Are you awake? Mobile phone use after lights out

Night-time mobile phone use has the potential to detract from sleep quality and continuity, resulting in tiredness and impaired psychological function. An on-line survey of the mobile phone habits of 397 adults (M age = 34.45, SD = 13.29) revealed that 75% used a mobile phone after lights out at least once a month, with 12.8% making calls at any time of night. More than 50% of participants reported being woken by the phone use of other people sharing their sleeping space. Using the phone after lights out and a general unwillingness to turn the phone off made a small but significant contribution to the level of tiredness. Tiredness made a significant contribution to DASS scores, with higher levels of tiredness being associated with more depression, anxiety and stress. Objective measures of sleep fragmentation and phone use along with diary recordings of participants’ evaluations of the affective value of each call or text, would be valuable in the exploration of the impact of night time phone use on tiredness and psychological function.     

Tiredness! a natural explanation to The Grand Rapid "DIP"

The present analysis deals with the presumed improved driving skill of car drivers with low blood alcohol concentrations (BACs) compared to the driving skill of sober drivers. Several roadside surveys indicate such a controversial possibility, which is illustrated graphically in "The Grand Rapid Study" (1964) as a relative accident risk curve for driving while intoxicated (DWI). A curve which shows a "DIP" below a baseline accident risk of one for sober drivers in the interval between BACs of 0.01 and 0.04 g/l. Since then, various attempts have been made to show this "DIP" in the otherwise "exponentially" raising curve to be an artificial distortion based on disproportionate demographic subgroups. It is, however, our thesis that the observations of "The Grand Rapid Study" and other roadside surveys are valid, because the presumed mono-causal traffic accident curve hides "tiredness" as an additional human risk factor. This makes the first part of the night-time relative accident risk curve for impaired drivers artificially augmented by "tired" drivers with insignificant amounts of alcohol in the blood and therefore incorrectly accused of accidents due to DWI. The accident risk curve for higher BACs raises similarly abrupt due to drivers impaired by a combined effect of alcohol and "tiredness". Moreover, to imply an accident risk of one for all sober drivers independent of the time of the day is debatable as an increased accident risk is present in the late night-time hours due to "tired" drivers. This increase in "tired" sober accident drivers suppresses the accident risk curve for DWI with BACs of 0.01-0.04 g/l below the fixed baseline of one for the background population.     

基于人机工程学单调作业的疲劳模型

基于人机工程学原理,建立了单调作业疲劳形成的人机工程学模型,并从人机工程学的角度分析单调作业疲劳的形成机理、原因、因素以及其数学模型。对预防单调作业的疲劳,保障机械加工的安全,以及人机界面设计具有积极的理论与现实意义。     

Road accidents caused by sleepy drivers: Update of a Norwegian survey

The current study tests, updates and expands a model of factors associated with sleepy driving, originally based on a 1997 survey of accident-involved Norwegian drivers (Sagberg, F., 1999. Road accidents caused by drivers falling asleep. Accident Analysis & Prevention 31, 639–649). The aim is to establish a robust model to inform measures to tackle sleepy driving. The original questions on (i) tiredness-related accidents and (ii) incidents of sleep behind the wheel in the last 12 months were again posed in 2003 and 2008, in independent surveys of Norwegian drivers involved in accidents reported to a large insurance company. According to those drivers at-fault for the accident, tiredness or sleepiness behind the wheel contributed to between 1.9 and 3.9 per cent of all types of accident reported to the insurance company across these years. Accident-involved drivers not at fault for the accident reported a reduction in the incidence of sleep behind the wheel for the preceding year, decreasing from 8.3 per cent in 1997 to 2.9 per cent in 2008. The reasons for this are not clear. According to logistic regression analysis of survey responses, the following factors were robustly associated with road accidents involving sleepy driving: driving off the road; good road conditions; longer distance driven since the start of the trip; and fewer years with a driving licence. The following factors are consistently associated with reports of sleep behind the wheel, whether or not it leads to an accident: being male; driving further per year; being younger; and having sleep-related health problems. Taken together these findings suggest that young, inexperienced male drivers who drive long distances may be a suitable target for road safety campaigns aimed at tackling sleepy driving.     

应用人机工程学研究轮椅的舒适性

这里简述人机工程学与轮椅舒适性的密切关系,以及轮椅舒适性设计的主要相关参数。     

The acceptable load while marching at a speed of 5km h-1 for young Chinese males

Ninety-three young Chinese men selected at random were involved in the load carrying experiments. They marched at 5 km h^?1 carrying loads of 0,15,20,25 and 31 kg for 7 h per day. At this speed the acceptable load to be carried was 20 kg. Under this load 95% of the men had heart rates below 120 btmin"’ while marching and energy metabolism was in balance. Nevertheless, 10-15% of the men were fatigued and felt tired.