the Pixel N-gram technique was tested on mammographic database of primary digital mammograms sourced from a radiological facility in Australia (LakeImaging Pty Ltd) and secondary digital mammograms (benchmark miniMIAS database). A senior radiologist from LakeImaging provided real time de-identified high resolution mammogram images with annotated regions of interests (which were used as groundtruth), and valuable radiological diagnostic knowledge. Two types of classifications were observed on these two datasets. Normal/abnormal classification useful for automated screening and circumscribed/speculation/normal classification useful for automated diagnosis of breast cancer. The classification results on both the mammography datasets using Pixel N-grams were promising. Classification performance (Fscore, sensitivity and specificity) using Pixel N-gram technique was observed to be significantly better than the existing techniques such as intensity histogram, co-occurrence matrix based features and comparable with the BoVW features. Further, Pixel N-gram features are found to be computationally less complex than the co-occurrence matrix based features as well as BoVW features paving the way for mammogram classification on low resource computers. Although, the Pixel N-gram technique was designed for mammographic classification, it could be applied to other image classification applications such as diabetic retinopathy, histopathological image classification, lung tumour detection using CT images, brain tumour detection using MRI images, wound image classification and tooth decay classification using dentistry x-ray images. Further, texture and shape classification is also useful for classification of real world images outside the medical domain. Therefore, the pixel N-gram technique could be extended for applications such as classification of satellite imagery and other object detection tasks.
- Description: Doctor of Philosophy
- Authors: Kulkarni, Pradnya
- Date: 2017
- Type: Text , Thesis , PhD
- Full Text:
- Description: X-ray screening for breast cancer is an important public health initiative in the management of a leading cause of death for women. However, screening is expensive if mammograms are required to be manually assessed by radiologists. Moreover, manual screening is subject to perception and interpretation errors. Computer aided detection/diagnosis (CAD) systems can help radiologists as computer algorithms are good at performing image analysis consistently and repetitively. However, image features that enhance CAD classification accuracies are necessary for CAD systems to be deployed. Many CAD systems have been developed but the specificity and sensitivity is not high; in part because of challenges inherent in identifying effective features to be initially extracted from raw images. Existing feature extraction techniques can be grouped under three main approaches; statistical, spectral and structural. Statistical and spectral techniques provide global image features but often fail to distinguish between local pattern variations within an image. On the other hand, structural approach have given rise to the Bag-of-Visual-Words (BoVW) model, which captures local variations in an image, but typically do not consider spatial relationships between the visual “words”. Moreover, statistical features and features based on BoVW models are computationally very expensive. Similarly, structural feature computation methods other than BoVW are also computationally expensive and strongly dependent upon algorithms that can segment an image to localize a region of interest likely to contain the tumour. Thus, classification algorithms using structural features require high resource computers. In order for a radiologist to classify the lesions on low resource computers such as Ipads, Tablets, and Mobile phones, in a remote location, it is necessary to develop computationally inexpensive classification algorithms. Therefore, the overarching aim of this research is to discover a feature extraction/image representation model which can be used to classify mammographic lesions with high accuracy, sensitivity and specificity along with low computational cost. For this purpose a novel feature extraction technique called ‘Pixel N-grams’ is proposed. The Pixel N-grams approach is inspired from the character N-gram concept in text categorization. Here, N number of consecutive pixel intensities are considered in a particular direction. The image is then represented with the help of histogram of occurrences of the Pixel N-grams in an image. Shape and texture of mammographic lesions play an important role in determining the malignancy of the lesion. It was hypothesized that the Pixel N-grams would be able to distinguish between various textures and shapes. Experiments carried out on benchmark texture databases and binary basic shapes database have demonstrated that the hypothesis was correct. Moreover, the Pixel N-grams were able to distinguish between various shapes irrespective of size and location of shape in an image. The efficacy of the Pixel N-gram technique was tested on mammographic database of primary digital mammograms sourced from a radiological facility in Australia (LakeImaging Pty Ltd) and secondary digital mammograms (benchmark miniMIAS database). A senior radiologist from LakeImaging provided real time de-identified high resolution mammogram images with annotated regions of interests (which were used as groundtruth), and valuable radiological diagnostic knowledge. Two types of classifications were observed on these two datasets. Normal/abnormal classification useful for automated screening and circumscribed/speculation/normal classification useful for automated diagnosis of breast cancer. The classification results on both the mammography datasets using Pixel N-grams were promising. Classification performance (Fscore, sensitivity and specificity) using Pixel N-gram technique was observed to be significantly better than the existing techniques such as intensity histogram, co-occurrence matrix based features and comparable with the BoVW features. Further, Pixel N-gram features are found to be computationally less complex than the co-occurrence matrix based features as well as BoVW features paving the way for mammogram classification on low resource computers. Although, the Pixel N-gram technique was designed for mammographic classification, it could be applied to other image classification applications such as diabetic retinopathy, histopathological image classification, lung tumour detection using CT images, brain tumour detection using MRI images, wound image classification and tooth decay classification using dentistry x-ray images. Further, texture and shape classification is also useful for classification of real world images outside the medical domain. Therefore, the pixel N-gram technique could be extended for applications such as classification of satellite imagery and other object detection tasks.
- Description: Doctor of Philosophy
Plastic dilation rate characteristic of concrete confined with steel tube
- Piscesa, Bambang, Attard, Mario, Samani, Ali Khajeh
- Authors: Piscesa, Bambang , Attard, Mario , Samani, Ali Khajeh
- Date: 2017
- Type: Text , Conference paper
- Relation: 14th International Conference on Computational Plasticity - Fundamentals and Applications, COMPLAS 2017; Barcelona, Spain; 5th-7th September 2017 p. 436-446
- Full Text:
- Reviewed:
- Description: The use of external confining devices to confine concrete has become widely used. One of the purposes is to gain additional concrete strength and ductility. Although there are many types of external confining devices, in this paper, the attention is limited to the use of the steel tube as an external confining device. One of the main objectives of this research is to study the plastic dilation rate behavior of concrete-filled-steel-tube (CFST) columns. The experimental data for the plastic dilation rate is extracted, and compared with the authors concrete plasticity model. In the authors’ previous research, the calibration of the plastic dilation rate model was based on confined concrete tested under both active and passive confinement using FRP wraps. Since the behavior of the steel tube and the FRP materials are different, the author’s plastic dilation rate model needs to be re-evaluated for CFST columns. Comparisons of the extracted experimental plastic dilation rates with the model prediction for CFST specimens with normal strength concrete show good agreement and requires no adjustment in the formulation. However, for a specimen with 80 MPa concrete, the proposed formulation shows slightly lower plastic dilation rates. More experimental data for CFST using high strength concretes is required for further investigation. For the sake of completeness, the overall response of two CFST specimens is also evaluated using an in-house three-dimensional non-linear finite element analysis (3D-NLFEA) using the author’s proposed plasticity formulation for confined concrete.
- Authors: Piscesa, Bambang , Attard, Mario , Samani, Ali Khajeh
- Date: 2017
- Type: Text , Conference paper
- Relation: 14th International Conference on Computational Plasticity - Fundamentals and Applications, COMPLAS 2017; Barcelona, Spain; 5th-7th September 2017 p. 436-446
- Full Text:
- Reviewed:
- Description: The use of external confining devices to confine concrete has become widely used. One of the purposes is to gain additional concrete strength and ductility. Although there are many types of external confining devices, in this paper, the attention is limited to the use of the steel tube as an external confining device. One of the main objectives of this research is to study the plastic dilation rate behavior of concrete-filled-steel-tube (CFST) columns. The experimental data for the plastic dilation rate is extracted, and compared with the authors concrete plasticity model. In the authors’ previous research, the calibration of the plastic dilation rate model was based on confined concrete tested under both active and passive confinement using FRP wraps. Since the behavior of the steel tube and the FRP materials are different, the author’s plastic dilation rate model needs to be re-evaluated for CFST columns. Comparisons of the extracted experimental plastic dilation rates with the model prediction for CFST specimens with normal strength concrete show good agreement and requires no adjustment in the formulation. However, for a specimen with 80 MPa concrete, the proposed formulation shows slightly lower plastic dilation rates. More experimental data for CFST using high strength concretes is required for further investigation. For the sake of completeness, the overall response of two CFST specimens is also evaluated using an in-house three-dimensional non-linear finite element analysis (3D-NLFEA) using the author’s proposed plasticity formulation for confined concrete.
Power transaction management amongst coupled microgrids in remote areas
- Batool, Munira, Islam, Syed, Shahnia, Farhad
- Authors: Batool, Munira , Islam, Syed , Shahnia, Farhad
- Date: 2017
- Type: Text , Conference proceedings , Conference paper
- Relation: 7th IEEE Innovative Smart Grid Technologies - Asia, ISGT-Asia 2017;Auckland, New Zealand; 4th-7th December 2017 p. 1-6
- Full Text:
- Reviewed:
- Description: Large remote areas normally have isolated and self-sufficient electricity supply systems, often referred to as microgrids. These systems also rely on a mix of dispatchable and non-dispatcha- ble distributed energy resources to reduce the overall cost of electricity production. Emergencies such as shortfalls, overloading, and faults can cause problems in the operation of these remote area microgrids. This paper presents a power transaction management scheme amongst a few such microgrids when they are coupled provisionally during emergencies. By definition, power transaction is an instance of buying and selling of electricity amongst problem and healthy microgrids. The developed technique aims to define the suitable power generation from all dispatchable sources and regulate the power transaction amongst the coupled microgrids. To this end, an optimization problem is formulated that aims to define the above parameters while minimizing the costs and technical impacts. A mixed- integer linear programming technique is used to solve the formulated problem. The performance of the proposed management strategy is evaluated by numerical analysis in MATLAB.
- Authors: Batool, Munira , Islam, Syed , Shahnia, Farhad
- Date: 2017
- Type: Text , Conference proceedings , Conference paper
- Relation: 7th IEEE Innovative Smart Grid Technologies - Asia, ISGT-Asia 2017;Auckland, New Zealand; 4th-7th December 2017 p. 1-6
- Full Text:
- Reviewed:
- Description: Large remote areas normally have isolated and self-sufficient electricity supply systems, often referred to as microgrids. These systems also rely on a mix of dispatchable and non-dispatcha- ble distributed energy resources to reduce the overall cost of electricity production. Emergencies such as shortfalls, overloading, and faults can cause problems in the operation of these remote area microgrids. This paper presents a power transaction management scheme amongst a few such microgrids when they are coupled provisionally during emergencies. By definition, power transaction is an instance of buying and selling of electricity amongst problem and healthy microgrids. The developed technique aims to define the suitable power generation from all dispatchable sources and regulate the power transaction amongst the coupled microgrids. To this end, an optimization problem is formulated that aims to define the above parameters while minimizing the costs and technical impacts. A mixed- integer linear programming technique is used to solve the formulated problem. The performance of the proposed management strategy is evaluated by numerical analysis in MATLAB.
Presenting a 4-Item spiritual well-being index (4-ISWBI)
- Authors: Fisher, John , Ng, David
- Date: 2017
- Type: Text , Journal article
- Relation: Religions Vol. 8, no. 9 (2017), p. 1-13
- Full Text:
- Reviewed:
- Description: Spiritual well-being is perceived to be reflected in the quality of relationships that people have in four areas, namely with God, others, nature, and self. Many spiritual well-being questionnaires exist, but not many provide an adequate assessment of these four relationships. As part of a survey of parental perceptions of holistic early childhood education in kindergartens in Hong Kong, 1383 parents and 165 teachers, from 22 kindergartens, completed a written survey questionnaire which helped to investigate the potential for a single question with four parts to provide a valid and reliable measure for spiritual well-being. Face, content, and construct validity were confirmed, together with Cronbach’s alpha providing a test for reliability. Similarity of findings from regression analysis of items in the 4-ISWBI with domains of spiritual well-being in the 20-item SHALOM, as well as partial discrimination by gender, reinforce the validity of the 4-ISWBI as a sound indicator of spiritual well-being and its four domains. In brief, the 4-Item Spiritual Well-Being Index (4-ISWBI) promises to be a handy instrument to aid researchers looking for a convenient, concise, coherent indicator, but not an exhaustive measure, of spiritual well-being. © 2017 by the authors.
- Authors: Fisher, John , Ng, David
- Date: 2017
- Type: Text , Journal article
- Relation: Religions Vol. 8, no. 9 (2017), p. 1-13
- Full Text:
- Reviewed:
- Description: Spiritual well-being is perceived to be reflected in the quality of relationships that people have in four areas, namely with God, others, nature, and self. Many spiritual well-being questionnaires exist, but not many provide an adequate assessment of these four relationships. As part of a survey of parental perceptions of holistic early childhood education in kindergartens in Hong Kong, 1383 parents and 165 teachers, from 22 kindergartens, completed a written survey questionnaire which helped to investigate the potential for a single question with four parts to provide a valid and reliable measure for spiritual well-being. Face, content, and construct validity were confirmed, together with Cronbach’s alpha providing a test for reliability. Similarity of findings from regression analysis of items in the 4-ISWBI with domains of spiritual well-being in the 20-item SHALOM, as well as partial discrimination by gender, reinforce the validity of the 4-ISWBI as a sound indicator of spiritual well-being and its four domains. In brief, the 4-Item Spiritual Well-Being Index (4-ISWBI) promises to be a handy instrument to aid researchers looking for a convenient, concise, coherent indicator, but not an exhaustive measure, of spiritual well-being. © 2017 by the authors.