Paradoxes of rationality in road safety policy

Rationality is an ideal for transport safety policy. As developed within normative welfare economics, rationality denotes the efficient use of safety measures based on cost–benefit analyses that include all relevant impacts of the measures. Efficiency in the technical sense of the term provides a perfectly clear and precise guideline for policy priorities. Nevertheless, some choices that are guided by cost–benefit analysis may strike us as paradoxical or counterintuitive. A paradox of rationality refers to any situation in which conflicting choices can both be defended as rational. This paper discusses a number of choices that may seem paradoxical. The first involves the choice between options that have identical impacts on safety, but in which these impacts are valued differently. The second deals with the tendency for preference reversals to occur when preferences for the provision of safety are aggregated. The third discusses the inability of conventional measures of willingness-to-pay to reflect the intensity of preferences. The fourth concerns the tendency for policy choice to favour the rich at the expense of the poor when willingness-to-pay is not adjusted for the marginal utility of money. A fifth situation refers to the fact that a policy option that looks attractive ex ante may fail an ex post compensation test because utility functions depend on health state. There is a potential conflict between individual and collective rationality with respect to the costs and benefits of some road safety measures. When developing a road safety programme, a set of road safety measures whose benefits exceed the costs when considered as stand-alone measures could have benefits smaller than cost when combined in a programme consisting of all the measures. Finally, there is a potential conflict between efficiency and negotiated consensus as mechanisms of resource allocation in the public sector. The sources of the paradoxes and ways of avoiding them are discussed. Some of the paradoxes can be avoided if changes in risk are valued in terms of a fixed price per unit of risk rather than according to a non-linear demand function.     

Comparing the fatality risks in United States transportation across modes and over time

This paper analyzes the transportation fatality risk in the United States. The analysis is in two parts. The first part compares the relative risks of the different modes based on data for the decade from 2000 to 2009. The second part is a time-series analysis for each mode using annual data from 1975 to 2010. By almost any measure, transportation is considerably safer now than it was in the mid 1970s. The improvement is especially noticeable for commercial modes such as aviation, railroads and maritime. Even the risks from private highway driving have halved during the past thirty-five years.     

Modeling yard crane operators as reinforcement learning agents

Due to the importance of drayage operations, operators at marine container terminals are increasingly looking to reduce the time a truck spends at the terminal to complete a transaction. This study introduces an agent-based approach to model yard cranes for the analysis of truck turn time. The objective of the model is to solve the yard crane scheduling problem (i.e. determining the sequence of drayage trucks to serve to minimize their waiting time). It is accomplished by modeling the yard crane operators as agents that employ reinforcement learning; specifically, q-learning. The proposed agent-based, q-learning model is developed using Netlogo. Experimental results show that the q-learning model is very effective in assisting the yard crane operator to select the next best move. Thus, the proposed q-learning model could potentially be integrated into existing yard management systems to automate the truck selection process and thereby improve yard operations.     

用间接荧光抗体法检测白细胞间介素2受体

本实验用间接荧光抗体法检测了30名正常人淋巴细胞膜上白细胞间介素2受体(IL-2R)的表达情况,并对影响因素进行了探讨。结果发现随PHA 刺激量增大,IL-2R 表达量也增加;用同一PHA 刺激量时,IL-2R 表达与细胞浓度有关,在细胞浓度为1×10~9细胞/L 时,受体表达最为充分。1×10~9细胞/L 的淋巴细胞悬液经100mg/L PHA 刺激培养24、48和72小时后,IL-2R 表达阳性率分别为52.92±9.11%,72.80±8.12%和87.26±6.09%。本法操作较为简便,适用于临床免疫学检查。     

高血压脑出血患者细胞免疫及IL-2、sIL-2R表达的意义

目的　研究高血压脑出血患者外周血中红细胞免疫和T淋巴细胞亚群的改变以及白细胞介素 2 (IL 2 )、可溶性白细胞介素 2受体 (sIL 2R)表达的变化规律 ,探讨它们之间相互关系及临床意义。方法　采用酶联免疫吸附 (ELISA)法测定患者IL 2、sIL 2R的含量 ,免疫粘附法测定红细胞免疫活性及其调节功能 ,S P(链亲和素 过氧化物酶 )一步法测定CD3、CD4、CD8的细胞数。结果　高血压脑出血组IL 2含量较对照组明显降低 (P <0 .0 5 ) ,sIL 2R则明显升高 (P <0 .0 5 ) ;红细胞C3b受体 (RBC .C3bR)、红细胞免疫调节促进因子 (RFER)明显降低 (P <0 .0 0 1) ,红细胞免疫复合物 (RBC .ICR)、红细胞免疫调节抑制因子 (RFIR)则明显升高 ;CD3、CD4细胞数明显降低 (P <0 .0 1) ,CD8无明显差异 (P >0 .0 5 )。结论　高血压脑出血患者出现免疫功能低下。通过临床检测患者IL 2、sIL 2R含量、红细胞免疫功能、T细胞亚群活性在高血压脑出血的发生、发展、治疗、转归及预后方面具有重要的临床指导意义     

JeRail(R) CBTC城市轨道交通信号系统的安全开发和认证历程

CBTC(基于通信的列车控制)系统是城市轨道交通的关键系统,对其安全性有着决定性影响.富欣智控基于成熟高效的安全产品开发体系,从流程、组织架构、安全和质量保障方面确保自主知识产权的JeRail(R) CBTC城市轨道交通信号系统满足功能安全要求,并最终通过第三方权威机构认证.富欣智控制定合理的策略,从易到难,从子系统到系统集成,从产品认证到工程项目认证一步一个台阶,顺利完成了自主化JeRail(R) CBTC系统的安全开发和认证.介绍了JeRail(R) CBTC城市轨道交通信号系统的安全开发和认证历程.     

趋势项分离预测模型及重标度极差分析在深基坑变形预测中的应用研究

为解决基坑变形预测精度低的问题,利用小波去噪和卡尔曼滤波对基坑变形序列进行去噪处理,分离趋势项及误差项,并利用支持向量机和BP神经网络分别对趋势项和误差项进行预测,以掌握基坑的变形规律及发展趋势;同时,采用重标度极差分析(R/S分析)对基坑的变形趋势进行判断,以验证变形预测的可靠性。根据实例检验,得出小波去噪的去噪效果较好,且预测结果的相对误差均值为1.03%,方差值为0.083,预测精度较高;基坑的变形序列与速率序列均具有持续增长的趋势特征,与变形预测结果一致,验证了预测思路的有效性。     

大跨径混凝土拱桥地震响应分析及减震控制目标研究

通过分析一典型大跨径混凝土拱桥的地震响应结果,得出,对大跨径混凝土拱桥而言,当其在不大的位移响应下,其内力及应力响应显著。因此,常规以位移控制为手段进行的减震方式对大跨径混凝土拱桥而言效果不显著。结合各类地震规范,比较混凝土拱桥与建筑结构在结构上与功能上的不同,提出位移响应及位移减震控制效果不宜作为混凝土拱桥的主要减震控制目标。     

采用GSM-R的机车同步操控车载通信设备可靠性设计

介绍采用GSM-R的机车同步操控车载通信设备(以下简称OCU设备)的可靠性建模和可靠性预计,分析样品的可靠性预计数据,并对设计进行了改进.     

航空货物运量分形预测及R／S分析

航空货运量预测是航空公司运力安排的重要参考。本文根据分形拼贴定理,由分形插值方法求取一个吸引子与航空货运量历史数据相近的迭代函数系统,建立分形预测模型,对航空货运量进行预测。预测结果表明,该方法不存在收敛性问题,数据收集简单,具有较好的实用性。货运量时间序列R/S分析进一步表明了预测值的合理性。