期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
基于DJI分步实现的联机空间距离查询处理 被引量:2
1
作者 肖予钦 张巨 +1 位作者 陈荦 景宁 《国防科技大学学报》 EI CAS CSCD 北大核心 2003年第6期5-9,共5页
综合考虑了查询处理时的计算费用和存储费用,提出了距离连接索引(Distance associatedJoinIn dices,DJI)的分步实现方法,以高效地支持联机空间距离查询。该方法采用分阶段计算DJI的策略,根据用户的查询条件动态地计算DJI的一部分以支持... 综合考虑了查询处理时的计算费用和存储费用,提出了距离连接索引(Distance associatedJoinIn dices,DJI)的分步实现方法,以高效地支持联机空间距离查询。该方法采用分阶段计算DJI的策略,根据用户的查询条件动态地计算DJI的一部分以支持查询。实验研究证明,与传统方法相比,DJI的分步实现方法在性能上具有较大优势。 展开更多
关键词 联机空间距离查询 距离连接索引 空间数据挖掘 空间数据库
下载PDF
Determination of genetic relationships between evergreen azalea cultivars in China using AFLP markers 被引量:7
2
作者 Hong ZHOU Jin LIAO +1 位作者 Yi-ping XIA Yuan-wen TENG 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2013年第4期299-308,共10页
Evergreen azaleas are among the most important ornamental shrubs in China.Today,there are probably over 300 cultivars preserved in different nurseries,but with little information available on the cultivar itself or re... Evergreen azaleas are among the most important ornamental shrubs in China.Today,there are probably over 300 cultivars preserved in different nurseries,but with little information available on the cultivar itself or relationships between cultivars.Amplified fragment length polymorphism(AFLP) markers were employed to determine the genetic relationships between evergreen azalea cultivars in China.One hundred and thirty genotypes collected from gardens and nurseries,including cultivars classified in the groups East,West,Hairy,and Summer,unknown cultivars,and close species,were analyzed using three primer pairs.A total of 408 polymorphic fragments were generated by AFLP reactions with an average of 136 fragments per primer pair.The average values of expected heterozygosity and Shannon's information index were 0.3395 and 0.5153,respectively.Genetic similarities were generated based on Dice coefficients,used to construct a neighbor joining tree,and bootstrapped for 100 replicates in Treecon V1.3b.Principal coordinate analysis(PCO) was performed based on Dice distances using NTSYS-pc software.The AFLP technique was useful for analyzing genetic diversity in evergreen azaleas.Cluster analysis revealed that cultivars in the West and Summer groups were quite distinct from other groups in the four-group classification system and that the East and Hairy groups should be redefined. 展开更多
关键词 Rhododendron spp. Tsutsusi Fluorescent label dice coefficient Principal coordinate analysis(PCO) Neighbor joining tree
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部