A computer-aided unit process sustainable modelling for manufacturing processes : Case for extrusion process
- Singh, Karmjit, Sultan, Ibrahim
- Authors: Singh, Karmjit , Sultan, Ibrahim
- Date: 2019
- Type: Text , Journal article
- Relation: Production and Manufacturing Research-an Open Access Journal Vol. 7, no. 1 (2019), p. 143-160
- Full Text:
- Reviewed:
- Description: Sustainable manufacturing assessment is meant to ensure that products are manufactured such that negative environmental impacts are reduced by conserving energy and managing the use of natural resources as well as ensuring economical soundness for the process. The main objective of this work is to introduce sustainable development methodology/models for manufacturing processes. For this purpose, the paper utilizes background data, develops a computer model and presents detailed case studies. This paper will identify and adopt key performance indicators (KPIs) and utilize these to assess the sustainability of extrusion process and their designs. Different manufacturing parameters such as material types, product specifications and manufacturing tools are considered in the process of measuring sustainability. The proposed computer model is verified with data obtain from actual aluminium extrusion plants.
- Authors: Singh, Karmjit , Sultan, Ibrahim
- Date: 2019
- Type: Text , Journal article
- Relation: Production and Manufacturing Research-an Open Access Journal Vol. 7, no. 1 (2019), p. 143-160
- Full Text:
- Reviewed:
- Description: Sustainable manufacturing assessment is meant to ensure that products are manufactured such that negative environmental impacts are reduced by conserving energy and managing the use of natural resources as well as ensuring economical soundness for the process. The main objective of this work is to introduce sustainable development methodology/models for manufacturing processes. For this purpose, the paper utilizes background data, develops a computer model and presents detailed case studies. This paper will identify and adopt key performance indicators (KPIs) and utilize these to assess the sustainability of extrusion process and their designs. Different manufacturing parameters such as material types, product specifications and manufacturing tools are considered in the process of measuring sustainability. The proposed computer model is verified with data obtain from actual aluminium extrusion plants.
A counterexample to De Pierro's conjecture on the convergence of under-relaxed cyclic projections
- Cominetti, Roberto, Roshchina, Vera, Williamson, Andrew
- Authors: Cominetti, Roberto , Roshchina, Vera , Williamson, Andrew
- Date: 2019
- Type: Text , Journal article , acceptedVersion
- Relation: Optimization Vol. 68, no. 1 (2019), p. 3-12
- Full Text:
- Reviewed:
- Description: The convex feasibility problem consists in finding a point in the intersection of a finite family of closed convex sets. When the intersection is empty, a best compromise is to search for a point that minimizes the sum of the squared distances to the sets. In 2001, de Pierro conjectured that the limit cycles generated by the ε-under-relaxed cyclic projection method converge when ε ↓ 0 towards a least squares solution. While the conjecture has been confirmed under fairly general conditions, we show that it is false in general by constructing a system of three compact convex sets in R3 for which the ε-under-relaxed cycles do not converge. © 2018 Informa UK Limited, trading as Taylor & Francis Group.
- Authors: Cominetti, Roberto , Roshchina, Vera , Williamson, Andrew
- Date: 2019
- Type: Text , Journal article , acceptedVersion
- Relation: Optimization Vol. 68, no. 1 (2019), p. 3-12
- Full Text:
- Reviewed:
- Description: The convex feasibility problem consists in finding a point in the intersection of a finite family of closed convex sets. When the intersection is empty, a best compromise is to search for a point that minimizes the sum of the squared distances to the sets. In 2001, de Pierro conjectured that the limit cycles generated by the ε-under-relaxed cyclic projection method converge when ε ↓ 0 towards a least squares solution. While the conjecture has been confirmed under fairly general conditions, we show that it is false in general by constructing a system of three compact convex sets in R3 for which the ε-under-relaxed cycles do not converge. © 2018 Informa UK Limited, trading as Taylor & Francis Group.
A framework for sustainability performance assessment for manufacturing processes
- Authors: Singh, Karmjit
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Sustainable manufacturing methods make it possible to develop products in ways which minimize negative environmental impacts, conserve energy and save natural resources whilst being economically sound. The concepts of sustainability in manufacturing being are still fairly broad, in scope, and need to be more focused and firmly established at the process, machine or factory levels. This project proposes a structure for manufacturing with a main objective to develop a sustainability framework which encompasses various production processes. Structured information models for the seamless flow of information across the design and manufacturing domains, for selected manufacturing processes, are defined. The thesis work identifies key performance indicators (KPIs) for the assessment of manufacturing sustainability and performs analysis of selected unit manufacturing processes and their sub-processes with the aim of proposing a methodology for determining science-based measurements of the manufacturing processes affecting these KPIs. The theoretical foundations established are then used to develop a model that could evaluate sustainability of selected manufacturing processes and their respective process plans providing a basis for inter-process comparison and selection of the most sustainable process plan. The proposed framework is presented in form of a manufacturing planning computer-based package which is designed to to consider different influencing factors such as product information, part geometry, material related physical and processing properties and the manufacturing equipment operating data. The thesis presents a number of case studies which have been published in international journals. The case studies present estimates of the manufacturing sustainability KPIs for a number of production methods. These estimates have been verified with available shop floor data. The work in the thesis makes it possible to establish manufacturing industry equipped to deal the challenges of the future when sustainability will be the major factor up on which the quality of success will be determined.
- Description: Doctor of Philosophy
- Authors: Singh, Karmjit
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Sustainable manufacturing methods make it possible to develop products in ways which minimize negative environmental impacts, conserve energy and save natural resources whilst being economically sound. The concepts of sustainability in manufacturing being are still fairly broad, in scope, and need to be more focused and firmly established at the process, machine or factory levels. This project proposes a structure for manufacturing with a main objective to develop a sustainability framework which encompasses various production processes. Structured information models for the seamless flow of information across the design and manufacturing domains, for selected manufacturing processes, are defined. The thesis work identifies key performance indicators (KPIs) for the assessment of manufacturing sustainability and performs analysis of selected unit manufacturing processes and their sub-processes with the aim of proposing a methodology for determining science-based measurements of the manufacturing processes affecting these KPIs. The theoretical foundations established are then used to develop a model that could evaluate sustainability of selected manufacturing processes and their respective process plans providing a basis for inter-process comparison and selection of the most sustainable process plan. The proposed framework is presented in form of a manufacturing planning computer-based package which is designed to to consider different influencing factors such as product information, part geometry, material related physical and processing properties and the manufacturing equipment operating data. The thesis presents a number of case studies which have been published in international journals. The case studies present estimates of the manufacturing sustainability KPIs for a number of production methods. These estimates have been verified with available shop floor data. The work in the thesis makes it possible to establish manufacturing industry equipped to deal the challenges of the future when sustainability will be the major factor up on which the quality of success will be determined.
- Description: Doctor of Philosophy
A lightweight integrity protection scheme for low latency smart grid applications
- Jolfaei, Alireza, Kant, Krishna
- Authors: Jolfaei, Alireza , Kant, Krishna
- Date: 2019
- Type: Text , Journal article
- Relation: Computers and Security Vol. 86, no. (2019), p. 471-483
- Full Text:
- Reviewed:
- Description: The substation communication protocol used in smart grid allows the transmission of messages without integrity protection for applications that require very low communication latency. This leaves the real-time measurements taken by phasor measurement units (PMUs) vulnerable to man-in-the-middle attacks, and hence makes high voltage to medium voltage (HV/MV) substations vulnerable to cyber-attacks. In this paper, a lightweight and secure integrity protection algorithm has been proposed to maintain the integrity of PMU data, which fills the missing integrity protection in the IEC 61850-90-5 standard, when the MAC identifier is declared 0. The rigorous security analysis proves the security of the proposed integrity protection method against ciphertext-only attacks and known/chosen plaintext attacks. A comparison with existing integrity protection methods shows that our method is much faster, and is also the only integrity protection scheme that meets the strict timing requirement. Not only the proposed method can be used in power protection applications, but it also can be used in emerging anomaly detection scenarios, where a fast integrity check coupled with low latency communications is used for multiple rounds of message exchanges. This paper is an extension of work originally reported in Proceedings of 14th International Conference on Security and Cryptography (Jolfaei and Kant, 2017).
- Authors: Jolfaei, Alireza , Kant, Krishna
- Date: 2019
- Type: Text , Journal article
- Relation: Computers and Security Vol. 86, no. (2019), p. 471-483
- Full Text:
- Reviewed:
- Description: The substation communication protocol used in smart grid allows the transmission of messages without integrity protection for applications that require very low communication latency. This leaves the real-time measurements taken by phasor measurement units (PMUs) vulnerable to man-in-the-middle attacks, and hence makes high voltage to medium voltage (HV/MV) substations vulnerable to cyber-attacks. In this paper, a lightweight and secure integrity protection algorithm has been proposed to maintain the integrity of PMU data, which fills the missing integrity protection in the IEC 61850-90-5 standard, when the MAC identifier is declared 0. The rigorous security analysis proves the security of the proposed integrity protection method against ciphertext-only attacks and known/chosen plaintext attacks. A comparison with existing integrity protection methods shows that our method is much faster, and is also the only integrity protection scheme that meets the strict timing requirement. Not only the proposed method can be used in power protection applications, but it also can be used in emerging anomaly detection scenarios, where a fast integrity check coupled with low latency communications is used for multiple rounds of message exchanges. This paper is an extension of work originally reported in Proceedings of 14th International Conference on Security and Cryptography (Jolfaei and Kant, 2017).
A quadtree-polygon-based scaled boundary finite element method for image-based mesoscale fracture modelling in concrete
- Guo, H., Ooi, Ean Tat, Saputra, Albert, Yang, Zhenjun, Natarajan, Sundararajan, Ooi, Ean Hin, Song, Chongmin
- Authors: Guo, H. , Ooi, Ean Tat , Saputra, Albert , Yang, Zhenjun , Natarajan, Sundararajan , Ooi, Ean Hin , Song, Chongmin
- Date: 2019
- Type: Text , Journal article , acceptedVersion
- Relation: Engineering Fracture Mechanics Vol. 211, no. (2019), p. 420-441
- Full Text:
- Reviewed:
- Description: A quadtree-polygon scaled boundary finite element-based approach for image-based modelling of concrete fracture at the mesoscale is developed. Digital images representing the two-phase mesostructure of concrete, which comprises of coarse aggregates and mortar are either generated using a take-and-place algorithm with a user-defined aggregate volume ratio or obtained from X-ray computed tomography as an input. The digital images are automatically discretised for analysis by applying a balanced quadtree decomposition in combination with a smoothing operation. The scaled boundary finite element method is applied to model the constituents in the concrete mesostructure. A quadtree formulation within the framework of the scaled boundary finite element method is advantageous in that the displacement compatibility between the cells are automatically preserved even in the presence of hanging nodes. Moreover, the geometric flexibility of the scaled boundary finite element method facilitates the use of arbitrary sided polygons, allowing better representation of the aggregate boundaries. The computational burden is significantly reduced as there are only finite number of cell types in a balanced quadtree mesh. The cells in the mesh are connected to each other using cohesive interface elements with appropriate softening laws to model the fracture of the mesostructure. Parametric studies are carried out on concrete specimens subjected to uniaxial tension to investigate the effects of various parameters e.g. aggregate size distribution, porosity and aggregate volume ratio on the fracture of concrete at the meso-scale. Mesoscale fracture of concrete specimens obtained from X-ray computed tomography scans are carried out to demonstrate its feasibility.
- Authors: Guo, H. , Ooi, Ean Tat , Saputra, Albert , Yang, Zhenjun , Natarajan, Sundararajan , Ooi, Ean Hin , Song, Chongmin
- Date: 2019
- Type: Text , Journal article , acceptedVersion
- Relation: Engineering Fracture Mechanics Vol. 211, no. (2019), p. 420-441
- Full Text:
- Reviewed:
- Description: A quadtree-polygon scaled boundary finite element-based approach for image-based modelling of concrete fracture at the mesoscale is developed. Digital images representing the two-phase mesostructure of concrete, which comprises of coarse aggregates and mortar are either generated using a take-and-place algorithm with a user-defined aggregate volume ratio or obtained from X-ray computed tomography as an input. The digital images are automatically discretised for analysis by applying a balanced quadtree decomposition in combination with a smoothing operation. The scaled boundary finite element method is applied to model the constituents in the concrete mesostructure. A quadtree formulation within the framework of the scaled boundary finite element method is advantageous in that the displacement compatibility between the cells are automatically preserved even in the presence of hanging nodes. Moreover, the geometric flexibility of the scaled boundary finite element method facilitates the use of arbitrary sided polygons, allowing better representation of the aggregate boundaries. The computational burden is significantly reduced as there are only finite number of cell types in a balanced quadtree mesh. The cells in the mesh are connected to each other using cohesive interface elements with appropriate softening laws to model the fracture of the mesostructure. Parametric studies are carried out on concrete specimens subjected to uniaxial tension to investigate the effects of various parameters e.g. aggregate size distribution, porosity and aggregate volume ratio on the fracture of concrete at the meso-scale. Mesoscale fracture of concrete specimens obtained from X-ray computed tomography scans are carried out to demonstrate its feasibility.
A simulated annealing-based maximum-margin clustering algorithm
- Seifollahi, Sattar, Bagirov, Adil, Borzeshi, Ehsan, Piccardi, Massimo
- Authors: Seifollahi, Sattar , Bagirov, Adil , Borzeshi, Ehsan , Piccardi, Massimo
- Date: 2019
- Type: Text , Journal article
- Relation: Computational Intelligence Vol. 35, no. 1 (2019), p. 23-41
- Full Text:
- Reviewed:
- Description: Maximum-margin clustering is an extension of the support vector machine (SVM) to clustering. It partitions a set of unlabeled data into multiple groups by finding hyperplanes with the largest margins. Although existing algorithms have shown promising results, there is no guarantee of convergence of these algorithms to global solutions due to the nonconvexity of the optimization problem. In this paper, we propose a simulated annealing-based algorithm that is able to mitigate the issue of local minima in the maximum-margin clustering problem. The novelty of our algorithm is twofold, ie, (i) it comprises a comprehensive cluster modification scheme based on simulated annealing, and (ii) it introduces a new approach based on the combination of k-means++ and SVM at each step of the annealing process. More precisely, k-means++ is initially applied to extract subsets of the data points. Then, an unsupervised SVM is applied to improve the clustering results. Experimental results on various benchmark data sets (of up to over a million points) give evidence that the proposed algorithm is more effective at solving the clustering problem than a number of popular clustering algorithms.
- Authors: Seifollahi, Sattar , Bagirov, Adil , Borzeshi, Ehsan , Piccardi, Massimo
- Date: 2019
- Type: Text , Journal article
- Relation: Computational Intelligence Vol. 35, no. 1 (2019), p. 23-41
- Full Text:
- Reviewed:
- Description: Maximum-margin clustering is an extension of the support vector machine (SVM) to clustering. It partitions a set of unlabeled data into multiple groups by finding hyperplanes with the largest margins. Although existing algorithms have shown promising results, there is no guarantee of convergence of these algorithms to global solutions due to the nonconvexity of the optimization problem. In this paper, we propose a simulated annealing-based algorithm that is able to mitigate the issue of local minima in the maximum-margin clustering problem. The novelty of our algorithm is twofold, ie, (i) it comprises a comprehensive cluster modification scheme based on simulated annealing, and (ii) it introduces a new approach based on the combination of k-means++ and SVM at each step of the annealing process. More precisely, k-means++ is initially applied to extract subsets of the data points. Then, an unsupervised SVM is applied to improve the clustering results. Experimental results on various benchmark data sets (of up to over a million points) give evidence that the proposed algorithm is more effective at solving the clustering problem than a number of popular clustering algorithms.
A topological group observation on the Banach-Mazur separable quotient problem
- Gabriyelyan, Saak, Morris, Sidney
- Authors: Gabriyelyan, Saak , Morris, Sidney
- Date: 2019
- Type: Text , Journal article
- Relation: Topology and Its Applications Vol. 259, no. (2019), p. 283-286
- Full Text:
- Reviewed:
- Description: The Separable Quotient Problem of Banach and Mazur asks if every infinite-dimensional Banach space has an infinite-dimensional separable quotient Banach space. It has remained unsolved for 85 years but has been answered in the affirmative for special cases such as reflexive Banach spaces. An affirmative answer to the Separable Quotient Problem would obviously imply that every infinite-dimensional Banach space has a quotient topological group which is separable, metrizable, and infinite-dimensional in the sense of topology. In this paper it is proved that every infinite-dimensional Banach space has as a quotient group the separable metrizable infinite-dimensional topological group, T
- Authors: Gabriyelyan, Saak , Morris, Sidney
- Date: 2019
- Type: Text , Journal article
- Relation: Topology and Its Applications Vol. 259, no. (2019), p. 283-286
- Full Text:
- Reviewed:
- Description: The Separable Quotient Problem of Banach and Mazur asks if every infinite-dimensional Banach space has an infinite-dimensional separable quotient Banach space. It has remained unsolved for 85 years but has been answered in the affirmative for special cases such as reflexive Banach spaces. An affirmative answer to the Separable Quotient Problem would obviously imply that every infinite-dimensional Banach space has a quotient topological group which is separable, metrizable, and infinite-dimensional in the sense of topology. In this paper it is proved that every infinite-dimensional Banach space has as a quotient group the separable metrizable infinite-dimensional topological group, T
Aerobic training protects cardiac function during advancing age : A meta-analysis of four decades of controlled studies
- Beaumont, Alexander, Grace, Fergal, Richards, Joanna, Campbell, Amy, Sculthorpe, Nicholas
- Authors: Beaumont, Alexander , Grace, Fergal , Richards, Joanna , Campbell, Amy , Sculthorpe, Nicholas
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 49, no. 2 (2019), p. 199-219
- Full Text:
- Reviewed:
- Description: Background: In contrast to younger athletes, there is comparatively less literature examining cardiac structure and function in older athletes. However, a progressive accumulation of studies during the past four decades offers a body of literature worthy of systematic scrutiny. Objectives: We conducted a systematic review, meta-analysis and meta-regression of controlled echocardiography studies comparing left ventricular (LV) structure and function in aerobically trained older athletes (> 45 years) with age-matched untrained controls, in addition to investigating the influence of chronological age. Methods: Electronic databases were searched from inception to January 2018 before conducting a random-effects meta-analysis to calculate pooled differences in means, effect size and 95% confidence intervals (CIs). Study heterogeneity was reported using Cochran’s Q and I2 statistic. Results: Overall, 32 studies (644 athletes; 582 controls) were included. Athletes had greater LV end-diastolic diameter (3.65 mm, 95% CI 2.66–4.64), interventricular septal thickness (1.23 mm, 95% CI 0.85–1.60), posterior wall thickness (1.20 mm, 95% CI 0.83–1.56), LV mass (72 g, 95% CI 46–98), LV mass index (28.17 g·m2, 95% CI 19.84–36.49) and stroke volume (13.59 mL, 95% CI 7.20–19.98) (all p < 0.01). Athletes had superior global diastolic function [ratio of early (E) to late (A) mitral inflow velocity (E/A) 0.18, 95% CI 0.13–0.24, p < 0.01; ratio of early (e′) to late (a′) diastolic annular tissue velocity (e′/a′) 0.23, 95% CI 0.06–0.40, p = 0.01], lower A (−8.20 cm·s−1, 95% CI −11.90 to −4.51, p < 0.01) and a′ (−0.72 cm·s−1, 95% CI −1.31 to −0.12, p = 0.02), and more rapid e′ (0.96 cm·s−1, 95% CI 0.05–1.86, p = 0.04). Meta-regression for chronological age identified that athlete–control differences, in the main, are maintained during advancing age. Conclusions: Athletic older men have larger cardiac dimensions and enjoy more favourable cardiac function than healthy, non-athletic counterparts. Notably, the athlete groups maintain these effects during chronological ageing. © 2018, The Author(s).
- Authors: Beaumont, Alexander , Grace, Fergal , Richards, Joanna , Campbell, Amy , Sculthorpe, Nicholas
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 49, no. 2 (2019), p. 199-219
- Full Text:
- Reviewed:
- Description: Background: In contrast to younger athletes, there is comparatively less literature examining cardiac structure and function in older athletes. However, a progressive accumulation of studies during the past four decades offers a body of literature worthy of systematic scrutiny. Objectives: We conducted a systematic review, meta-analysis and meta-regression of controlled echocardiography studies comparing left ventricular (LV) structure and function in aerobically trained older athletes (> 45 years) with age-matched untrained controls, in addition to investigating the influence of chronological age. Methods: Electronic databases were searched from inception to January 2018 before conducting a random-effects meta-analysis to calculate pooled differences in means, effect size and 95% confidence intervals (CIs). Study heterogeneity was reported using Cochran’s Q and I2 statistic. Results: Overall, 32 studies (644 athletes; 582 controls) were included. Athletes had greater LV end-diastolic diameter (3.65 mm, 95% CI 2.66–4.64), interventricular septal thickness (1.23 mm, 95% CI 0.85–1.60), posterior wall thickness (1.20 mm, 95% CI 0.83–1.56), LV mass (72 g, 95% CI 46–98), LV mass index (28.17 g·m2, 95% CI 19.84–36.49) and stroke volume (13.59 mL, 95% CI 7.20–19.98) (all p < 0.01). Athletes had superior global diastolic function [ratio of early (E) to late (A) mitral inflow velocity (E/A) 0.18, 95% CI 0.13–0.24, p < 0.01; ratio of early (e′) to late (a′) diastolic annular tissue velocity (e′/a′) 0.23, 95% CI 0.06–0.40, p = 0.01], lower A (−8.20 cm·s−1, 95% CI −11.90 to −4.51, p < 0.01) and a′ (−0.72 cm·s−1, 95% CI −1.31 to −0.12, p = 0.02), and more rapid e′ (0.96 cm·s−1, 95% CI 0.05–1.86, p = 0.04). Meta-regression for chronological age identified that athlete–control differences, in the main, are maintained during advancing age. Conclusions: Athletic older men have larger cardiac dimensions and enjoy more favourable cardiac function than healthy, non-athletic counterparts. Notably, the athlete groups maintain these effects during chronological ageing. © 2018, The Author(s).
An efficient RANSAC hypothesis evaluation using sufficient statistics for RGB-D pose estimation
- Senthooran, Ilankalkone, Murshed, Manzur, Barca, Jan, Kamruzzaman, Joarder, Chung, Hoam
- Authors: Senthooran, Ilankalkone , Murshed, Manzur , Barca, Jan , Kamruzzaman, Joarder , Chung, Hoam
- Date: 2019
- Type: Text , Journal article
- Relation: Autonomous Robots Vol. 43, no. 5 (2019), p. 1257-1270
- Full Text:
- Reviewed:
- Description: Achieving autonomous flight in GPS-denied environments begins with pose estimation in three-dimensional space, and this is much more challenging in an MAV in a swarm robotic system due to limited computational resources. In vision-based pose estimation, outlier detection is the most time-consuming step. This usually involves a RANSAC procedure using the reprojection-error method for hypothesis evaluation. Realignment-based hypothesis evaluation method is observed to be more accurate, but the considerably slower speed makes it unsuitable for robots with limited resources. We use sufficient statistics of least-squares minimisation to speed up this process. The additive nature of these sufficient statistics makes it possible to compute pose estimates in each evaluation by reusing previously computed statistics. Thus estimates need not be calculated from scratch each time. The proposed method is tested on standard RANSAC, Preemptive RANSAC and R-RANSAC using benchmark datasets. The results show that the use of sufficient statistics speeds up the outlier detection process with realignment hypothesis evaluation for all RANSAC variants, achieving an execution speed of up to 6.72 times.
- Authors: Senthooran, Ilankalkone , Murshed, Manzur , Barca, Jan , Kamruzzaman, Joarder , Chung, Hoam
- Date: 2019
- Type: Text , Journal article
- Relation: Autonomous Robots Vol. 43, no. 5 (2019), p. 1257-1270
- Full Text:
- Reviewed:
- Description: Achieving autonomous flight in GPS-denied environments begins with pose estimation in three-dimensional space, and this is much more challenging in an MAV in a swarm robotic system due to limited computational resources. In vision-based pose estimation, outlier detection is the most time-consuming step. This usually involves a RANSAC procedure using the reprojection-error method for hypothesis evaluation. Realignment-based hypothesis evaluation method is observed to be more accurate, but the considerably slower speed makes it unsuitable for robots with limited resources. We use sufficient statistics of least-squares minimisation to speed up this process. The additive nature of these sufficient statistics makes it possible to compute pose estimates in each evaluation by reusing previously computed statistics. Thus estimates need not be calculated from scratch each time. The proposed method is tested on standard RANSAC, Preemptive RANSAC and R-RANSAC using benchmark datasets. The results show that the use of sufficient statistics speeds up the outlier detection process with realignment hypothesis evaluation for all RANSAC variants, achieving an execution speed of up to 6.72 times.
An efficient selective miner consensus protocol in blockchain oriented iot smart monitoring
- Uddin, Ashraf, Stranieri, Andrew, Gondal, Iqbal, Balasubramanian, Venki
- Authors: Uddin, Ashraf , Stranieri, Andrew , Gondal, Iqbal , Balasubramanian, Venki
- Date: 2019
- Type: Text , Conference proceedings , Conference Paper
- Relation: 2019 IEEE International Conference on Industrial Technology, ICIT 2019; Melbourne; Australia; 13th-15th February 2019 Vol. 2019-February, p. 1135-1142
- Full Text:
- Reviewed:
- Description: Blockchains have been widely used in Internet of Things(IoT) applications including smart cities, smart home and smart governance to provide high levels of security and privacy. In this article, we advance a Blockchain based decentralized architecture for the storage of IoT data produced from smart home/cities. The architecture includes a secure communication protocol using a sign-encryption technique between power constrained IoT devices and a Gateway. The sign encryption also preserves privacy. We propose that a Software Agent executing on the Gateway selects a Miner node using performance parameters of Miners. Simulations demonstrate that the recommended Miner selection outperforms Proof of Works selection used in Bitcoin and Random Miner Selection.
- Description: Proceedings of the IEEE International Conference on Industrial Technology
- Authors: Uddin, Ashraf , Stranieri, Andrew , Gondal, Iqbal , Balasubramanian, Venki
- Date: 2019
- Type: Text , Conference proceedings , Conference Paper
- Relation: 2019 IEEE International Conference on Industrial Technology, ICIT 2019; Melbourne; Australia; 13th-15th February 2019 Vol. 2019-February, p. 1135-1142
- Full Text:
- Reviewed:
- Description: Blockchains have been widely used in Internet of Things(IoT) applications including smart cities, smart home and smart governance to provide high levels of security and privacy. In this article, we advance a Blockchain based decentralized architecture for the storage of IoT data produced from smart home/cities. The architecture includes a secure communication protocol using a sign-encryption technique between power constrained IoT devices and a Gateway. The sign encryption also preserves privacy. We propose that a Software Agent executing on the Gateway selects a Miner node using performance parameters of Miners. Simulations demonstrate that the recommended Miner selection outperforms Proof of Works selection used in Bitcoin and Random Miner Selection.
- Description: Proceedings of the IEEE International Conference on Industrial Technology
Atmospheric CO₂ Concentration and Other Limiting Factors in the Growth of C₃ and C₄ Plants
- Boretti, Albert, Florentine, Singarayer
- Authors: Boretti, Albert , Florentine, Singarayer
- Date: 2019
- Type: Text , Journal article
- Relation: Plants Vol. 8, no. 4 (2019), p. 1-11
- Full Text:
- Reviewed:
- Description: It has been widely observed that recent increases in atmospheric CO2 concentrations have had, so far, a positive effect on the growth of plants. This is not surprising since CO2 is an important nutrient for plant matter, being directly involved in photosynthesis. However, it is also known that the conditions which have accompanied this increase in atmospheric CO2 concentration have also had significant effects on other environmental factors. It is possible that these other effects may emerge as limiting factors which could act to prevent plant growth. This may involve complex interactions between prevailing sunlight and water conditions, variable temperatures, the availability of essential nutrients and the type of synthetic pathway for the plant species. The issue of concern to this investigation is if we should be worried about a possible shift in the C3-C4 paradigm driven by changes in the atmospheric CO2 concentration, or if some other factor, such as water scarcity, is much more relevant within a 30-year time frame. If an opinion is needed on what will have the worst effect on the survival of the planet between the scarcity of water or the reduced efficiency of C3 plants to sequester CO2, the issue of water is the more incisive.
- Authors: Boretti, Albert , Florentine, Singarayer
- Date: 2019
- Type: Text , Journal article
- Relation: Plants Vol. 8, no. 4 (2019), p. 1-11
- Full Text:
- Reviewed:
- Description: It has been widely observed that recent increases in atmospheric CO2 concentrations have had, so far, a positive effect on the growth of plants. This is not surprising since CO2 is an important nutrient for plant matter, being directly involved in photosynthesis. However, it is also known that the conditions which have accompanied this increase in atmospheric CO2 concentration have also had significant effects on other environmental factors. It is possible that these other effects may emerge as limiting factors which could act to prevent plant growth. This may involve complex interactions between prevailing sunlight and water conditions, variable temperatures, the availability of essential nutrients and the type of synthetic pathway for the plant species. The issue of concern to this investigation is if we should be worried about a possible shift in the C3-C4 paradigm driven by changes in the atmospheric CO2 concentration, or if some other factor, such as water scarcity, is much more relevant within a 30-year time frame. If an opinion is needed on what will have the worst effect on the survival of the planet between the scarcity of water or the reduced efficiency of C3 plants to sequester CO2, the issue of water is the more incisive.
Barriers and enablers to women's access to services during childbearing in Timor-Leste
- Authors: King, Rosemary
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Background: In Timor-Leste the maternal mortality ratio (MMR) is one of the highest in Southeast Asia, in some districts only 15-25% of women birth in a facility with a skilled birth attendant (SBA). Care from SBA is the international benchmark for quality maternity care. Purpose: Determine the barriers and enablers to women's access to services during childbearing in Timor-Leste, including women’s expectations and needs. Methodology: Qualitative research using focused ethnography, data collection methods included semi-structured interviews, focus groups and participant observation. Seventeen stakeholders and thirty women from three districts in Timor-Leste participated. Thematic analysis and coding of data with triangulation of the findings between separate participant groups. Results: Barriers to woman’s access to SBA include poor roads, lack of transport, costs associated with accessing SBA, lack of availability and poor quality services. Lack of privacy, multiple care-givers and poor interpersonal communication from SBA were also noted. Stakeholders emphasise health promotion and antenatal care to counteract the influence of traditional beliefs and promote demand for SBA. Many women demonstrate their agency in health seeking behaviours and choices for care during pregnancy and childbirth. Discussion: Women understand that pregnancy and childbirth poses potential risks to their health. Rural women, women from low socio-economic and other marginalised groups have less access to services. Perceptions of poor quality services also reduce women’s demand. Conclusion: Barriers and enablers to woman’s access to services are identified using an amended AAAQ framework introducing the domain of Antecedents in addition to domains of Access, Availability, Acceptability and Quality (AAAQA). Further expenditure on health service infrastructure, staff training and community outreach will improve access and quality SBA. Culturally safe SBA services may also improve the uptake of SBA service in Timor-Leste. Key words: Timor-Leste, Skilled birth attendance, cultural safety, women’s agency, quality maternity care.
- Description: Doctor of Philosophy
- Authors: King, Rosemary
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Background: In Timor-Leste the maternal mortality ratio (MMR) is one of the highest in Southeast Asia, in some districts only 15-25% of women birth in a facility with a skilled birth attendant (SBA). Care from SBA is the international benchmark for quality maternity care. Purpose: Determine the barriers and enablers to women's access to services during childbearing in Timor-Leste, including women’s expectations and needs. Methodology: Qualitative research using focused ethnography, data collection methods included semi-structured interviews, focus groups and participant observation. Seventeen stakeholders and thirty women from three districts in Timor-Leste participated. Thematic analysis and coding of data with triangulation of the findings between separate participant groups. Results: Barriers to woman’s access to SBA include poor roads, lack of transport, costs associated with accessing SBA, lack of availability and poor quality services. Lack of privacy, multiple care-givers and poor interpersonal communication from SBA were also noted. Stakeholders emphasise health promotion and antenatal care to counteract the influence of traditional beliefs and promote demand for SBA. Many women demonstrate their agency in health seeking behaviours and choices for care during pregnancy and childbirth. Discussion: Women understand that pregnancy and childbirth poses potential risks to their health. Rural women, women from low socio-economic and other marginalised groups have less access to services. Perceptions of poor quality services also reduce women’s demand. Conclusion: Barriers and enablers to woman’s access to services are identified using an amended AAAQ framework introducing the domain of Antecedents in addition to domains of Access, Availability, Acceptability and Quality (AAAQA). Further expenditure on health service infrastructure, staff training and community outreach will improve access and quality SBA. Culturally safe SBA services may also improve the uptake of SBA service in Timor-Leste. Key words: Timor-Leste, Skilled birth attendance, cultural safety, women’s agency, quality maternity care.
- Description: Doctor of Philosophy
Bayes, time perception, and relativity : The central role of hopelessness
- Kent, Lachlan, Van Doorn, George, Hohwy, Jakob, Klein, Britt
- Authors: Kent, Lachlan , Van Doorn, George , Hohwy, Jakob , Klein, Britt
- Date: 2019
- Type: Text , Journal article
- Relation: Consciousness and Cognition Vol. 69, no. (2019), p. 70-80
- Full Text:
- Reviewed:
- Description: Time judgement and time experience are distinct elements of time perception. It is known that time experience tends to be slow, or dilated, when depressed, but there is less certainty or clarity concerning how depression affects time judgement. Here, we use a Bayesian Prediction Error Minimisation (PEM) framework called 'distrusting the present' as an explanatory and predictive model of both aspects of time perception. An interval production task was designed to probe and modulate the relationship between time perception and depression. Results showed that hopelessness, a symptom of severe depression, was associated with the ordering of interval lengths, reduced overall error, and dilated time experience. We propose that 'distrusting the future' is accompanied by 'trusting the present', leading to the experiences of time dilation when depressed or hopeless. Evidence was also found to support a relative difference model of how hopelessness dilates, and arousal accelerates, the rate of experienced time.
- Authors: Kent, Lachlan , Van Doorn, George , Hohwy, Jakob , Klein, Britt
- Date: 2019
- Type: Text , Journal article
- Relation: Consciousness and Cognition Vol. 69, no. (2019), p. 70-80
- Full Text:
- Reviewed:
- Description: Time judgement and time experience are distinct elements of time perception. It is known that time experience tends to be slow, or dilated, when depressed, but there is less certainty or clarity concerning how depression affects time judgement. Here, we use a Bayesian Prediction Error Minimisation (PEM) framework called 'distrusting the present' as an explanatory and predictive model of both aspects of time perception. An interval production task was designed to probe and modulate the relationship between time perception and depression. Results showed that hopelessness, a symptom of severe depression, was associated with the ordering of interval lengths, reduced overall error, and dilated time experience. We propose that 'distrusting the future' is accompanied by 'trusting the present', leading to the experiences of time dilation when depressed or hopeless. Evidence was also found to support a relative difference model of how hopelessness dilates, and arousal accelerates, the rate of experienced time.
Binge eating in patients with polycystic ovary syndrome : Prevalence, causes, and management strategies
- Krug, Isabel, Giles, Sarah, Paganini, Chiara
- Authors: Krug, Isabel , Giles, Sarah , Paganini, Chiara
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Neuropsychiatric Disease and Treatment Vol. 15, no. (2019), p. 1273-1285
- Full Text:
- Reviewed:
- Description: Emerging evidence suggests that disordered eating, particularly binge-eating symptomatology, is overrepresented within Polycystic Ovary Syndrome (PCOS) populations. This comorbidity presents a clinical dilemma as current treatment approaches for PCOS emphasize the importance of weight management, diet, exercise, and the potential for harm of such treatment approaches in PCOS patients with comorbid disordered eating. However, limited research has assessed the occurrence of binge eating and disordered eating in PCOS patients. Consequently, little is known about the prevalence of binge eating in PCOS, and the possible etiological processes to explain this comorbidity remain poorly understood. Given the paucity of research on this topic, the aims of this narrative review are fourfold: 1) to outline the main symptoms of PCOS and binge eating; 2) to provide an overview of the prevalence of binge eating in PCOS; 3) to outline possible etiological factors for the comorbidity between PCOS and binge eating; and 4) to provide an overview of management strategies of binge eating in PCOS.
- Authors: Krug, Isabel , Giles, Sarah , Paganini, Chiara
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Neuropsychiatric Disease and Treatment Vol. 15, no. (2019), p. 1273-1285
- Full Text:
- Reviewed:
- Description: Emerging evidence suggests that disordered eating, particularly binge-eating symptomatology, is overrepresented within Polycystic Ovary Syndrome (PCOS) populations. This comorbidity presents a clinical dilemma as current treatment approaches for PCOS emphasize the importance of weight management, diet, exercise, and the potential for harm of such treatment approaches in PCOS patients with comorbid disordered eating. However, limited research has assessed the occurrence of binge eating and disordered eating in PCOS patients. Consequently, little is known about the prevalence of binge eating in PCOS, and the possible etiological processes to explain this comorbidity remain poorly understood. Given the paucity of research on this topic, the aims of this narrative review are fourfold: 1) to outline the main symptoms of PCOS and binge eating; 2) to provide an overview of the prevalence of binge eating in PCOS; 3) to outline possible etiological factors for the comorbidity between PCOS and binge eating; and 4) to provide an overview of management strategies of binge eating in PCOS.
Biochar versus bone char for a sustainable inorganic arsenic mitigation in water : What needs to be done in future research?
- Alkurdi, Susan, Herath, Indika, Bundschuh, Jochen, Al-Juboori, Raed, Vithanage, Meththika, Mohan, Dinesh
- Authors: Alkurdi, Susan , Herath, Indika , Bundschuh, Jochen , Al-Juboori, Raed , Vithanage, Meththika , Mohan, Dinesh
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Environment International Vol. 127, no. (2019), p. 52-69
- Full Text:
- Reviewed:
- Description: Arsenic (As) is an emerging contaminant on a global scale posing threat to environmental and human health. The relatively brief history of the applications of biochar and bone char has mapped the endeavors to remove As from water to a considerable extent. This critical review attempts to provide a comprehensive overview for the first time on the potential of bio- and bone-char in the immobilization of inorganic As in water. It seeks to offer a rational assessment of what is existing and what needs to be done in future research as an implication for As toxicity of human health risks through acute and chronic exposure to As contaminated water. Bio- and bone-char are recognized as promising alternatives to activated carbon due to their lower production and activation cost. The surface modification via chemical methods has been adopted to improve the adsorption capacity for anionic As species. Surface complexation, ion exchange, precipitation and electrostatic interactions are the main mechanisms involved in the adsorption of As onto the char surface. However, arsenic-bio-bone char interactions along with their chemical bonding for the removal of As in aqueous solution is still a subject of debate. Hence, the proposed mechanisms need to be scrutinized further using advanced analytical techniques such as synchrotron-based X-ray. Moving this technology from laboratory phase to field scale applications is an urgent necessity in order to establish a sustainable As mitigation in drinking water on a global scale.
- Authors: Alkurdi, Susan , Herath, Indika , Bundschuh, Jochen , Al-Juboori, Raed , Vithanage, Meththika , Mohan, Dinesh
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Environment International Vol. 127, no. (2019), p. 52-69
- Full Text:
- Reviewed:
- Description: Arsenic (As) is an emerging contaminant on a global scale posing threat to environmental and human health. The relatively brief history of the applications of biochar and bone char has mapped the endeavors to remove As from water to a considerable extent. This critical review attempts to provide a comprehensive overview for the first time on the potential of bio- and bone-char in the immobilization of inorganic As in water. It seeks to offer a rational assessment of what is existing and what needs to be done in future research as an implication for As toxicity of human health risks through acute and chronic exposure to As contaminated water. Bio- and bone-char are recognized as promising alternatives to activated carbon due to their lower production and activation cost. The surface modification via chemical methods has been adopted to improve the adsorption capacity for anionic As species. Surface complexation, ion exchange, precipitation and electrostatic interactions are the main mechanisms involved in the adsorption of As onto the char surface. However, arsenic-bio-bone char interactions along with their chemical bonding for the removal of As in aqueous solution is still a subject of debate. Hence, the proposed mechanisms need to be scrutinized further using advanced analytical techniques such as synchrotron-based X-ray. Moving this technology from laboratory phase to field scale applications is an urgent necessity in order to establish a sustainable As mitigation in drinking water on a global scale.
Bone char as a green sorbent for removing health threatening fluoride from drinking water
- Alkurdi, Susan, Al-Juboori, Raed, Bundschuh, Jochen, Hamawand, Ihsan
- Authors: Alkurdi, Susan , Al-Juboori, Raed , Bundschuh, Jochen , Hamawand, Ihsan
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Environment International Vol. 127, no. (2019), p. 704-719
- Full Text:
- Reviewed:
- Description: Millions of people around the world suffer from or prone to health problems caused by high concentration of fluoride in drinking water sources. One of the environmentally friendly and cost-effective ways for removing fluoride is the use of bone char. In this review, the structural properties and binding affinity of fluoride ions from different water sources was critically discussed. The effect of experimental conditions on enhancing the adsorption capacity of fluoride ions using bone char samples was addressed. It appears that surface properties, and conditions of the bone char production such as temperature and residence time play an important role in designing the optimal fluoride removal process. The optimum temperature for fluoride removal seems to be in the range of 500–700 °C and a residence time of 2 h. Applying various equilibrium adsorption isotherms for understanding fluoride adsorption mechanism was presented. The effect of bone char modification with different elements were discussed and recommendations for a further increase in the removal efficiency was proposed. Cost of bone char production and large-scale treatment systems were also discussed based on information available from scientific and commercial sources. Challenges with existing domestic defluoridation designs were highlighted and suggestions for new conceptual designs were provided.
- Authors: Alkurdi, Susan , Al-Juboori, Raed , Bundschuh, Jochen , Hamawand, Ihsan
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Environment International Vol. 127, no. (2019), p. 704-719
- Full Text:
- Reviewed:
- Description: Millions of people around the world suffer from or prone to health problems caused by high concentration of fluoride in drinking water sources. One of the environmentally friendly and cost-effective ways for removing fluoride is the use of bone char. In this review, the structural properties and binding affinity of fluoride ions from different water sources was critically discussed. The effect of experimental conditions on enhancing the adsorption capacity of fluoride ions using bone char samples was addressed. It appears that surface properties, and conditions of the bone char production such as temperature and residence time play an important role in designing the optimal fluoride removal process. The optimum temperature for fluoride removal seems to be in the range of 500–700 °C and a residence time of 2 h. Applying various equilibrium adsorption isotherms for understanding fluoride adsorption mechanism was presented. The effect of bone char modification with different elements were discussed and recommendations for a further increase in the removal efficiency was proposed. Cost of bone char production and large-scale treatment systems were also discussed based on information available from scientific and commercial sources. Challenges with existing domestic defluoridation designs were highlighted and suggestions for new conceptual designs were provided.
Changes in lower body muscular performance following a season of NCAA Division I Men's Lacrosse
- Talpey, Scott, Axtell, Robert, Gardner, Elizabeth, James, Lachlan
- Authors: Talpey, Scott , Axtell, Robert , Gardner, Elizabeth , James, Lachlan
- Date: 2019
- Type: Text , Journal article
- Relation: Sports Vol. 7, no. 1 (2019), p. 1-12
- Full Text:
- Reviewed:
- Description: The tactical and technical components of training become a primary emphasis, leaving less time for targeted development of physical qualities that underpin performance during the competition phase of a training program. A deemphasis on physical preparation during the in-season training phase may make athletes more susceptible to injury and decrease performance on the field. Two weeks prior to the start and one week following the conclusion of the 16-week collegiate lacrosse season, lower body force production was assessed in eight National Collegiate Athletic Association (NCAA) Division I Men's Lacrosse athletes. Lower body force production capabilities were determined via the performance of countermovement jumps (CMJ) and drop jumps (DJ) performed on a force plate and isokinetic strength testing of the quadriceps and hamstring muscle groups across three velocities. Isokinetic strength of the hamstrings and the hamstring to quadriceps strength ratio were maintained or increased over the course of the competition phase of training. Relative peak force obtained from the CMJ and the reactive strength index from the DJ decreased significantly over the season. The maintenance of isokinetic strength and the decrease in CMJ and DJ performance may indicate the presence of neuromuscular fatigue that accumulated over the course of the season.
- Authors: Talpey, Scott , Axtell, Robert , Gardner, Elizabeth , James, Lachlan
- Date: 2019
- Type: Text , Journal article
- Relation: Sports Vol. 7, no. 1 (2019), p. 1-12
- Full Text:
- Reviewed:
- Description: The tactical and technical components of training become a primary emphasis, leaving less time for targeted development of physical qualities that underpin performance during the competition phase of a training program. A deemphasis on physical preparation during the in-season training phase may make athletes more susceptible to injury and decrease performance on the field. Two weeks prior to the start and one week following the conclusion of the 16-week collegiate lacrosse season, lower body force production was assessed in eight National Collegiate Athletic Association (NCAA) Division I Men's Lacrosse athletes. Lower body force production capabilities were determined via the performance of countermovement jumps (CMJ) and drop jumps (DJ) performed on a force plate and isokinetic strength testing of the quadriceps and hamstring muscle groups across three velocities. Isokinetic strength of the hamstrings and the hamstring to quadriceps strength ratio were maintained or increased over the course of the competition phase of training. Relative peak force obtained from the CMJ and the reactive strength index from the DJ decreased significantly over the season. The maintenance of isokinetic strength and the decrease in CMJ and DJ performance may indicate the presence of neuromuscular fatigue that accumulated over the course of the season.
Characterizations of nonsmooth robustly quasiconvex functions
- Bui, Hoa, Khanh, Pham, Tran, Thi
- Authors: Bui, Hoa , Khanh, Pham , Tran, Thi
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Optimization Theory and Applications Vol. 180, no. 3 (2019), p. 775-786
- Full Text:
- Reviewed:
- Description: Two criteria for the robust quasiconvexity of lower semicontinuous functions are established in terms of Fréchet subdifferentials in Asplund spaces. The first criterion extends to such spaces a result established by Barron et al. (Discrete Contin Dyn Syst Ser B 17:1693–1706, 2012). The second criterion is totally new even if it is applied to lower semicontinuous functions on finite-dimensional spaces. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
- Authors: Bui, Hoa , Khanh, Pham , Tran, Thi
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Optimization Theory and Applications Vol. 180, no. 3 (2019), p. 775-786
- Full Text:
- Reviewed:
- Description: Two criteria for the robust quasiconvexity of lower semicontinuous functions are established in terms of Fréchet subdifferentials in Asplund spaces. The first criterion extends to such spaces a result established by Barron et al. (Discrete Contin Dyn Syst Ser B 17:1693–1706, 2012). The second criterion is totally new even if it is applied to lower semicontinuous functions on finite-dimensional spaces. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
Choking interventions in sports : A systematic review
- Gröpel, Peter, Mesagno, Christopher
- Authors: Gröpel, Peter , Mesagno, Christopher
- Date: 2019
- Type: Text , Journal article , Review
- Relation: International Review of Sport and Exercise Psychology Vol. 12, no. 1 (2019), p. 176-201
- Full Text:
- Reviewed:
- Description: Choking under pressure describes suboptimal sport performance in stressful situations, which has led to two fundamental ‘choking’ models: distraction and self-focus. The purpose of this review was to provide an overview of empirical studies that have tested interventions used to alleviate choking. The systematic review includes 47 empirical studies published up to April 2017, including experimental, quasi-experimental, and single-case studies with athletes. These studies encompassed a variety of interventions (n = 13) that were either distraction based or self-focus based. In addition, a third group–acclimatisation interventions–was identified. The results indicate that, in general, choking interventions based on both choking models and on acclimatisation provide a benefit to performance under pressure. The most reported effective interventions were pre-performance routines, quiet eye training, left-hand contractions, and acclimatisation training. The use of dual task was beneficial for performance under pressure but harmful when used in training. Mixed evidence was found for analogy learning, and null effects were reported for goal setting, neurofeedback training, and reappraisal cues. These results may help athletes and coaches select and implement effective strategies and methods to improve performance under pressure.
- Authors: Gröpel, Peter , Mesagno, Christopher
- Date: 2019
- Type: Text , Journal article , Review
- Relation: International Review of Sport and Exercise Psychology Vol. 12, no. 1 (2019), p. 176-201
- Full Text:
- Reviewed:
- Description: Choking under pressure describes suboptimal sport performance in stressful situations, which has led to two fundamental ‘choking’ models: distraction and self-focus. The purpose of this review was to provide an overview of empirical studies that have tested interventions used to alleviate choking. The systematic review includes 47 empirical studies published up to April 2017, including experimental, quasi-experimental, and single-case studies with athletes. These studies encompassed a variety of interventions (n = 13) that were either distraction based or self-focus based. In addition, a third group–acclimatisation interventions–was identified. The results indicate that, in general, choking interventions based on both choking models and on acclimatisation provide a benefit to performance under pressure. The most reported effective interventions were pre-performance routines, quiet eye training, left-hand contractions, and acclimatisation training. The use of dual task was beneficial for performance under pressure but harmful when used in training. Mixed evidence was found for analogy learning, and null effects were reported for goal setting, neurofeedback training, and reappraisal cues. These results may help athletes and coaches select and implement effective strategies and methods to improve performance under pressure.
Colloidal carbon interference in the treatability of pulp and paper wastewater by MBR
- Scholes, Emily, Brook-Carter, Phillip, Verheyen, Vincent
- Authors: Scholes, Emily , Brook-Carter, Phillip , Verheyen, Vincent
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Environmental Chemical Engineering Vol. 7, no. 5 (2019), p. 1-9
- Full Text:
- Reviewed:
- Description: Pulp and paper wastewaters are challenging to treat due to their variability, complexity and toxicity. Membrane Bioreactor’s (MBR’s) provide high-quality filtrates but are subject to periods of low filterability / high capillary suction time (CST) which potentially limit their use in this application. There is a paucity of published literature concerning long-term operational issues in full-scale, industrial MBR’s. We hypothesised that either changes of bacterial population, alteration/reduction of bacterial metabolism or bacterial production of extra-cellular polymers (ESPs) increased CST and reduced filterability. This study, conducted over two years at the 16.4MLD Gippsland Water Factory, was structured to inform this bacterial centric hypothesis. However, no shifts in bacterial population were seen as causative of high CST and microbial stress levels and biological activity were observed to be low during high CST and no sign of toxicity was found. The strongest correlator with CST was the concentration of colloidal Total Organic Carbon of the mixed liquor suspended solids (MLSS) supernatant (following centrifugation). The carbonaceous colloids accumulated in the supernatant were named ‘Non-Centrifugable Total Organic Carbon’ (NCTOC). Their accumulation in the MLSS was found be due to their biologically refractory nature and their retention by the MBR membrane. The accumulation of NCTOC typically followed a period where the influent had a high colour and a high sodium to calcium ratio, which is consistent with a pulping by-product called ‘Black Liquor’. Additional experiments with Black Liquor allowed us to conclude that high CST can be produced by addition of Black Liquor.
- Authors: Scholes, Emily , Brook-Carter, Phillip , Verheyen, Vincent
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Environmental Chemical Engineering Vol. 7, no. 5 (2019), p. 1-9
- Full Text:
- Reviewed:
- Description: Pulp and paper wastewaters are challenging to treat due to their variability, complexity and toxicity. Membrane Bioreactor’s (MBR’s) provide high-quality filtrates but are subject to periods of low filterability / high capillary suction time (CST) which potentially limit their use in this application. There is a paucity of published literature concerning long-term operational issues in full-scale, industrial MBR’s. We hypothesised that either changes of bacterial population, alteration/reduction of bacterial metabolism or bacterial production of extra-cellular polymers (ESPs) increased CST and reduced filterability. This study, conducted over two years at the 16.4MLD Gippsland Water Factory, was structured to inform this bacterial centric hypothesis. However, no shifts in bacterial population were seen as causative of high CST and microbial stress levels and biological activity were observed to be low during high CST and no sign of toxicity was found. The strongest correlator with CST was the concentration of colloidal Total Organic Carbon of the mixed liquor suspended solids (MLSS) supernatant (following centrifugation). The carbonaceous colloids accumulated in the supernatant were named ‘Non-Centrifugable Total Organic Carbon’ (NCTOC). Their accumulation in the MLSS was found be due to their biologically refractory nature and their retention by the MBR membrane. The accumulation of NCTOC typically followed a period where the influent had a high colour and a high sodium to calcium ratio, which is consistent with a pulping by-product called ‘Black Liquor’. Additional experiments with Black Liquor allowed us to conclude that high CST can be produced by addition of Black Liquor.