“…To confront this problem, traditional models are designed to improve IA. For example, a number of researches have been focused on constraint satisfactory problems (Allen and Koomen 1983;Haddawy 1996;Ladkin and Maddux 1994;Meiri 1996;Mouhoub, Charpillet, and Haton 1998;Nebel 1997;Pirri and Reiter 1995;Schwalb, Kask, and Dechter 1994;Vilain and Kautz 1986) and solving tractable subclasses of Allen' s interval algebra (Nebel and Burckert 1995;Schwalb and Dechter 1997;Schwalb 1997;Tolba, Charpillet, and Haton 1991;Vila and Reichgelt 1996). However, propagating temporal relations is still non-tractable in general (Nebel and Buckert 1995;Nebel 1997) .…”