Safety management of waterway congestions under dynamic risk conditions—A case study of the Yangtze River

With the continuous increase of traffic volume in recent years, inland waterway transportation suffers more and more from congestion problems, which form a major impediment to its development. Thus, it is of great significance for the stakeholders and decision makers to address these congestion issues properly. Fuzzy Techniques for Order Preference by Similarity to an Ideal Solution (TOPSIS) is widely used for solving Multiple Criteria Decision Making (MCDM) problems with ambiguity. When taking into account fuzzy TOPSIS, decisions are made in a static scenario with fixed weights assigned to the criteria. However, risk conditions usually vary in real-life cases, which will inevitably affect the preference ranking of the alternatives. To make flexible decisions according to the dynamics of congestion risks and to achieve a rational risk analysis for prioritising congestion risk control options (RCOs), the cost-benefit ratio (CBR) is used in this paper to reflect the change of risk conditions. The hybrid of CBR and fuzzy TOPSIS is illustrated by investigating the congestion risks of the Yangtze River. The ranking of RCOs varies depending on the scenarios with different congestion risk conditions. The research findings indicate that some RCOs (e.g. “Channel dredging and maintenance”, and “Prohibition of navigation”) are more cost effective in the situation of a high level of congestion risk, while the other RCOs (e.g. “Loading restriction”, and “Crew management and training”) are more beneficial in a relatively low congestion risk condition. The proposed methods and the evaluation results provide useful insights for effective safety management of the inland waterway congestions under dynamic risk conditions.     

基于综合权重理论和Fuzzy-TOPSIS综合评价的电网静态电压稳定性分析

随着电网建设规模的不断扩大与结构日益复杂,电网电压安全稳定问题日益突出。探讨了一种静态电压稳定性指标综合辨识方法。首先,针对以往单一评估指标而导致的评估结果差异性问题,釆用六种静态电压稳定性指标来表征节点电压稳定性。其次,对指标权重系数进行优化,分析指标权重不确定性因素,引入信息熵与层次分析法计算指标综合权重。同时以综合评价值最大和评价值偏离度最小为目标,构建拉格朗日函数优化权重系数;并采用Fuzzy-TOPSIS对计算结果进行排序。最后选用哈密地区部分电网作为案例,分别计算单一指标与所提的综合指标辨识系统稳定与薄弱母线,验证所提方法的有效性与客观性。所得结果可以为系统运行规划,无功补偿等提供依据。     

基于模糊TOPSIS方法的预警机巡逻空域配置方案排序

影响预警机巡逻空域配置的相关指标都是定性的,为了能够对这些指标进行数学化描述,运用模糊TOPSIS方法解决这个问题,实现了预警机巡逻空域配置的方案排序,给指挥员提供正确决策.最后通过一个实例对该方法的可行性及实用性进行了检验.