Sound localisation ability of soldiers wearing infantry ACH and PASGT helmets

Helmets provide soldiers with ballistic and fragmentation protection but impair auditory spatial processing. Missed auditory information can be fatal for a soldier; therefore, helmet design requires compromise between protection and optimal acoustics. Twelve soldiers localised two sound signals presented from six azimuth angles and three levels of elevation presented at two intensity levels and with three background noises. Each participant completed the task while wearing no helmet and with two U.S. Army infantry helmets – the Personnel Armor System for Ground Troops (PASGT) helmet and the Advanced Combat Helmet (ACH). Results showed a significant effect of helmet type on the size of both azimuth and elevation error. The effects of level, background noise, azimuth and elevation were found to be significant. There was no effect of sound signal type. As hypothesised, localisation accuracy was greatest when soldiers did not wear helmet, followed by the ACH. Performance was worst with the PASGT helmet.     

Shock absorption performance of a motorbike helmet with honeycomb reinforced liner

The enhancement of the energy absorption properties of motorbike helmets could significantly improve the safety of riders. This study reports a novel concept of helmet design, which consists in the use of aluminium honeycomb as reinforcement material of the helmet liner. A modified version of a commercial helmet is presented, in which aluminium honeycombs are used in the energy absorbing liner. The ECE 22.05 standard tests were performed on both the prototype helmets and their commercial counterparts (presenting same dimensions, geometry, material properties and weight), and the dynamic responses were compared. The results showed that the prototype helmets provided better protection to the head from impacts against the kerbstone anvil. More limited improvements were also observed in some of the impacts on flat anvil, although other results indicated to some extent the limitations of the strategy adopted in our research.     

基于智能视频图像分析的安全帽识别

为解决石油行业工作现场人员不佩戴安全帽的情况,避免因违规操作或违反规定,造成不必要的伤亡,提出一套基于施工现场安防监控系统的智能安全帽检测系统。设计一套综合利用安全帽的颜色、轮廓,以及多层神经网络分类建立的统计模型,对是否佩戴安全帽进行检测。结合实例,验证了算法的有效性和系统的可行性。实例结果表明,该系统能很好检测出现场没佩戴安全帽的人员,一定程度上杜绝了安全隐患,减少了事故的发生。     

Publication bias and time-trend bias in meta-analysis of bicycle helmet efficacy: a re-analysis of Attewell, Glase and McFadden, 2001

This paper shows that the meta-analysis of bicycle helmet efficacy reported by Attewell, Glase, and McFadden (Accident Analysis and Prevention 2001, 345–352) was influenced by publication bias and time-trend bias that was not controlled for. As a result, the analysis reported inflated estimates of the effects of bicycle helmets. This paper presents a re-analysis of the study. The re-analysis included: (1) detecting and adjusting for publication bias by means of the trim-and-fill method; (2) ensuring the inclusion of all published studies by means of continuity corrections of estimates of effect rely on zero counts; (3) detecting and trying to account for a time-trend bias in estimates of the effects of bicycle helmets; (4) updating the study by including recently published studies evaluating the effects of bicycle helmets. The re-analysis shows smaller safety benefits associated with the use of bicycle helmets than the original study.     

Drivers overtaking bicyclists: objective data on the effects of riding position, helmet use, vehicle type and apparent gender

A naturalistic experiment used an instrumented bicycle to gather proximity data from overtaking motorists. The relationship between rider position and overtaking proximity was the opposite to that generally believed, such that the further the rider was from the edge of the road, the closer vehicles passed. Additionally, wearing a bicycle helmet led to traffic getting significantly closer when overtaking. Professional drivers of large vehicles were particularly likely to leave narrow safety margins. Finally, when the (male) experimenter wore a long wig, so that he appeared female from behind, drivers left more space when passing. Overall, the results demonstrate that motorists exhibit behavioural sensitivity to aspects of a bicyclist's appearance during an encounter. In the light of previous research on drivers' attitudes to bicyclists, we suggest drivers approaching a bicyclist use physical appearance to judge the specific likelihood of the rider behaving predictably and alter their overtaking accordingly. However, the extent to which a bicyclist's moment-to-moment behaviour can be inferred from their appearance is questionable, and so the tendency for drivers to alter their passing proximity based on this appearance probably has implications for accident probability.     

Observational study of compliance with Queensland bicycle helmet laws

Mandatory bicycle helmet laws have been found to increase helmet wearing rates in Australia and internationally. However, much of the research on factors influencing compliance with the Australian helmet laws is dated or focuses on commuters and city areas only. To address this gap, video recordings of bicycle riders were undertaken at 17 sites across Queensland, Australia, representing a mixture of on- and off-road locations, speed limits and regions. Helmet status was able to be determined for 98% of riders observed. The level of compliance with the laws was very high, with 98.3% of the more than 27,000 riders observed wearing helmets. Riders riding on roads were less compliant than those riding on bicycle paths, but no significant differences were observed between the school-holiday and school-term periods. Among the on-road riders, boys were less compliant than girls and overall children were less compliant than adults. Higher compliance levels were found for group riders, road bike riders, lycra-clad riders, during morning hours, and on 50 km/h or lower speed limit roads. While the overall level of compliance was very high, certain subgroups were identified as a possible focus for interventions to further improve the compliance level, for example children (particularly boys) riding mountain bikes away from groups during the afternoon hours on 60 km/h roads.     

施工现场安全帽佩戴情况监控技术研究

针对施工工地需要统计和监控工人佩戴安全帽情况,提出一种基于计算机视觉的施工现场安全帽佩戴情况监控方法。首先用背景差法从获得的视频图像中提取出前景,并对其进行二值化将运动目标分割出来;然后再根据运动目标的特征通过尺度滤波等方法区分其是否为代表人的运动目标,对代表人的运动目标进行跟踪和标记;最后,在路面中间处设置两条检测线,当代表人的运动目标到达两条检测线中间时,通过检测其1/3部分中的像素点色度值分布情况,判断该人是否佩戴安全帽及安全帽的颜色。经实验结果表明,该方法能满足准确高效的要求。     

Modelling of the effectiveness of bicycle helmets under impact

A new approach to impact optimal design in bicycle helmets is presented. In this approach, the optimal design problem involving the comfort foam effect, global deformation of shell and local indentation is formulated on the basis of a mass–spring–damper–gap model. The impact model, the formulation for the impact response, the damping effect, and the effects of the physical gap, and the yield stress are described in detail. The predictions have shown good agreement with the experimental measurements.     

School regulations governing bicycle helmet use and head injuries among Japanese junior high school students

We examined the effectiveness of school regulations concerning bicycle helmet use in reducing head injuries among student bicycle commuters to junior high schools in the Japanese prefecture of Saitama. This was done by comparing the rates of head injuries and the ratios of head injuries to non-head injuries between junior high schools with and without school regulations concerning helmet use. Bicycle injury data were derived from school insurance records. Information relating to numbers of bicycle commuters and demographics was collected for each school. We identified that the head injury rate was significantly higher in schools that had no regulations governing the use of bicycle helmets (rate ratio 2.97, 95% confidence interval (CI) 1.03-8.56; odds ratio 2.46, 95% CI 0.80-7.60). The observed trend was more prominent in male students than in female students. The actual rate of bicycle injuries did not significantly differ between the schools with and without regulations concerning helmet use. This suggests that students at schools with regulations were no more cautious in riding their bicycles than their counterparts in schools with no regulations, and that there was no significant difference in the traffic environments surrounding each school. Thus implicating that the observed difference in the head injury rate was most accounted for by the presence of school regulations governing helmet use.