Robust Optimization Model for Resource Allocation of Container Shipping Lines

The operating efficiency of container shipping lines depends on proper resource allocation of container shipping.A deterministic model was developed for shipping lines based on the equilibrium principle.The objective was to optimize the resource allocation for container lines considering ship size,container deployment,and slot allocation.The deterministic model was then expanded to a robust optimization model accounting for the uncertain factors,while ship size was treated as the design variable and slot allocation as the control variable.The effectiveness of the proposed model is demonstrated using a pendulum shipping line as an example.The results indicate that infeasible solutions will increase and the model robustness will be enhanced by an increased penalty coefficient and the solution robustness will be enhanced by increasing the preference coefficient.The optimization model simultaneously considers demand uncertainty,model robustness,and risk preference of the decision maker to agree better with actual practices.

Key Technologies of the Hydraulic Structures of the Three Gorges Project

To date,the Three Gorges Project is the largest hydro junction in the world.It is the key project for the integrated water resource management and development of the Changjiang River.The technology of the project,with its huge scale and comprehensive benefits,is extremely complicated,and the design difficulty is greater than that of any other hydro project in the world.A series of new design theories and methods have been proposed and applied in the design and research process.Many key technological problems regarding hydraulic structures have been overcome,such as a gravity dam with multi-layer large discharge orifices,a hydropower station of giant generating units,and a giant continual multi-step ship lock with a high water head.

The Impact of Optimizing Trim on Reducing Fuel Consumption

The shipping industry is one of the biggest industries throughout the ages. Maritime transport plays a vital role in world economy; whereas competition between maritime companies is fierce [1], at the same time agreements of co-operation have taken different forms including alliances and mergers between companies to increase their market share. But competitions still stand despite all alliances even in same market. This intense competition drives companies to attain high level of competitiveness, by monitoring ship＇s operating performance and operating cost, emphasis on improving performance and reduce cost. On other hand new environmental regulations come to light, expansion of ECA （emission control areas）, which lead to significant higher fuel cost when using low sulfur fuel. Since the fuel cost is the largest portion of the operating cost of the vessel, a saving in fuel usage can result in considerable saving in operational costs. Furthermore, fuel saving has environmental benefits in the reduction of greenhouse gas emissions. The aim of this paper is to investigate the role of trim optimization which considers one of the easiest and cheapest methods for ship performance optimization and fuel consumption reduction trim optimization.

Receiving response of towed line array to the noise of the tow ship in shallow water

The receiving response of towed line array to the noise radiated from the tow ship is investigated through normal mode modeling and computer simulation. The phenomenon that the maximum output of the towed line array is away from the endfire direction towards the tow ship is explained. The result is important for the understanding of the phenomenon and also for the application research concerning the suppression of the noise from the tow ship as well as adequate application of towed array techniques in shallow water.