期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
Exploring geometry of genome space via Grassmann manifolds
1
作者 Xiaoguang Li Tao Zhou +2 位作者 xingdong feng Shing-Tung Yau Stephen S.-T.Yau 《The Innovation》 EI 2024年第5期92-99,91,共9页
It is important to understand the geometry of genome space in biology.After transforming genome sequences into frequency matrices of the chaos game representation(FCGR),we regard a genome sequence as a point in a suit... It is important to understand the geometry of genome space in biology.After transforming genome sequences into frequency matrices of the chaos game representation(FCGR),we regard a genome sequence as a point in a suitable Grassmann manifold by analyzing the column space of the corresponding FCGR.To assess the sequence similarity,we employ the generalized Grassmannian distance,an intrinsic geometric distance that differs from the traditional Euclidean distance used in the classical k-mer frequency-based methods.With this method,we constructed phylogenetic trees for various genome datasets,including influenza A virus hemagglutinin gene,Orthocoronavirinae genome,and SARS-CoV-2 complete genome sequences.Our comparative analysis with multiple sequence alignment and alignment-free methods for large-scale sequences revealed that our method,which employs the subspace distance between the column spaces of different FCGRs(FCGR-SD),outperformed its competitors in terms of both speed and accuracy.In addition,we used low-dimensional visualization of the SARS-CoV-2 genome sequences and spike protein nucleotide sequences with our methods,resulting in some intriguing findings.We not only propose a novel and efficient algorithm for comparing genome sequences but also demonstrate that genome data have some intrinsic manifold structures,providing a new geometric perspective for molecular biology studies. 展开更多
关键词 methods. MANIFOLD GEOMETRY
原文传递
无交叉多指标分位数回归模型中的估计与推断
2
作者 董宸 马舒洁 +1 位作者 朱利平 冯兴东 《中国科学:数学》 CSCD 北大核心 2021年第4期631-658,共28页
在过去的30年中分位数回归模型的研究已十分深入.然而在实际的应用场景中,由传统估计方法所得到的分位数回归估计量,经常会在不同分位数水平上出现互相交叉的现象,这给分位数回归模型的实际应用造成了解释和预测上的困难.为解决这个问题... 在过去的30年中分位数回归模型的研究已十分深入.然而在实际的应用场景中,由传统估计方法所得到的分位数回归估计量,经常会在不同分位数水平上出现互相交叉的现象,这给分位数回归模型的实际应用造成了解释和预测上的困难.为解决这个问题,本文提出一种带单调约束的半参数多指标分位数回归模型的研究框架.首先将半参数多指标分位数回归模型与充分降维模型相结合,并利用两者间的联系获得指标估计量的相合估计.之后使用张量积样条方法拟合半参数模型在单调约束条件下的非参数结构.通过数值模拟的方式比较所提方法与现有可行方案所得结果在平均预测误差上的差异,实验结果和实际案例的结果都验证了本文所提出模型的可行性. 展开更多
关键词 降维 线性规划 多指标模型 无交叉 分位数回归
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部