关键词: 相关分值, 混合模型, 多站点融合

Abstract: In order to increase the retrieval performance，the fusion method based on the mixture mode of Gaussian distribution and exponential distribution is used to combine multi-sites of the distributed retrieval system.It describes the relevance score distribution of the relevant and non-relevant document respectively using the Gaussian density function and the exponential density function.Based on the mixture model，the relevance scores of documents are normalized and combined.The difference of the relevance score distribution between relevant and non-relevant documents is considered in the fusion method，so the relevance score can be counted precisely.A greater weighting can be assigned to the better performance site to increase the retrieval average precision.The experimental results indicate that the mixture fusion method has better performance than other fusion methods.

Key words: relevance score, mixture model, multi-sites fusion