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禾本科植物内生真菌研究22:Epichloe festucae E2368基因组中非核糖体肽合成酶编码基因的挖掘与分析
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作者 纪燕玲 韩魁 +2 位作者 茅冬梅 陈永敢 王志伟 《南京农业大学学报》 CAS CSCD 北大核心 2024年第6期1097-1104,共8页
[目的]Epichloe内生真菌能够产生抵御牲畜和害虫啃食的生物碱,其中部分生物碱由非核糖体肽合成酶(non-ribosomal peptide synthetase,NRPS)合成。本研究旨在分析E.festucae基因组内的NRPS编码基因,并预测其功能。[方法]以E.festucae E2... [目的]Epichloe内生真菌能够产生抵御牲畜和害虫啃食的生物碱,其中部分生物碱由非核糖体肽合成酶(non-ribosomal peptide synthetase,NRPS)合成。本研究旨在分析E.festucae基因组内的NRPS编码基因,并预测其功能。[方法]以E.festucae E2368菌株基因组数据为对象,综合运用HMMER和全局比对等分析方法以及ClustScan、PKS/NRPS Analysis和NCBI等数据库进行信息比对。[结果]E2368基因组中含有至少19个候选NRPS基因,其中11个未在Epichloe内生真菌中报道。序列比对结果表明候选基因均为子囊菌中已报道的序列,但其中8个基因的功能未知;E2368基因组中存在环孢菌素合成酶基因扩增现象。构建候选NRPS基因所有A结构域氨基酸序列发育树,发现不同NRPS基因的A结构域会聚到同一分枝,而相同NRPS基因的A结构域则分散于不同分枝,说明采用简并引物扩增NRPS基因存在一定的局限性。[结论]对E2368基因组中NRPS基因的挖掘,将有助于解析NRPS基因的多样性,促进对新的天然产物的发现和生物合成途径的认识。 展开更多
关键词 NRPS数据库 基因挖掘 生物碱 类似度分析 禾本科植物内生真菌
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虚拟化网络中的异常大数据剔除算法仿真
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作者 李军华 丁宪成 《计算机仿真》 北大核心 2021年第10期410-413,475,共5页
网络中的冗余数据过多会导致网络运行速度降低,为此提出虚拟化网络中的异常大数据剔除算法。分析虚拟化网络中异常大数据的类似度,使用决策树模型分解提取异常大数据数值属性特征以及分类属性特征,再利用关联规则分析法融合模糊数据,计... 网络中的冗余数据过多会导致网络运行速度降低,为此提出虚拟化网络中的异常大数据剔除算法。分析虚拟化网络中异常大数据的类似度,使用决策树模型分解提取异常大数据数值属性特征以及分类属性特征,再利用关联规则分析法融合模糊数据,计算出属性值自相关的特征分块函数,即可挖掘出异常数据。利用测量数据间的接近度验证虚拟化网络数据,把节点数据作为一个集合,通过模糊集合间的接近度,设定冗余数据的判定门限值,将滤除数据带入粒子群优化以及支持向量机内构建数据库,并对所有粒子位置更新,采用最优粒子构建检测模型,同时调整异常特征剔除窗口参数,实现异常大数据剔除。仿真结果证明,所提方法能够全面剔除数据,且误剔除率低。 展开更多
关键词 虚拟化网络 异常大数据 数据剔除 类似度分析 冗余过滤
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Clustering analysis algorithm for security supervising data based on semantic description in coal mines 被引量:1
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作者 孟凡荣 周勇 夏士雄 《Journal of Southeast University(English Edition)》 EI CAS 2008年第3期354-357,共4页
In order to mine production and security information from security supervising data and to ensure security and safety involved in production and decision-making,a clustering analysis algorithm for security supervising... In order to mine production and security information from security supervising data and to ensure security and safety involved in production and decision-making,a clustering analysis algorithm for security supervising data based on a semantic description in coal mines is studied.First,the semantic and numerical-based hybrid description method of security supervising data in coal mines is described.Secondly,the similarity measurement method of semantic and numerical data are separately given and a weight-based hybrid similarity measurement method for the security supervising data based on a semantic description in coal mines is presented.Thirdly,taking the hybrid similarity measurement method as the distance criteria and using a grid methodology for reference,an improved CURE clustering algorithm based on the grid is presented.Finally,the simulation results of a security supervising data set in coal mines validate the efficiency of the algorithm. 展开更多
关键词 semantic description clustering analysis algorithm similarity measurement
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Vari-gram language model based on word clustering
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作者 袁里驰 《Journal of Central South University》 SCIE EI CAS 2012年第4期1057-1062,共6页
Category-based statistic language model is an important method to solve the problem of sparse data.But there are two bottlenecks:1) The problem of word clustering.It is hard to find a suitable clustering method with g... Category-based statistic language model is an important method to solve the problem of sparse data.But there are two bottlenecks:1) The problem of word clustering.It is hard to find a suitable clustering method with good performance and less computation.2) Class-based method always loses the prediction ability to adapt the text in different domains.In order to solve above problems,a definition of word similarity by utilizing mutual information was presented.Based on word similarity,the definition of word set similarity was given.Experiments show that word clustering algorithm based on similarity is better than conventional greedy clustering method in speed and performance,and the perplexity is reduced from 283 to 218.At the same time,an absolute weighted difference method was presented and was used to construct vari-gram language model which has good prediction ability.The perplexity of vari-gram model is reduced from 234.65 to 219.14 on Chinese corpora,and is reduced from 195.56 to 184.25 on English corpora compared with category-based model. 展开更多
关键词 word similarity word clustering statistical language model vari-gram language model
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