基于变权法的FPSO原油舱火灾风险综合评价

建立FPSO原油舱清洗作业风险评价体系,对清洗过程中的火灾风险进行评价,为决策者应对风险提供科学依据。在使用层次分析法计算原油舱清洗火灾风险评价体系中各指标权重的基础之上,引入变权法,对得到的常权进行微调处理,使综合评价结果更接近实际。依据"海洋石油113"号洗舱作业数据,分别用层次分析法和变权法进行权重计算,并将综合评价值进行对比。分析结果显示:FPSO原油舱火灾风险综合评价体系引入变权法后,评价结果能通过评价值分布状况来调整各指标在综合评价体系中的作用,而且可以突显评价值相对较小的指标对综合评价值的影响,从而为制定风险应对措施提供新思路。     

Estimation of driving style in naturalistic highway traffic using maneuver transition probabilities

Accurately estimating driving styles is crucial to designing useful driver assistance systems and vehicle control systems for autonomous driving that match how people drive. This paper presents a novel way to identify driving style not in terms of the durations or frequencies of individual maneuver states, but rather the transition patterns between them to see how they are interrelated. Driving behavior in highway traffic was categorized into 12 maneuver states, based on which 144 (12 × 12) maneuver transition probabilities were obtained. A conditional likelihood maximization method was employed to extract typical maneuver transition patterns that could represent driving style strategies, from the 144 probabilities. Random forest algorithm was adopted to classify driving styles using the selected features. Results showed that transitions concerning five maneuver states – free driving, approaching, near following, constrained left and right lane changes – could be used to classify driving style reliably. Comparisons with traditional methods were presented and discussed in detail to show that transition probabilities between maneuvers were better at predicting driving style than traditional maneuver frequencies in behavioral analysis.     

A Bayesian Network model for contextual versus non-contextual driving behavior assessment

Driving behavior is generally considered to be one of the most important factors in crash occurrence. This paper aims to evaluate the benefits of utilizing context-relevant information in the driving behavior assessment process (i.e. contextual driving behavior assessment approach). We use a Bayesian Network (BN) model that investigates the relationships between GPS driving observations, individual driving behavior, individual driving risks, and individual crash frequency. In contrast to prior studies without context information (i.e. non-contextual approach), the data used in the BN approach is a combination of contextual features in the surrounding environment that may contribute to crash risk, such as road conditions surrounding the vehicle of interest and dynamic traffic flow information, as well as the non-contextual data such as instantaneous driving speed and the acceleration/deceleration of a vehicle. An information-aggregation mechanism is developed to aggregates massive amounts of vehicle GPS data points, kinematic events and context information into drivel-level data. With the proposed model, driving behavior risks for drivers is assessed and the relationship between contextual driving behavior and crash occurrence is established. The analysis results in the case study section show that the contextual model has significantly better performance than the non-contextual model, and that drivers who drive at a speed faster than others or much slower than the speed limit at the ramp, and with more rapid acceleration or deceleration on freeways are more likely to be involved in crash events. In addition, younger drivers, and female drivers with higher VMT are found to have higher crash risk.     

城市道路隧道与公路隧道的运营风险差异分析

为分析城市道路隧道与公路隧道的运营风险差异，通过运营隧道调研和交通事故数据收集，从隧道本体结构及设施、外界环境、交通特性3方面出发，对城市道路隧道与公路隧道的运营风险进行阐述和对比分析。分析得出： 1）与公路隧道相比，城市道路隧道在结构方面的运营风险较大； 2）城市道路隧道车辆发生重大交通事故的概率较公路隧道低，但对城市交通的影响使其社会风险较高； 3）在城市道路隧道运营风险的防控过程中，应当重点考虑周边环境扰动对于结构安全的影响和运营交通事故所造成的社会影响。     

BOT项目融资风险的模糊综合评价方法研究

BOT是一种新兴的项目融资模式，其本身的特点决定项目公司必然会承担较大的风险。在项目投资决策中，风险的分析与评价是关键。此文分析了BOT项目风险的来源并运用模糊理论建立模糊综合评价模型，为项目公司在选择BOT项目时进行科学的投资决策提供参考。     

一种基于模糊原理的碰撞危险度模型

基于“领域”概念和模糊原理，建立起一个用于确定船舶间碰撞危险度的数学模型。该模型不仅综合考虑了多种因素对碰撞危险度的影响，而且简便易行。通过模拟试验表明：本模型能够很好地反映出实际情况，具有较好的效果。     

提高铁道基础结构的可靠性 确保铁路运输安全

本文对 1999年得到欧盟批准、并由欧盟提供所需资金之半数的课题项目 :“适用于铁道基础结构之作业和后勤保障的方法”的背景做了简要介绍。从安全和可靠性、以可靠性为中心的维修及其实际应用、铁道的基础结构及风险等方面 ,论述了提高铁道基础结构机械装置的可靠性对确保铁路运输安全的重要意义。     

液态CO_2输送管道弯管处冲刷腐蚀数值模拟

由于沿程阻力和外界环境的变化,液态CO_2管道内的CO_2会发生相态转变,含有杂质水的液态CO_2夹带的气态CO_2会对管道弯管处产生冲刷腐蚀。为了描述管道内部的冲刷腐蚀规律,利用ANSYS CFX软件对90°弯管的冲蚀现象进行数值模拟。模拟结果表明:冲蚀速率在弯管段60°~80°之间取得最大值;入口处流体速度由4 m/s增加到12 m/s,管壁的冲蚀速率由3.92×10-6kg/(m2·s)增加到3.47×10-5kg/(m2·s);随着弯管曲率半径增加,最大冲蚀速率产生位置发生前移。研究结果可为长距离液态CO_2管道铺设提供参考。     

疏水装置放水管温度场的数值模拟

水蒸汽管道中的冷凝水由疏水装置排出。为研究极寒地区疏水装置放水管冬季结冰的问题,采用计算流体力学软件Fluent建立了放水管死管段热损失的物理模型,并对管道内部温度场进行模拟分析。模拟结果很好地显示了管道内的温度场,并得到了管道轴线上的温度分布,结果表明:死管段长度对管道内温度场有重要影响。将死管段长度控制在0.2 m以内,可有效避免放水管冷凝水结冰的问题。     

RAMS在城市轨道交通建设管理中的应用

在城市轨道交通建设项目管理中,国际上正在使用一种主动性的隐患管理工具——RAMS管理。在项目规划、设计、建设、调试、运营及维护等各阶段,运营与建设单位共同采取减轻措施,消除安全隐患,以最佳的成本效益持续保证城市轨道交通系统的安全及可靠。目前国内部分城市轨道交通项目已开始运用此工具进行管理,但面临业主、设计院、承包商、监理RAMS管理意识匮乏等问题,需要深入研究如何在城市轨道交通领域应用RAMS管理。以深圳市轨道交通4号线三期工程RAMS管理模式和经验为例,介绍RAMS管理的工作流程及内容,剖析各角色的职能划分,总结工作难点及解决方法,对我国城市轨道交通建设管理中RAMS的推广应用具有积极的作用。