“…Two types of models are considered in the literature: continuous flow models and discrete flow models. Discrete flow models are often considered more realistic for discrete manufacturing but the discrete processing of parts makes the performance analysis difficult especially when simulation is used (Mourani, andal., 1983, and, Song andSun, 2001 ). Continuous flow models (see Hu, and al., 1994, Sharifnia, 1988, Glasserman, 1995, Hu, 1995, Perkins and Srikant, 1998, Veatch and Caramanis, 1999, and Xie, 1989, offer a good approximation of material flows and makes the performance analysis more efficient without the need to track each individual part.…”