In this study,a moored array optimization tool(MAOT)was developed and applied to the South China Sea(SCS)with a focus on three-dimensional temperature and salinity observations.Application of the MAOT involves two ste...In this study,a moored array optimization tool(MAOT)was developed and applied to the South China Sea(SCS)with a focus on three-dimensional temperature and salinity observations.Application of the MAOT involves two steps:(1)deriving a set of optimal arrays that are independent of each other for different variables at different depths based on an empirical orthogonal function method,and(2)consolidating these arrays using a K-center clustering algorithm.Compared with the assumed initial array consisting of 17 mooring sites located on a 3°×3°horizontal grid,the consolidated array improved the observing ability for three-dimensional temperature and salinity in the SCS with optimization efficiencies of 19.03%and 21.38%,respectively.Experiments with an increased number of moored sites showed that the most cost-effective option is a total of 20 moorings,improving the observing ability with optimization efficiencies up to 26.54%for temperature and 27.25%for salinity.The design of an objective array relies on the ocean phenomenon of interest and its spatial and temporal scales.In this study,we focus on basin-scale variations in temperature and salinity in the SCS,and thus our consolidated array may not well resolve mesoscale processes.The MAOT can be extended to include other variables and multi-scale variability and can be applied to other regions.展开更多
The clustering problem of big data in the era of artificial intelligence has been widely studied.Because of the huge amount of data,distributed algorithms are often used to deal with big data problems.The distributed ...The clustering problem of big data in the era of artificial intelligence has been widely studied.Because of the huge amount of data,distributed algorithms are often used to deal with big data problems.The distributed computing model has an attractive feature:it can handle massive datasets that cannot be put into the main memory.On the other hand,since many decisions are made automatically by machines in today’s society,algorithm fairness is also an important research area of machine learning.In this paper,we study two fair clustering problems:the centralized fair k-center problem with outliers and the distributed fair k-center problem with outliers.For these two problems,we have designed corresponding constant approximation ratio algorithms.The theoretical proof and analysis of the approximation ratio,and the running space of the algorithm are given.展开更多
基金The National Key Research and Development Program of China under contract No.2019YFC1408400the National Natural Science Foundation of China under contract No.41876029.
文摘In this study,a moored array optimization tool(MAOT)was developed and applied to the South China Sea(SCS)with a focus on three-dimensional temperature and salinity observations.Application of the MAOT involves two steps:(1)deriving a set of optimal arrays that are independent of each other for different variables at different depths based on an empirical orthogonal function method,and(2)consolidating these arrays using a K-center clustering algorithm.Compared with the assumed initial array consisting of 17 mooring sites located on a 3°×3°horizontal grid,the consolidated array improved the observing ability for three-dimensional temperature and salinity in the SCS with optimization efficiencies of 19.03%and 21.38%,respectively.Experiments with an increased number of moored sites showed that the most cost-effective option is a total of 20 moorings,improving the observing ability with optimization efficiencies up to 26.54%for temperature and 27.25%for salinity.The design of an objective array relies on the ocean phenomenon of interest and its spatial and temporal scales.In this study,we focus on basin-scale variations in temperature and salinity in the SCS,and thus our consolidated array may not well resolve mesoscale processes.The MAOT can be extended to include other variables and multi-scale variability and can be applied to other regions.
基金This work was supported by the National Natural Science Foundation of China(Nos.12131003,11771386,and 11728104)the Beijing Natural Science Foundadtion Project(No.Z200002)+2 种基金the General Research Projects of Beijing Educations Committee in China(No.KM201910005013)the Natural Sciences and Engineering Research Council of Canada(NSERC)(No.06446)the General Program of Science and Technology Development Project of Beijing Municipal Education Commission(No.KM201810005005).
文摘The clustering problem of big data in the era of artificial intelligence has been widely studied.Because of the huge amount of data,distributed algorithms are often used to deal with big data problems.The distributed computing model has an attractive feature:it can handle massive datasets that cannot be put into the main memory.On the other hand,since many decisions are made automatically by machines in today’s society,algorithm fairness is also an important research area of machine learning.In this paper,we study two fair clustering problems:the centralized fair k-center problem with outliers and the distributed fair k-center problem with outliers.For these two problems,we have designed corresponding constant approximation ratio algorithms.The theoretical proof and analysis of the approximation ratio,and the running space of the algorithm are given.
