The Port Tugboat Scheduling Optimization Based On Evolutionary Strategy Algorithm

Port which own equipment and conditions of water-land shipment is the transportation hub of providing ship safety in and out. With the global economic recovery, the development of the port is becoming an critical part of rapid economic growth in China. Port development is still in the stage of profit, profit maximization is the request of national strategy development. Hence, the profit maximization as the premise, how to improve the port service capability and management skills will become a key of modern port development. Tugboat operation is the "first" in the port production. Reasonable tugboat deployment will reduce cost and improve the efficiency of port operation so that it will provide the best guarantee for port logistical system.In the actual tugboat operation, the port tugboat operation scheduling optimization depend on how to save production cost and how to improve the use efficiency of tugboat. However, production cost and production efficiency are two contradictory factors. In the same production task, if using the small horsepower tugboat, unit-time production cost is lower than large horsepower tugboat, but the tugboat operation cycle is long so that the production efficiency is low. On the contrary, if using the large horsepower tugboat, unit-time production cost is higher than small horsepower tugboat, but the tugboat operation cycle is short so that the production efficiency will improve. Therefore, in the tugboat operation scheduling process, we shouldn’t simply consider the inverse relationship between production cost and production efficiency, but try to analyze deeply the complex relationship of two influence factors. Thereby giving a reasonable solution to optimize tugboat operation.Meanwhile, in the tugboat operation scheduling, considering the captain of the in and out of ship is random, and the number of tugboat and the horsepower need to match demands.As a consequence, according to the actual situation of Dayaowan operational zone in Dalian port, combined with the tugboat scheduling data from Dalian harbour tug&barge corporation, based on the parallel task scheduling theory with special process constraint, in order to reach the minimized aim of improving production efficiency and saving production cost. The article will apply with the modeling analysis approach to solving tugboat operation scheduling issues. On the basis of this, design of hybrid algorithms, combined with evolutionary strategy algorithm and local search algorithm, and evolutionary strategy algorithm of coding and decoding, recombination operator and mutation operator can be designed.Hybrid algorithm are designed to meet the process constraints. In the actual tugboat operation process, we can adjust the weight ratio of the production efficiency and production cost so that we can get the reasonable scheduling solution. Finally, though the optimum solution compared with simulation calculation results verify the validity and practicability of the hybrid algorithm.Therefore, in the actual production operation, using the hybrid algorithm to optimize tugboat operation, it is essential and significant.