原油集输联合站故障树分析研究

采用故障树分析法对原油集输联合站生产工艺流程和危险危害因素进行分析,确定原油集输联合站的故障树因素表,以该站故障为顶上事件,以火灾爆炸、介质泄漏、其他危险作为故障树的中间事件,建立联合站故障树。通过定性定量分析,求取联合站故障树的最小割集为77组,进而确定故障树顶事件的事故发生概率为5.68×10-3和底事件结构重要度,得出影响集输联合站安全性的重要因素为通风不良、储罐密封不良、液体腐蚀、盘管穿孔和人员误操作等。因而提出加强原油集输联合站安全监察和监控措施,及时地发现和处理故障,以提高联合站运行安全可靠性和生产效率。     

和谐社会构建中的企业安全文化建设研究

运用决策树对企业安全文化建设进行最优决策分析发现,企业一般不会自觉地投入资金来进行安全文化建设,而是存在一种侥幸心理,因此,需要对其施加监督外力;通过构建一个由政府安监部门和企业参与的监督博弈模型并进行分析表明,政府安监部门加大对企业不进行安全文化建设的处罚力度并不是最优策略,鼓励并帮助企业进行安全文化建设才是最优选择。和谐社会构建中仍需运用"和谐"原则来指导和帮助企业进行安全文化建设。     

基于模糊故障树的海洋立管破坏失效风险分析

针对海洋立管破坏失效事故资料不完备及发生概率缺乏精确值的现状,提出了基于模糊故障树的海洋立管破坏失效风险分析方法。通过对现有的海洋立管破坏失效事故原因的统计分析,建立了以"海洋立管破坏失效"为顶事件的故障树。在对故障树进行定性分析的基础上,得到了引起海洋立管破坏失效的105个各阶最小割集,确定了海洋立管发生破坏失效的主要模式。采用专家判断法与模糊集理论结合的方法对故障树进行了定量分析,评估了故障树底事件的发生概率,并计算了故障树顶事件的发生概率。通过模糊故障树分析得到了海洋立管系统的薄弱环节,从而可以对其采取有效措施,以降低事故发生概率及提高系统可靠性。     

重大事件对入境游客旅游动机的影响——北京奥运会的案例研究

以2008年北京奥运会为例,通过入境游客行为调查分析奥运会举办对入境游客旅游动机的影响。结果表明,影响入境游客旅游动机的因素主要有限制性因子、社会心理因子和文化教育因子,其中社会心理因子和文化教育因子与北京奥运会显著相关;入境游客的年龄、学历和家庭结构与奥运会举办呈现负相关;游客的年龄、学历、年收入和家庭结构等变量受奥运会影响显著,提出了相应的营销策略。     

Cost-based fire risk assessment in natural gas industry by means of fuzzy FTA and ETA

Fire is the most prevalent accident in natural gas facilities. In order to assess the risk of fire in a gas processing plant, a fault tree analysis (FTA) and event tree analysis (ETA) has been developed in this paper. By utilizing FTA and ETA, the paths leading to an outcome event would be visually demonstrated. The framework was applied to a case study of processing plant in South Pars gas complex. All major underlying causes of fire accident in a gas processing facility determined through a process hazard analysis (PHA). Fuzzy logic has been employed to derive likelihood of basic events in FTA from uncertain opinion of experts. The outcome events in event tree has been simulated by computer model to evaluate their severity. In the proposed methodology the calculated risk has the unit of cost per year which allows the decision makers to discern the benefit of their investment in safety measures and risk mitigation.     

Using an expanded Safety Failure Event Network to analyze railway dangerous goods transportation system risk-accident

In order to improve the reliability and safety of railway dangerous goods transportation system (RDGTS), and prevent the similar accidents happened again, an easier operated, dynamic, systemic and quantitative approach called expanded Safety Failure Event Network (SFEN) is proposed to analyze the past typical RDGTS accidents. The expanded SFEN focuses on transfer the traditional safety occurrence process into a visible Accident Analysis Network (AAN) platform. To improve the previous SFEN approach, the risk factors categories are expanded including Human actions, Technical failure, Nature of transported goods, Environment factors, Management failure and External factors of the system. An AAN is established by using the risk factors as the nodes and using the interactions among these risk factors as the edges, the RDGTS risk analysis problem is transferred into a quantitative network structure analysis problem from a network perspective. After that, based on the AAN, TouchGraph and NetMiner are applied to calculate and rank the centrality degree of each sub-risk factor (or sub-heading) in a network. A RDGTS accident happened in 2001 is analyzed, the results show that TouchGraph and NetMiner can present the same interactions and importance of sub-risk factors (or sub-headings) through visible circle images in the platform, NetMiner is more digital because the results can be presented as the centrality degree values. The greatest contributed sub-risk factors are Equipment maintenance failure and Railway inspection agency failure, followed by cargo packaging problems, illegal entrainment problem. Misbehaves of the freight inspector with centrality degree 0.523810 shows that this sub-heading has the greatest contribution to the accident.     

Reliability and availability modeling of Subsea Xmas tree system using Dynamic Bayesian network with different maintenance methods

Subsea Xmas tree is a vital equipment for offshore oil and gas development. Aiming at the fault mode of subsea Christmas tree system under production conditions, the fault tree of subsea tree system was established, which was transformed into Dynamic Bayesian network, and the reliability and availability of subsea tree system with different repair states are quantitatively analyzed. In this paper, the DBNs are partially verified by the method based on three axes. The results show that the reliability of subsea vertical tree system is slightly higher than that of subsea horizontal tree system. After repair and maintenance, the performance of subsea tree system has been significantly improved, and the improvement of the system performance by preventive maintenance is more obvious. Compared with the perfect repair, the performance of the system with imperfect repair is not significantly reduced. Compared with perfect repair & preventive maintenance, the performance of the system with imperfect repair & preventive maintenance is slightly reduced. In addition, the influence of failure rates and degradation probability on reliability and availability is analyzed. By comparing the influence of failure rates on the system performance of non-maintenance and maintenance, it is found that the change of failure rates has the greatest influence on the reliability and the least influence on the availability of perfect repair & preventive maintenance. By comparing the performance of each component in the subsea tree system, it is found that the failure rates has the most obvious influence on the chock module, and gate valve and tree cap have the most significant influence on the reliability of the system. In order to improve the reliability of subsea tree system, it is necessary to improve the reliability of chock module, gate valve and tree cap.     

Rare event risk analysis – application to iceberg collision

To design an engineering system, testing in extreme conditions is at least recommended if not required. There are ambiguities about how to define an extreme state and how to consider it in the design of a system or its operation. The probability estimation of such an event is challenging due to data scarcity, especially in many engineering domains, e.g. offshore development. In this study, available techniques for analyzing the probability of extreme events are examined for their suitability in engineering applications, and a framework is proposed for rare event risk analysis. The framework is comprised of three phases. In the first phase, the outlier based extreme value theory is implemented to estimate the rare event probability. The maximum likelihood criterion is used to estimate the extreme distribution parameters. In the second phase, the rare event is considered as a heavy tail event, and the tail index is estimated through the Hill and the SmooHill estimator. In the third phase, The uncertainty analysis is conducted, and the risk is computed. The proposed methodology is tested for extreme iceberg risk assessment on large offshore structures in the Flemish Pass basin. For this specific case, the estimated design extreme iceberg speed was 4.31 km/h, with an occurrence probability of 3.61E-06.     

基于事故树方法与三角模糊理论耦合的城市火灾风险分析

以消防安全工程学与系统安全工程理论为基础,结合我国城市发展特征及消防安全管理状况,建立城市区域火灾风险事故树;应用模糊重要度法对事故树基本事件进行排序,把导致火灾的因素进行模糊分级。从模糊概率排序以及分级可以看出,城市区域布局、移动消防力量以及人员素质是制约火灾风险的3个主要因素,并与历年来我国城市火灾发生的主要原因相吻合。笔者认为,要从根本上控制城市火灾风险,严格管理3个主要因素对于我国的城市消防安全管理有着非常积极的意义。     

Science and Decision Making: Water Management and Tree‐Ring Data in the Western United States1

Abstract: Growing populations, limited resources, and sustained drought are placing increased pressure on already over‐allocated water supplies in the western United States, prompting some water managers to seek out and utilize new forms of climate data in their planning efforts. One source of information that is now being considered by water resource management is extended hydrologic records from tree‐ring data. Scientists with the Western Water Assessment (WWA) have been providing reconstructions of streamflow (i.e., paleoclimate data) to water managers in Colorado and other western states (Arizona, New Mexico, and Wyoming), and presenting technical workshops explaining the applications of tree‐ring data for water management for the past eight years. Little is known, however, about what has resulted from these engagements between scientists and water managers. Using in‐depth interviews and a survey questionnaire, we attempt to address this lack of information by examining the outcomes of the interactions between WWA scientists and western water managers to better understand how paleoclimate data has been translated to water resource management. This assessment includes an analysis of what prompts water managers to seek out tree‐ring data, how paleoclimate data are utilized by water managers in both quantitative and qualitative ways, and how tree‐ring data are interpreted in the context of organization mandates and histories. We situate this study within a framework that examines the coproduction of science and policy, where scientists and resource managers collectively define and examine research and planning needs, the activities of which are embedded within wider social and political contexts. These findings have broader applications for understanding science‐policy interactions related to climate and climate change in resource management, and point to the potential benefits of reflexive interactions of scientists and decision makers.