Algorithms and Algorithm Analysis of Logical and Operation of Grade Approximation Operators

Grade is an important index for quantitative research, and graded rough set model is an important extended rough set model. This paper aims to study logical AND operation of grade approximation operators and its algorithms in graded rough set model. Based on logical AND requirement of grade index, logical AND operation of grade approximation operators is proposed and analyzed, and its essence and basic structure are obtained. Both conventional algorithm and microscopic algorithm are proposed and analyzed, and a conclusion is drawn that microscopic algorithm has more advantages in contrast to conventional algorithm. Finally, logical AND operation of grade approximation operators and its algorithms are illustrated by an example.