“…He pointed out that because customers are not always served in the period in which they arrive, the effective arrival rate in each period needs to be modified to reflect this transfer of demand among periods, and he presents an algorithmic method for doing so. Jennings, Mandelbaum, Massey, and Whitt (1996) suggested an approximation procedure based on an infinite-server system, but a more general way to address the nonstationarity issue is to use simulation to reflect the nonstationary arrivals (e.g., see Brigandi, Dargon, Sheehan, & Spencer, 1994;Kwan, Davis, & Greenwood, 1988;Thompson 1995). Once service requirements are established for each planning period (regardless of how the requirements are obtained), many good methods exist for creating schedules that assign workers to these planning periods (see Thompson, 1997, for an extensive bibliography of mathematical programming approaches and Ingolfsson, Haque, & Umnikov, 2002, for an innovative genetic algorithm approach).…”