时间模上非线性两-点边值问题的正解

变系数模型是由古典的线性模型发展而来,它们可以很好地检验函数系数随着协变量的变化程度.文章用PLR提出了变系数模型误差方差的估计,并研究了它的渐近正态性,进一步用一个模拟例子来说明估计的结果是有效的.     

变系数回归模型的参数估计

讨论了变系数回归模型中变系数的加权最小二乘估计和变系数的加权可估函数的线性估计的最优性;推广了Gauss-Markov定理;并且构造出参数σ2的估计量.     

变系数联立模型的变窗宽局部线性两阶段最小二乘估计

研究了变系数联立模型的参数的估计问题,利用变窗宽局部线性两阶段最小二乘法对变系数联立模型的系数进行了估计,进而得到了估计量的大样本性质。     

一类新的变系数模型的积分估计

该文从实际出发给出了一类实用范围较广的变系数模型,它们的系数函数的自变量(也称光滑变量)不完全一致.首先,使用局部线性方法给出模型的系数函数的初始估计;然后使用积分方法,给出它们的积分估计;进一步,研究这些积分估计的渐近正态性.模拟结果说明该估计方法的有效性.     

半变系数模型的估计及性质

半变系数模型在统计中具有重要的应用,本文时该模型的常数系数,采用局部多项式估计方法和平均方法,给出了它的估计,对于函数系数的估计通过应用常数系数的估计,采用局部多项式估计方法给出其估计,并给出估计的渐近正态性和证明．     

固定效应部分线性变系数面板数据模型的估计

在部分线性变系数面板数据模型基础上,引入了不可观测的固定效应,研究了模型的估计问题。首先引入虚拟变量消除固定效应带来的影响,然后应用轮廓最小二乘估计法对模型中的参数进行估计,接着对模型中的变系数基于B样条基函数展开的方法逼近,再对模型中的未知系数函数进行估计,最后通过Monte Carlo模拟方法验证了当解释变量取自于不同分布时,模型的估计在有限样本下具有良好的估计效果。     

变系数EV模型系数参数的两步核估计结果的比较

利用核函数法和广义最小二乘法对一般变系数EV模型给出了参数的两步估计,并从误差方差的角度对其结果进行了比较.     

消费、投资和出口对我国经济增长影响的状态空间分析——兼与马学俊等商榷

投资、消费和出口对经济增长的影响是经济研究的基础性问题,近年来,一个新的研究点在于三者对经济增长的影响是如何随时间变化的.建立了基于状态空间方法的变系数模型,克服了用局部多项式方法估计变系数模型的不足,并分析了1978-2013年我国投资、消费、出口与经济增长的关系.结果表明,改革开放后,投资和出口对经济增长的拉动作用均呈现先升后降的趋势,消费对经济的拉动作用呈现上升趋势,且已成为推动经济发展的最大动力.总的来看,我国进行供给侧改革和引导居民进行消费的措施符合当前经济发展的要求.     

线性模型参数的最优同变估计

本文讨论了线性模型当随机误差为位置分布族时参数的同变估计,并给出了最优同变估计(MREE),结果表明线性模型参数的最优同变估计与最小二乘估计是一致的.     

一类新的变系数模型的积分估计

该文从实际出发给出了一类实用范围较广的变系数模型，它们的系数函数的自变量（也称光滑变量）不完全一致．首先，使用局部线性方法给出模型的系数函数的初始估计；然后使用积分方法，给出它们的积分估计；进一步，研究这些积分估计的渐近正态性．模拟结果说明该估计方法的有效性．     

Detecting Unobserved Heterogeneity in Latent Growth Curve Models

Growth mixture models combine latent growth curve models and finite mixture models to examine the existence of latent classes that follow distinct developmental patterns. Analyses based on these models are becoming quite common in social and behavioral science research because of recent advances in computing, the availability of specialized statistical programs, and the ease of programming. In this article, we show how mixture models can be fit to examine the presence of multiple latent classes by algorithmically grouping or clustering individuals who follow the same estimated growth trajectory based on an evaluation of individual case residuals. The approach is illustrated using empirical longitudinal data along with an easy to use computerized implementation.     

应力状态系数模型对中厚板轧制压力预报精度影响研究

建立中厚板轧制压力计算模型,选取不同的应力状态系数模型对轧制压力进行预报,分析应力状态系数模型对轧制力预报精度的影响。结果表明：应力状态系数模型对轧制压力预报精度存在影响,当轧制较厚板时影响较大;中厚板轧制时,相对其他应力状态系数模型,采用模型Ⅱ计算,精度相对稳定,误差相对较小。     

量子化学参数用于脂肪酮类化合物logP的QSPR研究

采用了Chemoffice 6．0中MOPAC-AMl量子化学法计算了16种脂肪酮化合物的7种量子化学参数,其中取全部化合物作为样本集对LogP进行多元逐步回归分析,得到最佳方程,经自由度校正的回归系数R=0.998,并通过“jackknife”法中逐一抽取法进行模型检验,验证了该模型具有很好的稳定性,平均残差仅为0.05个对数单位,小于文献值,具有良好的预测能力。     

线性结构关系EV模型中参数的可估性分析

从线性回归模型中参数的可估性出发 ,研究了常系数和变系数线性结构关系EV模型中参数可估的条件 .这一条件是很一般的 .     

Ratings of usability of didactic models: a comparative case study in Croatia and Germany

The study refers to the unfavourable reputation and status of general didactics as well as its decreasing importance in teacher education. This is a result of poor performance achieved in international tests by students. They score low on knowledge and arguments, and empirical studies indicate that didactic models are useless. In view of the above problem, the aim of this article is to examine the validity of the argument that didactic models are useless. It is necessary to examine if general didactics are being in an unfavourable position along with its possible successors in the international context. In order to achieve that, we conducted an empirical study into the usability of didactic models for lesson planning in Croatia and compared it with the results obtained in previous research in Germany. The term usability means the advantages of theory in practice. On the basis of the results of the empirical study, we concluded that didactic models are not generally unusable. Additionally, they are different according to their usability. These results open a path for further research on this topic in the international context.     

《状态自我宽恕量表》在大学生群体中的修订

目的：在大学生群体中修订状态自我宽恕量表（SSFS）,考察其心理测量学指标。方法：对392名在校大学生进行测查,采用探索性和验证性因素分析等方法考察该量表的信度和效度。结果：修订后的量表有两个维度,验证性因素分析结果显示,SSFS的两因素结构拟合较好。SSFS的内部一致性信度为0．750,重测信度为0．623。SSFS的效标关联效度良好。结论：修订后的SSFS具有较好的心理测量学属性,可作为测量大学生状态自我宽恕的工具。     

工程力学课程体系与内容的改革与实践

根据高职院校的特点,对材料力学基本变形部分的内容编排做了大幅度的调整;提出了根据载荷图直接绘制轴力图、扭矩图的方法,和教材中利用载荷集度与内力之间的微分关系画剪力图、弯矩图形成有机的统一;尝试了启发式教学、列表法教学和口诀法教学;并采用多种评价方式对学生的学习情况进行综合评定。     

抗肺结核新试剂硝基呋喃铵类化合物毒性的COMFA研究

应用比较分子力场法(COMFA)研究一系列硝基呋喃铵类化合物对毒性的三维定量构效关系,为进一步药物设计提供理论依据.方法和结果:在研究的29个化合物中,用比较分子力场法得到一个COMFA模型,交叉验证系数为q2=0.538,具有较高的预测能力及合理性,非交叉验证模型相关系数分别为r2=0.939,标准偏差SE=2.22,F=46.516;结论:此模型对设计和预测低毒性的硝基呋喃铵类化合物有一定可靠性.     

Generalized Linear Factor Score Regression: A Comparison of Four Methods

Factor score regression has recently received growing interest as an alternative for structural equation modeling. However, many applications are left without guidance because of the focus on normally distributed outcomes in the literature. We perform a simulation study to examine how a selection of factor scoring methods compare when estimating regression coefficients in generalized linear factor score regression. The current study evaluates the regression method and the correlation-preserving method as well as two sum score methods in ordinary, logistic, and Poisson factor score regression. Our results show that scoring method performance can differ notably across the considered regression models. In addition, the results indicate that the choice of scoring method can substantially influence research conclusions. The regression method generally performs the best in terms of coefficient and standard error bias, accuracy, and empirical Type I error rates. Moreover, the regression method and the correlation-preserving method mostly outperform the sum score methods.     

Correlated Errors in True Score Models and Their Effect on Coefficient Alpha

It is well known that coefficient alpha is an estimate of reliability if its underlying assumptions are met and that it is a lower-bound estimate if the assumption of essential tau equivalency is violated. Very little literature addresses the assumption of uncorrelated errors among items and the effect of violating this assumption on alpha. True score models are proposed that can account for correlated errors. These models allow random measurement errors on earlier items to affect directly or indirectly scores on later items. Coefficient alpha may yield spuriously high estimates of reliability if these true score models reflect item responding. In practice, it is important to differentiate these models from models in which the errors are correlated because 1 or more factors have been left unspecified. If the latter model is an accurate representation of item responding, the assumption of essential tau equivalency is violated and alpha is a lower-bound estimate of reliability.