Journal of Marine Science and Engineering

53 pages, 8754 KB

Open AccessReview

Multi-Branch Towed Array System: Systematic Analysis of Modeling Methods, Environmental Responses and Mechanical Properties in Fracture Analysis

by Jin Yan, Kefan Yang, Shengqing Zeng, Keqi Yang, Dapeng Zhang and Keqiang Zhu

J. Mar. Sci. Eng. 2025, 13(9), 1697; https://doi.org/10.3390/jmse13091697 - 2 Sep 2025

Abstract

Multi-branch towed array systems are an important component of subsea information collection, which is increasingly required for subsea pipeline laying and offshore platform construction as ocean energy is exploited. However, the complexity of underwater conditions poses challenges for marine towing systems when collecting [...] Read more.

Multi-branch towed array systems are an important component of subsea information collection, which is increasingly required for subsea pipeline laying and offshore platform construction as ocean energy is exploited. However, the complexity of underwater conditions poses challenges for marine towing systems when collecting information, including the possibility of towing cable collisions with protruding seabed or submerged organisms during towing system travel, or towing cable interactions during torsion. These collisions can affect and interfere with the collection of information by the towing system, and can cause damage to the towing system or even cause the towing cable to break. After the failure and detachment of the outboard guide cable of a multi-branch towing cable array, the formation of the towing system changes, and these changes are complex and related to the prevailing sea state. To study the important condition of the damaged towing system, this paper draws an analogy between the towing system and the trawl net, and speculates the formation change and mechanical response of the multi-branch towed array system after damage by combining the influencing factors of the deployment of the towing system. Full article

(This article belongs to the Special Issue Structural Modelling, Safety Assessment, and Advanced Material Application of Marine Structures)

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20 pages, 5966 KB

Open AccessArticle

Formation Control of Multiple UUVs Based on GRU-KF with Communication Packet Loss

by Juan Li, Rui Luo, Honghan Zhang and Zhenyang Tian

J. Mar. Sci. Eng. 2025, 13(9), 1696; https://doi.org/10.3390/jmse13091696 - 2 Sep 2025

Abstract

In response to the problem of decreased collaborative control performance in underwater unmanned vehicles (UUVs) with communication packet loss, a GRU-KF method for multi-UUV control that integrates a gated recurrent unit (GRU) and a Kalman filter (KF) is proposed. First, a UUV feedback [...] Read more.

In response to the problem of decreased collaborative control performance in underwater unmanned vehicles (UUVs) with communication packet loss, a GRU-KF method for multi-UUV control that integrates a gated recurrent unit (GRU) and a Kalman filter (KF) is proposed. First, a UUV feedback linearization model and a current model are established, and a multi-UUV controller-based leader–follower method is designed, using a neural network-based radial basis function (RBF) to counteract the uncertainty effects in the model. For scenarios involving packet loss in multi-UUV collaborative communication, the GRU network extracts historical temporal features to enhance the system’s adaptability to communication uncertainties, while the KF performs state estimation and error correction. The simulation results show that, compared to compensation by the GRU network, the proposed method significantly reduces the jitter level and convergence time of errors, enabling the formation to exhibit good robustness and accuracy in communication packet loss scenarios. Full article

(This article belongs to the Section Ocean Engineering)

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17 pages, 2740 KB

Open AccessArticle

Empirical Research to Design Rule-Based Strategy Control with Energy Consumption Minimization Strategy of Energy Management Systems in Hybrid Electric Propulsion Systems

by Seongwan Kim and Hyeonmin Jeon

J. Mar. Sci. Eng. 2025, 13(9), 1695; https://doi.org/10.3390/jmse13091695 - 2 Sep 2025

Abstract

Equivalent energy consumption minimization methods of energy management systems have been implemented as a rule-based strategy to enhance electric propulsion system efficiency. This study compares the efficiencies of different systems by applying variable- and constant-speed generators with battery hybrid systems, measuring fuel consumption. [...] Read more.

Equivalent energy consumption minimization methods of energy management systems have been implemented as a rule-based strategy to enhance electric propulsion system efficiency. This study compares the efficiencies of different systems by applying variable- and constant-speed generators with battery hybrid systems, measuring fuel consumption. In the same scenario, the variable-speed operation showed a notable improvement of 10.36% compared to the conventional system. However, in the verification of hybrid system efficiency, onshore charged energy cannot be considered a reduction in fuel consumption. Instead, when converting onshore energy usage into equivalent fuel consumption for comparative analysis, both hybrid constant- and variable-speed operation modes achieved efficiency enhancements ranging from 5.5% to 9.79% compared to the conventional, nonequivalent constant-speed operation mode. Conversely, the nonequivalent variable-speed operation mode demonstrated an efficiency that was 5.41% higher than that of the hybrid constant-speed operation mode. In contrast, the battery-integrated variable-speed operation mode indicated a system efficiency approximately equal to that of the nonequivalent variable-speed operation mode. For vessels with load profiles characterized by prolonged periods of idling or low-load operations, a battery-integrated hybrid system could be a practical solution. This study demonstrates the necessity of analyzing load profiles, even when aiming for the optimal operational set points of the generator engine. Full article

(This article belongs to the Topic Maritime Transportation in the Blue Economy and Green Shipping Technology)

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25 pages, 1623 KB

Open AccessReview

From Form to Function: The Anatomy, Ecology, and Biotechnological Promise of the False-Kelp Saccorhiza polyschides

by Clélia Afonso and Teresa Mouga

J. Mar. Sci. Eng. 2025, 13(9), 1694; https://doi.org/10.3390/jmse13091694 - 2 Sep 2025

Abstract

Saccorhiza polyschides is a fast-growing pioneer and opportunistic canopy-forming false-kelp belonging to the order Phyllariaceae (Ochrophyta, Phaeophyceae). The species plays a pivotal ecological role in temperate marine ecosystems and exhibits promising potential for diverse biotechnological applications. The species, however, is under growing pressure [...] Read more.

Saccorhiza polyschides is a fast-growing pioneer and opportunistic canopy-forming false-kelp belonging to the order Phyllariaceae (Ochrophyta, Phaeophyceae). The species plays a pivotal ecological role in temperate marine ecosystems and exhibits promising potential for diverse biotechnological applications. The species, however, is under growing pressure from anthropogenic disturbance. This review synthesises current knowledge regarding the biology and geographic distribution of the species, with particular emphasis on its distinctive morphology and ultrastructural features. The species’ complex life cycle and marked seasonal productivity are examined concerning environmental variables. Furthermore, we explore the ecological interactions of the species, including its role as a habitat-forming species and its responses to anthropogenic stressors such as climate change and habitat degradation. Special attention is given to the state of knowledge regarding the bioactive compounds and associated bioactivities of S. polyschides. This includes a detailed examination of the species’ phytochemical constituents, extraction and fractionation strategies, as well as in vitro and in vivo bioactivities, and potential biotechnological applications. By integrating findings from recent literature and identifying methodological and knowledge gaps, this paper seeks to provide a comprehensive understanding of S. polyschides as an emergent marine bioresource and to propose directions for future research and sustainable valorisation. Full article

(This article belongs to the Section Marine Biology)

23 pages, 5309 KB

Open AccessReview

Review of Age Estimation Techniques and Growth Models for Shelled Organisms in Marine Animal Forests

by Ömerhan Dürrani, Çağdaş Can Cengiz, Halyna Gabrielczak, Esra Özcan, Madona Varshanidze, Genuario Belmonte and Kadir Seyhan

J. Mar. Sci. Eng. 2025, 13(9), 1693; https://doi.org/10.3390/jmse13091693 - 2 Sep 2025

Abstract

Marine shelled organisms exhibit diverse growth strategies shaped by species-specific traits and environmental conditions that critically influence their ecological roles, particularly within Marine Animal Forests (MAF), which are structurally complex habitats and biodiversity-rich habitats. This review compiles and compares empirical growth data for [...] Read more.

Marine shelled organisms exhibit diverse growth strategies shaped by species-specific traits and environmental conditions that critically influence their ecological roles, particularly within Marine Animal Forests (MAF), which are structurally complex habitats and biodiversity-rich habitats. This review compiles and compares empirical growth data for 16 bivalve and gastropod species across seven families, classified as full MAF contributors (Pinna nobilis, Flexopecten glaber, Pecten maximus, and Placopecten magellanicus), partial MAF contributors (Cerastoderma edule, C. glaucum, Chamelea gallina, Ruditapes philippinarum, Mercenaria mercenaria, Panopea generosa, Anadara kagoshimensis, A. inaequivalvis, and Tegillarca granosa), and ecologically relevant non-MAF species (Buccinum undatum, Hexaplex trunculus, and Rapana venosa). Age estimation methods included direct techniques, such as shell growth ring and opercular annulus analysis, alongside indirect approaches, such as length-frequency analysis, stable isotope profiling, and mark–recapture studies. Growth trajectories were modelled using von Bertalanffy growth function (VBGF) parameters to estimate the shell size from ages 1 to 4. Based on these estimates, species were categorised into slow, moderate, fast, and exceptional growth groups. These classifications were further explored through hierarchical clustering that grouped species according to their VBGF-derived growth values, revealing consistent and contrasting life history strategies. This comparative analysis should enhance the understanding of molluscan growth dynamics and support the conservation and management of MAF-associated ecosystems by informing restoration planning, guiding species selection, and contributing to evidence-based policy development. Full article

(This article belongs to the Section Marine Biology)

15 pages, 2854 KB

Open AccessArticle

The Physical Significance and Applications of F_TIDE in Nonstationary Tidal Analysis

by Shengyi Jiao, Yunfei Zhang, Xuefeng Cao, Wei Zhou and Xianqing Lv

J. Mar. Sci. Eng. 2025, 13(9), 1692; https://doi.org/10.3390/jmse13091692 - 2 Sep 2025

Abstract

F_TIDE has been proven to be effective in obtaining the time-varying harmonic parameters of nonstationary tidal signals, and the results near the two endpoints of the analyzed time series are more accurate than those obtained by S_TIDE, which provides good conditions for the [...] Read more.

F_TIDE has been proven to be effective in obtaining the time-varying harmonic parameters of nonstationary tidal signals, and the results near the two endpoints of the analyzed time series are more accurate than those obtained by S_TIDE, which provides good conditions for the prediction of future sea levels. In this paper, F_TIDE is used for the short-term prediction of nonstationary tides in Nome (Alaska) and South Beach (Oregon). The significance of each standard parameter of F_TIDE is quantified by calculating its signal-to-noise ratio to determine the appropriate parameters that can be used for prediction. F_TIDE performs well in forecasting the sea level for three weeks at the Nome gauge and one week at the South Beach gauge. F_TIDE causes 30.1% and 42.0% decreases in the mean absolute errors between the forecasts and the observations compared to T_TIDE. F_TIDE is applied to the original signal at the Nome gauge, and the results show a strong correlation between the variation in M₂ amplitude and the variation in the mean sea level. A potential mechanism is speculated in that changes in tides are affected by the changes in water depth on different time scales, which the sea level pressure, wind, sea ice, and other marine motions may contribute to. Full article

(This article belongs to the Section Physical Oceanography)

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22 pages, 10287 KB

Open AccessArticle

Spatial and Seasonal Characteristics of the Submesoscale Energetics in the Northwest Pacific Subtropical Ocean

by Yunlong Fei, Shaoqing Zhang, Kaidi Wang, Yangyang Yu, Yang Gao and Tong Cui

J. Mar. Sci. Eng. 2025, 13(9), 1691; https://doi.org/10.3390/jmse13091691 - 2 Sep 2025

Abstract

The spatial and seasonal characteristics of submesoscales in the Northwest Pacific Subtropical Ocean are thoroughly investigated here using a submesoscale-permitting model within a localized multiscale energetics framework, in which three scale windows termed background, mesoscale, and submesoscale are decomposed. It is found that [...] Read more.

The spatial and seasonal characteristics of submesoscales in the Northwest Pacific Subtropical Ocean are thoroughly investigated here using a submesoscale-permitting model within a localized multiscale energetics framework, in which three scale windows termed background, mesoscale, and submesoscale are decomposed. It is found that submesoscale energetics are highly geographically inhomogeneous. In the Luzon Strait, baroclinic and barotropic instabilities are the primary mechanisms for generating submesoscale available potential energy (APE) and kinetic energy (KE), and they exhibit no significant seasonal variations. Although buoyancy conversion experiences pronounced seasonal cycles and serves as the main sink of submesoscale APE in winter and spring, its contribution to submesoscale KE is negligible. The major sinks of submesoscale KE are advection, horizontal pressure work, and dissipation. In the Western Boundary Current transition and Subtropical Countercurrent (STCC) interior open ocean zone, submesoscales undergo significant seasonality, with large magnitudes in winter and spring. In spring and winter, baroclinic instability dominates the generation of submesoscale APE via forward cascades, while KE is mainly energized by buoyancy conversion and dissipated by the residual term. Meanwhile, in summer and autumn, submesoscales are considerably weak. Additionally, submesoscale energetics in the Western Boundary Current transition zone are slightly greater than those in the STCC interior open ocean zone, which is attributed to the strengthened straining of the Western Boundary Current and mesoscale eddies. Full article

(This article belongs to the Section Physical Oceanography)

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4 pages, 156 KB

Open AccessEditorial

Sustainable Maritime Transportation in Fluctuating Market: Technologies, Innovations, and Challenges

by Guangnian Xiao and Lang Xu

J. Mar. Sci. Eng. 2025, 13(9), 1690; https://doi.org/10.3390/jmse13091690 - 2 Sep 2025

Abstract

Maritime transport, carrying over 80% of global trade volume, remains the most energy-efficient mode for long-distance cargo transportation [...] Full article

(This article belongs to the Special Issue Sustainable Maritime Transportation in Fluctuating Market: Technologies, Innovations, and Challenges)

5 pages, 168 KB

Open AccessEditorial

Advances in Marine Gas Hydrate Exploration and Discovery

by Wei Zhang, Pibo Su, Jiliang Wang and Qianyong Liang

J. Mar. Sci. Eng. 2025, 13(9), 1689; https://doi.org/10.3390/jmse13091689 - 2 Sep 2025

Abstract

Natural gas hydrates are extensively distributed across terrestrial permafrost zones and continental margins worldwide [...] Full article

(This article belongs to the Special Issue Advances in Marine Gas Hydrate Exploration and Discovery)

24 pages, 325 KB

Open AccessReview

Review of Ship Risk Analyses Through Deficiencies Found in Port State Inspections

by Jose Manuel Prieto, David Almorza, Victor Amor-Esteban and Nieves Endrina

J. Mar. Sci. Eng. 2025, 13(9), 1688; https://doi.org/10.3390/jmse13091688 - 1 Sep 2025

Abstract

This literature review examines the relationship between the number and type of deficiencies identified during Port State Control (PSC) inspections and a ship’s overall risk. The main objective is to synthesise the current academic evidence, detailing the analytical methodologies employed and highlighting key [...] Read more.

This literature review examines the relationship between the number and type of deficiencies identified during Port State Control (PSC) inspections and a ship’s overall risk. The main objective is to synthesise the current academic evidence, detailing the analytical methodologies employed and highlighting key research contributions. The selection of literature has focused on peer-reviewed articles and relevant doctoral theses addressing detention risk prediction, accident risk and ship risk profiling. The findings indicate a consistent correlation between PSC deficiencies and ship risk, although the nature and strength of this correlation may vary depending on the type of risk considered and the specific deficiencies. A methodological evolution is observed in the field, from descriptive statistical analyses and regressions towards more complex predictive models, such as Machine Learning (ML) and Bayesian Networks (BNs). This transition reflects a search for greater accuracy in risk assessment, going beyond simple numerical correlation to improve the selection of ships for inspection. Multivariate statistical techniques, on the other hand, focus on the identification of risk patterns and the evaluation of the PSC system. The conclusions underline the importance of deficiencies as indicators of risk, the need for differentiated inspection approaches and the persistent challenges related to data quality and model interpretability. Full article

(This article belongs to the Section Ocean Engineering)

25 pages, 16356 KB

Open AccessArticle

Synchronization Control for AUVs via Optimal-Sliding-Mode Adaptive Dynamic Programming with Actuator Saturation and Performance Constraints in Dynamic Recovery

by Puxin Chai, Zhenyu Xiong, Wenhua Wu, Yushan Sun and Fukui Gao

J. Mar. Sci. Eng. 2025, 13(9), 1687; https://doi.org/10.3390/jmse13091687 - 1 Sep 2025

Abstract

This paper proposes an optimal-sliding-mode-based adaptive dynamic programming (ADP) master–slave synchronous control strategy for the actuator saturation and performance constraints that AUVs face in dynamic recovery. First, by introducing the sliding-mode function into the value function to optimize the state error and its [...] Read more.

This paper proposes an optimal-sliding-mode-based adaptive dynamic programming (ADP) master–slave synchronous control strategy for the actuator saturation and performance constraints that AUVs face in dynamic recovery. First, by introducing the sliding-mode function into the value function to optimize the state error and its derivative simultaneously, the convergence speed is significantly improved. Second, by designing the performance constraint function to directly map the sliding-mode function, the evolution trajectory of the sliding-mode function is constrained, ensuring the steady-state and transient characteristics. In addition, the hyperbolic tangent function (tanh) is introduced into the value function to project the control inputs into an unconstrained policy domain, thereby eliminating the phase lag inherent in conventional saturation compensation schemes. Finally, the requirement for initial stability is relaxed by constructing a single-critic network to approximate the optimal control policy. The simulation results show that the proposed method has significant advantages in terms of the position and attitude synchronization error convergence rate, steady-state accuracy, and control signal continuity compared with the conventional ADP method. Full article

(This article belongs to the Section Ocean Engineering)

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24 pages, 4874 KB

Open AccessArticle

Impact of Non-Gaussian Winds on Blade Loading and Fatigue of Floating Offshore Wind Turbines

by Shu Dai, Bert Sweetman and Shanran Tang

J. Mar. Sci. Eng. 2025, 13(9), 1686; https://doi.org/10.3390/jmse13091686 - 1 Sep 2025

Abstract

This study introduces a novel methodology for estimating loading and fatigue damage in the blades of wind turbines, emphasizing non-Gaussian wind conditions’ impact. By calculating blade loading and fatigue using higher statistical moments of the irregular winds, the study demonstrates the significance of [...] Read more.

This study introduces a novel methodology for estimating loading and fatigue damage in the blades of wind turbines, emphasizing non-Gaussian wind conditions’ impact. By calculating blade loading and fatigue using higher statistical moments of the irregular winds, the study demonstrates the significance of non-Gaussian effects on loading and fatigue predictions. A two-step methodology is developed to synthesize non-Gaussian wind processes, integrating the TurbSim (version 1.5) and Hermite moment model transformation methods. These wind time histories are then utilized in a fully coupled simulation of a floating wind turbine, integrating with a blade beam model. Preliminary analysis of wind thrust and the blade root bending moment indicates non-Gaussian effects on aerodynamic loading. Further analysis of fatigue reveals that fatigue hot spots vary along the blade surface, depending on short-term wind conditions and long-term wind distribution, with total fatigue life estimated by summing the fatigue damage at each potential hot spot. The probability density function of long-term wind process is estimated by fitting the Weibull distribution to measured buoy data. The results show that variations in long-term wind speed distributions lead to an average fatigue life difference of about 1.3 years (16%). The Gaussian wind model overestimates fatigue life by roughly 1.5 years (18%) compared to the non-Gaussian model. This highlights the importance of considering both long-term wind distributions and short-term wind characteristics for accurate fatigue assessment. The findings provide valuable insights for the design and operation of floating offshore wind turbines. Full article

(This article belongs to the Section Ocean Engineering)

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24 pages, 5512 KB

Open AccessArticle

Stability Evaluation of a Damaged Ship with Ice Accumulation in Arctic Regions

by Jiabin Tao, Wei Chai, Xiaonan Yang, Wenzhe Zhang, Chong Wang and Jianzhang Qi

J. Mar. Sci. Eng. 2025, 13(9), 1685; https://doi.org/10.3390/jmse13091685 - 1 Sep 2025

Abstract

The harsh environment in Arctic regions presents significant challenges to ship stability, particularly when ice accumulation and hull damage occur simultaneously, potentially increasing the risk of instability. This study addresses this critical issue by proposing a comprehensive stability assessment framework for ships operating [...] Read more.

The harsh environment in Arctic regions presents significant challenges to ship stability, particularly when ice accumulation and hull damage occur simultaneously, potentially increasing the risk of instability. This study addresses this critical issue by proposing a comprehensive stability assessment framework for ships operating in Arctic regions. Utilizing the DTMB-5415 ship model, the evaluation integrates both static and dynamic stability under combined ice accumulation and damage conditions. Firstly, an ice accumulation prediction model was developed to estimate ice accumulation over various durations. Subsequently, the static stability of damaged ships with ice accumulation was evaluated. Computational Fluid Dynamics (CFD) simulations were then conducted to calculate roll damping coefficients and analyze the effects of damage location and ice accumulation on free roll decay behavior. A single-degree-of-freedom (SDOF) roll motion model was constructed, incorporating roll damping coefficients and wave excitation moments to simulate roll responses in random wave environments. Extreme value prediction was employed to estimate the short-term extreme response distribution of roll motions. The results indicate that ship stability decreases significantly when ice accumulation and hull damage occur simultaneously. This integrated framework provides a systematic foundation for evaluating ship stability in the Arctic environment, specifically accounting for the combined effects of ice accretion and hull damage. Full article

(This article belongs to the Special Issue Numerical Simulation of Fluid-Structure Interactions by CFD (2nd Edition))

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5 pages, 160 KB

Open AccessEditorial

Advances in Marine Geological and Geotechnical Hazards

by Lele Liu, Qingbing Liu and Dengfeng Fu

J. Mar. Sci. Eng. 2025, 13(9), 1684; https://doi.org/10.3390/jmse13091684 - 1 Sep 2025

Abstract

Since the first hearth was kindled, energy has steered human destiny, and today the ocean offers its own vast portfolio [...] Full article

(This article belongs to the Special Issue Advances in Marine Geological and Geotechnical Hazards)

36 pages, 40569 KB

Open AccessArticle

Deep Learning Approaches for Fault Detection in Subsea Oil and Gas Pipelines: A Focus on Leak Detection Using Visual Data

by Viviane F. da Silva, Theodoro A. Netto and Bessie A. Ribeiro

J. Mar. Sci. Eng. 2025, 13(9), 1683; https://doi.org/10.3390/jmse13091683 - 1 Sep 2025

Abstract

The integrity of subsea oil and gas pipelines is essential for offshore safety and environmental protection. Conventional leak detection approaches, such as manual inspection and indirect sensing, are often costly, time-consuming, and prone to subjectivity, motivating the development of automated methods. In this [...] Read more.

The integrity of subsea oil and gas pipelines is essential for offshore safety and environmental protection. Conventional leak detection approaches, such as manual inspection and indirect sensing, are often costly, time-consuming, and prone to subjectivity, motivating the development of automated methods. In this study, we present a deep learning-based framework for detecting underwater leaks using images acquired in controlled experiments designed to reproduce representative conditions of subsea monitoring. The dataset was generated by simulating both gas and liquid leaks in a water tank environment, under scenarios that mimic challenges observed during Remotely Operated Vehicle (ROV) inspections along the Brazilian coast. It was further complemented with artificially generated synthetic images (Stable Diffusion) and publicly available subsea imagery. Multiple Convolutional Neural Network (CNN) architectures, including VGG16, ResNet50, InceptionV3, DenseNet121, InceptionResNetV2, EfficientNetB0, and a lightweight custom CNN, were trained with transfer learning and evaluated on validation and blind test sets. The best-performing models achieved stable performance during training and validation, with macro F1-scores above 0.80, and demonstrated improved generalization compared to traditional baselines such as VGG16. In blind testing, InceptionV3 achieved the most balanced performance across the three classes when trained with synthetic data and augmentation. The study demonstrates the feasibility of applying CNNs for vision-based leak detection in complex underwater environments. A key contribution is the release of a novel experimentally generated dataset, which supports reproducibility and establishes a benchmark for advancing automated subsea inspection methods. Full article

(This article belongs to the Section Ocean Engineering)

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27 pages, 5198 KB

Open AccessArticle

A Nonlinear Filter Based on Fast Unscented Transformation with Lie Group State Representation for SINS/DVL Integration

by Pinglan Li, Fang He and Lubin Chang

J. Mar. Sci. Eng. 2025, 13(9), 1682; https://doi.org/10.3390/jmse13091682 - 1 Sep 2025

Abstract

This study addresses the nonlinear estimation problem in the strapdown inertial navigation system (SINS) and Doppler velocity log (DVL) integrated navigation by proposing an improved filtering algorithm based on

S E_{2} (3)

Lie group state representation. A dynamic model satisfying [...] Read more.

This study addresses the nonlinear estimation problem in the strapdown inertial navigation system (SINS) and Doppler velocity log (DVL) integrated navigation by proposing an improved filtering algorithm based on

S E_{2} (3)

Lie group state representation. A dynamic model satisfying the group affine condition is established to systematically construct both left-invariant and right-invariant error state spaces, upon which two nonlinear filtering approaches are developed. Although the fast unscented transformation method is not novel by itself, its first integration with the

S E_{2} (3)

Lie group model for SINS/DVL integrated navigation represents a significant advancement. Experimental results demonstrate that under large misalignment angles, the proposed method achieves slightly lower attitude errors compared to linear approaches, while also reducing position estimation errors during dynamic maneuvers. The 12,000 s endurance test confirms the algorithm’s stable long-term performance. Compared with conventional unscented Kalman filter methods, the proposed approach not only reduces computation time by 90% but also achieves real-time processing capability on embedded platforms through optimized sampling strategies and hierarchical state propagation mechanisms. These innovations provide an underwater navigation solution that combines theoretical rigor with engineering practicality, effectively overcoming the computational efficiency and dynamic adaptability limitations of traditional nonlinear filtering methods. Full article

(This article belongs to the Section Ocean Engineering)

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14 pages, 13739 KB

Open AccessArticle

Reconstruction of the Cretaceous Palaeogeographic Position of Hainan Island and Its Tectonic Significance

by Mingming Wang, Yang Zhou, Yongjian Yao, Weijie Zhang, Huaiyang Zhou and Qingsong Liu

J. Mar. Sci. Eng. 2025, 13(9), 1681; https://doi.org/10.3390/jmse13091681 - 1 Sep 2025

Abstract

Reconstruction of the palaeogeographical location of Hainan Island is important for understanding the interaction between Indochina and South China. In this study, we integrate topographic relief, gravity anomalies, and magnetic anomalies, along with geological constraints, to determine the Cretaceous location of Hainan Island. [...] Read more.

Reconstruction of the palaeogeographical location of Hainan Island is important for understanding the interaction between Indochina and South China. In this study, we integrate topographic relief, gravity anomalies, and magnetic anomalies, along with geological constraints, to determine the Cretaceous location of Hainan Island. The results show that Hainan Island was connected with South China in the Cretaceous and located in the Beibu Gulf Basin, and then rifted from South China with about 230 km displacement along the southeast direction during the Cenozoic. Further geological evidence suggests that Hainan Island and South China have co-evolved since at least the Permian. Hainan Island was rifted from South China from the Palaeocene to the Oligocene due to escape tectonics caused by the India–Asia collision. These new findings provide important clues for investigating the impact of the India–Asia collision and the continental margin evolution of South China. Full article

(This article belongs to the Section Geological Oceanography)

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21 pages, 1863 KB

Open AccessArticle

Enhancing Phytoplankton Recognition Through a Hybrid Dataset and Morphological Description-Driven Prompt Learning

by Yubo Huo, Qingxuan Lv and Junyu Dong

J. Mar. Sci. Eng. 2025, 13(9), 1680; https://doi.org/10.3390/jmse13091680 - 1 Sep 2025

Abstract

Phytoplankton plays a pivotal role in marine ecosystems and global biogeochemical cycles. Accurate identification and monitoring of phytoplankton are essential for understanding environmental dynamics and climate variations. Despite the significant progress made in automatic phytoplankton identification, current datasets predominantly consist of idealized laboratory [...] Read more.

Phytoplankton plays a pivotal role in marine ecosystems and global biogeochemical cycles. Accurate identification and monitoring of phytoplankton are essential for understanding environmental dynamics and climate variations. Despite the significant progress made in automatic phytoplankton identification, current datasets predominantly consist of idealized laboratory images, leading to models that demonstrate persistent limitations in the fine-grained differentiation of phytoplankton species. To achieve high accuracy and transferability for morphologically similar species and diverse ecosystems, we introduce a hybrid dataset by integrating laboratory-based observations with in situ marine environmental data. We evaluate the performance of our dataset on contemporary deep learning models, revealing that CNN-based architectures offer superior stability (85.27% mAcc., 93.76% oAcc.). Multimodal learning facilitates refined phytoplankton recognition through the integration of visual and textual representations, thereby enhancing the model’s semantic comprehension capabilities. We present a fine-tuned visual language model leveraging enhanced textual prompts augmented with expert-annotated morphological descriptions, significantly enhancing visual-semantic alignment and allowing for more accurate and interpretable recognition of closely related species (84.11% mAcc., 94.48% oAcc.). Our research establishes a benchmark dataset that facilitates real-time ecological monitoring and aquatic biodiversity research. Furthermore, it also contributes to the field by enhancing model robustness and transferability to diverse environmental contexts and taxonomically similar species. Full article

(This article belongs to the Section Marine Biology)

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23 pages, 3138 KB

Open AccessArticle

Design of Organic Rankine Cycle Recovering Multi-Grade Waste Heat from a Two-Stroke Marine Engine

by Jinfeng Feng, Yuncheng Gu, Shengjun Han, Xunhu Zhao, Yujun Tang, Sipeng Zhu, Hao Yuan and Guihua Wang

J. Mar. Sci. Eng. 2025, 13(9), 1679; https://doi.org/10.3390/jmse13091679 - 1 Sep 2025

Abstract

Waste heat recovery using Organic Rankine Cycle (ORC) systems shows significant potential for reducing CO₂ emissions from ships. This study designs and analyzes ORC systems for recovering multi-grade waste heat from the exhaust gas, jacket water, and scavenging air of a marine [...] Read more.

Waste heat recovery using Organic Rankine Cycle (ORC) systems shows significant potential for reducing CO₂ emissions from ships. This study designs and analyzes ORC systems for recovering multi-grade waste heat from the exhaust gas, jacket water, and scavenging air of a marine two-stroke diesel engine. A thermodynamic model is developed to investigate the effects of working fluid preheating temperature, evaporation pressure, and heat source conditions on system performance. Results show that appropriately increasing the preheating temperature of the working fluid can enhance power output. For hydrocarbons with higher critical temperatures, power output exhibits an extremum as preheating temperature increases, while for fluids with lower critical temperatures, power output increases continuously until the evaporation pressure limit is reached. Increasing evaporation pressure decreases power output but improves thermal efficiency, with a corresponding increase in heat transfer and exergy loss rates in the exhaust gas preheater. Additionally, the temperature of the heat source has an important effect on the energy and exergy balance distribution and power output of the ORC. For every 10 K rise in exhaust temperature, the bottoming cycle power output of cyclohexane increases by approximately 12.3%. This study provides theoretical support for efficient marine waste heat recovery and working fluid selection. Full article

(This article belongs to the Section Ocean Engineering)

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