基于可编辑VR实验平台的突发事件下跟随效应研究

建立了可编辑VR疏散动力学实验平台,并招募100名大学生开展地铁车厢内的虚拟实验,探究突发事件下的跟随效应。每次实验有一名实验人员和20名虚拟乘客(NPC)参与,共设置5个场景探究不同比例的运动NPC对参与者预动作行为和运动行为的影响。通过分析问卷、预动作时间、出门选择、运动距离等数据,发现在实验中存在跟随等待人群和跟随运动人群两种跟随效应,而人群的运动是更为强烈的信息,当等待和运动NPC占比从0%提升至50%,等待和运动参与者占比分别提高10%和60%。因此,在突发事件场景中,应及时对局部人群施加有效的同向引导,以提升整体疏散效率。     

城市道路驾驶人横向避险特性研究

为提高城市道路驾驶人横向避险能力,利用固定基座驾驶模拟器搭建5种典型城市道路危险交通场景,并借助眼动仪采集35名驾驶人的眼动数据和避险操作数据;分别统计并分析驾驶人的视线分布、感知-制动时间、持续制动时间、最大方向盘转角时间和车辆横向位置变化等参数。结果表明:5种场景下驾驶人水平视线基本上都处于中部偏右区域;除场景3外,驾驶人的感知-制动时间均值均在1 s内;在视线无遮挡场景,驾驶人主要通过制动进行避险,反之则以转向和制动相结合的方式进行避险。     

严重冲突场景下山区双车道公路货车跟驰风险预测

为预测严重冲突场景下山区双车道公路货车跟驰事故风险，基于视频轨迹数据、实测交通流数据、道路线形数据及交通事故数据，采用双变量冲突极值模型、轻量型梯度提升机，构建严重冲突场景下山区双车道公路货车跟驰事故风险实时预测(Truck Following Accident Risk Real-Time Prediction, TFARRP)模型，并利用耦合度模型分析变量耦合程度。研究显示：碰撞时间(Time to Collision)为5.418 s,后侵入时间(Post Encroachment Time)为0.512 s,这是严重冲突场景阈值；TFARRP模型准确率高达95.000%;平均车头时距(A_HD)、两车间距(T_CD)、货车平均速度(T_AS)、及货车横向偏移(T_LO)对TFARRP模型的重要度都超过了10%;当监测到A_HD<21.11 s、T_CD<35.00 m、T_AS<29.00 km/h或T_LO     

紧绷实验室安全弦

增强现实技术,是一种将真实世界信息和虚拟世界信息“无缝”集成的新技术,是把原本在现实世界中一定时间、空间范围内很难体验到的实体信息(视觉信息、声音等),通过电脑等科学技术,模拟仿真后再叠加,将虚拟的信息应用到真实世界,被人类感官所感知,从而达到超越现实的感官体验。从2019年第一期开始,本刊以增强现实(AR)技术为手段,以防空防灾为主线,开设媒体融合专栏。亲爱的读者们,您可以利用智能手机、平板电脑等移动智能终端,直接扫描右面的二维码,安装并打开APP,就可以学习防空防灾知识,体验真实的救灾场景啦!     

驾驶员接管自动驾驶车辆的眼动特性和行为分析

为探究接管自动驾驶车辆期间驾驶员的视觉特性,分析眼动与接管反应操控行为的关系,开展驾驶模拟试验收集驾驶行为及眼动数据。运用统计学方法,分析驾驶员感知不同接管场景的视觉特性,探究接管请求(TOR)前后眼动指标的变化规律;并基于视觉分配和瞳孔变化特性分析驾驶行为,揭示眼动特性与接管反应及驾驶操纵策略的内在联系。结果表明:TOR前,相较于静态场景,驾驶员感知动态场景诱发元素扫视更频繁且平均注视时间更短;此时驾驶员的视觉分配特性与其接管反应行为存在显著相关性。TOR后,驾驶员的注视时间增加,眨眼频率降低,瞳孔直径扩张,眼跳幅度增大;不同场景下驾驶员的瞳孔差异表明其应对动态场景时具备更好的警戒水平和更平稳的操纵策略。     

开口钢管内甲烷爆炸火焰厚度和压力发展特征

通过搭建长为20m、截面为0.08m×0.08m的非绝热开口钢管,研究了甲烷与空气预混气体发生爆炸后的火焰和压力发展特征。实验结果表明:火焰信号最强的时刻对应于火焰前锋反应区内某时刻,而火焰信号起始上升时刻与火焰前锋预热区起始时刻接近,应选择某点火焰信号起始上升时刻作为该点的火焰到达时间。随着远离点火源距离的增加,火焰厚度呈现先变薄后变厚的变化趋势,最大超压呈现先减小、后增大、再减小的趋势,火焰传播速度则呈先增大后减小的变化过程。非绝热开口钢管的实验条件对爆炸超压和火焰传播速度的影响较大。研究成果可为甲烷爆炸致灾机制及防控的研究提供参考。     

安全标志排列顺序的视觉注意特征研究*

为研究安全标志位置设置的视觉注意特征,选取国标中4种安全标志（警告、禁止、指令、提示）进行排列组合,利用Eyelink Ⅱ记录20名被试的平均注视时间和首次注视时间,并采用统计学及视觉注意理论进行分析。研究结果表明:从位置角度分析,无论横向还是纵向排列,位置Ⅱ的首次注视时间相对较短,且当禁止标志位于位置Ⅱ时,首次注视时间平均值相对较小;从平均注视时间角度分析,禁止标志位于位置Ⅱ时,平均注视时间相对较长;通过横纵位置Ⅱ的对比可知,禁止标志位于位置Ⅱ时,排列方式对平均注视时间及首次注视时间无显著影响（p>0.05）;横向中偏左的位置及纵向中偏上的位置具有较好的识别性,而禁止标志位于位置Ⅱ时,显著性更高且横向与纵向无差异,国标的顺序设置更能增强安全标志的显著性。     

智能疏散指示标志诱导系统优化设计与人流控制研究

为改善疏散指示标志在紧急情况下的疏散引导效果,基于逃生者的信息感知等因素,开发智能疏散指示系统的疏散路线优化算法。将安全疏散的基本原则、智能疏散指示系统的设置位置、建筑空间结构及典型火灾场景相结合,综合考虑路径长度、出口宽度、人员密度以及疏散人群分布等因素,针对特定场景,改进智能疏散指示标志。结果表明:改进后的指示标志能指引人员迅速找到疏散路线,有效地缩短疏散时间;将指示标志的控制作用纳入人群分布预测模型,可得到更接近真实情形的疏散人群分布预测模型。     

深井受限空间内作业人员的眼动特征研究

为探索能反映深井受限空间对作业者影响程度的眼动指标,为井下行为安全管理提供依据,将20名眼动指标相近的成员随机分为A,B两组,分别在普通环境中和高温深井环境中开展实验,以文献摘要为刺激材料,运用Tobii X2-30眼动仪进行眼动测量,运用单因素多元方差分析及多重比较法分析眼动数据。发现注视点总数、总注视时间、眼跳次数和总眼跳时间指标的差异有显著性,B组值大于A组;注视点平均注视时间、平均眨眼时间、平均瞳孔直径和总眼跳时间占比等指标无显著差异;两组被试的注视轨迹变化显著,因此 对井下人员的生理信息采集应当注重5个关键的眼动指标。     

基于蒙特卡罗的平行跑道进近碰撞风险分析

为在新的导航方式下对具有随机复杂特性的平行跑道进近碰撞风险进行评估，构建了一种面向多个对象集的进近碰撞风险仿真模拟模型。首先根据实际航迹数据获取基于性能导航(Performance Based Navigation, PBN)的实际导航性能(Actual Navigation Performance, ANP)分布规律特征，基于ANP分布函数可得进近轨迹偏离概率；随后构建了仿真轨迹模拟模型，并将国际民航组织(International Civil Aviation Organization, ICAO)的经典失误进近场景应用其中；最后针对不同非侵入区(No Transgression Zone, NTZ)宽度、不同失误场景进行仿真试验。结果表明：此模型可以快速且合理地对进近场景进行仿真模拟；在安全目标水平下的PBN导航进近可缩小NTZ宽度，从而减轻管制员工作量，提高进近运行效率。     

基于VR技术的大型储罐火灾爆炸仿真软件设计

为了研究大型储罐事故后果的严重性，针对大型储罐火灾爆炸试验难以实施的情况，以虚拟现实技术为研究手段，重现大型储罐火灾和爆炸事故过程；通过对储罐火灾和爆炸事故进行理论分析，优选出大型储罐火灾爆炸事故后果数学模型；基于某商业原油储备库布置，利用3Ds Max软件对库区进行建模，结合Qt界面编写技术和OSG粒子效果技术进行交互式设计，划分火灾和爆炸2大仿真模块，设计各模块下属基本功能，形成1套基于真实场景的大型储罐火灾爆炸事故后果三维仿真模拟软件。研究结果表明:基于VR技术的大型储罐火灾爆炸仿真软件具有较强的沉浸感和交互性等特点，能够实时仿真大型储罐火灾爆炸事故动态演变过程，降低大型储罐火灾爆炸试验成本，同时为制定事故应急预案和应急处置措施提供科学参考。     

Using virtual reality technology in organizational behavior research

Conventional research methodologies that use written vignettes to present stimuli have been criticized as lacking in realism. We propose the use of highly immersive virtual reality (VR) technology to overcome limitations of written vignettes and other traditional methodologies. We also illustrate how VR technology can be effectively used to investigate various topics in organizational behavior and industrial/organizational psychology. © 1997 John Wiley & Sons, Ltd.     

Research on 3D dynamic visualization simulation system of toxic gas diffusion based on virtual reality technology

A three-dimensional (3D) model of toxic gas diffusion was advanced based on Monte Carlo method with the presupposition that toxic gas diffusion process can be considered as random walk process of a large number of toxic gas particles. Compared to other existing models, this model includes analysis of both movement and non-movement attributes of toxic gas particles, and can well meet the need of dynamic simulation. Then, a 3D gas diffusion visualization scene management subsystem, including leak hazard source (tank), leak background (ground and sky) and surroundings near the leak area, was developed based on virtual reality (VR) technology. In this system, diffusion scene can be designed in accordance with the reality, which embodies the reunification between VR technology and engineering application. Finally, according to OpenGL particle system theory, by using Delphi and OpenGL as main programming tools, the diffusion simulation subsystem of toxic gas diffusion process and real-time concentration prediction and consequence simulation subsystem was completed. Application shows that by using VR technology in the accident consequence simulation, the whole system is of real-time, lifelike and visual characteristics, which not only embodies the great engineering value of virtual reality technology in the field of safety engineering, but also provides references for accident impact prediction, assessment and emergency plan.     

Workstations for people with disabilities: an example of a virtual reality approach

This article describes a method of adapting workstations for workers with motion disability using computer simulation and virtual reality (VR) techniques. A workstation for grinding spring faces was used as an example. It was adjusted for two people with a disabled right upper extremity. The study had two stages. In the first, a computer human model with a visualization of maximal arm reach and preferred workspace was used to develop a preliminary modification of a virtual workstation. In the second stage, an immersive VR environment was used to assess the virtual workstation and to add further modifications. All modifications were assessed by measuring the efficiency of work and the number of movements involved. The results of the study showed that a computer simulation could be used to determine whether a worker with a disability could access all important areas of a workstation and to propose necessary modifications.     

Child pedestrian behaviors: Influence of peer social norms and correspondence between self-reports and crossing behaviors

Objective: The aims of this study were to determine if children's perception of peers' behavioral norms for crossing streets relates to their personal norms for doing so and if children's self-reports about crossing relates to their actual crossing in a virtual traffic situation. Method: Children (8–10 years, N = 86) completed questionnaires about peer's norms and their personal norms about crossing streets, and also reported on their recent crossing behaviors. These self-reports about crossing were then related to children's actual crossing behaviors measured using a fully immersive virtual reality (VR) system. Results: Children's perception of peers' behavioral norms for crossing related to their personal norms for doing so, and their norms related to their reports of how they have crossed in the past few weeks. When crossing virtual streets, children with higher scores on self-reports about risky crossing behaviors selected smaller (riskier) inter-vehicle gap sizes to cross into, showed less start delay (less time appraising traffic before starting), and experienced more hits. Conclusion and practical applications: Children's perception of peers' behavioral norms for crossing are relevant to their crossing behaviors and may be one way that peers elevate children's risk of pedestrian injury. Children's self-reports about crossing risk may be useful for identifying at-risk youth and strategically targeting interventions to these children.     

基于Vega的灭火救援视景仿真研究

Vega是目前流行的虚拟现实应用程序开发环境,与Vega环境相关的应用程序还有三维建模工具Creator和人物仿真软件DI-GUY.在基于虚拟现实技术的灭火救援模拟训练系统中,救援场景的视景仿真是其重要组成部分.本文分析了基于Vega的软件平台开发灭火救援视景仿真系统的可行性,论述了在开发仿真系统过程中的一些关键技术,包括数据处理流程、三维建模、Vega软件的二次开发等.结论表明,利用Vega技术开发灭火救援视景仿真系统的方法是切实可行的.     

Studying freeway merging conflicts using virtual reality technology

Introduction: This research aims to investigate the perceptions and reactions of drivers regarding freeway merging situation, utilizing a new approach with the basis of a multilevel simulation platform which incorporates virtual reality (VR) technology. Methods: A VR driving environment integrated with traffic micro-simulation was developed to evaluate driving behaviors and the impact of merging decisions in terms of traffic conflicts. The driving experiments were conducted under a variety of circumstances, including varying traffic flows and the presence of ramp metering. The Surrogate Safety Assessment Model (SSAM) was utilized to extract the number of conflicts from the micro-simulation results. Results: The final results indicated that the probability of conflict has a positive correlation with traffic flow, while conflict frequency at freeway merges is affected by the presence of ramp metering due to its potentiality to enhance driver decisions and reduce the drivers’ pressure when they make maneuvers. Practical Applications: The findings reveal that the proposed VR simulation platform is a useful tool to improve the safety of freeway merging. It has the potential to enhance driver skills and can also be used in the study of human–machine interaction.     

Prediction of distance to maximum intensity of turbulence generated by grid plate obstacles in explosion-induced flows

The interaction of unburnt gas flow induced in an explosion with an obstacle results in the production of turbulence downstream of the obstacle and the acceleration of the flame when it reaches this turbulence. Currently, there are inadequate experimental measurements of these turbulent flows in gas explosions due to transient nature of explosion flows and the connected harsh conditions. Hence, majority of measurements of turbulent properties downstream of obstacles are done using steady-state flows rather than transient flows. Consequently, an empirical based correlation to predict distance to maximum intensity of turbulence downstream of an obstacle in an explosion-induced flow using the available steady state experiments was developed in this study. The correlation would serve as a prerequisite for determining an optimum spacing between obstacles thereby determining worst case gas explosions overpressure and flame speeds. Using a limited experimental work on systematic study of obstacle spacing, the correlation was validated against 13 different test conditions. A ratio of the optimum spacing from the experiment, x_exp to the predicted optimum spacing, x_pred for all the tests was between 2-4. This shows that a factor of three higher than the x_pred would be required to produce optimum obstacle spacing that will lead to maximum explosion severity. In planning the layout of new installations, it is appropriate to identify the relevant worst case obstacle separation in order to avoid it. In assessing the risk to existing installations and taking appropriate mitigation measures it is important to evaluate such risk on the basis of a clear understanding of the effects of separation distance and congestion. It is therefore suggested that the various new correlations obtained from this work be subjected to further rigorous validation from relevant experimental data prior to been applied as design tools.     

基于虚拟现实技术的喷射火事故三维动态仿真及应用

基于Shell模型的原理和计算方法,把喷射火焰视为近似倒立圆台形,构建了不同风向影响下的喷射火三维模型,运用虚拟现实技术和三维可视化技术对喷射火事故进行模拟与仿真。以Delphi和OpenGL/GLScene为开发工具,实现了喷射火三维模型的程序化与三维场景绘制,同时引入粒子特效系统,实现了喷射火焰燃烧的实时动态仿真,完成了喷射火三维动态可视化软件系统的开发。最后,利用该系统进行实例分析。应用表明:虚拟现实技术与事故后果模拟相结合,使整个系统实现实时性和形象性的统一,虚拟现实技术在化工行业具有广泛应用前景,也为事故后果预测评估提供科学依据。