基于本体语义的定题爬虫

定题爬虫能迅速获取网络上特定主题的大量信息,对专业搜索引擎及数据挖掘应用都具有重大价值. 针对 目前通用的基于关键词主题过滤策略的不足,在概念聚集思想启发下,提出了基于本体语义的主题过滤策略. 同 时根据网页具有不同位置不同信息重要性的特点,提出了改进的加权特征项权值计算公式,实现基于语义的网页 实时过滤. 为进一步提高爬虫的工作效率提出链接相关度预测算法. 对比实验表明此策略具有可行性.厦门大学985 二期信息创新平台资助项目(00002X07204

RAPD Studies of Parents of Three-Line Hybrid Rice

选用9个随机引物对31份杂交水稻亲本材料进行了rAPd分析，共检测到60条多态性带。聚类分析结果表明，所有供试材料可以被明确地区分。在9个随机引物中，有8个具有较高的多态性检测能力。以这8个引物为基础，选用任两个引物即可在任一对材料中检测出多态性的频率在9613%以上，而选用任3个引物则该频率在9921%以上。这显示了运用rAPd鉴定稻种具有简便、灵敏、高效的优点，在鉴定杂交稻种的实践中有着良好的应用前景。Seven rice male sterile lines, 12 maintainer lines and 12 restorer lines were analyzed by RAPD with 9 primers Altogether, 118 fragments were generated, of which 60 detected polymorphisms among rice lines tested.Cluster analysis showed that all lines could be uniquely distinguished by at least one RAPD marker.Eight of nine primers can detect high polymorphism.The frequencies of polymorphism in any pairs of lines would be higher than 96.13% when any two of the 8 primers were used.If any three of the 8 primers were used, the frequencies would be higher than 99.21%.The eight primers were therefore recommended as candidates for the identification of hybrid rice seeds.国家水稻基因组计划;农业部重点项

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies