期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
DIRECTED HYPERGRAPH THEORY AND DECOMPOSITION CONTRACTION METHOD
1
作者 黄汝激 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1995年第2期123+114-123,共11页
A new branch of hypergraph theory-directed hyperaph theory and a kind of new methods-dicomposition contraction(DCP, PDCP and GDC) methods are presented for solving hypernetwork problems.lts computing time is lower tha... A new branch of hypergraph theory-directed hyperaph theory and a kind of new methods-dicomposition contraction(DCP, PDCP and GDC) methods are presented for solving hypernetwork problems.lts computing time is lower than that of ECP method in several order of magnitude. 展开更多
关键词 directed hypergraph theory decomposition contraction method hypernetwork
下载PDF
RECURSIVE FORMULAS OF HYPEREDGE DECOMPOSITION SETS
2
作者 黄汝激 钟家桢 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1996年第2期120+115-120,共7页
The concepts of the undirected and directed decompositions are introduced for a hyperedge.Then, the recursive formulas of the underected decomposition set SD(m) and directed decomposition set SPD(m) are derived for an... The concepts of the undirected and directed decompositions are introduced for a hyperedge.Then, the recursive formulas of the underected decomposition set SD(m) and directed decomposition set SPD(m) are derived for an m-vertex hyperedge.Furthermore,the recursive formulas of their cardinalities|SD(m)|and |SPD(m)| are yielded. 展开更多
关键词 active hypernetwork directed hypergraph theory hyperedge undirected decomposition hyperedge directed decomposition.
下载PDF
Male mate choice in Tibetan macaques Macaca thibetana at Mt.Huangshan,China 被引量:3
3
作者 Min ZHANG Jinhua LI +2 位作者 Yong ZHU Xi WANG Su WANG 《Current Zoology》 SCIE CAS CSCD 北大核心 2010年第2期213-221,共9页
Though females are generally more selective in mate choice, males may also benefit from mate choice if male reproductive success is limited by factors other than simply the number of female mates, and if females diffe... Though females are generally more selective in mate choice, males may also benefit from mate choice if male reproductive success is limited by factors other than simply the number of female mates, and if females differ in short-term reproductive potential. We studied male mate choice in a free-ranging troop of Tibetan macaques Macaca thibetana at Mt. Huangshan, China, from August 2007 to April 2008. We employed focal animal sampling and all occurrence sampling to record sexual related behaviors. Eight adult females were divided into three female quality categories according to the females' age, rank and parity. Using male mating effort as a proxy for male mate choice, we found that males do distinguish female quality and show time-variant mating strategies. Specifically, females with dominant rank, high fecundity, and middle age attracted significantly more males. Our results suggest that female short-term reproductive potential appears to be an important variable in determining male mating effort. Male Tibetan macaques do exercise mate choice for higher quality females as well as reduce useless reproductive cost, which is consistent with the direct benefits theory of mate choice. 展开更多
关键词 Tibetan macaques Macaca thibetana Direct benefits theory Male mate choice Reproductive potential Reproductive success
下载PDF
ON THE SINGULAR DIRECTIONS OF VALUE DISTRIBUTION OF HOLOMORPHIC CURVES IN P^n(C) 被引量:2
4
作者 涂振汉 李平丽 《Acta Mathematica Scientia》 SCIE CSCD 2006年第4期702-710,共9页
This article proves the existence of singular directions of value distribution theory for some transcendental holomorphic curves in the n-dimensional complex projective space P^n(C).. An example is given to compleme... This article proves the existence of singular directions of value distribution theory for some transcendental holomorphic curves in the n-dimensional complex projective space P^n(C).. An example is given to complement these results. 展开更多
关键词 Complex projective spaces holomorphic mappings normal families singular directions and value distribution theory
下载PDF
Study of Two Puzzled Questions on the Fullerene C_(70):A First-principles Study
5
作者 陈林刚 陈勇 +2 位作者 李浩宏 李奕 李俊篯 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2011年第4期464-469,共6页
The cycloaddition reactions of NH to different bonds on C70 have been studied by the first-principles calculations.The results indicate that the reactivity of cycloaddition reactions is determined by the directional c... The cycloaddition reactions of NH to different bonds on C70 have been studied by the first-principles calculations.The results indicate that the reactivity of cycloaddition reactions is determined by the directional curvature,KD,and the larger binding energy of Eb on the bond C5-C?5 can be ascribed to the unique bond which can be treated as the shortest bond of(5.5)-SWCNT in the four [6,6] ring fusion bonds.This work also discloses that the energy gap of different spin states is decided by the electronic density,and that of the frontier obitals for the bond C5-C?5 is larger than the value for the C4-C?4 bond.Furthermore,the transition state investigation of the two bond addition reactions provides a reaction barrier of 11.10 kcal/mol for the NH cycloaddition to the C5-C?5 bond;whereas,the addition reaction on C4-C?4 is a spontaneous pathway.Herein,the dynamics effect illustrates the [2+1] cycloaddition reaction on the equatorial C5-C?5 bond to be unfavorable. 展开更多
关键词 C70 FIRST-PRINCIPLES CYCLOADDITION directional curvature theory(DCT)
下载PDF
A theory on spatial correlation and vertical directivity of surface-generated ambient noise in the sea
6
作者 ZHANG Renhe and HE Yi(State key Laboratory of Acoustics, Academia Sinica , Beijing 100080) 《Chinese Journal of Acoustics》 1992年第1期31-40,共10页
A theoretical model of ambient sea noise including surface noise sources and stratified medium ocean is discussed. The noise sources are assumed to be statistically independent directional point sources distributed ov... A theoretical model of ambient sea noise including surface noise sources and stratified medium ocean is discussed. The noise sources are assumed to be statistically independent directional point sources distributed over the ocean surface, and the effects of ocean environment on ambient noise are studied. The normal-mode theory of surface-generated noise is developed, and the normal-mode formula of the directional density function suitable for small grazing angles is analytically continued for being suitable for great grazing angles and consistent with the ray formula. The unified formulae for calculating the intensities, spatial correlation and vertical directivity of ambient sea noise are presented. 展开更多
关键词 A theory on spatial correlation and vertical directivity of surface-generated ambient noise in the sea
原文传递
Asymptotic Marginal Tax Rate of Individual Income Tax in China
7
作者 ZHENYA LIU WU YANG DAVID DICKINSON 《Economic and Political Studies》 2014年第2期121-138,共18页
This paper examines the asymptotic marginal rate of individual income tax which maximizes China's social welfare through numerical simulation based on the elasticity of China's labor supply, income distributio... This paper examines the asymptotic marginal rate of individual income tax which maximizes China's social welfare through numerical simulation based on the elasticity of China's labor supply, income distribution and the social objectives of redistribution in accordance with the optimal direct taxation theory. Taking advantage of the optimal direct taxation model with consideration of the income effect, it comes to the conclusion that combined with China's reality, the asymptotic marginal rate of individual labor income tax in China should be between 35% and 40%. 展开更多
关键词 reform of individual income tax asymptotic marginal tax rate optimal direct taxation theory
原文传递
Social Choice Meets Graph Drawing: How to Get Subexponential Time Algorithms for Ranking and Drawing Problems
8
作者 Henning Fernau Fedor V.Fomin +3 位作者 Daniel Lokshtanov Matthias Mnich Geevarghese Philip Saket Saurabh 《Tsinghua Science and Technology》 SCIE EI CAS 2014年第4期374-386,共13页
We analyze a common feature of p-Kemeny AGGregation(p-KAGG) and p-One-Sided Crossing Minimization(p-OSCM) to provide new insights and findings of interest to both the graph drawing community and the social choice ... We analyze a common feature of p-Kemeny AGGregation(p-KAGG) and p-One-Sided Crossing Minimization(p-OSCM) to provide new insights and findings of interest to both the graph drawing community and the social choice community. We obtain parameterized subexponential-time algorithms for p-KAGG—a problem in social choice theory—and for p-OSCM—a problem in graph drawing. These algorithms run in time O*(2O(√k log k)),where k is the parameter, and significantly improve the previous best algorithms with running times O.1.403k/and O.1.4656k/, respectively. We also study natural "above-guarantee" versions of these problems and show them to be fixed parameter tractable. In fact, we show that the above-guarantee versions of these problems are equivalent to a weighted variant of p-directed feedback arc set. Our results for the above-guarantee version of p-KAGG reveal an interesting contrast. We show that when the number of "votes" in the input to p-KAGG is odd the above guarantee version can still be solved in time O*(2O(√k log k)), while if it is even then the problem cannot have a subexponential time algorithm unless the exponential time hypothesis fails(equivalently, unless FPT D M[1]). 展开更多
关键词 Kemeny aggregation one-sided crossing minimization parameterized complexity subexponential-time algorithms social choice theory graph drawing directed feedback arc set
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部