Ship Weather Routing Based on Hybrid Genetic Algorithm Under Complicated Sea Conditions

Considering the effects of increased economic globalization and global warming,developing methods for reducing shipping costs and greenhouse gas emissions in ocean transportation has become crucial.Owing to its key role in modern navigation technology,ship weather routing is the research focus of several scholars in this field.This study presents a hybrid genetic algorithm for the design of an optimal ship route for safe transoceanic navigation under complicated sea conditions.On the basis of the basic genetic algorithm,simulated annealing algorithm is introduced to enhance its local search ability and avoid premature convergence,with the ship’s voyage time and fuel consumption as optimization goals.Then,a mathematical model of ship weather routing is developed based on the grid system.A measure of fitness calibration is proposed,which can change the selection pressure of the algorithm as the population evolves.In addition,a hybrid crossover operator is proposed to enhance the ability to find the optimal solution and accelerate the convergence speed of the algorithm.Finally,a multi-population technique is applied to improve the robustness of the algorithm using different evolutionary strategies.

Development Experience of Foreign Green Shipping and Its Enlightenment to China

Based on analysis of green shipping practices of foreign ships manufacturers, ocean carriers ad port countries, their advanced experience was summarized, and its enlightenment to China＇s ＂green shipping＂ was analyzed to realize China＇s dream of becoming ＂ a strong shipping country＂ eady.

Hydraulic Geometry Relation for Navigable Canals Considering Ship Speed

Definition of hydraulic geometry of navigable canals and its expression are studied in this paper.The hydrodynamic and morphologic characteristics of navigable canals are analyzed on the basis of the data collected from field surveys conducted at two segments of the Grand Canal in Jiangsu Province,China.The channel morphologic factor and the ship hydrodynamic factor are adopted to describe the hydraulic geometry relation of navigable canals.The correlation analysis shows that the ship hydrodynamics can be a dominant factor influencing the channel evolution with larger determination coefficient.Furthermore,the undetermined index in the proposed hydraulic geometry relation is also discussed,which indicates that the index related to the intensity of water flow(qualitatively reflected by the integrated ship flow intensity)is within a range of 0.5 to 1.0.

A STUDY ON THE LOW SPEED SHIP THEORY

Based on Baba's assumption,the linearized free-surface boundary conditions at low speed are discussed in order to demonstrate the differences between Baba's and Dawson's free-surface boundary conditions.By using Fourier integral transfor- mation,a method of computing wave velocity potential ,which satisfies the boundary conditions of free-surface and hull surface,is presented.The solution of is found with the powerful technique of asymptotic expansions.With order comparison method,it is found that the hull surface boundary conditions can be neglected when only the ship wave resistance is concerned.The exact analytical solution of two-dimensional slow ship wave velocity potential is derived by neg- lecting hull effect.The results show that the inhomogeneous effect of free-surface is not negligible in the boundary value problems of slow ship velocity potential.

COMPARISON OF RESISTANCE FOR SEVERAL DISPLACEMENT HIGH PERFORMANCE VEHICLES

According to the linear wave resistance theory, a comparison among the ship resistance for the high speed round bilge ships, the deep “Vee” vessels, the wave-piercing catamarans, and the high speed trimarans was given by using the high-speed round-bilge ship as a benchmark. And the optimal speed range of each ship form was also suggested by using the analysis of the research results.

Machine Learning-Based Approach to Liner Shipping Schedule Design

This paper studied a tactical liner shipping schedule design issue under sail and port time uncertainties,which is the determination of the planned arrival time at each port call as well as the punctuality rate and number of assigned ship on the route.A number of studies have tried to introduce the operational speed adjustment measure into this tactical schedule design issue,to alleviate the discrepancies between designed schedule and maritime practice.On the one hand,weather conditions can lead to speed loss phenomenon of ships,which may result in the failure of ships’punctual arrivals.On the other hand,improving the ability of speed adjustment can decrease the late-arrival compensation,but increase the fuel consumption cost.Then,we formulated a machine learning-based liner shipping schedule design model aiming at above-mentioned two limitations on speed adjustment measure.And a machine learning-based approach has been designed,where the speed adjustment simulation,the neural network training and the reinforcement learning were included.Numerical experiments were conducted to validate our results and derive managerial insights,and then the applicability of machine learning method in shipping optimization issue has been confirmed.