An AS/R system is being designed for 42  48 unit loads that are 42 high. One of the design alternatives involves eight aisles, no transfer cars, 1,100 openings per aisle, 11 levels and 50 columns of storage on each side of the aisle, and sprinklers. The S/R will travel horizontally at an average speed of 300 fpm; simultaneously, it will travel vertically at an average speed of 70 fpm. The time required for the shuttle to perform either a pickup (P) or a deposit (D) operation is 0.35 minute. Each S/R will have to store and retrieve at a rate of 18 storages per hour and 18 retrievels per hour. Due to the uncertainty concerning the proportion of the operations that will be single command versus dual command, you are to determine the maximum percentage of singlecommand operations so that utilization of the S/R does not exceed 85%. Also, the costs of the building, rack, and S/R machines are to be determined. Assume 2,000 lb loads, off-board computer controls (but not a central console), and a $20/ft2 building cost for a 25-high building.