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Search Results (2,289)

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18 pages, 605 KiB  
Article
Enhancing the Regulatory Framework for Incineration at Sea in Peru: Implementing the 1996 London Protocol for Effective Maritime Environmental Governance
by Carlos Gonzalo Carranza Rodriguez, Yeon S. Chang and Hyewon Jang
Sustainability 2025, 17(15), 7060; https://doi.org/10.3390/su17157060 - 4 Aug 2025
Abstract
Incineration at sea is a significant source of marine pollution, threatening biodiversity and public health. Although Peru ratified the 1996 London Protocol in 2018, key deficiencies persist in its domestic legal framework, particularly the absence of clear and internationally aligned definitions for “incineration” [...] Read more.
Incineration at sea is a significant source of marine pollution, threatening biodiversity and public health. Although Peru ratified the 1996 London Protocol in 2018, key deficiencies persist in its domestic legal framework, particularly the absence of clear and internationally aligned definitions for “incineration” and “incinerator.” These gaps hinder effective enforcement by the National Maritime Authority (NMA-DICAPI) and limit regulatory compliance with international obligations. This study analyzes Peru’s current legislation in light of the London Protocol and includes a comparative overview of regional regulatory approaches in Latin America. Based on this analysis, the study identifies regulatory inconsistencies that compromise environmental protection and proposes three key legal reforms: (1) refining the definition of “incineration” to reflect international standards; (2) formally incorporating a definition for “incinerator”; and (3) establishing specific administrative and economic sanctions for related infractions. Through comparative analysis with Mexico and Colombia’s approaches, we propose targeted amendments including refined definitions aligned with IMO standards and explicit administrative/economic sanctions. Implementing these recommendations would enhance Peru’s legal clarity, enforcement capacity, and compliance with international maritime law, reinforcing its role as a responsible actor in marine environmental governance. Full article
23 pages, 1302 KiB  
Article
Deep Learning-Enhanced Ocean Acoustic Tomography: A Latent Feature Fusion Framework for Hydrographic Inversion with Source Characteristic Embedding
by Jiawen Zhou, Zikang Chen, Yongxin Zhu and Xiaoying Zheng
Information 2025, 16(8), 665; https://doi.org/10.3390/info16080665 - 4 Aug 2025
Abstract
Ocean Acoustic Tomography (OAT) is an important marine remote sensing technique used for inverting large-scale ocean environmental parameters, but traditional methods face challenges in computational complexity and environmental interference. This paper proposes a causal analysis-driven AI FOR SCIENCE method for high-precision and rapid [...] Read more.
Ocean Acoustic Tomography (OAT) is an important marine remote sensing technique used for inverting large-scale ocean environmental parameters, but traditional methods face challenges in computational complexity and environmental interference. This paper proposes a causal analysis-driven AI FOR SCIENCE method for high-precision and rapid inversion of oceanic hydrological parameters in complex underwater environments. Based on the open-source VTUAD (Vessel Type Underwater Acoustic Data) dataset, the method first utilizes a fine-tuned Paraformer (a fast and accurate parallel transformer) model for precise classification of sound source targets. Then, using structural causal models (SCM) and potential outcome frameworks, causal embedding vectors with physical significance are constructed. Finally, a cross-modal Transformer network is employed to fuse acoustic features, sound source priors, and environmental variables, enabling inversion of temperature and salinity in the Georgia Strait of Canada. Experimental results show that the method achieves accuracies of 97.77% and 95.52% for temperature and salinity inversion tasks, respectively, significantly outperforming traditional methods. Additionally, with GPU acceleration, the inference speed is improved by over sixfold, aimed at enabling real-time Ocean Acoustic Tomography (OAT) on edge computing platforms as smart hardware, thereby validating the method’s practicality. By incorporating causal inference and cross-modal data fusion, this study not only enhances inversion accuracy and model interpretability but also provides new insights for real-time applications of OAT. Full article
(This article belongs to the Special Issue Advances in Intelligent Hardware, Systems and Applications)
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22 pages, 3275 KiB  
Article
Research on Q-Learning-Based Cooperative Optimization Methodology for Dynamic Task Scheduling and Energy Consumption in Underwater Pan-Tilt Systems
by Shan Tao, Lei Yang, Xiaobo Zhang, Shengya Zhao, Kun Liu, Xinran Tian and Hengxin Xu
Sensors 2025, 25(15), 4785; https://doi.org/10.3390/s25154785 - 3 Aug 2025
Viewed by 32
Abstract
Given the harsh working conditions of underwater pan-tilt systems, their energy consumption management is particularly crucial. This study proposes an underwater pan-tilt operation method with an automatic wake-up mechanism, which activates only upon target detection, replacing conventional timer-based triggering. Furthermore, departing from fixed-duration [...] Read more.
Given the harsh working conditions of underwater pan-tilt systems, their energy consumption management is particularly crucial. This study proposes an underwater pan-tilt operation method with an automatic wake-up mechanism, which activates only upon target detection, replacing conventional timer-based triggering. Furthermore, departing from fixed-duration observation strategies, we introduce a Q-learning algorithm to optimize operational modes. The algorithm dynamically adjusts working modes based on surrounding biological activity frequency: employing a low-power mode (reduced energy consumption with lower monitoring intensity) during periods of sparse biological presence and switching to a high-performance mode (extended observation duration, higher energy consumption, and enhanced monitoring intensity) during frequent biological activity. Simulation results demonstrate that compared to fixed-duration observation schemes, the proposed optimization strategy achieves a 11.11% improvement in monitoring effectiveness while achieving 16.21% energy savings. Full article
(This article belongs to the Section Intelligent Sensors)
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38 pages, 6505 KiB  
Review
Trends in Oil Spill Modeling: A Review of the Literature
by Rodrigo N. Vasconcelos, André T. Cunha Lima, Carlos A. D. Lentini, José Garcia V. Miranda, Luís F. F. de Mendonça, Diego P. Costa, Soltan G. Duverger and Elaine C. B. Cambui
Water 2025, 17(15), 2300; https://doi.org/10.3390/w17152300 - 2 Aug 2025
Viewed by 212
Abstract
Oil spill simulation models are essential for predicting the oil spill behavior and movement in marine environments. In this study, we comprehensively reviewed a large and diverse body of peer-reviewed literature obtained from Scopus and Web of Science. Our initial analysis phase focused [...] Read more.
Oil spill simulation models are essential for predicting the oil spill behavior and movement in marine environments. In this study, we comprehensively reviewed a large and diverse body of peer-reviewed literature obtained from Scopus and Web of Science. Our initial analysis phase focused on examining trends in scientific publications, utilizing the complete dataset derived after systematic screening and database integration. In the second phase, we applied elements of a systematic review to identify and evaluate the most influential contributions in the scientific field of oil spill simulations. Our analysis revealed a steady and accelerating growth of research activity over the past five decades, with a particularly notable expansion in the last two. The field has also experienced a marked increase in collaborative practices, including a rise in international co-authorship and multi-authored contributions, reflecting a more global and interdisciplinary research landscape. We cataloged the key modeling frameworks that have shaped the field from established systems such as OSCAR, OIL-MAP/SIMAP, and GNOME to emerging hybrid and Lagrangian approaches. Hydrodynamic models were consistently central, often integrated with biogeochemical, wave, atmospheric, and oil-spill-specific modules. Environmental variables such as wind, ocean currents, and temperature were frequently used to drive model behavior. Geographically, research has concentrated on ecologically and economically sensitive coastal and marine regions. We conclude that future progress will rely on the real-time integration of high-resolution environmental data streams, the development of machine-learning-based surrogate models to accelerate computations, and the incorporation of advanced biodegradation and weathering mechanisms supported by experimental data. These advancements are expected to enhance the accuracy, responsiveness, and operational value of oil spill modeling tools, supporting environmental monitoring and emergency response. Full article
(This article belongs to the Special Issue Advanced Remote Sensing for Coastal System Monitoring and Management)
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33 pages, 12598 KiB  
Article
OKG-ConvGRU: A Domain Knowledge-Guided Remote Sensing Prediction Framework for Ocean Elements
by Renhao Xiao, Yixiang Chen, Lizhi Miao, Jie Jiang, Donglin Zhang and Zhou Su
Remote Sens. 2025, 17(15), 2679; https://doi.org/10.3390/rs17152679 - 2 Aug 2025
Viewed by 259
Abstract
Accurate prediction of key ocean elements (e.g., chlorophyll-a concentration, sea surface temperature, etc.) is imperative for maintaining marine ecological balance, responding to marine disaster pollution, and promoting the sustainable use of marine resources. Existing spatio-temporal prediction models primarily rely on either physical or [...] Read more.
Accurate prediction of key ocean elements (e.g., chlorophyll-a concentration, sea surface temperature, etc.) is imperative for maintaining marine ecological balance, responding to marine disaster pollution, and promoting the sustainable use of marine resources. Existing spatio-temporal prediction models primarily rely on either physical or data-driven approaches. Physical models are constrained by modeling complexity and parameterization errors, while data-driven models lack interpretability and depend on high-quality data. To address these challenges, this study proposes OKG-ConvGRU, a domain knowledge-guided remote sensing prediction framework for ocean elements. This framework integrates knowledge graphs with the ConvGRU network, leveraging prior knowledge from marine science to enhance the prediction performance of ocean elements in remotely sensed images. Firstly, we construct a spatio-temporal knowledge graph for ocean elements (OKG), followed by semantic embedding representation for its spatial and temporal dimensions. Subsequently, a cross-attention-based feature fusion module (CAFM) is designed to efficiently integrate spatio-temporal multimodal features. Finally, these fused features are incorporated into an enhanced ConvGRU network. For multi-step prediction, we adopt a Seq2Seq architecture combined with a multi-step rolling strategy. Prediction experiments for chlorophyll-a concentration in the eastern seas of China validate the effectiveness of the proposed framework. The results show that, compared to baseline models, OKG-ConvGRU exhibits significant advantages in prediction accuracy, long-term stability, data utilization efficiency, and robustness. This study provides a scientific foundation and technical support for the precise monitoring and sustainable development of marine ecological environments. Full article
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30 pages, 12322 KiB  
Article
Dynamic Modeling and Validation of Dual-Cable Double-Pendulum Systems for Gantry Cranes
by Bowen Jin, Ji Zeng, Pan Gao, He Zhang and Shenwei Ge
Machines 2025, 13(8), 676; https://doi.org/10.3390/machines13080676 - 1 Aug 2025
Viewed by 144
Abstract
This paper presents a novel dynamic modeling framework for gantry crane systems based on the cart double pendulum with dual cables (CDPD) model. The CDPD model systematically incorporates the effects of dual suspension cables, equalizer beams, and closed-chain kinematic constraints, enabling an accurate [...] Read more.
This paper presents a novel dynamic modeling framework for gantry crane systems based on the cart double pendulum with dual cables (CDPD) model. The CDPD model systematically incorporates the effects of dual suspension cables, equalizer beams, and closed-chain kinematic constraints, enabling an accurate simulation of both symmetric and asymmetric lifting scenarios. Utilizing Kane’s method, the model efficiently handles redundant coordinates and holonomic constraints, resulting in a compact and numerically robust formulation. Validation results demonstrate strict energy conservation and consistency with traditional models in limiting cases. The proposed approach provides a unified and extensible foundation for the advanced analysis, control, and optimization of large-scale gantry crane operations. Full article
(This article belongs to the Section Machine Design and Theory)
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27 pages, 6263 KiB  
Article
Revealing the Ecological Security Pattern in China’s Ecological Civilization Demonstration Area
by Xuelong Yang, Haisheng Cai, Xiaomin Zhao and Han Zhang
Land 2025, 14(8), 1560; https://doi.org/10.3390/land14081560 - 29 Jul 2025
Viewed by 224
Abstract
The construction and maintenance of an ecological security pattern (ESP) are important for promoting the regional development of ecological civilizations, realizing sustainable and healthy development, and creating a harmonious and beautiful space for human beings and nature to thrive. Traditional construction methods have [...] Read more.
The construction and maintenance of an ecological security pattern (ESP) are important for promoting the regional development of ecological civilizations, realizing sustainable and healthy development, and creating a harmonious and beautiful space for human beings and nature to thrive. Traditional construction methods have the limitations of a single dimension, a single method, and excessive human subjective intervention for source and corridor identification, without considering the multidimensional quality of the sources and the structural connectivity and resilience optimization of the corridors. Therefore, an ecological civilization demonstration area (Jiangxi Province) was used as the study area, a new research method for ESP was proposed, and an empirical study was conducted. To evaluate ecosystem service (ES) importance–disturbance–risk and extract sustainability sources through the deep embedded clustering–self-organizing map (DEC–SOM) deep unsupervised learning clustering algorithm, ecological networks (ENs) were constructed by applying the minimum cumulative resistance (MCR) gravity model and circuit theory. The ENs were then optimized to improve performance by combining the comparative advantages of the two approaches in terms of structural connectivity and resilience. A comparative analysis of EN performance was constructed among different functional control zones, and the ESP was constructed to include 42 ecological sources, 134 corridors, 210 restoration nodes, and 280 protection nodes. An ESP of ‘1 nucleus, 3 belts, 6 zones, and multiple corridors’ was constructed, and the key restoration components and protection functions were clarified. This study offers a valuable reference for ecological management, protection, and restoration and provides insights into the promotion of harmonious symbiosis between human beings and nature and sustainable regional development. Full article
(This article belongs to the Special Issue Urban Ecological Indicators: Land Use and Coverage)
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25 pages, 16756 KiB  
Article
Research on the Influence of Hydrofoil Propulsive Parameters on Propulsion Efficiency
by Meng Cui, Zhihao Liu, Fei Lu, Jiaye Gong and Zheng Fu
J. Mar. Sci. Eng. 2025, 13(8), 1431; https://doi.org/10.3390/jmse13081431 - 27 Jul 2025
Viewed by 137
Abstract
Oscillating hydrofoils can be used to simplify the study of the swinging caudal fin propulsive mode of fish, where the motion parameters have a direct impact on the hydrodynamic performance and propulsive efficiency. In this study, numerical calculations were carried out on two-dimensional [...] Read more.
Oscillating hydrofoils can be used to simplify the study of the swinging caudal fin propulsive mode of fish, where the motion parameters have a direct impact on the hydrodynamic performance and propulsive efficiency. In this study, numerical calculations were carried out on two-dimensional hydrofoils for sinusoidal and non-sinusoidal heave oscillation, and the numerical results of sinusoidal hydrofoils were compared with the experimental values, which were in good agreement. An analysis of how different motion parameters of the sinusoidal hydrofoil affect the hydrodynamic performance was conducted, and the recommended operating condition range was given in combination with the flow field analysis. A unique non-sinusoidal curve was defined, which can enable the motion to enter the crest and trough earlier or later. The parameters for controlling the degree of non-sinusoidal were also defined. A detailed discussion was carried out on how the non-sinusoidal parameters affect the hydrodynamic performance and the change in the flow field. The corresponding recommended working conditions and application scope were given. Further studies can reveal the propulsive mechanism of the swinging caudal fin and provide a reference for the engineering and design of the next generation of bionic fish. Full article
(This article belongs to the Section Ocean Engineering)
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13 pages, 1599 KiB  
Article
Differential Expression of Hsp100 Gene in Scrippsiella acuminata: Potential Involvement in Life Cycle Transition and Dormancy Maintenance
by Fengting Li, Lixia Shang, Hanying Zou, Chengxing Sun, Zhangxi Hu, Ying Zhong Tang and Yunyan Deng
Diversity 2025, 17(8), 519; https://doi.org/10.3390/d17080519 - 26 Jul 2025
Viewed by 178
Abstract
Protein degradation plays a fundamental role in maintaining protein homeostasis and ensures proper cellular function by regulating protein quality and quantity. Heat shock protein 100 (Hsp100), found in bacteria, plants, and fungi, is a unique chaperone family responsible for rescuing misfolded proteins from [...] Read more.
Protein degradation plays a fundamental role in maintaining protein homeostasis and ensures proper cellular function by regulating protein quality and quantity. Heat shock protein 100 (Hsp100), found in bacteria, plants, and fungi, is a unique chaperone family responsible for rescuing misfolded proteins from aggregated states in an ATP-dependent manner. To date, they are primarily known to mediate heat stress adaptation and enhance cellular survival under extreme conditions in higher plants and algae. Resting cyst formation in dinoflagellates is widely recognized as a response to adverse conditions, which offers an adaptive advantage to endure harsh environmental extremes that are unsuitable for vegetative cell growth and survival. In this study, based on a full-length cDNA sequence, we characterized an Hsp100 gene (SaHsp100) from the cosmopolitan bloom-forming dinoflagellate Scrippsiella acuminata, aiming to examine its life stage-specific expression patterns and preliminarily explore its potential functions. The qPCR results revealed that Hsp100 transcript levels were significantly elevated in newly formed resting cysts compared to vegetative cells and continued to increase during storage under simulated marine sediment conditions (darkness, low temperature, and anoxia). Parallel reaction monitoring (PRM)-based quantification further confirmed that Hsp100 protein levels were significantly higher in resting cysts than in vegetative cells and increased after three months of storage. These findings collectively highlighted the fundamental role of Hsp100 in the alteration of the life cycle and dormancy maintenance of S. acuminata, likely by enhancing stress adaptation and promoting cell survival through participation in proteostasis maintenance, particularly under natural sediment-like conditions that trigger severe abiotic stress. Our work deepens the current understanding of Hsp family members in dinoflagellates, paving the way for future investigations into their ecological relevance within this ecologically significant group. Full article
(This article belongs to the Section Marine Diversity)
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29 pages, 4258 KiB  
Review
Corrosion Performance of Atmospheric Corrosion Resistant Steel Bridges in the Current Climate: A Performance Review
by Nafiseh Ebrahimi, Melina Roshanfar, Mojtaba Momeni and Olga Naboka
Materials 2025, 18(15), 3510; https://doi.org/10.3390/ma18153510 - 26 Jul 2025
Viewed by 490
Abstract
Weathering steel (WS) is widely used in bridge construction due to its high corrosion resistance, durability, and low maintenance requirements. This paper reviews the performance of WS bridges in Canadian climates, focusing on the formation of protective patina, influencing factors, and long-term maintenance [...] Read more.
Weathering steel (WS) is widely used in bridge construction due to its high corrosion resistance, durability, and low maintenance requirements. This paper reviews the performance of WS bridges in Canadian climates, focusing on the formation of protective patina, influencing factors, and long-term maintenance strategies. The protective patina, composed of stable iron oxyhydroxides, develops over time under favorable wet–dry cycles but can be disrupted by environmental aggressors such as chlorides, sulfur dioxide, and prolonged moisture exposure. Key alloying elements like Cu, Cr, Ni, and Nb enhance corrosion resistance, while design considerations—such as drainage optimization and avoidance of crevices—are critical for performance. The study highlights the vulnerability of WS bridges to microenvironments, including de-icing salt exposure, coastal humidity, and debris accumulation. Regular inspections and maintenance, such as debris removal, drainage system upkeep, and targeted cleaning, are essential to mitigate corrosion risks. Climate change exacerbates challenges, with rising temperatures, altered precipitation patterns, and ocean acidification accelerating corrosion in coastal regions. Future research directions include optimizing WS compositions with advanced alloys (e.g., rare earth elements) and integrating climate-resilient design practices. This review highlights the need for a holistic approach combining material science, proactive maintenance, and adaptive design to ensure the longevity of WS bridges in evolving environmental conditions. Full article
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19 pages, 3813 KiB  
Article
Dual Policy–Market Orchestration: New R&D Institutions Bridging Innovation and Entrepreneurship
by Yinhai Fang and Xinping Qiu
Adm. Sci. 2025, 15(8), 289; https://doi.org/10.3390/admsci15080289 - 24 Jul 2025
Viewed by 426
Abstract
This study investigates how new R&D institutions mediate policy–market disjunctures to foster integrated innovation and entrepreneurship ecosystems. Employing a longitudinal case analysis (2013–2023) of the Jiangsu Industrial Technology Research Institute (JITRI), we delineate a three-phase evolutionary process: (1) an initial government-dominated phase, stimulating [...] Read more.
This study investigates how new R&D institutions mediate policy–market disjunctures to foster integrated innovation and entrepreneurship ecosystems. Employing a longitudinal case analysis (2013–2023) of the Jiangsu Industrial Technology Research Institute (JITRI), we delineate a three-phase evolutionary process: (1) an initial government-dominated phase, stimulating foundational capability development through contract R&D; (2) a subsequent marketization phase, enabling systemic resource integration via co-creation centers and global networks; and (3) a culminating synergy phase, where policy–market alignment facilitates ecosystem optimization through crowdsourced R&D and cross-domain collaboration. Three core mechanisms underpin this adaptation: policy–market coupling (providing external momentum), endogenous capability development (absorption to innovation), and dynamic resource orchestration (acquisition to optimization). JITRI’s hybrid governance model demonstrates that stage-contingent interventions—specifically, policy anchoring in early stages followed by market-responsive resource allocation—effectively transmute inherent tensions into productive synergies. These findings yield implementable frameworks for structuring innovative ecosystems and underscore the necessity for comparative studies to establish broader theoretical generalizability. Full article
(This article belongs to the Section International Entrepreneurship)
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28 pages, 4950 KiB  
Article
A Method for Auto Generating a Remote Sensing Building Detection Sample Dataset Based on OpenStreetMap and Bing Maps
by Jiawei Gu, Chen Ji, Houlin Chen, Xiangtian Zheng, Liangbao Jiao and Liang Cheng
Remote Sens. 2025, 17(14), 2534; https://doi.org/10.3390/rs17142534 - 21 Jul 2025
Viewed by 334
Abstract
In remote sensing building detection tasks, data acquisition remains a critical bottleneck that limits both model performance and large-scale deployment. Due to the high cost of manual annotation, limited geographic coverage, and constraints of image acquisition conditions, obtaining large-scale, high-quality labeled datasets remains [...] Read more.
In remote sensing building detection tasks, data acquisition remains a critical bottleneck that limits both model performance and large-scale deployment. Due to the high cost of manual annotation, limited geographic coverage, and constraints of image acquisition conditions, obtaining large-scale, high-quality labeled datasets remains a significant challenge. To address this issue, this study proposes an automatic semantic labeling framework for remote sensing imagery. The framework leverages geospatial vector data provided by OpenStreetMap, precisely aligns it with high-resolution satellite imagery from Bing Maps through projection transformation, and incorporates a quality-aware sample filtering strategy to automatically generate accurate annotations for building detection. The resulting dataset comprises 36,647 samples, covering buildings in both urban and suburban areas across multiple cities. To evaluate its effectiveness, we selected three publicly available datasets—WHU, INRIA, and DZU—and conducted three types of experiments using the following four representative object detection models: SSD, Faster R-CNN, DETR, and YOLOv11s. The experiments include benchmark performance evaluation, input perturbation robustness testing, and cross-dataset generalization analysis. Results show that our dataset achieved a mAP at 0.5 intersection over union of up to 93.2%, with a precision of 89.4% and a recall of 90.6%, outperforming the open-source benchmarks across all four models. Furthermore, when simulating real-world noise in satellite image acquisition—such as motion blur and brightness variation—our dataset maintained a mean average precision of 90.4% under the most severe perturbation, indicating strong robustness. In addition, it demonstrated superior cross-dataset stability compared to the benchmarks. Finally, comparative experiments conducted on public test areas further validated the effectiveness and reliability of the proposed annotation framework. Full article
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10 pages, 3839 KiB  
Article
Sound Production Characteristics of the Chorus Produced by Small Yellow Croaker (Larimichthys polyactis) in Coastal Cage Aquaculture
by Young Geul Yoon, Hansoo Kim, Sungho Cho, Sunhyo Kim, Yun-Hwan Jung and Donhyug Kang
J. Mar. Sci. Eng. 2025, 13(7), 1380; https://doi.org/10.3390/jmse13071380 - 21 Jul 2025
Viewed by 294
Abstract
Recent advances in passive acoustic monitoring (PAM) have markedly improved the ability to study marine soundscapes by enabling long-term, non-invasive monitoring of biological sounds across large spatial and temporal scales. Among aquatic organisms, fish are primary contributors to biophony, producing sounds associated with [...] Read more.
Recent advances in passive acoustic monitoring (PAM) have markedly improved the ability to study marine soundscapes by enabling long-term, non-invasive monitoring of biological sounds across large spatial and temporal scales. Among aquatic organisms, fish are primary contributors to biophony, producing sounds associated with feeding, reproduction, and social behavior. However, the majority of previous research has focused on individual vocalizations, with limited attention to collective acoustic phenomena such as fish choruses. This study quantitatively analyzes choruses produced by the small yellow croaker (Larimichthys polyactis), an ecologically and commercially important species in the Northwest Pacific Ocean. Using power spectral density (PSD) analysis, we examined long-term underwater recordings from a sea cage containing approximately 2000 adult small yellow croakers. The choruses were centered around ~600 Hz and exhibited sound pressure levels 15–20 dB higher at night than during the day. These findings highlight the ecological relevance of fish choruses and support their potential use as indicators of biological activity. This study lays the foundation for incorporating fish choruses into soundscape-based PAM frameworks to enhance biodiversity and habitat monitoring. Full article
(This article belongs to the Special Issue Advanced Research in Marine Environmental and Fisheries Acoustics)
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17 pages, 9561 KiB  
Article
Magnetic Data Correction for Fluxgate Magnetometers on a Paramagnetic Unmanned Surface Vehicle: A Comparative Analysis in Marine Surveys
by Seonggyu Choi, Mijeong Kim, Yosup Park, Gidon Moon and Hanjin Choe
Sensors 2025, 25(14), 4511; https://doi.org/10.3390/s25144511 - 21 Jul 2025
Viewed by 333
Abstract
Unmanned Surface Vehicle (USV) offers a cost-effective platform for high-resolution marine magnetic surveys using shipborne fluxgate magnetometers. However, platform-induced magnetic interference and electromagnetic interference (EMI) can degrade data quality, even with paramagnetic hulls. This study evaluates fluxgate magnetometer data acquired from a paramagnetic-hulled [...] Read more.
Unmanned Surface Vehicle (USV) offers a cost-effective platform for high-resolution marine magnetic surveys using shipborne fluxgate magnetometers. However, platform-induced magnetic interference and electromagnetic interference (EMI) can degrade data quality, even with paramagnetic hulls. This study evaluates fluxgate magnetometer data acquired from a paramagnetic-hulled USV. Noise characterization identified EMI and maneuver-induced high-frequency noise, the latter of which was effectively reduced through low-pass filtering. We compared four different correction approaches addressing both vessel attitude and magnetization. The results demonstrate that the paramagnetic hull significantly reduces magnetic interference and shortens the duration of viscous magnetization (VM) effects caused by eddy currents in the platform, compared to conventional ferromagnetic vessels. Nonetheless, residual magnetization from onboard ferromagnetic components still requires correction. A method utilizing all nine components of the susceptibility tensor demonstrated improved accuracy and stability. Despite corrections, low-frequency VM-related noise during azimuth changes and a consistent absolute offset (~200 nT) remain when compared to towed scalar magnetometer data. These findings validate the use of paramagnetic USV for vector magnetic surveys, highlighting their benefit in VM mitigation while emphasizing the need for further development in VM correction and offset correction to achieve high-precision measurements. Full article
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25 pages, 17002 KiB  
Article
Study on Hydrodynamic and Cavitation Characteristics of Two-Element Hydrofoil Systems for Fully Submerged Hydrofoil Craft: Influence Analysis of Key Geometric Parameters
by Meishen Yu, Hongyu Li, Yu Zhang, Qunhong Tian, Shaobo Yang, Zongsheng Wang and Weizhuang Ma
J. Mar. Sci. Eng. 2025, 13(7), 1378; https://doi.org/10.3390/jmse13071378 - 20 Jul 2025
Viewed by 289
Abstract
This study investigates the effects of key geometric parameters on the hydrodynamic and cavitation characteristics of two-element hydrofoil systems for fully submerged unmanned hydrofoil craft, aiming to solve their active stabilization problems. Using STARCCM+ software, the RANS method, and the SST k-ω turbulence [...] Read more.
This study investigates the effects of key geometric parameters on the hydrodynamic and cavitation characteristics of two-element hydrofoil systems for fully submerged unmanned hydrofoil craft, aiming to solve their active stabilization problems. Using STARCCM+ software, the RANS method, and the SST k-ω turbulence model, the research analyzes the impacts of flap deflection angle (α), main wing-to-flap chord ratio (c1/c2), and spacing (g). Results show that when the spacing is fixed, increasing the chord ratio reduces the lift and drag coefficients. When the chord ratio is fixed, increasing the spacing causes the lift and drag coefficients to first rise and then fall. With increasing flap deflection angle (α), cavitation intensifies, but it can be suppressed by increasing the chord ratio, reaching a minimum at g = 2.4%c1. The optimal configuration is c1/c2 = 1.5 and g = 2.4%c1, which can balance the lift–drag performance and anti-cavitation capability. This study provides a scientific basis for solving the active stabilization problems of fully submerged unmanned hydrofoil craft and insights for enhancing their seakeeping performance. Full article
(This article belongs to the Special Issue CFD Applications in Ship and Offshore Hydrodynamics 2nd Edition)
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