Number of Factors in Growth Curve Modeling

Basic growth curve models parameterize the mean and covariance structure of a set of repeated measures by latent factors that represent the polynomial influences of time. In practice it may be hard to choose the number of factors, i.e., the order of the polynomial. Simple calculations are proposed to estimate this order.     

木结构框架在水平荷载作用下的内力和侧移计算

借助相关曲线模型,以榫头为原形建立过渡梁单元,并以云南省传统村镇民居木结构房屋为例,计算在水平荷载作用下的内力和侧移,得出半刚性对木结构计算的重大影响。     

Stimulated Growth of Aerobic Microbes Using Calcium Peroxide

The dissolved oxygen (DO) level in groundwateris a key parameter forin situbioremediation of con-taminated groundwater. However, due to the poorcontent of DO in groundwater, aerobic microbial deg-radation is difficult to occur in natural condition. Ear-ly work on enhancedin situbioremediation deliveredoxygen to the contaminated aquiferbyspargingairin awell, but the low solubility of oxygen increased thedifficulty and expense of maintaining aerobic condi-tions in groundwater[1]. This problem …     

球面系方程及其应用

给出了五类球面系方程,并例说了球面系方程在计算、证明等中的应用。     

椭球面装饰铝板系统的设计

本文建立了椭球面上或偏离椭球面的经纬线长度、曲率半径、龙骨弯曲方向等几何参数的计算模型和方法。     

以yn=xn+1-xn为不变曲线的二次系统

证明了以yn=xn 1-xn,n∈Z为不变曲线的二次系统当n≥3或n≤1时至多存在一个极限环,结合文[1]的结论,说明了以yn=xn 1-xn,n∈Z为不变曲线的二次系统至多有一个极限环.     

Examining the impact of prior academic achievement on moral reasoning development among college students: A growth curve analysis

Moral reasoning is concerned with making decisions regarding the appropriate course of action in particular situations and has been highlighted as a critical factor that may facilitate (or impede) the effectiveness of educational programs in promoting positive outcomes. This study examined the trajectories of moral reasoning as measured by the Defining Issues Test (DIT2) for college students and to what extent there are intra-individual (within student) and inter-individual (between student) changes in moral reasoning during this developmental period. The results suggest that moral reasoning was best represented by a linear increase on the mean level and non-signi?cant variability across students. The relationship between moral reasoning and students’ prior academic attainment was also examined.     

用计算机解决数学问题

利用计算机这种现代化工具进行科学处理已越来越广泛 ,本文主要利用Office中的Excel程序解决数学中的几个实际问题 .     

关于心理测验理论模式的比较

真分数理论和项目反应理论是心理测验的两大理论模式。真分数理论主要是估计真分数和实得分数之间关系的；项目反应理论是将被试对单个测验项目的某种反应概率与此项目的一定特征联系起来，项目反应理论可以说是在真分数理论基础上的一种发展，但绝不是真分数理论，两者所建立的理论的基本假设不同，并各有其优势与不足。今天的心理测验就是在这两大理论共存的情况下，互相促进、互相补充，并在此基础之上向更合理、更完善的方向发展     

Nonlongitudinal Estimation of Growth Curve Parameters: The Cohort Growth Model

The cohort growth model (CGM) is a method for estimating the parameters of a latent growth model (LGM) based on cross-sectional data. The CGM models the interindividual differences in the growth rate, and it models how subjects’ growth rate is related to their initial status. We derive model identification for the CGM and illustrate, in a simulation study, that the CGM provides unbiased parameter estimates in most simulation conditions. Based on empirical data we compare the estimates of the CGM with the estimates of the LGM. The results were comparable for both models. Although the estimates of the (co)-variances were different, the estimates of both models led to similar conclusions on the developmental change. Finally, we discuss the advantages and limitations of the CGM, and we provide recommendations for its use in empirical research.