The ever-increasing consumption of electrical energy due to increasing requirements arising in parallel with the developing technology forces manufactures and users to seek new and environmentally compatible energy resources. Due to it endless energy potential and continuity, wind energy, which has been used by humanity for various purposes for centuries, continues its journey, which started with windmills that transform one form of mechanical energy into another, with offshore wind energy turbines. In this study, installation site selection, which is the first step for floating offshore wind turbine installation, is carried out. First, a Fuzzy Analytic Hierarchy Process (F-AHP) is applied to obtain the weights of criteria. Transformed alternatives and criteria in a fuzzy decision matrix through triangular fuzzy numbers are used to obtain a database via a Geographic Information System (GIS). Finally, the installation site and study area are determined. This area is located in the Northeast Aegean Sea, between Çanakkale and Gökçeada, 12 km to the northeast of Gökçeada, and 12 square kilometers. The minimum distance of the area to ship routes is 3000 m, and its minimum distance to fault lines is 2000 m. The average sea depth is 110 m, and the average wind speed is 9.26 m/s (18 knots). With this potential, enough energy can be generated for settlements on Gökçeada and the coastlines.
{"title":"GIS-based floating offshore wind turbine installation site selection using fuzzy analytic hierarchy process in northeast Aegean Sea","authors":"S. A. Erkurtulmus, Emre Pesman","doi":"10.21278/brod75204","DOIUrl":"https://doi.org/10.21278/brod75204","url":null,"abstract":"The ever-increasing consumption of electrical energy due to increasing requirements arising in parallel with the developing technology forces manufactures and users to seek new and environmentally compatible energy resources. Due to it endless energy potential and continuity, wind energy, which has been used by humanity for various purposes for centuries, continues its journey, which started with windmills that transform one form of mechanical energy into another, with offshore wind energy turbines. In this study, installation site selection, which is the first step for floating offshore wind turbine installation, is carried out. First, a Fuzzy Analytic Hierarchy Process (F-AHP) is applied to obtain the weights of criteria. Transformed alternatives and criteria in a fuzzy decision matrix through triangular fuzzy numbers are used to obtain a database via a Geographic Information System (GIS). Finally, the installation site and study area are determined. This area is located in the Northeast Aegean Sea, between Çanakkale and Gökçeada, 12 km to the northeast of Gökçeada, and 12 square kilometers. The minimum distance of the area to ship routes is 3000 m, and its minimum distance to fault lines is 2000 m. The average sea depth is 110 m, and the average wind speed is 9.26 m/s (18 knots). With this potential, enough energy can be generated for settlements on Gökçeada and the coastlines.","PeriodicalId":55594,"journal":{"name":"Brodogradnja","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140354864","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}
Taking the maximum contact pressure as the objective function for, the optimal design model of the offshore flange connector was established to analyze the impact of the flange cone's angle and the curvature radius of the lenticular gasket's contact surface on the sealing performance of the connector. An optimized three-dimensional model of the offshore flange connector was constructed using the MATLAB software's fmincon function to obtain the optimal size of the cone angle and curvature radius. The maximum contact pressure and maximum equivalent stress values of the non-optimized and optimized offshore flange connectors under the cross combination of two design pressures and six operating temperatures were analyzed by Workbench software, and the sealing performance of the non-optimized and optimized offshore flange connectors was compared according to the sealing judgment basis. The results show that compared with the previously studied offshore flange connector, the sealing structure of optimized offshore flange exhibits maximum increase in contact pressure increase but maximum decrease in equivalent stress. Under actual operating circumstances, the optimized offshore flange connection performs better in sealing and is less prone to breakage.
{"title":"Research on optimal design of 6in offshore flange connector’s sealing structure","authors":"Jianguo Qin, Minghui Ji, Haixia Gong, Sijia Guo, Yanfeng Zhang, Yejiang Li, Haitang Cen","doi":"10.21278/brod75207","DOIUrl":"https://doi.org/10.21278/brod75207","url":null,"abstract":"Taking the maximum contact pressure as the objective function for, the optimal design model of the offshore flange connector was established to analyze the impact of the flange cone's angle and the curvature radius of the lenticular gasket's contact surface on the sealing performance of the connector. An optimized three-dimensional model of the offshore flange connector was constructed using the MATLAB software's fmincon function to obtain the optimal size of the cone angle and curvature radius. The maximum contact pressure and maximum equivalent stress values of the non-optimized and optimized offshore flange connectors under the cross combination of two design pressures and six operating temperatures were analyzed by Workbench software, and the sealing performance of the non-optimized and optimized offshore flange connectors was compared according to the sealing judgment basis. The results show that compared with the previously studied offshore flange connector, the sealing structure of optimized offshore flange exhibits maximum increase in contact pressure increase but maximum decrease in equivalent stress. Under actual operating circumstances, the optimized offshore flange connection performs better in sealing and is less prone to breakage.","PeriodicalId":55594,"journal":{"name":"Brodogradnja","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140771775","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}
Subsea jumpers play a critical role in subsea oil and gas production. Structural damage such as cracks is inevitable in subsea jumpers due to the harsh marine environment (internal fluid flow corrosion, high temperature and pressure, etc.). However, the current research on damage detection and evaluation of subsea jumpers is limited, particularly in cases of slight damage. This study thus proposes a method to identify cracks in subsea jumpers based on the modal characteristics and fractal theory. The accuracy of the method is verified by comparing the finite element simulation method via APDL and the analytical method via MATLAB. In addition, the sensitivity of the method to noise is investigated. The results indicate that the method accurately identifies cracks (single and multiple) with a minimum depth of 0.2 mm in various locations on subsea jumpers. This study may hold significant reference value for improving the safety and reliability of subsea jumpers.
{"title":"Subsea jumper damage detection based on fractal analysis and modal characteristics","authors":"Yan Li","doi":"10.21278/brod75201","DOIUrl":"https://doi.org/10.21278/brod75201","url":null,"abstract":"Subsea jumpers play a critical role in subsea oil and gas production. Structural damage such as cracks is inevitable in subsea jumpers due to the harsh marine environment (internal fluid flow corrosion, high temperature and pressure, etc.). However, the current research on damage detection and evaluation of subsea jumpers is limited, particularly in cases of slight damage. This study thus proposes a method to identify cracks in subsea jumpers based on the modal characteristics and fractal theory. The accuracy of the method is verified by comparing the finite element simulation method via APDL and the analytical method via MATLAB. In addition, the sensitivity of the method to noise is investigated. The results indicate that the method accurately identifies cracks (single and multiple) with a minimum depth of 0.2 mm in various locations on subsea jumpers. This study may hold significant reference value for improving the safety and reliability of subsea jumpers.","PeriodicalId":55594,"journal":{"name":"Brodogradnja","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140086363","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}
The decarbonisation of the maritime sector is one of the world’s priorities to reduce the volume of polluting emissions. The basis of this decarbonisation is the adaptation of existing ships to emission control regulations by means of transformations, installation of new equipment, development of new low-emission fuels and development of the infrastructure that makes the supply of this new generation of fuels feasible. In addition, hydrogen is the energy vector for all these new technologies, and its role over the next 30 years needs to be addressed. In a changing global situation such as the one we are currently experiencing; this article has the objective of making a review paper on the different fuels currently being used in the maritime sector and the existing alternatives. It also discusses the situation and the impact the current environmental situation has on the world ship order book, both in terms of legislation and economics. As a conclusion, the Liquefied Natural Gas (LNG) will have a very important role to play as a bridge between the current situation and the development of hydrogen technology. Hydrogen is an energy vector that can achieve the decarbonisation objectives by 2050. Storage problems, lack of infrastructures to supply it and the development of technology and regulations are the major challenges it will have to face. Biofuels also present a serious proposal for the decarbonisation of the sector, and the role of hydrogen in their composition, is essential to achieve green fuel generation.
{"title":"The decarbonisation of the maritime sector: Horizon 2050","authors":"José Miguel Mahía Prados","doi":"10.21278/brod75202","DOIUrl":"https://doi.org/10.21278/brod75202","url":null,"abstract":"The decarbonisation of the maritime sector is one of the world’s priorities to reduce the volume of polluting emissions. The basis of this decarbonisation is the adaptation of existing ships to emission control regulations by means of transformations, installation of new equipment, development of new low-emission fuels and development of the infrastructure that makes the supply of this new generation of fuels feasible. In addition, hydrogen is the energy vector for all these new technologies, and its role over the next 30 years needs to be addressed. In a changing global situation such as the one we are currently experiencing; this article has the objective of making a review paper on the different fuels currently being used in the maritime sector and the existing alternatives. It also discusses the situation and the impact the current environmental situation has on the world ship order book, both in terms of legislation and economics. As a conclusion, the Liquefied Natural Gas (LNG) will have a very important role to play as a bridge between the current situation and the development of hydrogen technology. Hydrogen is an energy vector that can achieve the decarbonisation objectives by 2050. Storage problems, lack of infrastructures to supply it and the development of technology and regulations are the major challenges it will have to face. Biofuels also present a serious proposal for the decarbonisation of the sector, and the role of hydrogen in their composition, is essential to achieve green fuel generation.","PeriodicalId":55594,"journal":{"name":"Brodogradnja","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140275735","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}
Ship collision avoidance has always been a concern and it is crucial for achieving safe navigation of ships at sea. There are many studies on ship collision avoidance in open water, but less attention on coastal waters considering the uncertainty of target ships due to the complexity of the environment and traffic flow. In this paper, collision avoidance decision-making research in coastal waters considering the uncertainty of target ships was proposed. Firstly, accurate ship trajectories are obtained by preprocessing the raw Automatic Identification System (AIS) data. Subsequently, the processed trajectories are clustered using the Ordering Points to Identify the Clustering Structure (OPTICS) algorithm and Hausdorff distance, acquiring a dataset for trajectory prediction of target ships. Then, a mixed Gaussian model is utilized to calculate the prior probability distribution of the prediction model, thus establishing a trajectory prediction model that considers the uncertainty of the target ship. Finally, ship maneuverability is simulated using the Mathematical Model Group (MMG) and Proportion Integration Differentiation (PID) models, and a collision avoidance decision-making model for ships is constructed. The proposed algorithm has been tested and verified in a case study. The results show that the approach effectively predicts the trajectory of the target ship and facilitates informed collision avoidance decision-making.
{"title":"Ship collision avoidance decision-making research in coastal waters considering uncertainty of target ships","authors":"Jianjie Gao, Yuquan Zhang","doi":"10.21278/brod75203","DOIUrl":"https://doi.org/10.21278/brod75203","url":null,"abstract":"Ship collision avoidance has always been a concern and it is crucial for achieving safe navigation of ships at sea. There are many studies on ship collision avoidance in open water, but less attention on coastal waters considering the uncertainty of target ships due to the complexity of the environment and traffic flow. In this paper, collision avoidance decision-making research in coastal waters considering the uncertainty of target ships was proposed. Firstly, accurate ship trajectories are obtained by preprocessing the raw Automatic Identification System (AIS) data. Subsequently, the processed trajectories are clustered using the Ordering Points to Identify the Clustering Structure (OPTICS) algorithm and Hausdorff distance, acquiring a dataset for trajectory prediction of target ships. Then, a mixed Gaussian model is utilized to calculate the prior probability distribution of the prediction model, thus establishing a trajectory prediction model that considers the uncertainty of the target ship. Finally, ship maneuverability is simulated using the Mathematical Model Group (MMG) and Proportion Integration Differentiation (PID) models, and a collision avoidance decision-making model for ships is constructed. The proposed algorithm has been tested and verified in a case study. The results show that the approach effectively predicts the trajectory of the target ship and facilitates informed collision avoidance decision-making.","PeriodicalId":55594,"journal":{"name":"Brodogradnja","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140090304","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}
During the design phase of an offshore unit, estimating the station-keeping capabilities of the dynamic positioning (DP) system is mandatory. This means, in conventional offshore applications, to determine the maximum sustainable wind speed as a function of the encounter heading, which the unit may counteract by employing the onboard actuators or mooring lines only. Besides the deterministic estimation of DP capability, it is possible to assess the operability of the DP system following a non-deterministic probabilistic process by employing the site-specific joint wind-wave distributions to model the environment. In such a case, the operability results from a Monte Carlo integration process. Here it is proposed to enhance the applicability of the probabilistic analysis of DP operability, investigating the application of a Quasi-Monte Carlo method. In this sense, the procedure uses quasi-random samplings following a Sobol sequence instead of employing random samples of the joint distributions. In this paper, the Quasi-Monte Carlo process is tested and compared on a reference ship, highlighting the improvements to the established probabilistic DP prediction concerning the number of calculations needed to estimate operability. The significant reduction of computational time makes the newly implemented method suitable for the early design stage applications.
{"title":"Probabilistic evaluation of dynamic positioning operability with a Quasi-Monte Carlo approach","authors":"Francesco Mauro","doi":"10.21278/brod75105","DOIUrl":"https://doi.org/10.21278/brod75105","url":null,"abstract":"During the design phase of an offshore unit, estimating the station-keeping capabilities of the dynamic positioning (DP) system is mandatory. This means, in conventional offshore applications, to determine the maximum sustainable wind speed as a function of the encounter heading, which the unit may counteract by employing the onboard actuators or mooring lines only. Besides the deterministic estimation of DP capability, it is possible to assess the operability of the DP system following a non-deterministic probabilistic process by employing the site-specific joint wind-wave distributions to model the environment. In such a case, the operability results from a Monte Carlo integration process. Here it is proposed to enhance the applicability of the probabilistic analysis of DP operability, investigating the application of a Quasi-Monte Carlo method. In this sense, the procedure uses quasi-random samplings following a Sobol sequence instead of employing random samples of the joint distributions. In this paper, the Quasi-Monte Carlo process is tested and compared on a reference ship, highlighting the improvements to the established probabilistic DP prediction concerning the number of calculations needed to estimate operability. The significant reduction of computational time makes the newly implemented method suitable for the early design stage applications.","PeriodicalId":55594,"journal":{"name":"Brodogradnja","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139125376","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}
With the frequent occurrence of ship explosion accidents at sea, the safety of ships and crews has attracted much attention. At present, the research on crew injury is relatively weak. Consequently, the current study constructs a numerical model of the ship structure-crew-blast flow field to investigate the discrepancies in injury response of crew members across different sitting postures. LS-DYNA software is used for simulation and direct analysis to evaluate the damage of crew members in different positions under 100 kg TNT equivalent and 2 m blast distance conditions, and the relationship between different explosive equivalents and crew damage is analyzed. The results demonstrate that for crew members situated in working compartment, the injuries incurred across different sitting postures also differed. The lower leg and foot sections were at greater injury risks, while the head area was associated with minimal damage risks. Altering upper body postures of the crew human body had only a very small impact on lower extremity injuries. Moreover, positive correlations were exhibited between explosive equivalents and crew injury values. The research findings may offer references for injury analysis and protective device design of naval personnel.
随着海上船舶爆炸事故的频繁发生，船舶和船员的安全问题备受关注。目前，对船员伤害的研究相对薄弱。因此，本研究构建了一个船舶结构-船员-爆炸流场的数值模型，以研究船员在不同坐姿下的伤害反应差异。采用 LS-DYNA 软件进行模拟和直接分析，评估了 100 kg TNT 当量和 2 m 爆炸距离条件下不同坐姿船员的损伤情况，并分析了不同爆炸当量与船员损伤之间的关系。结果表明，对于工作舱内的乘员，不同坐姿造成的伤害也不同。小腿和脚部受到伤害的风险更大，而头部受到伤害的风险最小。改变船员的上半身姿势对下肢受伤的影响很小。此外，爆炸当量与船员受伤值之间呈正相关。研究结果可为海军人员的伤害分析和防护装置设计提供参考。
{"title":"Analysis of damage to ship personnel in different seated postures by near-field underwater explosions","authors":"Kai Li","doi":"10.21278/brod75107","DOIUrl":"https://doi.org/10.21278/brod75107","url":null,"abstract":"With the frequent occurrence of ship explosion accidents at sea, the safety of ships and crews has attracted much attention. At present, the research on crew injury is relatively weak. Consequently, the current study constructs a numerical model of the ship structure-crew-blast flow field to investigate the discrepancies in injury response of crew members across different sitting postures. LS-DYNA software is used for simulation and direct analysis to evaluate the damage of crew members in different positions under 100 kg TNT equivalent and 2 m blast distance conditions, and the relationship between different explosive equivalents and crew damage is analyzed. The results demonstrate that for crew members situated in working compartment, the injuries incurred across different sitting postures also differed. The lower leg and foot sections were at greater injury risks, while the head area was associated with minimal damage risks. Altering upper body postures of the crew human body had only a very small impact on lower extremity injuries. Moreover, positive correlations were exhibited between explosive equivalents and crew injury values. The research findings may offer references for injury analysis and protective device design of naval personnel.","PeriodicalId":55594,"journal":{"name":"Brodogradnja","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139128099","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}
In this paper, the slamming loads and structural response of an aluminium flat stiffened-plate structure during calm water entry considering the hydroelasticity effects are studied by a partitioned CFD-FEM two-way coupled method. The target structure is simplified as one segment of an idealized ship grillage structure, comprising flat plate and stiffeners. The typical numerical results are analyzed such as vertical displacement, velocity, acceleration, impact loads, and structural stress of the flexible flat bottom grillage structure considering the hydroelasticity effect and air cushion effect in different free fall height conditions. Drop test results of the same structure and other existing numerical simulation data by both coupled and uncoupled solutions in the literature are used for comparison with the present numerical simulation results. This study provides a practical means to simulate the slamming behaviour and structural response of ship structures, which is useful for predicting ship hull stiffened panel loads and related structural design.
{"title":"CFD-FEM simulation of water entry of aluminium flat stiffened plate structure considering the effects of hydroelasticity","authors":"Jialong Jiao","doi":"10.21278/brod75108","DOIUrl":"https://doi.org/10.21278/brod75108","url":null,"abstract":"In this paper, the slamming loads and structural response of an aluminium flat stiffened-plate structure during calm water entry considering the hydroelasticity effects are studied by a partitioned CFD-FEM two-way coupled method. The target structure is simplified as one segment of an idealized ship grillage structure, comprising flat plate and stiffeners. The typical numerical results are analyzed such as vertical displacement, velocity, acceleration, impact loads, and structural stress of the flexible flat bottom grillage structure considering the hydroelasticity effect and air cushion effect in different free fall height conditions. Drop test results of the same structure and other existing numerical simulation data by both coupled and uncoupled solutions in the literature are used for comparison with the present numerical simulation results. This study provides a practical means to simulate the slamming behaviour and structural response of ship structures, which is useful for predicting ship hull stiffened panel loads and related structural design.","PeriodicalId":55594,"journal":{"name":"Brodogradnja","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139129587","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}
As general cargo ships (GCSs) hold certain advantages over more mainstream shipping services, GCSs have a considerable degree of importance in the shipping market. This paper focuses on the use of risk evaluation procedures to perform empirical analysis of the operational risk faced by GCS operators, which is a subject that has garnered relatively little academic attention. After identifying risk factors, four risk aspects and 16 operational risk factors are determined and used to construct an Analytic Hierarchy Process (AHP)-based risk matrix evaluation model. An expert questionnaire addressing both subjective and objective facets is then used to perform evaluation of the model, enabling conversion of the relative weights to risk scales. Lastly, the determination of each risk factor’s risk areas allows the proposal of risk management strategies. The results indicate that four of the risk factors are in the high risk area; these consisted of the loading stage factor “delays at port of loading,” the laden voyage stage factor “poor stowage and securing,” the laden voyage stage factor “perils of the sea,” and the discharging stage factor “delays at port of discharge.” This paper also proposes risk management strategies on the basis of the experts’ recommendations, and its findings can provide shipowners and charterers with a reference for the drafting of risk clauses when entering into a charter party.
{"title":"An evaluation of operational risks for general cargo ship operators","authors":"Ji-Feng Ding","doi":"10.21278/brod75101","DOIUrl":"https://doi.org/10.21278/brod75101","url":null,"abstract":"As general cargo ships (GCSs) hold certain advantages over more mainstream shipping services, GCSs have a considerable degree of importance in the shipping market. This paper focuses on the use of risk evaluation procedures to perform empirical analysis of the operational risk faced by GCS operators, which is a subject that has garnered relatively little academic attention. After identifying risk factors, four risk aspects and 16 operational risk factors are determined and used to construct an Analytic Hierarchy Process (AHP)-based risk matrix evaluation model. An expert questionnaire addressing both subjective and objective facets is then used to perform evaluation of the model, enabling conversion of the relative weights to risk scales. Lastly, the determination of each risk factor’s risk areas allows the proposal of risk management strategies. The results indicate that four of the risk factors are in the high risk area; these consisted of the loading stage factor “delays at port of loading,” the laden voyage stage factor “poor stowage and securing,” the laden voyage stage factor “perils of the sea,” and the discharging stage factor “delays at port of discharge.” This paper also proposes risk management strategies on the basis of the experts’ recommendations, and its findings can provide shipowners and charterers with a reference for the drafting of risk clauses when entering into a charter party.","PeriodicalId":55594,"journal":{"name":"Brodogradnja","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139130005","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}
This study proposes a robust optimization method for waterborne emergency resource allocation in inland waterways that addresses the uncertainties and mismatches between supply and demand. To accomplish this, we integrate the risk evaluation of maritime with a robust optimization model and employ the Entropy Weighted Method (EWM)-Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)-Analytic Hierarchy Process (AHP) method to evaluate the risk of various areas. The approach enables exploration of the relationship between maritime risk and emergency resource allocation strategy. The robust optimization method is used to deal with uncertainty and derive the robust counterpart of the proposed model. We establish an emergency resource allocation model that considers both the economy and timeliness of emergency resource allocation. We construct an optimization model and transform it into an easily solvable robust counterpart model. The results demonstrate that the proposed method can adapt to real-world scenarios, and effectively optimize the configuration effect while improving rescue efficiency under reasonable resource allocation. Specifically, the proportion of rescue time saved ranges from 28.52% to 92.60%, and the proportion of total cost saved is 95.82%. Our approach has significant potential to provide a valuable reference for decision-making related to emergency resource allocation in maritime management.
{"title":"Robust optimization method of emergency resource allocation for risk management in inland waterways","authors":"Quandang Ma","doi":"10.21278/brod75103","DOIUrl":"https://doi.org/10.21278/brod75103","url":null,"abstract":"This study proposes a robust optimization method for waterborne emergency resource allocation in inland waterways that addresses the uncertainties and mismatches between supply and demand. To accomplish this, we integrate the risk evaluation of maritime with a robust optimization model and employ the Entropy Weighted Method (EWM)-Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)-Analytic Hierarchy Process (AHP) method to evaluate the risk of various areas. The approach enables exploration of the relationship between maritime risk and emergency resource allocation strategy. The robust optimization method is used to deal with uncertainty and derive the robust counterpart of the proposed model. We establish an emergency resource allocation model that considers both the economy and timeliness of emergency resource allocation. We construct an optimization model and transform it into an easily solvable robust counterpart model. The results demonstrate that the proposed method can adapt to real-world scenarios, and effectively optimize the configuration effect while improving rescue efficiency under reasonable resource allocation. Specifically, the proportion of rescue time saved ranges from 28.52% to 92.60%, and the proportion of total cost saved is 95.82%. Our approach has significant potential to provide a valuable reference for decision-making related to emergency resource allocation in maritime management.","PeriodicalId":55594,"journal":{"name":"Brodogradnja","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139130012","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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