record some information.Therefore,an organization is represented as the following structure, Organization Record Member List:Record the name of each member in this organization; Attribute Type:Record the type of each attribute in this organization,that is,fixed-value attribute,useful attribute, or others; Organization Type:Record the type of this organization,that is,trivial organization,abnormal organization,or normal organization; Member class:Record the class name of all members; Fitness:Record the fitness of this organization; End. B.Fitness function for organizations After analyzing the relation between attributes and examples,we think that there are two factors to be considered in devising the fitness function for organizations, (1)The number of members:The more members an organization has,the better the quality of the rule extracted from it.Therefore,the fitness of an organization should increase with the number of members. (2)The number of useful attributes:Useful attributes will be used to generate rules at the end of the evolutionary process.The more useful attributes are,the more conditions the rules have.In fact,the more conditions a rule has,the fewer examples the rule covers.But over-generalization will result if the conditions are too few.Therefore,the fitness of an 1010 record some information. Therefore, an organization is represented as the following structure, Organization = Record Member_List: Record the name of each member in this organization; Attribute_Type: Record the type of each attribute in this organization, that is, fixed-value attribute, useful attribute, or others; Organization_Type: Record the type of this organization, that is, trivial organization, abnormal organization, or normal organization; Member_Class: Record the class name of all members; Fitness: Record the fitness of this organization; End. B. Fitness function for organizations After analyzing the relation between attributes and examples, we think that there are two factors to be considered in devising the fitness function for organizations, (1) The number of members: The more members an organization has, the better the quality of the rule extracted from it. Therefore, the fitness of an organization should increase with the number of members. (2) The number of useful attributes: Useful attributes will be used to generate rules at the end of the evolutionary process. The more useful attributes are, the more conditions the rules have. In fact, the more conditions a rule has, the fewer examples the rule covers. But over-generalization will result if the conditions are too few. Therefore, the fitness of an