290 research outputs found
Subjective skeletal discomfort measured using a comfort questionnaire following a load carriage exercise
Objective: Limited research has been conducted into the effect of load carriage on discomfort and injuries. This study aimed to determine the skeletal discomfort for part-time soldiers who completed a 1-hour field march carrying 24 kg.
Methods: A postmarch comfort questionnaire was completed by 127 participants, with exercise withdrawals and postmarch injuries also recorded.
Results: The foot was subjectively rated as the most uncomfortable skeletal region. Females reported hip discomfort to be significantly greater than males. The military experience of participants had no difference on the mean perceived comfort ratings of any of the measured regions. Finally, only one participant withdrew from the exercise, with no participants reporting a load carriage injury in the 2 to 3 days proceeding the exercise Conclusions: This study concludes that although a 1-hour period of load carriage causes noteworthy discomfort it is not sufficient to result in noncompletion of a military exercise or cause injury
Smart driving aids and their effects on driving performance and driver distraction
In-vehicle information systems have been shown to increase driver workload and cause distraction; both of which are causal factors for accidents. This simulator study evaluates the impact that two designs for a smart driving aid, and scenario complexity have on workload, distraction and driving performance. Results showed that real-time delivery of smart driving information did not increase driver workload or adversely effect driver distraction, while having the effect of decreasing mean driving speed in both the simple and complex driving scenarios. Subjective workload was shown to increase with task difficulty, as well as revealing important differences between the two interface designs
Exponential Stabilisation of Continuous-time Periodic Stochastic Systems by Feedback Control Based on Periodic Discrete-time Observations
Since Mao in 2013 discretised the system observations for stabilisation problem of hybrid SDEs (stochastic differential equations with Markovian switching) by feedback control, the study of this topic using a constant observation frequency has been further developed. However, time-varying observation frequencies have not been considered. Particularly, an observational more efficient way is to consider the time-varying property of the system and observe a periodic SDE system at the periodic time-varying frequencies. This study investigates how to stabilise a periodic hybrid SDE by a periodic feedback control, based on periodic discrete-time observations. This study provides sufficient conditions under which the controlled system can achieve pth moment exponential stability for p > 1 and almost sure exponential stability. Lyapunov's method and inequalities are main tools for derivation and analysis. The existence of observation interval sequences is verified and one way of its calculation is provided. Finally, an example is given for illustration. Their new techniques not only reduce observational cost by reducing observation frequency dramatically but also offer flexibility on system observation settings. This study allows readers to set observation frequencies according to their needs to some extent
Smart driving assistance systems : designing and evaluating ecological and conventional displays
In-vehicle information systems have been shown to increase driver workload and cause distraction;
both are causal factors for accidents. This simulator study evaluates the impact that two designs for
a smart driving aid and scenario complexity has on workload, distraction and driving performance.
Results showed that real-time delivery of smart driving information did not increase driver workload
or adversely affect driver distraction, while having the effect of decreasing mean driving speed
in both the simple and complex driving scenarios. Important differences were also highlighted
between conventional and ecologically designed smart driving interfaces with respect to subjective
workload and peripheral detection
Initial subjective load carriage injury data collected by interviews and questionnaires
This study aimed to identify the types, incidence, and causes of any potential load carriage injuries or discomfort as a result of a 2-hour, forced-speed, treadmill march carrying 20 kg. Subjective load carriage data were collected, through both interviews and questionnaires, from relatively inexperienced soldiers after a period of load carriage. Results from the study showed that the upper limb is very susceptible to short-term discomfort, whereas the lower limb is not. The shoulders were rated significantly more uncomfortable then any other region, and blisters were experienced by ∼60% of participants. Shoulder discomfort commences almost as soon as the load is added and increases steadily with time; however, foot discomfort increases more rapidly once the discomfort materializes. In conclusion, early development of shoulder pain or blisters may be a risk factor for severe pain or noncompletion of a period of prolonged load carriage
Ecological interface design for eco-driving
Eco-driving issues are of high priority at the moment. Research suggests that a change in driving style can reduce fuel consumption and emissions by around 15% in many cases. In response to this need, the UK Foot-LITE project developed an in-car feedback system to encourage safer and greener driving behaviours. In order
to balance positive behaviour change against the potential negative effects of distraction, an Ecological Interface Design approach was adopted. The current paper presents an overview of the humancentred
design process adopted in the Foot-LITE project, as well as a review of other similar systems on the market
The effect of military load carriage on ground reaction forces
Load carriage is an inevitable part of military life both during training and operations. Loads carried are frequently as high as 60% bodyweight, and this increases injury risk. In the military, load is carried in a backpack (also referred to as a Bergen) and webbing, these combined form a load carriage system (LCS). A substantial body of literature exists recording the physiological effects of load carriage; less is available regarding the biomechanics. Previous biomechanical studies have generally been restricted to loads of 20% and 40% of bodyweight, usually carried in the backpack alone. The effect of rifle carriage on gait has also received little or no attention in the published literature. This is despite military personnel almost always carrying a rifle during load carriage. In this study, 15 male participants completed 8 conditions: military boot, rifle, webbing 8 and 16 kg, backpack 16 kg and LCS 24, 32 and 40 kg. Results showed that load added in 8 kg increments elicited a proportional increase in vertical and anteroposterior ground reaction force (GRF) parameters. Rifle carriage significantly increased the impact peak and mediolateral impulse compared to the boot condition. These effects may be the result of changes to the vertical and horizontal position of the body's centre of mass, caused by the restriction of natural arm swing patterns. Increased GRFs, particularly in the vertical axis, have been positively linked to overuse injuries. Therefore, the biomechanical analysis of load carriage is important in aiding our understanding of injuries associated with military load carriage
Improving driver behaviour by design: a cognitive work analysis methodology
Within the European Community both the environmental and safety costs of road transport are unacceptably high. ‘Foot-LITE’ is a UK project which aims to encourage drivers to adopt ‘greener’ and safer driving practices, with real-time and retrospective feedback being given both in-vehicle and off-line. This paper describes the early concept development of Foot-LITE, for which a Cognitive Work Analysis (CWA) was conducted. In this paper, we present the results of the first phase of CWA – the Work Domain Analysis, as well as some concept interface designs based on the WDA to illustrate its application. In summary, the CWA establishes a common framework for the project, and will ultimately contribute to the design of the in-vehicle interfac
Safe driving in a green world : a review of driver performance benchmarks and technologies to support ‘smart’ driving
Road transport is a significant source of both safety and environmental concerns. With climate change and fuel prices increasingly prominent on social and political agendas, many drivers are turning their thoughts to fuel efficient or ‘green’ (i.e., environmentally friendly) driving practices. Many vehicle manufacturers are satisfying this demand by offering green driving feedback or advice tools. However, there is a legitimate concern regarding the effects of such devices on road safety – both from the point of view of change in driving styles, as well as potential distraction caused by the in-vehicle feedback. In this paper, we appraise the benchmarks for safe and green driving, concluding that whilst they largely overlap, there are some specific circumstances in which the goals are in conflict. We go on to review current and emerging in-vehicle information systems which purport to affect safe and/or green driving, and discuss some fundamental ergonomics principles for the design of such devices. The results of the review are being used in the Foot-LITE project, aimed at developing a system to encourage ‘smart’ – that is safe and green – driving
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