组合频率 meaning in English

combination frequencies
combination frequency

The methods of the risk analysis on the economic benefits of the water conservancy projects are studied herein ; in which several practical models with various methods for the estimation on the risks from the economic benefits of water conservancy are presented with the actual cases
摘要对水利经济效益风险分析的方法进行了研究，并结合实际提出了水利经济效益风险评价的几种行之有效的实用模型，包括组合频率法、风险分析的最大熵模型、基于模糊性的风险分析方法。