时空视频超分辨率(space-time video super-resolution,STVSR)通过时间和空间2个尺度提升视频的质量,从而实现在视频采集设备、传输或者存储有限的情况下依然能实时地呈现高分辨率和高帧率的视频,满足人们对超高清画质的追求。相比两阶...时空视频超分辨率(space-time video super-resolution,STVSR)通过时间和空间2个尺度提升视频的质量,从而实现在视频采集设备、传输或者存储有限的情况下依然能实时地呈现高分辨率和高帧率的视频,满足人们对超高清画质的追求。相比两阶段方法,一阶段方法实现的是特征层面而非像素层面的帧插值,其在推理速度和计算复杂度上都明显更胜一筹。一些现有的一阶段STVSR方法采用基于像素幻觉的特征插值,这幻化了像素,因此很难应对帧间快速运动物体的预测。为此,提出一种基于光流法的金字塔编码器-解码器网络来进行时间特征插值,实现快速的双向光流估计和更真实自然的纹理合成,在使得网络结构更高效的同时弥补了大运动对光流估计带来的不稳定性。另外,空间模块采用基于滑动窗口的局部传播和基于循环网络的双向传播来强化帧对齐,整个网络称为时间特征细化网络(temporal feature refinement netowrk,TFRnet)。为了进一步挖掘TFRnet的潜力,将空间超分辨率先于时间超分辨率(space-first),在几种广泛使用的数据基准和评估指标上的实验证明了所提出方法TFRnet-sf的出色性能,在总体峰值信噪比(peak signal to noise ratio,PSNR)和结构相似性(structural similarity,SSIM)提升的同时,插入中间帧的PSNR和SSIM也得到提升,在一定程度上缓和了插入的中间帧与原有帧之间PSNR和SSIM差距过大的问题。展开更多
Based on spatial interpolation rainfall of the ground gauge measurement,we proposed a method to comprehensively evaluate and compare the accuracy of satellite rainfall estimates (SREs) at three spatial scales:0.25...Based on spatial interpolation rainfall of the ground gauge measurement,we proposed a method to comprehensively evaluate and compare the accuracy of satellite rainfall estimates (SREs) at three spatial scales:0.25°×0.25° grid scale,sub-catchment scale and the whole basin scale.Using this method,we evaluated the accuracy of six high-resolution monthly SREs (TRMM 3B42 V6,3B42RT V6,CMORPH,GSMaP MWR+,GSMaP MVK+ and PERSIANN) and revealed the spatio-temporal variation of the SRE accuracy based on spatial interpolated rainfall from a dense network of 325 gauges during 2003-2009 over the Ganjiang River Basin in the Southeast China.The results showed that ground gauge-calibrated 3B42 had the highest accuracy with slight overestimation,whereas the other five uncalibrated SREs had severe underestimation.The accuracy of the six SREs in wet seasons was remarkably higher than that in the dry seasons.When the time scale was expanded,the accuracy of SRE,particularly 3B42,increased.Furthermore,the accuracy of SREs was relatively low in the western mountains and northern piedmont areas,while it was relatively high in the central and southeastern hills and basins of the Ganjiang River Basin.When the space scale was expanded,the accuracy of the six SREs gradually increased.This study provided an example for of SRE accuracy validation in other regions,and a direct basis for further study of SRE-based hydrological process.展开更多
In this paper, two new interpolation algorithms lot CNC machining along curve^l tom pathes are proposed： a time-optimal interpolation algorithm under chord error, feedrate, and tangential acceleration bounds, and a g...In this paper, two new interpolation algorithms lot CNC machining along curve^l tom pathes are proposed： a time-optimal interpolation algorithm under chord error, feedrate, and tangential acceleration bounds, and a greedy interpolation algorithm under the chord error and tangential jerk bounds. The key idea is to reduce the chord error bound to a centripetal acceleration bound which leads to a velocity limit curve, called the chord error velocity limit curve. Then, the velocity planning is to find the proper velocity curve governed by the acceleration or jerk bounds ＇~under＂ the chord error velocity limit curve. For two types of simple tool pathes, explicit formulas for the velocity curve are given and the methods are implemented in commercial CNC controllers.展开更多
In this paper,we apply function parameters,introduced by Persson,to real interpolation of Lorentz martingale spaces.Some new interpolation theorems concerning Lorentz martingale spaces are formulated.The results that ...In this paper,we apply function parameters,introduced by Persson,to real interpolation of Lorentz martingale spaces.Some new interpolation theorems concerning Lorentz martingale spaces are formulated.The results that we obtain generalize some fundamental interpolation theorems in classical martingale Hp theory.展开更多
In this paper, we study a kind of nonlinear model of adiabatic evolution in quantum search problem. As will be seen here, for this problem, there always exists a possibility that this nonlinear model can successfully ...In this paper, we study a kind of nonlinear model of adiabatic evolution in quantum search problem. As will be seen here, for this problem, there always exists a possibility that this nonlinear model can successfully solve the problem, while the linear model can not. Also in the same setting, when the overlap between the initial state and the final stare is sufficiently large, a simple linear adiabatic evolution can achieve O(1) time efficiency, but infinite time complexity for the nonlinear model of adiabatic evolution is needed. This tells us, it is not always a wise choice to use nonlinear interpolations in adiabatic algorithms. Sometimes, simple linear adiabatic evolutions may be sufficient for using.展开更多
文摘时空视频超分辨率(space-time video super-resolution,STVSR)通过时间和空间2个尺度提升视频的质量,从而实现在视频采集设备、传输或者存储有限的情况下依然能实时地呈现高分辨率和高帧率的视频,满足人们对超高清画质的追求。相比两阶段方法,一阶段方法实现的是特征层面而非像素层面的帧插值,其在推理速度和计算复杂度上都明显更胜一筹。一些现有的一阶段STVSR方法采用基于像素幻觉的特征插值,这幻化了像素,因此很难应对帧间快速运动物体的预测。为此,提出一种基于光流法的金字塔编码器-解码器网络来进行时间特征插值,实现快速的双向光流估计和更真实自然的纹理合成,在使得网络结构更高效的同时弥补了大运动对光流估计带来的不稳定性。另外,空间模块采用基于滑动窗口的局部传播和基于循环网络的双向传播来强化帧对齐,整个网络称为时间特征细化网络(temporal feature refinement netowrk,TFRnet)。为了进一步挖掘TFRnet的潜力,将空间超分辨率先于时间超分辨率(space-first),在几种广泛使用的数据基准和评估指标上的实验证明了所提出方法TFRnet-sf的出色性能,在总体峰值信噪比(peak signal to noise ratio,PSNR)和结构相似性(structural similarity,SSIM)提升的同时,插入中间帧的PSNR和SSIM也得到提升,在一定程度上缓和了插入的中间帧与原有帧之间PSNR和SSIM差距过大的问题。
基金supported by the National Natural Science Foundation of China (Grant No. 51109136)the Commonweal Science Research Project of Ministry of Water Resources of China (Grant Nos. 201001002,201101004)the Science and Technology Development Fund,Ministry of Water Resources of China (Grant No. TG1109)
文摘Based on spatial interpolation rainfall of the ground gauge measurement,we proposed a method to comprehensively evaluate and compare the accuracy of satellite rainfall estimates (SREs) at three spatial scales:0.25°×0.25° grid scale,sub-catchment scale and the whole basin scale.Using this method,we evaluated the accuracy of six high-resolution monthly SREs (TRMM 3B42 V6,3B42RT V6,CMORPH,GSMaP MWR+,GSMaP MVK+ and PERSIANN) and revealed the spatio-temporal variation of the SRE accuracy based on spatial interpolated rainfall from a dense network of 325 gauges during 2003-2009 over the Ganjiang River Basin in the Southeast China.The results showed that ground gauge-calibrated 3B42 had the highest accuracy with slight overestimation,whereas the other five uncalibrated SREs had severe underestimation.The accuracy of the six SREs in wet seasons was remarkably higher than that in the dry seasons.When the time scale was expanded,the accuracy of SRE,particularly 3B42,increased.Furthermore,the accuracy of SREs was relatively low in the western mountains and northern piedmont areas,while it was relatively high in the central and southeastern hills and basins of the Ganjiang River Basin.When the space scale was expanded,the accuracy of the six SREs gradually increased.This study provided an example for of SRE accuracy validation in other regions,and a direct basis for further study of SRE-based hydrological process.
基金supported by a National Key Basic Research Project of China under Grant No.2011CB302400the National Natural Science Foundation of China under Grant No.60821002
文摘In this paper, two new interpolation algorithms lot CNC machining along curve^l tom pathes are proposed： a time-optimal interpolation algorithm under chord error, feedrate, and tangential acceleration bounds, and a greedy interpolation algorithm under the chord error and tangential jerk bounds. The key idea is to reduce the chord error bound to a centripetal acceleration bound which leads to a velocity limit curve, called the chord error velocity limit curve. Then, the velocity planning is to find the proper velocity curve governed by the acceleration or jerk bounds ＇~under＂ the chord error velocity limit curve. For two types of simple tool pathes, explicit formulas for the velocity curve are given and the methods are implemented in commercial CNC controllers.
基金supported by National Natural Science Foundation of China(Grant No. 11171015)
文摘In this paper,we apply function parameters,introduced by Persson,to real interpolation of Lorentz martingale spaces.Some new interpolation theorems concerning Lorentz martingale spaces are formulated.The results that we obtain generalize some fundamental interpolation theorems in classical martingale Hp theory.
基金Supported by the National Natural Science Foundation of China under Grant Nos.61402188 and 61173050the support from the China Postdoctoral Science Foundation under Grant No.2014M552041
文摘In this paper, we study a kind of nonlinear model of adiabatic evolution in quantum search problem. As will be seen here, for this problem, there always exists a possibility that this nonlinear model can successfully solve the problem, while the linear model can not. Also in the same setting, when the overlap between the initial state and the final stare is sufficiently large, a simple linear adiabatic evolution can achieve O(1) time efficiency, but infinite time complexity for the nonlinear model of adiabatic evolution is needed. This tells us, it is not always a wise choice to use nonlinear interpolations in adiabatic algorithms. Sometimes, simple linear adiabatic evolutions may be sufficient for using.
