Showing papers in "Ergonomics in 2012"
TL;DR: A strategy for the HFE community to strengthen demand and application of high-quality HFE, emphasising its key elements: systems approach, design driven, and performance and well-being goals is presented.
Abstract: Human factors/ergonomics (HFE) has great potential to contribute to the design of all kinds of systems with people (work systems, product/service systems), but faces challenges in the readiness of ...
682 citations
TL;DR: Recent literature and a conceptual model highlighting s/g differences in physical and functional characteristics related to neck/shoulder musculoskeletal disorders (NSMSD) are critically reviewed and have implications on understanding how personal factors may affect NSMSD risk.
Abstract: The objective of this paper is to critically review recent literature on physical and functional sex/gender (s/g) differences, with focus on physical determinants associated with neck/shoulder musculoskeletal injuries. It is well known that there are s/g differences in anthropometrical and functional body characteristics (e.g. size and strength). However, s/g differences may be wrongly attributed if data analysis does not include appropriate corrections (e.g. by strength for endurance). Recent literature on motor control shows that there may indeed be s/g differences in muscle coordination and movement strategies during upper limb tasks that are not currently explained by methodological inadequacies. Moreover, recent studies have shown differences between men and women in sensory hypersensitivity characteristics associated with neck/shoulder injuries. Taken together, the literature points to the importance of accounting for possible s/g differences at all levels of the biopsychosocial system in order to b...
191 citations
TL;DR: The design of decision-support aids on consumer devices (e.g. smartphones) may influence the level of trust that users place in that system and their amount of use, and how the design of aids may influence user's trust and use of such systems is articulated.
Abstract: This study examined the use of deliberately anthropomorphic automation on younger and older adults' trust, dependence and performance on a diabetes decision-making task. Research with anthropomorphic interface agents has shown mixed effects in judgments of preferences but has rarely examined effects on performance. Meanwhile, research in automation has shown some forms of anthropomorphism (e.g. etiquette) have effects on trust and dependence on automation. Participants answered diabetes questions with no-aid, a non-anthropomorphic aid or an anthropomorphised aid. Trust and dependence in the aid was measured. A minimally anthropomorphic aide primarily affected younger adults' trust in the aid. Dependence, however, for both age groups was influenced by the anthropomorphic aid. Automation that deliberately embodies person-like characteristics can influence trust and dependence on reasonably reliable automation. However, further research is necessary to better understand the specific aspects of the aid that a...
152 citations
TL;DR: This study demonstrates that in car music listening influences mood which in turn can impact driving behaviour, and shows that listening to music can positively impact mood while driving, which can be used to affect state and safe behaviour.
Abstract: Mood can influence our everyday behaviour and people often seek to reinforce, or to alter their mood, for example by turning on music. Music listening while driving is a popular activity. However, little is known about the impact of music listening while driving on physiological state and driving performance. In the present experiment, it was investigated whether individually selected music can induce mood and maintain moods during a simulated drive. In addition, effects of positive, negative, and no music on driving behaviour and physiological measures were assessed for normal and high cognitive demanding rides. Subjective mood ratings indicated that music successfully maintained mood while driving. Narrow lane width drives increased task demand as shown in effort ratings and increased swerving. Furthermore, respiration rate was lower during music listening compared to rides without music, while no effects of music were found on heart rate. Overall, the current study demonstrates that music listening in car influences the experienced mood while driving, which in turn can impact driving behaviour. PRACTITIONERS SUMMARY: Even though it is a popular activity, little is known about the impact of music while driving on physiological state and performance. We examined whether music can induce moods during high and low simulated drives. The current study demonstrates that in car music listening influences mood which in turn can impact driving behaviour. The current study shows that listening to music can positively impact mood while driving, which can be used to affect state and safe behaviour. Additionally, driving performance in high demand situations is not negatively affected by music.
104 citations
TL;DR: A conceptual framework that can support efforts to integrate human factors (HF) into the work system design process, where improved and cost-effective application of HF is possible.
Abstract: This paper presents a conceptual framework that can support efforts to integrate human factors (HF) into the work system design process, where improved and cost-effective application of HF is possible. The framework advocates strategies of broad stakeholder participation, linking of performance and health goals, and process focussed change tools that can help practitioners engage in improvements to embed HF into a firm's work system design process. Recommended tools include business process mapping of the design process, implementing design criteria, using cognitive mapping to connect to managers’ strategic goals, tactical use of training and adopting virtual HF (VHF) tools to support the integration effort. Consistent with organisational change research, the framework provides guidance but does not suggest a strict set of steps. This allows more adaptability for the practitioner who must navigate within a particular organisational context to secure support for embedding HF into the design process for imp...
99 citations
TL;DR: The traditional method of bra fitting was found to be inadequate, especially for larger-breasted women; the use of professional bra fitting criteria should be encouraged.
Abstract: A correctly fitting bra is essential for good health; this study investigates the use of professional bra fitting criteria to establish best-fit in an underwire bra commonly sold in the UK. A comparison was made between women's bra size as measured by the traditional bra fitting method with their recommended bra size based on professional bra fitting criteria. Forty-five female participants were recruited; their mode self-reported bra size was 34DD. Participants were measured in their own bra using the traditional bra-fitting method to establish their ‘traditional size’. A ‘best-fit’ bra size was recorded for participants based on professional bra fitting criteria. Significant differences were found between traditional and best-fit cup and band sizes (p < 0.001); the traditional method of bra fitting overestimated band size and underestimated cup size. As band size increased the traditional method also became more inaccurate (p < 0.001). It is recommended that women are educated in assessing their own bra...
93 citations
TL;DR: This study assesses usability and experimentation factors of two commercial BCI models, for the purpose of creating basic guidelines for increased usability, and finds that more sensors can be less comfortable and accurate than devices with fewer sensors.
Abstract: The use of brain computer interface (BCI) devices in research and applications has exploded in recent years. Applications such as lie detectors that use functional magnetic resonance imaging (fMRI) to video games controlled using electroencephalography (EEG) are currently in use. These developments, coupled with the emergence of inexpensive commercial BCI headsets, such as the Emotiv EPOC ( http://emotiv.com/index.php ) and the Neurosky MindWave, have also highlighted the need of performing basic ergonomics research since such devices have usability issues, such as comfort during prolonged use, and reduced performance for individuals with common physical attributes, such as long or coarse hair. This paper examines the feasibility of using consumer BCIs in scientific research. In particular, we compare user comfort, experiment preparation time, signal reliability and ease of use in light of individual differences among subjects for two commercially available hardware devices, the Emotiv EPOC and the Neurosky MindWave. Based on these results, we suggest some basic considerations for selecting a commercial BCI for research and experimentation. STATEMENT OF RELEVANCE: Despite increased usage, few studies have examined the usability of commercial BCI hardware. This study assesses usability and experimentation factors of two commercial BCI models, for the purpose of creating basic guidelines for increased usability. Finding that more sensors can be less comfortable and accurate than devices with fewer sensors.
93 citations
TL;DR: Human factor issues involved in designing and evaluating brain–computer interface (BCI) systems for users with severe motor disabilities are explored using participatory research paradigms and qualitative methods.
Abstract: Brain–computer interfaces (BCI) are designed to enable individuals with severe motor impairments such as amyotrophic lateral sclerosis (ALS) to communicate and control their environment A focus group was conducted with individuals with ALS (n=8) and their caregivers (n=9) to determine the barriers to and mediators of BCI acceptance in this population Two key categories emerged: personal factors and relational factors Personal factors, which included physical, physiological and psychological concerns, were less important to participants than relational factors, which included corporeal, technological and social relations with the BCI The importance of these relational factors was analysed with respect to published literature on actor-network theory (ANT) and disability, and concepts of voicelessness and personhood Future directions for BCI research are recommended based on the emergent focus group themes Practitioner Summary: This manuscript explores human factor issues involved in designing and eval
93 citations
TL;DR: It is indicated that product aesthetics influences perceived usability considerably in one-off usability tests but this influence wanes over time, and it is therefore advisable to adopt a longitudinal multiple-session approach to reduce the possibly undesirable influence of aesthetics on usability ratings.
Abstract: A longitudinal field experiment was carried out over a period of 2 weeks to examine the influence of product aesthetics and inherent product usability. A 2 × 2 × 3 mixed design was used in the study, with product aesthetics (high/low) and usability (high/low) being manipulated as between-subjects variables and exposure time as a repeated-measures variable (three levels). A sample of 60 mobile phone users was tested during a multiple-session usability test. A range of outcome variables was measured, including performance, perceived usability, perceived aesthetics and emotion. A major finding was that the positive effect of an aesthetically appealing product on perceived usability, reported in many previous studies, began to wane with increasing exposure time. The data provided similar evidence for emotion, which also showed changes as a function of exposure time. The study has methodological implications for the future design of usability tests, notably suggesting the need for longitudinal approaches in us...
89 citations
TL;DR: Data suggest that the TLV for HAL and the SI are useful metrics for estimating exposure to biomechanical stressors for estimating risk of carpal tunnel syndrome when adjusted for relevant covariates.
Abstract: A cohort of 536 workers was enrolled from 10 diverse manufacturing facilities and was followed monthly for six years. Job physical exposures were individually measured. Worker demographics, medical history, psychosocial factors, current musculoskeletal disorders (MSDs) and nerve conduction studies (NCS) were obtained. Point and lifetime prevalence of carpal tunnel syndrome (CTS) at baseline (symptoms + abnormal NCS) were 10.3% and 19.8%. During follow-up, there were 35 new CTS cases (left, right or both hands). Factors predicting development of CTS included: job physical exposure (American conference of governmental industrial hygienists Threshold Limit Value (ACGIH TLV) for Hand Activity Level (HAL) and the Strain Index (SI)), age, BMI, other MSDs, inflammatory arthritis, gardening outside of work and feelings of depression. In the adjusted models, the TLV for HAL and the SI were both significant per unit increase in exposure with hazard ratios (HR) increasing up to a maximum of 5.4 (p = 0.05) and 5.3 (p...
89 citations
TL;DR: The GeoSpell interface (Geometric Speller) is introduced, which implements a stimulation framework for a P300-based BCI that has been optimised for operation in covert visual attention and far exceeded the threshold of accuracy with regard to effective spelling.
Abstract: The Farwell and Donchin P300 speller interface is one of the most widely used brain–computer interface (BCI) paradigms for writing text. Recent studies have shown that the recognition accuracy of the P300 speller decreases significantly when eye movement is impaired. This report introduces the GeoSpell interface (Geometric Speller), which implements a stimulation framework for a P300-based BCI that has been optimised for operation in covert visual attention. We compared the Geospell with the P300 speller interface under overt attention conditions with regard to effectiveness, efficiency and user satisfaction. Ten healthy subjects participated in the study. The performance of the GeoSpell interface in covert attention was comparable with that of the P300 speller in overt attention. As expected, the effectiveness of the spelling decreased with the new interface in covert attention. The NASA task load index (TLX) for workload assessment did not differ significantly between the two modalities. Practitioner Su...
TL;DR: The present study conducted to review the literature on the methods that have been considered appropriate for evaluation of the effects of gloves on different aspects of hand performance, to make recommendations for the testing and assessment of gloves, and to identify where further research is needed to improve the evaluation protocols.
Abstract: The present study was conducted to review the literature on the methods that have been considered appropriate for evaluation of the effects of gloves on different aspects of hand performance, to make recommendations for the testing and assessment of gloves, and to identify where further research is needed to improve the evaluation protocols. Eighty-five papers meeting the criteria for inclusion were reviewed. Many studies show that gloves may have negative effects on manual dexterity, tactile sensitivity, handgrip strength, muscle activity and fatigue and comfort, while further research is needed to determine glove effects on pinch strength, forearm torque strength and range of finger and wrist movements. The review also highlights several methodological issues (including consideration of both task type and duration of glove use by workers, guidance on the selection and allocation of suitable glove(s) for particular tasks/jobs, and glove design features) that need to be considered in future research. Practitioner Summary: The relevant literature on the effects of protective gloves on different aspects of hand performance was reviewed to make recommendations for the testing and assessment of gloves, and to improve evaluation protocols. The review highlights research areas and methodological issues that need to be considered in future research.
TL;DR: The first one was found as more sustainable in terms of accuracy and cognitive effort than the icon-speller, designed to operate smart home environment or to communicate moods and needs.
Abstract: Brain–computer interface (BCI) systems aim to enable interaction with other people and the environment without muscular activation by the exploitation of changes in brain signals due to the execution of cognitive tasks. In this context, the visual P300 potential appears suited to control smart homes through BCI spellers. The aim of this work is to evaluate whether the widely used character-speller is more sustainable than an icon-based one, designed to operate smart home environment or to communicate moods and needs. Nine subjects with neurodegenerative diseases and no BCI experience used both speller types in a real smart home environment. User experience during BCI tasks was evaluated recording concurrent physiological signals. Usability was assessed for each speller type immediately after use. Classification accuracy was lower for the icon-speller, which was also more attention demanding. However, in subjective evaluations, the effect of a real feedback partially counterbalanced the difficulty in BCI u...
TL;DR: It was showed that working memory, choice reaction time and executive function declined during exposure to 10°C air, and these impairments persisted 60 min into the rewarming period (i.e. once measurable physiological parameters had returned to normal).
Abstract: Several industries experience periods of cold exposure and rewarming throughout the workday but mental performance under these conditions is unknown. A better understanding of cognition during the rewarming phase after cold exposure may help reduce accidents and improve performance. Ten young men (wearing ∼0.1 clo) underwent three consecutive mornings trials where they were exposed to cold air (10°C) and then subsequently rewarmed (25°C air). A computerised test battery was administered during each stage of the protocol to determine working memory, choice reaction time, executive function and maze navigation. Rectal and skin temperature, oxygen consumption and thermal sensation were also measured throughout and showed a typical response. Relative to baseline performance, working memory, choice reaction time and executive function declined during exposure to 10°C, and these impairments persisted 60 min into the recovery period (i.e. once physiological parameters had returned to baseline). Further work is n...
TL;DR: Evidence is provided for the importance of cognitive demand in mitigating monotony-related effects on performance and demonstrate that these detrimental performance effects can be overcome with simple solutions, such as making the task more cognitively engaging.
Abstract: Although monotony is widely recognised as being detrimental to performance, its occurrence and effects are not yet well understood. This is despite the fact that task-related characteristics, such as monotony and low task demand, have been shown to contribute to performance decrements over time. Participants completed one of two simulated train-driving scenarios. Both were highly monotonous and differed only in terms of the level of cognitive demand required (i.e. low demand or high demand). These results highlight the seriously detrimental effects of the combination of monotony and low task demands and clearly show that even a relatively minor increase in cognitive demand can mitigate adverse monotony-related effects on performance for extended periods of time. Monotony is an inherent characteristic of transport industries, including rail, aviation and road transport, which can have adverse impact on safety, reliability and efficiency. This study highlights possible strategies for mitigating these advers...
TL;DR: Prolonged standing at work may be a more important risk factor for varicose veins and nocturnal leg cramps than biological differences between women and men, and effective interventions to interrupt or reduce prolongedStanding at work should be implemented for the prevention of varicOSE veins andNocturnal legs cramps.
Abstract: The relationships between occupational characteristics and symptoms of varicose veins and nocturnal leg cramps and their gender differences were explored in a Korean population. The study population was 2165 workers from various occupations (55.6% female). Multiple logistic regression analyses were conducted to reveal factors related to symptoms of varicose veins and nocturnal leg cramps. The prevalence of varicose veins and nocturnal leg cramps was higher among women than men. The characteristics of standing work were different according to gender. In gender stratified analysis, the odds ratio of varicose veins was significantly high for prolonged standing for male and female workers. However, the odds ratio of nocturnal leg cramps was only significant among prolonged standing male workers. The models including gender, prolonged standing and occupations in this order presented that gender is not significantly associated with varicose veins after occupations were added to the model. Prolonged standing at ...
TL;DR: Sitting on a novel dynamic chair resulted in less lumbar flexion and less back muscle activation than sitting on a standard backless office chair during a typing task among pain-free participants.
Abstract: Low back pain (LBP) is a common musculoskeletal disorder and prolonged sitting often aggravates LBP. A novel dynamic ergonomic chair (‘Back App’), which facilitates less hip flexion while sitting on an unstable base has been developed. This study compared lumbar posture and trunk muscle activation on this novel chair with a standard backless office chair. Twelve painfree participants completed a typing task on both chairs. Lumbar posture and trunk muscle activation were collected simultaneously and were analysed using paired t-tests. Sitting on the novel dynamic chair significantly (p 0.05) between chairs. Maintaining lordosis with less muscle activation during prolonged sitting could reduce the fatigue associated with upright sitting postures. Studies with longer sitting durations, and in people with LBP, are required. Practitioner Summa...
TL;DR: It was showed that measurement of the totality of the forces exerted at the hand/handle interface is needed to better understand the ergonomics of handle tools.
Abstract: The objective of this study was to analyse the effect of the handle diameter on the grip forces exerted by the hand during a maximal power grip task. A handle ergometer, combining six instrumented beams and a pressure map, was used to determine the forces exerted by the palm side of the hand regrouping data from 10 anatomical sites (fingertips, phalanges, thumb, palm…). This methodology provided results giving new insight into the effect of the handle diameter on the forces exerted by the hand. First, it appeared that the relationship between the hand length/handle diameter ratio and the maximal grip force fit a U-inverted curve with maximal values observed for a handle diameter measuring 17.9% of the hand length. Second, it was showed that the handle diameter influenced the forces exerted on the anatomical sites of the hand. Finally, it was showed that the handle diameter influenced the finger force sharing particularly for the index and the little fingers. Practitioner Summary: This study analysed the effect of the handle diameter on the grip forces exerted by the hand during a maximal power grip force. This study showed that measurement of the totality of the forces exerted at the hand/handle interface is needed to better understand the ergonomics of handle tools. Our results could be re-used by designers and clinicians in order to develop handle tools which prevent hand pathologies.
TL;DR: This driving-simulator study provides the first experimental evidence to explain the role of risk-feeling and lateral control in headway reduction and is valuable for devising effective driver assistance and support systems.
Abstract: Drivers in fog tend to maintain short headways, but the reasons behind this phenomenon are not well understood. This study evaluated the effect of headway on lateral control and feeling of risk in both foggy and clear conditions. Twenty-seven participants completed four sessions in a driving simulator: clear automated (CA), clear manual (CM), fog automated (FA) and fog manual (FM). In CM and FM, the drivers used the steering wheel, throttle and brake pedals. In CA and FA, a controller regulated the distance to the lead car, and the driver only had to steer. Drivers indicated how much risk they felt on a touchscreen. Consistent with our hypothesis, feeling of risk and steering activity were elevated when the lead car was not visible. These results might explain why drivers adopt short headways in fog. Practitioner Summary: Fog poses a serious road safety hazard. Our driving-simulator study provides the first experimental evidence to explain the role of risk-feeling and lateral control in headway reduction. These results are valuable for devising effective driver assistance and support systems.
TL;DR: Overall, the evidence suggests that dynamic sitting approaches are not effective as a stand-alone management approach for LBP.
Abstract: Dynamic sitting has been proposed to reduce low back pain (LBP) and/or low back discomfort (LBD) while sitting. This is supported by studies suggesting that subjects with LBP assume more static, sustained postures while sitting. This systematic review investigated the effect of dynamic sitting on LBP among subjects with LBP and the development of LBD among pain-free subjects. Electronic databases were searched by two independent assessors. All prospective studies which compared the effect of a dynamic sitting condition on LBP or LBD to another sitting condition were eligible, with no minimum follow-up period applied. The quality of the included studies was assessed using the PEDro scale. Seven high-quality studies were eligible, including five crossover studies and two randomised controlled trials. The results suggest there is currently no evidence to support the use of dynamic sitting as a stand-alone approach in the management of LBP. Practitioner Summary: This systematic review investigated the effect ...
TL;DR: Lifting height and weight lifted had more effect size than expertise on external back loading variables but expertise was a major determinant in back posture.
Abstract: The objective of this study was to measure the effect size of three important factors in manual material handling, namely expertise, lifting height and weight lifted The effect of expertise was evaluated by contrasting 15 expert and 15 novice handlers, the effect of the weight lifted with a 15-kg box and a 23-kg box and the effect of lifting height with two different box heights: ground level and a 32 cm height The task consisted of transferring a series of boxes from a conveyor to a hand trolley Lifting height and weight lifted had more effect size than expertise on external back loading variables (moments) while expertise had low impact On the other hand, expertise showed a significant effect of posture variables on the lumbar spine and knees All three factors are important, but for a reduction of external back loading, the focus should be on the lifting height and weight lifted Practitioner Summary The objective was to measure the effect size of three important factors in a transfer of boxes from
TL;DR: It was concluded that, as load mass and distance increased, female hikers modified their gait to attenuate the lower limb impact forces, however, changes aimed at attenuating the higher GRF may result in a less stable gait when carrying 30% and 40% BW loads.
Abstract: The effect of load carriage on female recreational hikers has received little attention. This study collected lower limb sagittal plane kinematic, spatio-temporal and ground reaction force (GRF) data from 15 female hikers carrying four loads (0%, 20%, 30% and 40% body weight (BW)) over 8 km. Increasing load resulted in a proportional increase in GRF up to 30% BW, increased stance time, and greater mediolateral impulse with 30% and 40% BW. Also seen were decreased velocity and cadence and increased double support and knee flexion when carrying load compared to no load. Increased distance resulted in increased knee flexion and ankle plantar flexion at initial foot–ground contact. It was concluded that, as load mass and distance increased, female hikers modified their gait to attenuate the lower limb impact forces. When carrying 30% and 40% BW loads, however, the changes aimed at attenuating the higher GRF may result in a less stable gait. Practitioner Summary: Limited research has investigated the biomechan...
TL;DR: This book was not persuaded by the attempts of a number of authors in the book to draw parallels between humans and dogs nor the efforts made to explain dog behaviour/actions/reactions in the same context as human responses.
Abstract: Canine ergonomics: the science of working dogs, by William S. Helton, Boca Raton, FL, CRC Press, 2009, 348 pp., £58.99 (hardback), ISBN 978-1-4200-7991-3 I was intrigued when I saw the title of thi...
TL;DR: It is shown that ultra-rapid judgements are connected with low- but not with high-spatial frequencies, which are neurologically processed in different visual pathways.
Abstract: This study investigates how aesthetic website evaluations, especially those formed after very brief presentations, depend on visual information that is encoded in low- or high-spatial frequencies. A total of 92 participants took part in the experiment. The study used a 3 × 3 mixed design in which presentation time (50, 500 and 10000 ms) and spatial filtering (low-pass filtered, high-pass filtered and unfiltered stimuli) were manipulated. First, we replicate prior results from online studies of high- and low-spatial frequencies. Second, we confirm a prediction from neurocognitive models that only low-spatial frequencies are relevant to aesthetic judgements in ultra-rapid presentation modes. Third, we demonstrate that stimulus repetitions lead to an overestimation of the importance of ultra-rapid stimulus presentations. Taken together, our results highlight the utility of neurocognitive models of visual processing to explain the rapid aesthetic evaluation of websites. Practitioner Summary: Using neurocognit...
TL;DR: The role of women in homemaking activities is explored together with physical exposures leading to reported symptoms, adding a perspective of a Middle Eastern context to the literature of women's musculoskeletal health.
Abstract: This study explores the relationship between housework and musculoskeletal symptoms among homemakers, adjusting for social, demographic and economic factors. A cross-sectional survey was carried out on 435 women from Nabaa, a low-income community in Lebanon. In total, 77% of women reported having musculoskeletal pain in the previous 12 months. Both psychosocial and physical factors showed significant associations with musculoskeletal symptoms. Related psychosocial factors included feelings of stress associated with homemaking and homemakers' number of children and self-rated health. The physical factors associated with musculoskeletal pain were feeling fatigued at the end of a housework day, working long hours and working in awkward postures or frequently engaging in repetitive hand movements. Ergonomic stressors were also associated with pain in the back and upper and lower extremities. Women from this community engage in a large number of hours of housework that, alongside other factors, were associated...
TL;DR: The TLX is an effective tool for comparing subjective workload between BCI tasks, participant groups (able-bodied and disabled), and control modalities and can inform the design of BCIs that will have greater usability.
Abstract: It is not well understood how people perceive the difficulty of performing brain–computer interface (BCI) tasks, which specific aspects of mental workload contribute the most, and whether there is a difference in perceived workload between participants who are able-bodied and disabled. This study evaluated mental workload using the NASA Task Load Index (TLX), a multi-dimensional rating procedure with six subscales: Mental Demands, Physical Demands, Temporal Demands, Performance, Effort, and Frustration. Able-bodied and motor disabled participants completed the survey after performing EEG-based BCI Fitts' law target acquisition and phrase spelling tasks. The NASA-TLX scores were similar for able-bodied and disabled participants. For example, overall workload scores (range 0–100) for 1D horizontal tasks were 48.5 (SD = 17.7) and 46.6 (SD 10.3), respectively. The TLX can be used to inform the design of BCIs that will have greater usability by evaluating subjective workload between BCI tasks, participant grou...
TL;DR: It is demonstrated that cleaning workers who perform the task of vacuum cleaning are at risk of work-related upper-limb musculoskeletal injury, regardless of whether they use a back-pack or canister machine.
Abstract: This study aimed to examine the risk of work-related upper-limb musculoskeletal disorders in cleaning workers during the work task of vacuuming. In total, 24 cleaning workers were observed while they performed vacuum cleaning tasks in the normal course of their employment in government schools, hospitality and commercial office space sectors. Risk of upper-limb musculoskeletal disorders were rated using three observational assessment tools: Manual Task Risk Assessment (ManTRA); Quick Exposure Check (QEC); the Rapid Upper Limb Assessment (RULA). Mean results (e.g. ManTRA wrist/hand cumulative wrist score 18.67 ± 1.27, QEC neck score 13 ± 1.77, RULA score 6.54 ± 0.509) demonstrated that cleaning workers who perform the task of vacuum cleaning are at risk of work-related upper-limb musculoskeletal injury, regardless of whether they use a back-pack or canister machine. Government school cleaners experienced greater risk of work-related upper-limb musculoskeletal disorders than workers in either the hospitalit...
TL;DR: The design aspects of the various components of a shoe from mass manufacturing to personalized shoes and components are outlined and algorithms and empirical models for footwear design are presented.
Abstract: It is widely accepted that there is no single test available which has the capacity to measure all aspects of balance performance. Many footwear intervention studies have used a package of balance assessment tools to explore the effects of shoes or insoles on postural stability. Similarly, there appears to be no single stability outcome measure that is sufficiently robust or sensitive to represent overall static or dynamic balance performance. This chapter provides an overview of postural stability assessment techniques and outcome measures commonly used in previous studies exploring the effects of footwear and shoe insole design on static or dynamic balance control; however, this list is not exhaustive. The chapter concludes presenting a selection of current literature reporting the effect of footwear interventions on postural stability in chronic conditions including Parkinson’s disease, multiple sclerosis, diabetes, and osteoarthritis. The summary is intended to highlight the relevance of postural stability assessment and footwear in clinical practice.
TL;DR: Computer users may develop musculoskeletal disorders due to their force, muscle effort, posture and wrist velocity and acceleration exposures during computer use because many physical exposures are different across computer activities.
Abstract: This study, a part of the PRedicting Occupational biomechanics in OFfice workers (PROOF) study, investigated whether there are differences in field-measured forces, muscle efforts, postures, velocities and accelerations across computer activities. These parameters were measured continuously for 120 office workers performing their own work for two hours each. There were differences in nearly all forces, muscle efforts, postures, velocities and accelerations across keyboard, mouse and idle activities. Keyboard activities showed a 50% increase in the median right trapezius muscle effort when compared to mouse activities. Median shoulder rotation changed from 25 degrees internal rotation during keyboard use to 15 degrees external rotation during mouse use. Only keyboard use was associated with median ulnar deviations greater than 5 degrees. Idle activities led to the greatest variability observed in all muscle efforts and postures measured. In future studies, measurements of computer activities could be used to provide information on the physical exposures experienced during computer use. Practitioner Summary: Computer users may develop musculoskeletal disorders due to their force, muscle effort, posture and wrist velocity and acceleration exposures during computer use. We report that many physical exposures are different across computer activities. This information may be used to estimate physical exposures based on patterns of computer activities over time. © 2012 Copyright Taylor and Francis Group, LLC.
TL;DR: A real-time dynamical analysis method that was developed to detect unexpected perturbations in team communication is described and is demonstrated on perturbed communication from a three-person uninhabited air vehicle command-and-control team.
Abstract: Dynamical systems methods characterise patterns of change over time. Typically, such methods are applied only after data collection is complete. However, brief disturbances – perturbations – can occur as a process unfolds and can result in undesirable outcomes if not acted on. The application of dynamics in real time would be useful for detecting these sudden changes. Real-time analysis was accomplished by updating dynamical estimates simultaneously across different window sizes. We calculated the largest Lyapunov exponent, a measure of dynamical stability, to detect a perturbation to team communication in a simulated uninhabited air vehicle (UAV) reconnaissance mission. The perturbation consisted of information demands from a confederate that occurred unexpectedly during performance of a UAV mission. We demonstrate the use of real-time methods in detecting that perturbation as it occurred. In application, this technique would have enabled real-time intervention. Extensions of the real-time dynamical meth...