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Articles 31 - 60 of 484

Full-Text Articles in Fresh Water Studies

Enhancing Underwater Imagery And Organism Detection Using Reinforcement Learning, K. Arul Deepa, P. Ramya, Karpaga Vinodha, Dharmaraja C Jan 2026

Enhancing Underwater Imagery And Organism Detection Using Reinforcement Learning, K. Arul Deepa, P. Ramya, Karpaga Vinodha, Dharmaraja C

Journal of Marine Science and Technology–Taiwan

Underwater environments pose significant challenges in assessing image quality and organism detection due to light scattering and absorption, which limits visibility and color fidelity. Existing solutions often fail to effectively address these challenges, resulting in suboptimal image quality and hindering organism identification. This paper examines the problem through a dual-focused approach: enhancing underwater images and detecting organisms using the Underwater Image Enhancement Benchmark (UIEB) dataset. The first step introduces a state-of-the-art method for image enhancement by applying reinforcement learning (RL) principles. By formulating the enhancement process as a Markov Decision Process (MDP)—where states are represented by image features and actions …


An Integrated Modeling Framework To Evaluate Circularity Of The Corn–Water–Ethanol–Beef Nexus, Heydi Han Dec 2025

An Integrated Modeling Framework To Evaluate Circularity Of The Corn–Water–Ethanol–Beef Nexus, Heydi Han

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This dissertation examines the transition from conventional linear agricultural and food bioenergy systems toward more circular, resilient, and resource-efficient configurations. Prior research indicates that spatial and temporal variability in soil, weather, animal biological responses, and management decisions strongly influences productivity, nutrient-use efficiency, and profitability. Studies have also shown that a diversified circular system can buffer these sources of variability, improving stability and adaptive capacity. Building on these insights, the central focus of this work is to develop an integrated modeling framework to evaluate circularity within the Corn-Water-Ethanol-Beef (CWEB) nexus and explore how climate variability and management choices shape system-wide performance. …


Occurrence Of Per And Polyfluoroalkyl Substances In Rural Wastewater Treatment Plants And Comparison To Large Treatments Plants, Madeleine Rauhauser Dec 2025

Occurrence Of Per And Polyfluoroalkyl Substances In Rural Wastewater Treatment Plants And Comparison To Large Treatments Plants, Madeleine Rauhauser

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Per and polyfluoroalkyl substances (PFAS) are a class of compounds defined by their carbon – fluorine bonds, which are incredibly strong. The strength of this bond makes these compounds very useful industrially, they are used as waterproof and grease proof coatings, and as fire retardants. The same thing that makes them useful industrially makes them incredibly recalcitrant in the environment, it is difficult to destroy these compounds. PFAS are also suspected to cause health impacts in people, such as kidney cancer and low birth weights. Wastewater has been commonly identified as a contributor to the amount of PFAS in the …


Evaluation Of Performance Characteristics And Groundwater Contamination Risks Associated With On-Farm Swine Carcass Disposal Via Composting And Shallow Burial With Carbon, Gustavo Castro Garcia Aug 2025

Evaluation Of Performance Characteristics And Groundwater Contamination Risks Associated With On-Farm Swine Carcass Disposal Via Composting And Shallow Burial With Carbon, Gustavo Castro Garcia

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This dissertation evaluates the performance of three on-farm swine carcass disposal methods: whole carcass composting (WCC), ground carcass composting (GCC), and shallow burial with carbon (SBC), focusing on biosecurity factors and groundwater contamination risks. Foreign animal diseases (FADs), such as African swine fever and classical swine fever, pose severe economic and animal well-being risks if introduced to the United States. With confirmation of an FAD, swine movement will be halted, creating an urgent need for practical, biosecure, and environmentally responsible on-farm disposal strategies for swine carcasses. Nebraska, as a leading swine-producing state, exemplifies the vulnerability of high-density livestock regions to …


Drift Dynamics Of Early Life-Stage Invasive Carps, Saurav Karki Aug 2025

Drift Dynamics Of Early Life-Stage Invasive Carps, Saurav Karki

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Asian carp species pose significant ecological threats to North American freshwater systems due to their invasive nature and prolific reproduction. Their semi buoyant eggs develop while drifting downstream with the river current. Understanding early life-stage transport is therefore critical for predicting recruitment potential and guiding management efforts. Existing fluvial egg drift models, including those relying on 1-D hydraulics and fully 3-D CFD-based models, are either inadequate for complex braided rivers or too computationally demanding for large-scale application. The Platte River in Nebraska, characterized by wide, shallow, multi-threaded channels, is dominated by two-dimensional flow conditions, making a depth-averaged 2-D modeling approach …


Response Of Soybean To Variable Irrigation Levels In Eastern Nebraska Using The Aquacrop Model, Anmol Singh Jul 2025

Response Of Soybean To Variable Irrigation Levels In Eastern Nebraska Using The Aquacrop Model, Anmol Singh

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

AquaCrop was calibrated and validated for soybean [Glycine max (L.) Merr.] using 19 irrigation treatments from five years using data from field experiments. The model accurately simulated canopy cover (CC), soil water content (SWC), and grain yield, with overall validation nRMSE values of 12%, 7%, and 7%, respectively. The overall validation nRMSE for SWC in individual 30-cm soil layers was comparatively higher, at 19%. The model was subsequently applied for long-term simulations (2010–2024) to estimate soybean yield and water requirements for two dominant soil types, Yutan silty clay loam and Tomek silt loam under three irrigation levels - rainfed, …


Optimizing Nitrogen Management: Assessing Nitrate Transport In The Deep Vadose Zone And Its Impact On Groundwater Quality In East-Central Nebraska, Muili O. Lawal May 2025

Optimizing Nitrogen Management: Assessing Nitrate Transport In The Deep Vadose Zone And Its Impact On Groundwater Quality In East-Central Nebraska, Muili O. Lawal

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Groundwater contamination by nitrate (NO₃-N) is a growing environmental and public health concern driven largely by intensive agricultural fertilizer applications. The vadose zone plays an important role in NO₃-N transport, influencing groundwater quality and agricultural sustainability. This study investigated NO₃-N leaching dynamics in the deep vadose zone of Water Quality Sub-Area 30 (WQA30) within the Lower Loup Natural Resources District (LLNRD), northeast of Columbus, Nebraska (mean groundwater NO₃-N: 20.3 mg/L), using soil cores from 16 shallow (to 6.1 m) and four deep (down to 25.9 m) across four zones, two with inorganic fertilizer (Zones 1 and 4) and two with …


Towards Advancing Streamflow And Peak Flow Prediction With Machine Learning: Identifying Infrastructure At Risk, Sudan Pokharel May 2025

Towards Advancing Streamflow And Peak Flow Prediction With Machine Learning: Identifying Infrastructure At Risk, Sudan Pokharel

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Due to climate change and its impact, the need for adaptive strategies for natural disaster mitigation and resource management has never been more urgent. Central to this is water resource management, which is essential for sustainable human activities, ecological balance, and the mitigation of natural hazards like floods. Streamflow is a crucial element of water resource management and plays a vital role in planning and building water infrastructure, implementing emergency response plans, supporting flood mitigation initiatives, and regulating agricultural and industrial use. However, accurate prediction of streamflow still remains a challenge due to the complex non-linear and non-stationary interaction between …


Study On Motion Prediction Analysis Of Large Vessels Entering Kaohsiung Port Second Harbor, Li-Heng Cheng, Hsing-Yu Wang Jan 2025

Study On Motion Prediction Analysis Of Large Vessels Entering Kaohsiung Port Second Harbor, Li-Heng Cheng, Hsing-Yu Wang

Journal of Marine Science and Technology–Taiwan

Pilotage is a primary service offered by ports, ensuring the safe passage of entering and exiting vessels. This study applied motion prediction analysis to large vessels navigating the constrained waterways of Kaohsiung Port’s second harbor. To address the needs of pilots and port operators, a simplified planar motion equation was developed that incorporated speed over ground and rate of turn (ROT) as primary variables. The model relied on inputs of limited navigational data, enabling pilots to predict changes in heading and position over time and determine the conditions for safe harbor entry. Vessel paths and turning angles were analyzed to …


Using Post-Supercritical Co2-Assisted Method To Deposit Niep Alloy Coating On The Micro-Arc Oxidation Layer Of Az31 Magnesium Alloy And Its Corrosion Behavior Analysis, Kang-Yu Liao, Hung-Hua Sheu, Ming-Yuan Lin, Ming-Chih Kuo, Po-Hsun Wu, Hung-Bin Lee Jan 2025

Using Post-Supercritical Co2-Assisted Method To Deposit Niep Alloy Coating On The Micro-Arc Oxidation Layer Of Az31 Magnesium Alloy And Its Corrosion Behavior Analysis, Kang-Yu Liao, Hung-Hua Sheu, Ming-Yuan Lin, Ming-Chih Kuo, Po-Hsun Wu, Hung-Bin Lee

Journal of Marine Science and Technology–Taiwan

In this study, a Ni-P alloy coating was deposited on the micro arc oxidation (MAO) layer of AZ31 magnesium alloy to improve its corrosion resistance. The MAO layers were prepared under different operated voltages from 300 to 400 V. The results indicated that the optimize operated parameters for MAO layer is at 350 V, the MAO coatings had the most compact microstructure and superior corrosion resistance. In order to improve the corrosion resistance of MAO coating, this study chose to deposit Ni-P alloy coating on the surface of MAO coating via the post supercritical CO2-assisted electroless plating (PSC-CO …


The Effect Of Feedback On A Remote Operator’S Maneuvering Control For Mass Remote Navigation Competency, Hyoseon Hwang, Ik-Hyun Youn Jan 2025

The Effect Of Feedback On A Remote Operator’S Maneuvering Control For Mass Remote Navigation Competency, Hyoseon Hwang, Ik-Hyun Youn

Journal of Marine Science and Technology–Taiwan

The rapid advancement of Maritime Autonomous Surface Ships (MASS) technology has highlighted the growing need for Remote Operators (ROs) to manage MASS effectively. ROs possess specialized competencies in areas such as situational awareness, crisis management, and system operation. Despite the introduction of competency-based training and assessment in the maritime sector through the international convention on standards of training, certification, and watchkeeping for seafarers convention, the framework's implementation remains incomplete, particularly in remote operator training for MASS. This study is purpose to identify which competencies improve rapidly with performance feedback and which improve slowly. This study conducted an experiment to quantitatively …


Evaluation Of Carbon Sequestration In Seagrass Meadows Of Kenting: A Comparative Study With Penghu And Dongsha Island, Zih-Wei Tang, Huei-Fen Chen, Jordi Mahardika Puntu, Ping-Yu Chang, Li Lo, Jian-Jhih Chen, Wen-Chen Chou, Lan-Feng Fan, Ying-Ju Chang Jan 2025

Evaluation Of Carbon Sequestration In Seagrass Meadows Of Kenting: A Comparative Study With Penghu And Dongsha Island, Zih-Wei Tang, Huei-Fen Chen, Jordi Mahardika Puntu, Ping-Yu Chang, Li Lo, Jian-Jhih Chen, Wen-Chen Chou, Lan-Feng Fan, Ying-Ju Chang

Journal of Marine Science and Technology–Taiwan

This study investigates the controlling factors of carbon sequestration (CS) in seagrass bed sediments across three distinct environments in Taiwan: the Kenting (KT) coastal area, the Penghu (PH) open inner bay, and the Dongsha (DS) Atoll lagoon. Actual measurements of the substrate depth beneath the sediment and ground-penetrating radar (GPR) scans of the beach reveal that the coral reef bedrock in KT slopes landward. A field survey of the seagrass area in KT was conducted, and three cross-sectional profiles were analyzed to determine their topography, yielding a median sediment thickness of 88.2cm. Based on these measurements, the sediment volume was …


Calculation Of Aquifer Transmissivity From Borehole Resistance Measurements And Pumping Test Results, Fen-Rong Yang, Chien-Wei Huang, Tien-Kuen Huang Jan 2025

Calculation Of Aquifer Transmissivity From Borehole Resistance Measurements And Pumping Test Results, Fen-Rong Yang, Chien-Wei Huang, Tien-Kuen Huang

Journal of Marine Science and Technology–Taiwan

Transmissivity is a crucial hydrogeological parameter for evaluating groundwater resources. This parameter is conventionally evaluated using pumping tests; however, these tests are costly and can be conducted at few sites. Many researchers have used ground resistance and pumping test data to estimate various hydrogeological parameters. In this study, borehole resistance survey and pumping test data collected by the Taiwan Groundwater Monitoring Network were used to establish the relationship between transmissivity and formation factor for aquifers in the Zhuoshui River alluvial fan. This relationship was then used to estimate the water output of the aforementioned aquifers in a cost-effective manner from …


A Neural Network-Based Sliding Mode Adaptive Control System For Unmanned Surface Vehicles, Sun Qiaomei, An Liang, Jiang Linglin Jan 2025

A Neural Network-Based Sliding Mode Adaptive Control System For Unmanned Surface Vehicles, Sun Qiaomei, An Liang, Jiang Linglin

Journal of Marine Science and Technology–Taiwan

Over the past decades, numerous studies have explored the use of autonomous unmanned surface vehicles (USVs). Successful USV operation requires a robust tracking control system to perform a range of tasks. However, USV dynamics are uncertain, time-varying, and nonlinear. This paper presents a neural network-based sliding mode adaptive control (NNSMAC) system to enhance USV tracking performance. Trajectories were generated using spline and polynomial interpolation based on a set of N predefined waypoints. Simulation results show that the proposed method outperforms traditional sliding mode control in error reduction, enabling more effective tracking.


Evaluation Of Practical Methods To Determine If A Karst Creek Is Gaining Or Losing: Case Study Of Leith Creek, Elizabeth Jones Jan 2025

Evaluation Of Practical Methods To Determine If A Karst Creek Is Gaining Or Losing: Case Study Of Leith Creek, Elizabeth Jones

Graduate Theses/Dissertations

Karst landscapes are abundant in Missouri, with features such as caves, springs, and sinkholes that form through the dissolution of limestone. Leith Creek is a small stream in Polk County, Missouri fed by two springs and the shallow unconfined Springfield Plateau aquifer, a highly karstified aquifer which is made up of limestone and minor interbedded shale-mudstone units. To determine if Leith Creek is gaining or losing, stream flow, water chemistry and temperature sensors were monitored. Stream flow results required multiple visits to take measurements while temperature sensors required two visits, one to install the dataloggers and another to remove the …


Foreign Object Detection System Development Using Edge Devices Integrated With Quadcopter Autonomous Tracking, Chi-Chia Huang, Ching-Hung Lee Jan 2025

Foreign Object Detection System Development Using Edge Devices Integrated With Quadcopter Autonomous Tracking, Chi-Chia Huang, Ching-Hung Lee

Journal of Marine Science and Technology–Taiwan

This study proposes an all-weather autonomous foreign-object detection system capable of operating in low-light environments. We used a highly mobile quadcopter equipped with an edge-computing device as the inspection platform. On the software side, we integrated a low-light image enhancement model, a path-tracking algorithm, and a foreign object detection model to achieve rapid object detection. A lightweight, low-light image-enhancement model reduces the need for additional lighting equipment, thereby enabling reliable detection under low-light conditions. The path-tracking algorithm integrates a lightweight semantic segmentation model with traditional image-processing techniques to establish flight paths efficiently and reliably. The foreign-object detection component employs state-of-the-art …


Optimization Of Underactuated Ship Sliding Mode Controller Based On The Ddpg Algorithm, Lin Ma, Mingzhe Qi, Shicai Chen, Hongwei Bian, Jian Zhang Jan 2025

Optimization Of Underactuated Ship Sliding Mode Controller Based On The Ddpg Algorithm, Lin Ma, Mingzhe Qi, Shicai Chen, Hongwei Bian, Jian Zhang

Journal of Marine Science and Technology–Taiwan

Due to the development of ship intelligence, the demand for precise controllers is increasing day by day. In traditional design, the trial-and-error method often leads to the use of inaccurate controller parameters, causing oscillations when environmental disturbances are present. To address these issues, this study introduces deep learning to optimize the controller parameters, particularly those used for sliding mode controllers in underactuated ships. We adopt the Deep Deterministic Policy Gradient (DDPG) algorithm based on the Actor Critic framework. By freely setting the reward function to match the control objective, the trained model can output more accurate controller parameters, with the …


Experiments On Aluminum Alloy Additive Layer Waam Lamination Using The Arc Current Reduction Technique, Jukkapun Greebmalai, Eakkachai Warinsiriruk, Chao-Hsiang Hsiao, Yin-Tien Wang Jan 2025

Experiments On Aluminum Alloy Additive Layer Waam Lamination Using The Arc Current Reduction Technique, Jukkapun Greebmalai, Eakkachai Warinsiriruk, Chao-Hsiang Hsiao, Yin-Tien Wang

Journal of Marine Science and Technology–Taiwan

Recent advancements in additive manufacturing have been propelled by innovations in processes, materials, and fabrication techniques. This study specifically focuses on the optimizing Wire and Arc Additive Manufacturing (WAAM) within the Gas Metal Arc Welding (GMAW) process. The goal is to build laminated layers using aluminum alloy from the five-thousand series. In this research, a novel technique is introduced that employs a reduced arc-current during the additive layer progress for aluminum alloys, along with a double pulse current in the GMAW process to enhance weldability. The material used for addition is ER5356 aluminum wire, which is applied to an Al-5083 …


An Optimization Model For Supporting Bunkering Decisions In Bulk Shipping, Chung-Cheng Lu, Hui-Chieh Li, Hung-Yu Chen Jan 2025

An Optimization Model For Supporting Bunkering Decisions In Bulk Shipping, Chung-Cheng Lu, Hui-Chieh Li, Hung-Yu Chen

Journal of Marine Science and Technology–Taiwan

This study addresses a bunkering optimization problem for bulk shipping carriers that explores route deviation to find optimal bunkering locations and amounts. A mixed integer linear programming (MILP) model is developed to determine optimal bunkering decisions that minimize total operating costs, including total daily operating costs, bunkering costs, port charges and surcharges, while observing time window constraints at loading/unloading ports. The proposed model is evaluated using instances generated from real data provided by H company with its operational headquarters in Taipei, Taiwan, which operates a fleet of handysize ships in East and South Asia. The results indicate that optimization models …


Assessment Of Coastal Navigation Safety: A Case Study Of Boka Bay With Stakeholder Perspectives, Ivan Mraković, Rino Bošnjak Jan 2025

Assessment Of Coastal Navigation Safety: A Case Study Of Boka Bay With Stakeholder Perspectives, Ivan Mraković, Rino Bošnjak

Journal of Marine Science and Technology–Taiwan

The navigational safety of Boka Bay, i.e., a critical maritime area along the Adriatic coast, is of great importance owing to its ecological sensitivity, diverse marine traffic, and significant economic activity. This study provides a comprehensive assessment by analyzing the perspectives of various stakeholders, including seafarers, local pilots, skippers, regulatory authorities, and others engaged in maritime activities within the bay. Using a structured questionnaire survey, both quantitative and qualitative data were collected in formats such as descriptive responses, Yes/No choices, and Likert scale ratings, ensuring a well-rounded understanding of navigational practices and challenges. The data were analyzed using descriptive statistics, …


A Hybrid Model To Assess Commercial Port Resilience In Taiwan, Po-Hsing Tseng, James J.H. Liou Jan 2025

A Hybrid Model To Assess Commercial Port Resilience In Taiwan, Po-Hsing Tseng, James J.H. Liou

Journal of Marine Science and Technology–Taiwan

Since 2021, international commercial ports have faced unprecedented challenges (e.g., COVID-19 pandemic, Suez Canal congestion), impacting daily life, work, human well-being, properties, the environment, and socio-economic activities. The adaptation capability resilience of international commercial ports to respond to external changes has become crucial. This study develops an expert knowledge-based hybrid multi-criteria decision-making model integrating Best-Worst Method (BWM), Rough Dombi Aggregator, and Combined Compromise Solution (CoCoSo) to evaluate port resilience capabilities, using Taiwan's international commercial ports as a case study. We propose four evaluation dimensions encompassing 13 indicators: detection capability, resistance capability, resource integration capability, and recovery capability. The BWM determined …


An Evaluation Of The Possibility And Effectiveness Of Renewable Energy In Container Terminal At Jinhae New Port, Min-Seop Sim, Yul-Seong Kim, Chang-Hee Lee Jan 2025

An Evaluation Of The Possibility And Effectiveness Of Renewable Energy In Container Terminal At Jinhae New Port, Min-Seop Sim, Yul-Seong Kim, Chang-Hee Lee

Journal of Marine Science and Technology–Taiwan

The international goals of combating climate change and reducing greenhouse gas emissions are driving container terminal operators to adopt renewable energy solutions. This study evaluated the feasibility and effectiveness of introducing renewable energy and eco-fuels for energy independence at the Jinhae New Port Container Terminal, South Korea. Using portfolio analysis, eight renewable energy technologies (solar power, solar thermal energy, wind energy, hydropower, marine energy, geothermal energy, bioenergy, and waste-to-energy) and seven eco-friendly fuels (electricity, liquefied natural gas, liquefied petroleum gas, hydrogen fuel cells, ammonia fuel cells, bioenergy, and hybrid systems) were assessed. Survey data from stakeholders identified solar, wind, and …


Numerical Simulation Of The Fracture Resistance Of A Flame Deflector Under Impact And High Temperature By Using The Extended Finite-Element Method, Guangzhong Liu, Yuqing Feng, Tong Lin, Zhixin Xiong, Zhenting Chen Jan 2025

Numerical Simulation Of The Fracture Resistance Of A Flame Deflector Under Impact And High Temperature By Using The Extended Finite-Element Method, Guangzhong Liu, Yuqing Feng, Tong Lin, Zhixin Xiong, Zhenting Chen

Journal of Marine Science and Technology–Taiwan

During the launch of rockets at sea, the flame deflector of the launch platform is subject to transient impact loads and high temperatures, which can result in the fracturing of the flame deflector, thereby endangering the platform and launch safety. In this study, dynamic crack propagation in a flame deflector under the aforementioned conditions was numerically investigated using the extended finite-element method (XFEM). The bulk of the flame deflector was modeled using shell elements, the local area in which the crack evolves was modeled using solid elements, and discontinuities were modeled using enrichment functions in the XFEM. The degrees of …


Overseas Agent Selection For International Logistics Companies: A Case Study, Hung-Ta Lin, Hua-An Lu Jan 2025

Overseas Agent Selection For International Logistics Companies: A Case Study, Hung-Ta Lin, Hua-An Lu

Journal of Marine Science and Technology–Taiwan

International logistics companies (ILCs) have aggressively participated in the supply chain systems of production industries as part of global trade development. They have adopted diversified and multinational models by expanding their overseas services to align with the various characteristics of regional economic patterns. Assigning specific local agents for their forwarding operations has been one of the key strategies for overseas services. Notably, the performance of these selected agents has significantly influenced service quality in their respective regions. In collaboration with the top management of an ILC, this study proposes an evaluation framework comprising 4 criteria and 16 subcriteria for selecting …


Cfrp Retrofitting For Enhancing Damping In Cushion Mounts For Marine Applications, Chih-Lung Hou, Guang-Min Luo, Sheng-Yuan Chen Jan 2025

Cfrp Retrofitting For Enhancing Damping In Cushion Mounts For Marine Applications, Chih-Lung Hou, Guang-Min Luo, Sheng-Yuan Chen

Journal of Marine Science and Technology–Taiwan

Reducing vibration transmission and dynamic response is critical for data processing devices, precision instruments, and machinery in environments with frequent shocks, such as naval applications. These devices are often mounted to ships with cushion mounts. This study presents a cost-effective and rapid method for retrofitting mounts with carbon fiber reinforced polymers; the method greatly improved damping and effectively reduced vibration transmission. Specimens were produced and subjected to experimental modal analysis, and finite element models were developed for comparison. The frequency response functions and modes of the structural components from both methods were compared to assess the improvement in the damping …


Application Of Genetic Algorithm In Container Vessel Stowage Planning With Carbon Tax Considerations, Ming-Feng Yang, Wei-Hao Su, Ko-Meng Hu, Yu-Hsuan Li Jan 2025

Application Of Genetic Algorithm In Container Vessel Stowage Planning With Carbon Tax Considerations, Ming-Feng Yang, Wei-Hao Su, Ko-Meng Hu, Yu-Hsuan Li

Journal of Marine Science and Technology–Taiwan

This study developed a method for optimizing stowage planning for container vessels, a crucial aspect of international trade logistics. Over 80% of global trade depends on containerized transportation; thus, effective stowage planning is essential for minimizing transportation costs and enhancing operational efficiency. In the proposed hybrid optimization approach, integer programming is combined with a genetic algorithm to generate optimal stowage plans. The key factors considered in this method include load capacity limits, stacking constraints, and carbon tax regulations. The proposed method involves maximizing space utilization while minimizing logistics costs, with particular emphasis on reducing port dwell times. The findings of …


Research On Multi-Ship Collision Avoidance Decision-Making Based On Improved Velocity Obstacle Method Using Dynamic Elliptical Ship Domains, Tang Xinwei, Li Weifeng Jan 2025

Research On Multi-Ship Collision Avoidance Decision-Making Based On Improved Velocity Obstacle Method Using Dynamic Elliptical Ship Domains, Tang Xinwei, Li Weifeng

Journal of Marine Science and Technology–Taiwan

The velocity obstacle method offers collision avoidance solutions for critical multi-ship encounter scenarios. This thesis introduces a Reciprocal Velocity Obstacle (RVO) approach based on dynamic elliptical ship domains for multi-ship collision avoidance. Initially, the concept of dynamic elliptical ship domains is presented, building upon the original static elliptical ship domain Velocity Obstacle (VO) method. Subsequently, multi-ship encounter scenarios are simulated in both virtual environments and real nautical charts, comparing the two methods. The analysis results demonstrate the improved method's excellent performance in both cases, underscoring its advantages. This research provides more effective collision avoidance strategies for multi-ship encounters.


Exploring The Red Sea Crisis’S Supply Chain Disruption Impacts On The Shipping Industry, Po-Hsing Tseng, Nick Pilcher Jan 2025

Exploring The Red Sea Crisis’S Supply Chain Disruption Impacts On The Shipping Industry, Po-Hsing Tseng, Nick Pilcher

Journal of Marine Science and Technology–Taiwan

Since October 7, 2023, the Houthi militia in Yemen has continuously attacked Israel and its nearby ships in the Red Sea. This crisis has impacted on global ship operations, freight rates, and shipping networks, since this conflict seriously affects the international trade between Europe and Asia and brings many unpredictable butterfly effects (e.g. supply chain disruption, and high transportation costs in shipping and air cargo). This papero explores its impact on the supply chain and suggests potential solutions;, and to consider perceptions on who should be responsible for the crisis, and who will actually shoulder the responsibility for the crisis. …


Dna Barcoding In Species Identification Of Flying Fish (Exocoetidae) And Halfbeaks (Hemiramphidae) Larvae: A Comparative Study Of The Database Over A Decade, Hui-Ling Ko, Kwang-Tsao Shao, Ching-Yi Chen, Yen-Wei Chang Jan 2025

Dna Barcoding In Species Identification Of Flying Fish (Exocoetidae) And Halfbeaks (Hemiramphidae) Larvae: A Comparative Study Of The Database Over A Decade, Hui-Ling Ko, Kwang-Tsao Shao, Ching-Yi Chen, Yen-Wei Chang

Journal of Marine Science and Technology–Taiwan

The families Exocoetidae and Hemiramphidae comprise migratory species, whose identification based on their external morphological characteristics can be challenging because of their similarities. DNA barcoding has been used in taxonomic and evolutionary studies to address these issues. The morphological characteristics of fish larvae change rapidly and often lack distinctive features, posing a challenge for species-level identification. This study used DNA barcoding to identify flying fish and half-beaked larvae. Using plankton nets, sampling was conducted seasonally between 2010 and 2013 in Nanwan, Taiwan. A total of 903 individuals were collected, of which 111 were identified as flying and half-beaked fish based …


Operational Risk Evaluation Of Oil Tankers Via Multivariate Gaidai Reliability Framework Incorporating Memory Effects, Oleg Gaidai, Shicheng He, Jinlu Sheng, Yan Zhu, Alaa Elsayed, Mahmoud El-Wazery Jan 2025

Operational Risk Evaluation Of Oil Tankers Via Multivariate Gaidai Reliability Framework Incorporating Memory Effects, Oleg Gaidai, Shicheng He, Jinlu Sheng, Yan Zhu, Alaa Elsayed, Mahmoud El-Wazery

Journal of Marine Science and Technology–Taiwan

The retreat of Arctic Sea ice may exert a major impact on economy,potentially transforming the nature of commerce between Asia, Europe, and the Americas. Projections indicate a 40% reduction in transit distance and a 30% decrease in voyage time between Europe and northwest Asia compared to traditional routes such as the Suez Canal. However, even during summer navigation, fragmented floating ice persists, generating stochastic ice loads on vessel bows and hulls through complex ship-to-ice interaction. For structural design, statistical extrapolation methods are required to accurately assess excessive areal bow/hull stresses. This study proposes a novel multi-modal structural damage risk assessment …