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1.
Patterns of vaginal bleeding are an important factor in the acceptability of contraceptive methods. The analysis of data obtained from daily menstrual diary records is a major methodological problem to which no satisfactory solution exists. This review describes approaches to the analysis of bleeding patterns among contracepting and non-contracepting women and reviews the difficulties involved. The reference period method, introduced to avoid the arbitrary rules and definitions required for an analysis based on the concept of a menstrual cycle, is discussed and its limitations presented. The review draws on reports of meetings convened by the World Health Organization and the University of Exeter Family Planning Unit to discuss issues in the analysis. Previously unpublished methods are summarized and areas of controversy and topics for further research are identified.  相似文献   

2.
基于黑龙江省第六次人口普查数据,从调整妇女的总和生育率入手,运用宋建的离散人口发展方程模型,并根据建立的人口发展方程分析其死亡率函数、生育率函数等参数方程,进行数值求解,预测出黑龙江省未来50年的人口数量,从中方案的预测结果得出黑龙江省人口将在2015年进入负增长.  相似文献   

3.
Based on the data available through published trial results, we build a mixed integer nonlinear programming (MINLP) model in order to find an optimal treatment plan for a given HR+ early stage breast cancer patient who is postmenopausal. The objective is to maximize the disease-free survival percentage at the end of the treatment period subject to the constraints on the risk of contralateral breast cancer and the risks of several side effects, including endometrial cancer, thromboembolic events, cardiovascular diseases, bone fractures, hot flushes, and vaginal bleeding. The results of numerical experiments suggest the effectiveness of some of the schedules currently used in practice, as well as suggest some attractive alternative treatment plans.  相似文献   

4.
时变人口系统的适定性及关于生育率的最优控制   总被引:11,自引:2,他引:9  
本文对生育率β与时间相关的情形,证明了人口系统的适定性,并讨论了关于生育率β的最优控制问题解的存在性以及人口系统的稳定性.  相似文献   

5.
Data on birth intervals are said to detect current changes in underlying fertility behavior earlier than birth rates and are used especially in developing countries to evaluate family planning programs. Birth interval information comes mostly from retrospective inquiries into maternity histories. Accounting for adolescent sterility and temporary separation between partners, a stochastic model is developed and presented capable of describing the variation in the length of closed birth intervals by birth order for women of a given marriage duration. This model may be used to analyze data on birth intervals in any population where women are exposed to the risk of conception soon after marriage. It is applied to survey data from northern India, whereby the risk of conception and risk of assuming susceptibility to conception following adolescent sterility are estmated along with the maximum duration of adolescent sterility among women with varying ages at consummation of marriage.  相似文献   

6.
Based on Canadian data, this study discusses some of the methods which incorporate fertility variations into population forecasts. In particular, the relative shifts in the age structure which can have profound social and economic consequences on the context of a pay as you go national security system are analyzed. In terms of long range economic and social planning, oscillating growth projections are much more difficult to handle and plan for than the constant growth rates predicted by stable population theories. The impact of different types of fertility fluctuations are analyzed in terms of evolution of the dependency ration over time; the dependency ratio corresponds to the ratio of the retired lives of a population to those of the working age population. From the viewpoint of a social security system, the evolution of the dependency ratio over time is of particular importance. Other areas explored are: 1) cohort fertility variations; 2) periodic fertility fluctuations; and 3) limit cycle behaviors. In the context of a national social security plan, one possible response to the population projections would be to maintain the year by year level of the RA ratio (ratio of the population aged 65 and over to the population aged between 20 and 65) at its equilibrium value of 27.6% by adjusting the retirement age appropriately.  相似文献   

7.
人口问题中的妇女临界生育率   总被引:2,自引:0,他引:2  
本文通过对连续人口模型半离散化,研究了人口发展过程的稳定性和渐近性质,给出了妇女临界生育率,它与[2]中离散情况下临界生育率公式相一致。证明了当比生育率不超过临界生育率时人口状态渐近稳定,而当超过临界生育率时人口指数发散。  相似文献   

8.
人口最优控制的一种方法   总被引:1,自引:0,他引:1  
描述人口动力学通常采用两种模型:连续模型(Sharpe-Lotka 模型)和离散模型(Leslie 模型)。[6]通过对连续人口发展方程按龄离散化得到了时间连续按龄离散的所谓半离散模型  相似文献   

9.
刘治平 《运筹学学报》2021,25(3):173-182
随着高通量技术的发展,越来越多的生物医学组学数据亟需处理与分析,基于运筹优化的生物信息学方法是有效解析高维生物医学数据的重要途径之一。综述了近年来在基因调控网络推断方面的研究进展。针对不同类型的转录组学数据和研究目的,分别建立了相应的基因调控网络推断方法,主要包括先验基因调控网络数据库的建立、基于条件互信息的因果网络推断、基于微分方程的动态基因调控网络推断、转录调控和转录后调控协同作用的网络推断以及基因调控网络活性评价等,并展望了基因调控网络推断的重要研究方向。  相似文献   

10.
Annual estimates of total fertility rate and mean age of childbearing from the years 1921-80 in the US were fitted to a bivariate autoregression model incorporating regression adjustments for the effects of World War II on fertility. The time series model reduces to a transfer function model in which the total fertility rate is a function of its own past and noise, while mean age at childbearing is a function of its own past, the past of the total fertility rate, and noise. Although contemporaneous changes in mean age of childbearing tend to be negatively correlated with changes in total fertility rate, there is a tendency for adjustments in mean age to be in the same direction as changes in total fertility in the long run. The dynamic tendency in the relationship between these 2 variables is not obvious in simple graphs of these quantities. Forecasts beyond the year 1944 were found to include high standard errors and thus are considered useless as guides to the future behavior of these variables. However, other time series could be added to the model, and the judgements of demographers, economists, and sociologists could be blended with the model-based extrapolations to provide useful data.  相似文献   

11.
采用2004~2017年省际面板数据及门槛计量技术,实证分析了命令型、自愿型和经济型三类环境规制对绿色技术创新驱动产业升级的异质动态调节影响。研究发现,绿色技术创新显著驱动了国内产业升级,但绿色技术创新的产业升级效应具有明显的倒“U”型动态演化特征;环境规制在绿色技术创新驱动产业升级过程中发挥着“调控器”功能,不仅可扭转绿色技术创新对产业升级的不利影响,还有助于提升绿色技术创新的产业升级效应;绿色技术创新对产业升级的动态影响具有显著的异质环境规制调节特征,在命令型环境规制和经济型环境规制调节下均呈现正向“U”型特征,在自愿型环境规制调节下具有正向倒“U”型规律;现阶段环境规制的调节效果存在显著差异,从调控手段来看,命令型环境规制最佳、经济型环境规制次之、自愿型环境规制较弱。从空间差异来看,东部地区最明显、西部地区次之、中部地区较差。  相似文献   

12.
The historic decline in completed marital fertility has long been studied for its effects on the Demographic Transition in Europe. I applied logistic models to the actual data and test for statistical fit of the model to the data. I explain the logistic patterns in declining completed marital fertility rates assume that, as Western countries underwent diffusion of family limitation, individuals observed the behavior of others in their and adjoining cohorts. Social integration is then assumed to have lead to imitative processes in which individuals increasingly reduced their fertility in through processes of endogenous feedback. I demonstrate that a non-stationary stochastic process is able to explain the change of the distribution of the ratio of the number of the children with current hypothesis of the underlying mechanism. It is also more parsimonious and provides a good fit to the observed change of the ratio distribution of the number if children that traditional approaches have not done.  相似文献   

13.
lhtroduCtlonThe relatloDshlp bet W6W6en the economic gr OWOWth and population growth Is the one of mostimportant problems In the economic growth theorem.In the empirical analyses,the level offertility and the level ofincomeper caplta Is one of*the strongest observably negative correl砒ions,In cross-country dataIS].Constructing a mathematical model to confirm the empirical indingsIs a m叼or method In thetheoretical study、BeckerI6];GalorI7]and TaTamuraW use OLG modelto discuss this…  相似文献   

14.
The primary aim of this paper is to expose the use and the value of spatial statistical analysis in business and especially in designing economic policies in rural areas. Specifically, we aim to present under a unified framework, the use of both point and area‐based methods, in order to analyze in‐depth economic data, as well as, to drive conclusions through interpreting the analysis results. The motivating problem is related to the establishment of women‐run enterprises in a rural area of Greece. Moreover, in this article, the spatial scan statistic is successfully applied to the spatial economic data at hand, in order to detect possible clusters of small women‐run enterprises in a rural mountainous and disadvantaged region of Greece. Then, it is combined with Geographical Information System based on Local Indicator of Spatial Autocorrelation scan statistic for further exploring and interpreting the spatial patterns. The rejection of the random establishment of women‐run enterprises and the interpretation of the clustering patterns are deemed necessary, in order to assist government in designing policies for rural development. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

15.
Shipping companies are forced by the current EU regulation to set up a system for monitoring, reporting, and verification of harmful emissions from their fleet. In this regulatory background, data collected from onboard sensors can be utilized to assess the ship's operating conditions and quantify its CO2 emission levels. The standard approach for analyzing such data sets is based on summarizing the measurements obtained during a given voyage by the average value. However, this compression step may lead to significant information loss since most variables present a dynamic profile that is not well approximated by the average value only. Therefore, in this work, we test two feature‐oriented methods that are able to extract additional features, namely, profile‐driven features (PdF) and statistical pattern analysis (SPA). A real data set from a Ro‐Pax ship is then considered to test the selected methods. The data set is segregated according to the voyage distance into short, medium, and long routes. Both PdF and SPA are compared with the standard approach, and the results demonstrate the benefits of employing more systematic and informative feature‐oriented methods. For the short route, no method is able to predict CO2 emissions in a satisfactory way, whereas for the medium and long routes, regression models built using features obtained from both PdF and SPA improve their prediction performance. In particular, for the long route, the standard approach failed to provide reasonably good predictions.  相似文献   

16.
林富春  李红  金亮 《数学研究》2002,35(2):204-210
利用提升格式,构造了CDF型的双正交小波,并探讨了提升算子S的选择规律,最后给出构造实例,结果表明:这种构造方法比传统的构造方法简单、易行,而且选择不同的提升算子S,可以得到不同性质的双正交小波,充分显示出这种构造方法的实用性和广泛性。  相似文献   

17.
This paper discusses the use of comparative performance measurement by means of Data Envelopment Analysis in the context of the regulation of English and Welsh water companies. Specifically, the use of Data Envelopment Analysis to estimate potential cost savings in sewerage is discussed as it fed into the price review of water companies carried out by the regulator of water companies in 1994. The application is used as a vehicle for highlighting generic issues in terms of assessing the impact of factors on the ranking of units on performance, the insights gained from using alternative methods to assess comparative performance, and the issue of assessing comparative performance when few in number but highly complex entities are involved. The paper should prove of interest to those interested in regulation and, more generally, in the use of methods of comparative performance measurement.  相似文献   

18.
邱磊  刘小兵 《运筹与管理》2018,27(12):181-186
以网运分离的视角,基于DEA(data envelopment analysis)数据包络分析模型,运用1993~2016年相关成本与产出指标数据,对中国铁路行业路网环节的自然垄断属性进行了实证分析。结果表明:中国铁路行业路网环节在实证研究的时间段内不存在规模报酬递增,因此不具有明显的自然垄断属性。由此,中国铁路行业路网环节的政府管制需要改革,不仅包括准入和价格管制的放松,还有适度的投资管制以及质量管制的加强。  相似文献   

19.
The study of factors affecting human fertility is an important problem affording interesting statistical and computational challenges. Analyses of human fertility rates must cope with extra variability in fecundability parameters as well as a host of covariates ranging from the obvious, such as coital frequency, to the subtle, like the smoking habits of the female’s mother. In retrospective human fecundity studies, researchers ask couples the time required to conceive. This time-to-pregnancy data often exhibits digit preference bias, among other problems. We introduce computationally intensive models with sufficient flexibility to represent such bias and other causes yielding a similar lack of monotonicity in conception probabilities.  相似文献   

20.
中国电力生产业的效率:一个基于政府管制的研究视角   总被引:1,自引:0,他引:1  
通过使用数据包络分析(DEA)和Malmquist指数分析方法对中国电力生产业从1998年到2007年的技术效率和全要素生产率(TFP)进行了估算,并从效率比较以及生产率变化的角度分析了中国电力管制政策的效果。实证分析表明,中国电力产业的技术效率经历了一个先下降后上升的U型过程,地理区位、企业类型、企业性质、电力管制改革等因素对效率有着显著的影响。TFP在10年间经历了缓慢的增长,技术效率的提高解释了TFP的所有变化。从管制政策的效果来看,从1997年开始的电力管制改革对电力生产企业的技术效率产生了实质性的影响,促进了企业技术效率的提高。但是,电力管制改革对TFP的影响并不明显,特别是在促进企业的技术进步方面并没有取得明显效果。  相似文献   

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