涉氨企业的消防安全现状与防火对策

根据近年来涉氨企业在生产、经营和生活过程中发生氨气泄漏,引发火灾、爆炸等安全事故所造成的人员伤亡等惨痛教训,对涉氨企业当前的消防安全现状进行了深入的调研,对该类场所存在的消防安全问题及其原因进行了分析,提出了解决消防安全问题的对策。     

Return policy: Hassle‐free or your money‐back guarantee?

This article compares the profitability of two pervasively adopted return policies—money‐back guarantee and hassle‐free policies. In our model, a seller sells to consumers with heterogeneous valuations and hassle costs. Products are subject to quality risk, and product misfit can only be observed post‐purchase. While the hassle‐free policy is cost advantageous from the seller's viewpoint, a money‐back guarantee allows the seller to fine‐tune the consumer hassle on returning the product. Thus, when the two return policies lead to the same consumer behaviors, the hassle‐free policy dominates. Conversely, a money‐back guarantee can be more profitable even if on average, high‐valuation consumers experience a lower hassle cost than the low‐valuation ones. The optimal hassle cost can be higher when product quality gets improved; thus, it is not necessarily a perfect proxy or signal of the seller's quality. We further allow the seller to adopt a mixture of these policies, and identify the concrete operating regimes within which these return policies are optimal among more flexible policies. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 403–417, 2014     

基于检测的人体跟踪算法

传统的目标跟踪算法需要人为标定跟踪区域,且受到漂移问题的影响。为了解决这些困难,针对人体跟踪问题,提出了一种新的基于检测的跟踪算法。为了减少漏跟踪,使用了多个检测算子,用来定位多个身体部位,将其检测结果映射到一个相同的身体区域。为了适应快速运动的目标,使用KLT跟踪和凝聚聚类将检测窗口连接起来形成人体轨迹。实验结果表明:使用多个检测算子明显地提高了跟踪性能;KLT跟踪对于快速运动目标具有适应能力。该算法基本满足实时性。     

惯组动态测试台误差分析及附加运动补偿算法

为了完成惯组的高精度、大动态测试任务,基于Gough-Stewart平台设计了电动六自由度惯组动态测试台。建立了系统的误差模型并分析了电动缸长度误差对系统精度的影响,分析了电动缸在惯组动态测试台运动过程中产生的被动螺旋附加运动,并对该运动补偿算法进行了研究。对被动螺旋附加运动产生的误差进行量化分析,结果表明,被动螺旋附加运动对惯组动态测试台的位姿精度存在非常显著的影响。为了消除该影响,编制了补偿算法,并将其应用于惯组动态测试台的实时控制系统中。实验结果表明,经过算法补偿后,惯组动态测试台的位姿精度达到了设计指标要求。     

On the Determinants of Terrorism Risk Concern in Europe

We investigate whether differences in terrorism risk are mirrored on terrorism risk perception across European countries for the period 2003–2007. We find that the average propensity for terrorism risk concern is affected by actual risk levels. Country and individual heterogeneity contribute substantially to the variation of observed risk perception. Singles and individuals with white collar jobs are less likely to mention terrorism as one of the most pressing issues their country faces, while political positioning towards the right makes it more likely to be concerned about terrorism. As far as competing risks are concerned, we find that the likelihood terrorism is mentioned, decreases with spending on pensions as a percentage of GDP being higher. Finally, based on the Bayesian framework, we also examined the formation of terrorism risk perceptions, and decompose the observed country-level time series of terrorism activity into a long- and a short-run component. We concluded that the observed risk perception variation is only explained by the long-term trend of terrorism activity countries face.     

NO SUCH THING AS A FREE LUNCH

The funding of international nuclear risk mitigation is ad hoc, voluntary, and unpredictable, offering no transparent explanation of who is financially responsible for the task or why. Among many non-nuclear-armed states, this exacerbates a sense of injustice surrounding what they see as a discriminatory nuclear regime. The resulting erosion of the regime's legitimacy undermines support for efforts to prevent nuclear weapons dissemination and terrorism. This article proposes a transparent, equitable “nuclear-user-pays” system as a logical means of reversing this trend. This system envisions states contributing financially to international efforts to mitigate nuclear risks at a level relative to the degree of nuclear risks created by each state. “National nuclear risk factors” would be calculated by tabulating the risks associated with each state's civilian and military nuclear activities, as well as advanced dual-use and nuclear-capable missile activities, multiplying the severity of each risk by the probability of it occurring, and combining these results. A nuclear-user-pays model would create financial incentives for national and corporate nuclear risk mitigation, boost legitimacy and support for nuclear control efforts among non-nuclear-armed states, assist in preventing nuclear weapons dissemination and terrorism, and advance nuclear disarmament by helping progressively devalue nuclear weapons.     

地球外部空间扰动引力并行计算

针对传统的司托克斯积分方法计算量大、模型复杂的缺点,通过将地球球面以适当的经纬度差进行划分及合理简化,实现了司托克斯积分法计算外部空间扰动引力的积分方程的离散化,建立了地球扰动引力的快速计算模型,并在快速计算模型的基础上采用并行计算技术,实现扰动引力的实时计算。仿真结果表明,提出的快速并行计算模型能较好地实现地球扰动引力的快速、高精度计算。     

运载火箭摄动制导导引系数实时计算方法

对于新型运载火箭,没有相近型号导引系数数据供参考,采用传统试探法计算量大,在制导方案初期论证中不能满足多方案快速计算的需求。在引入理想弹道剩余飞行速度概念的基础上,提出导引系数实时计算方法。本方法对当前实时状态参数和后续飞行段弹道进行了综合考虑,通过数字仿真表明导引精度高于传统常系数导引方法。由于本方法对导引能力进行了预估,因而制导指令不会剧烈变化,易于姿态控制系统的设计实现。同时,由于采用完全解析法,对箭载计算机计算能力要求几乎没有增加,易于工程实现。     

高层建筑安全疏散设计探析

近年来我国高层建筑剧增,承载的人口越来越密集,火灾荷载越来越大,如果安全疏散设计不合理,一旦发生火灾,容易造成严重后果.在分析高层建筑的火灾特点和影响人员安全疏散的因素的基础上,从合理设置安全出口、疏散走道、疏散楼梯、疏散宽度和距离、疏散门、避难层及其他辅助疏散设施、疏散照明灯具等方面探析了高层建筑的安全疏散设计,为避免和减少人员伤亡和财产损失创造条件.     

模糊综合评判的装备研制风险评估

装备研制风险评估是在风险分析的基础上对所研究阶段的风险性进行评估,计算该阶段的风险得分,最终确定其风险等级,对结果进行比较分析,为下一步工作的开展确定方向,具有重要的指导意义.对装备研制的风险管理进行了研究.针对装备研制项目阶段特点,从风险管理工作的现实需求出发,以风险管理的基本理论为基础,结合其他领域已有的风险管理模型,建立了装备研制风险管理的针对性模型,并结合事例对装备研制风险管理模型的具体应用进行了说明.