ADMM-based adaptive sampling strategy for nonholonomic mobile robotic sensor networks
- Le, Viet-Anh, Nguyen, Linh, Nghiem, Truong
- Authors: Le, Viet-Anh , Nguyen, Linh , Nghiem, Truong
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Sensors Journal Vol. 21, no. 13 (2021), p. 15369-15378
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- Description: This paper discusses the adaptive sampling problem in a nonholonomic mobile robotic sensor network for efficiently monitoring a spatial field. It is proposed to employ Gaussian process to model a spatial phenomenon and predict it at unmeasured positions, which enables the sampling optimization problem to be formulated by the use of the log determinant of a predicted covariance matrix at next sampling locations. The control, movement and nonholonomic dynamics constraints of the mobile sensors are also considered in the adaptive sampling optimization problem. In order to tackle the nonlinearity and nonconvexity of the objective function in the optimization problem we first exploit the linearized alternating direction method of multipliers (L-ADMM) method that can effectively simplify the objective function, though it is computationally expensive since a nonconvex problem needs to be solved exactly in each iteration. We then propose a novel approach called the successive convexified ADMM (SC-ADMM) that sequentially convexify the nonlinear dynamic constraints so that the original optimization problem can be split into convex subproblems. It is noted that both the L-ADMM algorithm and our SC-ADMM approach can solve the sampling optimization problem in either a centralized or a distributed manner. We validated the proposed approaches in 1000 experiments in a synthetic environment with a real-world dataset, where the obtained results suggest that both the L-ADMM and SC-ADMM techniques can provide good accuracy for the monitoring purpose. However, our proposed SC-ADMM approach computationally outperforms the L-ADMM counterpart, demonstrating its better practicality. © 2001-2012 IEEE.
- Authors: Le, Viet-Anh , Nguyen, Linh , Nghiem, Truong
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Sensors Journal Vol. 21, no. 13 (2021), p. 15369-15378
- Full Text:
- Reviewed:
- Description: This paper discusses the adaptive sampling problem in a nonholonomic mobile robotic sensor network for efficiently monitoring a spatial field. It is proposed to employ Gaussian process to model a spatial phenomenon and predict it at unmeasured positions, which enables the sampling optimization problem to be formulated by the use of the log determinant of a predicted covariance matrix at next sampling locations. The control, movement and nonholonomic dynamics constraints of the mobile sensors are also considered in the adaptive sampling optimization problem. In order to tackle the nonlinearity and nonconvexity of the objective function in the optimization problem we first exploit the linearized alternating direction method of multipliers (L-ADMM) method that can effectively simplify the objective function, though it is computationally expensive since a nonconvex problem needs to be solved exactly in each iteration. We then propose a novel approach called the successive convexified ADMM (SC-ADMM) that sequentially convexify the nonlinear dynamic constraints so that the original optimization problem can be split into convex subproblems. It is noted that both the L-ADMM algorithm and our SC-ADMM approach can solve the sampling optimization problem in either a centralized or a distributed manner. We validated the proposed approaches in 1000 experiments in a synthetic environment with a real-world dataset, where the obtained results suggest that both the L-ADMM and SC-ADMM techniques can provide good accuracy for the monitoring purpose. However, our proposed SC-ADMM approach computationally outperforms the L-ADMM counterpart, demonstrating its better practicality. © 2001-2012 IEEE.
Geometric design of the limaçon-to-circular fluid processing machine
- Phung, Truong, Sultan, Ibrahim
- Authors: Phung, Truong , Sultan, Ibrahim
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Mechanical Design, Transactions of the ASME Vol. 143, no. 10 (2021), p.
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- Description: A limaçon machine is a rotary positive displacement device, in which the housing and rotor are constructed of limaçon of Pascal curves. Previous works have been published to investigate the working of these machines in two applications: gas expanders and compressors. This article presents a theoretical investigation into the potential of modifying the rotor profile of the limaçon machines to simplify the machine's manufacturing process and to reduce production cost. The proposed modification will produce new characteristics for the housing-rotor interaction. An outcome that motivates the need to obtain new mathematical models to investigate the housing-rotor interference and describe the volumetric relationship of the new machine. This article also employs an optimization approach to design the best machine for a given set of operating conditions, i.e., expander, compressor, and pump. The outcome of this study confirms the validity of the proposed modification and its potential to produce a limaçon machine with favorable characteristics. Copyright © 2021 by ASME
- Authors: Phung, Truong , Sultan, Ibrahim
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Mechanical Design, Transactions of the ASME Vol. 143, no. 10 (2021), p.
- Full Text:
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- Description: A limaçon machine is a rotary positive displacement device, in which the housing and rotor are constructed of limaçon of Pascal curves. Previous works have been published to investigate the working of these machines in two applications: gas expanders and compressors. This article presents a theoretical investigation into the potential of modifying the rotor profile of the limaçon machines to simplify the machine's manufacturing process and to reduce production cost. The proposed modification will produce new characteristics for the housing-rotor interaction. An outcome that motivates the need to obtain new mathematical models to investigate the housing-rotor interference and describe the volumetric relationship of the new machine. This article also employs an optimization approach to design the best machine for a given set of operating conditions, i.e., expander, compressor, and pump. The outcome of this study confirms the validity of the proposed modification and its potential to produce a limaçon machine with favorable characteristics. Copyright © 2021 by ASME
Mobile robotic sensors for environmental monitoring using gaussian markov random field
- Nguyen, Linh, Kodagoda, Sarath, Ranasinghe, Ravindra, Dissanayake, Gamini
- Authors: Nguyen, Linh , Kodagoda, Sarath , Ranasinghe, Ravindra , Dissanayake, Gamini
- Date: 2021
- Type: Text , Journal article
- Relation: Robotica Vol. 39, no. 5 (2021), p. 862-884
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- Description: This paper addresses the issue of monitoring spatial environmental phenomena of interest utilizing information collected by a network of mobile, wireless, and noisy sensors that can take discrete measurements as they navigate through the environment. It is proposed to employ Gaussian Markov random field (GMRF) represented on an irregular discrete lattice by using the stochastic partial differential equations method to model the physical spatial field. It then derives a GMRF-based approach to effectively predict the field at unmeasured locations, given available observations, in both centralized and distributed manners. Furthermore, a novel but efficient optimality criterion is then proposed to design centralized and distributed adaptive sampling strategies for the mobile robotic sensors to find the most informative sampling paths in taking future measurements. By taking advantage of conditional independence property in the GMRF, the adaptive sampling optimization problem is proven to be resolved in a deterministic time. The effectiveness of the proposed approach is compared and demonstrated using pre-published data sets with appealing results. Copyright © The Author(s), 2020. Published by Cambridge University Press.
- Authors: Nguyen, Linh , Kodagoda, Sarath , Ranasinghe, Ravindra , Dissanayake, Gamini
- Date: 2021
- Type: Text , Journal article
- Relation: Robotica Vol. 39, no. 5 (2021), p. 862-884
- Full Text:
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- Description: This paper addresses the issue of monitoring spatial environmental phenomena of interest utilizing information collected by a network of mobile, wireless, and noisy sensors that can take discrete measurements as they navigate through the environment. It is proposed to employ Gaussian Markov random field (GMRF) represented on an irregular discrete lattice by using the stochastic partial differential equations method to model the physical spatial field. It then derives a GMRF-based approach to effectively predict the field at unmeasured locations, given available observations, in both centralized and distributed manners. Furthermore, a novel but efficient optimality criterion is then proposed to design centralized and distributed adaptive sampling strategies for the mobile robotic sensors to find the most informative sampling paths in taking future measurements. By taking advantage of conditional independence property in the GMRF, the adaptive sampling optimization problem is proven to be resolved in a deterministic time. The effectiveness of the proposed approach is compared and demonstrated using pre-published data sets with appealing results. Copyright © The Author(s), 2020. Published by Cambridge University Press.
Smart sensing-enabled decision support system for water scheduling in orange orchard
- Khan, Rahim, Zakarya, Muhammad, Balasubramanian, Venki, Jan, Mian, Menon, Varun
- Authors: Khan, Rahim , Zakarya, Muhammad , Balasubramanian, Venki , Jan, Mian , Menon, Varun
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Sensors Journal Vol. 21, no. 16 (2021), p. 17492-17499
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- Description: The scarcity of water resources throughout the world demands its optimum utilization in various sectors. Smart Sensing-enabled irrigation management systems are the ideal solutions to ensure the optimum utilization of water resources in the agriculture sector. This paper presents a wireless sensor network-enabled Decision Support System (DSS) for developing a need-based irrigation schedule for the orange orchard. For efficient monitoring of various in-field parameters, our proposed approach uses the latest smart sensing technology such as soil moisture, leaf-wetness, temperature and humidity. The proposed smart sensing-enabled test-bed was deployed in the orange orchard of our institute for approximately one year and successfully adjusted its irrigation schedule according to the needs and demands of the plants. Moreover, a modified Longest Common SubSequence (LCSS) mechanism is integrated with the proposed DSS for distinguishing multi-valued noise from the abrupt changing scenarios. To resolve the concurrent communication problem of two or more wasp-mote sensor boards with a common receiver, an enhanced RTS/CTS handshake mechanism is presented. Our proposed DSS compares the most recently refined data with pre-defined threshold values for efficient water management in the orchard. Irrigation activity is scheduled if water deficit criterion is met and the farmer is informed accordingly. Both the experimental and simulation results show that the proposed scheme performs better in comparison to the existing schemes. © 2001-2012 IEEE.
- Authors: Khan, Rahim , Zakarya, Muhammad , Balasubramanian, Venki , Jan, Mian , Menon, Varun
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Sensors Journal Vol. 21, no. 16 (2021), p. 17492-17499
- Full Text:
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- Description: The scarcity of water resources throughout the world demands its optimum utilization in various sectors. Smart Sensing-enabled irrigation management systems are the ideal solutions to ensure the optimum utilization of water resources in the agriculture sector. This paper presents a wireless sensor network-enabled Decision Support System (DSS) for developing a need-based irrigation schedule for the orange orchard. For efficient monitoring of various in-field parameters, our proposed approach uses the latest smart sensing technology such as soil moisture, leaf-wetness, temperature and humidity. The proposed smart sensing-enabled test-bed was deployed in the orange orchard of our institute for approximately one year and successfully adjusted its irrigation schedule according to the needs and demands of the plants. Moreover, a modified Longest Common SubSequence (LCSS) mechanism is integrated with the proposed DSS for distinguishing multi-valued noise from the abrupt changing scenarios. To resolve the concurrent communication problem of two or more wasp-mote sensor boards with a common receiver, an enhanced RTS/CTS handshake mechanism is presented. Our proposed DSS compares the most recently refined data with pre-defined threshold values for efficient water management in the orchard. Irrigation activity is scheduled if water deficit criterion is met and the farmer is informed accordingly. Both the experimental and simulation results show that the proposed scheme performs better in comparison to the existing schemes. © 2001-2012 IEEE.
An efficient 3-D model for remaining wall thicknesses of cast iron pipes in nondestructive testing
- Authors: Nguyen, Linh , Miro, Jaime
- Date: 2020
- Type: Text , Journal article
- Relation: IEEE Sensors Letters Vol. 4, no. 7 (2020), p.
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- Description: Over 50% of global pipes have been made of cast iron, and most of them are aging. In order to effectively estimate possibilities of their failures, which is paramount for efficiently managing asset infrastructures, it requires the remaining wall thickness (RWT) of a pipe to be known. In fact, RWT of the cast iron pipes can be primarily measured by the magnetism based nondestructive testing technologies though they are quite slow. To speed up the inspection process, it is proposed to sense RWT of a part of a pipe and then employ a model to predict RWT in the rest. Thus, this letter introduces a 3-D model to efficiently represent RWT of a pipe given measurements collected intermittently on the pipe's surface. The proposed model first transforms 3-D cylindrical coordinates to 3-D Cartesian coordinates before modeling RWT by Gaussian processes (GP). The transformation allows GP to work properly on RWT data gathered on a cylindrical pipe and effectively predict RWT at unmeasured locations. Moreover, periodicity of RWT along circumference of the pipe is naturally integrated. The effectiveness of the proposed approach is demonstrated by implementation in two real life inservice aging cast iron pipes, where the obtained results are highly promising. © 2017 IEEE.
- Authors: Nguyen, Linh , Miro, Jaime
- Date: 2020
- Type: Text , Journal article
- Relation: IEEE Sensors Letters Vol. 4, no. 7 (2020), p.
- Full Text:
- Reviewed:
- Description: Over 50% of global pipes have been made of cast iron, and most of them are aging. In order to effectively estimate possibilities of their failures, which is paramount for efficiently managing asset infrastructures, it requires the remaining wall thickness (RWT) of a pipe to be known. In fact, RWT of the cast iron pipes can be primarily measured by the magnetism based nondestructive testing technologies though they are quite slow. To speed up the inspection process, it is proposed to sense RWT of a part of a pipe and then employ a model to predict RWT in the rest. Thus, this letter introduces a 3-D model to efficiently represent RWT of a pipe given measurements collected intermittently on the pipe's surface. The proposed model first transforms 3-D cylindrical coordinates to 3-D Cartesian coordinates before modeling RWT by Gaussian processes (GP). The transformation allows GP to work properly on RWT data gathered on a cylindrical pipe and effectively predict RWT at unmeasured locations. Moreover, periodicity of RWT along circumference of the pipe is naturally integrated. The effectiveness of the proposed approach is demonstrated by implementation in two real life inservice aging cast iron pipes, where the obtained results are highly promising. © 2017 IEEE.
Automated health condition diagnosis of in situ wood utility poles using an intelligent non-destructive evaluation (NDE) framework
- Yu, Yang, Subhani, Mahbube, Hoshyar, Azadeh, Li, Jianchun, Li, Huan
- Authors: Yu, Yang , Subhani, Mahbube , Hoshyar, Azadeh , Li, Jianchun , Li, Huan
- Date: 2020
- Type: Text , Journal article
- Relation: International Journal of Structural Stability and Dynamics Vol. 20, no. 10 (2020), p.
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- Description: Wood utility poles are widely applied in power transmission and telecommunication systems in Australia. Because of a variety of external influence factors, such as fungi, termite and environmental conditions, failure of poles due to the wood degradation with time is of common occurrence with high degree uncertainty. The pole failure may result in serious consequences including both economic and public safety. Therefore, accurately and timely identifying the health condition of the utility poles is of great significance for economic and safe operation of electricity and communication networks. In this paper, a novel non-destructive evaluation (NDE) framework with advanced signal processing and artificial intelligence (AI) techniques is developed to diagnose the condition of utility pole in field. To begin with, the guided waves (GWs) generated within the pole is measured using multi-sensing technique, avoiding difficult interpretation of various wave modes which cannot be detected by only one sensor. Then, empirical mode decomposition (EMD) and principal component analysis (PCA) are employed to extract and select damage-sensitive features from the captured GW signals. Additionally, the up-to-date machine learning (ML) techniques are adopted to diagnose the health condition of the pole based on selected signal patterns. Eventually, the performance of the developed NDE framework is evaluated using the field testing data from 15 new and 24 decommissioned utility poles at the pole yard in Sydney. © 2020 World Scientific Publishing Company.
- Description: This research is supported by Australian Research Council via Linkage Project (LP110200162) and Industrial Transforming Research Hub for Nanoscience Based Construction Materials Manufacturing (IH150100006) as well as Ausgrid. The authors greatly appreciate the ¯nancial and technical supports from the funding bodies.
- Authors: Yu, Yang , Subhani, Mahbube , Hoshyar, Azadeh , Li, Jianchun , Li, Huan
- Date: 2020
- Type: Text , Journal article
- Relation: International Journal of Structural Stability and Dynamics Vol. 20, no. 10 (2020), p.
- Full Text:
- Reviewed:
- Description: Wood utility poles are widely applied in power transmission and telecommunication systems in Australia. Because of a variety of external influence factors, such as fungi, termite and environmental conditions, failure of poles due to the wood degradation with time is of common occurrence with high degree uncertainty. The pole failure may result in serious consequences including both economic and public safety. Therefore, accurately and timely identifying the health condition of the utility poles is of great significance for economic and safe operation of electricity and communication networks. In this paper, a novel non-destructive evaluation (NDE) framework with advanced signal processing and artificial intelligence (AI) techniques is developed to diagnose the condition of utility pole in field. To begin with, the guided waves (GWs) generated within the pole is measured using multi-sensing technique, avoiding difficult interpretation of various wave modes which cannot be detected by only one sensor. Then, empirical mode decomposition (EMD) and principal component analysis (PCA) are employed to extract and select damage-sensitive features from the captured GW signals. Additionally, the up-to-date machine learning (ML) techniques are adopted to diagnose the health condition of the pole based on selected signal patterns. Eventually, the performance of the developed NDE framework is evaluated using the field testing data from 15 new and 24 decommissioned utility poles at the pole yard in Sydney. © 2020 World Scientific Publishing Company.
- Description: This research is supported by Australian Research Council via Linkage Project (LP110200162) and Industrial Transforming Research Hub for Nanoscience Based Construction Materials Manufacturing (IH150100006) as well as Ausgrid. The authors greatly appreciate the ¯nancial and technical supports from the funding bodies.
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
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- 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
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- 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.
Modelling a biorefinery concept producing carbon fibre-polybutylene succinate composite foam
- Ghayur, Adeel, Verheyen, Vincent
- Authors: Ghayur, Adeel , Verheyen, Vincent
- Date: 2019
- Type: Text , Journal article
- Relation: Chemical Engineering Science Vol. 209, no. (2019), p. 1-7
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- Description: In this study, a novel biorefinery concept producing carbon fibre-poly(butylene succinate) composite foam (CPC foam) from lignocellulose and CO 2 is modelled. The biodegradable nature of poly(butylene succinate) would allow for easy carbon fibre recovery from the CPC foam for reuse at the end of product lifecycle, thus allowing for a circular materials flow. Technical simulation results show the biorefinery consumes 417 kg of biomass, 33 kg of CO 2 , 86 kg of methanol, 23 kg of acetic anhydride, 130 kWh of electricity and 1166 kW of heat per hour. The facility generates 72 kg of CPC foam, 82 kg of carbon fibre, 24 kg of tetrahydrofuran and 50 kg of dimethyl ether (DME). DME is used to fulfil parasitic electricity requirement. These results demonstrate the technical viability of this biorefinery although, research is needed to reduce parasitic energy demand. This carbon negative biorefinery avoids carcinogens and halogens for polymeric materials synthesis by utilising green chemistry principles and lignocellulose feedstock.
- Authors: Ghayur, Adeel , Verheyen, Vincent
- Date: 2019
- Type: Text , Journal article
- Relation: Chemical Engineering Science Vol. 209, no. (2019), p. 1-7
- Full Text:
- Reviewed:
- Description: In this study, a novel biorefinery concept producing carbon fibre-poly(butylene succinate) composite foam (CPC foam) from lignocellulose and CO 2 is modelled. The biodegradable nature of poly(butylene succinate) would allow for easy carbon fibre recovery from the CPC foam for reuse at the end of product lifecycle, thus allowing for a circular materials flow. Technical simulation results show the biorefinery consumes 417 kg of biomass, 33 kg of CO 2 , 86 kg of methanol, 23 kg of acetic anhydride, 130 kWh of electricity and 1166 kW of heat per hour. The facility generates 72 kg of CPC foam, 82 kg of carbon fibre, 24 kg of tetrahydrofuran and 50 kg of dimethyl ether (DME). DME is used to fulfil parasitic electricity requirement. These results demonstrate the technical viability of this biorefinery although, research is needed to reduce parasitic energy demand. This carbon negative biorefinery avoids carcinogens and halogens for polymeric materials synthesis by utilising green chemistry principles and lignocellulose feedstock.
The effects of sprint training and the Nordic hamstring exercise on eccentric hamstring strength and sprint performance in adolescent athletes
- Freeman, Brock, Young, Warren, Talpey, Scott, Smyth, Andrew, Pane, Calvin, Carlon, Todd
- Authors: Freeman, Brock , Young, Warren , Talpey, Scott , Smyth, Andrew , Pane, Calvin , Carlon, Todd
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Sports Medicine and Physical Fitness Vol. 59, no. 7 (2019), p. 1119-1125
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- Description: BACKGROUND. Hamstring strain injuries (HSI) are among the most common injuries in field-based team sports with a high-speed running component. The implementation of the Nordic hamstring exercise (NHE) is a well-documented method of improving eccentric hamstring strength to mitigate the risk of HSI occurrence. Sprint training is specific to the injury mechanism and is thought to activate the hamstrings through maximal eccentric contractions. The purpose of this study was to compare the effects of sprint training and the NHE on eccentric hamstring strength and sprint performance. METHODS. Twenty-eight participants (mean +/- SD age=16.21 +/- 1.34 years; height=1.75m +/- 0.10m; body mass=68.5kg +/- 12.1kg) completed an eccentric hamstring strength assessment and 40m sprint to assess acceleration and maximum speed. Participants were randomly allocated to either a NHE training or sprint training group. Two sessions per week for four-weeks of training was performed with baseline testing procedures repeated in the week following the intervention. Perceptions of soreness were recorded following the warm-up in each training session. RESULTS. Both the NHE (effect size=0.39, P<0.05) and sprint training (effect size=0.29, P<0.05) groups displayed significant gains in eccentric hamstring strength. The NHE group reported trivial improvements in sprint performance, whilst the sprint training group experienced a moderate improvement, specifically in maximum speed (ES=0.83 Moderate). Sprint training also produced greater perceptions of soreness than the NHE following a four-week training intervention, specifically before the start of the last session (P<0.05). CONCLUSIONS. These findings indicate that sprint training had a beneficial effect for both eccentric hamstring strength and sprint performance, whilst also producing greater soreness than the NHE following the final training session. It was concluded that a four-week block of maximum speed training may have both an injury prevention and performance enhancement benefit.
- Authors: Freeman, Brock , Young, Warren , Talpey, Scott , Smyth, Andrew , Pane, Calvin , Carlon, Todd
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Sports Medicine and Physical Fitness Vol. 59, no. 7 (2019), p. 1119-1125
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- Description: BACKGROUND. Hamstring strain injuries (HSI) are among the most common injuries in field-based team sports with a high-speed running component. The implementation of the Nordic hamstring exercise (NHE) is a well-documented method of improving eccentric hamstring strength to mitigate the risk of HSI occurrence. Sprint training is specific to the injury mechanism and is thought to activate the hamstrings through maximal eccentric contractions. The purpose of this study was to compare the effects of sprint training and the NHE on eccentric hamstring strength and sprint performance. METHODS. Twenty-eight participants (mean +/- SD age=16.21 +/- 1.34 years; height=1.75m +/- 0.10m; body mass=68.5kg +/- 12.1kg) completed an eccentric hamstring strength assessment and 40m sprint to assess acceleration and maximum speed. Participants were randomly allocated to either a NHE training or sprint training group. Two sessions per week for four-weeks of training was performed with baseline testing procedures repeated in the week following the intervention. Perceptions of soreness were recorded following the warm-up in each training session. RESULTS. Both the NHE (effect size=0.39, P<0.05) and sprint training (effect size=0.29, P<0.05) groups displayed significant gains in eccentric hamstring strength. The NHE group reported trivial improvements in sprint performance, whilst the sprint training group experienced a moderate improvement, specifically in maximum speed (ES=0.83 Moderate). Sprint training also produced greater perceptions of soreness than the NHE following a four-week training intervention, specifically before the start of the last session (P<0.05). CONCLUSIONS. These findings indicate that sprint training had a beneficial effect for both eccentric hamstring strength and sprint performance, whilst also producing greater soreness than the NHE following the final training session. It was concluded that a four-week block of maximum speed training may have both an injury prevention and performance enhancement benefit.
A 12-month prospective cohort study of symptoms of common mental disorders among professional rugby players
- Gouttebarge, Vincent, Hopley, Philip, Kerkhoffs, Gino, Verhagen, Evert, Viljoen, Wayne, Wylleman, Paul, Lambert, Mike
- Authors: Gouttebarge, Vincent , Hopley, Philip , Kerkhoffs, Gino , Verhagen, Evert , Viljoen, Wayne , Wylleman, Paul , Lambert, Mike
- Date: 2018
- Type: Text , Journal article
- Relation: European Journal of Sport Science Vol. 18, no. 7 (2018), p. 1004-1012
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- Description: The primary aims were to determine the 12-month incidence (and comorbidity) of symptoms of common mental disorders (CMD) among male professional rugby players and to explore their association with potential stressors. A secondary aim was to explore the view of male professional rugby players about the consequences of symptoms of CMD and related medical support/needs. An observational prospective cohort study with three measurements over a 12-month period was conducted among male professional rugby players from several countries. Symptoms of CMD (distress, anxiety/depression, sleep disturbance, eating disorders and adverse alcohol use) and stressors (adverse life events, rugby career dissatisfaction) were assessed through validated questionnaires. A total of 595 players (mean age of 26 years; mean career duration of 6 years) were enrolled, of which 333 completed the follow-up period. The incidence of symptoms of CMD were: 11% for distress, 28% for anxiety/depression, 12% for sleep disturbance, 11% for eating disorders and 22% for adverse alcohol use (13% for two simultaneous symptoms of CMD). Professional rugby players reporting recent adverse life events or career dissatisfaction were more likely to report symptoms of CMD but statistically significant associations were not found. Around 95% of the participants stated that symptoms of CMD can negatively influence rugby performances, while 46% mentioned that specific support measures for players were not available in professional rugby. Supportive and preventive measures directed towards symptoms of CMD should be developed to improve not only awareness and psychological resilience of rugby players but also their rugby performance and quality-of-life. © 2018, © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
- Authors: Gouttebarge, Vincent , Hopley, Philip , Kerkhoffs, Gino , Verhagen, Evert , Viljoen, Wayne , Wylleman, Paul , Lambert, Mike
- Date: 2018
- Type: Text , Journal article
- Relation: European Journal of Sport Science Vol. 18, no. 7 (2018), p. 1004-1012
- Full Text:
- Reviewed:
- Description: The primary aims were to determine the 12-month incidence (and comorbidity) of symptoms of common mental disorders (CMD) among male professional rugby players and to explore their association with potential stressors. A secondary aim was to explore the view of male professional rugby players about the consequences of symptoms of CMD and related medical support/needs. An observational prospective cohort study with three measurements over a 12-month period was conducted among male professional rugby players from several countries. Symptoms of CMD (distress, anxiety/depression, sleep disturbance, eating disorders and adverse alcohol use) and stressors (adverse life events, rugby career dissatisfaction) were assessed through validated questionnaires. A total of 595 players (mean age of 26 years; mean career duration of 6 years) were enrolled, of which 333 completed the follow-up period. The incidence of symptoms of CMD were: 11% for distress, 28% for anxiety/depression, 12% for sleep disturbance, 11% for eating disorders and 22% for adverse alcohol use (13% for two simultaneous symptoms of CMD). Professional rugby players reporting recent adverse life events or career dissatisfaction were more likely to report symptoms of CMD but statistically significant associations were not found. Around 95% of the participants stated that symptoms of CMD can negatively influence rugby performances, while 46% mentioned that specific support measures for players were not available in professional rugby. Supportive and preventive measures directed towards symptoms of CMD should be developed to improve not only awareness and psychological resilience of rugby players but also their rugby performance and quality-of-life. © 2018, © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Injuries in field hockey players : A systematic review
- Barboza, Saulo, Joseph, Corey, Nauta, Joske, van Mechelen, Willem, Verhagen, Evert
- Authors: Barboza, Saulo , Joseph, Corey , Nauta, Joske , van Mechelen, Willem , Verhagen, Evert
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 48, no. 4 (2018), p. 849-866
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- Description: Background: To commence injury prevention efforts, it is necessary to understand the magnitude of the injury problem. No systematic reviews have yet investigated the extent of injuries in field hockey, despite the popularity of the sport worldwide. Objective: Our objective was to describe the rate and severity of injuries in field hockey and investigate their characteristics. Methods: We conducted electronic searches in PubMed, Embase, SPORTDiscus, and CINAHL. Prospective cohort studies were included if they were published in English in a peer-reviewed journal and observed all possible injuries sustained by field hockey players during the period of the study. Results: The risk of bias score of the 22 studies included ranged from three to nine of a possible ten. In total, 12 studies (55%) reported injuries normalized by field hockey exposure. Injury rates ranged from 0.1 injuries (in school-aged players) to 90.9 injuries (in Africa Cup of Nations) per 1000 player-hours and from one injury (in high-school women) to 70 injuries (in under-21 age women) per 1000 player-sessions. Studies used different classifications for injury severity, but—within studies—injuries were included mostly in the less severe category. The lower limbs were most affected, and contusions/hematomas and abrasions were common types of injury. Contact injuries are common, but non-contact injuries are also a cause for concern. Conclusions: Considerable heterogeneity meant it was not possible to draw conclusive findings on the extent of the rate and severity of injuries. Establishing the extent of sports injury is considered the first step towards prevention, so there is a need for a consensus on injury surveillance in field hockey. © 2018, The Author(s).
- Authors: Barboza, Saulo , Joseph, Corey , Nauta, Joske , van Mechelen, Willem , Verhagen, Evert
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 48, no. 4 (2018), p. 849-866
- Full Text:
- Reviewed:
- Description: Background: To commence injury prevention efforts, it is necessary to understand the magnitude of the injury problem. No systematic reviews have yet investigated the extent of injuries in field hockey, despite the popularity of the sport worldwide. Objective: Our objective was to describe the rate and severity of injuries in field hockey and investigate their characteristics. Methods: We conducted electronic searches in PubMed, Embase, SPORTDiscus, and CINAHL. Prospective cohort studies were included if they were published in English in a peer-reviewed journal and observed all possible injuries sustained by field hockey players during the period of the study. Results: The risk of bias score of the 22 studies included ranged from three to nine of a possible ten. In total, 12 studies (55%) reported injuries normalized by field hockey exposure. Injury rates ranged from 0.1 injuries (in school-aged players) to 90.9 injuries (in Africa Cup of Nations) per 1000 player-hours and from one injury (in high-school women) to 70 injuries (in under-21 age women) per 1000 player-sessions. Studies used different classifications for injury severity, but—within studies—injuries were included mostly in the less severe category. The lower limbs were most affected, and contusions/hematomas and abrasions were common types of injury. Contact injuries are common, but non-contact injuries are also a cause for concern. Conclusions: Considerable heterogeneity meant it was not possible to draw conclusive findings on the extent of the rate and severity of injuries. Establishing the extent of sports injury is considered the first step towards prevention, so there is a need for a consensus on injury surveillance in field hockey. © 2018, The Author(s).
A prospective cohort study on symptoms of common mental disorders among Dutch elite athletes
- Gouttebarge, Vincent, Jonkers, Ruud, Moen, Maarten, Verhagen, Evert, Wylleman, Paul, Kerkhoffs, Gino
- Authors: Gouttebarge, Vincent , Jonkers, Ruud , Moen, Maarten , Verhagen, Evert , Wylleman, Paul , Kerkhoffs, Gino
- Date: 2017
- Type: Text , Journal article
- Relation: Physician and Sportsmedicine Vol. 45, no. 4 (2017), p. 426-432
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- Description: Objective: Scientific knowledge about symptoms of common mental disorders in elite sports is scarce. Consequently, the objectives of the study were to (i) establish the 12-month incidence of symptoms of common mental disorders (CMD; distress, anxiety/depression, sleep disturbance, adverse alcohol use, eating disorders) among Dutch elite athletes and (ii) explore their potential association with several stressors (being injured, recent life events, career dissatisfaction).Methods: A prospective cohort study with a 12-month follow-up period was conducted. The study used validated questionnaires to assess symptoms of common mental disorders (thus not clinically diagnosed) as well as several stressors; an electronic questionnaire was set up and repeatedly distributed.Results: A total of 203 elite athletes gave their written informed consent to participate in the study, from which 143 completed the 12-month follow-up period (follow-up rate of 70%). Incidence of symptoms of CMD ranged from 6% for adverse alcohol use to 57% for symptoms of anxiety/depression. Over the follow-up period, around 17% of the participants reported two simultaneous symptoms of CMD, and around 19% reported three simultaneous symptoms of CMD. Inferences between some stressors and symptoms of CMD were found but none of the associations were statistically significant.Conclusions: Substantial 12-month incidence rates of symptoms of CMD (self-reported and not clinically diagnosed) were found among Dutch elite athletes (especially for anxiety/depression), appearing similar to the ones found among athletes from other sports disciplines and the Dutch general population. Also, inferences between some stressors and symptoms of CMD were found but none of the associations were statistically significant. Supportive and preventive measures directed towards symptoms of CMD should be developed to improve awareness and psychological resilience of athletes, which would likely improve their performance and quality-of-life.
- Authors: Gouttebarge, Vincent , Jonkers, Ruud , Moen, Maarten , Verhagen, Evert , Wylleman, Paul , Kerkhoffs, Gino
- Date: 2017
- Type: Text , Journal article
- Relation: Physician and Sportsmedicine Vol. 45, no. 4 (2017), p. 426-432
- Full Text:
- Reviewed:
- Description: Objective: Scientific knowledge about symptoms of common mental disorders in elite sports is scarce. Consequently, the objectives of the study were to (i) establish the 12-month incidence of symptoms of common mental disorders (CMD; distress, anxiety/depression, sleep disturbance, adverse alcohol use, eating disorders) among Dutch elite athletes and (ii) explore their potential association with several stressors (being injured, recent life events, career dissatisfaction).Methods: A prospective cohort study with a 12-month follow-up period was conducted. The study used validated questionnaires to assess symptoms of common mental disorders (thus not clinically diagnosed) as well as several stressors; an electronic questionnaire was set up and repeatedly distributed.Results: A total of 203 elite athletes gave their written informed consent to participate in the study, from which 143 completed the 12-month follow-up period (follow-up rate of 70%). Incidence of symptoms of CMD ranged from 6% for adverse alcohol use to 57% for symptoms of anxiety/depression. Over the follow-up period, around 17% of the participants reported two simultaneous symptoms of CMD, and around 19% reported three simultaneous symptoms of CMD. Inferences between some stressors and symptoms of CMD were found but none of the associations were statistically significant.Conclusions: Substantial 12-month incidence rates of symptoms of CMD (self-reported and not clinically diagnosed) were found among Dutch elite athletes (especially for anxiety/depression), appearing similar to the ones found among athletes from other sports disciplines and the Dutch general population. Also, inferences between some stressors and symptoms of CMD were found but none of the associations were statistically significant. Supportive and preventive measures directed towards symptoms of CMD should be developed to improve awareness and psychological resilience of athletes, which would likely improve their performance and quality-of-life.
A scaled boundary finite element formulation with bubble functions for elasto-static analyses of functionally graded materials
- Ooi, Ean Tat, Song, Chongmin, Natarajan, Sundararajan
- Authors: Ooi, Ean Tat , Song, Chongmin , Natarajan, Sundararajan
- Date: 2017
- Type: Text , Journal article
- Relation: Computational Mechanics Vol. 60, no. 6 (2017), p. 943-967
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- Description: This manuscript presents an extension of the recently-developed high order complete scaled boundary shape functions to model elasto-static problems in functionally graded materials. Both isotropic and orthotropic functionally graded materials are modelled. The high order complete properties of the shape functions are realized through the introduction of bubble-like functions derived from the equilibrium condition of a polygon subjected to body loads. The bubble functions preserve the displacement compatibility between the elements in the mesh. The heterogeneity resulting from the material gradient introduces additional terms in the polygon stiffness matrix that are integrated analytically. Few numerical benchmarks were used to validate the developed formulation. The high order completeness property of the bubble functions result in superior accuracy and convergence rates for generic elasto-static and fracture problems involving functionally graded materials. © 2017, Springer-Verlag GmbH Germany.
- Authors: Ooi, Ean Tat , Song, Chongmin , Natarajan, Sundararajan
- Date: 2017
- Type: Text , Journal article
- Relation: Computational Mechanics Vol. 60, no. 6 (2017), p. 943-967
- Full Text:
- Reviewed:
- Description: This manuscript presents an extension of the recently-developed high order complete scaled boundary shape functions to model elasto-static problems in functionally graded materials. Both isotropic and orthotropic functionally graded materials are modelled. The high order complete properties of the shape functions are realized through the introduction of bubble-like functions derived from the equilibrium condition of a polygon subjected to body loads. The bubble functions preserve the displacement compatibility between the elements in the mesh. The heterogeneity resulting from the material gradient introduces additional terms in the polygon stiffness matrix that are integrated analytically. Few numerical benchmarks were used to validate the developed formulation. The high order completeness property of the bubble functions result in superior accuracy and convergence rates for generic elasto-static and fracture problems involving functionally graded materials. © 2017, Springer-Verlag GmbH Germany.
Health and economic burden of running-related injuries in Dutch trailrunners : A prospective cohort study
- Hespanhol Junior, Luiz, van Mechelen, Willem, Verhagen, Evert
- Authors: Hespanhol Junior, Luiz , van Mechelen, Willem , Verhagen, Evert
- Date: 2017
- Type: Text , Journal article
- Relation: Sports Medicine Vol. 47, no. 2 (2017), p. 367-377
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- Description: Background: Trailrunning is becoming very popular. However, the risk and burden of running-related injuries (RRI) in trailrunning is not well established. Objective: To investigate the prevalence, injury rate, severity, nature, and economic burden of RRIs in Dutch trailrunners. Methods: This prospective cohort study included 228 trailrunners aged 18 years or over (range 23–67), and was conducted between October 2013 and December 2014. After completing the baseline questionnaire, the Oslo Sports Trauma Research Center Questionnaire on Health Problems was administered every 2 weeks to collect data on RRIs. Participants who reported RRIs were asked about healthcare utilization (direct costs) and absenteeism from paid work (indirect costs). RRI was defined as disorders of the musculoskeletal system or concussions experienced or sustained during participation in running. Results: The mean prevalence of RRIs measured over time was 22.4 % [95 % confidence interval (CI) 20.9–24.0], and the injury rate was 10.7 RRIs per 1000 h of running (95 % CI 9.4–12.1). The prevalence was higher for overuse (17.7 %; 95 % CI 15.9–19.5) than for acute (4.1 %; 95 % CI 3.3–5.0) RRIs. Also, the injury rate was higher for overuse (8.1; 95 % CI 6.9–9.3) than for acute (2.7; 95 % CI 2.0–3.4) RRIs. The median of the severity score was 35.0 [25–75 %, interquartile range (IQR) 22.0–55.7], and the median of the duration of RRIs was 2.0 weeks (IQR 2.0–6.0) during the study. The total economic burden of RRIs was estimated at €172.22 (95 % CI 117.10–271.74) per RRI, and €1849.49 (95 % CI 1180.62–3058.91) per 1000 h of running. An RRI was estimated to have a direct cost of €60.92 (95 % CI 45.11–94.90) and an indirect cost of €111.30 (95 % CI 61.02–192.75). Conclusions: The health and economic burden of RRIs presented in this study are significant for trailrunners and for society. Therefore, efforts should be made in order to prevent RRIs in trailrunners. © 2016, The Author(s).
- Authors: Hespanhol Junior, Luiz , van Mechelen, Willem , Verhagen, Evert
- Date: 2017
- Type: Text , Journal article
- Relation: Sports Medicine Vol. 47, no. 2 (2017), p. 367-377
- Full Text:
- Reviewed:
- Description: Background: Trailrunning is becoming very popular. However, the risk and burden of running-related injuries (RRI) in trailrunning is not well established. Objective: To investigate the prevalence, injury rate, severity, nature, and economic burden of RRIs in Dutch trailrunners. Methods: This prospective cohort study included 228 trailrunners aged 18 years or over (range 23–67), and was conducted between October 2013 and December 2014. After completing the baseline questionnaire, the Oslo Sports Trauma Research Center Questionnaire on Health Problems was administered every 2 weeks to collect data on RRIs. Participants who reported RRIs were asked about healthcare utilization (direct costs) and absenteeism from paid work (indirect costs). RRI was defined as disorders of the musculoskeletal system or concussions experienced or sustained during participation in running. Results: The mean prevalence of RRIs measured over time was 22.4 % [95 % confidence interval (CI) 20.9–24.0], and the injury rate was 10.7 RRIs per 1000 h of running (95 % CI 9.4–12.1). The prevalence was higher for overuse (17.7 %; 95 % CI 15.9–19.5) than for acute (4.1 %; 95 % CI 3.3–5.0) RRIs. Also, the injury rate was higher for overuse (8.1; 95 % CI 6.9–9.3) than for acute (2.7; 95 % CI 2.0–3.4) RRIs. The median of the severity score was 35.0 [25–75 %, interquartile range (IQR) 22.0–55.7], and the median of the duration of RRIs was 2.0 weeks (IQR 2.0–6.0) during the study. The total economic burden of RRIs was estimated at €172.22 (95 % CI 117.10–271.74) per RRI, and €1849.49 (95 % CI 1180.62–3058.91) per 1000 h of running. An RRI was estimated to have a direct cost of €60.92 (95 % CI 45.11–94.90) and an indirect cost of €111.30 (95 % CI 61.02–192.75). Conclusions: The health and economic burden of RRIs presented in this study are significant for trailrunners and for society. Therefore, efforts should be made in order to prevent RRIs in trailrunners. © 2016, The Author(s).
Incidence, aetiology and prevention of musculoskeletal injuries in volleyball : A systematic review of the literature
- Kilic, O., Maas, Mario, Verhagen, Evert, Zwerver, Johannes, Gouttebarge, Vincent
- Authors: Kilic, O. , Maas, Mario , Verhagen, Evert , Zwerver, Johannes , Gouttebarge, Vincent
- Date: 2017
- Type: Text , Journal article , Review
- Relation: European Journal of Sport Science Vol. 17, no. 6 (2017), p. 765-793
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- Description: Currently, there is no overview of the incidence and (volleyball-specific) risk factors of musculoskeletal injuries among volleyball players, nor any insight into the effect of preventive measures on the incidence of injuries in volleyball. This study aimed to review systematically the scientific evidence on the incidence, prevalence, aetiology and preventive measures of volleyball injuries. To this end, a highly sensitive search strategy was built based on two groups of keywords (and their synonyms). Two electronic databases were searched, namely Medline (biomedical literature) via Pubmed, and SPORTDiscus (sports and sports medicine literature) via EBSCOhost. The results showed that ankle, knee and shoulder injuries are the most common injuries sustained while playing volleyball. Results are presented separately for acute and overuse injuries, as well as for contact and non-contact injuries. Measures to prevent musculoskeletal injuries, anterior knee injuries and ankle injuries were identified in the scientific literature. These preventive measures were found to have a significant effect on decreasing the occurrence of volleyball injuries (for instance on ankle injuries with a reduction from 0.9 to 0.5 injuries per 1000 player hours). Our systematic review showed that musculoskeletal injuries are common among volleyball players, while effective preventive measures remain scarce. Further epidemiological studies should focus on other specific injuries besides knee and ankle injuries, and should also report their prevalence and not only the incidence. Additionally, high-quality studies on the aetiology and prevention of shoulder injuries are lacking and should be a focus of future studies. © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
- Authors: Kilic, O. , Maas, Mario , Verhagen, Evert , Zwerver, Johannes , Gouttebarge, Vincent
- Date: 2017
- Type: Text , Journal article , Review
- Relation: European Journal of Sport Science Vol. 17, no. 6 (2017), p. 765-793
- Full Text:
- Reviewed:
- Description: Currently, there is no overview of the incidence and (volleyball-specific) risk factors of musculoskeletal injuries among volleyball players, nor any insight into the effect of preventive measures on the incidence of injuries in volleyball. This study aimed to review systematically the scientific evidence on the incidence, prevalence, aetiology and preventive measures of volleyball injuries. To this end, a highly sensitive search strategy was built based on two groups of keywords (and their synonyms). Two electronic databases were searched, namely Medline (biomedical literature) via Pubmed, and SPORTDiscus (sports and sports medicine literature) via EBSCOhost. The results showed that ankle, knee and shoulder injuries are the most common injuries sustained while playing volleyball. Results are presented separately for acute and overuse injuries, as well as for contact and non-contact injuries. Measures to prevent musculoskeletal injuries, anterior knee injuries and ankle injuries were identified in the scientific literature. These preventive measures were found to have a significant effect on decreasing the occurrence of volleyball injuries (for instance on ankle injuries with a reduction from 0.9 to 0.5 injuries per 1000 player hours). Our systematic review showed that musculoskeletal injuries are common among volleyball players, while effective preventive measures remain scarce. Further epidemiological studies should focus on other specific injuries besides knee and ankle injuries, and should also report their prevalence and not only the incidence. Additionally, high-quality studies on the aetiology and prevention of shoulder injuries are lacking and should be a focus of future studies. © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Intervention strategies used in sport injury prevention studies : A systematic review identifying studies applying the Haddon matrix
- Vriend, Ingrid, Gouttebarge, Vincent, Finch, Caroline, van Mechelen, Willem, Verhagen, Evert
- Authors: Vriend, Ingrid , Gouttebarge, Vincent , Finch, Caroline , van Mechelen, Willem , Verhagen, Evert
- Date: 2017
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 47, no. 10 (2017), p. 2027-2043
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- Reviewed:
- Description: Background: Prevention of sport injuries is crucial to maximise the health and societal benefits of a physically active lifestyle. To strengthen the translation and implementation of the available evidence base on effective preventive measures, a range of potentially relevant strategies should be considered. Objective: Our aim was to identify and categorise intervention strategies for the prevention of acute sport injuries evaluated in the scientific literature, applying the Haddon matrix, and identify potential knowledge gaps. Methods: Five electronic databases were searched (PubMed, EMBASE, SPORTDiscus, CINAHL, Cochrane) for studies that evaluated the effect of interventions on the occurrence of acute sport injuries. Studies were required to include a control group/condition, prospective data collection, and a quantitative injury outcome measure. Results: A total of 155 studies were included, mostly randomised controlled trials (43%). The majority of studies (55%) focussed on strategies requiring a behavioural change on the part of athletes. Studies predominantly evaluated the preventive effect of various training programmes targeted at the ‘pre-event’ phase (n = 73) and the use of equipment to avoid injury in the ‘event phase’ (n = 29). A limited number of studies evaluated the preventive effect of strategies geared at rules and regulations (n = 14), and contextual modifications (n = 18). Studies specifically aimed at preventing re-injuries were a minority (n = 8), and were mostly related to ankle sprains (n = 5). Conclusions: Valuable insight into the extent of the evidence base of sport injury prevention studies was obtained for 20 potential intervention strategies. This approach can be used to monitor potential gaps in the knowledge base on sport injury prevention. © 2017, The Author(s).
- Authors: Vriend, Ingrid , Gouttebarge, Vincent , Finch, Caroline , van Mechelen, Willem , Verhagen, Evert
- Date: 2017
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 47, no. 10 (2017), p. 2027-2043
- Full Text:
- Reviewed:
- Description: Background: Prevention of sport injuries is crucial to maximise the health and societal benefits of a physically active lifestyle. To strengthen the translation and implementation of the available evidence base on effective preventive measures, a range of potentially relevant strategies should be considered. Objective: Our aim was to identify and categorise intervention strategies for the prevention of acute sport injuries evaluated in the scientific literature, applying the Haddon matrix, and identify potential knowledge gaps. Methods: Five electronic databases were searched (PubMed, EMBASE, SPORTDiscus, CINAHL, Cochrane) for studies that evaluated the effect of interventions on the occurrence of acute sport injuries. Studies were required to include a control group/condition, prospective data collection, and a quantitative injury outcome measure. Results: A total of 155 studies were included, mostly randomised controlled trials (43%). The majority of studies (55%) focussed on strategies requiring a behavioural change on the part of athletes. Studies predominantly evaluated the preventive effect of various training programmes targeted at the ‘pre-event’ phase (n = 73) and the use of equipment to avoid injury in the ‘event phase’ (n = 29). A limited number of studies evaluated the preventive effect of strategies geared at rules and regulations (n = 14), and contextual modifications (n = 18). Studies specifically aimed at preventing re-injuries were a minority (n = 8), and were mostly related to ankle sprains (n = 5). Conclusions: Valuable insight into the extent of the evidence base of sport injury prevention studies was obtained for 20 potential intervention strategies. This approach can be used to monitor potential gaps in the knowledge base on sport injury prevention. © 2017, The Author(s).
A review of instrumented equipment to investigate head impacts in sport
- Authors: Patton, Declan
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Applied Bionics and Biomechanics Vol. 2016, no. (2016), p. 1-17
- Full Text:
- Reviewed:
- Description: Contact, collision, and combat sports have more head impacts as compared to noncontact sports; therefore, such sports are uniquely suited to the investigation of head impact biomechanics. Recent advances in technology have enabled the development of instrumented equipment, which can estimate the head impact kinematics of human subjects in vivo. Literature pertaining to head impact measurement devices was reviewed and usage, in terms of validation and field studies, of such devices was discussed. Over the past decade, instrumented equipment has recorded millions of impacts in the laboratory, on the field, in the ring, and on the ice. Instrumented equipment is not without limitations; however, in vivo head impact data is crucial to investigate head injury mechanisms and further the understanding of concussion. © 2016 Declan A. Patton.
- Authors: Patton, Declan
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Applied Bionics and Biomechanics Vol. 2016, no. (2016), p. 1-17
- Full Text:
- Reviewed:
- Description: Contact, collision, and combat sports have more head impacts as compared to noncontact sports; therefore, such sports are uniquely suited to the investigation of head impact biomechanics. Recent advances in technology have enabled the development of instrumented equipment, which can estimate the head impact kinematics of human subjects in vivo. Literature pertaining to head impact measurement devices was reviewed and usage, in terms of validation and field studies, of such devices was discussed. Over the past decade, instrumented equipment has recorded millions of impacts in the laboratory, on the field, in the ring, and on the ice. Instrumented equipment is not without limitations; however, in vivo head impact data is crucial to investigate head injury mechanisms and further the understanding of concussion. © 2016 Declan A. Patton.
Compliance with sport injury prevention interventions in randomised controlled trials : A systematic review
- van Reijen, Miriam, Vriend, Ingrid, van Mechelen, Willem, Finch, Caroline, Verhagen, Evert
- Authors: van Reijen, Miriam , Vriend, Ingrid , van Mechelen, Willem , Finch, Caroline , Verhagen, Evert
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 46, no. 8 (2016), p. 1125-1139
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- Description: Introduction Sport injury prevention studies vary in the way compliance with an intervention is defined, measured and adjusted for. Objective The objective of this systematic review was to assess the extent to which sport injury prevention randomised controlled trials (RCTs) have defined, measured and adjusted results for compliance with an injury prevention intervention. Methods An electronic search was performed in MEDLINE, PubMed, the Cochrane Center of Controlled Trials, CINAHL (Cumulative Index to Nursing and Allied Health Literature), PEDro (Physiotherapy Evidence Database) and SPORTDiscus. English RCTs, quasi-RCTs and cluster-RCTs were considered eligible. Trials that involved physically active individuals or examined the effects of an intervention aimed at the prevention of sport-or physical activity-related injuries were included. Results Of the total of 100 studies included, 71.6 % mentioned compliance or a related term, 68.8 % provided details on compliance measurement and 51.4 % provided compliance data. Only 19.3 % analysed the effect of compliance rates on study outcomes. While studies used heterogeneous methods, pooled effects could not be presented. Conclusions Studies that account for compliance demonstrated that compliance significant affects study outcomes. The way compliance is dealt with in preventions studies is subject to a large degree of heterogeneity. Valid and reliable tools to measure and report compliance are needed and should be matched to a uniform definition of compliance.
- Authors: van Reijen, Miriam , Vriend, Ingrid , van Mechelen, Willem , Finch, Caroline , Verhagen, Evert
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 46, no. 8 (2016), p. 1125-1139
- Full Text:
- Reviewed:
- Description: Introduction Sport injury prevention studies vary in the way compliance with an intervention is defined, measured and adjusted for. Objective The objective of this systematic review was to assess the extent to which sport injury prevention randomised controlled trials (RCTs) have defined, measured and adjusted results for compliance with an injury prevention intervention. Methods An electronic search was performed in MEDLINE, PubMed, the Cochrane Center of Controlled Trials, CINAHL (Cumulative Index to Nursing and Allied Health Literature), PEDro (Physiotherapy Evidence Database) and SPORTDiscus. English RCTs, quasi-RCTs and cluster-RCTs were considered eligible. Trials that involved physically active individuals or examined the effects of an intervention aimed at the prevention of sport-or physical activity-related injuries were included. Results Of the total of 100 studies included, 71.6 % mentioned compliance or a related term, 68.8 % provided details on compliance measurement and 51.4 % provided compliance data. Only 19.3 % analysed the effect of compliance rates on study outcomes. While studies used heterogeneous methods, pooled effects could not be presented. Conclusions Studies that account for compliance demonstrated that compliance significant affects study outcomes. The way compliance is dealt with in preventions studies is subject to a large degree of heterogeneity. Valid and reliable tools to measure and report compliance are needed and should be matched to a uniform definition of compliance.
Global optimal trajectory in Chaos and NP-Hardness
- Latorre, Vittorio, Gao, David
- Authors: Latorre, Vittorio , Gao, David
- Date: 2016
- Type: Text , Journal article
- Relation: International Journal of Bifurcation and Chaos Vol. 26, no. 8 (2016), p. 1-14
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- Reviewed:
- Description: This paper presents an unconventional theory and method for solving general nonlinear dynamical systems. Instead of the direct iterative methods, the discretized nonlinear system is first formulated as a global optimization problem via the least squares method. A newly developed canonical duality theory shows that this nonconvex minimization problem can be solved deterministically in polynomial time if a global optimality condition is satisfied. The so-called pseudo-chaos produced by linear iterative methods are mainly due to the intrinsic numerical error accumulations. Otherwise, the global optimization problem could be NP-hard and the nonlinear system can be really chaotic. A conjecture is proposed, which reveals the connection between chaos in nonlinear dynamics and NP-hardness in computer science. The methodology and the conjecture are verified by applications to the well-known logistic equation, a forced memristive circuit and the Lorenz system. Computational results show that the canonical duality theory can be used to identify chaotic systems and to obtain realistic global optimal solutions in nonlinear dynamical systems. The method and results presented in this paper should bring some new insights into nonlinear dynamical systems and NP-hardness in computational complexity theory. © 2016 World Scientific Publishing Company.
- Authors: Latorre, Vittorio , Gao, David
- Date: 2016
- Type: Text , Journal article
- Relation: International Journal of Bifurcation and Chaos Vol. 26, no. 8 (2016), p. 1-14
- Full Text:
- Reviewed:
- Description: This paper presents an unconventional theory and method for solving general nonlinear dynamical systems. Instead of the direct iterative methods, the discretized nonlinear system is first formulated as a global optimization problem via the least squares method. A newly developed canonical duality theory shows that this nonconvex minimization problem can be solved deterministically in polynomial time if a global optimality condition is satisfied. The so-called pseudo-chaos produced by linear iterative methods are mainly due to the intrinsic numerical error accumulations. Otherwise, the global optimization problem could be NP-hard and the nonlinear system can be really chaotic. A conjecture is proposed, which reveals the connection between chaos in nonlinear dynamics and NP-hardness in computer science. The methodology and the conjecture are verified by applications to the well-known logistic equation, a forced memristive circuit and the Lorenz system. Computational results show that the canonical duality theory can be used to identify chaotic systems and to obtain realistic global optimal solutions in nonlinear dynamical systems. The method and results presented in this paper should bring some new insights into nonlinear dynamical systems and NP-hardness in computational complexity theory. © 2016 World Scientific Publishing Company.