“…Furthermore, problem structuring continues to be of significant interest. See for example Kirkwood (1997) and Ragsdale (2004) Roy (1998), Kouvelis and Sayin (2006), Deb and Gupta (2005), and Wang and Zionts (2006), along with the interesting work on rough sets, based on Pawlak's original idea (Pawlak, 1982; see also Slowinski, 1992, and the discusssion in section 4.2 below). Furthermore, many interval-valued methods provide robust solution approaches, including PAIRS for value tree analysis (Salo and Hämäläinen, 1992) and Robust Portfolio Modeling (Liesiö et al, 2007).…”