Scheduling of inbound and outbound trucks in cross docking systems with temporary storage

The technique of cross-docking, which consists in unloading trucks, sorting the items they contain and reloading them directly into outbound trucks in order to minimize temporary storage, has attracted researchers׳ attention in the past few years. The number of articles on the subject has been growing very fast, but largely detached from industry practice. In order to see whether the current state-of-the-art matches the industry practice, we propose a common framework that helps comparing the literature review regarding cross-docking operations with on-field observations and platform managers׳ interviews. Analyzing the gaps between the state-of-the-art and the industry practice helps drawing future research directions, in relation to industrial needs.

Cross-docking operations: Current research versus industry practice

Cross-docking is an approach in inventory management which can reduce inventories, lead times and customer response time. In this strategy, products and shipments are unloaded from inbound trucks, sorted and categorized based on their characteristics, moved and loaded onto outbound trucks for delivery to demand points in a distribution network. The important fact is that, the items are stored in the inventory for a period which is primarily less than the actual time allocated to keep these items in a typical warehouse. Therefore, total cost and space requirement for inventory can be cut down. One of the most important targets in such systems is to establish coordination between the performance of inbound and outbound trucks in that these trucks can be scheduled, and the product items can be allocated to trucks effectively. This paper addresses some meta-heuristics to find the best sequence of inbound and outbound trucks, so that the objective, minimizing the total operation time called makespan, can be satisfied. Furthermore, not only the efficiency and capability of the algorithms' parameters are assessed and analyzed by some performance measures, but also these meta-heuristics are compared with each other in order to find out the set of homogeneous algorithms among all proposed algorithms. By this analysis, it can be shown that the suitability of these meta-heuristics is quite sensible especially for the cross-docking systems with large sizes in which a high volume of inbound or outbound trucks transmit the product items.

Meta-heuristics implementation for scheduling of trucks in a cross-docking system with temporary storage

In a cross-docking system, trucks must be scheduled to minimize the total flow time of the system. This problem is NP-hard, and this study proposes two hybrid meta-heuristics—hybrid simulated annealing and hybrid variable neighborhood search—to solve it by achieving the best sequence of truck pairs. The Taguchi method serves to reveal the best robustness of these algorithms. To demonstrate the effectiveness of the proposed methods, especially for large-sized problems, this study solves various test problems, and the computational results clearly reveal that the proposed methods outperform previous approaches.

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Scheduling Trucks In Cross-Docking Systems: A Robust Meta-Heuristics Approach

This paper addresses a scheduling problem of inbound and outbound trailers in a cross-docking system according to just-in-time approach. In the cross-docking system, commodities are unloaded from inbound trailers, sorted and categorized based on their specifications and loaded onto outbound trailers for delivery to demand points in a distribution network. One of the most fundamental issues in such systems is to establish coordination between the performance of inbound and outbound trailers in that they can be scheduled, and the product items can be assigned to trailers effectively. As we observe the JIT concept, the punctuality and exactness of product deliveries are vital for the system’s performance. To satisfy this target, this paper considers a multi-criteria scheduling in which primary objective is to minimize earliness and tardiness simultaneously via a unified objective function. Three meta-heuristics are applied for this matter, and their solutions’ quality and the acquired elapsed time are compared with each other in each case.

A multi-criteria cross-docking scheduling with just-in-time approach

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1412&context=rtd

Wooyeon Yu

Papers

Operational strategies for cross docking systems