Release Time Scheduling in Cargo Delivery.

H. Yaman, O.E. Karasan, and B.Y. Kara. 2008.

Abstract: Inspired by a real life problem faced by one of the largest ground based cargo companies of Turkey, the current study introduces a new facet to the hub location literature. As a hub location problem, the release time scheduling for next day delivery seeks to select a specified number of centers from a fixed set of demand centers as hubs, to allocate each demand center to a hub, to decide on the release times of trucks from each demand center in such a way that the total cargo guaranteed to be delivered to every potential destination by the next day is as high as possible. The paper introduces integer programming models to solve this problem in the special cases when the cargo uniformly arrives to each demand center during the day and the more realistic pattern of when the cargo arrivals exhibit a piecewise linear form. Several classes of valid inequalities are proposed to strengthen the formulations. An assortment of extensive computational results show the computational viability of the strengthened models under realistic scenarios as well as the validity of the proposed problem in answering several interesting questions from the cargo sector's perspective.

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