Extensive research has been performed in the area of order
picking system design and operation. Rouwenhorst et al. (2000)
discussed order picking design and control problems in terms of
long, medium, and short term decisions such as sorting systems
for long term, layout, equipment and workforce capacity for medium
term, and workforce assignment for short term. In the situation
where the probability of visiting every aisle for one or more
picks is close to 1.0, traversal routing policy is close to optimal under
randomized storage policy