An Improved Discrete PSO for Tugboat Assignment Problem under a Hybrid Scheduling Rule in Container Terminal

Su Wang,Min Zhu,Guoyue Chen,Mingya Wang,Ikou Kaku

doi:10.1155/2014/714832

Abstract

In container terminal, tugboat plays vital role in safety of ship docking. Tugboat assignment problem under a hybrid scheduling rule (TAP-HSR) is to determine the assignment between multiple tugboats and ships and the scheduling sequence of ships to minimize the turnaround time of ships. A mixed-integer programming model and the scheduling method are described for TAP-HSR problem. Then an improved discrete PSO (IDPSO) algorithm for TAP-HSR problem is proposed to minimize the turnaround time of ships. In particular, some new redefined PSO operators and the discrete updating rules of position and velocity are developed. The experimental results show that the proposed IDPSO can get better solutions than GA and basic discrete PSO.

Highlights

Nowadays, more and more people have recognized the importance of world trade via container terminals
We present the computational experiments to evaluate the performance of the improved discrete particle swarm optimization (PSO) algorithm in this paper
It can be seen that when the max iteration is fixed, the optimal solution is improved with the growth of swarm size because more particles have stronger space search capabilities

Summary

Introduction

More and more people have recognized the importance of world trade via container terminals. Only with an available berth and proper tugboats, a ship can dock safely and prepare for unloading or loading operation Otherwise, it has to wait at the anchorage outside the container terminal. Liu and Wang introduced tugboat allocation simulation [13] and Liu studied the tugboat scheduling problem and employed a hybrid evolutionary algorithm to solve this problem [14]. We introduce the tugboat assignment problem under a hybrid scheduling rule (TAP-HSR) and give the mathematical model. An improved discrete PSO algorithm for TAP-HSR problem is proposed to minimize the turnaround time of ships. Tugboat assignment problem under a hybrid scheduling rule (TAP-HSR) and the mathematical model are described.

Problem Formulation and Scheduling Rules

Discrete PSO Algorithm for TAP-HSR Problem

M1 40 min

Operators Redefinition

Experimental Results

Conclusions