Modeling Finite‐Time Failure Probabilities in Risk Analysis Applications

In this article, we introduce a framework for analyzing the risk of systems failure based on estimating the failure probability. The latter is defined as the probability that a certain risk process, characterizing the operations of a system, reaches a possibly time‐dependent critical risk level within a finite‐time interval. Under general assumptions, we define two dually connected models for the risk process and derive explicit expressions for the failure probability and also the joint probability of the time of the occurrence of failure and the excess of the risk process over the risk level. We illustrate how these probabilistic models and results can be successfully applied in several important areas of risk analysis, among which are systems reliability, inventory management, flood control via dam management, infectious disease spread, and financial insolvency. Numerical illustrations are also presented.     

Poliovirus Surveillance by Examining Sewage Water Specimens: Studies on Detection Probability Using Simulation Models

Efficiency of environmental surveillance of poliovirus circulation was studied using simulation models. First, three transmission models were defined for describing different scenarios of poliovirus infections in a large unstructured population. Second, environmental factors, such as the total volume of the sewage network and losses of viruses, were modeled for computing the virus output at the sewage sampling site. Third, the effect of sampling and laboratory procedures was accounted for in the probability of detection, given the amount of polioviruses in a specimen. The simulation model can be used for theoretical assessments of the likely efficiency of environmental surveillance, compared with acute flaccid paralysis (AFP) surveillance. Under reasonable assumptions in a vaccinated population, the AFP surveillance can be outperformed if the poliovirus outbreak is not large. However, this depends on the assumed case-to-infection ratio and on the sampling frequency of the sewage water specimens. Increasing the latter will lead to a higher detection probability, which will further enhance the method based on environmental surveillance.     

The Effectiveness of Risk Management: An Analysis of Project Risk Planning Across Industries and Countries

This article examines the effectiveness of current risk management practices to reduce project risk using a multinational, multi‐industry study across different scenarios and cultures. A survey was administered to 701 project managers, and their supervisors, in seven industries and three diverse countries (New Zealand, Israel, and Japan), in multiple languages during the 2002–2007 period. Results of this study show that project context—industry and country where a project is executed—significantly impacts perceived levels of project risk, and the intensity of risk management processes. Our findings also suggest that risk management moderates the relationship between risk level and project success. Specifically, we found that even moderate levels of risk management planning are sufficient to reduce the negative effect risk levels have on project success.     

合同案件民事审判中法官自由裁量权刍议——以对事实的认定为例

合同案件民事审判中法官自由裁量权主要包括举证责任分配的自由裁量,判断证据之证据能力即合法性的自由裁量和适用证明标准的自由裁量。当前,合同案件民事审判中法官自由裁量质量不高且比较混乱,基本没有规则可循。要搞好合同案件民事审判中法官对事实认定的自由裁量,必须在思想和组织上高度重视,加强对事实认定方面在判决书中的说理和公开审判制度,加强监督和对错案的纠正。     

On the Effect of Probability Distributions of Input Variables in Public Health Risk Assessment

A central part of probabilistic public health risk assessment is the selection of probability distributions for the uncertain input variables. In this paper, we apply the first-order reliability method (FORM)^(1–3) as a probabilistic tool to assess the effect of probability distributions of the input random variables on the probability that risk exceeds a threshold level (termed the probability of failure) and on the relevant probabilistic sensitivities. The analysis was applied to a case study given by Thompson et al. ⁽⁴⁾ on cancer risk caused by the ingestion of benzene contaminated soil. Normal, lognormal, and uniform distributions were used in the analysis. The results show that the selection of a probability distribution function for the uncertain variables in this case study had a moderate impact on the probability that values would fall above a given threshold risk when the threshold risk is at the 50th percentile of the original distribution given by Thompson et al. ⁽⁴⁾ The impact was much greater when the threshold risk level was at the 95th percentile. The impact on uncertainty sensitivity, however, showed a reversed trend, where the impact was more appreciable for the 50th percentile of the original distribution of risk given by Thompson et al. ⁴ than for the 95th percentile. Nevertheless, the choice of distribution shape did not alter the order of probabilistic sensitivity of the basic uncertain variables.     

具有生存性的WDM网络性能分析

研究了在动态业务量时,可调谐光收发器和波长变换器对生存性WDM网络性能的影响。通过在NSFNET、CERNET、MESH-TORUS网络中的仿真,又从网络阻塞率方面研究了两者对WDM网络性能的影响。研究结果表明,在业务量为动态的生存性WDM网络中,可调谐光收发器和波长变换器对网络的性能都有显著的提高,但波长变换器对网络性能的改善要大于可调谐光收发器。     

教会大学建筑与中国传统建筑艺术的复兴

19世纪末至20世纪30年代期间,中国教会大学在特殊的历史环境中,首先倡导了中西合璧式建筑新式样,拉开了中国传统建筑艺术复兴的序幕。在此之后,由于国内民族意识逐渐觉醒,这种建筑新式样又被视为弘扬和继承中国传统文化的表象参照物,并逐渐发展成为一种具有特殊意义的现代建筑风格。中国教会大学的建筑形态构成以及由此而导致的中国传统建筑艺术复兴,是中西文化双向流动的特殊案例和有形史料。     

大学生创新实验在工科院校生物类专业中的实践与模式

大学生创新实验是大学生在导师的指导下充分发挥自身能动性的教学实践,具有多种模式。这项行动,对参与学生本身而言,是一次难得的将理论与实践相结合的机会——开阔了视野,锻炼了能力,也能让学生对以后的发展有更清醒的认识;对高校和教育者而言,是一次新的教学形式的尝试,也能使其更好地完成教书育人的使命。     

体验式教学模式在大学英语教学中的应用

根据建构主义、学生中心论、自主学习论和N unan的体验模式教学在教学过程中主要采用任务教学法,探索一种体验式的教学模式,来突出学生的主体地位,培养英语综合运用能力和自主学习能力。     

实现祖国统一是历史赋予中国共产党的使命

祖国统一是中国历史发展的主流,是中国人民的基本要求,是中华民族的根本利益所在。本文主要论述了中国共产党以人民的需求和民族的利益作为自己的最高行动准则,他们顺应历史发展趋势,了解人民的愿望和要求,代表国家和民族的利益,把完成祖国统一大业看成是历史赋予中国共产党的神圣使命。