| Ship dispatching is an important part of the operations of shipyards. Ship dispatching optimization will directly affect work efficiency, quality and costs, and thus the profitability of the shipping enterprises. With the development of the ship repairing and building industry, as well as the increasing number of berthed ships in the shipyard docks, and their diversity, the work load increases day by day. Due to the limited number of berths, when each berth contains several ships, the ship close to the dock will enjoy the optimum hoisting operation range. This thus requires constant shifting of berths so that each ship is able to use the hoisting equipment alternately, satisfying the engineering requirements of each ship. The traditional experiencebased ship shifting method cannot meet the production demand gradually. In order to improve the production efficiency, reduce production costs, and decrease work load, it is urgent to provide a new solution for this issue.Through study of ship repairing and shifting operations, this paper, based on the characteristics of the ship shifting and dispatching system of the shipyard, analyzes and optimizes the system. With systematic analysis throughout the paper, it establishes a mathematical optimization model and conducts system simulation and application. Finally, the paper carries out overall design of the ship shifting and dispatching system of the shipyard.1. Berth assignment system optimization(1) The paper analyzes the research status of the ship dispatching issue for the shipyards, and defines the ship shifting and dispatching system of shipyard, and thus proposes a two-phase ship shifting and dispatching system. The issue of ship shifting and dispatching at the shipyard is a dynamic production process that involves multiple stages and factors which interact and influence each other. Based on this feature, this paper analyzes the system and constructs the ship shifting and dispatching system model based on queuing theory, as well as puts forward system optimization theory with limited capacity.(2) The paper studies the core content of the ship shifting and dispatching issue, and simulates the manual ship shifting procedures. With reasonable use of ship dispatching rules, the paper sets up the multiple-target equilibrium mathematical simulation model for ship berth allocation, in the precondition of ensuring the shortest waiting time for ships, as well as the shortest time staying in the yard and the shortest berth shifting distance. The experience of dispatching personnel is integrated into the model. Various boundary conditions are defined.(3) Based on the multiple-target algorithm, multiple-target equilibrium algorithm combined with heuristic rules is set up. After solving the model, the manual and simulation solutions are compared through calculation examples, so as to verify the effectiveness, accuracy and superiority of the method.(4) Through analysis of the production characteristics of shipyard, the paper explores the influences of uncertain factors on the yard and the problem-solving methods of the system. Based on the multiple-target equilibrium berth allocation model, the paper establishes the berth dispatching interference management model for the shipyard. The effectiveness of the method is verified through calculation examples.2. Berth adjustment system optimizationAfter analysis of the ship shifting action and the ship status, the ship berth shifting issue in the shipyard is transformed to time discrete problem. Its system performance is argued. Cellular automation decision-making model is established. And network diagram is utilized to find the optimized path.3. The system overall designThe paper solves the demand of the ship repairing enterprises. It conducts overall design of the ship shifting and dispatching system for the shipyard. Moreover, Matlab is adopted to demonstrate some critical function interfaces. |
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