中文摘要：

针对不可分离信息系统的属性粒结构计算问题,提出一种利用分治和增量计算相结合的计算方法。首先,研究了在信息系统函数依赖集上增加新的函数依赖（FD）后,信息系统属性粒结构的变化规律,证明了信息系统结构增量定理;其次,通过移除部分函数依赖,使不可分离信息系统成为可分离信息系统,利用分解定理计算出可分离信息系统结构;然后,将移除的函数依赖加入可分离信息系统,利用增量定理计算出原信息系统结构;最后,给出了计算不可分离信息系统属性粒结构的算法,分析了算法复杂度。与直接计算不可分离信息系统的粒结构相比,该计算方法可将计算复杂度从O（n×m×2n）降低到小于O（n×k×2n）（k

英文摘要：

A computational method utilizing divide-and-conquer and incremental computation was proposed to calculate the structure of attribute granule of an inseparable information system. Firstly, the rule that how the structure of attribute granule of an information system changed when new Functional Dependency （FD） was added to the functional dependency set of an information system was studied and the increment theorem of information system structure was proved. Secondly, by removing a part of the functional dependency, an inseparable information system could become a separable information system and the structure of the separable information system was calculated by using decomposition theorem. Thirdly, the removed functional dependency was added to the separable information system and the structure of the original information system was calculated by using increment theorem. Lastly, the algorithm to calculate the structure of attribute granule of inseparable information system was given and its complexity was analyzed. The complexity of the direct calculation of the structure of attribute granule of information system was O（ n1 × m1 ×2n1）, and the proposed method could reduce the complexity to below O（ n × k ×2n） （ k 〈 m）, and when k = 1,2, the complexity could be reduced to O（ n1 × ml ×2n~） ＋ O（ n2 × m2 × 2n2） （ n = nl ＋ n2, m = m1 ＋ m2）. The theoretical analysis and practical calculation demonstrate that the proposed method can effectively reduce the computational complexity of the structure of attribute granule of an inseparable information system.