To fully display the modeling mechanism of the novelfractional order grey model （FGM （q,1））, this paper decomposesthe data matrix of the model into the mean generation matrix, theaccumulative generation matrix and...To fully display the modeling mechanism of the novelfractional order grey model （FGM （q,1））, this paper decomposesthe data matrix of the model into the mean generation matrix, theaccumulative generation matrix and the raw data matrix, whichare consistent with the fractional order accumulative grey model（FAGM （1,1））. Following this, this paper decomposes the accumulativedata difference matrix into the accumulative generationmatrix, the q-order reductive accumulative matrix and the rawdata matrix, and then combines the least square method, findingthat the differential order affects the model parameters only byaffecting the formation of differential sequences. This paper thensummarizes matrix decomposition of some special sequences,such as the sequence generated by the strengthening and weakeningoperators, the jumping sequence, and the non-equidistancesequence. Finally, this paper expresses the influences of the rawdata transformation, the accumulation sequence transformation,and the differential matrix transformation on the model parametersas matrices, and takes the non-equidistance sequence as an exampleto show the modeling mechanism.展开更多
The so-called "green ship" is being regarded as a potential solution to the problems that the shipping industry faces, such as energy conservation and environmental protection. Some new features, such as int...The so-called "green ship" is being regarded as a potential solution to the problems that the shipping industry faces, such as energy conservation and environmental protection. Some new features, such as integrated renewable energy application, biomimetic materials, and antifriction and wear resistant coating have been accepted as the typical characteristics of a green ship, but the tribology problems involved in these domains have not been precisely redefined yet. Further, the related research work is generally focused on the technology or material itself, but not on the integration of the applicable object or green ship, marine environment, and tribological systematical analysis from the viewpoint of the energy efficiency design index(EEDI) and ship energy efficiency management plan(SEEMP) improvements. Aiming at the tribology problems of the green ship, this paper reviews the research status of this issue from three specific domains, which are the tribology problems of the renewable energy system, tribological research for hull resistance reduction, and energy efficiency enhancement. Some typical tribological problems in the sail-auxiliary system are discussed, along with the solar photovoltaic system and hull drag reduction in traditional marine mechanical equipment. Correspondingly, four domains that should be further considered for the future development target of the green ship are prospected.展开更多
With the development of green tribology in the shipping industry,the application of water lubrication gradually replaces oil lubrication in stern bearings and thrust bearings.In terms of large-scale and high-speed shi...With the development of green tribology in the shipping industry,the application of water lubrication gradually replaces oil lubrication in stern bearings and thrust bearings.In terms of large-scale and high-speed ships,water-lubricated bearings with high performance are more strictly required.However,due to the lubricating medium,water-lubricated bearings have many problems such as friction,wear,vibration,noise,etc.This review focuses on the performance of marine water-lubricated bearings and their failure prevention mechanism.Furthermore,the research of marine water-lubricated bearings is reviewed by discussing its lubrication principle,test technology,friction and wear mechanism,and friction noise generation mechanism.The performance enhancement methods have been overviewed from structure optimization and material modification.Finally,the potential problems and the perspective of water-lubricated bearings are given in detail.展开更多
The use of condition monitoring and fault diagnosis(CMFD)in marine power systems significantly influences ship safety.This study divides the development of CMFD for marine power systems into three periods and reviews ...The use of condition monitoring and fault diagnosis(CMFD)in marine power systems significantly influences ship safety.This study divides the development of CMFD for marine power systems into three periods and reviews the content,state and limitations of CMFD research for each period.According to the research achievements and engineering experience of the authors’team,typical application cases are introduced for CMFD in ships,including CMFD platforms on engineering ships,salvage ships,container ships and ro-ro ships powered by solar photovoltaic systems.Finally,prospective research directions are proposed for CMFD in marine power systems,considering the research status of CMFD and the trend toward intelligent and eco-friendly ships.展开更多
This paper discusses the predefined practical finite-time(PPFT)dynamic positioning(DP)control problem for DP vessels subject to internal/external uncertainties.Those heterogeneity uncertainties are handled by a separa...This paper discusses the predefined practical finite-time(PPFT)dynamic positioning(DP)control problem for DP vessels subject to internal/external uncertainties.Those heterogeneity uncertainties are handled by a separate-type treatment approach.The finite-time(FT)DP control is fulfilled by a predefined FT function on the basis of a time-based generator(TBG).Under the dynamic surface control together with the TBG design framework,the convergence time and control accuracy of the DP system can be determined by the designer offline.Meanwhile,the virtual derivation and computational burden problems are dissolved by using a first-order filter and virtual parameter learning technique.To reduce mechanical wear,an event-triggering protocol between the control law and the actuator is built to reduce the operating frequency of the actuator.An event-triggered neuroadaptive PPFT control scheme is presented for DP vessels.The stability of the closed-loop DP control systems is validated via the Lyapunov theorem.Approach efficiency is confirmed by numerical examples.展开更多
Shipping is perhaps themost international of all the world’s great industries and one of the most dangerous.It is essential to study maritime safety and take reasonable measurements to ensure the security of life and...Shipping is perhaps themost international of all the world’s great industries and one of the most dangerous.It is essential to study maritime safety and take reasonable measurements to ensure the security of life and property.With the rapid development of Artificial Intelligence,industrial upgrading is undergoing a change in the maritime industry,where many techniques have been developed to enhance maritime safety and improve the automation and intelligence of ships,equipment,and infrastructure.展开更多
Recognizing the specific complexities of vessel traffic flow,this comprehensive survey exclusively addresses the predictive modelling in maritime transportation,tracing the evolution from conventional statistical appr...Recognizing the specific complexities of vessel traffic flow,this comprehensive survey exclusively addresses the predictive modelling in maritime transportation,tracing the evolution from conventional statistical approaches to modern artificial intelligence(AI)techniques.The survey examines a broad range of predictive targets,including vessel volume,trajectories,velocities,destinations and traffic patterns.Through bibliometric analysis utilizing Citespace,the central research themes and technological trends characterizing the vessel traffic flow prediction domain have been identified and discussed.Our analysis indicates a clear trend towards AI-based models,highlighting their increasing dominance in enhancing predictive accuracy and efficiency.Additionally,we highlight persistent challenges,such as the integration of large datasets with traffic flow models and the critical need for real-time data analytics.The survey concludes with insights into the future of vessel traffic flow prediction research,emphasizing the potential of hybrid models that combine deep learning with statistical learning to enable more sophisticated predictive analytics to be performed.This review aims to serve as a guide for both academics and practitioners looking to maximize the use of predictive modelling in the maritime traffic sector.展开更多
基金supported by the National Natural Science Foundation of China(5147915151279149+2 种基金71540027)the China Postdoctoral Science Foundation Special Foundation Project(2013T607552012M521487)
文摘To fully display the modeling mechanism of the novelfractional order grey model （FGM （q,1））, this paper decomposesthe data matrix of the model into the mean generation matrix, theaccumulative generation matrix and the raw data matrix, whichare consistent with the fractional order accumulative grey model（FAGM （1,1））. Following this, this paper decomposes the accumulativedata difference matrix into the accumulative generationmatrix, the q-order reductive accumulative matrix and the rawdata matrix, and then combines the least square method, findingthat the differential order affects the model parameters only byaffecting the formation of differential sequences. This paper thensummarizes matrix decomposition of some special sequences,such as the sequence generated by the strengthening and weakeningoperators, the jumping sequence, and the non-equidistancesequence. Finally, this paper expresses the influences of the rawdata transformation, the accumulation sequence transformation,and the differential matrix transformation on the model parametersas matrices, and takes the non-equidistance sequence as an exampleto show the modeling mechanism.
基金supported by National Natural Science Foundation of China (Grant Nos. 51422507 and 51509195)
文摘The so-called "green ship" is being regarded as a potential solution to the problems that the shipping industry faces, such as energy conservation and environmental protection. Some new features, such as integrated renewable energy application, biomimetic materials, and antifriction and wear resistant coating have been accepted as the typical characteristics of a green ship, but the tribology problems involved in these domains have not been precisely redefined yet. Further, the related research work is generally focused on the technology or material itself, but not on the integration of the applicable object or green ship, marine environment, and tribological systematical analysis from the viewpoint of the energy efficiency design index(EEDI) and ship energy efficiency management plan(SEEMP) improvements. Aiming at the tribology problems of the green ship, this paper reviews the research status of this issue from three specific domains, which are the tribology problems of the renewable energy system, tribological research for hull resistance reduction, and energy efficiency enhancement. Some typical tribological problems in the sail-auxiliary system are discussed, along with the solar photovoltaic system and hull drag reduction in traditional marine mechanical equipment. Correspondingly, four domains that should be further considered for the future development target of the green ship are prospected.
基金financially supported by the National Key R&D Program of China(No.2018YFE0197600)National Natural Science Foundation of China(No.52071244).
文摘With the development of green tribology in the shipping industry,the application of water lubrication gradually replaces oil lubrication in stern bearings and thrust bearings.In terms of large-scale and high-speed ships,water-lubricated bearings with high performance are more strictly required.However,due to the lubricating medium,water-lubricated bearings have many problems such as friction,wear,vibration,noise,etc.This review focuses on the performance of marine water-lubricated bearings and their failure prevention mechanism.Furthermore,the research of marine water-lubricated bearings is reviewed by discussing its lubrication principle,test technology,friction and wear mechanism,and friction noise generation mechanism.The performance enhancement methods have been overviewed from structure optimization and material modification.Finally,the potential problems and the perspective of water-lubricated bearings are given in detail.
基金support from the NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization(grant no.U1709215)the NSFC(grant nos 52071241,61903108)the Natural Science Foundation of Zhejiang Province(grant no.LY21F030011).
文摘The use of condition monitoring and fault diagnosis(CMFD)in marine power systems significantly influences ship safety.This study divides the development of CMFD for marine power systems into three periods and reviews the content,state and limitations of CMFD research for each period.According to the research achievements and engineering experience of the authors’team,typical application cases are introduced for CMFD in ships,including CMFD platforms on engineering ships,salvage ships,container ships and ro-ro ships powered by solar photovoltaic systems.Finally,prospective research directions are proposed for CMFD in marine power systems,considering the research status of CMFD and the trend toward intelligent and eco-friendly ships.
基金supported in part by the National Natural Science Foundation of China(52022073,62073251 and 52261160383)in part by the Excellent Youth Foundation of Hubei Scientific Committee(2020CFA055)+4 种基金in part by the Natural Science Foundation of Zhejiang Province(LY21E090005)in part by the Innovation Research Team Project of the Hainan Natural Science Foundation(722CXTD518)in part by the Knowledge Innovation Program of Wuhan-Basic Research(2022010801010181)in part by the Science and Technology Project of Zhoushan(2022C41006)in part by the Hubei Key Laboratory of Inland Shipping Technology(NHHY2020004).
文摘This paper discusses the predefined practical finite-time(PPFT)dynamic positioning(DP)control problem for DP vessels subject to internal/external uncertainties.Those heterogeneity uncertainties are handled by a separate-type treatment approach.The finite-time(FT)DP control is fulfilled by a predefined FT function on the basis of a time-based generator(TBG).Under the dynamic surface control together with the TBG design framework,the convergence time and control accuracy of the DP system can be determined by the designer offline.Meanwhile,the virtual derivation and computational burden problems are dissolved by using a first-order filter and virtual parameter learning technique.To reduce mechanical wear,an event-triggering protocol between the control law and the actuator is built to reduce the operating frequency of the actuator.An event-triggered neuroadaptive PPFT control scheme is presented for DP vessels.The stability of the closed-loop DP control systems is validated via the Lyapunov theorem.Approach efficiency is confirmed by numerical examples.
文摘Shipping is perhaps themost international of all the world’s great industries and one of the most dangerous.It is essential to study maritime safety and take reasonable measurements to ensure the security of life and property.With the rapid development of Artificial Intelligence,industrial upgrading is undergoing a change in the maritime industry,where many techniques have been developed to enhance maritime safety and improve the automation and intelligence of ships,equipment,and infrastructure.
基金supported in part by the National Key Research and Development Program of China(Grant No.2023YFC3010803)in part by the National Natural Science Foundation of China(Grant Nos.52272424 and 52372320)+1 种基金in part by the Key Research and Development Program of Hubei Province of China(Grant No.2023BCB123)in part by the Fundamental Research Funds for the Central Universities(Grant No.104972024KFYd0039).
文摘Recognizing the specific complexities of vessel traffic flow,this comprehensive survey exclusively addresses the predictive modelling in maritime transportation,tracing the evolution from conventional statistical approaches to modern artificial intelligence(AI)techniques.The survey examines a broad range of predictive targets,including vessel volume,trajectories,velocities,destinations and traffic patterns.Through bibliometric analysis utilizing Citespace,the central research themes and technological trends characterizing the vessel traffic flow prediction domain have been identified and discussed.Our analysis indicates a clear trend towards AI-based models,highlighting their increasing dominance in enhancing predictive accuracy and efficiency.Additionally,we highlight persistent challenges,such as the integration of large datasets with traffic flow models and the critical need for real-time data analytics.The survey concludes with insights into the future of vessel traffic flow prediction research,emphasizing the potential of hybrid models that combine deep learning with statistical learning to enable more sophisticated predictive analytics to be performed.This review aims to serve as a guide for both academics and practitioners looking to maximize the use of predictive modelling in the maritime traffic sector.
