Applied Ocean Research最新文献_第6页

Approximation of sea surface velocity field by fitting surrogate two-dimensional flow to scattered measurements 用散射测量拟合代用二维流来近似海面速度场

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-09-28 DOI: 10.1016/j.apor.2024.104246

In this paper, a rapid approximation method is introduced to estimate the sea surface velocity field based on scattered measurements. The method uses a simplified two-dimensional flow model as a surrogate model, which mimics the real submesoscale flow. The proposed approach treats the interpolation of the flow velocities as an optimization problem, aiming to fit the flow model to the scattered measurements. To ensure consistency between the simulated velocity field and the measured values, the boundary conditions in the numerical simulations are adjusted during the optimization process. Additionally, the relevance of quantity and quality of the scattered measurements is assessed, emphasizing the importance of the measurement locations within the domain as well as explaining how these measurements contribute to the accuracy and reliability of the sea surface velocity field approximation. The proposed methodology has been successfully tested in both synthetic and real-world scenarios, leveraging measurements obtained from Global Positioning System (GPS) drifters and high-frequency (HF) radar systems. The adaptability of this approach for different domains, measurement types and conditions implies that it is suitable for real-world submesoscale scenarios where only an approximation of the sea surface velocity field is sufficient.

本文介绍了一种基于散射测量估算海面速度场的快速近似方法。该方法使用简化的二维流动模型作为代用模型，模拟真实的亚目尺度流动。所提出的方法将流速插值视为一个优化问题，目的是使流速模型与散射测量结果相匹配。为确保模拟速度场与测量值之间的一致性，在优化过程中对数值模拟的边界条件进行了调整。此外，还对散射测量的数量和质量的相关性进行了评估，强调了域内测量位置的重要性，并解释了这些测量如何有助于提高海面速度场近似的准确性和可靠性。利用从全球定位系统（GPS）漂移器和高频（HF）雷达系统获得的测量数据，在合成和实际场景中成功测试了所提出的方法。这种方法对不同领域、测量类型和条件的适应性意味着，它适用于只需近似海面速度场的真实世界次中尺度场景。

{"title":"Approximation of sea surface velocity field by fitting surrogate two-dimensional flow to scattered measurements","authors":"","doi":"10.1016/j.apor.2024.104246","DOIUrl":"10.1016/j.apor.2024.104246","url":null,"abstract":"<div><div>In this paper, a rapid approximation method is introduced to estimate the sea surface velocity field based on scattered measurements. The method uses a simplified two-dimensional flow model as a surrogate model, which mimics the real submesoscale flow. The proposed approach treats the interpolation of the flow velocities as an optimization problem, aiming to fit the flow model to the scattered measurements. To ensure consistency between the simulated velocity field and the measured values, the boundary conditions in the numerical simulations are adjusted during the optimization process. Additionally, the relevance of quantity and quality of the scattered measurements is assessed, emphasizing the importance of the measurement locations within the domain as well as explaining how these measurements contribute to the accuracy and reliability of the sea surface velocity field approximation. The proposed methodology has been successfully tested in both synthetic and real-world scenarios, leveraging measurements obtained from Global Positioning System (GPS) drifters and high-frequency (HF) radar systems. The adaptability of this approach for different domains, measurement types and conditions implies that it is suitable for real-world submesoscale scenarios where only an approximation of the sea surface velocity field is sufficient.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

YOLO-MRS: An efficient deep learning-based maritime object detection method for unmanned surface vehicles YOLO-MRS：基于深度学习的高效无人水面飞行器海洋物体检测方法

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-09-28 DOI: 10.1016/j.apor.2024.104240

Deep learning-based object detection for an unmanned surface vehicle (USV) is an important way of visual perception. However, current methods perform poorly when performing complex maritime object detection tasks. It also lacks available datasets of complex maritime objects for visual perception system of USVs. In order to solve these problems, we propose an improved maritime object detection method, called YOLO-MRS, based on lightweight YOLOv8 model in this paper. Specifically, we introduce a multi-scale cross-axis attention (MCA) mechanism into the backbone network of the model to establish long-distance dependencies between pixels to capture global feature information. In addition, we introduce Simplified Spatial Pyramid Pooling-Fast (SimSPPF) to the backbone to enhance prediction accuracy. Also, considering computational efficiency, we replace the ordinary convolutional layers in the backbone network and neck network with refocused convolutional (RefConv) layers to reduce model parameters. Especially, we construct a maritime object detection dataset, termed MODD-13, which contains over 9000 precisely annotated images. The proposed MODD-13 sufficiently considers the characteristics of object categories (13 types), image diversity, sample independence, and background confusion, and can be used as a benchmark dataset for maritime object detection. The final experimental results show that compared with the representative YOLO series models, YOLO-MRS improves the average mAP50 accuracy by 1.8%–7% and mAP50-95 by 1.1%–11.5%, and effectively balances detection accuracy and computational efficiency, thereby effectively achieving fast and accurate detection of maritime objects.

基于深度学习的无人水面航行器（USV）目标检测是视觉感知的一种重要方式。然而，目前的方法在执行复杂的海上物体检测任务时表现不佳。同时，USV 的视觉感知系统也缺乏可用的复杂海洋物体数据集。为了解决这些问题，我们在本文中提出了一种基于轻量级 YOLOv8 模型的改进型海洋物体检测方法，称为 YOLO-MRS。具体来说，我们在模型的骨干网络中引入了多尺度跨轴关注（MCA）机制，以建立像素间的远距离依赖关系，从而捕捉全局特征信息。此外，我们还在骨干网络中引入了简化空间金字塔池化-快速（SimSPPF）机制，以提高预测精度。同时，考虑到计算效率，我们将骨干网络和颈部网络中的普通卷积层替换为重新聚焦卷积层（RefConv），以减少模型参数。特别是，我们构建了一个包含 9000 多张精确注释图像的海洋物体检测数据集，称为 MODD-13。提出的 MODD-13 充分考虑了物体类别（13 种）、图像多样性、样本独立性和背景混淆等特点，可作为海上物体检测的基准数据集。最终实验结果表明，与具有代表性的 YOLO 系列模型相比，YOLO-MRS 的 mAP50 平均精度提高了 1.8%-7%，mAP50-95 平均精度提高了 1.1%-11.5%，有效平衡了检测精度和计算效率，从而有效实现了对海洋物体的快速准确检测。

{"title":"YOLO-MRS: An efficient deep learning-based maritime object detection method for unmanned surface vehicles","authors":"","doi":"10.1016/j.apor.2024.104240","DOIUrl":"10.1016/j.apor.2024.104240","url":null,"abstract":"<div><div>Deep learning-based object detection for an unmanned surface vehicle (USV) is an important way of visual perception. However, current methods perform poorly when performing complex maritime object detection tasks. It also lacks available datasets of complex maritime objects for visual perception system of USVs. In order to solve these problems, we propose an improved maritime object detection method, called YOLO-MRS, based on lightweight YOLOv8 model in this paper. Specifically, we introduce a multi-scale cross-axis attention (MCA) mechanism into the backbone network of the model to establish long-distance dependencies between pixels to capture global feature information. In addition, we introduce Simplified Spatial Pyramid Pooling-Fast (SimSPPF) to the backbone to enhance prediction accuracy. Also, considering computational efficiency, we replace the ordinary convolutional layers in the backbone network and neck network with refocused convolutional (RefConv) layers to reduce model parameters. Especially, we construct a maritime object detection dataset, termed MODD-13, which contains over 9000 precisely annotated images. The proposed MODD-13 sufficiently considers the characteristics of object categories (13 types), image diversity, sample independence, and background confusion, and can be used as a benchmark dataset for maritime object detection. The final experimental results show that compared with the representative YOLO series models, YOLO-MRS improves the average mAP50 accuracy by 1.8%–7% and mAP50-95 by 1.1%–11.5%, and effectively balances detection accuracy and computational efficiency, thereby effectively achieving fast and accurate detection of maritime objects.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Bayesian modeling and mechanical simulations for fragility curve estimation of the mooring system of marine hydrokinetic devices 贝叶斯建模和机械模拟用于估算海洋水动力装置系泊系统的脆性曲线

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-09-28 DOI: 10.1016/j.apor.2024.104243

This work uses Bayesian modeling and mechanical model simulations through the Ansys-AQWA software to construct fragility curve estimates for marine hydrokinetic devices, more specifically, their mooring system. The fragility curves proposed here associate wind speed levels with the risk of damage to the equipment and could be used to better understand the susceptibility of these devices to damage from hurricanes. Our proposed modeling framework uses acoustic Doppler current profiler measurements from a site located off the North Carolina coast and the RM4 conversion device from the Sandia National Laboratory. By evaluating different scenarios with and without dynamic tension in mooring lines due to changes in current velocities caused by extreme wind speeds, our results indicate that the risks of damage may be significant depending not only on the average current velocity but also on the velocity variation.

这项工作通过 Ansys-AQWA 软件使用贝叶斯建模和机械模型模拟来构建海洋水动力设备的脆性曲线估计值，更具体地说是其系泊系统的脆性曲线估计值。这里提出的脆性曲线将风速水平与设备损坏风险联系起来，可用于更好地了解这些设备易受飓风损坏的程度。我们提出的建模框架使用了来自北卡罗来纳州海岸的声学多普勒海流剖面仪测量数据和桑迪亚国家实验室的 RM4 转换装置。通过评估因极端风速引起的流速变化而导致系泊缆线动态拉伸和不动态拉伸的不同情况，我们的结果表明，损坏风险可能很大，这不仅取决于平均流速，还取决于流速变化。

引用次数: 0

Study on water entry impact characteristics and parameter influence analysis of the vehicle passing through the thin crushed ice zone in a polar environment 极地环境中车辆通过薄碎冰区时的进水冲击特性及参数影响分析研究

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-09-28 DOI: 10.1016/j.apor.2024.104250

The problem of water entry in polar environments holds significant research value for polar resource exploration and military applications. This study uses computational fluid dynamics and the discrete element method (CFD-DEM) to investigate the complex process of a vehicle entering water through a thin crushed ice zone. Experimental data validates the efficiency of the coupling algorithm. The primary focus of this study is to investigate the influence of crushed ice shapes, arrangement patterns, coverage densities, and sizes within thin crushed ice zones on the process of water entry. A comprehensive analysis is carried out to assess how the characteristic parameters of different thin crushed ice zones affect the dynamic behavior of the vehicle during water entry and the movements of the crushed ice. Concurrently, the influence of different velocities of the vehicle on the water entry process through a specific thin crushed ice zone is analyzed. The results show that when the crushed ice is in a regular arrangement, it exhibits a circular immersion phenomenon and a cross-shaped passive movement trend. The arrangement patterns, coverage densities, and sizes of the crushed ice have different effects on the water entry process. Of these factors, the complexity of the influence of crushed ice sizes on the water entry process stands out. Meanwhile, the water entry velocity plays a crucial role in determining the relative significance of the hydrodynamic force and the collision force of crushed ice on the total resistance of the vehicle during water entry. These insights provide valuable guidance for the planning and execution of missions in polar regions.

极地环境中的入水问题对于极地资源勘探和军事应用具有重要的研究价值。本研究利用计算流体动力学和离散元法（CFD-DEM）研究了车辆通过薄碎冰区进入水中的复杂过程。实验数据验证了耦合算法的效率。本研究的主要重点是研究薄碎冰区内碎冰的形状、排列方式、覆盖密度和大小对进水过程的影响。通过综合分析，评估不同薄碎冰区的特征参数如何影响车辆在进水过程中的动态行为以及碎冰的运动。同时，还分析了车辆通过特定薄碎冰区的不同速度对进水过程的影响。结果表明，当碎冰呈规则排列时，它表现出圆形浸入现象和十字形被动运动趋势。碎冰的排列方式、覆盖密度和大小对进水过程有不同的影响。在这些因素中，碎冰大小对进水过程的复杂影响尤为突出。同时，进水速度在决定水动力和碎冰碰撞力对车辆进水过程中总阻力的相对重要性方面起着至关重要的作用。这些见解为极地任务的规划和执行提供了宝贵的指导。

{"title":"Study on water entry impact characteristics and parameter influence analysis of the vehicle passing through the thin crushed ice zone in a polar environment","authors":"","doi":"10.1016/j.apor.2024.104250","DOIUrl":"10.1016/j.apor.2024.104250","url":null,"abstract":"<div><div>The problem of water entry in polar environments holds significant research value for polar resource exploration and military applications. This study uses computational fluid dynamics and the discrete element method (CFD-DEM) to investigate the complex process of a vehicle entering water through a thin crushed ice zone. Experimental data validates the efficiency of the coupling algorithm. The primary focus of this study is to investigate the influence of crushed ice shapes, arrangement patterns, coverage densities, and sizes within thin crushed ice zones on the process of water entry. A comprehensive analysis is carried out to assess how the characteristic parameters of different thin crushed ice zones affect the dynamic behavior of the vehicle during water entry and the movements of the crushed ice. Concurrently, the influence of different velocities of the vehicle on the water entry process through a specific thin crushed ice zone is analyzed. The results show that when the crushed ice is in a regular arrangement, it exhibits a circular immersion phenomenon and a cross-shaped passive movement trend. The arrangement patterns, coverage densities, and sizes of the crushed ice have different effects on the water entry process. Of these factors, the complexity of the influence of crushed ice sizes on the water entry process stands out. Meanwhile, the water entry velocity plays a crucial role in determining the relative significance of the hydrodynamic force and the collision force of crushed ice on the total resistance of the vehicle during water entry. These insights provide valuable guidance for the planning and execution of missions in polar regions.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Landslide mechanisms under rapid sedimentation of marine clay in shelf-slope break 陆架-斜坡断裂处海洋粘土快速沉积作用下的滑坡机制

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-09-27 DOI: 10.1016/j.apor.2024.104242

A numerical method is developed for analyzing the landslide mechanism of layered sediment slopes at the shelf-slope break based on a coupled hydro-mechanical model. The parameters of the numerical model are determined through experimental measurements of seabed sediments. The numerical method is used to simulate the evolution of submarine landslides in the shelf-slope break, and to investigate the variation of excess pore pressure, shear strain and void ratio at the landslide location under rapid sedimentation. It was founded that with the sediment loads, the excess pore pressure in the submarine sediment increases continuously, and the value of maximum excess pore pressure in the critical state reaches 302.4 kPa, creating favorable conditions for submarine landslides. The shear strain at the submarine landslide stratum increases rapidly along the depth to the critical point and then decreases rapidly, and the maximum strain manifests at the potential sliding surface of the submarine slope. The rapid sedimentation significantly increased the excess pore pressure and shear strain of the soil in the landslide area, resulting in submarine landslide. The mechanism presented in this paper is widely applicable and provides a basis for the stability assessment of submarine slopes.

基于水力机械耦合模型，开发了一种数值方法，用于分析陆架-斜坡断裂处层状沉积斜坡的滑坡机理。数值模型的参数是通过对海底沉积物的实验测量确定的。利用数值方法模拟了陆架-斜坡断裂处海底滑坡的演变过程，并研究了在快速沉积作用下滑坡位置的过剩孔隙压力、剪切应变和空隙率的变化。结果表明，随着沉积物荷载的增加，海底沉积物中的过剩孔隙压力不断增大，临界状态下的最大过剩孔隙压力值达到302.4 kPa，为海底滑坡的发生创造了有利条件。海底滑坡地层的剪应变沿深度至临界点迅速增加，然后迅速减小，最大应变表现在海底斜坡的潜在滑动面上。快速的沉积作用大大增加了滑坡区土壤的过剩孔隙压力和剪切应变，导致了海底滑坡的发生。本文提出的机理具有广泛的适用性，为海底斜坡的稳定性评估提供了依据。

{"title":"Landslide mechanisms under rapid sedimentation of marine clay in shelf-slope break","authors":"","doi":"10.1016/j.apor.2024.104242","DOIUrl":"10.1016/j.apor.2024.104242","url":null,"abstract":"<div><div>A numerical method is developed for analyzing the landslide mechanism of layered sediment slopes at the shelf-slope break based on a coupled hydro-mechanical model. The parameters of the numerical model are determined through experimental measurements of seabed sediments. The numerical method is used to simulate the evolution of submarine landslides in the shelf-slope break, and to investigate the variation of excess pore pressure, shear strain and void ratio at the landslide location under rapid sedimentation. It was founded that with the sediment loads, the excess pore pressure in the submarine sediment increases continuously, and the value of maximum excess pore pressure in the critical state reaches 302.4 kPa, creating favorable conditions for submarine landslides. The shear strain at the submarine landslide stratum increases rapidly along the depth to the critical point and then decreases rapidly, and the maximum strain manifests at the potential sliding surface of the submarine slope. The rapid sedimentation significantly increased the excess pore pressure and shear strain of the soil in the landslide area, resulting in submarine landslide. The mechanism presented in this paper is widely applicable and provides a basis for the stability assessment of submarine slopes.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The semi-empirical model for critical bed shear stress in the local scour hole downstream of a submerged structure based on turbulent velocity distribution 基于湍流速度分布的水下结构下游局部冲刷孔临界床面剪应力半经验模型

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-09-27 DOI: 10.1016/j.apor.2024.104238

The investigation of the critical bed shear stress at the bed surface with negative slopes in the scour hole downstream of a submerged structure has primarily relied on experimental methods with limited theoretical exploration. This paper examined the distribution of near-bed flow velocity and turbulence intensity at the equilibrium stage based on physical model experiments of local scour downstream of a submerged weir. Additionally, the current study established equations for calculating the distribution of the near-bed mean flow velocity and relative turbulence intensity at the bed surface of the scour hole with negative slopes. Integrating mechanics, probability theory, and statistics introduced an impact force resulting from water flow on the local bed surface. Furthermore, a semi-empirical model for the dimensionless critical bed shear stress was developed applying this basis. The predicted values of the semi-empirical model were consistent with the measured values. They can be utilized to calculate the critical bed shear stress in the local scour hole downstream of the submerged weirs. The near-bed mean flow velocity and relative turbulence intensity introduced in the equation are key parameters that reflect the microscopic mechanisms on the local bed surface. Utilizing these microscopic parameters also avoids the influence of upstream structural configurations in the scour hole, thus broadening the applicability of the study's findings. This development not only deepens the understanding of velocity distribution patterns on the negative slope of the local scour hole downstream of submerged structures in rivers or the ocean but also offers a theoretical foundation for enhancing the precision of numerical models of local scour and for the application of critical standards of sediment initiation in related studies.

对沉没结构下游冲刷孔负坡床面临界床面剪应力的研究主要依靠实验方法，理论探索有限。本文基于潜流堰下游局部冲刷的物理模型试验，研究了平衡阶段近床流速和湍流强度的分布。此外，本研究还建立了负斜坡冲刷孔床面近床平均流速和相对湍流强度分布的计算公式。综合力学、概率论和统计学，引入了水流对局部床面产生的冲击力。此外，还在此基础上建立了无量纲临界床面剪应力的半经验模型。半经验模型的预测值与测量值一致。这些数值可用于计算潜流堰下游局部冲刷孔的临界床面剪应力。方程中引入的近床平均流速和相对湍流强度是反映局部床面微观机制的关键参数。利用这些微观参数还可以避免冲刷洞上游结构构造的影响，从而扩大研究结果的适用范围。这一进展不仅加深了人们对河流或海洋中沉没结构下游局部冲刷洞负坡上的速度分布模式的理解，而且为提高局部冲刷数值模型的精度以及在相关研究中应用沉积物引发的临界标准提供了理论基础。

{"title":"The semi-empirical model for critical bed shear stress in the local scour hole downstream of a submerged structure based on turbulent velocity distribution","authors":"","doi":"10.1016/j.apor.2024.104238","DOIUrl":"10.1016/j.apor.2024.104238","url":null,"abstract":"<div><div>The investigation of the critical bed shear stress at the bed surface with negative slopes in the scour hole downstream of a submerged structure has primarily relied on experimental methods with limited theoretical exploration. This paper examined the distribution of near-bed flow velocity and turbulence intensity at the equilibrium stage based on physical model experiments of local scour downstream of a submerged weir. Additionally, the current study established equations for calculating the distribution of the near-bed mean flow velocity and relative turbulence intensity at the bed surface of the scour hole with negative slopes. Integrating mechanics, probability theory, and statistics introduced an impact force resulting from water flow on the local bed surface. Furthermore, a semi-empirical model for the dimensionless critical bed shear stress was developed applying this basis. The predicted values of the semi-empirical model were consistent with the measured values. They can be utilized to calculate the critical bed shear stress in the local scour hole downstream of the submerged weirs. The near-bed mean flow velocity and relative turbulence intensity introduced in the equation are key parameters that reflect the microscopic mechanisms on the local bed surface. Utilizing these microscopic parameters also avoids the influence of upstream structural configurations in the scour hole, thus broadening the applicability of the study's findings. This development not only deepens the understanding of velocity distribution patterns on the negative slope of the local scour hole downstream of submerged structures in rivers or the ocean but also offers a theoretical foundation for enhancing the precision of numerical models of local scour and for the application of critical standards of sediment initiation in related studies.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analytical study on lateral buckling of lined pipes under high temperature and high pressure 高温高压下内衬管道横向屈曲的分析研究

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-09-27 DOI: 10.1016/j.apor.2024.104239

The use of lined or clad pipes, which have a highly corrosion-resistant material inner layer, is common in subsea pipelines. Unburied lined pipes may experience lateral buckling under high-temperature and high-pressure conditions. In this study, closed-form analytical solutions for different lateral buckling modes have been developed with the Euler-Bernoulli beam theory. The study also discusses the impact of different buckling modes on the buckled configurations and post-buckling behaviour. In addition, the buckling behaviour of the outer pipe and liner in the post-buckling process is compared. The research indicates that the length of the buckled lined pipe can't be assumed to be a fixed value in lateral buckling analysis. While different types of lateral buckling modes only affect the behaviour of lateral buckled deflection, they have little effect on the axial deformation behaviour of the lined pipe. In the post-buckling process, the axial compressive force in the wall of the liner may be higher than that of the outer pipe when the temperature is sufficiently high.

在海底管道中普遍使用内衬管或包覆管，这种管道的内层具有很强的耐腐蚀性。在高温高压条件下，非埋地内衬管道可能会发生侧向屈曲。在本研究中，利用欧拉-伯努利梁理论开发出了不同侧向屈曲模式的闭式解析解。研究还讨论了不同屈曲模式对屈曲配置和屈曲后行为的影响。此外，还比较了外管和内衬在屈曲后过程中的屈曲行为。研究表明，在横向屈曲分析中，内衬管道的屈曲长度不能假定为固定值。虽然不同类型的侧向屈曲模式只影响侧向屈曲挠度的行为，但对内衬管道的轴向变形行为影响不大。在屈曲后过程中，当温度足够高时，内衬管壁的轴向压缩力可能会高于外层管道的轴向压缩力。

引用次数: 0

Submarine landslide susceptibility assessment integrating frequency ratio with supervised machine learning approach 利用监督机器学习方法综合频率比评估海底滑坡易发性

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-09-26 DOI: 10.1016/j.apor.2024.104237

Marine geological hazard assessment is crucial for the development and utilization of marine resources, among which submarine landslide susceptibility assessment constitutes a key and primary stage. However, current research, especially the application of supervised machine learning in this field remains limited. In this study, nine submarine landslide-related factors in the South-West Iberian margin were gained; including bathymetry, slope, curvature, earthquake magnitude density, distance to fault, distance to volcano, sediment type, pipeline density, and vessel density, and then a submarine landslide inventory was compiled. By combining the frequency ratio with representative supervised machine learning algorithms (logistic regression, random forest, and artificial neural network), the large-scale submarine landslide susceptibility assessment was conducted. The susceptibility result was categorized into five levels utilizing the Jenks breakpoint method, ranging from very low to very high. Meanwhile, all models were evaluated from the perspective of probability characteristics and machine learning. The results showed that the frequency ratio-based supervised machine learning models have more reasonable statistical characteristics and exhibit better accuracy, with the frequency ratio-based artificial neural network model emerging as the most capable of assessing submarine landslide susceptibility in the study area, delivering the most precise results. This study provides a reference for the application of supervised machine learning in submarine landslide susceptibility assessment. The methodology and research findings have the potential to enhance the awareness of submarine landslide risks in this or other regions and facilitate the development of effective risk management strategies.

海洋地质灾害评估对于海洋资源的开发和利用至关重要，其中海底滑坡易发性评估是一个关键的初级阶段。然而，目前的研究，尤其是有监督的机器学习在这一领域的应用仍然有限。在这项研究中，获得了伊比利亚西南边缘地区与海底滑坡相关的九个因素，包括水深、坡度、曲率、震级密度、断层距离、火山距离、沉积物类型、管道密度和船只密度，然后编制了海底滑坡清单。通过将频率比与有代表性的监督机器学习算法（逻辑回归、随机森林和人工神经网络）相结合，进行了大规模的海底滑坡易发性评估。利用詹克斯断点法，将易发性结果划分为从极低到极高的五个等级。同时，从概率特征和机器学习的角度对所有模型进行了评估。结果表明，基于频率比的有监督机器学习模型具有更合理的统计特征，表现出更好的准确性，其中基于频率比的人工神经网络模型最有能力评估研究区域的海底滑坡易损性，提供最精确的结果。这项研究为有监督机器学习在海底滑坡易发性评估中的应用提供了参考。研究方法和研究成果有可能提高该地区或其他地区对海底滑坡风险的认识，促进制定有效的风险管理策略。

{"title":"Submarine landslide susceptibility assessment integrating frequency ratio with supervised machine learning approach","authors":"","doi":"10.1016/j.apor.2024.104237","DOIUrl":"10.1016/j.apor.2024.104237","url":null,"abstract":"<div><div>Marine geological hazard assessment is crucial for the development and utilization of marine resources, among which submarine landslide susceptibility assessment constitutes a key and primary stage. However, current research, especially the application of supervised machine learning in this field remains limited. In this study, nine submarine landslide-related factors in the South-West Iberian margin were gained; including bathymetry, slope, curvature, earthquake magnitude density, distance to fault, distance to volcano, sediment type, pipeline density, and vessel density, and then a submarine landslide inventory was compiled. By combining the frequency ratio with representative supervised machine learning algorithms (logistic regression, random forest, and artificial neural network), the large-scale submarine landslide susceptibility assessment was conducted. The susceptibility result was categorized into five levels utilizing the Jenks breakpoint method, ranging from very low to very high. Meanwhile, all models were evaluated from the perspective of probability characteristics and machine learning. The results showed that the frequency ratio-based supervised machine learning models have more reasonable statistical characteristics and exhibit better accuracy, with the frequency ratio-based artificial neural network model emerging as the most capable of assessing submarine landslide susceptibility in the study area, delivering the most precise results. This study provides a reference for the application of supervised machine learning in submarine landslide susceptibility assessment. The methodology and research findings have the potential to enhance the awareness of submarine landslide risks in this or other regions and facilitate the development of effective risk management strategies.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Real-time assessment of ship collision risk using image processing techniques 利用图像处理技术实时评估船舶碰撞风险

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-09-25 DOI: 10.1016/j.apor.2024.104241

The poor quality or the miss of Automatic Identification System (AIS) data may cause erroneous judgement of the potential navigational risk. Therefore, this study proposes a real-time framework for assessing ship collision risk using onboard video data in order to improve the risk perception ability of navigators. Firstly, the Squeeze-and-Excitation (SE) attention mechanism and the K-means algorithm are simultaneously utilized for the framework to enhance the multi-scale ship detection capability. The Deep-SORT is employed to complete multi-ship feature matching. Secondly, the distances between two ships and their speeds are measured using the pinhole imaging principle based on the ship visual feature extraction results. Moreover, the ship distance-speed correction method is designed to improve the reliability of estimated results. Finally, the effectiveness of the framework is validated using naturalistic driving data from the “He Hua Hai” ship. The results show that the proposed framework could demonstrate an excellent performance in assessing ship collision risk using the onboard video data. The proposed framework could help precisely detect and promptly provide warnings about potential ship collision risks. This could help prevent catastrophic accidents that pose a threat to oceans and coasts, particularly in situations when AIS data proves to be unreliable or ineffective.

自动识别系统（AIS）数据质量差或遗漏可能导致对潜在航行风险的错误判断。因此，本研究提出了一种利用船载视频数据评估船舶碰撞风险的实时框架，以提高导航员的风险感知能力。首先，该框架同时采用了挤压-激发（SE）注意力机制和 K-means 算法，以增强多尺度船舶检测能力。采用 Deep-SORT 算法完成多船特征匹配。其次，根据船舶视觉特征提取结果，利用针孔成像原理测量两船之间的距离和速度。此外，还设计了船距-船速修正方法，以提高估算结果的可靠性。最后，利用 "荷花海 "轮的自然驾驶数据验证了该框架的有效性。结果表明，所提出的框架在利用船载视频数据评估船舶碰撞风险方面表现出色。所提出的框架有助于精确检测潜在的船舶碰撞风险并及时发出警告。这有助于防止对海洋和海岸构成威胁的灾难性事故，尤其是在 AIS 数据证明不可靠或无效的情况下。

{"title":"Real-time assessment of ship collision risk using image processing techniques","authors":"","doi":"10.1016/j.apor.2024.104241","DOIUrl":"10.1016/j.apor.2024.104241","url":null,"abstract":"<div><div>The poor quality or the miss of Automatic Identification System (AIS) data may cause erroneous judgement of the potential navigational risk. Therefore, this study proposes a real-time framework for assessing ship collision risk using onboard video data in order to improve the risk perception ability of navigators. Firstly, the Squeeze-and-Excitation (SE) attention mechanism and the K-means algorithm are simultaneously utilized for the framework to enhance the multi-scale ship detection capability. The Deep-SORT is employed to complete multi-ship feature matching. Secondly, the distances between two ships and their speeds are measured using the pinhole imaging principle based on the ship visual feature extraction results. Moreover, the ship distance-speed correction method is designed to improve the reliability of estimated results. Finally, the effectiveness of the framework is validated using naturalistic driving data from the “He Hua Hai” ship. The results show that the proposed framework could demonstrate an excellent performance in assessing ship collision risk using the onboard video data. The proposed framework could help precisely detect and promptly provide warnings about potential ship collision risks. This could help prevent catastrophic accidents that pose a threat to oceans and coasts, particularly in situations when AIS data proves to be unreliable or ineffective.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Station-keeping strategy in emergency mode for wave gliders considering power shortages 考虑到电力短缺问题的波浪滑翔机应急模式下的定点维持战略

IF 4.3 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2024-09-23 DOI: 10.1016/j.apor.2024.104236

The wave glider (WG) is an autonom surface vehicle (ASV) that is driven only by waves without propellers, and it maintains the power consumption of the control system and various payloads through solar power generation. To cope with the power shortages caused by extreme weather and sudden failures, a station-keeping strategy in emergency mode for WGs is proposed in this paper, so that the WG can remain in the current area with extremely low power consumption. More specifically, according to the power consumption mechanism of the WG, a partition control method is designed to set different operating modes in different areas. Also, an event-triggered (ET) motion control algorithm is proposed to reduce the execution rate of the rudder, which introduces adjustment factors to dynamically adjust the trigger threshold to further cut down rudder steering power consumption. Additionally, an online heading prediction system is developed to predict the submerged glider heading (SGH) of the WG through the float heading (FH) when the rudder management system shuts down. Through simulation and experimental analysis, the strategy in emergency mode can achieve positioning control with extremely low power consumption.

波浪滑翔机（WG）是一种仅靠波浪驱动的自主水面飞行器（ASV），没有螺旋桨，通过太阳能发电维持控制系统和各种有效载荷的功耗。为应对极端天气和突发故障造成的电力短缺，本文提出了一种 WG 应急模式下的驻留策略，使 WG 能以极低的功耗留在当前区域。具体来说，根据 WG 的功耗机制，设计了一种分区控制方法，在不同区域设置不同的运行模式。同时，为了降低方向舵的执行率，提出了一种事件触发（ET）运动控制算法，引入调整因子动态调整触发阈值，进一步降低方向舵转向功耗。此外，还开发了一个在线航向预测系统，当舵管理系统关闭时，通过浮标航向（FH）来预测 WG 的水下滑翔机航向（SGH）。通过仿真和实验分析，应急模式下的策略能够以极低的功耗实现定位控制。

{"title":"Station-keeping strategy in emergency mode for wave gliders considering power shortages","authors":"","doi":"10.1016/j.apor.2024.104236","DOIUrl":"10.1016/j.apor.2024.104236","url":null,"abstract":"<div><div>The wave glider (WG) is an autonom surface vehicle (ASV) that is driven only by waves without propellers, and it maintains the power consumption of the control system and various payloads through solar power generation. To cope with the power shortages caused by extreme weather and sudden failures, a station-keeping strategy in emergency mode for WGs is proposed in this paper, so that the WG can remain in the current area with extremely low power consumption. More specifically, according to the power consumption mechanism of the WG, a partition control method is designed to set different operating modes in different areas. Also, an event-triggered (ET) motion control algorithm is proposed to reduce the execution rate of the rudder, which introduces adjustment factors to dynamically adjust the trigger threshold to further cut down rudder steering power consumption. Additionally, an online heading prediction system is developed to predict the submerged glider heading (SGH) of the WG through the float heading (FH) when the rudder management system shuts down. Through simulation and experimental analysis, the strategy in emergency mode can achieve positioning control with extremely low power consumption.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142310814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0