“…No additional information or statistical assumption is needed (Goh & Law, 2003;Su & Hsu, 2006). The RST has been successfully applied in a variety of fields such as: business failure prediction (Ahn, Cho, & Kim, 2000;Beynon & Peel, 2001;Dimitras, Slowinski, Susmaga, & Zopounidis, 1999;Slowinski & Zopounidis, 1995), rough neural expert system (Yahia, Mahmod, Sulaiman, & Ahmad, 2000), maximally general fuzzy rules (Hong, Wang, Wang, & Chien, 2000), customer and product fragmentation (Changchien & Lu, 2001), rules from incomplete training examples (Hong, Tseng, & Wang, 2002), stock price mining (Wang, 2003), hierarchical decision rules from clinical databases (Tsumoto, 2003), case-based reasoning application (Huang & Tseng, 2004), travel pattern generation (Witlox & Tindemans, 2004), credit scoring (Ong, Huang, & Tzeng, 2005), bank credit ratings (Griffiths & Beynon, 2005), rule discovery from noisy data (Wang, 2005), group decision (Huang, Ong, & Tzeng, 2006), classification rules (Tsai, Cheng, & Chang, 2006), customer relationship management (Tseng & Huang, 2007), insurance market (Shyng, Wang, Tzeng, & Wu, 2007), drug utilization knowledge (Chou, Cheng, & Chang, 2007), supplier selection (Xia & Wu, 2007), location based services (Sikder & Gangopadhyay, 2007), neighborhood classifiers (Hu, Yu, & Xie, 2008) cross-level certain and possible rules (Hong, Lin, Lin, & Wang, 2008), feature selection (Chen, Tseng, & Hong, 2008), and so on. The basics of RST are explained below.…”