A novel scheme for scalable video coding using three-band lifting-based motion-compensated transform is presented in this article. A series of flexible three-band motion-compensated lifting steps are used to implement...A novel scheme for scalable video coding using three-band lifting-based motion-compensated transform is presented in this article. A series of flexible three-band motion-compensated lifting steps are used to implement the temporal wavelet transform, which provide improved compression performance by selecting specific motion model according to real video sequences, and offer higher temporal scalability flexibility by using three-band lifting steps. The experimental results compared with motion picture expert group （MPEG）-4 codec concerning standard video sequences demonstrate the effectiveness of the method.展开更多
Dissipative solitons have been realized in mode-locked fiber lasers in the theoretical framework of the Ginzburg±Landau equation and have significantly improved the pulse energy and peak power levels of such lase...Dissipative solitons have been realized in mode-locked fiber lasers in the theoretical framework of the Ginzburg±Landau equation and have significantly improved the pulse energy and peak power levels of such lasers.It is interesting to explore whether dissipative solitons exist in optical parametric oscillators in the framework of three-wave coupling equations in order to substantially increase the performance of optical parametric oscillators.Here,we demonstrate a temporalfiltering dissipative soliton in a synchronously pumped optical parametric oscillator.The temporal-gain filtering of the pump pulse combined with strong cascading nonlinearity and dispersion in the optical parametric oscillator enables the generation of a broad spectrum with a nearly linear chirp;consequently,a significantly compressed pulse and high peak power can be realized after dechirping outside the cavity.Furthermore,we realized,for the first time,dissipative solitons in an optical system with a negative nonlinear phase shift and anomalous dispersion,extending the parameter region of dissipative solitons.The findings may open a new research block for dissipative solitons and provide new opportunities for mid-infrared ultrafast science.展开更多
This research demonstrated quantitative methods of geospatial analysis applicable to carbon sequestration and storage in the conterminous United Sates. We identified national-scale NEP （net ecosystem production） cha...This research demonstrated quantitative methods of geospatial analysis applicable to carbon sequestration and storage in the conterminous United Sates. We identified national-scale NEP （net ecosystem production） changes for conversions to and from crop, and land in frequent conversion among forest, wetland, pasture and rangeland. The trend showed an increase in the margins of the Corn Belt states and coincided with land conversion from previous non-cropland to cropland in the United States. This research will not only improve the engineering understanding of carbon dioxide removal options involving the terrestrial biosphere, but will also inform decision-making in the carbon emission impacts. Therefore, it will provide a spatio-temporal reference for analyzing the national-level carbon exchange systems in the United States.展开更多
基金supported by the National Natural Science Foundation of China (60672132).
文摘A novel scheme for scalable video coding using three-band lifting-based motion-compensated transform is presented in this article. A series of flexible three-band motion-compensated lifting steps are used to implement the temporal wavelet transform, which provide improved compression performance by selecting specific motion model according to real video sequences, and offer higher temporal scalability flexibility by using three-band lifting steps. The experimental results compared with motion picture expert group （MPEG）-4 codec concerning standard video sequences demonstrate the effectiveness of the method.
基金the National Natural Science Foundation of China(Nos.61675130,62075126 and 91850203)。
文摘Dissipative solitons have been realized in mode-locked fiber lasers in the theoretical framework of the Ginzburg±Landau equation and have significantly improved the pulse energy and peak power levels of such lasers.It is interesting to explore whether dissipative solitons exist in optical parametric oscillators in the framework of three-wave coupling equations in order to substantially increase the performance of optical parametric oscillators.Here,we demonstrate a temporalfiltering dissipative soliton in a synchronously pumped optical parametric oscillator.The temporal-gain filtering of the pump pulse combined with strong cascading nonlinearity and dispersion in the optical parametric oscillator enables the generation of a broad spectrum with a nearly linear chirp;consequently,a significantly compressed pulse and high peak power can be realized after dechirping outside the cavity.Furthermore,we realized,for the first time,dissipative solitons in an optical system with a negative nonlinear phase shift and anomalous dispersion,extending the parameter region of dissipative solitons.The findings may open a new research block for dissipative solitons and provide new opportunities for mid-infrared ultrafast science.
文摘This research demonstrated quantitative methods of geospatial analysis applicable to carbon sequestration and storage in the conterminous United Sates. We identified national-scale NEP （net ecosystem production） changes for conversions to and from crop, and land in frequent conversion among forest, wetland, pasture and rangeland. The trend showed an increase in the margins of the Corn Belt states and coincided with land conversion from previous non-cropland to cropland in the United States. This research will not only improve the engineering understanding of carbon dioxide removal options involving the terrestrial biosphere, but will also inform decision-making in the carbon emission impacts. Therefore, it will provide a spatio-temporal reference for analyzing the national-level carbon exchange systems in the United States.
