OPTIMIZATION OF CUBE-PER-ORDER INDEX WAREHOUSE LAYOUTS WITH ZONING CONSTRAINTS

Zoning constraints impose co-location of the storage addresses assigne d to individual items within the same storage area of a warehouse. The cube-per-order index (COI) rule for assigning items to locations cann ot guarantee orderpicking cost minimization when zoning constraints ar e active. A heuristic procedure is presented for using the COI to gene rate an initial item assignment followed by an improvement step. The i mprovement step includes a random search phase followed by a simulated annealing step designed to avoid trapping at local minima. The proced ure is illustrated in the context of a sample problem with 100 items s tored in a facility with 1600 storage addresses distributed among 25 z ones. Computational experimentation aimed at developing approximate gu idelines for controlling the improvement step are reported.