Enumeration of unlabelled bicolored graphs by degree parities

This paper gives an ordinary generating function for unlabelled bicolored graphs with a given number of odd vertices, where the cardinalities of the bipartite sets are equal. Moreover, the generating functions for the cardinality of each bipartite set from 1 to 8 are listed.     

Asymptotic Methods of Enumeration and Applications to Markov Chain Models

Abstract

The purpose of this article is to present analytic methods for determining the asymptotic behaviour of the coefficents of power series that can be applied to homogeneous discrete quasi death and birth processes. It turns that there are in principle only three types for the asymptotic behaviour. The process either converges to the stationary distribution or it can be approximated in terms of a reflected Brownian motion or by a Brownian motion. In terms of Markov chains these cases correspond to positive recurrence, to null recurrence, and to non recurrence. The same results hold for the continuous case, too.     

农业普查中全面查点与样本查点的比较

农业普查中全面查点与样本查点的比较朱向东在农业普查中,对所有的农业生产经营单位进行调查,叫全面查点;仅对样本进行调查,叫样本查点。目前,在世界农业普查中,多数国家采用全面查点的方法,部分国家采用样本查点的方法,还有一部分国家采用两者结合的查点方法。本...     

留守与流动儿童登记与调查体系的设计与实施

 本文通过对留守与流动儿童定义分歧的梳理及要素特征分析,明确“留守”与“流动”儿童的概念、内涵与外延;设计以“户籍资料”为基础,分别构建以“教育部门”、“公安部门”为主的留守、流动儿童登记体系,建立关于留守与流动儿童登记的长效机制。针对留守与流动儿童这两类特殊群体,设计研究的调查表,该表由基本信息与综合信息两部分组成,并构建以“登记表信息及户籍信息”为依据,以“统计部门为主”统计调查体系。通过留守与流动儿童登记与调查体系的设计,并加以实施,便于准确地掌握情况、了解问题,为留守与流动儿童的学术研究提供基础的信息资料,为相关部门制定对策提供必要的依据。     

“普遍二孩”政策下我国未来人口结构仿真

文章基于系统动力学模型,对未来实施“普遍二孩”政策后我国的人口结构进行仿真研究,获知由于城乡居民生育意愿走低,我国人口结构问题、人口老龄化问题无法通过“普遍二孩”政策予以根本解决.通过比较“单独二孩”和“普遍二孩”政策,凸显后者在应对我国人口问题上一定的优越性,建议“普遍二孩”政策应非我国人口政策的最终落脚点,国家应根据政策实施结果积极进行人口政策的再调整,最终实现人口长期均衡发展.     

农民工子女教育的社会援助效果

农民工子女教育问题本质上是三农问题在教育领域的延伸。农民工子女是教育弱势群体,而社会援助能有效解决农民工子女教育面临社会支持不足的问题。运用双重差分模型和三重差分模型评估获得社会援助对农民工子女学业成绩产生的影响,研究结果表明:获得社会援助有助于农民工子女的学业成绩提高;成绩差的农民工子女的社会援助效果更好;心理援助和物质援助相结合对农民工子女学业成绩的促进作用更大,尤其是对成绩差的农民工子女。     

Serials in Service to Children and Youth

Librarians in school and public libraries offer insights into the development and management of their serials collections. They explain how they strive to meet the diverse needs of their young library users.     

Acute Middle Ear Infection in Small Children: A Bayesian Analysis Using Multiple Time Scales

The study is based on a sample of 965 children living in Oulu region (Finland), who were monitored for acute middle ear infections from birth to the age of two years. We introduce a nonparametrically defined intensity model for ear infections, which involves both fixed and time dependent covariates, such as calendar time, current age, length of breast-feeding time until present, or current type of day care. Unmeasured heterogeneity, which manifests itself in frequent infections in some children and rare in others and which cannot be explained in terms of the known covariates, is modelled by using individual frailty parameters. A Bayesian approach is proposed to solve the inferential problem. The numerical work is carried out by Monte Carlo integration (Metropolis-Hastings algorithm).     

Improving The Efficiency of The Case-Crossover Design

The case-crossover design has been used by many researchers to study the transient effect of an exposure on the risk of a rare outcome. In a case-crossover design, only cases are sampled and each case will act as his/her own control. The time of failure acts as the case and non failure times act as the controls. Case-crossover designs have frequently been used to study the effect of environmental exposures on rare diseases or mortality. Time trends and seasonal confounding may be present in environmental studies and thus need to be controlled for by the sampling design. Several sampling methods are available for this purpose. In time-stratified sampling, disjoint strata of equal size are formed and the control times within the case stratum are used for comparison. The random semi-symmetric sampling design randomly selects a control time for comparison from two possible control times. The fixed semi-symmetric sampling design is a modified version of the random semi-symmetric sampling design that removes the random selection. Simulations show that the fixed semi-symmetric sampling design improves the variance of the random semi-symmetric sampling estimator by at least 35% for the exposures we studied. We derive expressions for the asymptotic variance of risk estimators for these designs, and show, that while the designs are not theoretically equivalent, in many realistic situations, the random semi-symmetric sampling design has similar efficiency to a time-stratified sampling design of size two and the fixed semi-symmetric sampling design has similar efficiency to a time-stratified sampling design of size three.     

The Demand for Lotto: The Role of Conscious Selection

This article presents estimates of the elasticity of demand for lottery tickets using time series data in which there is variation in the expected value of a lottery ticket induced by rollovers. An important feature of our data is that there are far more rollovers than expected given the lottery design. We find strong evidence that individuals do not choose their lottery numbers uniformly from a uniform distribution—that is, conscious selection. We use our estimates to derive the inverse supply function for the industry, and this enables us to identify the demand elasticity. We find the price elasticity to be close to unity, which implies that the operator is revenue maximizing—which is the regulator's objective.     

相关性分析中Copula函数的选择

Copula函数在金融分析和风险管理中有广泛的应用,利用Copula函数可以构建组合风险资产的联合收益分布和资产之间的相关性.在构建Copula模型时,一个关键的问题就是如何选择最佳的Copula来拟合实际的金融数据.文章分析了Copula函数选择困难的原因,指出了现有的似然准则选择方法的不足,提出了基于参数Bootstrap技术的对数似然准则检验方法,考虑了更大范围的Copula函数族群,利用模拟实验检验了该方法的选择能力,模拟结果表明对于没有尾部相关性的Copula函数和具有较小的尾部相关性的Copula函数可以较好地进行区分,而且也能区分大部分的具有较大尾部相关系数的Copula函数.同现有的只能区分常见的几类Copula的似然准则选择方法相比,文章提出的方法可以在更大范围内识别不同的Copula函数.     

知否，知否，应是绿肥红瘦——对于随机性的探讨

基于数据的时间序列形式与动力系统之间的关系,笔者从网上下载了近10年的1000多篇相关的论文,表1是对这些文章的一个基本分类。以下是对国内外1006篇论文进行的分类。这个基本的百分比告诉了许多信息,研究的出发点是时间序列数据分析对随机性概念的运用与界定。这1000多篇论文普遍体现了实验统计学的理念。一些基本概念,比如随机性在实验的角度被加以探讨和拓展。因为随机性是统计学的一个基本概念,它是统计学的一些工作型的运算能够得以进行的基础。随机性的概念一般可以分为四个类型:(1)常识型的随机性概念,这种类型的概念通常是人们在交…