初步研究神经网络模型的构造方法，并利用多输入单输出切比雪夫神经网络模型建立世界干散海运量各年的海运量预测模型解决具体问题-preliminary study of the neural network model construction method, and the use of multiple-input single-output Chebyshev neural network model of the world's seaborne dry bulk quantities