Development and Use of a Sedimentation Risk Index for Unpaved Road‐Stream Crossings in the Choctawhatchee Watershed1

Abstract: Unpaved road‐stream crossings increase sediment yields in streams and alter channel morphology and stability. Before restoration and sedimentation reduction strategies can be implemented, a priority listing of unpaved road‐stream crossings must be created. The objectives of this study were to develop a sedimentation risk index (SRI) for unpaved road‐stream crossings and to prioritize 125 sites in the Choctawhatchee watershed (southeastern Alabama) using this model. Field surveys involved qualitative and quantitative observations of 73 metrics related to waterway conditions, crossing structures, road approaches, and roadside soil erosion. The road‐stream crossing risk analyses involved elimination of candidate metrics based on redundancy, skewness, lack of data, professional judgment, lack of nonzero values, unbalanced box plots, and limited ranges of values. A final selection of 12 metrics formed the SRI and weighed factors involving soil erodibility, road sedimentation abatement features, and stream morphology alteration. The SRI was organized into narrative categories (excellent, good, fair, poor, and very poor) based on the distribution of scores. No excellent sites (scores ≥55) were found in this study, 17 (20.7%) were good (low sedimentation risk), 37 (45.1%) were fair (moderate sedimentation risk), 26 (31.7%) were poor (high sedimentation risk), and two (2.5%) were very poor (high sedimentation risk). There was no significant difference in SRI scores among crossing structure type (round culverts, box culverts, and bridges) (H = 4.31, df = 2, p = 0.058). A future study of the Choctawhatchee watershed involving the same study sites could assess the success of restoration plans and activities based on site score improvement or decline.     

Integrated model of simulated occupant injury risk and real medical costs

Introduction

The purpose of this study was to develop an integrated methodology that links occupant injury risk functions, estimated in the laboratory, with real world medical treatment costs by using the abbreviated injury score (AIS). Using our model, the expected medical treatment costs for crash injuries to various body regions and of different severities can be investigated.

Methods

First, the simulation results are compared with NHTSA crash data. We used a modified kinematics simulation model that incorporates an F = E^b function as a supplement to the previous Steffan's model to obtain a more accurate acceleration history a(t). Second, head injury criteria HIC₃₆ can be calculated from a(t), and we use the injury probability P as a function of HIC_36, as proposed by Kuppa, to obtain the injury risk function for various AIS values. Third, medical treatment cost models for various AIS values can be calculated by using a regression cost model with real world data. Finally, the injury risk function and medical treatment cost models are linked through AIS values. We establish an integrated methodology and predict medical costs and car safety data using real world police reports, medical treatment costs, and laboratory simulation results.

Results

Using head injuries in frontal crashes as an example, we focus on simulation parameters for different vehicle models, with and without airbags. We specifically examine impact closing speed, Delta-V, and impact directions.

Conclusion

Simulation results can be used to supplement insufficient real crash data, in particular ΔV, and injury risk results from police crash reports.

Impact on industry

The proposed integrated methodology may provide the vehicle industry with a new safety assessment method. Real crash data coupling provides consumers with more realistic and applicable information.     

Modeling perceived collision risk in port water navigation

An increase in the likelihood of navigational collisions in port waters has put focus on the collision avoidance process in port traffic safety. The most widely used on-board collision-avoidance system is the automatic radar plotting aid which is a passive warning system that triggers an alert based on the pilot’s pre-defined indicators of distance and time proximities at the closest point of approaches in encounters with nearby vessels. To better help pilot in decision making in close quarter situations, collision risk should be considered as a continuous monotonic function of the proximities and risk perception should be considered probabilistically. This paper derives an ordered probit regression model to study perceived collision risks. To illustrate the procedure, the risks perceived by Singapore port pilots were obtained to calibrate the regression model. The results demonstrate that a framework based on the probabilistic risk assessment model can be used to give a better understanding of collision risk and to define a more appropriate level of evasive actions.     

风险管理在水电工程中的应用

水电工程是一个在建设过程中充满风险的、相当复杂的系统工程,其风险管理伴随着工程建设的全过程.随着我国水电工程建设体制改革的进一步深化,风险管理越来越受到工程界的重视.分析了在水电工程中存在的主要危险有害因素,提出了具体的风险管理和评价方法,并对一些主要的评价方法进行了大致的比较,同时对水电工程的风险管理工作提出了一些改进措施.     

基于知识推理的发电企业设备风险管理应用研究

基于发电企业设备自身的特点及工作人员对风险知识认知的局限性,有必要分析发电企业设备在运行、检修中潜在的风险.分析了设备风险知识与风险管理的关系,并以发电企业各类大型设备中应用最广泛的电动机为例,解决了电动机风险知识的表达及推理问题,为实现基于知识的设备风险管理提供了一种思路,对指导发电企业的设备日常维护、巡检以及状态监测、避免不必要的损失有着积极的意义.     

江河水源地突发性水污染事故风险评价

近年来,我国江河饮用水水源地突发性水质污染事故频发,成为我国面临的最严重的环境问题之一.江河水源地突发性水质污染事件的风险评价是确保饮用水源地水质安全的重要手段,对突发性水质污染事故,采取适当的应急处理措施.     

层次分析法在高层学生公寓火灾危险性评价中的应用

分析高层学生公寓的消防安全特点及其火灾发生危害性,评述现有的高层建筑火灾风险评价方法;在现有的评价方法的基础上,从人员因素、建筑物属性、安全疏散设施、报警与灭火系统、防火与防烟系统、建筑物内电气因素和消防安全管理7个方面综合考虑,建立了高层学生公寓的建筑火灾危险评价指标体系;利用层次分析法对高层学生公寓火灾危险性进行分析,确定其评价指标体系中各层次各指标的权重;分析结果表明:消防安全教育与培训是学生公寓火灾危险评价指标体系中最重要的因素。加强和改进高层学生公寓消防安全管理,对预防或减少高层学生公寓火灾具有现实指导价值。     

聚氨脂泡沫填缝剂生产工艺火灾危险性分析与对策

以聚氨脂泡沫填缝剂基本生产原理及其特点为基础,对生产原料进行火灾危险性分析,结果表明:该类生产场所的火灾危险等级应划分为甲类;提出聚氨酯泡沫填缝剂生产中存在的安全问题及原因;运用危险度评价法对聚氨脂泡沫填缝剂生产工艺的火灾危险性进行了定量的安全评价,得出聚氨脂泡沫填缝剂生产工艺的危险程度为高度危险;并从建筑设计、防火管理和生产工艺等方面提出了预防火灾事故发生的对策。     

基于Petri网的铁路车站安全防护系统建模及可靠性分析

采用单一的随机Petri网对车站线路结构、列车运行过程及车站防护系统建模,基于欧洲电工标准委员会定义的安全目标,确定车站安全防护系统的可靠性需求。对无防护系统的列车入站进行建模和分析,然后基于防护系统功能及可靠性特性,结合列车入站动态特性,对防护系统的功能和可靠性进行建模,并根据安全目标与车站事故率之间的数学关系进行系统的安全分析和可用性分析。其结果表明,车站防护系统的可靠性与乘客的个人风险存在着定量的关系,从而可以依据个人风险的标准来确定防护系统可靠性需求。     

行为安全管理理论在我国的实践困境及其解决途径

行为安全管理理论在我国被广泛宣传与应用,但在概念理解、定量判断及影响因素的分析等方面存在着认识误区,要改变行为安全管理理论在实践中的困境,发挥其应有作用,笔者认为:应首先对理论研究中的相关概念进行规范,加强对我国生产安全事故与行为安全之间的定量关系研究;并将工程技术措施和组织管理措施作为事故风险的控制重点;探索符合我国职工特点的安全教育培训方式,增强企业的安全生产主体责任意识,提高安全投入的有效性,将安全融入到经济与社会发展过程中。只有为行为安全管理理论的实践和应用提供良好的环境和保障,才能进一步提升我国企业的生产安全事故风险控制水平。