Pub Date : 2026-02-01DOI: 10.1016/j.joes.2025.11.007
Pinzheng Hu , Bo Ai , Haolin Cai , Zhen Wen , Wenjun Feng , Chongjun Feng , Xue Liu , Guannan Lv
Monitoring and predicting marine environmental variables are important for safeguarding livelihoods and the economy. Large language models (LLMs) have shown great potential in time series prediction because of their strong computational capabilities, and the application of LLMs to the prediction of marine environmental variables is an emerging area of research. However, LLM-based approaches often exhibit oscillations in prediction outputs and large deviations from observed values. To address these issues, we propose TimeLLM-BERT, a hybrid three-stage model based on feature extraction, autoregressive prediction, and error correction. The model incorporates a structured prompt module, a trend enhancement algorithm, and a residual-fitting optimization strategy, which significantly enhance prediction accuracy. To systematically evaluate the performance of the model, comparative experiments were conducted against LSTM, BiTCN, NBEATSx, iTransformer, NHITS, and Time-LLM models using four key variables: significant wave height (SWH), sea surface temperature (SST), temperature at 2 m above the sea surface (T2M), and wind field (WF). The results show that the performance of the model is significantly better than existing models, and the mean absolute error for SWH prediction is reduced by 24.7%. It also achieves stable performance in SST prediction and strong consistency in WF prediction compared with the existing models. Robustness and universality tests show that the error evaluation indicators exhibit low variation, demonstrating strong stability and generalization ability. In summary, TimeLLM-BERT offers significant improvements in accuracy and stability for predicting marine environmental variables, providing a new framework for modeling complex time series data.
监测和预测海洋环境变量对于保障生计和经济至关重要。大型语言模型(Large language models, llm)由于其强大的计算能力在时间序列预测中显示出巨大的潜力,将llm应用于海洋环境变量的预测是一个新兴的研究领域。然而,基于llm的方法在预测输出中经常出现振荡,并且与观测值存在较大偏差。为了解决这些问题,我们提出了TimeLLM-BERT,这是一种基于特征提取、自回归预测和误差校正的混合三阶段模型。该模型结合结构化提示模块、趋势增强算法和残差拟合优化策略,显著提高了预测精度。为了系统地评价模型的性能,利用有效波高(SWH)、海面温度(SST)、海面以上2 m温度(T2M)和风场(WF) 4个关键变量,与LSTM、BiTCN、NBEATSx、iTransformer、NHITS和Time-LLM模型进行了对比实验。结果表明,该模型的性能明显优于现有模型,SWH预测的平均绝对误差降低了24.7%。与现有模型相比,该模型在预测海表温度方面具有稳定的性能,在预测WF方面具有较强的一致性。鲁棒性和通用性检验表明,误差评价指标具有较低的变异性,具有较强的稳定性和泛化能力。综上所述,TimeLLM-BERT在预测海洋环境变量的准确性和稳定性方面有了显著提高,为复杂时间序列数据的建模提供了一个新的框架。
{"title":"Large language models for the marine environmental variables prediction","authors":"Pinzheng Hu , Bo Ai , Haolin Cai , Zhen Wen , Wenjun Feng , Chongjun Feng , Xue Liu , Guannan Lv","doi":"10.1016/j.joes.2025.11.007","DOIUrl":"10.1016/j.joes.2025.11.007","url":null,"abstract":"<div><div>Monitoring and predicting marine environmental variables are important for safeguarding livelihoods and the economy. Large language models (LLMs) have shown great potential in time series prediction because of their strong computational capabilities, and the application of LLMs to the prediction of marine environmental variables is an emerging area of research. However, LLM-based approaches often exhibit oscillations in prediction outputs and large deviations from observed values. To address these issues, we propose TimeLLM-BERT, a hybrid three-stage model based on feature extraction, autoregressive prediction, and error correction. The model incorporates a structured prompt module, a trend enhancement algorithm, and a residual-fitting optimization strategy, which significantly enhance prediction accuracy. To systematically evaluate the performance of the model, comparative experiments were conducted against LSTM, BiTCN, NBEATSx, iTransformer, NHITS, and Time-LLM models using four key variables: significant wave height (SWH), sea surface temperature (SST), temperature at 2 m above the sea surface (T2M), and wind field (WF). The results show that the performance of the model is significantly better than existing models, and the mean absolute error for SWH prediction is reduced by 24.7%. It also achieves stable performance in SST prediction and strong consistency in WF prediction compared with the existing models. Robustness and universality tests show that the error evaluation indicators exhibit low variation, demonstrating strong stability and generalization ability. In summary, TimeLLM-BERT offers significant improvements in accuracy and stability for predicting marine environmental variables, providing a new framework for modeling complex time series data.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"11 1","pages":"Pages 204-221"},"PeriodicalIF":11.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.joes.2025.09.003
Shuangshuang Fan , Peng Yuan , Jiacheng Feng , Huijun Huang , Sheng Hu , Zhongkuo Zhao , Yu Zhu , Kai Wang
Accurate and persistent observation of typhoon-induced upper ocean dynamics remains challenging due to strong currents and the limited station-keeping capability of autonomous platforms. This study proposes a learning-based virtual mooring framework using an underwater glider array to observe typhoon-driven processes in the South China Sea. A deep reinforcement learning approach based on the Dueling Double Deep Q-Network (D3QN) architecture is developed to improve station-keeping under dynamic flows and forecast uncertainties. Simulations involving 840,000 dive profiles across 400 sites show that the D3QN method achieves the lowest average station-keeping error (0.68 km), outperforming reactive and predictive strategies. Robustness tests confirm reliable performance under perturbed forecasts. Field experiments during typhoon conditions further demonstrate the feasibility of glider-based virtual mooring, and glider observations reveal pronounced upper-ocean responses, highlighting the framework’s utility for capturing typhoon-induced variability.
{"title":"Observing typhoon-driven upper ocean dynamics in the South China Sea using a virtual mooring underwater glider array: Methods and analysis","authors":"Shuangshuang Fan , Peng Yuan , Jiacheng Feng , Huijun Huang , Sheng Hu , Zhongkuo Zhao , Yu Zhu , Kai Wang","doi":"10.1016/j.joes.2025.09.003","DOIUrl":"10.1016/j.joes.2025.09.003","url":null,"abstract":"<div><div>Accurate and persistent observation of typhoon-induced upper ocean dynamics remains challenging due to strong currents and the limited station-keeping capability of autonomous platforms. This study proposes a learning-based virtual mooring framework using an underwater glider array to observe typhoon-driven processes in the South China Sea. A deep reinforcement learning approach based on the Dueling Double Deep Q-Network (D3QN) architecture is developed to improve station-keeping under dynamic flows and forecast uncertainties. Simulations involving 840,000 dive profiles across 400 sites show that the D3QN method achieves the lowest average station-keeping error (0.68 km), outperforming reactive and predictive strategies. Robustness tests confirm reliable performance under perturbed forecasts. Field experiments during typhoon conditions further demonstrate the feasibility of glider-based virtual mooring, and glider observations reveal pronounced upper-ocean responses, highlighting the framework’s utility for capturing typhoon-induced variability.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"11 1","pages":"Pages 33-57"},"PeriodicalIF":11.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.joes.2025.09.004
Ruba Zaheer , Quoc Viet Phung , Iftekhar Ahmad , Asma Aziz , Daryoush Habibi , Yue Rong , Walid K Hasan
This paper comprehensively reviews recent advancements in Underwater Beamforming (UWB) systems, highlighting its pivotal role in underwater communication, sensing, and environmental monitoring. It explores the various beamforming applications, ranging from maritime surveillance to marine life monitoring, and indicates its significance in enhancing signal clarity, spatial resolution, and noise suppression in underwater acoustic environments. The unique challenges posed by the underwater environment that introduce complexities into the beamforming process such as non-stationary noise interference, severe signal attenuation, multipath propagation, and dynamic environmental variability are thoroughly discussed. The review systematically discusses and examines conventional, adaptive, and learning-based beamforming techniques, analyzing their strengths, limitations, and suitability for various underwater conditions. A detailed analysis of Direction of Arrival (DOA) estimation methods is provided. Furthermore, the review surveys the metrics commonly used to assess the performance of beamforming algorithms and compares their performance numerically. Emerging trends in beamforming, particularly the integration of data-driven machine learning approaches with traditional signal processing methods, are also discussed. The paper concludes by highlighting critical gaps in existing research and proposing future directions.
{"title":"A review on underwater beamforming: Techniques, challenges, and future directions","authors":"Ruba Zaheer , Quoc Viet Phung , Iftekhar Ahmad , Asma Aziz , Daryoush Habibi , Yue Rong , Walid K Hasan","doi":"10.1016/j.joes.2025.09.004","DOIUrl":"10.1016/j.joes.2025.09.004","url":null,"abstract":"<div><div>This paper comprehensively reviews recent advancements in Underwater Beamforming (UWB) systems, highlighting its pivotal role in underwater communication, sensing, and environmental monitoring. It explores the various beamforming applications, ranging from maritime surveillance to marine life monitoring, and indicates its significance in enhancing signal clarity, spatial resolution, and noise suppression in underwater acoustic environments. The unique challenges posed by the underwater environment that introduce complexities into the beamforming process such as non-stationary noise interference, severe signal attenuation, multipath propagation, and dynamic environmental variability are thoroughly discussed. The review systematically discusses and examines conventional, adaptive, and learning-based beamforming techniques, analyzing their strengths, limitations, and suitability for various underwater conditions. A detailed analysis of Direction of Arrival (DOA) estimation methods is provided. Furthermore, the review surveys the metrics commonly used to assess the performance of beamforming algorithms and compares their performance numerically. Emerging trends in beamforming, particularly the integration of data-driven machine learning approaches with traditional signal processing methods, are also discussed. The paper concludes by highlighting critical gaps in existing research and proposing future directions.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"11 1","pages":"Pages 58-77"},"PeriodicalIF":11.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.joes.2025.11.009
Shuang Shu , Wojciech Sumelka , Zhitao Ye , Yifei Sun , Fei Zhang
The sand-steel interface (SSI) behavior is crucial for the stability of offshore structures in marine environments. A series of cyclic and post-cyclic shear tests were conducted using a modified direct shear apparatus (MDSA), to examine both global and local SSI behaviors. Experimental visualization and image processing improvements enabled a comprehensive investigation of the influences of material properties and loading characteristics. Cyclic loading induced significant dilation-contraction alternations, with overall contraction predominating. Boundary conditions influenced the trends of cyclic shear stress, which stabilized after a specific loading cycles. Post-cyclic SSI exhibited notable dilation and stress-softening. Sands with improved gradation showed poor SSI strength development and more pronounced cyclic contraction. An optimal surface roughness for SSI strength development was identified. Dilation state lines, reflecting cyclic deformation, displayed a downward trend with progressive loading cycles. Friction angles, affected by displacement amplitude, underwent a weakening-strengthing-stabilizing process with cumulated shear displacement. Shear band thicknesses, sensitive to normal stress, surface roughness, and displacement amplitude, gradually stabilized with increased shear displacement. Grain microstructure evolution during cyclic shearing depended on the initial sand fabric. Fine grains migrated and collapsed during cyclic loading, combined with grains lying down, lubricating sand-sand friction. Insignificant macro-micro changes in SSI with a smooth plate indicated only sliding motion occurring.
{"title":"Global and local behaviors of sand-steel interfaces subjected to cyclic and post-cyclic shear loading","authors":"Shuang Shu , Wojciech Sumelka , Zhitao Ye , Yifei Sun , Fei Zhang","doi":"10.1016/j.joes.2025.11.009","DOIUrl":"10.1016/j.joes.2025.11.009","url":null,"abstract":"<div><div>The sand-steel interface (SSI) behavior is crucial for the stability of offshore structures in marine environments. A series of cyclic and post-cyclic shear tests were conducted using a modified direct shear apparatus (MDSA), to examine both global and local SSI behaviors. Experimental visualization and image processing improvements enabled a comprehensive investigation of the influences of material properties and loading characteristics. Cyclic loading induced significant dilation-contraction alternations, with overall contraction predominating. Boundary conditions influenced the trends of cyclic shear stress, which stabilized after a specific loading cycles. Post-cyclic SSI exhibited notable dilation and stress-softening. Sands with improved gradation showed poor SSI strength development and more pronounced cyclic contraction. An optimal surface roughness for SSI strength development was identified. Dilation state lines, reflecting cyclic deformation, displayed a downward trend with progressive loading cycles. Friction angles, affected by displacement amplitude, underwent a weakening-strengthing-stabilizing process with cumulated shear displacement. Shear band thicknesses, sensitive to normal stress, surface roughness, and displacement amplitude, gradually stabilized with increased shear displacement. Grain microstructure evolution during cyclic shearing depended on the initial sand fabric. Fine grains migrated and collapsed during cyclic loading, combined with grains lying down, lubricating sand-sand friction. Insignificant macro-micro changes in SSI with a smooth plate indicated only sliding motion occurring.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"11 1","pages":"Pages 238-256"},"PeriodicalIF":11.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.joes.2025.08.008
Md. Ekramul Islam , Md. Abde Mannaf , Mst. Tania Khatun , Md. Azizur Rahman , M. Ali Akbar , Udoy S. Basak
The simplified modified Camassa–Holm equation plays a pivotal role in modeling nonlinear wave dynamics across diverse fields, including optical fibers, biological transport, plasma physics, and shallow water flows. Its unique mathematical structure captures essential features of wave-breaking phenomena, peakon interactions, and dispersive effects that are crucial for understanding real-world wave behavior. Motivated by the need to predict extreme wave events and design efficient wave energy systems, this study investigates how external forces such as friction and wind influence wave dynamics. We explore rich dynamical transitions through a detailed bifurcation analysis. Our systematic investigation reveals critical thresholds in parameter space where small changes in forcing conditions lead to dramatic transformations in wave behavior. We identify key equilibrium states, nodes, foci, centres, and saddle points, that govern the system’s response, leading to the discovery of novel wave solutions, including kink-like waves, periodic structures, and breather-like solitons. These soliton shapes have potential applications in coastal protection, energy harvesting from waves, and signal modulation in nonlinear optical systems, highlighting their practical significance. These solutions are rigorously validated through numerical simulations and stability analysis, confirming their physical relevance across different parameter regimes. The solutions are derived in exact analytical forms using hyperbolic and trigonometric functions, revealing how parameter variations trigger qualitative shifts in wave patterns. Specifically, we demonstrate how the wind parameter controls wave amplification while the friction parameter governs energy dissipation, providing a complete picture of their competing effects on wave evolution. Our findings deepen the theoretical understanding of nonlinear waves while offering practical insights for coastal engineering, climate modeling, signal transmission, and wave energy systems. By explicitly linking solution families to potential engineering applications, this study provides a framework for designing devices that exploit specific soliton structures to achieve targeted wave control and energy efficiency. The methodology developed here can be readily extended to other nonlinear dispersive systems, opening new avenues for investigating wave-structure interactions in various physical contexts.
{"title":"Phase plane bifurcation analysis of water wave dynamics in the simplified modified Camassa–Holm model with friction and wind effects","authors":"Md. Ekramul Islam , Md. Abde Mannaf , Mst. Tania Khatun , Md. Azizur Rahman , M. Ali Akbar , Udoy S. Basak","doi":"10.1016/j.joes.2025.08.008","DOIUrl":"10.1016/j.joes.2025.08.008","url":null,"abstract":"<div><div>The simplified modified Camassa–Holm equation plays a pivotal role in modeling nonlinear wave dynamics across diverse fields, including optical fibers, biological transport, plasma physics, and shallow water flows. Its unique mathematical structure captures essential features of wave-breaking phenomena, peakon interactions, and dispersive effects that are crucial for understanding real-world wave behavior. Motivated by the need to predict extreme wave events and design efficient wave energy systems, this study investigates how external forces such as friction and wind influence wave dynamics. We explore rich dynamical transitions through a detailed bifurcation analysis. Our systematic investigation reveals critical thresholds in parameter space where small changes in forcing conditions lead to dramatic transformations in wave behavior. We identify key equilibrium states, nodes, foci, centres, and saddle points, that govern the system’s response, leading to the discovery of novel wave solutions, including kink-like waves, periodic structures, and breather-like solitons. These soliton shapes have potential applications in coastal protection, energy harvesting from waves, and signal modulation in nonlinear optical systems, highlighting their practical significance. These solutions are rigorously validated through numerical simulations and stability analysis, confirming their physical relevance across different parameter regimes. The solutions are derived in exact analytical forms using hyperbolic and trigonometric functions, revealing how parameter variations trigger qualitative shifts in wave patterns. Specifically, we demonstrate how the wind parameter <span><math><mi>α</mi></math></span> controls wave amplification while the friction parameter <span><math><mi>β</mi></math></span> governs energy dissipation, providing a complete picture of their competing effects on wave evolution. Our findings deepen the theoretical understanding of nonlinear waves while offering practical insights for coastal engineering, climate modeling, signal transmission, and wave energy systems. By explicitly linking solution families to potential engineering applications, this study provides a framework for designing devices that exploit specific soliton structures to achieve targeted wave control and energy efficiency. The methodology developed here can be readily extended to other nonlinear dispersive systems, opening new avenues for investigating wave-structure interactions in various physical contexts.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"11 1","pages":"Pages 1-12"},"PeriodicalIF":11.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.joes.2025.10.007
Murat Mert Tekeli , M. Fatih Gulen , Emre Akyuz , Ângelo P. Teixeira
Mooring operations are considered one of the most high-risk activities in cargo ship operations due to the complex interplay of human factors, equipment condition and environmental factors. This paper investigates quantitatively the mooring line risk during cargo operations in ships. To achieve this purpose, a robust practical approach integrating improved Z-numbers and a Bayesian network is proposed to perform probabilistic risk analysis. In the approach, whilst improved Z-numbers are employed to model uncertainty more effectively, considering both the probability of failure and the confidence in the data, the Bayesian network is used to analyse causal relationships and update risk assessments dynamically based on real-time operational data and environmental conditions. The proposed approach enhances predictive accuracy, enabling ship crews or technical ship inspectors to make informed decisions on mitigating risks under uncertain and variable conditions. The findings of the paper show that the mooring line failure probability during cargo operations is 0.015, and the root cause, “failure to adapt to tidal conditions”, is the main contributing factor. The proposed risk assessment approach provides valuable contributions for implementing proactive risk mitigation strategies and enhancing operational safety in cargo operations in maritime transportation.
{"title":"Improved hybrid Z-number Bayesian network approach to predict mooring line failure during cargo operations in ships","authors":"Murat Mert Tekeli , M. Fatih Gulen , Emre Akyuz , Ângelo P. Teixeira","doi":"10.1016/j.joes.2025.10.007","DOIUrl":"10.1016/j.joes.2025.10.007","url":null,"abstract":"<div><div>Mooring operations are considered one of the most high-risk activities in cargo ship operations due to the complex interplay of human factors, equipment condition and environmental factors. This paper investigates quantitatively the mooring line risk during cargo operations in ships. To achieve this purpose, a robust practical approach integrating improved Z-numbers and a Bayesian network is proposed to perform probabilistic risk analysis. In the approach, whilst improved Z-numbers are employed to model uncertainty more effectively, considering both the probability of failure and the confidence in the data, the Bayesian network is used to analyse causal relationships and update risk assessments dynamically based on real-time operational data and environmental conditions. The proposed approach enhances predictive accuracy, enabling ship crews or technical ship inspectors to make informed decisions on mitigating risks under uncertain and variable conditions. The findings of the paper show that the mooring line failure probability during cargo operations is 0.015, and the root cause, “failure to adapt to tidal conditions”, is the main contributing factor. The proposed risk assessment approach provides valuable contributions for implementing proactive risk mitigation strategies and enhancing operational safety in cargo operations in maritime transportation.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"11 1","pages":"Pages 141-153"},"PeriodicalIF":11.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.joes.2025.10.009
Jianwen Ma , Zhaojun Chen , Jingru Yuan , Jinyu Li , Guoxin Liu
Understanding and accurately predicting the trajectory changes of fishing ships is of great significance for effectively preventing collisions between merchant and fishing ships and enhancing the safety supervision of fishing ships. Due to the problems that the existing methods for predicting the trajectories of fishing ships are few and have low accuracy, and the spatiotemporal interaction information and the characteristics of companion navigation of fishing ships are not fully utilized, a Space-Time-Transformer (ST-Transformer) model considering the spatiotemporal interaction and companion navigation behavior characteristics of fishing ship trajectories is proposed. This model is based on the Transformer framework and considers the trajectory information of fishing ships under navigation conditions, and through stacking Graph Convolutional Networks (GCN), it mines the multi-layer spatial interaction with surrounding ships. Meanwhile, in order to increase the model's ability to capture the behavior characteristics of convoy navigation of fishing ships and improve the accuracy of fishing ship trajectory prediction, the concept of companion loss function is proposed, and the Fréchet distance is used to measure the similarity of fishing ship trajectories, to better quantify the dynamic spatial-temporal distance between fishing ships from an overall perspective. Through the evaluation and comparative analysis of different experimental scenarios and experimental methods, the ST-Transformer model has exhibited excellent accuracy, robustness, and generalization ability, and can achieve fishing ship trajectory prediction with relatively high precision.
{"title":"Fishing ship trajectory prediction considering trajectory behavior characteristics","authors":"Jianwen Ma , Zhaojun Chen , Jingru Yuan , Jinyu Li , Guoxin Liu","doi":"10.1016/j.joes.2025.10.009","DOIUrl":"10.1016/j.joes.2025.10.009","url":null,"abstract":"<div><div>Understanding and accurately predicting the trajectory changes of fishing ships is of great significance for effectively preventing collisions between merchant and fishing ships and enhancing the safety supervision of fishing ships. Due to the problems that the existing methods for predicting the trajectories of fishing ships are few and have low accuracy, and the spatiotemporal interaction information and the characteristics of companion navigation of fishing ships are not fully utilized, a Space-Time-Transformer (ST-Transformer) model considering the spatiotemporal interaction and companion navigation behavior characteristics of fishing ship trajectories is proposed. This model is based on the Transformer framework and considers the trajectory information of fishing ships under navigation conditions, and through stacking Graph Convolutional Networks (GCN), it mines the multi-layer spatial interaction with surrounding ships. Meanwhile, in order to increase the model's ability to capture the behavior characteristics of convoy navigation of fishing ships and improve the accuracy of fishing ship trajectory prediction, the concept of companion loss function is proposed, and the Fréchet distance is used to measure the similarity of fishing ship trajectories, to better quantify the dynamic spatial-temporal distance between fishing ships from an overall perspective. Through the evaluation and comparative analysis of different experimental scenarios and experimental methods, the ST-Transformer model has exhibited excellent accuracy, robustness, and generalization ability, and can achieve fishing ship trajectory prediction with relatively high precision.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"11 1","pages":"Pages 163-179"},"PeriodicalIF":11.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.joes.2025.09.002
Jialuan Xiao , Zida Shan , Junjun Cao , Yanjie Sun , Yang Cao , Xinguang Du , Baoheng Yao , Caoyang Yu , He Zhang
Hovering deep-sea mining provides a new direction for deep-sea nodule mining; however, accurate trajectory tracking of hovering mining vehicle remains a key challenge. This paper presents an adaptive RBF network sliding mode controller (ARBFNNSMC) for trajectory tracking of hovering mining vehicles. The ARBFNNSMC control loop features an RBF network to compensate for lumped external disturbance and system uncertainty, online adjustment of the RBF network parameters are achieved via adaptive laws derived based on Lyapunov function to guarantee closed-loop stability. In addition, a new type of smooth switching term is proposed on the basis of the plate-pole capacitor model for reduced chattering and adopted in ARBFNNSMC. To assess control performance and robustness, numerical simulations were performed based on three typical hovering mining trajectories. The simulation results demonstrate that the proposed controller achieved excellent robustness in all simulation cases, attaining reduced tracking error, overshoot, and settling time with improved chattering suppression in control output. Compared to conventional sliding mode controller, the mean RMS tracking error and settling time were 30.9% and 61.8% lower, respectively, while the thrust oscillation was reduced by 57.3%.
{"title":"Adaptive RBF network based sliding mode controller with novel switching term for hovering deep sea mining vehicle trajectory tracking","authors":"Jialuan Xiao , Zida Shan , Junjun Cao , Yanjie Sun , Yang Cao , Xinguang Du , Baoheng Yao , Caoyang Yu , He Zhang","doi":"10.1016/j.joes.2025.09.002","DOIUrl":"10.1016/j.joes.2025.09.002","url":null,"abstract":"<div><div>Hovering deep-sea mining provides a new direction for deep-sea nodule mining; however, accurate trajectory tracking of hovering mining vehicle remains a key challenge. This paper presents an adaptive RBF network sliding mode controller (ARBFNNSMC) for trajectory tracking of hovering mining vehicles. The ARBFNNSMC control loop features an RBF network to compensate for lumped external disturbance and system uncertainty, online adjustment of the RBF network parameters are achieved via adaptive laws derived based on Lyapunov function to guarantee closed-loop stability. In addition, a new type of smooth switching term is proposed on the basis of the plate-pole capacitor model for reduced chattering and adopted in ARBFNNSMC. To assess control performance and robustness, numerical simulations were performed based on three typical hovering mining trajectories. The simulation results demonstrate that the proposed controller achieved excellent robustness in all simulation cases, attaining reduced tracking error, overshoot, and settling time with improved chattering suppression in control output. Compared to conventional sliding mode controller, the mean RMS tracking error and settling time were 30.9% and 61.8% lower, respectively, while the thrust oscillation was reduced by 57.3%.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"11 1","pages":"Pages 13-32"},"PeriodicalIF":11.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.joes.2025.08.003
Changmin Pyo , Jaewoong Kim , Hyunseok Oh
Simulation models can be effectively used to predict welding distortion and residual stress in laser welding systems. To this end, developing a sophisticated heat source model for finite element analysis (FEA) is crucial. This study proposes a novel multi-layered heat source model for FEA to predict the melting zone of the welds in fiber laser welding. The proposed model has multiple degrees of freedom sufficient to simulate various heat sources. A systematic approach by solving inverse problems with global optimization is devised to estimate heat source model parameters. To achieve this, a simplified FEA model is incorporated to accelerate the simulation process. Experimental results using 9% nickel steel indicate that the proposed framework provides more accurate predictions on the melting zone of the welds than existing methods while reducing the computational cost by 1/2000. The proposed framework can be used by field engineers to find the relevant heat source subjected to on-site welding conditions, minimizing trials and errors. With this method, fast and accurate welding simulations can be performed, ultimately leading to improved productivity.
{"title":"Multi-layered heat source model for fiber laser welding of cryogenic steel","authors":"Changmin Pyo , Jaewoong Kim , Hyunseok Oh","doi":"10.1016/j.joes.2025.08.003","DOIUrl":"10.1016/j.joes.2025.08.003","url":null,"abstract":"<div><div>Simulation models can be effectively used to predict welding distortion and residual stress in laser welding systems. To this end, developing a sophisticated heat source model for finite element analysis (FEA) is crucial. This study proposes a novel multi-layered heat source model for FEA to predict the melting zone of the welds in fiber laser welding. The proposed model has multiple degrees of freedom sufficient to simulate various heat sources. A systematic approach by solving inverse problems with global optimization is devised to estimate heat source model parameters. To achieve this, a simplified FEA model is incorporated to accelerate the simulation process. Experimental results using 9% nickel steel indicate that the proposed framework provides more accurate predictions on the melting zone of the welds than existing methods while reducing the computational cost by 1/2000. The proposed framework can be used by field engineers to find the relevant heat source subjected to on-site welding conditions, minimizing trials and errors. With this method, fast and accurate welding simulations can be performed, ultimately leading to improved productivity.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"11 1","pages":"Pages 326-343"},"PeriodicalIF":11.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01DOI: 10.1016/j.joes.2025.10.008
Songmao Zhang , Jinju Liu , Yu Liu , Weiqian Tian , Jingdong Hu , Yuren Wang
Acoustic absorption in underwater coatings decreases with increasing hydrostatic pressure due to pressure-induced morphological changes in embedded air cavities. However, limited experimental characterization and imprecise modeling of cavity deformation under high pressure have hindered both theoretical progress and mechanistic understanding. Here, we use X-ray computed tomography (CT) to measure cavity deformation in situ, establishing a multiscale framework to analyze structural changes over 0–10 MPa. In situ measurements and improved imaging techniques allow accurate tracking of microstructural changes under triaxial stress, revealing patterns of cavity evolution and petal-like deformations caused by edge effects. By combining experiments and simulations, we demonstrate that cavity volume contraction follows a nonlinear power-law dependence on hydrostatic pressure and explain stress-concentration mechanisms at cavity-matrix interfaces. Impedance-tube experiments and numerical modeling show that CT-informed models that account for edge effects outperform simplified models. This work offers technological support and new analytical methods for designing pressure-resistant, low-frequency broadband underwater acoustic coatings.
{"title":"In-situ visualization of hydrostatic-dependent mechanical deformation evolution for underwater acoustic coating using customized X-ray imaging technology","authors":"Songmao Zhang , Jinju Liu , Yu Liu , Weiqian Tian , Jingdong Hu , Yuren Wang","doi":"10.1016/j.joes.2025.10.008","DOIUrl":"10.1016/j.joes.2025.10.008","url":null,"abstract":"<div><div>Acoustic absorption in underwater coatings decreases with increasing hydrostatic pressure due to pressure-induced morphological changes in embedded air cavities. However, limited experimental characterization and imprecise modeling of cavity deformation under high pressure have hindered both theoretical progress and mechanistic understanding. Here, we use X-ray computed tomography (CT) to measure cavity deformation in situ, establishing a multiscale framework to analyze structural changes over 0–10 MPa. In situ measurements and improved imaging techniques allow accurate tracking of microstructural changes under triaxial stress, revealing patterns of cavity evolution and petal-like deformations caused by edge effects. By combining experiments and simulations, we demonstrate that cavity volume contraction follows a nonlinear power-law dependence on hydrostatic pressure and explain stress-concentration mechanisms at cavity-matrix interfaces. Impedance-tube experiments and numerical modeling show that CT-informed models that account for edge effects outperform simplified models. This work offers technological support and new analytical methods for designing pressure-resistant, low-frequency broadband underwater acoustic coatings.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"11 1","pages":"Pages 154-162"},"PeriodicalIF":11.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}