雷暴追踪矢量的准确性是决定短时临近降水外推预报效果的关键。以TREC(Tracking Radar Echoes by Correlation)为代表的区域追踪和以TITAN(Thunderstorm Identifiation, Tracking, Analysis, and Nowcasting)为代表的单体追踪是追踪雷...雷暴追踪矢量的准确性是决定短时临近降水外推预报效果的关键。以TREC(Tracking Radar Echoes by Correlation)为代表的区域追踪和以TITAN(Thunderstorm Identifiation, Tracking, Analysis, and Nowcasting)为代表的单体追踪是追踪雷暴移动矢量的两种典型方法。TREC基于追踪格点雷达回波数据得到,能较好体现层状云降水和对流云降水系统的区域总体移动趋势;TITAN可以识别、分析雷暴的二维和三维属性,自动跟踪雷暴的移动速度和方向,形成雷暴单体移动矢量,能够更好地刻画小尺度雷暴单体的移动速度和方向。将TREC和TITAN两种移动矢量进行融合,生成新的外推移动矢量,既保留了TREC方法在刻画大尺度雷暴总体移动趋势信息方面的特长,又能充分发挥TITAN方法在刻画小尺度雷暴运动细节信息上的优势。融合试验表明,采用TREC和TITAN两种降水移动矢量融合的新技术,可以一定程度改进降水外推移动矢量场估计的准确度,提升降水落区和强度外推预报的准确度,对改善北京地区降水临近预报水平具有一定正效果。展开更多
Starting from the basic equation of elastic mechanics, without any additional hypotheses of displacement or stress model, just introducing state space and state equation, the model of rock strata movement as complex l...Starting from the basic equation of elastic mechanics, without any additional hypotheses of displacement or stress model, just introducing state space and state equation, the model of rock strata movement as complex laminated plates is presented. In addition, using displacement as a basic unknown quantity, the accurate analytical series solution for the problem of strata movement induced by extraction of horizontal seam is worked out when crosswise isotropic elastic layers are in sliding contact condition. A new approach is put forward to solve the complicated system of mining subsidence.展开更多
Extraction of moving objects is an important and fundamental research topic for many video applications. This paper addresses an unsupervised spatio-temporal segmentation scheme to extract moving objects from video se...Extraction of moving objects is an important and fundamental research topic for many video applications. This paper addresses an unsupervised spatio-temporal segmentation scheme to extract moving objects from video sequences.The temporal segmentation localizes moving objects by comparing the motion vector of each block in each frame with the corresponding global motion vector estimated by an outlier rejection(OR) based method.Furthermore,the temporal compensation utilizing the temporal coherence of moving objects is considered in the temporal segmentation to solve the temporarily stopping problem.The detected moving regions usually have discontinuous boundaries and some holes.These regions are then compensated in the spatial domain. In the spatial segmentation,the watershed algorithm considering the global information improves the accuracy of segmentation in the spatial domain.The modified mean filter is presented to suppress some minima.By using a fusion module,moving objects are extracted.Experiments on various sequences have successfully demonstrated the validity of the proposed scheme.展开更多
文摘雷暴追踪矢量的准确性是决定短时临近降水外推预报效果的关键。以TREC(Tracking Radar Echoes by Correlation)为代表的区域追踪和以TITAN(Thunderstorm Identifiation, Tracking, Analysis, and Nowcasting)为代表的单体追踪是追踪雷暴移动矢量的两种典型方法。TREC基于追踪格点雷达回波数据得到,能较好体现层状云降水和对流云降水系统的区域总体移动趋势;TITAN可以识别、分析雷暴的二维和三维属性,自动跟踪雷暴的移动速度和方向,形成雷暴单体移动矢量,能够更好地刻画小尺度雷暴单体的移动速度和方向。将TREC和TITAN两种移动矢量进行融合,生成新的外推移动矢量,既保留了TREC方法在刻画大尺度雷暴总体移动趋势信息方面的特长,又能充分发挥TITAN方法在刻画小尺度雷暴运动细节信息上的优势。融合试验表明,采用TREC和TITAN两种降水移动矢量融合的新技术,可以一定程度改进降水外推移动矢量场估计的准确度,提升降水落区和强度外推预报的准确度,对改善北京地区降水临近预报水平具有一定正效果。
文摘Starting from the basic equation of elastic mechanics, without any additional hypotheses of displacement or stress model, just introducing state space and state equation, the model of rock strata movement as complex laminated plates is presented. In addition, using displacement as a basic unknown quantity, the accurate analytical series solution for the problem of strata movement induced by extraction of horizontal seam is worked out when crosswise isotropic elastic layers are in sliding contact condition. A new approach is put forward to solve the complicated system of mining subsidence.
基金the National Natural Science Foundationof China(No.60502034)
文摘Extraction of moving objects is an important and fundamental research topic for many video applications. This paper addresses an unsupervised spatio-temporal segmentation scheme to extract moving objects from video sequences.The temporal segmentation localizes moving objects by comparing the motion vector of each block in each frame with the corresponding global motion vector estimated by an outlier rejection(OR) based method.Furthermore,the temporal compensation utilizing the temporal coherence of moving objects is considered in the temporal segmentation to solve the temporarily stopping problem.The detected moving regions usually have discontinuous boundaries and some holes.These regions are then compensated in the spatial domain. In the spatial segmentation,the watershed algorithm considering the global information improves the accuracy of segmentation in the spatial domain.The modified mean filter is presented to suppress some minima.By using a fusion module,moving objects are extracted.Experiments on various sequences have successfully demonstrated the validity of the proposed scheme.
