In order to effectively analyse the multivariate time series data of complex process,a generic reconstruction technology based on reduction theory of rough sets was proposed,Firstly,the phase space of multivariate tim...In order to effectively analyse the multivariate time series data of complex process,a generic reconstruction technology based on reduction theory of rough sets was proposed,Firstly,the phase space of multivariate time series was originally reconstructed by a classical reconstruction technology.Then,the original decision-table of rough set theory was set up according to the embedding dimensions and time-delays of the original reconstruction phase space,and the rough set reduction was used to delete the redundant dimensions and irrelevant variables and to reconstruct the generic phase space,Finally,the input vectors for the prediction of multivariate time series were extracted according to generic reconstruction results to identify the parameters of prediction model.Verification results show that the developed reconstruction method leads to better generalization ability for the prediction model and it is feasible and worthwhile for application.展开更多
The boron nitride fibers were heated at the range of 600-1400℃ in flowing nitrogen and air, respectively, and the effects of heat treatment on the structure, composition and morphology of BN fibers were studied. The ...The boron nitride fibers were heated at the range of 600-1400℃ in flowing nitrogen and air, respectively, and the effects of heat treatment on the structure, composition and morphology of BN fibers were studied. The results showed that BN fibers exhibited smooth surfaces, and that t-BN was the main phase with a little B203 included. After heat treatment at 1400℃ in nitrogen atmosphere, the fibers displayed rough surfaces with little change in mass. Better crystallinity was obtained with the increasing temperature. During heat treatment in air, the fibers were oxidized severely as the temperature went up, especially at 1400℃. The volatilization of B203, HBO2 and H3BO3 led to the pores on the surfaces of the fibers, while the boron oxide glaze and nitrogen gas produced during the oxidation process protected the fibers from further oxidation.展开更多
基金Project(61025015) supported by the National Natural Science Funds for Distinguished Young Scholars of ChinaProject(21106036) supported by the National Natural Science Foundation of China+2 种基金Project(200805331103) supported by Research Fund for the Doctoral Program of Higher Education of ChinaProject(NCET-08-0576) supported by Program for New Century Excellent Talents in Universities of ChinaProject(11B038) supported by Scientific Research Fund for the Excellent Youth Scholars of Hunan Provincial Education Department,China
文摘In order to effectively analyse the multivariate time series data of complex process,a generic reconstruction technology based on reduction theory of rough sets was proposed,Firstly,the phase space of multivariate time series was originally reconstructed by a classical reconstruction technology.Then,the original decision-table of rough set theory was set up according to the embedding dimensions and time-delays of the original reconstruction phase space,and the rough set reduction was used to delete the redundant dimensions and irrelevant variables and to reconstruct the generic phase space,Finally,the input vectors for the prediction of multivariate time series were extracted according to generic reconstruction results to identify the parameters of prediction model.Verification results show that the developed reconstruction method leads to better generalization ability for the prediction model and it is feasible and worthwhile for application.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50902150, 90916019)the Graduate Innovation Foundation of the National University of Defense Technology (Grant No. S100103)
文摘The boron nitride fibers were heated at the range of 600-1400℃ in flowing nitrogen and air, respectively, and the effects of heat treatment on the structure, composition and morphology of BN fibers were studied. The results showed that BN fibers exhibited smooth surfaces, and that t-BN was the main phase with a little B203 included. After heat treatment at 1400℃ in nitrogen atmosphere, the fibers displayed rough surfaces with little change in mass. Better crystallinity was obtained with the increasing temperature. During heat treatment in air, the fibers were oxidized severely as the temperature went up, especially at 1400℃. The volatilization of B203, HBO2 and H3BO3 led to the pores on the surfaces of the fibers, while the boron oxide glaze and nitrogen gas produced during the oxidation process protected the fibers from further oxidation.
