A new travel time reliability-based traffic assignment model is proposed to investigate the effects of an advanced transportation information system (ATIS) on drivers' risk-taking path choice behaviours in transpo...A new travel time reliability-based traffic assignment model is proposed to investigate the effects of an advanced transportation information system (ATIS) on drivers' risk-taking path choice behaviours in transportation networks with demand uncertainty. In the model, drivers are divided into two classes. The first class is not equipped with ATIS, while the second class is equipped with ATIS. Different risk-taking path choice behaviours of the two classes are studied, respectively. A corresponding mixed equilibrium traffic assignment model is formulated as a variational inequality problem in terms of path flows, which is solved by a heuristic solution algorithm. Numerical results indicate that the ATIS can influence the drivers' risk-taking path choice behaviours and the total system travel time in transportation networks with demand uncertainty. It is also found that under higher demand levels, the benefits of ATIS for network performance enhancement may be more obvious.展开更多
Due to the rigorous fiscal terms and huge potential risk of risk service contracts,optimizing oil production paths is one of the main challenges in designing oilfield development plans.In this paper,an oil production ...Due to the rigorous fiscal terms and huge potential risk of risk service contracts,optimizing oil production paths is one of the main challenges in designing oilfield development plans.In this paper,an oil production path optimization model is developed to maximize economic benefits within constraints of technology factors and oil contracts.This analysis describes the effects of risk service contract terms on parameters of inputs and outputs and quantifies the relationships between production and production time,revenues,investment and costs.An oil service development and production project is illustrated in which the optimal production path under its own geological conditions and contract terms is calculated.The influences of oil price,service fees per barrel and operating costs on the optimal production have been examined by sensitivity analysis.The results show that the oil price has the largest impact on the optimal production,which is negatively related to oil price and positively related to service fees per barrel and operating costs.展开更多
为了解决装配式建筑吊装施工安全风险评估体系缺失、演化路径不清的共性问题,提高施工安全科学管理水平,提出了一种基于改进决策试验与实验室评估法(Decision Making Trial and Evaluation Laboratory,DEMATEL)的关键风险识别与演化路...为了解决装配式建筑吊装施工安全风险评估体系缺失、演化路径不清的共性问题,提高施工安全科学管理水平,提出了一种基于改进决策试验与实验室评估法(Decision Making Trial and Evaluation Laboratory,DEMATEL)的关键风险识别与演化路径分析方法。基于扎根理论构建装配式建筑吊装施工安全风险评价指标体系,利用基于组合数有序加权算子(Combination Ordered Weighted Averaging,C-OWA)改进直接影响矩阵,建立DEMATEL模型决策矩阵,并通过因果关系图识别关键风险因素,探究关键风险演化路径,以武汉市某工程项目为背景开展实证研究。结果表明:该项目存在X_(1)(工人的专业水平与素质差)、X_(5)(工人的技能培训与安全教育不到位)、X_(15)(人员没有进行定期的安全培训)、X_(18)(现场施工安全管理水平低)、X_(19)(风险意识缺乏)等关键风险因素;在4条基础路径和2条复合路径中,复合路径的权重高于基础路径,随着关键风险之间直接和间接作用的复杂化,发生风险事件的可能性将逐步增加;复合路径除了通过基础路径与关键风险耦合得到以外,还可以通过基础路径的相互作用演化得到。展开更多
为从系统整体角度完成对起落架收放系统的风险辨识和影响分析,将系统理论过程分析(Systematic Theory Process Analysis,STPA)与决策实验室分析-解释结构模型(Decision Making Trial and Evaluation Laboratory Interpretive Structural...为从系统整体角度完成对起落架收放系统的风险辨识和影响分析,将系统理论过程分析(Systematic Theory Process Analysis,STPA)与决策实验室分析-解释结构模型(Decision Making Trial and Evaluation Laboratory Interpretive Structural Modeling,DEMATEL-ISM)相结合来开展分析。首先,定义事故和系统级危险,以民机进近阶段放下起落架为例,运用STPA完成对风险因素的系统化辨识;其次,基于最大平均熵减(Maximum Mean De-entropy,MMDE)算法帮助DEMATEL-ISM模型确定阈值,完成对风险因素影响的重要性分析并识别可能引发系统级危险的风险传递路径,据此挖掘关键致因场景,以给出风险预防建议。结果显示:线路性能退化或失效、位置作动控制组件(Position Action Control Unit,PACU)核心处理器故障为关键原因因素,收放作动筒作动异常、机组成员操作不当、起落架指示灯显示异常、起落架液压选择阀作动异常、PACU信息接收有误为关键结果因素,这些因素均涉及多条可能引发系统级危险的风险传递路径,应予以重点控制。展开更多
基金The National High Technology Research and Development Program of China (863 Program) (No.2006AA11Z209)Youth Science and Technology Foundation of China University of Mining and Technology (No.2007A028)Natural Science Foundation of Beijing (No.9073018)
文摘A new travel time reliability-based traffic assignment model is proposed to investigate the effects of an advanced transportation information system (ATIS) on drivers' risk-taking path choice behaviours in transportation networks with demand uncertainty. In the model, drivers are divided into two classes. The first class is not equipped with ATIS, while the second class is equipped with ATIS. Different risk-taking path choice behaviours of the two classes are studied, respectively. A corresponding mixed equilibrium traffic assignment model is formulated as a variational inequality problem in terms of path flows, which is solved by a heuristic solution algorithm. Numerical results indicate that the ATIS can influence the drivers' risk-taking path choice behaviours and the total system travel time in transportation networks with demand uncertainty. It is also found that under higher demand levels, the benefits of ATIS for network performance enhancement may be more obvious.
基金Funding for this work was provided by the Major Project from the National Social Science Foundation of China through research on replacement strategies for overseas oil and gas resources based on the perspective of China’s petroleum security under the project number 11&ZD164
文摘Due to the rigorous fiscal terms and huge potential risk of risk service contracts,optimizing oil production paths is one of the main challenges in designing oilfield development plans.In this paper,an oil production path optimization model is developed to maximize economic benefits within constraints of technology factors and oil contracts.This analysis describes the effects of risk service contract terms on parameters of inputs and outputs and quantifies the relationships between production and production time,revenues,investment and costs.An oil service development and production project is illustrated in which the optimal production path under its own geological conditions and contract terms is calculated.The influences of oil price,service fees per barrel and operating costs on the optimal production have been examined by sensitivity analysis.The results show that the oil price has the largest impact on the optimal production,which is negatively related to oil price and positively related to service fees per barrel and operating costs.
文摘为了解决装配式建筑吊装施工安全风险评估体系缺失、演化路径不清的共性问题,提高施工安全科学管理水平,提出了一种基于改进决策试验与实验室评估法(Decision Making Trial and Evaluation Laboratory,DEMATEL)的关键风险识别与演化路径分析方法。基于扎根理论构建装配式建筑吊装施工安全风险评价指标体系,利用基于组合数有序加权算子(Combination Ordered Weighted Averaging,C-OWA)改进直接影响矩阵,建立DEMATEL模型决策矩阵,并通过因果关系图识别关键风险因素,探究关键风险演化路径,以武汉市某工程项目为背景开展实证研究。结果表明:该项目存在X_(1)(工人的专业水平与素质差)、X_(5)(工人的技能培训与安全教育不到位)、X_(15)(人员没有进行定期的安全培训)、X_(18)(现场施工安全管理水平低)、X_(19)(风险意识缺乏)等关键风险因素;在4条基础路径和2条复合路径中,复合路径的权重高于基础路径,随着关键风险之间直接和间接作用的复杂化,发生风险事件的可能性将逐步增加;复合路径除了通过基础路径与关键风险耦合得到以外,还可以通过基础路径的相互作用演化得到。
文摘为从系统整体角度完成对起落架收放系统的风险辨识和影响分析,将系统理论过程分析(Systematic Theory Process Analysis,STPA)与决策实验室分析-解释结构模型(Decision Making Trial and Evaluation Laboratory Interpretive Structural Modeling,DEMATEL-ISM)相结合来开展分析。首先,定义事故和系统级危险,以民机进近阶段放下起落架为例,运用STPA完成对风险因素的系统化辨识;其次,基于最大平均熵减(Maximum Mean De-entropy,MMDE)算法帮助DEMATEL-ISM模型确定阈值,完成对风险因素影响的重要性分析并识别可能引发系统级危险的风险传递路径,据此挖掘关键致因场景,以给出风险预防建议。结果显示:线路性能退化或失效、位置作动控制组件(Position Action Control Unit,PACU)核心处理器故障为关键原因因素,收放作动筒作动异常、机组成员操作不当、起落架指示灯显示异常、起落架液压选择阀作动异常、PACU信息接收有误为关键结果因素,这些因素均涉及多条可能引发系统级危险的风险传递路径,应予以重点控制。