Current Slide

Rough Set Approach

• Rough sets are used to approximately or “roughly” define equivalent classes
• A rough set for a given class C is approximated by two sets: a lower approximation (certain to be in C) and an upper approximation (cannot be described as not belonging to C)
• Finding the minimal subsets (reducts) of attributes for feature reduction is NP-hard but a discernibility matrix (which stores the differences between attribute values for each pair of data tuples) is used to reduce the computation intensity