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1.
带准备时间的自由作业排序问题—最坏性能比分析   总被引:2,自引:0,他引:2  
本文研究了一类自然的排序问题,带准备时间的自由作业排序。在机器台数任意的情况下,证明了一个简单的贪婪算法的最坏性能比不超过2,并猜想该算法的临界为2-1/m,其中m为机器台数。特别当m=2时,证明了该算法的最坏性能比恰为3/2。  相似文献   

2.
本文引进了工作带有准备时间的组装线排序问题。在第一阶段用m台机器来生产带有准备时间的工件的零部件。第二阶段用一台机器来组装这些零部件。目标是使总完工时间最小。我们给出了一个启发式算法,并证明了其最差情况性能比等于或小于8/3-1/m。  相似文献   

3.
可拆分平行机排序问题研究   总被引:2,自引:0,他引:2  
平行机排序问题是把n个产品安排到m台机器上加工,使其总费用最小.通常的平行机排序问题都假设(C1):任何产品不能在不同机器上同时加工.但是,如果把产品的加工时间看成一个产品量的需求,就可以假设(C2):允许同一产品拆分在不同机器上同时加工.本文首先回顾了C1假设下平行机排序问题已有的结果,然后基于假设C2,讨论了各种费用目标下问题的算法及其复杂性.在没有生产准备时间的情况下,给出了一些问题的多项式算法和线性规划方法.在有独立生产准备时间的情况下,给出了P/split/Cmax问题的启发式算法及其算法分析.  相似文献   

4.
一类指数型整函数值算子的逼近性质   总被引:2,自引:0,他引:2  
王梅英 《数学杂志》1999,19(1):11-18
设(Uσf)(x)=Σ↓k∈Zf(Xk)Aσ(X-Xk),Xk=2kπ/σ,k∈Z,σ〉0,f是R上的有界函数,而Aσ(y)=2/σ∫σ0sin^m(σ-X)h/sin^m(σ-X)h+sin^mxhcosxydx,m为奇自然数,0〈h〈π/σ,本文研究了此插值算子的收敛与饱和问题。  相似文献   

5.
设(Xi,Yi)1≤i≤n为来自二元总体(X,Y)的平稳,φ-混合样本,记m(x)△E(Y│X=x),m(x)的一种递推型核估计为mn(x)=n∑i=1hi^-1Yik((x-Xi)/hi)/n∑j=1h^-1jk(x-Xj)/hj)。本文在一定的条件下证明了(n/(n∑j=1h^-1j)^1/2)(mn(x1)-m(x1),mn(x2)-m(x2),...mn(xr0)-m(xr0))′依分布收  相似文献   

6.
设G=Gn(i1,i2,…,ir)是连通循环图,且x(G)〈δ(G),本文得到了其连通度的明确表达式:x(G)=min(m/M(n/m,K)/:m是n的真因子,且/M(n/m,K)/〈n/m-1)。  相似文献   

7.
本文首先引入Besel(Riesz)位势K¨othe函数空间Xs(Xs)的概念,然后讨论一类算子在Lebesgue-位势K¨othe函数空间Lq(-T,T;Xs)上的对偶估计.由此我们得到半群exp(it(-Δ)m/2)和算子A:=∫t0exp(i(t-τ)(-Δ)m/2)·dτ在Lebesgue-Besov空间Lq-T,T;·Bsp,2中的一些时间--空间Lp-Lp′估计.本文的系列文将给出这些估计的应用  相似文献   

8.
两台平行机的实时到达在线排序   总被引:2,自引:0,他引:2  
本文考虑一的的在线平行机排序模型--实时到达在线问题,该模型中,工件是陆续到达的,工件的个数及到达时间是事先未知的,而且只有当工件到达,才知其加工时间,所求目标是使所有工件都加工完的时间达到最小,对两台平行机的情形,Chen与Vestjens给出近似比为3/2的线LPT算法,并证明了不存在近似小于(5-√5)/2的算法,我们利用黄金分割数设计了一个 算法,其近似比不超过(18-√5)/11。  相似文献   

9.
建立如下权系数的不等式:1+1mm≤e1-1-2/em(m=1,2,…),这里,1-2/e=0.2642411+为最佳值.从而得到一个加强的Carleman不等式.  相似文献   

10.
关于分圆多项式的Schinzel等式   总被引:1,自引:0,他引:1  
任德斌  孙琦 《数学学报》2002,45(1):187-190
对一无平方因子的奇数n>1, 分圆多项式φn(x)  满足Schinzel等式, φn(x)=P2n,m(x)-(-1/m)mxQ2n,m(x),  这里Pn,m(x)和 Qn,m(x)是整系数多项式且 m|n.本文给出两个简明的公式来计算 Pn,m(x) 和 Qn,m(x)  .  相似文献   

11.
12.
As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years (2001-2005). The main topics are: convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.  相似文献   

13.
Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.  相似文献   

14.
15.
正Applied Mathematics-A Journal of Chinese Universities,Series B(Appl.Math.J.Chinese Univ.,Ser.B)is a comprehensive applied mathematics journal jointly sponsored by Zhejiang University,China Society for Industrial and Applied Mathematics,and Springer-Verlag.It is a quarterly journal with  相似文献   

16.
正Journal overview:Journal of Mathematical Research with Applications(JMRA),formerly Journal of Mathematical Research and Exposition(JMRE)created in 1981,one of the transactions of China Society for Industrial and Applied Mathematics,is a home for original research papers of the highest quality in all areas of mathematics with applications.The target audience comprises:pure and applied mathematicians,graduate students in broad fields of sciences and technology,scientists and engineers interested in mathematics.  相似文献   

17.
A cumulative-capacitated transportation problem is studied. The supply nodes and demand nodes are each chains. Shipments from a supply node to a demand node are possible only if the pair lies in a sublattice, or equivalently, in a staircase disjoint union of rectangles, of the product of the two chains. There are (lattice) superadditive upper bounds on the cumulative flows in all leading subrectangles of each rectangle. It is shown that there is a greatest cumulative flow formed by the natural generalization of the South-West Corner Rule that respects cumulative-flow capacities; it has maximum reward when the rewards are (lattice) superadditive; it is integer if the supplies, demands and capacities are integer; and it can be calculated myopically in linear time. The result is specialized to earlier work of Hoeffding (1940), Fréchet (1951), Lorentz (1953), Hoffman (1963) and Barnes and Hoffman (1985). Applications are given to extreme constrained bivariate distributions, optimal distribution with limited one-way product substitution and, generalizing results of Derman and Klein (1958), optimal sales with age-dependent rewards and capacities.To our friend, Philip Wolfe, with admiration and affection, on the occasion of his 65th birthday.Research was supported respectively by the IBM T.J. Watson and IBM Almaden Research Centers and is a minor revision of the IBM Research Report [6].  相似文献   

18.
In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p(R^n) into the Lebesgue space L^p with p 〈 1.  相似文献   

19.
In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.  相似文献   

20.
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