Pub Date : 2024-01-22DOI: 10.5750/ijme.v165ia3.1248
Bertrand Malas, Luke Creasey, Dickon Buckland, S. Turnock
The process of design, build and eventual commissioning of the towing tank on the Boldrewood Innovation Campus is described. The design brief required a facility that would have a capability to test models at a commercial scale but that would be effective as teaching environment for the next generation of Naval Architects as well as providing a flexible space for future fundamental research. Each of these provided their own challenges but the eventual solution of a 138 m long, 3.5 m deep, 6 m wide facility has more than met the initial aspirations. Equipped with 12 independent 0.5 m wavemaking flaps at the West end, a passive beach at the East end, a deployable side beach along the South wall for post run wave absorption and a monocoque Aluminium alloy carriage, the Boldrewood towing tank has now been successfully operating for more than a year. The carriage position and speed are controlled by a twin winch arrangement using a laser positioning system and low embodied energy composite cables. The carriage can reach a maximum speed of 10 m/s with controllable acceleration rates and can have up to four constant speed phases per run. Initial commissioning results and comparisons with benchmark data for the KCS hull confirm the accuracy and repeatability of the facility. In particular, the position and speed of the carriage are known to a high level of precision. To date research and consultancy work has spanned the performance of high speed vessels, uncrewed underwater and surface vessels, wave energy and tidal current systems, floating platforms for wind turbines, performance sport work for sailing, kayaking, rowing and swimming, open water propeller tests as well as conventional displacement vessel testing for self-propulsion and resistance. All ship science and maritime engineering students use the facility as part of their taught modules in every year of their programme as well as for individual, MSc and group projects as appropriate. It has also made a strong impact on the many thousands of visitors a year to the campus for science and engineering open days.
{"title":"Design, Development and Commissioning of the Boldrewood Towing Tank – A Decade of Endeavour","authors":"Bertrand Malas, Luke Creasey, Dickon Buckland, S. Turnock","doi":"10.5750/ijme.v165ia3.1248","DOIUrl":"https://doi.org/10.5750/ijme.v165ia3.1248","url":null,"abstract":"The process of design, build and eventual commissioning of the towing tank on the Boldrewood Innovation Campus is described. The design brief required a facility that would have a capability to test models at a commercial scale but that would be effective as teaching environment for the next generation of Naval Architects as well as providing a flexible space for future fundamental research. Each of these provided their own challenges but the eventual solution of a 138 m long, 3.5 m deep, 6 m wide facility has more than met the initial aspirations. Equipped with 12 independent 0.5 m wavemaking flaps at the West end, a passive beach at the East end, a deployable side beach along the South wall for post run wave absorption and a monocoque Aluminium alloy carriage, the Boldrewood towing tank has now been successfully operating for more than a year. The carriage position and speed are controlled by a twin winch arrangement using a laser positioning system and low embodied energy composite cables. The carriage can reach a maximum speed of 10 m/s with controllable acceleration rates and can have up to four constant speed phases per run. Initial commissioning results and comparisons with benchmark data for the KCS hull confirm the accuracy and repeatability of the facility. In particular, the position and speed of the carriage are known to a high level of precision. To date research and consultancy work has spanned the performance of high speed vessels, uncrewed underwater and surface vessels, wave energy and tidal current systems, floating platforms for wind turbines, performance sport work for sailing, kayaking, rowing and swimming, open water propeller tests as well as conventional displacement vessel testing for self-propulsion and resistance. All ship science and maritime engineering students use the facility as part of their taught modules in every year of their programme as well as for individual, MSc and group projects as appropriate. It has also made a strong impact on the many thousands of visitors a year to the campus for science and engineering open days.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140500608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.5750/ijme.v165ia3.1194
Yu-Chang Hsu, Hua-An Lu, Ching-Wu Chu
Ship repair service providers (SRSPs) are divided into repair shops and repair yards. The process of evaluating the service quality of SRSPs is detailed in the ship management and operation procedures held by ship-owners, who must evaluate SRSPs annually to ensure the continued provision of high-quality maintenance and repair services. The high-quality repair services provided by SRSPs can also enhance the strength of ship-owners; ensure the ship successfully passes Flag, PSC, and CLASS inspections; and maintain the ship’s seaworthiness. This study combined fuzzy quality function deployment (FQFD) and grey relational analysis (GRA) to evaluate the service quality of SRSPs. The research findings revealed that “reasonable pricing and discount conditions” and “high-quality repairs and reliability-centred guarantee service” are the technical solutions that must be prioritised by repair shops and yards, respectively. Moreover, the evaluation criteria, technical solutions, and research results discussed in this study provide a reference for ship-owners and SRSPs.
船舶维修服务提供商（SRSP）分为修理厂和修理厂。船东持有的船舶管理和营运程序中详细规定了对修船服务提供商服务质量的评估过程，船东必须每年对修船服务提供商进行评估，以确保持续提供高质量的维护和修理服务。自律维修商提供的高质量维修服务还能增强船东的实力，确保船舶顺利通过船旗、PSC 和 CLASS 检验，保持船舶的适航性。本研究结合模糊质量功能展开（FQFD）和灰色关系分析（GRA）对自修船厂的服务质量进行了评估。研究结果表明，"合理定价和折扣条件 "和 "高质量维修和以可靠性为中心的保障服务 "分别是修理厂和船厂必须优先考虑的技术解决方案。此外，本研究讨论的评价标准、技术解决方案和研究成果也为船东和 SRSP 提供了参考。
{"title":"The Technology Solutions of Service Quality for Ship Repair Service Providers","authors":"Yu-Chang Hsu, Hua-An Lu, Ching-Wu Chu","doi":"10.5750/ijme.v165ia3.1194","DOIUrl":"https://doi.org/10.5750/ijme.v165ia3.1194","url":null,"abstract":"Ship repair service providers (SRSPs) are divided into repair shops and repair yards. The process of evaluating the service quality of SRSPs is detailed in the ship management and operation procedures held by ship-owners, who must evaluate SRSPs annually to ensure the continued provision of high-quality maintenance and repair services. The high-quality repair services provided by SRSPs can also enhance the strength of ship-owners; ensure the ship successfully passes Flag, PSC, and CLASS inspections; and maintain the ship’s seaworthiness. This study combined fuzzy quality function deployment (FQFD) and grey relational analysis (GRA) to evaluate the service quality of SRSPs. The research findings revealed that “reasonable pricing and discount conditions” and “high-quality repairs and reliability-centred guarantee service” are the technical solutions that must be prioritised by repair shops and yards, respectively. Moreover, the evaluation criteria, technical solutions, and research results discussed in this study provide a reference for ship-owners and SRSPs.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140500433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.5750/ijme.v165ia3.1212
Bingchun Liu, Xingyu Wang, Shiming Zhao, Yan Xu
The Baltic dry index (BDI) is not only one of the most important indicators of shipping costs but is also an important barometer of global trade and manufacturing sentiment. The BDI is highly volatile and subject to complex factors, which make it difficult to predict. In this paper, a neural network model-based BDI forecasting system was proposed to effectively forecast the BDI. We used the gray relational degree analysis method to select seven factors with higher correlation from 15 factors affecting the variation of BDI index to be used as input indicators for the bi-directional long short-term memory (BiLSTM) model to forecast BDI. From the experimental results, the prediction model proposed in this paper had an excellent prediction effect on the BDI. The mape value of the prediction result was 9.19%. The accuracy was better than the common machine learning models SVR and REG and the neural network model LSTM. In addition, in order to further optimize the prediction performance of the combined model GRA-BiLSTM, this paper introduced the MIV method to conduct an in-depth analysis of the contribution of each variable to the prediction results. Rice price, Shanghai securities composite index and crude oil price were found to be the three most relevant indicators to the prediction accuracy of the model.
{"title":"Prediction of Baltic Dry Index Based on GRA-BiLSTM Combined Model","authors":"Bingchun Liu, Xingyu Wang, Shiming Zhao, Yan Xu","doi":"10.5750/ijme.v165ia3.1212","DOIUrl":"https://doi.org/10.5750/ijme.v165ia3.1212","url":null,"abstract":"The Baltic dry index (BDI) is not only one of the most important indicators of shipping costs but is also an important barometer of global trade and manufacturing sentiment. The BDI is highly volatile and subject to complex factors, which make it difficult to predict. In this paper, a neural network model-based BDI forecasting system was proposed to effectively forecast the BDI. We used the gray relational degree analysis method to select seven factors with higher correlation from 15 factors affecting the variation of BDI index to be used as input indicators for the bi-directional long short-term memory (BiLSTM) model to forecast BDI. From the experimental results, the prediction model proposed in this paper had an excellent prediction effect on the BDI. The mape value of the prediction result was 9.19%. The accuracy was better than the common machine learning models SVR and REG and the neural network model LSTM. In addition, in order to further optimize the prediction performance of the combined model GRA-BiLSTM, this paper introduced the MIV method to conduct an in-depth analysis of the contribution of each variable to the prediction results. Rice price, Shanghai securities composite index and crude oil price were found to be the three most relevant indicators to the prediction accuracy of the model.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140500306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.5750/ijme.v165ia3.1230
C. Kartoğlu, Yunus Emre Senol, S. Kum
High speed craft has become prominent in maritime industry. Sophisticated electronic navigation equipment on bridge increases mental demands of high speed craft navigator. In the present study, mental workload of high speed craft navigators has been assessed in terms of bridge navigation operations. For this purpose, the pairwise comparison of the effects of Electronic Chart Display and Information System, Automatic Radar Plotting Aid, Automatic Identification System and autopilot on mental workload and Revised NASA Task Load Index questionnaires were carried out. High speed craft navigators sorted berthing, unberthing, navigation in coastal waters, navigation in restricted waters, and navigation on open sea operations according to their mental workload levels. In addition, they indicated the factors mostly affecting mental workload and the remarkable suggestions to keep the optimum level of mental workload. As result of these findings, considerations have been made for increasing the safety of high speed craft navigation.
高速船在航海业中的地位日益突出。舰桥上先进的电子导航设备增加了高速船领航员的脑力需求。本研究从驾驶台导航操作的角度对高速船领航员的脑力劳动负荷进行了评估。为此，对电子海图显示和信息系统、自动雷达绘图辅助系统、自动识别系统和自动驾驶仪对脑力劳动负荷的影响进行了配对比较，并编制了修订版 NASA 任务负荷指数问卷。高速船领航员根据其脑力劳动负荷水平对靠泊、离泊、沿海水域航行、限制水域航行和公海航行进行了分类。此外，他们还指出了影响脑力劳动负荷的主要因素以及保持最佳脑力劳动负荷水平的重要建议。这些研究结果为提高高速船航行的安全性提供了参考。
{"title":"Assessment of Seafarers’ Mental Workload: A Study on High Speed Craft","authors":"C. Kartoğlu, Yunus Emre Senol, S. Kum","doi":"10.5750/ijme.v165ia3.1230","DOIUrl":"https://doi.org/10.5750/ijme.v165ia3.1230","url":null,"abstract":"High speed craft has become prominent in maritime industry. Sophisticated electronic navigation equipment on bridge increases mental demands of high speed craft navigator. In the present study, mental workload of high speed craft navigators has been assessed in terms of bridge navigation operations. For this purpose, the pairwise comparison of the effects of Electronic Chart Display and Information System, Automatic Radar Plotting Aid, Automatic Identification System and autopilot on mental workload and Revised NASA Task Load Index questionnaires were carried out. High speed craft navigators sorted berthing, unberthing, navigation in coastal waters, navigation in restricted waters, and navigation on open sea operations according to their mental workload levels. In addition, they indicated the factors mostly affecting mental workload and the remarkable suggestions to keep the optimum level of mental workload. As result of these findings, considerations have been made for increasing the safety of high speed craft navigation.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140499323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-10DOI: 10.5750/ijme.v165ia1.1172
Burcu Çelik, Y. Zorba
This paper aims to analyse maritime traffic safety assessment via a traffic flow simulation model. The model developed via NetLogo platform, agent-based modelling and simulation approach. And it is implemented on an open sea area, at the Aegean Sea to show its applicability. The model is verified through experiments conducted in the area. The simulation outputs give the risky locations and scores. Risky locations and risk scores in the area are determined as the outputs of the simulation runs. A traffic separation scheme is established to prove the suitability of the model as adaptable and updatable. After the scheme is implemented, it shows that the potential collision locations and scores change considerably. The developed model is convenient to simulate various conditions by changing the input parameters on maritime traffic safety
{"title":"AN APPLICATION OF AGENT-BASED TRAFFIC FLOW MODEL FOR MARITIME SAFETY MANAGEMENT EVALUATION","authors":"Burcu Çelik, Y. Zorba","doi":"10.5750/ijme.v165ia1.1172","DOIUrl":"https://doi.org/10.5750/ijme.v165ia1.1172","url":null,"abstract":"This paper aims to analyse maritime traffic safety assessment via a traffic flow simulation model. The model developed via NetLogo platform, agent-based modelling and simulation approach. And it is implemented on an open sea area, at the Aegean Sea to show its applicability. The model is verified through experiments conducted in the area. The simulation outputs give the risky locations and scores. Risky locations and risk scores in the area are determined as the outputs of the simulation runs. A traffic separation scheme is established to prove the suitability of the model as adaptable and updatable. After the scheme is implemented, it shows that the potential collision locations and scores change considerably. The developed model is convenient to simulate various conditions by changing the input parameters on maritime traffic safety","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46499653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-10DOI: 10.5750/ijme.v165ia1.791
B. Shabani
Wave load cycles, wet-deck slamming events, accelerations and motion comfort are important considerations for high-speed catamarans operating in moderate to large waves. Although developing a hull monitoring system according to classification guidelines for such vessels is broadly acceptable, the data processing requirements for outputs such as rainflow counting, filtering, probability distribution, fatigue damage estimation and warning due to slamming can be as sophisticated to implement as the system components themselves. Advanced analytics such as machine learning and deep learning data pipelines will also create more complexities for such systems, if included. This paper provides an overview of data analytics methods and cloud computing resources for remotely monitoring motions and structural responses of a 111 m high-speed catamaran. To satisfy the data processing requirements, MATLAB Reference Architectures on Amazon Web Services (AWS) were used. Such combination enabled fast parallel computing and advanced feature engineering in a time-efficient manner. A MATLAB Production Server on AWS has been set up for near real-time analytics and execution of functions developed according to the class guidelines. A case study using Long Short‑Term Memory (LSTM) networks for ship speed and Motion Sickness Incidence (MSI) is provided and discussed. Such data architecture provides a flexible and scalable solution, leading to deeper insights through big data processing and machine learning, which supports hull monitoring functions as a service.
波浪载荷周期、湿甲板撞击事件、加速度和运动舒适性是高速双体船在中大浪中运行的重要考虑因素。尽管根据此类船舶的分类指南开发船体监测系统被广泛接受，但输出的数据处理要求，如雨流计数、过滤、概率分布、疲劳损伤估计和撞击警告，可能与系统组件本身一样复杂，难以实现。机器学习和深度学习数据管道等高级分析也将为此类系统带来更多复杂性。本文概述了用于远程监测111米高速双体船运动和结构响应的数据分析方法和云计算资源。为了满足数据处理需求，使用了Amazon Web Services (AWS)上的MATLAB参考体系结构。这样的组合使快速并行计算和先进的特征工程在时间效率的方式。在AWS上建立了MATLAB生产服务器，用于根据类指南开发的近实时分析和执行功能。提供并讨论了使用长短期记忆(LSTM)网络进行船舶速度和晕动病发生率(MSI)的案例研究。这种数据架构提供了一种灵活且可扩展的解决方案，通过大数据处理和机器学习提供更深入的见解，从而支持船体监测功能即服务。
{"title":"INTELLIGENT MONITORING OF A LARGE CATAMARAN FERRY","authors":"B. Shabani","doi":"10.5750/ijme.v165ia1.791","DOIUrl":"https://doi.org/10.5750/ijme.v165ia1.791","url":null,"abstract":"Wave load cycles, wet-deck slamming events, accelerations and motion comfort are important considerations for high-speed catamarans operating in moderate to large waves. Although developing a hull monitoring system according to classification guidelines for such vessels is broadly acceptable, the data processing requirements for outputs such as rainflow counting, filtering, probability distribution, fatigue damage estimation and warning due to slamming can be as sophisticated to implement as the system components themselves. Advanced analytics such as machine learning and deep learning data pipelines will also create more complexities for such systems, if included. This paper provides an overview of data analytics methods and cloud computing resources for remotely monitoring motions and structural responses of a 111 m high-speed catamaran. To satisfy the data processing requirements, MATLAB Reference Architectures on Amazon Web Services (AWS) were used. Such combination enabled fast parallel computing and advanced feature engineering in a time-efficient manner. A MATLAB Production Server on AWS has been set up for near real-time analytics and execution of functions developed according to the class guidelines. A case study using Long Short‑Term Memory (LSTM) networks for ship speed and Motion Sickness Incidence (MSI) is provided and discussed. Such data architecture provides a flexible and scalable solution, leading to deeper insights through big data processing and machine learning, which supports hull monitoring functions as a service.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47261201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-10DOI: 10.5750/ijme.v165ia1.1177
U. Yıldırım, Gani Mustafa İnegol
Sustainability and safety in the maritime sector mostly relies on seafarers for ensure the safe and secure operation of ships. Selection of personnel in the maritime sector is based on a large number of criteria, and is dictated by the seafarer’s qualification and the type of ship. The present study identifies 24 criteria in the form of personal, professional, physical, and technical competencies, categorized under four main headings, and calculates the weights of these criteria in terms of their importance. It goes on to present the general seafarer criteria and the different criteria required by different types of companies, and finally presents a model that can serve as a guide the in the selection of the best seafarer depending on the ship type. The study makes use of Step-Wise Weight Assessment Ratio Analysis and Additive Ratio Assessment methods, which are multi-criteria decision making methods.
{"title":"SEAFARER SELECTION FOR SUSTAINABLE SHIPPING: CASE STUDY FOR TURKEY","authors":"U. Yıldırım, Gani Mustafa İnegol","doi":"10.5750/ijme.v165ia1.1177","DOIUrl":"https://doi.org/10.5750/ijme.v165ia1.1177","url":null,"abstract":"Sustainability and safety in the maritime sector mostly relies on seafarers for ensure the safe and secure operation of ships. Selection of personnel in the maritime sector is based on a large number of criteria, and is dictated by the seafarer’s qualification and the type of ship. The present study identifies 24 criteria in the form of personal, professional, physical, and technical competencies, categorized under four main headings, and calculates the weights of these criteria in terms of their importance. It goes on to present the general seafarer criteria and the different criteria required by different types of companies, and finally presents a model that can serve as a guide the in the selection of the best seafarer depending on the ship type. The study makes use of Step-Wise Weight Assessment Ratio Analysis and Additive Ratio Assessment methods, which are multi-criteria decision making methods.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41400349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-10DOI: 10.5750/ijme.v165ia1.1200
Tarik Taspinar, Zeynep Orman
Decreasing the fuel consumption and thus greenhouse gas emissions of vessels have emerged as a critical topic for both ship operators and policymakers in recent years. The speed of vessels has long been recognized to have the highest impact on fuel consumption. The aim of this study is to develop a speed optimization model using a time-constrained genetic algorithm (GA). Subsequent to this, this paper also presents the application of machine learning regression methods in constructing a model to predict the fuel consumption of vessels. The local outlier factor algorithm is used to eliminate outliers in prediction features. The overfitting problem is observed after hyperparameter tuning in boosting and tree-based regression prediction methods. The early stopping technique is applied for overfitted models. In this study, speed is found to be the most significant feature for fuel consumption prediction. On the other hand, GA evaluation results showed that random modifications in the default speed profile could increase GA performance and thus fuel savings more than constant speed limits during voyages.
{"title":"VOYAGE SPEED OPTIMIZATION USING GENETIC ALGORITHM","authors":"Tarik Taspinar, Zeynep Orman","doi":"10.5750/ijme.v165ia1.1200","DOIUrl":"https://doi.org/10.5750/ijme.v165ia1.1200","url":null,"abstract":"Decreasing the fuel consumption and thus greenhouse gas emissions of vessels have emerged as a critical topic for both ship operators and policymakers in recent years. The speed of vessels has long been recognized to have the highest impact on fuel consumption. The aim of this study is to develop a speed optimization model using a time-constrained genetic algorithm (GA). Subsequent to this, this paper also presents the application of machine learning regression methods in constructing a model to predict the fuel consumption of vessels. The local outlier factor algorithm is used to eliminate outliers in prediction features. The overfitting problem is observed after hyperparameter tuning in boosting and tree-based regression prediction methods. The early stopping technique is applied for overfitted models. In this study, speed is found to be the most significant feature for fuel consumption prediction. On the other hand, GA evaluation results showed that random modifications in the default speed profile could increase GA performance and thus fuel savings more than constant speed limits during voyages.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45464318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-10DOI: 10.5750/ijme.v165ia1.1208
G. An, Jeongung Park, Dae-Jeong Seong, I. Han
High-manganese austenitic steel has been developed as a new cryogenic steel for application in liquified natural gas (LNG) storage and fuel tanks, with improved fracture toughness and safety at cryogenic temperatures. Generally, the fracture toughness decreases at lower temperatures; therefore, cryogenic steel requires a high fracture toughness to prevent unstable fractures. This study conducted unstable ductile fracture tests with 30-mm-thick high-manganese austenitic steel and evaluated its applicability to LNG storage and fuel tanks. The ductile fracture resistance in the weld joints was evaluated, including the weld metal and heat-affected zone. The unstable fracture resistance was evaluated for different LNG tank types. It was found that high-manganese austenitic steel has excellent unstable fracture characteristics and good material performance as a cryogenic steel; therefore, it can be applied in LNG storage and fuel tanks.
{"title":"FRACTURE SAFETY OF LIQUEFIED NATURAL GAS TANK IN CRYOGENIC CONDITIONS","authors":"G. An, Jeongung Park, Dae-Jeong Seong, I. Han","doi":"10.5750/ijme.v165ia1.1208","DOIUrl":"https://doi.org/10.5750/ijme.v165ia1.1208","url":null,"abstract":"High-manganese austenitic steel has been developed as a new cryogenic steel for application in liquified natural gas (LNG) storage and fuel tanks, with improved fracture toughness and safety at cryogenic temperatures. Generally, the fracture toughness decreases at lower temperatures; therefore, cryogenic steel requires a high fracture toughness to prevent unstable fractures. This study conducted unstable ductile fracture tests with 30-mm-thick high-manganese austenitic steel and evaluated its applicability to LNG storage and fuel tanks. The ductile fracture resistance in the weld joints was evaluated, including the weld metal and heat-affected zone. The unstable fracture resistance was evaluated for different LNG tank types. It was found that high-manganese austenitic steel has excellent unstable fracture characteristics and good material performance as a cryogenic steel; therefore, it can be applied in LNG storage and fuel tanks.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46773222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-10DOI: 10.5750/ijme.v165ia1.1203
B. K. Tiwari, D. R. Sharma, Tae-Wan Kim
Autonomous Underwater Vehicles (AUVs) are used for the underwater survey both in coastal areas and deep sea without any human intervention during their operations. However, high energy consumptions required by the thrusters of the AUV’s adversely affect their performance such as range and endurance, etc. Herein, we have presented a novel design and development of a standalone variable buoyancy system for autonomous underwater vehicle and investigated the numerical and experimental analysis of Variable Buoyancy System (VBS) in standalone mode. Design idea is based upon the ‘Pump Driven Variable Buoyancy System (PDVBS)’ using ‘Water Hydraulic Variable Buoyancy System (WHVBS)’ method to control the buoyancy using a diaphragm type positive displacement pump (PDP) with capacity of the maximum buoyancy change rate of 4.5 kg/min. Detail experimental and simulation performance of the developed VBS has been investigated. Developed VBS is tested for maximum depth of 5 m and compared the performance of the experimental and simulation results. Presented results demonstrate that designed VBS is effective in changing buoyancy and controlling heave velocities and that will result to achieve the higher range and endurance and better performance in rescue/attack operations.
{"title":"EXPERIMENTAL STUDY OF A VARIABLE BUOYANCY SYSTEM FOR LOW DEPTH OPERATION","authors":"B. K. Tiwari, D. R. Sharma, Tae-Wan Kim","doi":"10.5750/ijme.v165ia1.1203","DOIUrl":"https://doi.org/10.5750/ijme.v165ia1.1203","url":null,"abstract":"Autonomous Underwater Vehicles (AUVs) are used for the underwater survey both in coastal areas and deep sea without any human intervention during their operations. However, high energy consumptions required by the thrusters of the AUV’s adversely affect their performance such as range and endurance, etc. Herein, we have presented a novel design and development of a standalone variable buoyancy system for autonomous underwater vehicle and investigated the numerical and experimental analysis of Variable Buoyancy System (VBS) in standalone mode. Design idea is based upon the ‘Pump Driven Variable Buoyancy System (PDVBS)’ using ‘Water Hydraulic Variable Buoyancy System (WHVBS)’ method to control the buoyancy using a diaphragm type positive displacement pump (PDP) with capacity of the maximum buoyancy change rate of 4.5 kg/min. Detail experimental and simulation performance of the developed VBS has been investigated. Developed VBS is tested for maximum depth of 5 m and compared the performance of the experimental and simulation results. Presented results demonstrate that designed VBS is effective in changing buoyancy and controlling heave velocities and that will result to achieve the higher range and endurance and better performance in rescue/attack operations.","PeriodicalId":50313,"journal":{"name":"International Journal of Maritime Engineering","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45974969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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