期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
逆序树在求解一维数组最长升序序列问题中的应用 被引量:1
1
作者 刘芳 《计算机时代》 2013年第3期37-38,41,共3页
针对一维数组中求最长升序序列问题,在研究树形结构和分析任务需求的基础上,提出采用区别于传统树的逆序树结构进行计算,采用深度优先算法策略查找路径。逆序树采用子节点指向父节点的节点逆序指向方式,在建树过程中不用为每个节点考虑... 针对一维数组中求最长升序序列问题,在研究树形结构和分析任务需求的基础上,提出采用区别于传统树的逆序树结构进行计算,采用深度优先算法策略查找路径。逆序树采用子节点指向父节点的节点逆序指向方式,在建树过程中不用为每个节点考虑子节点的数量,克服了不可预见的存储分配和节点指向问题,能有效地找出全部升序路径,最终找出一维数组中全局最长的升序序列。在此基础上实现的Java程序验证了逆序树结构的有效性。 展开更多
关键词 逆序 传统树 节点 深度优先 最长升序序列
下载PDF
基于CURE聚类算法的静态R树构建方法 被引量:6
2
作者 李松 崔环宇 +1 位作者 张丽平 经海东 《计算机科学》 CSCD 北大核心 2015年第10期193-197,共5页
R树索引结构在空间对象查询和复杂空间关系查询方面具有重要作用。传统空间索引结构R树是动态生成的,树的结构是根据连续插入算法实现的,通过分裂子节点直至生成R树的根节点。动态生成算法会导致R树节点最小外包矩形之间的大量重叠,影... R树索引结构在空间对象查询和复杂空间关系查询方面具有重要作用。传统空间索引结构R树是动态生成的,树的结构是根据连续插入算法实现的,通过分裂子节点直至生成R树的根节点。动态生成算法会导致R树节点最小外包矩形之间的大量重叠,影响空间查询效率,且空间利用率不高。为了弥补动态生成R树的不足,提出了基于CURE算法的静态R树生成方法,给出CU_RHbuilt建树算法,该算法不仅能有效地处理海量数据,识别任何形状的簇,减少矩形重叠度,而且采用划分技术可较大程度地减小计算代价,空间利用率较高。进一步提出了基于CURE算法的R树节点分裂方法。理论研究与实验表明,所提方法具有较高的查询效率。 展开更多
关键词 传统R 静态R CURE算法 海量数据
下载PDF
基于CUK-MEANS算法的R树构建
3
作者 崔环宇 李松 +1 位作者 张丽平 经海东 《小型微型计算机系统》 CSCD 北大核心 2016年第2期264-268,共5页
针对K-means方法的不足,提出CUK-MEANS算法,用以解决K-MEANS方法在初始值选择上的不足和对噪声点敏感的问题.传统R树索引是动态生成的,通过节点的连续插入和分裂实现整个索引的构建,这种方法会造成大量的外包矩形重叠,从而导致索引效率... 针对K-means方法的不足,提出CUK-MEANS算法,用以解决K-MEANS方法在初始值选择上的不足和对噪声点敏感的问题.传统R树索引是动态生成的,通过节点的连续插入和分裂实现整个索引的构建,这种方法会造成大量的外包矩形重叠,从而导致索引效率不高.基于CUK-MEANS算法本文进一步提出了CKR-R()算法,利用聚类技术对数据进行预处理,减少节点之间的重叠度,提高了R树的索引效率,并且采用收缩因子使节点内数据更加紧凑,提高节点的空间利用率.理论研究和实验表明所提算法具有较高的查询效率. 展开更多
关键词 K-MEANS算法 传统R 索引效率 空间利用率
下载PDF
超高压交直流输电线路树障隐患测量方案探析
4
作者 薛鹏程 刘成 孙阔腾 《进展》 2020年第19期49-51,共3页
本文通过对比传统树障测量、可见光树障测量、激光雷达树障测量和单线贴线自主飞行树障测量来了解近年来针对树障测量方案的变化,探讨分析了可见光树障测量、激光雷达树障测量、单线贴线自主飞行树障测量三种方案,介绍了三种方案的测量... 本文通过对比传统树障测量、可见光树障测量、激光雷达树障测量和单线贴线自主飞行树障测量来了解近年来针对树障测量方案的变化,探讨分析了可见光树障测量、激光雷达树障测量、单线贴线自主飞行树障测量三种方案,介绍了三种方案的测量方法。 展开更多
关键词 传统树障测量 可见光障测量 激光雷达障测量 单线贴线自主飞行障测量
下载PDF
CONSTRAINED VITERBI ALGORITHM AND ITS APPLICATION TO ERROR RESILIENT TRANSMISSION OF SPIHT CODED IMAGES 被引量:1
5
作者 周霆 许明 +1 位作者 陈东侠 余轮 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2008年第2期155-159,共5页
To overcome some drawbacks of Viterbi algorithm (VA), such as exponential growing complexity of decoding, and its poor performance under bad channel conditions, some available known information must be used as cons... To overcome some drawbacks of Viterbi algorithm (VA), such as exponential growing complexity of decoding, and its poor performance under bad channel conditions, some available known information must be used as constrained condition and apriori knowledge for decoding. A new constrained VA is proposed by adding con- straint bits directly for conventional codec. Compared with the conventional VA, under the bad channel condi- tion, the proposed scheme can improve the peak signal to noise ratio (PSNR) of the decoding image 2--10 dB by changing the number of constrained bits. Experimental results show that it is an efficient error-controlling way for the transmission of set partitioning in hierarchical trees (SPIHT) coded image. 展开更多
关键词 Viterbi algorithm(VA) image communication systems constrained Viterbi algorithm(C-VA) set partitioning in hierachical trees(SPIHT)
下载PDF
Assessing the Efficiency of Sponge and Traditional Methods of Pollination in Date Palm
6
作者 Abdallah Ben Abdallah Nabeel Ali Al-Wusaibai Youssef Al-Fehaid 《Journal of Agricultural Science and Technology(B)》 2014年第4期267-271,共5页
In date palm Phoenix dactylifera L. male (pollen bearing) and female (fruit bearing) inflorescences are on separate palms. To ensure good fertilization and better yield, artificial pollination is carried out in da... In date palm Phoenix dactylifera L. male (pollen bearing) and female (fruit bearing) inflorescences are on separate palms. To ensure good fertilization and better yield, artificial pollination is carried out in date plantations, where pollen harvested from male flowers are used for artificial pollination which is usually done manually. Often, the availability of male flowers becomes scarce due to the high demand to take up pollination during the short period of time when the female flowers are receptive. We assessed the comparative efficiency of using pollen to manually pollinate female date palm flowers in the field using sponge pieces charged with harvested pollen as compared to the traditional practice of the farmers using male inflorescences. Results revealed that fruit set (%), fructification (%), yield per bunch (kg) besides fruit weight, length and breadth were statistically similar in the two pollination methods evaluated. The sponge method of manual pollination can therefore serve as a viable alternative to the traditional method of pollination with the possibility of using stored pollen especially where male palms are scarce and pollen is difficult to obtain. 展开更多
关键词 Date palm manual pollination sponge technique fruit set fructification.
下载PDF
Effect of Fertilization in Organic Nursery for Later Growth and Fruiting of Apple Trees in the Orchard 被引量:1
7
作者 Zygmunt Stanislw Grzyb Wojciech Piotrowski Lidia Sas Paszt 《Journal of Life Sciences》 2015年第4期159-165,共7页
There is a deficiency of nurseries in the world producing fruit trees using the organic material management. However, such material has been produced since 2009 at the Research Institute of Horticulture in Skierniewic... There is a deficiency of nurseries in the world producing fruit trees using the organic material management. However, such material has been produced since 2009 at the Research Institute of Horticulture in Skierniewice. To stimulate plant growth, various biopreparations were applied in an organic nursery. Apple trees ('Topaz'/M26) obtained from the organic nursery were used to establish an orchard in 2011. One of the combinations in the orchard consisted of trees produced in a conventional nursery. Trees whose maidens had not been fertilized at all in the organic nursery served as the control. The study was conducted for four years (2011-2014). The least vigorously growing trees were the control trees and those that had been treated in the nursery with the preparation Tytanit, and the most vigorously--those that had been treated there with manure and the biopreparations Micosat, Humus Active + Aktywit PM, and BF Quality and BF Amin. Trees whose maidens had been produced by the conventional method did not differ, in terms of growth vigour, from those treated with the biopreparations Humus UP or Vinassa. The highest cumulative fruit yields from the four-year-old trees were obtained in the combinations where the maidens had been treated in the nursery with the biopreparations BF Amin and BF Quality. The type of fertilization applied to maiden trees in the nursery had no significant effect on mean fruit weight, but it influenced the distribution of fruit in size classes. 展开更多
关键词 'Topaz'/M26 BIOPRODUCTS ROOTSTOCK yield fruit size and weight.
下载PDF
基于边界约束RRT的未知环境探索方法 被引量:7
8
作者 吕伟新 赵立军 +1 位作者 王珂 李志鹏 《华中科技大学学报(自然科学版)》 EI CAS CSCD 北大核心 2011年第S2期366-369,共4页
针对移动机器人未知环境探索有效性问题,对传统快速扩展随机树(RRT)算法进行改进,降低了探索盲目性.提出一种未知环境探索的路径规划方法,该方法借助环境局部知识,对目标进行包围式搜索,同时制定了环境动态因素分割策略,完成环境的全过... 针对移动机器人未知环境探索有效性问题,对传统快速扩展随机树(RRT)算法进行改进,降低了探索盲目性.提出一种未知环境探索的路径规划方法,该方法借助环境局部知识,对目标进行包围式搜索,同时制定了环境动态因素分割策略,完成环境的全过程探索.仿真验证表明:该方法提高了环境探索的有效性和主动性. 展开更多
关键词 机器人 路径规划 导航 传统快速扩展随机(RRT) 环境探索
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部