Logistics scheduling with batching and transportation

This paper studies a general two-stage scheduling problem, in which jobs of different importance are processed by one first-stage processor and then, in the second stage, the completed jobs need to be batch delivered to various pre-specified destinations in one of a number of available transportation modes. Our objective is to minimize the sum of weighted job delivery time and total transportation cost. Since this problem involves not only the traditional performance measurement, such as weighted completion time, but also transportation arrangement and cost, key factors in logistics management, we thus call this problem logistics scheduling with batching and transportation (LSBT) problem. We draw an overall picture of the problem complexity for various cases of problem parameters accompanied by polynomial algorithms for solvable cases. On the other hand, we provide for the most general case an approximation algorithm of performance guarantee. 2007 Elsevier B.V. All rights reserved.