Description:
Large scale integration of wind power can be deterred by congestion following an outage that results in constrained network capacity. Post outage congestion can be mitigated by the application of event control strategies; however they may not always benefit large wind farms. This paper investigates this problem in detail and proposes an advanced mathematical framework to model network congestion as functions of stochastic limits of network assets to capture post contingency risk of network congestion resulting through the constrained network capacity that limits high penetration of wind. The benefit of this approach is that it can limit the generation to be curtailed or re-dispatched by dynamically enhancing the network latent capacity in the event of outages or as per the need. The uniqueness of the proposed mathematical model is that it converts conventional thermal constraints to dynamic constraints by using a discretized stochastic penalty function with quadratic approximation of constraint relaxation penalty. The case study results with large and small network models suggest that the following an outage, wind utilization under dynamic line rating can be increased considerably if the wind power producers maintain around a 15% margin of operation.
Description:
Large scale integration of wind power can be deterred by congestion following an outage that results in constrained network capacity. Post outage congestion can be mitigated by the application of event control strategies; however they may not always benefit large wind farms. This paper investigates this problem in detail and proposes an advanced mathematical framework to model network congestion as functions of stochastic limits of network assets to capture post contingency risk of network congestion resulting through the constrained network capacity that limits high penetration of wind. The benefit of this approach is that it can limit the generation to be curtailed or re-dispatched by dynamically enhancing the network latent capacity in the event of outages or as per the need. The uniqueness of the proposed mathematical model is that it converts conventional thermal constraints to dynamic constraints by using a discretized stochastic penalty function with quadratic approximation of constraint relaxation penalty. The case study results with large and small network models suggest that the following an outage, wind utilization under dynamic line rating can be increased considerably if the wind power producers maintain around a 15% margin of operation.
Description:
Objectives: To describe the association between participants' person-related potential predictor variables and cumulative compliance with interventions for preventing ankle sprains: neuromuscular training, wearing an ankle brace, and a combined training and bracing. Design: Secondary analysis of compliance data from a randomized controlled trial (RCT) comparing measures preventing ankle ligament injuries. Methods: Ordinal regression with a backward selection method was used to obtain a descriptive statistical model linking participants' person-related potential predictor variables with the monthly cumulative compliance measurements for three interventions preventing ankle ligament injuries. Results: Having had a previous ankle injury was significantly associated with a higher compliance with all of the preventive measures trialed. Overall compliance with bracing and the combined intervention was significantly lower than the compliance with NM training. Per group analysis found that participating in a high-risk sport, like soccer, basketball, and volleyball, was significantly associated with a higher compliance with bracing, or a combined bracing and NM training. In contrast, participating in a high-risk sport was significantly associated with a lower per group compliance with NM training. Conclusions: Future studies should include at least registration of previous ankle sprains, sport participation (high- or low-risk), experience in NM training, and hours of sport exposure as possible predictors of compliance with interventions preventing ankle sprains. Practitioners should take into account these variables when prescribing preventive neuromuscular training or bracing. (C) 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Description:
Ant-based clustering (ABC) is a data clustering approach inspired from cemetery formation activities observed in real ant colonies. Building upon the premise of collective intelligence, such an approach uses multiple ant-like agents and a mixture of heuristics, in order to create systems that are capable of clustering real-world data. Many recently proposed ABC systems have shown competitive results, but these systems are geared towards adding new heuristics, resulting in increasingly complex systems that are harder to understand and improve. In contrast to this direction, we demonstrate that a state-of-the-art ABC system can be systematically evaluated and then simplified. The streamlined model, which we call SABC, differs fundamentally from traditional ABC systems as it does not use the ant-colony and several key components. Yet, our empirical study shows that SABC performs more effectively and effciently than the state-of-the-art ABC system.
Description:
Ant-based clustering (ABC) is a data clustering approach inspired from cemetery formation activities observed in real ant colonies. Building upon the premise of collective intelligence, such an approach uses multiple ant-like agents and a mixture of heuristics, in order to create systems that are capable of clustering real-world data. Many recently proposed ABC systems have shown competitive results, but these systems are geared towards adding new heuristics, resulting in increasingly complex systems that are harder to understand and improve. In contrast to this direction, we demonstrate that a state-of-the-art ABC system can be systematically evaluated and then simplified. The streamlined model, which we call SABC, differs fundamentally from traditional ABC systems as it does not use the ant-colony and several key components. Yet, our empirical study shows that SABC performs more effectively and effciently than the state-of-the-art ABC system.
Description:
Objectives: The objectives of the study were to assess the relationship between various player and game factors and risk of concussion; and to assess the reliability of video analysis for mechanistic assessment of concussion in Australian football. Methods: All impacts and collisions resulting in concussion were identified during the 2011 Australian Football League season. An extensive list of factors for assessment was created based upon previous analysis of concussion in Australian Football League and expert opinions. The authors independently reviewed the video clips and correlation for each factor was examined. Results: A total of 82 concussions were reported in 194 games (rate: 8.7 concussions per 1000 match hours; 95% confidence interval: 6.9-10.5). Player demographics and game variables such as venue, timing of the game (day, night or twilight), quarter, travel status (home or interstate) or score margin did not demonstrate a significant relationship with risk of concussion; although a higher percentage of concussions occurred in the first 5 min of game time of the quarter (36.6%), when compared to the last 5 min (20.7%). Variables with good inter-rater agreement included position on the ground, circumstances of the injury and cause of the impact. The remainder of the variables assessed had fair-poor inter-rater agreement. Common problems included insufficient or poor quality video and interpretation issues related to the definitions used. Conclusions: Clear definitions and good quality video from multiple camera angles are required to improve the utility of video analysis for concussion surveillance in Australian football. (C) 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Description:
In this paper we establish new rules for the calculus of the subdifferential mapping of the sum of two convex functions. Our results are established under conditions which are at an intermediate level of generality among those leading to the Hiriart-Urruty and Phelps formula (Hiriart-Urruty and Phelps, 1993 [15]), involving the approximate subdifferential, and the stronger assumption used in the well-known Moreau-Rockafellar formula (Rockafellar 1970, [23]; Moreau 1966, [20]), which only uses the exact subdifferential. We give an application to derive asymptotic optimality conditions for convex optimization.
Description:
In this paper we establish new rules for the calculus of the subdifferential mapping of the sum of two convex functions. Our results are established under conditions which are at an intermediate level of generality among those leading to the Hiriart-Urruty and Phelps formula (Hiriart-Urruty and Phelps, 1993 [15]), involving the approximate subdifferential, and the stronger assumption used in the well-known Moreau-Rockafellar formula (Rockafellar 1970, [23]; Moreau 1966, [20]), which only uses the exact subdifferential. We give an application to derive asymptotic optimality conditions for convex optimization. (C) 2016 Elsevier Inc. All rights reserved.
Description:
Background: Papers continue to be cited by authors even after they have been retracted. Retraction notices provide readers with information about retracted papers and may help minimise post-retraction citation. To date, a review of the quality of retraction notices in nursing science has not been reported. Design: An audit of retraction notices associated with 29 retracted manuscripts published in nursing science journals. Methods: Retraction notices were reviewed again using the Committee on Publication Ethics (COPE) guidelines. Results: In total, 28 retraction notices were retrieved and reviewed (one retracted paper did not have a retraction notice). Details of the retracted manuscripts were included in all reviewed notices and, in all but two, author names were reported. Details of the time between a paper being published and retracted were not reported and generally there was a little information in notices about how the retraction decisions were made. All retraction notices were freely available. Seven notices stated who had made the decision to retract. Twenty-two (77%) notices stated the reason for retraction. Notices were brief and contained factual information. The webpages of three retracted articles did not clearly indicate that the paper had been retracted. Conclusion: More detailed and informative retraction notices will inform readers and may help reduce post- retraction citation.
Description:
Objectives: Video analysis can provide critical information to improve diagnostic accuracy and speed of clinical decision-making in potential cases of concussion. The objective of this study was to validate a hierarchical flowchart for the assessment of video signs of concussion, and to determine whether its implementation could improve the process of game day video assessment. Methods: All impacts and collisions potentially resulting in a concussion were identified during 2012 and 2013 Australian Football League (AFL) seasons. Consensus definitions were developed for clinical signs associated with concussion. A hierarchical flowchart was developed based on the reliability and validity of the video signs of concussion. Ninety videos were assessed, with 45 incidents of clinically confirmed concussion, and 45 cases where no concussion was sustained. Each video was examined using the hierarchical flowchart, and a single response was given for each video based on the highest-ranking element in the flowchart. Results: No protective action, impact seizure, motor incoordination or blank/vacant look were the highest ranked video signs in almost half of the clinically confirmed concussions, but in only 8.8% of non-concussed individuals. The presence of facial injury, clutching at the head and slow to get up were the highest ranked sign in 77.7% of non-concussed individuals. Conclusions: This study suggests that the implementation of a flowchart model could improve timely assessment of concussion, and it identifies the video signs that should trigger automatic removal from play. (C) 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Description:
In order to inform strategies to increase levels of physical activity (PA) for a healthier society, it is important to understand participation trends in leisure-time physical activity (LTPA). Little is known about the context of LTPA participation, particularly from the perspective of "sport and recreation" (S&R) categories such as organised and club-based activities. The primary aim of this study is to contribute to the sport management literature by specifically examining PA participation levels and trends in Australia over a decade, for those aged 15 years and older, through the lens of S&R. This paper also discusses the potential synergy between the public health and sport management domains with regard to LTPA/S&R. The Australian Sports Commission provided data from the Exercise, Recreation and Sport Survey (ERASS), a population survey conducted quarterly from 2001 to 2010 by computer-assisted telephone interview. Participation in LTPA was analysed by year, gender and age, in three hierarchically related categories: (1) any LTPA participation, (2) participation in an organised context, and (3) organised participation in a club. Participation rates in any LTPA increased significantly over the decade. However, this was not matched by increases in organised and/or club participation, which largely remained steady over the 10-year period. Much of the organised participation was within a club setting, and participation in this context is more likely among males than females. There is some evidence that the overall level of LTPA is increasing, which is positive for health, but there was generally no increase in club-based participation, resulting in sport contributing relatively less to overall population LTPA. However, the depth of information available from population surveys regarding club-based LTPA is insufficient to draw definitive conclusions, or make important strategic decisions about sport and health policy. There is a critical need for more comprehensive sport participation data to provide the evidence for improved programme and policy development. An avenue for this to occur may be through the integration of participation data from peak sport organisations. (C) 2014 Sport Management Association of Australia and New Zealand. Published by Elsevier Ltd. All rights reserved.
Description:
In order to inform strategies to increase levels of physical activity (PA) for a healthier society, it is important to understand participation trends in leisure-time physical activity (LTPA). Little is known about the context of LTPA participation, particularly from the perspective of "sport and recreation" (S&R) categories such as organised and club-based activities. The primary aim of this study is to contribute to the sport management literature by specifically examining PA participation levels and trends in Australia over a decade, for those aged 15 years and older, through the lens of S&R. This paper also discusses the potential synergy between the public health and sport management domains with regard to LTPA/S&R. The Australian Sports Commission provided data from the Exercise, Recreation and Sport Survey (ERASS), a population survey conducted quarterly from 2001 to 2010 by computer-assisted telephone interview. Participation in LTPA was analysed by year, gender and age, in three hierarchically related categories: (1) any LTPA participation, (2) participation in an organised context, and (3) organised participation in a club. Participation rates in any LTPA increased significantly over the decade. However, this was not matched by increases in organised and/or club participation, which largely remained steady over the 10-year period. Much of the organised participation was within a club setting, and participation in this context is more likely among males than females. There is some evidence that the overall level of LTPA is increasing, which is positive for health, but there was generally no increase in club-based participation, resulting in sport contributing relatively less to overall population LTPA. However, the depth of information available from population surveys regarding club-based LTPA is insufficient to draw definitive conclusions, or make important strategic decisions about sport and health policy. There is a critical need for more comprehensive sport participation data to provide the evidence for improved programme and policy development. An avenue for this to occur may be through the integration of participation data from peak sport organisations. (C) 2014 Sport Management Association of Australia and New Zealand. Published by Elsevier Ltd. All rights reserved.
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.
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.
Description:
This paper focuses on modeling of multi-junction solar cell (MJSC) to improve the conversion efficiency using MATLAB/Simulink software. The multi-junction photovoltaic (PV) cell is investigated to obtain its maximum performance compare to the conventional silicon PV cell. MATLAB/Simulink modeled results show that tandem cell can provide almost 3-times maximum power compared to the conventional PV cells. Maximum power point tracker (MPPT) has also been performed to improve the conversion efficiency of the PV systems. The MPPT is able to assist the PV cells to attain more power efficiently and deliver electricity to the grid.