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Dynamically scheduling ships to multiple continuous berth spaces in an iron and steel complex
Author(s) -
Tang Lixin,
Li Shaohua,
Liu Jiyin
Publication year - 2009
Publication title -
international transactions in operational research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.032
H-Index - 52
eISSN - 1475-3995
pISSN - 0969-6016
DOI - 10.1111/j.1475-3995.2009.00662.x
Subject(s) - lagrangian relaxation , mathematical optimization , computation , scheduling (production processes) , computer science , job shop scheduling , lagrangian , lagrange multiplier , algorithm , mathematics , routing (electronic design automation) , computer network
This paper studies the problem of dynamically scheduling ships to multiple continuous berth spaces at the raw material docks in an iron and steel complex with the objective of minimizing the total weighted service time. We propose two mathematical models and develop an improved Lagrangian relaxation algorithm to solve the problem. Based on the problem structure, six properties are observed that help speed up the procedures of solving the sub‐problems, updating Lagrangian multipliers and obtaining feasible solutions, respectively. Computational results on 50 real data problems and 120 randomly generated problems show that the algorithm generates good solutions in short time and that using the properties can reduce by more than 80% the computation time of the algorithm.