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Mathematical Problems in Engineering
Volume 2012 (2012), Article ID 246978, 22 pages
http://dx.doi.org/10.1155/2012/246978
Research Article

Simulated Annealing-Based Ant Colony Algorithm for Tugboat Scheduling Optimization

1Transportation Management College, Dalian Maritime University, Dalian 116026, China
2Dalian China Railway International Container Ltd., Dalian 116004, China

Received 5 September 2012; Accepted 23 September 2012

Academic Editor: Rui Mu

Copyright © 2012 Qi Xu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

As the “first service station” for ships in the whole port logistics system, the tugboat operation system is one of the most important systems in port logistics. This paper formulated the tugboat scheduling problem as a multiprocessor task scheduling problem (MTSP) after analyzing the characteristics of tugboat operation. The model considers factors of multianchorage bases, different operation modes, and three stages of operations (berthing/shifting-berth/unberthing). The objective is to minimize the total operation times for all tugboats in a port. A hybrid simulated annealing-based ant colony algorithm is proposed to solve the addressed problem. By the numerical experiments without the shifting-berth operation, the effectiveness was verified, and the fact that more effective sailing may be possible if tugboats return to the anchorage base timely was pointed out; by the experiments with the shifting-berth operation, one can see that the objective is most sensitive to the proportion of the shifting-berth operation, influenced slightly by the tugboat deployment scheme, and not sensitive to the handling operation times.