Showing items 161 - 180 of 235

Your selections:

Min-max optimal control of linear systems with uncertainty and terminal state constraints

- Wu, Changzhi, Lay Teo, Kok, Wu, Soonyi

  • Authors: Wu, Changzhi , Lay Teo, Kok , Wu, Soonyi
  • Date: 2013
  • Type: Text , Journal article
  • Relation: Automatica Vol. 49, no. 6 (2013), p. 1809-1815
  • Full Text: false
  • Reviewed:
  • Description: In this paper, a class of min-max optimal control problems with continuous dynamical systems and quadratic terminal constraints is studied. The main contribution is that the original terminal state constraint in which the disturbance is involved is transformed into an equivalent linear matrix inequality without disturbance under certain conditions. Then, the original min-max optimal control problem is solved via solving a sequence of semi-definite programming problems. An example is presented to illustrate the proposed method. © 2013 Elsevier Ltd. All rights reserved.
  • Description: 2003011022

Performance monitoring with application of reliability growth analysis

- Tam, Allen

  • Authors: Tam, Allen
  • Date: 2013
  • Type: Text , Conference paper
  • Relation: 8th World Congress on Engineering Asset Management (WCEAM 2013) & the 3rd International Conference on Utility Management & Safety (ICUMAS) p. 1281-1289
  • Full Text: false
  • Reviewed:
  • Description: Reliability growth analysis is a popular tool in monitoring reliability changes over time. The methods used include Duane plots and the Army Materiel Systems Analysis Activity (AMSAA) model. The reliability growth analysis is traditionally applied to the time domain of failure. The amplitude of failure is not considered. For equipment or processes with same MTBF should not be treated with the same priority without looking into loss of opportunity in wealth creation. This research proposes the application of reliability growth method to failure losses in unit of production loss for monitoring changes in magnitude of production loss due to failure events. In conjunction with reliability growth in time domain, a new analytical visualisation of reliability assessment, named Reliability Quadrant Graph, is proposed. This research provides a new way for high level reliability performance monitoring.

Publishing and presenting: A cross-national analysis of engineering academics in Europe

- Aarrevaara, Timo, Dobson, Ian

  • Authors: Aarrevaara, Timo , Dobson, Ian
  • Date: 2013
  • Type: Text , Journal article
  • Relation: Global Journal of Engineering Education Vol. 15, no. 3 (2013), p. 148-154
  • Full Text: false
  • Reviewed:
  • Description: The international Changing Academic Profession (CAP) survey was used to compare several measures of research output in participating European countries. When looking at the output of books, articles, reports and conference presentations, results indicated variations between countries and between the engineering field of education and other fields of education. European university engineering academics produced relatively more research reports/monographs written for a funded project, but tended to produce at lower rates than academics overall in the other three forms of written research output. © WIETE 2013.

Reliability prediction of distributed systems using Monte Carlo method

- Gunawan, Indra

  • Authors: Gunawan, Indra
  • Date: 2013
  • Type: Text , Journal article
  • Relation: International Journal of Reliability and Safety Vol. 7, no. 3 (2013), p. 235-248
  • Full Text: false
  • Reviewed:
  • Description: Distributed systems consist of layers of switching elements connected together in a predefined topology providing the connectivity between the set of processors and the set of memory modules. Reliability prediction is important as it determines the usability and efficiency of the network to provide services. This paper presents reliability analysis of Shuffle-Exchange Network (SEN) systems using Monte Carlo method with stratified sampling. A SEN, a specific type of distributed systems that consists of 2 × 2 switching elements, has been widely considered a practical interconnection system. Confidence interval of the point estimate is then derived using non-parametric bootstrapping. Copyright © 2013 Inderscience Enterprises Ltd.

Safety regulation: The lessons of workplace safety rule management for managing the regulatory burden

- Hale, Andrew, Borys, David, Adams, Mark

  • Authors: Hale, Andrew , Borys, David , Adams, Mark
  • Date: 2013
  • Type: Text , Journal article
  • Relation: Safety Science Vol. , no. (2013), p.
  • Full Text: false
  • Reviewed:
  • Description: There is a strong political consensus in a number of countries that occupational safety and health regulation is stifling industrial innovation and development and is feeding a culture of damaging risk aversion and petty bureaucracy. In a number of countries this has led to proposals to repeal regulations and reduce the regulatory burden. The authors were commissioned to prepare a discussion paper on this issue by the Mercatus Center of George Mason University in Arlington, Virginia, aimed particularly at an American audience. This paper is based on that report (Hale et al., 2011). The paper is based on previous work of the first two authors, developing a framework of occupational safety rule management at the workplace level (Hale and Borys, 2012a,b). Based on a literature study, this paper analyses the similarities and differences between rules at the workplace level and the development, use and enforcement of regulations at the national level to influence and control organisational behavior. It traces the forces encouraging the growth of regulatory detail and hence the bureaucratic burden of compliance and the options open to reduce that burden without loosening control so much that the level of safety declines. The analysis uses the hierarchy of rules from goals, through process (risk management) rules to detailed action rules as framework for predicting the level of ownership and responsibility felt by the regulated.
  • Description: C1

Social marketing: why injury prevention needs to adopt this behaviour change approach

- Newton, Joshua, Ewing, Michael, Finch, Caroline

The reach and adoption of a coach-led exercise training programme in community football

- Finch, Caroline, Diamantopoulou, Kathy, Twomey, Dara, Doyle, Tim, Lloyd, David, Young, Warren, Elliot, Bruce

  • Authors: Finch, Caroline , Diamantopoulou, Kathy , Twomey, Dara , Doyle, Tim , Lloyd, David , Young, Warren , Elliot, Bruce
  • Date: 2013
  • Type: Text , Journal article
  • Relation: British Journal of Sports Medicine. Vol. 48(8), p.718-723.
  • Relation: http://purl.org/au-research/grants/nhmrc/565900
  • Full Text:
  • Reviewed:
  • Description: Objective: To determine the reach and adoption of a coach-led exercise training programme for lower limb injury prevention. Design: Secondary analysis of data from a group-clustered randomised controlled trial. Setting: A periodised exercise training warm-up programme was delivered to players during training sessions over an 8-week preseason (weeks 1–8) and 18-week playing season. Participants: 1564 community Australian football players. Main outcome measurements: Reach, measured weekly, was the number of players who attended training sessions. Adoption was the number of attending players who completed the programme in full, partially or not at all. Reasons for partial or non-participation were recorded. Results: In week 1, 599 players entered the programme; 55% attended 1 training session and 45% attended > 1 session. By week 12, 1540 players were recruited but training attendance (reach) decreased to <50%. When players attended training, the majority adopted the full programme—ranging from 96% (week 1) to above 80% until week 20. The most common reasons for low adoption were players being injured, too sore, being late for training or choosing their own warm-up. Conclusions: The training programme's reach was highest preseason and halved at the playing season's end. However, when players attended training sessions, their adoption was high and remained close to 70% by season end. For sports injury prevention programmes to be fully effective across a season, attention also needs to be given to (1) encouraging players to attend formal training sessions and (2) considering the possibility of some form of programme delivery outside of formal training.

Understanding safety management system applicability in community sport

- Donaldson, Alex, Borys, David, Finch, Caroline

  • Authors: Donaldson, Alex , Borys, David , Finch, Caroline
  • Date: 2013
  • Type: Text , Journal article
  • Relation: Safety Science Vol. 60, no. (2013), p. 95-104
  • Relation: http://purl.org/au-research/grants/nhmrc/565907
  • Full Text:
  • Reviewed:
  • Description: Despite recent interest in understanding the implementation context for sports injury prevention interventions, little research attention has been paid to the management structures and processes of community sporting organisations. This study developed expert consensus about the importance of Occupational Health and Safety (OHS) setting-related safety management system (SMS) principles and performance indicators in the context of Australian community sporting organizations, and the feasibility of these organisations meeting the requirements for the SMS performance indicators. Twenty-nine sports injury prevention, community sports administration and OHS SMS experts participated in a three-round online Delphi study by rating the importance of 64 SMS performance indicators categorised under the five principles of Commitment and Policy; Planning; Implementation; Measurement and Evaluation; and Review and Improvement. Overall, consensus agreement - define as rated 'essential' or 'very important' on a five-point scale by ≥75% of the participants in Round 3 - was reached for 57 performance indicators. Ten (15%) performance indicators were rated as 'very difficult' or 'relatively difficult', and six (9%) were rated as 'very easy' or 'relatively easy' on a four-point scale, by ≥75% of participants. This research suggests that the guiding principles and associated performance indicators that underpin OHS safety management systems in the workplace are very relevant and applicable to community sporting organisations in Australia. However, considerable work is required to build organisational capacity to be able to develop and implement meaningfully and useful SMSs to prevent sports injuries in the most common setting in which they occur. © 2013 Elsevier Ltd. Funded by NHMRC.
  • Description: 2003011206

Understanding the violation of IS security policy in organizations: An integrated model based on social control and deterrence theory

- Cheng, Lijiao, Li, Ying, Li, Wenli, Holm, Eric, Zhai, Qingguo

  • Authors: Cheng, Lijiao , Li, Ying , Li, Wenli , Holm, Eric , Zhai, Qingguo
  • Date: 2013
  • Type: Text , Journal article
  • Relation: Computers and Security Vol. 39, no. Part B (2013), p. 447-459
  • Full Text: false
  • Reviewed:
  • Description: It is widely agreed that a large amount of information systems (IS) security incidents occur in the workplace because employees subvert existing IS Security Policy (ISSP). In order to understand the factors that constrain employees from deviance and violation of the organizational ISSP, past work has traditionally viewed this issue through the lens of formal deterrence mechanisms; we postulated that we could better explain employees' ISSP violation behaviours through considering both formal and informal control factors as well as through considering existing deterrence theory. We therefore developed a theoretical model based on both deterrence and social bond theories rooted in a social control perspective to better understand employee behaviour in this context. The model is validated using survey data of 185 employees. Our empirical results highlight that both formal and informal controls have a significant effect on employees' ISSP violation intentions. To be specific, employees' social bonding is found to have mixed impacts on the employee's intention to violate ISSP. Social pressures exerted by subjective norms and co-worker behaviours also significantly influence employees' ISSP violation intentions. In analyzing the formal sanctions, the perceived severity of sanctions was found to be significant while, perceived certainty of those sanctions was not. We discuss the key implications of our findings for managers and researchers and the implications for professional practice.

What are the most effective risk-reduction strategies in sport concussion?

- Benson, Brian, McIntosh, Andrew, Maddocks, David, Herring, Stanley, Raftery, Martin, Dvorak, Jiri

  • Authors: Benson, Brian , McIntosh, Andrew , Maddocks, David , Herring, Stanley , Raftery, Martin , Dvorak, Jiri
  • Date: 2013
  • Type: Text , Journal article
  • Relation: British Journal of Sports Medicine Vol. 47, no. 5 (2013), p. 321-326
  • Full Text: false
  • Reviewed:
  • Description: Aim To critically review the evidence to determine the efficacy and effectiveness of protective equipment, rule changes, neck strength and legislation in reducing sport concussion risk. Methods Electronic databases, grey literature and bibliographies were used to search the evidence using Medical Subject Headings and text words. Inclusion/ exclusion criteria were used to select articles for the clinical equipment studies. The quality of evidence was assessed using epidemiological criteria regarding internal/external validity (eg, strength of design, sample size/power, bias and confounding). Results No new valid, conclusive evidence was provided to suggest the use of headgear in rugby, or mouth guards in American football, significantly reduced players' risk of concussion. No evidence was provided to suggest an association between neck strength increases and concussion risk reduction. There was evidence in ice hockey to suggest fair-play rules and eliminating body checking among 11-years-olds to 12-years-olds were effective injury prevention strategies. Evidence is lacking on the effects of legislation on concussion prevention. Equipment self-selection bias was a common limitation, as was the lack of measurement and control for potential confounding variables. Lastly, helmets need to be able to protect from impacts resulting in a head change in velocities of up to 10 and 7 m/s in professional American and Australian football, respectively, as well as reduce head resultant linear and angular acceleration to below 50 g and 1500 rad/s2, respectively, to optimise their effectiveness. Conclusions A multifactorial approach is needed for concussion prevention. Future well-designed and sportspecific prospective analytical studies of sufficient power are warranted.

Yield and characteristics of pyrolysis products obtained from Schizochytrium limacinum under different temperature regimes

- Li, Gang, Zhou, Yuguang, Ji, Fang, Liu, Ying, Adhikari, Benu, Tian, Li, Ma, Zonghu, Dong, Renjie

  • Authors: Li, Gang , Zhou, Yuguang , Ji, Fang , Liu, Ying , Adhikari, Benu , Tian, Li , Ma, Zonghu , Dong, Renjie
  • Date: 2013
  • Type: Text , Journal article
  • Relation: Energies Vol. 6, no. 7 (2013), p. 3339-3352
  • Full Text: false
  • Reviewed:
  • Description: Pyrolysis-gas chromatographic mass spectrometry (Py-GC/MS) was used to determine the yield and chemical composition of the pyrolysis products of Schizochytrium limacinum. The pyrolysis was carried out by varying the temperature from 300 °C to 800 °C. It was found that the main decomposition temperature of Schizochytrium limacinum was 428.16 °C, at which up to 66.5% of the mass was lost. A further 18.7% mass loss then occurred in a relatively slow pace until 760.2 °C due to complete decomposition of the ash content of Schizochytrium limacinum. The pyrolysis of Schizochytrium limacinum at 700 °C produced the maximum yield (67.7%) of pyrolysis products compared to 61.2% at 400 °C. While pollutants released at 700 °C (12.3%) was much higher than that of 400 °C (2.1%). Higher temperature will lead to more pollutant (nitrogen compounds and PAHs) release,which is harmful to the environment. Considering the reasonably high yield and minimum release of pollutants, a lower pyrolysis temperature (400 °C) was found to be optimum for producing biofuel from Schizochytrium limacinum.
  • Description: C1

A hybrid of multiobjective evolutionary algorithm and HMM-Fuzzy model for time series prediction

- Hassan, Md Rafiul, Nath, Gupta, Kirley, Michael, Kamruzzaman, Joarder

  • Authors: Hassan, Md Rafiul , Nath, Gupta , Kirley, Michael , Kamruzzaman, Joarder
  • Date: 2012
  • Type: Text , Journal article
  • Relation: Neurocomputing Vol. 81, no. April (2012), p. 1-11
  • Full Text: false
  • Reviewed:
  • Description: In this paper, we introduce a new hybrid of Hidden Markov Model (HMM), Fuzzy Logic and multiobjective Evolutionary Algorithm (EA) for building a fuzzy model to predict non-linear time series data. In this hybrid approach, the HMM's log-likelihood score for each data pattern is used to rank the data and fuzzy rules are generated using the ranked data. We use multiobjective EA to find a range of trade-off solutions between the number of fuzzy rules and the prediction accuracy. The model is tested on a number of benchmark and more recent financial time series data. The experimental results clearly demonstrate that our model is able to generate a reduced number of fuzzy rules with similar (and in some cases better) performance compared with typical data driven fuzzy models reported in the literature.

Adaptive regulatory genes cardinality for reconstructing genetic networks

- Chowdhury, Ahsan, Chetty, Madhu, Vinh, Nguyen

  • Authors: Chowdhury, Ahsan , Chetty, Madhu , Vinh, Nguyen
  • Date: 2012
  • Type: Text , Conference paper
  • Relation: WCCI 2012 IEEE World Congress on Computational Intelligence
  • Full Text: false
  • Reviewed:
  • Description: With the advent of microarray technology, researchers are able to determine cellular dynamics for thousands of genes simultaneously, thereby enabling reverse engineering of the gene regulatory network (GRN) from high-throughput time-series gene expression data. Amongst the various currently available models for inferring GRN, the S-System formalism is often considered as an excellent compromise between accuracy and mathematical tractability. In this paper, a novel approach for inferring GRN based on the decoupled S-System model, incorporating the new concept of adaptive regulatory genes cardinality, is proposed. Parameter learning for the S-System is carried out in an evolving manner using a versatile and robust Trigonometric Evolutionary Algorithm. The applicability and efficiency of the proposed method is studied using a well-known and widely studied synthetic network with various levels of noise, and excellent performance observed. Further, investigations of a 5 gene in-vivo synthetic biological network of Saccharomyces cerevisiae called IRMA, has succeeded in detecting higher number of correct regulations compared to other approaches reported earlier.

Approaches to reporting grade uncertainty in high nugget gold veins

- Dominy, Simon, Edgar, W.

  • Authors: Dominy, Simon , Edgar, W.
  • Date: 2012
  • Type: Text , Journal article
  • Relation: Transactions of the Institutions of Mining and Metallurgy, Section B : Applied Earth Science Vol. 121, no. 1 (2012), p. 29-42
  • Full Text: false
  • Reviewed:
  • Description: High nugget effect gold veins are generally considered to be one of the most challenging of deposit types to evaluate and exploit. To potential investors and mining companies, they are viewed as high risk because of the associated uncertainties in the grade estimate and general paucity of reserves at production start-up. Despite the well-known risks, these deposits are often high grade and have a grade upside which makes them potentially attractive. The reporting of resource grade is of importance and perhaps even more so is the reporting of the associated uncertainty attached to the grade estimate. The quoting of the estimated grade within a grade range is recommended to achieve more complete and useful disclosure. The definition of the grade range can be somewhat subjective, ranging from opinion-based through to data-based estimates and geostatistical conditional simulation. Whichever approach is used, the over-riding issue must be the provision of enough data of appropriate quality and full disclosure to the public of relevant uncertainties. © 2012 Institute of Materials, Minerals and Mining and The AusIMM.
  • Description: 2003010578

Calibration of an articulated CMM using stochastic approximations

- Sultan, Ibrahim, Puthiyaveettil, Prajeesh

  • Authors: Sultan, Ibrahim , Puthiyaveettil, Prajeesh
  • Date: 2012
  • Type: Text , Journal article
  • Relation: International Journal of Advanced Manufacturing Technology Vol. 63, no. 1-4 (2012), p. 201-207
  • Full Text:
  • Reviewed:
  • Description: A coordinate measuring machine (CMM) is meant to digitise the spatial locations of points and feed the resulting measurements to a CAD system for storing and processing. For reliable utilisation of a CMM, a calibration procedure is often undertaken to eliminate the inaccuracies which result from manufacturing, assembly and installation errors. In this paper, an Immersion digitizer coordinate measuring machine has been calibrated using an accurately manufactured master cuboid fixture. This CMM has been designed as an articulated manipulator to enhance its dexterity and versatility. As such, the calibration problem is tackled with the aid of a kinematic model similar to those employed for the analysis of serial robots. In addition, a stochastic-based optimisation technique is used to identify the parameters of the kinematic model in order for the accurate performance to be achieved. The experimental results demonstrate the effectiveness of this method, whereby the measuring accuracy has been improved considerably. © 2012 Springer-Verlag London Limited.
  • Description: 2003010394

Coding OSICS sports injury diagnoses in epidemiological studies : Does the background of the coder matter?

- Finch, Caroline, Orchard, John, Twomey, Dara, Saleem, Muhammad Saad, Ekegren, Christina, Lloyd, David, Elliott, Bruce

  • Authors: Finch, Caroline , Orchard, John , Twomey, Dara , Saleem, Muhammad Saad , Ekegren, Christina , Lloyd, David , Elliott, Bruce
  • Date: 2012
  • Type: Text , Journal article
  • Relation: British Journal of Sports Medicine, Vol.48, p.552-556.
  • Relation: http://purl.org/au-research/grants/nhmrc/565900
  • Full Text:
  • Reviewed:
  • Description: Objective: To compare Orchard Sports Injury Classification System (OSICS-10) sports medicine diagnoses assigned by a clinical and non-clinical coder. Design: Assessment of intercoder agreement. Setting: Community Australian football. Participants: 1082 standardised injury surveillance records. Main outcome measurements: Direct comparison of the four-character hierarchical OSICS-10 codes assigned by two independent coders (a sports physician and an epidemiologist). Adjudication by a third coder (biomechanist). Results: The coders agreed on the first character 95% of the time and on the first two characters 86% of the time. They assigned the same four-digit OSICS-10 code for only 46% of the 1082 injuries. The majority of disagreements occurred for the third character; 85% were because one coder assigned a non-specific 'X' code. The sports physician code was deemed correct in 53% of cases and the epidemiologist in 44%. Reasons for disagreement included the physician not using all of the collected information and the epidemiologist lacking specific anatomical knowledge. Conclusions: Sports injury research requires accurate identification and classification of specific injuries and this study found an overall high level of agreement in coding according to OSICS-10. The fact that the majority of the disagreements occurred for the third OSICS character highlights the fact that increasing complexity and diagnostic specificity in injury coding can result in a loss of reliability and demands a high level of anatomical knowledge. Injury report form details need to reflect this level of complexity and data management teams need to include a broad range of expertise. Copyright Article author (or their employer) 2012.

Compliance with return-to-play regulations following concussion in Australian schoolboy and community rugby union players

- Hollis, Stephanie, Stevenson, Mark, McIntosh, Andrew, Shores, E Arthur, Finch, Caroline

  • Authors: Hollis, Stephanie , Stevenson, Mark , McIntosh, Andrew , Shores, E Arthur , Finch, Caroline
  • Date: 2012
  • Type: Text , Journal article
  • Relation: British Journal of Sports Medicine Vol. 46, no. 10 (2012), p. 735-740
  • Full Text: false
  • Reviewed:
  • Description: Background: There is a risk of concussion when playing rugby union. Appropriate management of concussion includes compliance with the return-to-play regulations of the sports body for reducing the likelihood of premature return-to-play by injured players. Purpose: To describe the proportion of rugby union players who comply with the sports body's regulations on returning to play postconcussion. Study design: Prospective cohort study. Methods: 1958 community rugby union players (aged 15–48 years) in Sydney (Australia) were recruited from schoolboy, grade and suburban competitions and followed over ≥1 playing seasons. Club doctors/physiotherapists/coaches or trained injury recorders who attended the game reported players who sustained a concussion. Concussed players were followed up over a 3-month period and the dates when they returned to play (including either a game or training session) were recorded, as well as any return-to-play advice they received. Results: 187 players sustained ≥1 concussion throughout the follow-up. The median number of days before players returned to play (competition game play or training) following concussion was 3 (range 1–84). Most players (78%) did not receive return-to-play advice postconcussion, and of those who received correct advice, all failed to comply with the 3-week stand-down regulation. Conclusions: The paucity of return-to-play advice received by community rugby union players postconcussion and the high level of non-compliance with return-to-play regulations highlight the need for better dissemination and implementation of the return-to-play regulations and improved understanding of the underlying causes of why players do not adhere to return-to-play practices.

Controls on the rate of ureolysis and the morphology of carbonate precipitated by S. Pasteurii biofilms and limits due to bacterial encapsulation

- Cuthbert, M., Riley, Michael, Handley-Sidhu, Stephanie, Renshaw, Joanna, Tobler, Dominique, Phoenix, Vernon, Mackay, Rae

  • Authors: Cuthbert, M. , Riley, Michael , Handley-Sidhu, Stephanie , Renshaw, Joanna , Tobler, Dominique , Phoenix, Vernon , Mackay, Rae
  • Date: 2012
  • Type: Text , Journal article
  • Relation: Ecological Engineering Vol. 41, no. (2012), p. 32-40
  • Full Text: false
  • Reviewed:
  • Description: Despite the potential contribution of microbially induced carbonate precipitation (MICP) to a range of environmental technologies, little is known about the controls on the rate of ureolysis and precipitate size and morphology using attached bacterial communities. This paper presents results of experiments using Sporosarcina pasteurii biofilms, of varying density, grown on perspex and granite surfaces then immersed in fluids comprising calcium chloride and urea of varying concentrations. Denser biofilms resulting from higher nutrient conditions led to faster nucleation of calcite and higher rates of ammonium production found to be related to crystal size via a power law. The observed morphology of the precipitates was variable depending on precipitation rates and nucleation of calcite was independent of the substrate mineralogy. In some cases the calcite layer became non-porous, and the bridging of pores within the granite was also observed. We show how ureolysis is limited eventually by the encapsulation of the biofilm by calcite and present a novel model that enables the reaction to be optimised to yield maximum calcite precipitation over a desired timescale. Slower reaction rates may in some circumstances be desirable for maximum reaction efficiency. The results have important implications for the design of engineering solutions involving MICP

Detecting K-complexes for sleep stage identification using nonsmooth optimization

- Moloney, David, Sukhorukova, Nadezda, Vamplew, Peter, Ugon, Julien, Li, Gang, Beliakov, Gleb, Philippe, Carole, Amiel, Hélène, Ugon, Adrien

  • Authors: Moloney, David , Sukhorukova, Nadezda , Vamplew, Peter , Ugon, Julien , Li, Gang , Beliakov, Gleb , Philippe, Carole , Amiel, Hélène , Ugon, Adrien
  • Date: 2012
  • Type: Text , Journal article
  • Relation: ANZIAM Journal Vol. 52, no. 4 (2012), p. 319-332
  • Full Text:
  • Reviewed:
  • Description: The process of sleep stage identification is a labour-intensive task that involves the specialized interpretation of the polysomnographic signals captured from a patient's overnight sleep session. Automating this task has proven to be challenging for data mining algorithms because of noise, complexity and the extreme size of data. In this paper we apply nonsmooth optimization to extract key features that lead to better accuracy. We develop a specific procedure for identifying K-complexes, a special type of brain wave crucial for distinguishing sleep stages. The procedure contains two steps. We first extract "easily classified" K-complexes, and then apply nonsmooth optimization methods to extract features from the remaining data and refine the results from the first step. Numerical experiments show that this procedure is efficient for detecting K-complexes. It is also found that most classification methods perform significantly better on the extracted features. © 2012 Australian Mathematical Society.

Do parents' and children's concerns about sports safety and injury risk relate to how much physical activity children do?

- Telford, Amanda, Finch, Caroline, Barnett, Lisa, Abbott, Gavin, Salmon, Jo

  • Authors: Telford, Amanda , Finch, Caroline , Barnett, Lisa , Abbott, Gavin , Salmon, Jo
  • Date: 2012
  • Type: Text , Journal article
  • Relation: British Journal of Sports Medicine Vol. 46, no. 15 (2012), p. 1084-1088
  • Relation: http://purl.org/au-research/grants/nhmrc/565900
  • Full Text: false
  • Reviewed:
  • Description: Objective: To see whether concerns about injury risk relate to children's physical activity (PA). Methods: Two cohorts were recruited from 19 Australian schools and assessed in 2001 (T1), 2004 (T2) and 2006 (T3). The younger (n=162) was assessed at 6, 9 and 11years old, and the older (n=259) at 11, 14 and 16 years old. At T1 and T2, parents of the younger cohort reported on fear of child being injured, and whether child would be at risk of injury if they played organised sport; the older cohort self-reported injury fear. Accelerometers assessed PA at each time point. Linear regression models examined cross-sectional associations, and also associations between T1 injury fear and risk and T2 PA, and T2 injury fear and risk and T3 PA. Results: In the younger cohort at T2 (9 years), fear and risk were both negatively associated with moderate to vigorous PA (MVPA) (β=−0.17, 95% CI −0.30 to −0.03 and β=−0.26, 95% CI −0.41 to −0.10) and also vigorous PA (VPA). Fear was also associated with moderate PA (MPA). For the older cohort at T1, injury fear was negatively associated with MVPA (β=−0.21, 95% CI −0.35 to −0.07) and also MPA and VPA. Parental perception of risk at T1 (6 years) was negatively associated with children’s MPA at T2 (9 years) (β= −0.17, 95% CI −0.32 to −0.02). Sex did not moderate any association. Conclusions Younger children and their parents need to know which sports have low injury risks. Some children may need increased confidence to participate.
  • Description: Objective: To see whether concerns about injury risk relate to children's physical activity (PA). Methods: Two cohorts were recruited from 19 Australian schools and assessed in 2001 (T1), 2004 (T2) and 2006 (T3). The younger (n=162) was assessed at 6, 9 and 11years old, and the older (n=259) at 11, 14 and 16 years old. At T1 and T2, parents of the younger cohort reported on fear of child being injured, and whether child would be at risk of injury if they played organised sport; the older cohort self-reported injury fear. Accelerometers assessed PA at each time point. Linear regression models examined cross-sectional associations, and also associations between T1 injury fear and risk and T2 PA, and T2 injury fear and risk and T3 PA. Results: In the younger cohort at T2 (9 years), fear and risk were both negatively associated with moderate to vigorous PA (MVPA) (