Journal of Marine Science and Engineering

23 pages, 12263 KiB

Open AccessArticle

Predefined-Time Formation Tracking Control for Underactuated AUVs with Input Saturation and Output Constraints

by Sibo Yao, Yiqi Wang and Zhiguang Feng

J. Mar. Sci. Eng. 2025, 13(9), 1607; https://doi.org/10.3390/jmse13091607 - 22 Aug 2025

In this work, a predefined-time formation output constraint control method is proposed for underactuated AUVs with input saturation. First, a coordinate transformation method is utilized to convert the underactuated AUV system into a fully actuated system form. A universal time-varying asymmetric barrier function [...] Read more.

In this work, a predefined-time formation output constraint control method is proposed for underactuated AUVs with input saturation. First, a coordinate transformation method is utilized to convert the underactuated AUV system into a fully actuated system form. A universal time-varying asymmetric barrier function is constructed to convert the system to an unconstrained form and construct the formation tracking error. Then, a predefined-time formation output constraint control law is designed based on the active disturbance rejection control framework and predefined-time control method, which can achieve the control objective without relying on the precise mathematical model of the system. In addition, to address the input saturation issue, a novel predefined-time auxiliary dynamic system (ADS) is proposed. The proposed method with ADS can ensure that the multi-AUV system with input saturation can complete the formation output constraint tracking control task within a predefined time. Finally, a simulation is designed to verify the effectiveness of the proposed method. Full article

(This article belongs to the Special Issue Design and Application of Underwater Vehicles)

21 pages, 2291 KiB

Open AccessArticle

Class-Incremental Learning-Based Few-Shot Underwater-Acoustic Target Recognition

by Wenbo Wang, Ye Li, Tongsheng Shen and Dexin Zhao

J. Mar. Sci. Eng. 2025, 13(9), 1606; https://doi.org/10.3390/jmse13091606 - 22 Aug 2025

Abstract

This paper proposes an underwater-acoustic class-incremental few-shot learning (UACIL) method for streaming data processing in practical underwater-acoustic target recognition scenarios. The core objective is to expand classification capabilities for new classes while mitigating catastrophic forgetting of existing knowledge. UACIL’s contributions encompass three key [...] Read more.

This paper proposes an underwater-acoustic class-incremental few-shot learning (UACIL) method for streaming data processing in practical underwater-acoustic target recognition scenarios. The core objective is to expand classification capabilities for new classes while mitigating catastrophic forgetting of existing knowledge. UACIL’s contributions encompass three key components: First, to enhance feature discriminability and generalization, an enhanced frequency-domain attention module is introduced to capture both spatial and temporal variation features. Second, it introduces a prototype classification mechanism with two operating modes corresponding to the base-training phase and the incremental training phase. In the base phase, sufficient pre-training is performed on the feature extraction network and the classification heads of inherent categories. In the incremental phase, for streaming data processing, only the classification heads of new categories are expanded and updated, while the parameters of the feature extractor remain stable through prototype classification. Third, a joint optimization strategy using multiple loss functions is designed to refine feature distribution. This method enables rapid deployment without complex cross-domain retraining when handling new data classes, effectively addressing overfitting and catastrophic forgetting in hydroacoustic signal classification. Experimental results with public datasets validate its superior incremental learning performance. The proposed method achieves 92.89% base recognition accuracy and maintains 68.44% overall accuracy after six increments. Compared with baseline methods, it improves base accuracy by 11.14% and reduces the incremental performance-dropping rate by 50.09%. These results demonstrate that UACIL enhances recognition accuracy while alleviating catastrophic forgetting, confirming its feasibility for practical applications. Full article

(This article belongs to the Special Issue Underwater Acoustics: Advances in Modelling, Measurement, and Technological Applications)

37 pages, 1200 KiB

Open AccessArticle

Assessing the Effectiveness of 3D-Printed Ceramic Structures for Coral Restoration: Growth, Survivorship, and Biodiversity Using Visual Surveys and eDNA

by Vriko Yu, Alison D. Corley, Horace Lau, Philip D. Thompson, Zhongyue Wilson Wan, Jane C. Y. Wong, Zoe Kwan Ting Wong, Louise Wai Hung Li, Shelby E. McIlroy and David M. Baker

J. Mar. Sci. Eng. 2025, 13(9), 1605; https://doi.org/10.3390/jmse13091605 - 22 Aug 2025

Abstract

Coral reef degradation has spurred the development of artificial structures to mitigate losses in coral cover. These structures serve as substrates for coral transplantation, with the expectation that growing corals will attract reef-associated taxa—while the substrate’s ability to directly support biodiversity is often [...] Read more.

Coral reef degradation has spurred the development of artificial structures to mitigate losses in coral cover. These structures serve as substrates for coral transplantation, with the expectation that growing corals will attract reef-associated taxa—while the substrate’s ability to directly support biodiversity is often neglected. We evaluated a novel 3D-printed modular tile made of porous terra cotta, designed with complex surface structures to enhance micro- and cryptic biodiversity, through a restoration project in Hong Kong. Over four years, we monitored 378 outplanted coral fragments using diver assessments and photography, while biodiversity changes were assessed through visual surveys and eDNA metabarcoding. Coral survivorship was high, with 88% survival after four years. Visual surveys recorded seven times more fish and almost 60% more invertebrates at the restoration site compared to a nearby unrestored area. eDNA analyses revealed a 23.5% higher eukaryote ASV richness at the restoration site than the unrestored site and 13.3% greater richness relative to a natural reference coral community. This study highlights the tiles’ dual functionality: (1) supporting coral growth and (2) enhancing cryptic biodiversity, an aspect often neglected in traditional reef restoration efforts. Our findings underscore the potential of 3D-printed ceramic structures to improve both coral restoration outcomes and broader reef ecosystem recovery. Full article

(This article belongs to the Section Marine Ecology)

18 pages, 9405 KiB

Open AccessArticle

Design and Optimization of a Connecting Joint for Underwater Autonomous Docking and Separation

by Yan Zhang, Yi Yang, Zhiqiang Hu, Zhichao Wang, Quan Zheng and Chuanzhi Fan

J. Mar. Sci. Eng. 2025, 13(9), 1604; https://doi.org/10.3390/jmse13091604 - 22 Aug 2025

Abstract

In this paper, a connecting joint capable of underwater autonomous docking and separation is proposed, which can be used for a reconfigurable articulated underwater robot (RAU robot). The structural design, optimization, and experimental validation of the connecting joint are presented in detail. First, [...] Read more.

In this paper, a connecting joint capable of underwater autonomous docking and separation is proposed, which can be used for a reconfigurable articulated underwater robot (RAU robot). The structural design, optimization, and experimental validation of the connecting joint are presented in detail. First, the concept of the RAU robot is introduced, along with its different operational modes and the application scenarios. Second, the specific structural design and basic functions of the connecting joint are described. Third, a dynamic model of the docking process between different vehicles is established and simulated by kinematic simulation software. Through discretely sampling the parameter space, the optimal parameter combination is obtained. Finally, a prototype of the connecting joint is fabricated and functional tests are conducted. The impact forces on the docking rods before and after optimization are compared. The results show that the designed connecting joint can fulfill the functional requirements for autonomous docking of the underwater robot, and the maximum impact force is reduced by 27.08% compared to the one before optimization. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

17 pages, 1877 KiB

Open AccessArticle

Obstacle Avoidance Tracking Control of Underactuated Surface Vehicles Based on Improved MPC

by Chunyu Song, Qi Qiao and Jianghua Sui

J. Mar. Sci. Eng. 2025, 13(9), 1603; https://doi.org/10.3390/jmse13091603 - 22 Aug 2025

Abstract

This paper addresses the issue of the poor collision avoidance effect of underactuated surface vehicles (USVs) during local path tracking. A virtual ship group control method is suggested by using Freiner coordinates and a model predictive control (MPC) algorithm. We track the planned [...] Read more.

This paper addresses the issue of the poor collision avoidance effect of underactuated surface vehicles (USVs) during local path tracking. A virtual ship group control method is suggested by using Freiner coordinates and a model predictive control (MPC) algorithm. We track the planned path using the MPC algorithm according to the known vessel state and build a hierarchical weighted cost function to handle the state of the virtual vessel, to ensure that the vessel avoids obstacles while tracking the path. In addition, the control system incorporates an Extended Kalman Filter (EKF) algorithm to minimize the state estimation error by continuously updating the ship state and providing more accurate state estimation for the system in a timely manner. In order to validate the anti-interference and robustness of the control system, the simulation experiment is carried out with the “Yukun” as the research object by adding the interference of wind and wave of level 6. The outcome shows that the algorithm suggested in this paper can accurately perform the trajectory-tracking task and make collision avoidance decisions under six levels of external interference. Compared with the original MPC algorithm, the improved MPC algorithm reduces the maximum rudder angle output value by 58%, the integral absolute error by 46%, and the root mean square error value by 46%. The improved control algorithm reduces the maximum rudder angle output value by 42% and the maximum rudder angle output value by 10%. The control method provides a new technical choice for trajectory tracking and collision avoidance of USVs in complex marine environments, with a reliable theoretical basis and practical application value. Full article

(This article belongs to the Special Issue Control and Optimization of Ship Propulsion System)

► Show Figures

Figure 1

25 pages, 8278 KiB

Open AccessArticle

Calibration and Validation of Slurry Erosion Models for Glass Fibre Composites in Marine Energy Systems

by Payvand Habibi and Saeid Lotfian

J. Mar. Sci. Eng. 2025, 13(9), 1602; https://doi.org/10.3390/jmse13091602 - 22 Aug 2025

Abstract

Erosive wear from suspended sediments significantly threatens the structural integrity and efficiency of composite tidal turbine blades. This study develops a novel framework for predicting erosion in FR4 glass fibre-reinforced polymers (GFRPs)—materials increasingly adopted for marine renewable energy components. While erosion models exist [...] Read more.

Erosive wear from suspended sediments significantly threatens the structural integrity and efficiency of composite tidal turbine blades. This study develops a novel framework for predicting erosion in FR4 glass fibre-reinforced polymers (GFRPs)—materials increasingly adopted for marine renewable energy components. While erosion models exist for metals, their applicability to heterogeneous composites with unique failure mechanisms remains unvalidated. We calibrated the Oka erosion model specifically for FR4 using a complementary experimental–computational approach. High-velocity slurry jet tests (12.5 m/s) were conducted at a 90° impact angle, and erosion was quantified using both gravimetric mass loss and surface profilometry. It revealed a distinctive W-shaped erosion profile with 3–6 mm of peak material removal from the impingement centre. Concurrently, CFD simulations employing Lagrangian particle tracking were used to extract local impact velocities and angles. These datasets were combined in a constrained nonlinear optimisation scheme (SLSQP) to determine material-specific Oka model coefficients. The calibrated coefficients were further validated on an independent 45° impingement case (same particle size and flow conditions), yielding 0.0143 g/h predicted versus 0.0124 g/h measured (15.5% error). This additional case confirms the accuracy and feasibility of the predictive model under input conditions different from those used for calibration. The calibrated model achieved strong agreement with measured erosion rates (R² = 0.844), successfully capturing the progressive matrix fragmentation and fibre debonding, the W-shaped erosion morphology, and highlighting key composite-specific damage mechanisms, such as fibre detachment and matrix fragmentation. By enabling the quantitative prediction of erosion severity and location, the calibrated model supports the optimisation of blade profiles, protective coatings, and maintenance intervals, ultimately contributing to the extended durability and performance of tidal turbine systems. This study presents a procedure and the output of calibration for the Oka erosion model, specifically for a composite material, providing a transferable methodology for erosion prediction in GFRPs subjected to abrasive marine flows. Full article

(This article belongs to the Special Issue Advances in Ships and Marine Structures—Edition II)

► Show Figures

Figure 1

26 pages, 2449 KiB

Open AccessArticle

Site Suitability Assessment and Grid-Forming Battery Energy Storage System Configuration for Hybrid Offshore Wind-Wave Energy Systems

by Yijin Li, Zihao Zhang, Jibo Wang, Zhanqin Wang, Wenhao Xu and Geng Niu

J. Mar. Sci. Eng. 2025, 13(9), 1601; https://doi.org/10.3390/jmse13091601 - 22 Aug 2025

Abstract

Hybrid offshore wind-wave systems play an important role in renewable energy transition. To maximize energy utilization efficiency, a comprehensive assessment to select optimal locations is urgently needed. The hydraulic power characteristics of these systems cause power fluctuations that reduce grid frequency stability. Thus, [...] Read more.

Hybrid offshore wind-wave systems play an important role in renewable energy transition. To maximize energy utilization efficiency, a comprehensive assessment to select optimal locations is urgently needed. The hydraulic power characteristics of these systems cause power fluctuations that reduce grid frequency stability. Thus, a site suitability assessment and a grid-forming battery energy storage system (BESS) configuration method are proposed. Considering energy efficiency, dynamic complementary characteristics, and output stability, a framework integrating three indices of Composite Energy Output Index (CEOI), Time-Shifted Cross-Covariance Index (TS-CCI), and Energy Penetration Balance Index (EPBI) is constructed to assess site suitability. To ensure secure and stable operation of microgrid, the frequency response characteristics of the hybrid system are analyzed, and the corresponding frequency constraint is given. A BESS configuration method considering frequency constraint is developed to minimize life cycle costs and maintain grid stability. Applied to a case study along China’s southeast coast, the assessment method successfully identified the optimal offshore station, confirming its practical applicability. The BESS configuration method is validated on a modified IEEE 30-bus system, with a 6.35% decrease in life cycle cost and complete renewable utilization. This research provides a technical and cost-effective solution for integrating hybrid wind-wave energy into island microgrids. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

13 pages, 2868 KiB

Open AccessArticle

Discovery of Anchimolgus jejuicus n. sp. (Copepoda, Cyclopoida, Anchimolgidae) Associated with the Scleractinian Coral Alveopora japonica Eguchi (Cnidaria) off Jeju Island, Korea: Systematics and Ecological Insights

by Jae-Sang Hong and Il-Hoi Kim

J. Mar. Sci. Eng. 2025, 13(9), 1600; https://doi.org/10.3390/jmse13091600 - 22 Aug 2025

Abstract

A new species of copepod, Anchimolgus jejuicus n. sp., is described based on specimens collected from the external washings of the scleractinian coral Alveopora japonica Eguchi, 1965, off Jeju Island, Korea. The new species closely resembles A. multidentatus Kim, 2003, associated with Alveopora [...] Read more.

A new species of copepod, Anchimolgus jejuicus n. sp., is described based on specimens collected from the external washings of the scleractinian coral Alveopora japonica Eguchi, 1965, off Jeju Island, Korea. The new species closely resembles A. multidentatus Kim, 2003, associated with Alveopora catalai Wells, 1968, from New Caledonia in having similar body lengths and similar shapes of the antennae, mouth organs, and swimming legs. However, the new species can be distinguished from the New Caledonian species by the shorter female caudal ramus, which is 1.70 times longer than wide; by the shorter third endopodal segment of the female antenna, which is 3.35 times longer than wide; by the reduced second spine of the distal lash of the maxilla, which is less than half as long as the first spine; by the relatively shorter inner distal spine of the second endopodal segment of female leg 4, which is 1.56 times longer than the outer spine; by the shorter exopodal segment of female leg 5, which is 3.39 times longer than wide; and by the exopod of male leg 5 armed with one spine and one seta. The present paper reports the northernmost distribution area of the genus Anchimolgus, near the latitude of 33°24′ N off Jeju Island. In addition, the recent rapid increase in populations of the host coral Alveopora japonica around Jeju Island—likely driven by climate change—highlights the significant ecological consequences for both the scleractinian coral and its newly discovered symbiotic copepod. Full article

(This article belongs to the Special Issue Biodiversity and Population Ecology of Marine Invertebrates)

► Show Figures

Figure 1

15 pages, 2690 KiB

Open AccessArticle

Analysis on Inner Flow Field and Hydrodynamic Force on Flexible Mining Pipeline Under Bending States

by Wen-Hua Wang, Lei Wang, Chuang Liu, Li-Jian Wang, Zi-Han Zhao, Lei-Lei Dong, Gang Liu, Ying-Ying Wang, Hai-Bo Sun and Kun Li

J. Mar. Sci. Eng. 2025, 13(8), 1599; https://doi.org/10.3390/jmse13081599 - 21 Aug 2025

Abstract

To investigate the internal flow characteristics of particles during hydraulic lifting in deep-sea mining risers, this study developed a three-dimensional curved riser multiphase flow model based on the Eulerian–Eulerian framework and the RNG k-ε turbulence model. The effects of particle distribution [...] Read more.

To investigate the internal flow characteristics of particles during hydraulic lifting in deep-sea mining risers, this study developed a three-dimensional curved riser multiphase flow model based on the Eulerian–Eulerian framework and the RNG k-ε turbulence model. The effects of particle distribution and pressure loss in the curved section, as well as the influence of curvature radius, were analyzed. Results indicate that particle distributions take concave circular or crescent-shaped patterns, becoming more uniform with larger curvature radii. Pressure on the extrados is consistently greater than on the intrados, with pressure loss increasing in the bend and peaking at the midpoint. A larger curvature radius leads to greater total pressure loss but lower frictional loss. Additionally, the bend experiences a restoring force toward the vertical position, which increases as the curvature radius decreases. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

28 pages, 11764 KiB

Open AccessArticle

Study on Cavitation Flow Structure Evolution in the Hump Region of Water-Jet Pumps Under the Valley Condition

by Yingying Zheng, Yun Long, Min Liu, Hanqiao Han, Kai Wang, Jinqing Zhong and Yun Long

J. Mar. Sci. Eng. 2025, 13(8), 1598; https://doi.org/10.3390/jmse13081598 - 21 Aug 2025

Abstract

During the hydraulic performance experiment, significant vibration and noise were observed in the mixed-flow pump operating in the hump region. Cavitation occurrence in the impeller flow channels was confirmed through the transparent chamber. To analyze cavitation flow structure evolution in the mixed-flow pump, [...] Read more.

During the hydraulic performance experiment, significant vibration and noise were observed in the mixed-flow pump operating in the hump region. Cavitation occurrence in the impeller flow channels was confirmed through the transparent chamber. To analyze cavitation flow structure evolution in the mixed-flow pump, this paper integrates numerical and experimental approaches, capturing cavitation flow structures under the valley condition through high-speed photography technology. During the various stages of cavitation development, the cavitation forms are mostly vortex cavitation, cloud cavitation, and perpendicular vortex cavitation. Impeller rotation induces downstream transport of shedding cloud cavitation shedding structures. Flow blockage occurs when cavitation vortexes obstruct specific passages, accelerating cavitation growth that culminates in head reduction through energy dissipation mechanisms. Vortex evolution analysis revealed enhanced density of small-scale vortex structures with stronger localized core intensity in the impeller and diffuser. Despite larger individual vortex scales, reduced core intensity persists throughout the full flow domain. Concurrently, velocity profile characteristics across flow rates and blade sections (spanwise from tip to root) indicate heightened predisposition to flow separation, recirculation zones, and low-velocity regions during off-design operation. This study provides scientific guidance for enhancing anti-cavitation performance in the hump region. Full article

(This article belongs to the Section Ocean Engineering)

► Show Figures

Figure 1

21 pages, 4204 KiB

Open AccessArticle

Life on Plastics: Deep-Sea Foraminiferal Colonization Patterns and Reproductive Morphology

by Ashley M. Burkett

J. Mar. Sci. Eng. 2025, 13(8), 1597; https://doi.org/10.3390/jmse13081597 - 21 Aug 2025

Abstract

Plastic debris has become a persistent feature of deep-sea ecosystems, yet its role as a habitat for calcifying organisms remains poorly understood. Foraminifera colonization has been observed in significant numbers on plastic surfaces, suggesting that these materials serve as novel and significant deep-sea [...] Read more.

Plastic debris has become a persistent feature of deep-sea ecosystems, yet its role as a habitat for calcifying organisms remains poorly understood. Foraminifera colonization has been observed in significant numbers on plastic surfaces, suggesting that these materials serve as novel and significant deep-sea colonization sites for these abundant calcifying organisms. This study uses deep-sea experimental plastic substrates to examine the colonization and reproductive morphology of the benthic foraminifera Lobatula wuellerstorfi across three locations: Station M (4000 m), Oregon OOI (575 m), and Southern Hydrate Ridge (774 m). A total of 482 individuals were analyzed for morphometric traits, including proloculus diameter, to investigate reproductive morphotypes. The Oregon samples displayed a clear bimodal proloculus size distribution, consistent with alternating reproductive strategies, while Station M populations exhibited a broader, less defined bimodal distribution skewed toward megalospheric forms. A weak but significant increase in proloculus diameter over deployment duration was observed at Station M, suggesting a possible influence of experiment duration and/or substrate maturity and environmental conditions. These findings demonstrate that plastics can serve as persistent colonization sites for deep-sea foraminifera, offering a unique experimental platform to investigate benthic population dynamics, ecological plasticity, and potential geochemical implications, as well as the broader impacts of foraminifera on deep-sea biodiversity and biogeochemical cycling. Full article

(This article belongs to the Special Issue Effects of Ocean Plastic Pollution on Aquatic Life)

► Show Figures

Figure 1

21 pages, 6924 KiB

Open AccessArticle

The Dynamic Response of a Coral Sand Site–Underground Structure System Under Multidimensional Seismic Excitation

by Zixuan Yang, Xiaorui Xie and Wei Ren

J. Mar. Sci. Eng. 2025, 13(8), 1596; https://doi.org/10.3390/jmse13081596 - 21 Aug 2025

Abstract

Seismic response analysis of underground structures at coral sand sites is a critical component in ensuring the structural safety of island reef engineering. Current experimental studies in this field have primarily focused on unidirectional seismic excitation. To investigate the seismic response differences under [...] Read more.

Seismic response analysis of underground structures at coral sand sites is a critical component in ensuring the structural safety of island reef engineering. Current experimental studies in this field have primarily focused on unidirectional seismic excitation. To investigate the seismic response differences under multidirectional seismic loading, this study designed a series of shaking table tests under unidirectional, bidirectional, and triaxial loading schemes. The seismic responses of underground structures and coral sand foundations were compared under different loading conditions, including boundary effects, ground and structural accelerations, Fourier spectra, and structural strains. The results indicate that the soil–structure system exhibits responses in the non-excitation directions during the shaking table tests. Compared to the excitation direction, boundary effects are more pronounced in the non-excitation directions, with vibrations in these directions primarily concentrated in the high-frequency range (16–20 Hz). The ground acceleration amplification factors in the X-, Y-, and Z-directions in different loading directions are 0.9–1.3, 1.4–2, and 3.4–3.7, respectively, showing significant differences. Under triaxial loading, the peak strain in the underground structure is significantly higher than that under unidirectional loading. Full article

(This article belongs to the Topic Coastal Engineering: Past, Present and Future)

► Show Figures

Figure 1

4 pages, 157 KiB

Open AccessEditorial

Wave/Current–Structure–Seabed Interactions Around Offshore Foundations

by Wengang Qi, Shengjie Rui and Zhen Guo

J. Mar. Sci. Eng. 2025, 13(8), 1595; https://doi.org/10.3390/jmse13081595 - 21 Aug 2025

Abstract

The rapid expansion of the offshore energy infrastructure, including wind turbines, subsea pipelines, and marine platforms, has underscored the critical need to overcome the challenges presented by harsh marine environments [...] Full article

(This article belongs to the Special Issue Wave/Current–Structure–Seabed Interactions around Offshore Foundations)

24 pages, 5025 KiB

Open AccessArticle

Upper-Bound Stability Analysis of Cracked Embankment Slopes with Inclined Interlayers Subject to Pore Water Pressure

by Jingwu Zhang, Zehao Yu and Jinxiang Yi

J. Mar. Sci. Eng. 2025, 13(8), 1594; https://doi.org/10.3390/jmse13081594 - 21 Aug 2025

Abstract

This study analyzes the stability of embankment slopes with inclined interlayers and vertical tensile cracks at the crest under saturated conditions. This study first establishes a composite failure mechanism based on a finite element limit analysis; then, it derives an upper-bound solution formula [...] Read more.

This study analyzes the stability of embankment slopes with inclined interlayers and vertical tensile cracks at the crest under saturated conditions. This study first establishes a composite failure mechanism based on a finite element limit analysis; then, it derives an upper-bound solution formula for stability considering pore water pressure; and finally, it verifies the rationality of the method through case comparisons. This study finds that an increase in crack depth (H_c) causes the crack initiation position to approach the crest edge, while increases in the slope angle (β), pore water pressure coefficient (r_u), and interlayer embedment depth (d) lead to the opposite trend. Both the stability number (γH/c₁) and safety factor (F_s) decrease with the increase in the slope angle, pore water pressure coefficient, and crack depth, and they increase with the enhancement of relative soil strength and the increase in interlayer embedment depth. When cracks exist at the crest, the influence of pore water pressure on the sliding surface is diminished, while decreasing the cohesion ratio of interlayer to embankment slope soil (c₂/c₁) expands the range of the critical sliding surface. Full article

(This article belongs to the Section Coastal Engineering)

► Show Figures

Figure 1

35 pages, 3129 KiB

Open AccessArticle

Spatiotemporal Meta-Reinforcement Learning for Multi-USV Adversarial Games Using a Hybrid GAT-Transformer

by Yang Xiong, Shangwen Wang, Hongjun Tian, Guijie Liu, Zihao Shan, Yijie Yin, Jun Tao, Haonan Ye and Ying Tang

J. Mar. Sci. Eng. 2025, 13(8), 1593; https://doi.org/10.3390/jmse13081593 - 20 Aug 2025

Abstract

Coordinating Multi-Unmanned Surface Vehicle (USV) swarms in complex, adversarial maritime environments is a significant challenge, as existing multi-agent reinforcement learning (MARL) methods often fail to capture intricate spatiotemporal dependencies, leading to suboptimal policies. To address this, we propose Adv-TransAC, a novel Spatio-Temporal Meta-Reinforcement [...] Read more.

Coordinating Multi-Unmanned Surface Vehicle (USV) swarms in complex, adversarial maritime environments is a significant challenge, as existing multi-agent reinforcement learning (MARL) methods often fail to capture intricate spatiotemporal dependencies, leading to suboptimal policies. To address this, we propose Adv-TransAC, a novel Spatio-Temporal Meta-Reinforcement Learning framework. Its core innovation is a hybrid GAT-transformer architecture that decouples spatial and temporal reasoning: a Graph Attention Network (GAT) models instantaneous tactical formations, while a transformer analyzes their temporal evolution to infer intent. This is combined with an adversarial meta-learning mechanism to enable rapid adaptation to opponent tactics. In high-fidelity escort and defense simulations, Adv-TransAC significantly outperforms state-of-the-art MARL baselines in task success rate and policy robustness. The learned policies demonstrate the emergence of complex cooperative behaviors, such as intelligent risk-aware coordination and proactive interception maneuvers. The framework’s practicality is further validated by a communication-efficient federated optimization architecture. By effectively modeling spatiotemporal dynamics and enabling rapid adaptation, Adv-TransAC provides a powerful solution that moves beyond reactive decision-making, establishing a strong foundation for next-generation, intelligent maritime platforms. Full article

(This article belongs to the Special Issue Advanced Control Strategies for Autonomous Maritime Systems)

► Show Figures

Figure 1

22 pages, 3781 KiB

Open AccessArticle

Fault-Tolerant Trajectory Tracking Control for a Differential-Driven Unmanned Surface Vehicle with Propeller Faults

by Yuanbo Su, Renhai Yu, Wanyu Tang and Tieshan Li

J. Mar. Sci. Eng. 2025, 13(8), 1592; https://doi.org/10.3390/jmse13081592 - 20 Aug 2025

Abstract

This article investigates the problem of adaptive fault-tolerant trajectory tracking control for a differential-driven unmanned surface vehicle (USV) with propeller faults. A new USV control system considering a propeller servo loop is established, which is composed of kinematics, kinetics including unhealthy surge force [...] Read more.

This article investigates the problem of adaptive fault-tolerant trajectory tracking control for a differential-driven unmanned surface vehicle (USV) with propeller faults. A new USV control system considering a propeller servo loop is established, which is composed of kinematics, kinetics including unhealthy surge force and yaw moment, and propeller motor shaft speed dynamics. Firstly, the control design of the kinematic level derives the virtual surge speed and yaw rate, which can accurately guide the tracking design of the kinetic level. Secondly, by estimating the bound of the unknown propeller fault parameters, the virtual fault-tolerant control laws are constructed in the kinetic level, which can generate the desired motor angular shaft speeds with an active compensation feature. Thirdly, in the control design of the propeller servo loop, the command duty cycles are designed to force the actual motor shaft speeds to track the desired signals produced from the kinetic level. It can be proven that tracking errors are semiglobally ultimately uniformly bounded based on Lyapunov stability theory. Finally, simulations considering single propeller and twin propeller faults prove the validity of the developed method. Full article

(This article belongs to the Special Issue Control and Optimization of Ship Propulsion System)

► Show Figures

Figure 1

5 pages, 163 KiB

Open AccessEditorial

Application of Deep Learning in Underwater Image Processing

by Chia-Hung Yeh, Chua-Chin Wang and Guo-Shiang Lin

J. Mar. Sci. Eng. 2025, 13(8), 1591; https://doi.org/10.3390/jmse13081591 - 20 Aug 2025

Abstract

The ocean covers a significant portion of the Earth’s surface and harbors abundant natural resources, meaning that underwater exploration is of significant importance [...] Full article

(This article belongs to the Special Issue Application of Deep Learning in Underwater Image Processing)

22 pages, 2073 KiB

Open AccessReview

Up-to-Date Scoping Review of Object Detection Methods for Macro Marine Debris

by Zoe Moorton, Kamlesh Mistry, Rebecca Strachan and Shanfeng Hu

J. Mar. Sci. Eng. 2025, 13(8), 1590; https://doi.org/10.3390/jmse13081590 - 20 Aug 2025

Abstract

Being able to accurately identify litter in a marine environment is crucial to cleaning up our seas and oceans. Research into object detection techniques to support this identification has been underway for over two decades. However, there have been substantial advancements in the [...] Read more.

Being able to accurately identify litter in a marine environment is crucial to cleaning up our seas and oceans. Research into object detection techniques to support this identification has been underway for over two decades. However, there have been substantial advancements in the past five years due to the implementation of deep learning techniques. Following the PRISMA-ScR guidelines, we provide an in-depth summary and analysis of recent and significant research contributions to the object detection of macro marine debris. From cross-referencing the results of the literature review, we deduce that there is currently no benchmarked framework for evaluating and comparing computer vision techniques for marine environments. Subsequently, we use the results from our analysis to provide a suggested checklist for future researchers in this field. Furthermore, many of the respected researchers in this field have advocated for a comprehensive database of underwater debris to support research developments in intelligent object detection and identification. Full article

(This article belongs to the Special Issue Underwater Observation Technology in Marine Environment)

► Show Figures

Figure 1

16 pages, 4447 KiB

Open AccessArticle

Evaluation of Free-Surface Exposure Effects on Tidal Turbine Performance Using CFD

by Gyeongseo Min, Wooseok Choi, Haechan Yun, Younguk Do, Kangmin Kim, Weichao Shi, Saishuai Dai, Daejeong Kim and Soonseok Song

J. Mar. Sci. Eng. 2025, 13(8), 1589; https://doi.org/10.3390/jmse13081589 - 19 Aug 2025

Abstract

Tidal turbines represent a promising renewable energy source, generating power from ocean currents. However, due to tidal range variations, they sometimes become partially exposed to the free surface. When this occurs, the turbine experiences reduced power generation and unsteady torque caused by the [...] Read more.

Tidal turbines represent a promising renewable energy source, generating power from ocean currents. However, due to tidal range variations, they sometimes become partially exposed to the free surface. When this occurs, the turbine experiences reduced power generation and unsteady torque caused by the asymmetric flow. Such conditions can lead to long-term degradation of turbine performance and reliability. From this perspective, a key question arises regarding how significantly power generation differs when turbines are exposed to the free surface. This study was conducted with the objective of quantitatively evaluating the differences in power generation and torque acting on the turbine due to free-surface exposure, in order to address this question. Numerical simulations considering free-surface exposure effects were developed to quantitatively assess these phenomena through Computational Fluid Dynamics (CFD). Additionally, this numerical model was validated by comparison against experimental data and verified by convergence tests. The results revealed that the tidal turbine exhibited power generation differences ranging from a maximum of 45% to a minimum of 0.44%, depending on the degree of free-surface exposure. These findings are expected to serve as valuable indicators for power generation when operating tidal turbines. Full article

(This article belongs to the Special Issue Marine CFD: From Resistance Prediction to Environmental Innovation)

► Show Figures

Figure 1

Journal Description

Journal of Marine Science and Engineering

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Further Information

Guidelines

MDPI Initiatives

Follow MDPI