检索结果-南通市图书馆

维普期刊数据库博看期刊

严格双对角占优矩阵的Schur补的双对角占优度及其应用

在线全文

学校读者我要写书评

暂无评论

工程数学学报 2024年第4期41卷 595-608页

作者：王金辉李耀堂云南大学数学与统计学院昆明650500

矩阵Schur补是矩阵理论及其应用中的一个重要内容,具有广泛的应用背景。严格双对角占优矩阵是一类十分重要的特殊矩阵,流体力学的计算、材料模拟与设计、电磁场计算等领域与其有着密不可分的联系。对严格双对角占优矩阵的研究主要集中... 详细信息

矩阵Schur补是矩阵理论及其应用中的一个重要内容,具有广泛的应用背景。严格双对角占优矩阵是一类十分重要的特殊矩阵,流体力学的计算、材料模拟与设计、电磁场计算等领域与其有着密不可分的联系。对严格双对角占优矩阵的研究主要集中在两个方面:严格双对角占优矩阵的Schur补的特征值定位;严格双对角占优矩阵Schur补的逆的无穷范数估计。首先,给出了严格双对角占优矩阵的Schur补的双对角占优度的新下界估计式;然后,利用所给估计式获得了严格双对角占优矩阵Schur补新的特征值包含集和严格对角占优矩阵Schur补的逆的无穷范数的新上界。数值例子表明所获结果改进了一些现有结果。

关键词：双对角占优矩阵双对角占优度 Schur补特征值

The optimal sex ratio in cooperatively breeding populations

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2014年第35期59卷 5074-5079页

作者： Yaqiang Wang yaotang li Ruiwu Wang School of Mathematics and Statistics Yunnan University State Key Laboratory of Genetic Resources and Evolution EcologyConservationand Environment CenterKunming Institute of ZoologyChinese Academy of Sciences

In some cooperatively breeding species,elder siblings remain within their home ranges to assist their parents in raising their younger siblings by providing protection or *** attempts to model the population sex ratios of such species have assumed that helping is cost-free and only involves benefits to parents,resulting in offspring sex ratio biases towards the helping ***,parents may also incur costs in maintaining *** incorporated costs and benefits of helping to predict the sex ratio of offspring in a theoretical *** model showed that the evolutionary stable strategy(ESS)sex ratio strongly depends on three parameters:(1) the average number of helpers per female;(2) the benefits that a helper brings to its mother's offspring production(MOP);and(3) the cost-benefit ratio of *** one sex of elder siblings provides help,the ESS sex ratio is biased towards the helping sex if MOP costs are less than the benefits,(i.e.,the cost-benefit ratio \1).However,the ESS sex ratio becomes biased towards the non-helping sex if MOP costs exceed the benefits(i.e.,the cost-benefit ratio [1).Additionally,our model shows that the ESS sex ratio becomes biased in favor of the more helpful sex when both male and female elder siblings provide *** results explain why sex ratios may become biased towardsthe helping sex,as well as the non-helping sex,in some species.

关键词：性别比例育种群体成本效益协作进化稳定策略模型显示 ESS MOP

Criterions for identifying H-tensors

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2016年第3期11卷 661-678页

作者： Ruijuan ZHAO Lei GAO Qilong liU yaotang li School of Information Engineering Lanzhou University of Finance and Economics Lanzhou 730020 China School of Mathematics and Statistics Yunnan University Kunming 650091 China Institute of Mathematics and Information Science Baoji University of Arts and Sciences Baoji 721013 China

Some new criteria for identifying H-tensors are obtained. As applications, some sufficient conditions of the positive definiteness for an even- order real symmetric tensor are given, as well as a new eigenvalue inclusion region for tensors is established. It is proved that the new eigenvalue inclusion region is tighter than that of Y. Yang and Q. Yang [SIAM J. Matrix Anal. Appl., 2010, 31： 2517-2530]. Numerical examples are reported to demonstrate the corresponding results.

关键词： H-Tensor real symmetric tensor positive definite eigenvalueinclusion set

复区间矩阵的Gerschgorin圆盘定理及正则性条件

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

数学理论与应用 2024年第1期44卷 109-121页

作者：成龙夏丹丹李耀堂重庆对外经贸学院数学与计算机学院重庆401520 云南大学数学与统计学院昆明650091

本文将矩阵特征值的Gerschgorin圆盘定理推广到复区间矩阵,给出复区间矩阵特征值的Gerschgorin圆盘区域,并证明所给复区间矩阵特征值的Gerschgorin圆盘区域包含于已有的复区间矩阵特征值的Gerschgorin方盘区域.最后,应用复区间矩阵特征... 详细信息

本文将矩阵特征值的Gerschgorin圆盘定理推广到复区间矩阵,给出复区间矩阵特征值的Gerschgorin圆盘区域,并证明所给复区间矩阵特征值的Gerschgorin圆盘区域包含于已有的复区间矩阵特征值的Gerschgorin方盘区域.最后,应用复区间矩阵特征值的Gerschgorin圆盘定理得到复区间矩阵正则的两个新的充分条件.

关键词：复区间矩阵特征值 Gerschgorin圆盘定理正则性

Two-dimensional magnetic resonance neurography in neurotmesis of the left sciatic nerve A case report

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2010年第14期5卷 1113-1116页

作者： Zhongjun Hou Xiaojun Yu Xi li yaotang Chen Department of Gamma Knife Second Affiliated Hospital Guangzhou Medical University Guangzhou 510260 Guangdong Province China

Magnetic resonance neurography （MRN） is used to determine traumatic changes within nervous trunks. A 21-year-old male was treated for neurotmesis of the left sciatic nerve. At 41 days after micro-neurosurgery, two-dimensional MRN （2-D MRN） was performed with plain and contrast scans in the left injured sciatic nerve. More than 2 years after trauma, 2-D MRN images were collected to re-examine the left sciatic nerve. Results from the first 2-D MRN examination revealed a swollen left sciatic nerve. Furthermore, TlWl revealed a local nodule with slightly high intensity, and T2WI revealed hyperintensity. The nodule was significantly enhanced. Upon 2-D MRN re-examination more than 2 years after injury, the injured left sciatic nerve trunk was thinner, and the nodule margin in the left sciatic trunk was clearer. The supero-inferior diameter was enlarged by 2 mm compared with previous films. The degree of enhancement became weaker in the nodule. 2-D MRN revealed continuity, traumatic neuroma, and atrophy of the injured sciatic nerves in detail. Thin-slice technique was crucial for this method, as well as fat-suppressed and blood flow-suppressed imaging.

关键词： Two-dimensional magnetic resonance neurography neurotmesis traumaticneuroma sciatic nerve peripheral nerve injury neural regeneration

Cooperation in an asymmetric volunteer's dilemma game with relatedness

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2012年第16期57卷 1972-1981页

作者： HE JunZhou WANG RuiWu CHRISTOPHER X J Jensen li yaotang li ChaoQian School of Mathematics and Statistics Yunnan UniversityKunming 650091China State Key Laboratory of Genetic Resources and Evolution Kunming Institute of ZoologyChinese Academy of SciencesKunming 650223China Department of Mathematics and Science School of Liberal Arts and SciencesPratt Institute200 Willoughby AvenueBrooklynNY 11205USA

What motivates some members of a social group to voluntarily incur costs in order to provide for the common good? This question lies at the heart of theoretical and empirical studies of cooperative behavior. This is also the question that underlies the classic volunteer's dilemma model, which has been previously explored in scenarios where group members are related or interact asym- metrically. Here we present a model that combines asymmetry and relatedness, showing that the probability of volunteerism in such systems depends closely on both the degree of asymmetry and level of relatedness between interacting individuals. As has been shown in previous volunteer's dilemma models, the payoff ratio and overall group size also influence the probability of volunteerism. The probability of volunteerism decreases with increasing group size or decreasing cost-to-benefit ratio of the coplayers; in the presence of asymmetrical interactions, subordinate players were more likely to offer public goods than the dominant player. More asymmetrical interactions decrease the probability of volunteerism of the dominant player; overall volunteerism increases with increasing relatedness.

关键词：不对称性志愿者关联性合作游戏相互作用社会团体关联程度

在线全文

学校读者我要写书评

暂无评论

块迭代解法收敛性的判别条件

西安电子科技大学学报 1998年第2期25卷 198-203页

作者：李耀堂西安交通大学理学院

给出了一般ｎ阶线性方程组的几个基本块迭代解法——ＢＪ、ＢＧＳ、ＢＳＯＲ、ＢＪＯＲ、ＢＡＯＲ及ＢＳＡＯＲ迭代解法收敛的一些判别条件．这些条件为上述迭代法收敛性的判定提供了实用判据．

关键词：线性方程组块迭代解法收敛性

THE FACTORIZATIONS OF GENERIC FIEDLER MATRIX

在线全文

学校读者我要写书评

暂无评论

Numerical Mathematics A Journal of Chinese Universities(English Series) 2000年第S1期9卷 18-21页

作者： li yaotang Zhao liquan(Dept.of Math.,Yunnan University,Kunming 650091,PRC)

The concept of Fiedler matrices was introduced in [1] by L. Stuart and ***[1], they investigated the factorization of Fiedler matrix into Fiedler matrices and pre-sented some open questions i. e. When is a Fiedler matrix factorizable as a product ofFiedler matrices? Are there useful sufficient conditions? If a Fiedler matrix is factorizable,are the factors unique? If not, are the dimensions of the factors unique? In this paper,

关键词： Case more THE FACTORIZATIONS OF GENERIC FIEDLER MATRIX than

在线全文

学校读者我要写书评

暂无评论

我国声表面波研究与发展

应用声学 1999年第4期18卷 3-7页

作者：李耀堂四川压电与声光技术研究所重庆400060

本文综述了我国声表面波研究简要发展历程及现状，指出了今后我国声表面波研究发展的重点。

关键词：声表面波 SAW 器件中国研发现状