检索结果-南通市图书馆

EXISTENCE OF 0-1 UNIVERSAL MINIMAL TOTAL DOMINATING FUNCTIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2004年第4期17卷 485-491页

作者： FANGQizhi epartmentofmathematics OceanUniversityofChinaQingdao266071ShandongChina

In this paper, we study the existence of 0-1 universal minimal total dominating functions in a graph. We establish a formulation of linear inequalities to characterize universal minimal total dominating functions and show that for a kind of graphs whose adjacent matrices are balanced, the existence of universal minimal total dominating functions coincides with that of 0-1 ones. It is also proved that for general graphs, the problem of testing the existence of 0-1 universal minimal total dominating functions is NP-hard.

关键词： total dominating function (TDF) minimal total dominating function (MTDF) universal mtdf balanced NP-hard

Comparative analysis of temperature and CO2 fluxes for winter wheat in Tibetan Plain and North china Plain using the EMD method

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第10期16卷 1066-1071页

作者： JIANG Zhaoyang, YU Qiang, LEI Shuhe, WANG Tianduo, SUN Xiaomin and ZHANG Renhua ( Chinese Academy of Meteorological Science, Beijing 100081, china Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, china mathematics department, ocean university of china, qingdao 266071, china Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, china) Chinese Academy of Meteorological Science Beijing 100081 China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China mathematics department Ocean University of China Qingdao 266071 China Shanghai Institute of Plant Physiology and Ecology Chinese Academy of Sciences Shanghai 200032 China

Comparative study of spectral properties of temperature and CO2 fluxes measured by eddy covariance method at Yucheng (36°57'N, 116°36'E, 28 m a.s.l., in the North china Plain) and at Lhasa (29°41'N, 91°20'E, 3688 m a.s. 1., on the Tibetan Plateau) is described using the empirical mode decomposition (EMD) method. The main results are: (1) The intrinsic oscillation modes or intrinsic mode functions (IMFs) were extracted from data of temperature ( T) and CO2 fluxes (F) measured at Yucheng ( T1 and F1) and Lhasa ( T2 and F2) . (2) Hilbert transform was applied to these IMF components, then the Hubert-Huang spectra and the marginal spectra of these data were obtained. (3) Comparison of temperature and CO2 fluxes in North china Plain and on Tibetan Plain illustrated that the characteristic frequencies corresponding to T1, F1, T2 and F2 are 0.05 Hz, 0.03 Hz, 0.014 Hz and 0.005 Hz, respectively.

关键词： empirical mode decomposition (EMD) intrinsic mode function (IMF) flux Hilbert transform wheat Tibet.

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

一类S-分布时滞递归神经网络的全局吸引子

山东大学学报（理学版） 2009年第4期44卷 57-60页

作者：梁霄王林山中国海洋大学数学科学学院山东青岛266071

研究了一类S-分布时滞递归神经网络的渐近行为,通过构造一类带有Razuminkhin条件的Lyapunov函数,证明了系统的耗散性。利用算子分解的方法讨论了网络模型的渐近紧性,结合吸引子的理论给出了全局吸引子存在的充分条件。

关键词：全局吸引子 Lyapunov函数渐近紧

A NOTE ON THE BACKWARD ERRORS FOR INVERSE EIGENVALUE PROBLEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational mathematics 2003年第2期21卷 201-206页

作者： Xinguo Liu Zhengjian Bai (department of mathematics, ocean university of china, qingdao 266071) Departmenl of mathematics Ocean University of China Qingdao 266071

In this note, we consider the backward errors for more general inverse eigenvalue problems by extending Sun's approach. The optimal backward errors are defined for diagonal-ization matrix inverse eigenvalue problem with respect to an approximate solution, and the upper and lower bounds are derived for the optimal backward errors. The results may be useful for testing the stability of practical algorithms.

关键词： Inverse eigenvalue problem Optimal backward error Upper bound Lower bound

The extension of the first main theorem for π-blocks

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2006年第5期49卷 620-625页

作者： HAI Jinke department of mathematics, qingdao university, qingdao 266071, china College of mathematics ,Shandong university, Jinan 250100, china department of mathematics Qingdao University Qingdao China College of mathematics Shandong University Jian China

Let π be a set of primes and G a π-separable group. Isaacs defines the Bπ characters, which can be viewed as the "π-modular" characters in G, such that the Bp′ characters form a set of canonical lifts for the p-modular characters. By using Isaacs' work, Slattery has developed some Brauer's ideals of p-blocks to the π-blocks of a finite π-separable group, generalizing Brauer's three main theorems to the π-blocks. In this paper, depending on Isaacs' and Slattery's work, we will extend the first main theorem for π-blocks.

关键词： π-block, π-separable group, π-regular classes, defect group.

ON RAYLEIGH QUOTIENT MATRICES: THEORY ANDAPPLICATIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational mathematics 1999年第6期17卷 629-638页

作者： Xin-guo Liu(department of Applied mathematics ocean university of qingdao, qingdao 266003, china) 青岛海洋大学应用数学系山东青岛 266003

Many authors have studied the Rayleigh quotient and Rayleigh quotient matrix. This paper consists of two parts. First, generalizations of some results on the Rayleigh quotient are proved. Second, we give some applicat... 详细信息

关键词： Rayleigh quotient matrix eigenvalue approximation

On Browkin's conjecture about the elements of order five in K_2(Q)

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2007年第1期50卷 116-120页

作者： Ke-jian XU department of mathematics, qingdao university, qingdao 266071, china department of mathematics Qingdao University Qingdao China

Based on the work of Lenstra, a succinct proof of Browkin’s conjecture about the elements of order five in K2(Q) is given.

关键词： K2 group cyclotomic polynomial lattice binary quartic form.

The advancement of oscillation theory of functional differential equations

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

Chinese Science Bulletin 1998年第12期43卷 974-982页

作者： ZHANG Binggen department of Applied mathematics, ocean university of qingdao, qingdao 266003, china department of Applied mathematics Ocean University of Qingdao Qingdao China

The oscillation theory of functional differential equations (FDEs) is surveyed including (ⅰ) formulation of oscillation problems; (ⅱ) a brief history of the oscillation theory of FDEs; (ⅲ) main topics in the oscill... 详细信息

关键词： functional differential equations oscillation theory.

On the torsion in K_2 of a field

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2008年第7期51卷 1187-1195页

作者： XU KeJian & LIU Min College of mathematics,qingdao university,qingdao 266071,china College of mathematics Qingdao University Qingdao China

For a field F,let Gn(F) = {{a,Φn(a)} ∈ K2(F) | a,Φn(a) ∈ F*},where Φn(x) is the n-th cyclotomic *** first,by using Faltings' theorem on Mordell conjecture it is proved that if F is a number field and if n = 4,8,12 is a positive integer having a square factor then Gn(F) is not a subgroup of K2(F),and then by using the results of Manin,Grauert,Samuel and Li on Mordell conjecture theorem for function fields,a similar result is established for function fields over an algebraically closed field.

关键词： number field function field torsion Milnor K2-group Mordell conjecture