基于海洋气象信息的邻域自适应航速预测模型

Ship Speed Prediction Model Based on Domain Adaptation Using Ocean Meteorological Information

  • 摘要: 船舶在远洋航行时受通信带宽限制,船舶主机转速、吃水深度等船舶航行信息的获取有失真、缺失情况,造成岸端对在航船舶航速预测的不确定性,也给船舶带来安全隐患。为了在贫信息下预测不同海况下的船舶速度,选取2021年4月—2024年6月中国—东南亚航线航行的87条远洋散货船1101个航次,共计1.45×106样本量,建立基于海洋气象信息驱动的船舶航速预测模型。考虑到各航次间存在气象状况差异会导致数据驱动模型的泛化能力不足,采用邻域自适应(domain adaptation,DA)算法对训练数据进行特性空间优化,使训练集与测试集的数据分布特征趋于一致,确保模型在测试数据集同样具有鲁棒性。将DA算法结合LightGBM(light gradient boosting machine)建立模型DA-LightGBM并通过独立测试,预测结果表明:基于DA-LightGBM模型航速预测结果的均方根误差较传统经验方程降低42%,较LightGBM模型降低13.8%,有助于更好地满足船舶航速预测需求,提升船舶航行服务保障能力。

     

    Abstract: Due to the limitation of communication bandwidth, the acquisition of ship navigation information such as main engine speed and draft is distorted and missing, which often leads to the uncertainty of ship speed prediction at shore end, and also brings potential safety hazards to the ship. In order to predict ship speed under different sea conditions with poor information, in-depth investigation is conducted on 1101 voyages of 87 ocean bulk carriers sailing on China-Southeast Asia route, including a total of 1.45 million samples. A ship speed prediction model is established driven by marine meteorological information. Considering that the difference of meteorological conditions between different voyages will lead to the lack of generalization ability of the data-driven model, a representative method is used in the field of transfer learning domain adaptation (DA) to optimize the characteristic space of training data, so that distribution characteristics of meteorological data in the training set and the test set tend to be consistent, ensuring that the training model is also robust on new test data. DA method is integrated with LightGBM to develop the training model and conduct the independent test. 50-route closest to the departure time of the voyage are selected as the test set. Prediction results indicate that the mean of error absolute value between the speed predicted by LightGBM model and AIS speed is 0.47, and the root mean square error is 0.65, which increases by 32.85% and 30.53% respectively compared with prediction results of empirical equation. The mean of error absolute value between the speed predicted by DA-LightGBM method and AIS speed is 0.42, while the root mean square error is 0.56. These values represent increases of 10.63% and 13.85%, respectively, when compared to the speeds predicted by the LightGBM model. Additionally, determination coefficient is improved to 0.82. The sample deviation of the speed predicted by DA-LightGBM is nearly 70% lower than 0.5 knots. From the perspective of geographical waters, in narrow waterways, islands and waypoints close to land waters, DA-LightGBM compared with LightGBM, speed predictions of 3 methods have significant deviations in the waters around Taiwan Island, Hainan Island, the Strait of Malacca and the eastern Philippines. The significant deviation does not preclude the use of motorized navigation near the reef islands. DA-LightGBM demonstrates superior model interpretability and predictive speed, effectively meeting demands of ship speed prediction, and it enhances the capabilities of ship navigation service support.

     

/

返回文章
返回