基于加权阈值容差关系的不完备信息系统粗糙集模型

Rough set model of incomplete information systems based on the weighted threshold tolerance relation

针对已有的不完备信息系统粗糙集扩充模型没有考虑属性的权重的缺点,提出基于加权阈值容差关系的粗糙集扩充模型.该模型根据给出的不完备信息系统信息量计算权重,不需引入系统外知识,权重确定比较客观;同时引入阈值来调整加权阈值容差类判定的严格程度,兼顾了人的主观要求,并能预先排除因自身不满足阈值条件而不可能与任何其他对象划为同一加权阈值容差类的对象,但不影响类的完整性.实例对比分析表明,与其他模型相比,基于加权阈值容差关系的粗糙集扩充模型符合不完备信息系统应用客观实际,具有更强的适应能力.

In order to overcome the shortage that attribute weights are not taken into consideration in the existing extensions of rough sets under incomplete information systems,a new rough set model is proposed based on the weighted threshold tolerance relation.The new model calculates the weights according to the information quantity of the incomplete information system without outside knowledge,so the weights are objective.Moreover,the model introduces a threshold to adjust the strictness degree of the weighted threshold tolerance class,which not only combines subjective requirements into consideration,but also excludes objects in advance that do not reach the threshold and can not be in the same weighted threshold tolerance class with other objects.This exclusion will not influence the completeness of the classes.Contrastive analysis of an example shows that the proposed extension of a rough set based on the weighted threshold tolerance relation accords with the fact of an incomplete information system and is more applicable compared with other models.