Release Time Scheduling and Hub Location for Next-Day Delivery

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. The release time scheduling and hub location problem aims to select a specified number of hubs from a fixed set of demand centers, to allocate each demand center to a hub, and to decide on the release times of trucks from each demand center in such a way that the total amount of cargo guaranteed to be delivered to every potential destination by the next day is not below a threshold and the total routing cost is minimized. 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. Extensions with multiple service levels and discrete sets for release times are also discussed. Computational results show the computational viability of the models under realistic scenarios as well as the validity of the proposed problems in answering several interesting questions from the cargo sector's perspective.

Routing and scheduling decisions in the hierarchical hub location problem

“…In Kara and Tansel (2001) , the authors emphasize the importance of synchronization in cargo delivery systems. Later, Yaman et al (2012) combine the release time scheduling and hub location problems in cargo delivery applications.…”

Multimodal hub location and hub network design

“…However, they can easily be extended to the feasible region of (P0). The methodology borrows ideas from Yaman et al [45]. The proofs of the validity of all the inequalities are presented in the Appendix.…”

“…Campbell [10] is the first study minimizing transportation costs subject to a constraint on the service level in hub location problems. A follow up study by Yaman et al [45] also addresses this issue and proposes models incorporating transportation costs and service levels for complete hub networks.…”

“…For example, most of the less-than truckload firms offer different delivery schedules for their customers such as overnight delivery and second day delivery, for different origindestination pairs. This issue has been considered in Yaman et al [45], and Ishfaq and Sox [26,27] only for complete hub networks.…”

Star p-hub center problem and star p-hub median problem with bounded path lengths

“…See, for instance, Alumur et al [2], Campbell [4], Yaman [40,41], Yaman et al [42,43]. Our second problem SpHMP-BP belongs to this class and has features of both the p-hub median problem and the hub covering problem.…”