Rough Set Theory In Knowledge Acquisition

It is the core problem of the research of rough set theory that Knowledge acquisition based on Rough Set Knowledge acquisition based on Rough Set,and Inconsistent information system and Incomplete Information System have been key and hot problem in the field,the research of this topic launches from this both side exactly.First,the rough set theory limited in Inconsistent information system has two drawbacks:one drawback is When the system complications increase, control to withdraw the rule and may throw to lose a great deal of important rule with the certain support or variable accuracies.The other drawback is Most methods can't handle the big database and dynamic state databases effectively.Efficacy is defined to make up drawbacks of normal Rough set method in data mining,and give an algorithm for incremental generation about effective decision.Experiment results show that the algorithm have abilities of handling data in large database and processing dynamic data effectively,and can effectively filter out noise and improve efficiency of existing algorithms for mining default rules.The next in order,because of the indetermination of empty value knowledge,the people's processing to the not complete information system, still is a method that fills the value regardless under the not complete information system to thick gather the expand of theories,all bring the influence of the subjective factor upon the original system inevitably. This text passes to carry on the generous character to the indetermination degree of the empty value,making use of the risk value,building up the risk to analyze thick gather the model.That model overcame availably existing and thick gather the shortage of the model,is the reasonable mode of a kind of information system with not complete new processing, have to certainly apply the value.