A belief network is a new mechanism for knowledge representation based on probability the-ory. Its distinct performance in representing and reasoning about uncertainty makes it a hot researchtopic in artificial intelligence. It is now being Used in many areas. In this paper,we give a comprehensiveintroduction to a belief network,including its historic background ,principles ,the progress of its researchand development ,and some challenging problems.
The study of mathematical models on information retrieval is an important area in the Information Retrievalcommunity. Because of the uncertainty characteristic of IR,the probability model based on statistical probability is apromising model from recent to future. Those models can be classified into classical models and probability networkmodels. Several famous models are introduced and their shortcomings are pointed out in this paper. We also clarifythe relationship of these models and introduce a new models based on statistical language model curtly.
