基于时间—区域序列的随机死亡率预测及对中国数据的应用

由美国学者Lee,Tulj(?)parkar和Carter于1991年提出的随机人口预测(LTC)方法,既弥补了传统的“高一低”方案所无法回答发生某个状态的概率的缺点,又解决了经典的随机人口模型不能处理按龄生育、死亡率的随机性时变的困难。介绍了(LTC)方法的主要内容,并通过将其中时间序列模型扩展为时间—区域序列模型,解决了该方法用于发展中国家的常见困难即死亡率时间序列数据不足的问题。同时利用中国死亡率数据进行(LTC)方法的建模和预测,取得了良好的效果。     

考虑人口年龄结构变动的中国消费函数计量分析--兼论中国人口老龄化对消费的影响

本研究通过对中国自1978年以来的时间序列数据的分析,引入标准消费人概念和变量,有效地解决了消费函数中人口年龄结构影响的分析问题。引入人口年龄结构的消费函数得到检验通过,可以用于对中国总体消费规律的分析和未来的预测。     

基于BP神经网络人口预测模型的研究与应用

人口问题是21世纪中国所面临的重大问题,同时也是关系到社会发展的重要因素。因此人口预测,作为经济、社会研究的一种方法越来越受到人们的重视。对人口数据进行知识的发现,可以了解未来人口的演化进程,从而对连带的一系列的社会问题如教育、劳动力结构等有一个充分的认识。正确的人口预测结果将对政府制定与此相关的政策意义重大。利用数据挖掘中的BP神经网络技术,构建了人口预测模型,并根据实际数据利用该模型进行了实证预测。     

中国人口时间序列预测模型的探讨

以 1 95 2～ 2 0 0 2年人口序列数据为基础 ,构建了中国人口时间序列预测模型 ,采用一般回归法、后退法和逐步回归法三种方法对所设计的模型进行估计 ,得到 72个模型。然后 ,从中筛选出估计标准误较小 ,自相关影响基本消除的预测模型。作为中国人口总量的预测模型 ,我们提出的预测模型有估计精度高 ,误差低的特点 ,是目前用自回归方法估计得出的较好的中国人口预测模型。     

中国人口的不确定性研究

文章对2000年人口普查所反映的生育水平、出生性别比和人口年龄结构等主要人口指标存在的不确定性进行了梳理,并运用概率人口预测方法系统讨论了中国未来人口变动趋势过程中相关人口变量的不确定性问题。结果显示,当前对中国生育率水平、出生性别比和低龄儿童人口数量的估计都存在很大的差异。这些差异直接影响中国人口目前和未来的不确定性。     

中国城镇、农村人口发展趋势预测

本文根据现阶段人口变动的情况，对中国未来人口发展进行了预测。人口预测的模型不仅考虑到城镇、农村在生育、死亡等方面的差异，而且也反映农村人口向城镇的动态迁移。在人口预测的生育模式上采用了总和递进生育率的指标，将妇女按所生孩次的结构分类。本文所作的预测为长期预测，对中国至２０５０年的总人口、城镇和农村人口发展以及人口的年龄结构作了较为详细的预测。     

对Г—分布生育模式的讨论

在人口模型中,人口的生育模式是一个很难确定的量,尤其在人口预测中,对生育的预测必须要找到一种能够描绘未来人口生育过程的生育模式。在近年的人口模型和人口预测方法中,很多人采用了数学上的Г—分布,作为描述人口生育模式变动的数学曲线,有人认为该曲线能够用来代替实际人口的生育模式,也有人认为它不能代替。那么Г—分布到底是一种什么样的函数,它是否能用于描述人口的生育模式,下面我们对这两个问题进行讨论。     

我国人口预测中的一个问题

人口预测是在现有人口状况的基础资料上,考虑未来各种因素对人口发展的影响,运用人口变量及相关因素之间的内在联系,建立数学模型,进行运算,取得的未来人口发展势趋的基本资料。 人口预测的科学与否,应该首先建立在人口状况的基础资料上,人口现状基础资料是制约人口发展的客观因素。当然人口预测也不能因此而忽视影响人口发展的其它因素,如计划生育方针政策、社会经济、思想意识等因素,但它们仅仅是相关因素。目前国内进行人口预     

凉州区未来人口发展趋势及其社会影响

人口因素是凉州区社会经济发展的重要因素，人口的增长趋势将影响到凉州区未来社会经济目标的实现。本文根据凉州区第五次人口普查资料，运用中国人口预测软件（CPPS）对凉州区2050年前的人口发展趋势进行了预测，分析了未来凉州区人口发展的特征及其社会影响，并对相关问题提出了建议。     

人口密度和生育率:一项探索性分析

20世纪是世界人口前所未有的增长期。文章利用世界187个国家1960～2000年(间隔5年)的时间序列资料,结合中国、印度和瑞典的个案分析,着重研究人口密度与人口增长率、生育率之间的关系。研究结果表明,人口密度是除影响人口增长率和生育率下降的社会、经济、文化变量之外的另一个重要因素,它直接影响生育率的水平和趋势,在未来人口预测中有必要考虑人口密度变量。中国、印度和瑞典的案例也反映出人口密度与生育率之间的显著相关关系。     

Leslie matrix models

A review of the Leslie matrix model theory and its literature 1941-1987 is presented. The point of view is that of a mathematician who focuses on the parts of the theory which are relevant to demography. Works of a decidedly applied nature are not dealt with.     

Populations with constant immigration

We consider a Leslie‐type model of a one‐sex (female) population of natives with constant immigration. The fertility and mortality schedule of the natives may be below or above replacement level. Immigrants retain their fertility and mortality, their children adopt the fertility and mortality of the natives. It is shown how this model may be written in a homogeneous form (without additive term) with a Leslie‐type matrix. Reproductive values of individuals in each age group are discussed in terms of a left eigenvector of this matrix. The homogeneous form of our projection model permits the transformation into a Markov chain with transient and recurrent states. The Markov chain is the basis for the definition of genealogies, which incorporate immigration. It is shown that genealogies describe the life histories of individuals in a population with immigration. We calculate absorption times of the Markov chain and relate them to genealogies. This extends the theory originally designed for closed populations to populations with immigratioa     

Leslie matrix models

A review of the Leslie matrix model theory and its literature 1941–1987 is presented. The point of view is that of a mathematician who focuses on the parts of the theory which are relevant to demography. Works of a decidedly applied nature are not dealt with.     

Simple bounds for the dominant eigenvalue of a generalized Leslie matrix

"Simple bounds are presented for the dominant eigenvalue of the generalized Leslie matrix of a multiregional demographic growth model." (SUMMARY IN FRE)     

A problem in household composition

"Distinction made between household-persons and household-markers [the person who identifies the family or household as a unit] is formalized in the notion of nested populations. This leads to an extension of the Leslie model into a formulation of growth for both population and households. The extended model involves the matrix presentation of household composition where ratios of household-persons who are age 0, per household-marker, function as surrogate values for fertility rates. The extended model describes change over time in the distribution of population by age, and in the distribution of households by age of household-marker, or household-head. The model involves the inversion of a nonnegative matrix, and is feasible only if it yields, projected over time, nonnegative entries in vectors representing distribution of population by age, and distribution of household-heads by age. Conditions for the feasibility of the extended model are discussed, and a sufficient condition for feasibility over a single interval is identified." (SUMMARY IN FRE)     

Sensitivity analysis of discrete-time interregional population systems

This paper shows analytically how (a) the long-run growth rate and (b) the long-run proportional distribution of an interregional population system with a time-homogeneous structural matrix are affected by small changes or errors in (a) the natural growth rates of individual regions and (b) the interregional migration rates. Furthermore, the analytic results are applied to an eight-region Canadian population system. Finally, it is claimed that the method introduced here can be easily applied to sensitivity analysis of both the intrinsic growth rate and the “stable” age-composition of the Leslie model with respect to changes in age-specific birth and survival rates.     

On the intrinsic force of convergence to stability∗

Observed populations differ greatly in the speed with which they approach the stable form, but what determines rates of convergence is not fully understood. The present paper shows that the force of convergence does not approach a fixed value, but oscillates indefinitely around an “intrinsic”; level. That level, h?, is determined by the square of the ratio of the 2 largest eigenvalues of the Leslie matrix. The value of h? can be closely approximated by a simple function that changes directly with the square of the coefficient of variation and inversely with the mean of the stable net maternity function. Population entropy, another measure of dispersion relative to the mean, is also highly correlated with h?.     

我国个体经济的就业研究

本文利用柯布—道格拉斯生产函数建立个体经济的就业函数,并利用1981～2007年个体经济发展的数据建立ARMA模型分析我国个体经济的就业与资金、收入等变量的关系,发现其吸纳就业的能力与营业收入、注册资金总额都成正比。     

Yearly variation in recruitment and its effect on population dynamics inYoldia notabilis (Mollusca: Bivalvia), analyzed using projection matrix model

Summary Long-term variation in recruitment was estimated by constructing projection matrices for a marine bivalve,Yoldia notabilis, at two stations in Otsuchi Bay, northeastern Japan, and the effects of its variation on population dynamics were examined using a simple matrix model. The matrix model was developed from the Leslie matrix, in which the population growth rate λ was expressed as a function of recruitment rater ₀. The equilibrium recruitment rater _s, or the recruitment rate required to maintain population at constant size (λ=1), was expressed by the reciprocal of the reproductive value of a newly recruited individual. The estimates ofr _s for the field population were lower at the shallower station than at the deeper station, reflecting higher survivorship and fecundity. Past recruitment rate estimated both by the field samplings for 3 years and by the back-calculation from the current age structure for over 10 years showed large yearly variation, ranging between 0 and 58.6×10⁻⁴. The estimates were larger thanr _s, and hence, large enough to increase population size (λ>1) only in approximately one-third of the estimated years. This suggests that the population has been maintained by occasional successful recruitment occurring once every few years.     

Compensating changes in fertility and mortality

This paper illustrates a method of studying changes in vital rate schedules which have no effect on the intrinsic rate of population growth. These changes are described as compensating changes in fertility and mortality. The analysis proceeds from the discrete perspective of Leslie matrices, wherein the central idea is to establish the set of all compensating changes by identifying that class of Leslie matrices which possess the same positive eigenvalue, λ₁. A root-squaring technique is adapted for the purpose of estimating λ₁. Finally, a variety of compensating fertility and mortality changes is illustrated using data from Japan.