Performance ratios of the Karmarkar-Karp differencing method

We consider the multiprocessor scheduling problem in which one must schedule n independent tasks nonpreemptively on m identical, parallel machines, such that the completion time of the last task is minimal. For this well-studied problem the Largest Differencing Method of Karmarkar and Karp outperforms other existing polynomial-time approximation algorithms from an average-case perspective. For m ≥ 3 the worst-case performance of the Largest Differencing Method has remained a challenging open problem. In this paper we show that the worst-case performance ratio is bounded between . For fixed m we establish further refined bounds in terms of n.     

妇女社会经济特征对子女数影响的泊松回归分析——基于对乌鲁木齐市维吾尔族妇女的调查

利用随机抽取的乌鲁木齐市800户维吾尔族家庭状况数据,使用专用统计模型泊松回归分析了维吾尔族妇女的社会经济特征对家庭子女数的影响,同时考察了计划生育政策的影响作用。分析发现,维吾尔族妇女的受教育程度、就业状况和计划生育政策对家庭子女数的影响具有统计学显著意义。     

四川流动人口规模及其流向特征分析

四川是一个流动人口大省。人口的迁移流动对四川乃至全国的经济、社会产生着重要影响。本文利用全国第五次人口普查资料,从多个层面对四川的流动人口规模、流向特征进行了分析。     

论数的概念与毕达哥拉斯数的哲学

在米利都自然哲学之后 ,希腊哲学转向寻求超感性的纯思想是有其必然性的 ,奥菲斯教的思想内容正是第一个超感性的纯思想 :存在概念。而数的概念是以存在概念为惟一前提的。因此说 ,毕达哥拉斯的奥菲斯教信仰对他的哲学必然起了重大作用。纯数学产生于毕达哥拉斯 ,且只有希腊人有纯数学 ,原因就在这里     

“参伍以变，错综其数”与《洛书》

“参伍以变，错综其数”并非是讲《九宫数图》的数字规律“纵横交错，都是十五”，它是对《周易》筮法的核心内容“三变成爻”的具体操作形式的概括性描述。     

A CONSISTENT MODEL SPECIFICATION TEST BASED ON THE KERNEL SUM OF SQUARES OF RESIDUALS

This paper constructs a consistent model specification test based on the difference between the nonparametric kernel sum of squares of residuals and the sum of squares of residuals from a parametric null model. We establish the asymptotic normality of the proposed test statistic under the null hypothesis of correct parametric specification and show that the wild bootstrap method can be used to approximate the null distribution of the test statistic. Results from a small simulation study are reported to examine the finite sample performance of the proposed tests.     

两态系统中数──相的压缩特性及其最小测不准态

本文由Ｐ－Ｂ位相表述［１］、［２］及Ｖ．Ｂｕｉｅｒ有限维相干态中的位相特性［３］，具体计算了两态系统中数，相算符在相干态中的期待值、测不准量和压缩特性。     

On the asymptotic expectation and variance of the number of boundary crossings

Let X₁,X₂,… be independent and identically distributed nonnegative random variables with mean μ, and let S_n = X₁ + … + X_n. For each λ > 0 and each n ≥ 1, let A_n be the interval [λn^Y, ∞), where γ > 1 is a constant. The number of times that S_n is in A_n is denoted by N. As λ tends to zero, the asymtotic behavior of N is studied. Specifically under suitable conditions, the expectation of N is shown to be (μλ^?1)^β + o(λ^?β/2 where β = 1/(γ-1) and the variance of N is shown to be (μλ^?1)^β(βμ¹)²σ² + o(λ^?β) where σ² is the variance of X_n.     

中国城镇居民收入性别差异

 现有对中国居民收入性别差异的研究都是基于个人收入样本数据,进行收入差异均值分解和歧视定量研究。指数基准问题是横亘其中一道绕不过去的坎。本文基于人们对其收入是否合理进行主观评价的指标,来选择指数基准以深入研究城镇居民收入的性别差异。本文的计算结果显示,按照经典的Blinder-Oaxaca模型和Cotton模型计算,收入的性别歧视被大大低估。     

辽宁省出生人口萎缩与生育政策调整研究

辽宁省育龄妇女数量和出生人口数量多年来一直呈减少趋势,生育水平已经进入超低状态,尽管面临新的生育高峰,但由于生育旺盛期育龄妇女人数的减少,也不会引起出生人口的较大反弹.因此,必须在适当的时候调整生育政策,将总和生育率提高到一定的水平,以维持合理的人口再生产.