Time series motifs are previously unknown,frequently occurring patterns in time series or approximately repeated subsequences that are very similar to each other.There are two issues in time series motifs discovery,th...Time series motifs are previously unknown,frequently occurring patterns in time series or approximately repeated subsequences that are very similar to each other.There are two issues in time series motifs discovery,the deficiency of the definition of K-motifs given by Lin et al.(2002) and the large computation time for extracting motifs.In this paper,we propose a relatively comprehensive definition of K-motifs to obtain more valuable motifs.Tominimize the computation time as much as possible,we extend the triangular inequality pruning method to avoid unnecessary operations and calculations,and propose an optimized matrix structure to produce the candidate motifs almost immediately.Results of two experiments on three time series datasets show that our motifs discovery algorithm is feasible and efficient.展开更多
针对结构纹理信息较复杂、破损尺度较大的图像修复问题,提出一种既能保持图像特征又能提高修复速度的参照四邻域裁剪样本的修复算法,将图像修复问题转化为最佳样本的检索过程。首先,提取图像结构信息,并对图像进行区域划分以缩小样本的...针对结构纹理信息较复杂、破损尺度较大的图像修复问题,提出一种既能保持图像特征又能提高修复速度的参照四邻域裁剪样本的修复算法,将图像修复问题转化为最佳样本的检索过程。首先,提取图像结构信息,并对图像进行区域划分以缩小样本的裁剪与检索范围;其次,为了改进离差平方和(SSD)方法对块的结构信息匹配的忽视,在像素块匹配计算中引入结构对称匹配约束,有效避免了误匹配,提高了图像块匹配精度及样本搜索效率;然后,通过引入结构因子和置信度,结合传统的优先权计算,得到突出结构作用的优先级公式;最后,利用目标块与四邻域块间的重叠区域计算四邻域参照优先级,并根据四邻域提供的可靠参照信息,依据改进的块匹配方法裁剪样本集并检索最佳样本块,直至所有目标块都检索匹配到最佳样本,完成修复。实验结果表明,该算法可以很好地解决纹理模糊和结构错位等问题,在提高图像修复速度的同时,所提算法修复效果的峰值信噪比(PSNR)比其他对比算法平均提高了0.5~1 d B,使得修复后的图像更好地满足视觉连通性,同时能高效地修复一般区域,具有更好的普适性。展开更多
According to the requirement of fast-growing forest pruning operation, the pruning robot was developed. The structure and control system of pruning robot were described, the work flow of pruning robot was expounded. T...According to the requirement of fast-growing forest pruning operation, the pruning robot was developed. The structure and control system of pruning robot were described, the work flow of pruning robot was expounded. The type and structure of the driving motor and the compression spring were decided with force-balance analysis. The tilt problem of pruning robot was resolved by ADAMS and Matlab co-sim- ulation, and the control scheme of climbing mechanism was determined. The experiment results of the prototype indicate that pruning robot can climb tree trunk smoothly at a speed of 20 mm/s and cross the raised trunk. The pruning saw which is driven by the adjustable speed motor can cut the branches of 30 mm. And the residual amount of branches is less than 5 mm. Pruning robot can meet the practical requirements of the fast-growing forest pruning work.展开更多
基金Project supported by the "Nuclear High Base" National Science and Technology Major Project (No.2010ZX01042-001-003)the National Basic Research Program (973) of China (No. 2007CB310804)the National Natural Science Foundation of China (No.61173061)
文摘Time series motifs are previously unknown,frequently occurring patterns in time series or approximately repeated subsequences that are very similar to each other.There are two issues in time series motifs discovery,the deficiency of the definition of K-motifs given by Lin et al.(2002) and the large computation time for extracting motifs.In this paper,we propose a relatively comprehensive definition of K-motifs to obtain more valuable motifs.Tominimize the computation time as much as possible,we extend the triangular inequality pruning method to avoid unnecessary operations and calculations,and propose an optimized matrix structure to produce the candidate motifs almost immediately.Results of two experiments on three time series datasets show that our motifs discovery algorithm is feasible and efficient.
文摘针对结构纹理信息较复杂、破损尺度较大的图像修复问题,提出一种既能保持图像特征又能提高修复速度的参照四邻域裁剪样本的修复算法,将图像修复问题转化为最佳样本的检索过程。首先,提取图像结构信息,并对图像进行区域划分以缩小样本的裁剪与检索范围;其次,为了改进离差平方和(SSD)方法对块的结构信息匹配的忽视,在像素块匹配计算中引入结构对称匹配约束,有效避免了误匹配,提高了图像块匹配精度及样本搜索效率;然后,通过引入结构因子和置信度,结合传统的优先权计算,得到突出结构作用的优先级公式;最后,利用目标块与四邻域块间的重叠区域计算四邻域参照优先级,并根据四邻域提供的可靠参照信息,依据改进的块匹配方法裁剪样本集并检索最佳样本块,直至所有目标块都检索匹配到最佳样本,完成修复。实验结果表明,该算法可以很好地解决纹理模糊和结构错位等问题,在提高图像修复速度的同时,所提算法修复效果的峰值信噪比(PSNR)比其他对比算法平均提高了0.5~1 d B,使得修复后的图像更好地满足视觉连通性,同时能高效地修复一般区域,具有更好的普适性。
基金supported by the Science and Technology Development Program of Shandong Province(Grant No.2013GNC11203)the National Natural Science Foundation of China(Grant Nos.51475278&3110146)the National Key Technology R&D Program(Grant No.2014BAD08B01-2)
文摘According to the requirement of fast-growing forest pruning operation, the pruning robot was developed. The structure and control system of pruning robot were described, the work flow of pruning robot was expounded. The type and structure of the driving motor and the compression spring were decided with force-balance analysis. The tilt problem of pruning robot was resolved by ADAMS and Matlab co-sim- ulation, and the control scheme of climbing mechanism was determined. The experiment results of the prototype indicate that pruning robot can climb tree trunk smoothly at a speed of 20 mm/s and cross the raised trunk. The pruning saw which is driven by the adjustable speed motor can cut the branches of 30 mm. And the residual amount of branches is less than 5 mm. Pruning robot can meet the practical requirements of the fast-growing forest pruning work.
