Context-Dependent Data-Envelopment-Analysis-Based Efficiency Evaluation Of Coastal Ports In China Based On Social Network Analysis,
2023
School of Business, Nanjing Audit University, Nanjing 211815, Nanjing, P.R. China
Context-Dependent Data-Envelopment-Analysis-Based Efficiency Evaluation Of Coastal Ports In China Based On Social Network Analysis, Yu Yu, Dai-Peng Ma, Guo-Ya Gan
Journal of Marine Science and Technology
An emerging trend in performance evaluation is combining social network analysis methods with data envelopment analysis (DEA) models and using network centrality methods to distinguish DEA results. One study employed an input-oriented variable-returns-to-scale DEA model to address referent decision-making units and the corresponding lambda values to construct a network. This study referenced the literature and improved on the use of DEA weight sets to construct a network. We employed a context-dependent DEA model to delineate multiple effective frontier planes, aggregate the reference set relationships on each frontier plane to construct a network relationship matrix, and assess the influences of the …
Research On Improving The Salary Structure Of Port State Control Officers In Taiwan,
2023
North Taiwan Maritime Affairs Center, Maritime and Port Bureau, Ministry of Transportation and Communications, Keelung 200202, Taiwan
Research On Improving The Salary Structure Of Port State Control Officers In Taiwan, Te-Yi Chang, Wen-Chih Ho, Chung-Ping Liu, Yung-Wei Chen
Journal of Marine Science and Technology
The implementation of port state control (PSC) has been challenging in Taiwan due to the lack of port state control officers (PSCOs), and foreign ships berthing at ports in Taiwan that cannot be effectively inspected. PSCOs of Taiwan are subordinate to the public service system and restrained by the number of personnel by the Executive Yuan. Compared with similar professions, their salaries are significantly different from those of the industry, making recruiting and retaining PSCOs a difficult task. Accordingly, this study improved the salary structure of PSCOs by conducting field interviews with existing PSCOs in Taiwan and applying the Fuzzy-AHP …
Multi-Chamber Silencer Composed Of Screw-Perforated Tubes And Straight-Perforated Tubes,
2023
School of Intelligent Engineering, Shaoguan University, Guangdong, 512005, China
Multi-Chamber Silencer Composed Of Screw-Perforated Tubes And Straight-Perforated Tubes, Tian-Syung Lan, Min-Chie Chiu
Journal of Marine Science and Technology
The use of silencers to reduce noise is mandatory due to severe hearing damage caused by high venting noise in the engine room of ocean-going vessels. While straight and perforated tubes have been used as acoustical elements in traditional silencer design, studies have shown that the acoustical design still requires improvement. To enhance acoustical efficiency, the use of multi-chamber mufflers is proposed composed of screw and perforated tubes. Additionally, a mathematical finite element model built for acoustical simulation using the COMSOL program expedites the analysis of silencers with complicated acoustical elements. A sensitivity analysis of transmission loss concerning the geometric …
Numerical Analysis Of Silencer With A Coiled Tube And Straight Perforated Tube Using Fem,
2023
Department of Mechanicaland Materials Engineering, Tatung University, ROC.
Numerical Analysis Of Silencer With A Coiled Tube And Straight Perforated Tube Using Fem, Min-Chie Chiu, Ho-Chih Cheng
Journal of Marine Science and Technology
Marine diesel engine is essential on a ship, but emits extremely loud noise harmful to human hearing. Therefore, it is mandatory to use silencers to reduce the venting noise of the marine diesel engine. An advanced silencer with a new acoustical element of a curved tube, along with perforated holes, is presented to suppress the noise wave. To predict the silencer's acoustical performance for high-order waves, a finite element model was built using COMSOL. The influence of the silencer's noise reduction ability was investigated by exploring sensitivity using acoustical simulations on COMSOL, regarding the silencer's geometric factors. The results proved …
Methanol As An Eco-Environmental Alternative Fuel For Ships: A Case Study,
2023
Department of Naval Architecture and Marine Engineering, Faculty of Engineering, Alexandria University, Egypt
Methanol As An Eco-Environmental Alternative Fuel For Ships: A Case Study, Samar K. Sallam, Mohamed M. Elgohary, Ibrahim S. Seddiek
Journal of Marine Science and Technology
Global emissions of Green House Gases and air pollutants are significantly influenced by shipping. Diesel fuel use for energy production is primarily responsible for these emissions. The substitution of traditional marine diesel oil with methanol as a marine fuel is recommended in this study. Moreover, the methanol-diesel dual-fuel engine's environmental and financial benefits are investigated numerically. A cruise passenger ship named Costa Toscana has been evaluated as a case study. Based on the data, the suggested dual-fuel engine reduces emissions of CO2, NOx, SOx, and PM by 25.7%, 38.46%, 45%, and 45%, respectively, with a cost-effectiveness of 286.5, 6645, 268403.4, …
Path Planning Of Uav Navigation Mark Inspection Using A K-Means Clustering Aca,
2023
School of Navigation, Dalian Maritime University, Lingshui Road, Dalian, Liaoning 116031, China
Path Planning Of Uav Navigation Mark Inspection Using A K-Means Clustering Aca, Jiaqi Li, Weifeng Li, Wenting Zhang
Journal of Marine Science and Technology
With increasing speeds and application of artificial intelligence in the shipping industry, unmanned aerial vehicle (UAV) technology has been applied to navigation mark inspections to improve the inspection efficiency and safety. Aimed at the UAV path planning problem of navigation mark inspection, this paper proposes an improved K-means clustering ant colony algorithm (KCACA) to design the shortest route for UAV navigation mark inspections. First, the K-means algorithm and the UAV maximum flight distance were used to cluster the navigation marks, which were then split into several secondary clusters. Each cluster was regarded as an independent traveling salesman problem to be …
Collision Risk Prediction For Small Ships In South Korea Via Optimization Of Wireless Communication Period,
2023
Ocean Science and Technology School, Korea Maritime and Ocean University, Busan, South Korea, and Korea Institute of Ocean Science and Technology,, Busan, South Korea
Collision Risk Prediction For Small Ships In South Korea Via Optimization Of Wireless Communication Period, So-Ra Kim, Myoung-Ki Lee, Sangwon Park, Dae-Won Kim, Young-Soo Park
Journal of Marine Science and Technology
Since the emergence of COVID-19, there has been a global surge in demand for marine leisure activities. In Korea, the population using marine leisure has risen approximately 192% to 20,406 people, compared to 6,966 people in the year 2000, indicating a continuous growth over the past two decades.. Maritime transportation has become increasingly intricate worldwide due to the development of increasingly autonomous, larger, and faster ships. To effectively address potential hazards in such complex traffic environments, it is imperative to anticipate future scenarios and respond rapidly. However, small vessels account for the highest proportion of marine accidents, exhibit movements that …
Geohash-Based Arrangement Of Live-Fire Exercise Areas Using Ais,
2023
Future Ocean Information Technology, Jeju, Republic of Korea
Geohash-Based Arrangement Of Live-Fire Exercise Areas Using Ais, Sang-Lok Yoo, Cho-Young Jung
Journal of Marine Science and Technology
Live-fire exercise (LFX) areas at sea threaten the safety of ships, whereas, and indiscriminately abandoned unexploded bombs threaten the lives of fishermen. No statistical or scientific research has been conducted on the appropriate locations for LFX areas. Therefore, this study proposes a method for effectively arranging the LFX areas at sea that considers the safety of passing ships and national security. First, the proposed method classifies ship tracking data collected in the daytime based on the dawn and dusk times of the civil twilight phase. Second, the method uses a Geohash geocoding process to identify whether an LFX area coincides …
Bearing Capacity Factor Characteristics Of Footings On Double-Layered Cohesive Soils,
2023
Dept. of Civil Engineering, Feng Chia University, Taichung (407802), Taiwan
Bearing Capacity Factor Characteristics Of Footings On Double-Layered Cohesive Soils, Chao-Ming Chi, Zheng-Shan Lin, Yu-Shu Kuo
Journal of Marine Science and Technology
In this study, the bearing capacity of a surface foundation resting on a double-layered cohesive soil profile was investigated by applying a rotational mechanism and finite-difference numerical simulations. The bearing capacity factor behaviors of a surface footing on double-layered cohesive soils can be classified and illustrated using a characteristic chart. Depending on the soil strata strength ratio and normalized layer thickness, the soil-foundation system can be in the squeezing, factor-increasing, factor-decreasing, or constant factor zones. The results indicated that the trend of the curves in the characteristic chart computed from the asymmetric failure mechanism was in accordance with that of …
Research On Ice Resistance Of Ships Sailing In Floating Ice Floe,
2023
College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China
Research On Ice Resistance Of Ships Sailing In Floating Ice Floe, Zhixin Xiong, Xinyuan Wu, Yang Li
Journal of Marine Science and Technology
To study the ice resistance of ships in areas with floating ice, the Xuelong 2 icebreaker was simulated. A floating-ice model was established using the discrete-element method, and an ice particle array was generated using MATLAB. The effects of ice coverage and speed on ice drag were studied From the numerical simulation results, it can be seen that there is a certain trend in ice resistance under different ice coverage ranges, which changes with the change of speed.By comparing with the empirical formula and the numerical value of the ship model test, this numerical simulation results are relatively accurate.It also …
Research On Risk Assessment Of Container Operation Process In Ports Considering Functional Areas,
2023
Assistant professor, Department of Transportation and Logistics Management, National Yang Ming Chiao Tung University (Contact address: 8F, Assembly Building 1, No.1001, Daxue Rd., East Dist., Hsinchu City 30010, Taiwan
Research On Risk Assessment Of Container Operation Process In Ports Considering Functional Areas, Chen-Yu Lin, Ming-Jiu Hwang, Tzu-Heng Yen
Journal of Marine Science and Technology
The risk management of container ports has drawn significant attention recently in part because of recent high-profile accidents in global container ports and in part due to the increasing focus on port safety as a key element in sustainable maritime transportation. This research presented a novel, two-layer container port risk assessment model by partitioning the container port into four areas based on the process of container transportation: loading and unloading, in-port container transportation, storage, and gate areas. Failure mode and effects analysis (FMEA) and quantitative risk analysis modeling were combined for each part of the process to evaluate the risk …
Artificial Intelligence In Prediction Of The Remaining Useful Life Of Wind Turbine Shaft Bearings,
2023
Institute of Mechatronic Engineering
Artificial Intelligence In Prediction Of The Remaining Useful Life Of Wind Turbine Shaft Bearings, Jinsiang Shaw, B.J. Wu
Journal of Marine Science and Technology
Long-term periodic rotation and unstable load changes in wind turbines can cause unexpected damage to high-speed shaft bearings (HSSBs). In this study, after preprocessing of the HSSB vibration signal, four different models for predicting bearing degradation in terms of remaining useful life (RUL) in days were investigated: support vector regression (SVR), convolutional neural networks (CNN), long short-term memory (LSTM), and CNN-LSTM. The experimental results revealed that the CNN achieved the best mean absolute error (MAE), at 0.44 days, based on frequency response plot using the fast Fourier transform (FFT), while that of the CNN-LSTM model predicted using the amplitude profile …
Biotic And Abiotic Factors Associated With Temporal And Spatial Variability Of Constitutive Mixotroph Abundance And Proportion,
2023
College of William and Mary - Virginia Institute of Marine Science
Biotic And Abiotic Factors Associated With Temporal And Spatial Variability Of Constitutive Mixotroph Abundance And Proportion, Marcella Dobbertin Da Costa
Dissertations, Theses, and Masters Projects
Mixotrophic protists, which combine the use of photosynthesis and prey ingestion to obtain nutrients for growth, comprise a substantial portion of the plankton community. However, there is a major gap in our understanding of how mixotroph prevalence varies spatially and temporally and under what conditions they dominate. I utilized a recently developed molecular technique to experimentally identify active mixotrophs (taxa identified to be grazing when samples were collected) and combined this with microscopy data to estimate active mixotroph abundance and proportion at two locations in a temperate estuary over a year. Active mixotroph abundance was compared to potential mixotroph (taxa …
Subsurface Structure And Impacts Of Marine Heatwaves In The Chesapeake Bay,
2023
William & Mary - Virginia Institute of Marine Science
Subsurface Structure And Impacts Of Marine Heatwaves In The Chesapeake Bay, Nathan P. Shunk
Dissertations, Theses, and Masters Projects
Extreme temperature events known as Marine Heatwaves (MHW), akin to atmospheric heatwaves, have only recently received attention by the estuarine scientific community. Thus far, studies have focused solely on surface events due to scarcity of long-term subsurface data. This study investigates, for the first time, the subsurface temperature and dissolved oxygen (DO) anomalies associated with surface MHW events in a large, temperate, partially mixed estuary: the Chesapeake Bay (CB). Using over three decades (1986-2021) of in-situ data from several long-term monitoring programs in the CB (including sub daily moored measurements and monthly/bimonthly cruises along the main stem) and a global …
Effects Of Direct Water Injection On The Nitrogen Oxide Emission Characteristics Of Marine Diesel Engines,
2023
Department of Naval Architecture and Marine Engineering, Faculty of Engineering, Alexandria University, Alexandria 21544, Egypt
Effects Of Direct Water Injection On The Nitrogen Oxide Emission Characteristics Of Marine Diesel Engines, Mahmoud Abdelnaser Saadeldin, M. M. Elgoharya, Maged Abdelnaby, Mohamed R. Shouman
Journal of Marine Science and Technology
This study examines the issue of diesel emissions from vehicles and vessels and their impact on environmental degradation with a focus on nitrogen oxide (NOx) emissions and their contribution to air pollution-related deaths worldwide. The novelty of this work is the use of computational fluid dynamics simulations to investigate the effectiveness of water addition for reducing NOx emissions. This study considers two methods of water addition, i.e., injection of water and air into a combustion chamber and mixing of water with fuel before injection. Adding water to air systems at 10% and 20% ratios reduces NOx emissions by 5% and …
Rapid Species Identification Of Meretrix Lusoria And Three Other Meretrix Clams Using Pcr And Rflp Analysis Of The Mitochondrial Coii Gene.,
2023
Department of Aquaculture, National Taiwan Ocean University, Keelung, Taiwan b
Rapid Species Identification Of Meretrix Lusoria And Three Other Meretrix Clams Using Pcr And Rflp Analysis Of The Mitochondrial Coii Gene., Chia-Hsuan Sung, Liang-Jong Wang, Chang-Wen Huang
Journal of Marine Science and Technology
Meretrix clams are among the most economically important species of bivalves in Eastern Asia and Taiwan. In the past, the identification of these hard clams depended on the shell morphology; however, species identification based on shell markings and shapes confuses the taxonomy of the Meretrix genus. The DNA molecular information is useful and can easily identify them accurately and quickly, especially the sequence of mitochondrial DNA. In this study, a PCR method to analyze the mitochondrial cytochrome c oxidase II (COII) gene was developed to rapidly identify of M. lusoria, M. lamarckii, M. lyrata and M. petechialis. Four different species …
A Methodology For Statistical Mean Wave Climate Regime Characterisation In Oceanic Islands: The Case Of The Southern Coast Of Tenerife,
2023
School of Doctoral and Postgraduate Programs, University of La Laguna, La Laguna, S/C Tenerife, Canary Island, 38200, Spain.
A Methodology For Statistical Mean Wave Climate Regime Characterisation In Oceanic Islands: The Case Of The Southern Coast Of Tenerife, Emilio Megías, Manuel García-Román
Journal of Marine Science and Technology
Oceanic islands of volcanic origin tend to have peculiar characteristics, such as: exposure to many wave directions; grouping in archipelagos; steep coastal slopes; and small coastal shelves. All these features require certain considerations in wave climate studies. These types of studies, when wave spectra are not available and have to be performed with parametric data, can be unreliable without an adequate systematic treatment. In this work we propose a methodology consisting of pre-classification according to the peak period and subsequent separation into different sectors according to the geographical fetch. The island of Tenerife is the case study, and in particular …
Inventory Management In Supply Chains With Consideration Of Transportation And Green Technology Cost Under Progressive Carbon Taxation,
2023
Department of Transportation Science, National Taiwan Ocean University, Taiwan, ROC
Inventory Management In Supply Chains With Consideration Of Transportation And Green Technology Cost Under Progressive Carbon Taxation, Ming-Feng Yang, Min-Der Ko, Hung-Jen Tu, Mengru Tu, Jun-Yuan Kuo, Yen-Ting Chao, Shang-Wei Shih
Journal of Marine Science and Technology
Reducing carbon emissions is an important issue in the global supply chain. Governments have formulated different carbon policies to achieve carbon neutrality or emission reduction, in particular, the carbon tax as a policy provides greater certainty about the potential cost to emitters. The Taiwan government is expected to implement the carbon tax policy in 2024 and does not rule out the inclusion of a progressive mechanism which is more effective than a single carbon tax in curbing high carbon emissions Recent studies have also confirmed that a high level and complete carbon tax could encourage companies to invest in green …
Genetic Algorithm For Solving A Just-In-Time Inventory Model With Imperfect Rework Implemented In A Serial Multi-Echelon System,
2023
Department of Shipping and Transportation Management, National Taiwan Ocean University, Taiwan
Genetic Algorithm For Solving A Just-In-Time Inventory Model With Imperfect Rework Implemented In A Serial Multi-Echelon System, Hsien-Chung Tsao, Cheng-Chi Chung, Hsuan-Shih Lee, Chih-Ping Lin, Yan-Yun Tu, Ssu-Chi Lin
Journal of Marine Science and Technology
As global industrial competition intensifies, enterprises can achieve substantial competitive advantages in the supply chain management environment by promptly meeting customer demands and efficiently reducing both supply and demand costs. This paper proposes an inventory model for supply chain optimization that considers uncertain delivery lead times and defective products. Solving the model requires solving a nonlinear mixed-integer problem, which traditionally requires considerable time. Solutions to nondeterministic polynomial-time hard problems with high complexity and difficulty are often obtained using heuristic algorithms. Among these algorithms, genetic algorithms have high efficiency and quality. Therefore, we employed a genetic algorithm to solve the proposed …
Assessing Hierarchical Corporate Sustainability Transition Practices Under Uncertainty: An Approach In The Port And Shipping Industry In Southeast Asia,
2023
Department of Shipping and Transportation Management, National Taiwan Ocean University, Taiwan
Assessing Hierarchical Corporate Sustainability Transition Practices Under Uncertainty: An Approach In The Port And Shipping Industry In Southeast Asia, Mei-Train Yeh, Feng-Ming Tsai, Taufik Kurrahman
Journal of Marine Science and Technology
The port and shipping industry in Southeast Asia has experienced significant development in response to the increasing demand for maritime logistics and transportation services. However, this expansion has resulted in notable social and environmental impacts. Consequently, it is imperative for both scholars and practitioners to comprehend the concept of corporate sustainability transition (CST), which entails the establishment of shipping operations that effectively balance environmental, social, and economic considerations. Additionally, technologies that are used to facilitate the transition process must be investigated. Several studies have been undertaken to ascertain the attributes pertaining to sustainability transition. Nevertheless, there has been a lack …
