The Householder transformation-norm structure function in L2 vector space of linear algebra is introduced, and the edge enhancement for remote sensing images is realized. The experiment result is compared with traditi...The Householder transformation-norm structure function in L2 vector space of linear algebra is introduced, and the edge enhancement for remote sensing images is realized. The experiment result is compared with traditional Laplacian and Sobel edge enhancements and it shows that the effect of the new method is better than that of the traditional algorithms.展开更多
Several theorems on closed (resp. open) covering properties of H-spaces are obtained which improve and generalize the corresponding results of Sperner, Klee, Alexandroff-Pasynkoff, Berge, Ghouila-Houri, Danzer-Grunbau...Several theorems on closed (resp. open) covering properties of H-spaces are obtained which improve and generalize the corresponding results of Sperner, Klee, Alexandroff-Pasynkoff, Berge, Ghouila-Houri, Danzer-Grunbaum-Klee, Ky Fan, Shih-Tan, Horvath and Lassonde. As application an almost fixed point theorem for lower semi-continuous map in l.c.-spaces and a generalization of Tychonoffs fixed point theorem are proved in l.c.-spaces which improve those results of Ky Fan and Horvath.展开更多
We construct in ZFC(the Zermelo-Fraenkel system with choice) an L topological vector space—a topological vector space that is an L space—and an L field—a topological field that is an L space. This generalizes earli...We construct in ZFC(the Zermelo-Fraenkel system with choice) an L topological vector space—a topological vector space that is an L space—and an L field—a topological field that is an L space. This generalizes earlier results in L spaces and L groups.展开更多
An analytical evaluation method for output waveform quality of space vector pulse width modulation(PWM)strategies applied in neutral⁃point⁃clamped three⁃level converter(3L⁃NPC)is proposed in this paper.Low frequency e...An analytical evaluation method for output waveform quality of space vector pulse width modulation(PWM)strategies applied in neutral⁃point⁃clamped three⁃level converter(3L⁃NPC)is proposed in this paper.Low frequency error caused by neutral point voltage ripple and high frequency error introduced by space vector synthesis were both taken into account,and the unified error model of output current ripple was established.By taking continuous and discontinuous modulation strategies as examples,the unified error model was validated through Fourier analysis of the experimental results.The proposed evaluation method will be helpful for the switching sequence optimization and the modulation strategy selection.展开更多
基金Funded by the National Natural Science Foundation of China(No.40571100).
文摘The Householder transformation-norm structure function in L2 vector space of linear algebra is introduced, and the edge enhancement for remote sensing images is realized. The experiment result is compared with traditional Laplacian and Sobel edge enhancements and it shows that the effect of the new method is better than that of the traditional algorithms.
基金This project partially supported by National Natural Science Foundation of ChinaThis work was partially supported by NSERC of Canada under grant A-8096
文摘Several theorems on closed (resp. open) covering properties of H-spaces are obtained which improve and generalize the corresponding results of Sperner, Klee, Alexandroff-Pasynkoff, Berge, Ghouila-Houri, Danzer-Grunbaum-Klee, Ky Fan, Shih-Tan, Horvath and Lassonde. As application an almost fixed point theorem for lower semi-continuous map in l.c.-spaces and a generalization of Tychonoffs fixed point theorem are proved in l.c.-spaces which improve those results of Ky Fan and Horvath.
基金supported by National Natural Science Foundation of China(Grant No.11901562)A Program of the Chinese Academy of Sciencessupported by National Natural Science Foundation of China(Grant No.11871464)。
文摘We construct in ZFC(the Zermelo-Fraenkel system with choice) an L topological vector space—a topological vector space that is an L space—and an L field—a topological field that is an L space. This generalizes earlier results in L spaces and L groups.
基金National Natural Science Foundation of China(Grant Nos.51807140 and 51690183).
文摘An analytical evaluation method for output waveform quality of space vector pulse width modulation(PWM)strategies applied in neutral⁃point⁃clamped three⁃level converter(3L⁃NPC)is proposed in this paper.Low frequency error caused by neutral point voltage ripple and high frequency error introduced by space vector synthesis were both taken into account,and the unified error model of output current ripple was established.By taking continuous and discontinuous modulation strategies as examples,the unified error model was validated through Fourier analysis of the experimental results.The proposed evaluation method will be helpful for the switching sequence optimization and the modulation strategy selection.
