Impact of police body armour and equipment on mobility

Body armour is used widely by law enforcement and other agencies but has received mixed reviews. This study examined the influence of stab resistant body armour (SRBA) and mandated accessories on physiological responses to, and the performance of, simulated mobility tasks. Fifty-two males (37 ± 9.2 yr, 180.7 ± 6.1 cm, 90.2 ± 11.6 kg, VO_2max 50 ± 8.5 ml kg⁻¹ min⁻¹, BMI 27.6 ± 3.1, mean ± SD) completed a running VO_2max test and task familiarisation. Two experimental sessions were completed (≥4 days in between) in a randomised counterbalanced order, one while wearing SRBA and appointments (loaded) and one without additional load (unloaded). During each session participants performed five mobility tasks: a balance task, an acceleration task that simulated exiting a vehicle, chin-ups, a grappling task, and a manoeuvrability task. A 5-min treadmill run (zero-incline at 13 km·h⁻¹, running start) was then completed. One min after the run the five mobility tasks were repeated.     

Measuring the risk of sustaining injury in sport a novel approach to aid the re-design of personal protective equipment

Despite the possibilities offered by new approaches in design and advances in materials and manufacturing methods, few items of Personal Protective Equipment (PPE) used in sport have seen significant change for many decades. A major reason for this is the tradition and conservative attitudes associated with many sports, although the absence of appropriate tools and techniques to assist the design and development process has also played a large part. The aim of this study was to develop the first stage of a method of identifying specific regions of the human anatomy that are at the greatest risk of sustaining injury during participation in sports in which the player is subjected to multiple ballistic impacts. It is proposed that the findings could be used to confirm future designs of sports PPE. Previous studies have identified the amount and the location of the protection provided by current commercially available products but, until now, no evidence has been reported to determine what protection is required based on an understanding of the likely impact and the anatomy of the athlete.     

Component contribution of personal protective equipment to the alleviation of physiological strain in firefighters during work and recovery

The purpose of this study was to investigate the components contributions of personal protective equipment on physiological strain in firefighters during exercise and recovery. Eight firefighters participated in trials in which various combinations of personal protective equipment components weighing from 1.3 to 15.1 kg were worn. The results showed that rectal temperature, changes in rectal temperature, mean skin temperature, heart rate, oxygen consumption and blood lactate concentration were smaller in conditions without boots (no-boots) than in other conditions with no helmet, gloves or self-contained breathing apparatus (P < 0.05). Increases in rectal temperature per unit mass of personal protective equipment were approximately twice as small in no-boots condition as the other conditions. These results suggest that the reduction of the boots' mass might be more efficient to alleviate heat strain of firefighters wearing personal protective equipment, rather than the reduction of the mass of self-contained breathing apparatus, helmet or gloves.     

Information processing capacity while wearing personal protective eyewear

It is difficult to overemphasize the function vision plays in information processing, specifically in maintaining postural control. Vision appears to be an immediate, effortless event; suggesting that eyes need only to be open to employ the visual information provided by the environment. This study is focused on investigating the effect of Occupational Safety and Health Administration regulated personal protective eyewear (29 CFR 1910.133) on physiological and cognitive factors associated with information processing capabilities. Twenty-one college students between the ages of 19 and 25 years were randomly tested in each of three eyewear conditions (control, new and artificially aged) on an inclined and horizontal support surface for auditory and visual stimulus reaction time. Data collection trials consisted of 50 randomly selected (25 auditory, 25 visual) stimuli over a 10-min surface-eyewear condition trial. Auditory stimulus reaction time was significantly affected by the surface by eyewear interaction (F_2,40 = 7.4; p < 0.05). Similarly, analysis revealed a significant surface by eyewear interaction in reaction time following the visual stimulus (F_2,40 = 21.7; p < 0.05). The current findings do not trivialize the importance of personal protective eyewear usage in an occupational setting; rather, they suggest the value of future research focused on the effect that personal protective eyewear has on the physiological, cognitive and biomechanical contributions to postural control. These findings suggest that while personal protective eyewear may serve to protect an individual from eye injury, an individual's use of such personal protective eyewear may have deleterious effects on sensory information associated with information processing and postural control.     

Comparison of three internationally certified firefighter protective ensembles: Physiological responses,mobility, and comfort

BackgroundFire protective ensembles (FPEs) are essential to safely perform firefighting job tasks; however, they are often burdensome to the workers. The aim of this study was to compare three internationally certified fire protective ensembles from the European Union (EU), South Korea (SK), and United States (US) on physiological responses, mobility, and comfort.MethodsTen male professional firefighters performed a battery of exercises in the laboratory following the ASTM F3031-17 standard to evaluate mobility, occupation-specific performance, and physiological responses (body weight, heart rate (HR), core temperature (T_c), breathing rate (BR), and rating of perceived exertion (RPE)) to 20 min of treadmill walking (3.2 mph, 5% incline). All participants carried out the evaluation wearing each FPE in a random order. Mixed effects models examined time (pre-vs. post-) by ensemble (EU, SK, US) interactions for all physiological variables and compared comfort, performance, and subjective variables across ensembles.ResultsNo interaction effects were observed for body weight, HR, T_c, BR, or RPE (p = 0.890, p = 0.994, p = 0.897, p = 0.435, and p = 0.221; respectively). SK had greater trunk flexion than EU (78.4° vs. 74.6°, p = 0.026) and US had lower standing reach than EU (105.5 cm vs. 115.4 cm, p = 0.004). Agility circuit time was lower in US (9.3 s) compared to EU (9.8 s) or SK (9.9 s) (p = 0.051 and p = 0.019, respectively).ConclusionsThe findings suggest that physiological burden remained largely unchanged across the international FPEs. However, mobility, performance, and comfort may be significantly influenced across types. International stakeholders and end users should consider design implications when choosing fire protective ensembles.     

Effects of chemical protective equipment on team process performance in small unit rescue operations

In the event of a nuclear, biological, or chemical terrorist attack against civilians, both military and civilian emergency response teams must be able to respond and operate efficiently while wearing protective equipment. Chemical protective equipment protects the user by providing a barrier between the individual and hazardous environment. Unfortunately, the same equipment that is designed to support the user can potentially cause heat stress, reduced task efficiency, and reduced range-of-motion. Targeted Acceptable Responses to Generated Events of Tasks (TARGETS), an event-based team performance measurement methodology was used to investigate the effects of Mission Oriented Protective Posture (MOPP) on the behavioral processes underlying team performance during simulated rescue tasks. In addition, this study determined which team processes were related to team performance outcomes. Results of six primary analyses indicated that team process performance was not degraded by MOPP 4 on any rescue task and that the team processes critical for successful task performance are task-dependent. This article discusses the implications of these results with respect to the study design and the limitations of using an event-based team performance measurement methodology.     

Metabolic demands of law enforcement personal protective equipment during exercise tasks

Many occupations require the use of personal protective equipment (PPE) but the added metabolic demands are unknown for certain professions. The purpose of this study was to quantify metabolic and perceptual differences between activity with and without the PPE ensemble required for police officers. Twelve participants were asked to complete experimental and control exercise sessions consisting of three modes of exercise (walking, jogging and stepping). A significant main effect (p < 0.01) for gear was found for heart rate (beats per minute) and VO₂ (L/min) between conditions. Dependent t-tests revealed significant differences for perceived effort, discomfort and session rating of perceived exertion between trials. Medium to large effect sizes for all variables with significant main effects between modes (p < 0.01, η² = 0.51–0.96, 1–β = 0.98–1.0, d = 0.42–2.7) were observed. These findings help to increase awareness of how PPE affects metabolic demands and perception of discomfort during exercise.     

The effect of firefighter personal protective equipment on static and dynamic balance

Abstract

Firefighters work in unpredictable conditions, necessitating the use of personal protective equipment (PPE). However, the additional weight from the PPE and self-contained breathing apparatus (SCBA) alters their centre of mass (COM), restricts movement and limits vision (face mask) contributing to a firefighters’ challenge of maintaining balance. Thus, the purpose of this study was to quantify the effects of firefighter PPE on static and dynamic balance. Participants performed two sets of three functional balance tests: (1) Static Single Leg (SSL); (2) Dynamic Single Leg (DSL); (3) Limits of Stability (LOS). The balance tests were performed under one control and three randomised PPE conditions: (1) athletic clothing; (2) turnouts; (3) turnouts?+?SCBA; (4) turnouts?+?SCBA?+?face mask. Our study found turnouts?+?SCBA both with and without the face mask negatively affected dynamic balance. These findings identify factors in fall-related injuries and strategies to reduce occupational risk.

Practitioner summary: Slips, trips and falls are the most common cause of injury in firefighters. Our study investigated the effects of firefighter personal protective equipment (PPE) on static and dynamic balance utilising a computerised balance instrument. We found that turnouts with a self-contained breathing apparatus (SCBA) with or without face mask negatively affected balance.     

Effect of personal protective eyewear on postural stability

Vision is a significant factor in postural stability; this study is the first to report on the effect of OSHA regulated personal protective eyewear on physiological factors associated with postural stability. Twenty college students between the ages of 19 and 25 were randomly tested in each of three eyewear conditions (control, new, and artificially aged) using a NeuroCom^® Balance Master System and the mCTSIB protocol. Subjects were pre-tested with no eyewear (control) on each day followed by a 5-min assembly task with random eyewear assignment. Subjects were then post-tested following the same protocol while wearing the eyewear. Data were evaluated using a two (pre/post)?×?three (eyewear) repeated measures analysis of variance (ANOVA). There was a significant main effect for both the eyes open/firm flat surface, and eyes open/foam flat surface conditions (p???.05). These findings suggest that while personal protective eyewear may serve to protect an individual from eye injury, an individual's use of such personal protective eyewear may have deleterious effects on sensory input from the visual system and compensatory strategies to maintaining or regaining postural stability. Individuals who employ protective eyewear on a daily basis need to be aware of the effect of altered visual input resulting from eyewear on their postural stability, especially during sensory-challenging tasks, such as navigating ladders, scaffolding and elevated surfaces, typically found in construction environments.     

基于RapidIO总线的简约化小型导弹测试设备设计

为了保障导弹机动灵活的特点以及发射成功率,更加小型轻便简约的测试设备是提高部队平战时导弹保障效率的重要手段,基于RapidIO总线研制一种小型化测试设备,不再依赖机箱架构,仅依靠测试模块之间的堆叠连接,利用串行通信手段以及数据交换功能实现所有测试资源的数据交换及通信,可以大幅减小测试设备体积,解决了导弹测试设备携带不方便、转场困难的技术问题,同时对测试模块的选型,硬件架构、物理架构及设计指标等进行了分析说明,经过同某型PXI测试设备的对比测试,不仅完成了对某型导弹模拟器的测试功能,相比原PXI测试设备体积减小了95％以上,重量减轻了90％以上,功耗降低了60％以上,不仅可以适应更多的导弹测试场景,更可以大幅提高部队在日常训练维护以及战时精准保障的工作效率.     

Comparison of three individual tree crown detection methods

Three image processing methods for single tree crown detection in high spatial resolution aerial images are presented and compared using the same image material and reference data. The first method uses templates to find the tree crowns. The other two methods uses region growing. One of them is supported by fuzzy rules while the other uses an image produced by Brownian motion. All three methods detect around 80%, or more, of the visible sunlit trees in two pine Pinus Sylvestris L.) and two spruce stands Picea abies Karst.) in a boreal forest. For all methods, large tree crowns are easier to detect than small ones.     

Effects of the self-contained breathing apparatus and fire protective clothing on maximal oxygen uptake

To examine the effects of firefighting personal protective ensemble (PPE) and self-contained breathing apparatus (SCBA) on exercise performance, 12 males completed two randomly ordered, graded exercise treadmill tests (GXT_PPE and GXT_PT). Maximal oxygen consumption (VO_2max) during GXT_PPE was 17.3% lower than the GXT_PT in regular exercise clothing (43.0 ± 5.7 vs. 52.4 ± 8.5 ml/kg per min, respectively). The lower VO_2max during the PPE condition was significantly related (r = 0.81, p < 0.05) to attenuated peak ventilation (142.8 ± 18.0 vs. 167.1 ± 15.6 l/min), which was attributed to a significant reduction in tidal volume (2.6 ± 10.4 vs. 3.2 ± 0.4 l). Breathing frequency at peak exercise was unchanged (55 ± 7 vs. 53 ± 7 breaths/min). The results of this investigation demonstrate that PPE and the SCBA have a negative impact on VO_2max. These factors must be considered when evaluating aerobic demands of fire suppression work and the fitness levels of firefighters.     

Comparison and combination of iris matchers for reliable personal authentication

The personal identification approaches using iris images are receiving increasing attention in the biometrics literature. Several methods have been presented in the literature and those based on the phase encoding of texture information are suggested to be the most promising. However, there has not been any attempt to combine these approaches to achieve further improvement in the performance. This paper presents a comparative study of the performance from the iris authentication using Log-Gabor, Haar wavelet, DCT and FFT based features. Our experimental results suggest that the performance from the Haar wavelet and Log-Gabor filter based phase encoding is the most promising among all the four approaches considered in this work. Therefore, the combination of these two matchers is most promising, both in terms of performance and the computational complexity. Our experimental results from the all 411 users (CASIA v3) and 224 users (IITD v1) database illustrate significant improvement in the performance which is not possible with either of these approaches individually.     

Predicting the adoption of mobile financial services: The impacts of perceived mobility and personal habit

Mobile financial services (MFS) have become a critical issue in the financial sectors. An expanding application of mobile commerce, MFS play an important role in managing customer relationships. Thus, we proposed a model that incorporates three external variables—perceived enjoyment, perceived mobility, and personal habit—into the technology acceptance model (TAM) to assess the antecedents that influence continued usage intention in MFS. In addition, we examined the moderating effect of gender on customer relationships. Structural equation modeling was used, and 368 MFS users were investigated. The findings revealed that perceived mobility, personal habit, perceived usefulness, and perceived ease of use are the major antecedents that influence continued usage intention in MFS. However, perceived enjoyment is not significantly associated with intention. Moreover, gender moderates the relationships between the variables in the proposed model. Perceived mobility affecting usage intention will be stronger for men than for women, whereas personal habit affecting usage intention will be stronger for women than for men.     

武器装备敏感性分析方法综述

武器装备敏感性分析是武器装备发展论证的重要内容,其方法的选用对结论的合理性,分析的可行性极为重要,为此需对已有方法进行对比分析.阐述了敏感性分析方法的分类,给出了筛选方法、局部敏感性方法和全局敏感性方法的适用范围;研究了全局敏感性分析方法中回归分析法、傅立叶振幅敏感性检验法、响应曲面法,互信息指数法和Sobol指数法等的思想、原理,并对其优缺点进行详细的对比分析;提出由于Sobol指数法对效能评估模型的线性、单调性以及输入的分布特性没有专门要求,并且能分析单个输入的主效应、全效应及多个输入的交互效应对模型输出的影响,以及分析成组输入因素对输出的影响,因而相对其它方法而言更加适用于武器装备敏感性分析.     

基于1553B总线架构的测试设备设计与实现

随着1553B总线在航空系统和地面车辆系统中分布式从属设备连接方式的广泛应用,提高武器装备保障体系中的测试设备的设计灵活性、可靠性以及可确定性显得尤为重要;因此,提出了一种基于1553B总线架构思想的PXI总线测试设备的设计方法与实现方式,经过工程实际应用表明,能够满足装备的测试需求,具有良好的可扩展性、实时性和可靠性等特点,对武器装备测试领域的设备研制有一定的参考价值。     

电力无线单兵检测设备参数实时监测技术研究

针对传统电力无线单兵检测设备的实时估计能力低等问题,提出一种基于统计特征分析的电力无线单兵检测设备参数实时监测技术,通过对该设备参数进行实时监测,提高其性能监测和实时估计能力。采用无线传感器技术采集电力无线单兵检测设备参数实时数据,结合大数据统计特征分析方法对获得参数数据进行信息融合处理,并完成电力无线单兵检测设备参数实时统计,提取设备参数的谱特征量,通过时频分析和小波尺度分解方法,实现对电力无线单兵检测设备参数实时监测。实验结果表明,采用该方法监测电力无线单兵检测设备参数的实时估计能力高,稳定收敛性好,监测误差低。     

航天装备一体化试验模式创新构想探讨

太空领域战略博弈和竞争成为未来作战形式的研究热点,航天装备作为新质作战能力的重要组成部分,对未来太空资源的争夺和保护起着不可小觑的作用,而航天装备试验鉴定是检验航天装备作战能力的重要手段和方法;针对现行航天装备试验鉴定与航天装备发展要求之间存在不够匹配、研制周期偏长、试验效率低以及试验成本高等问题,借鉴美国航天装备一体化试验模式和特点,对比我国航天装备发展现状及存在的问题,运用"5W1H"的分析方法,构建了"面向需求,基于能力"的一体化试验框架模式,提出了航天装备一体化试验运行机制可行性建议,探索设计出适合我国航天装备的一体化试验流程,为下一步航天装备一体化试验模式的顶层设计、统筹规划、决策建议研究提供技术参考.     

Effect of base layer materials on physiological and perceptual responses to exercise in personal protective equipment

Ten men (non-firefighters) completed a 110 min walking/recovery protocol (three 20-min exercise bouts, with recovery periods of 10, 20, and 20 min following successive bouts) in a thermoneutral laboratory while wearing firefighting personal protective equipment over one of four base layers: cotton, modacrylic, wool, and phase change material. There were no significant differences in changes in heart rate, core temperature, rating of perceived exertion, thermal discomfort, and thermal strain among base layers. Sticking to skin, coolness/hotness, and clothing humidity sensation were more favorable (p < 0.05) for wool compared with cotton; no significant differences were identified for the other 7 clothing sensations assessed. Separate materials performance testing of the individual base layers and firefighting ensembles (base layer + turnout gear) indicated differences in thermal protective performance and total heat loss among the base layers and among ensembles; however, differences in heat dissipation did not correspond with physiological responses during exercise or recovery.     

虚拟仪表技术在空空导弹测试设备中的应用

介绍了虚拟仪器的产生、发展及基本内容。针对空空导弹测试的重要性问题,设计了一种基于虚拟仪表技术的测试系统。该系统以虚拟仪表为核心,采用GL Studio软件开发工具,有效地提高了系统的通用性、可靠性。