手动爬楼梯轮椅的运动过程分析

对一种手动爬楼梯轮椅的运动过程进行了分析。在各部件不与楼梯台阶相干涉的条件下，计算出了车辆质心位置的座标值，并依此绘出质心的位移轨迹曲线。计算了轮椅在上爬楼梯时运动期的中间段质心的速度、加速度以及人的操纵力值。为进一步进行动力学分析和轮椅的改进设计提供了依据。     

Unspanned Macroeconomic Factors in the Yield Curve

In this article, we extract common factors from a cross-section of U.S. macro-variables and Treasury zero-coupon yields. We find that two macroeconomic factors have an important predictive content for government bond yields and excess returns. These factors are not spanned by the cross-section of yields and are well proxied by economic growth and real interest rates.     

Bayesian estimation and influence diagnostics of generalized partially linear mixed-effects models for longitudinal data

This paper develops a Bayesian approach to obtain the joint estimates of unknown parameters, nonparametric functions and random effects in generalized partially linear mixed models (GPLMMs), and presents three case deletion influence measures to identify influential observations based on the φ-divergence, Cook's posterior mean distance and Cook's posterior mode distance of parameters. Fisher's iterative scoring algorithm is developed to evaluate the posterior modes of parameters in GPLMMs. The first-order approximation to Cook's posterior mode distance is presented. The computationally feasible formulae for the φ-divergence diagnostic and Cook's posterior mean distance are given. Several simulation studies and an example are presented to illustrate our proposed methodologies.     

Investigating impacts of complex sampling on latent growth curve modelling

We investigate the impacts of complex sampling on point and standard error estimates in latent growth curve modelling of survey data. Methodological issues are illustrated with empirical evidence from the analysis of longitudinal data on life satisfaction trajectories using data from the British Household Panel Survey, a national representative survey in Great Britain. A multi-process second-order latent growth curve model with conditional linear growth is used to study variation in the two perceived life satisfaction latent factors considered. The benefits of accounting for the complex survey design are considered, including obtaining unbiased both point and standard error estimates, and therefore correctly specified confidence intervals and statistical tests. We conclude that, even for the rather elaborated longitudinal data models that were considered, estimation procedures are affected by variance-inflating impacts of complex sampling.     

Accuracy of approximate progressively censored reliability sampling plans for exponential models

Reliability sampling plans provide an efficient method to determine the acceptability of a product based upon the lifelengths of some test units. Usually, they depend on the producer and consumer’s quality requirements and do not admit closed form solutions. Acceptance sampling plans for one- and two-parameter exponential lifetime models, derived by approximating the operating characteristic curve, are presented in this paper. The accuracy of these approximate plans, which are explicitly expressible and valid for failure and progressive censoring, is assessed. The approximation proposed in the one-parameter case is found to be practically exact. Explicit lower and upper bounds on the smallest sample size are given in the two-parameter case. Some additional advantages are also pointed out.     

使用PC1D 5.9模拟高效单晶硅太阳能电池

介绍了使用PC1D 5.9软件模拟高效单晶硅太阳能电池的方法。通过建立太阳能电池的结构模型和参数模型,在模拟的电池测试环境下,仿真得到太阳能电池的电压-电流曲线和量子效率曲线,并根据太阳能电池的理论,计算填充因子和转换效率的值。     

Evaluation of the parameters of su by rational fractions

A rational fraction approximation is given for a function of one of the parameters defining Johnson's S_UError assessment for a segment of the domain of validity shows remarkable accuracy.     

Multivariate outliers and decompositions of mahalanobis distance

Two decompositions of the Mahalanobis distance are considered. These decompositions help to explain some reasons for the outlyingness of multivari- ate observations. They also provide a graphical tool for identifying outliers including those that have a large influence on the multiple correlation coefficient, Illustrative examples are given.     

The Pursuit of Continuous Improvement in the Field of Intergenerational Relationships: The Discipline of the Second Curve

This article presents a case for the field of intergenerational relationships to embrace the challenges associated with progressing its reputation, boundaries, and potential in the twenty-first century. The concept of the Sigmoid curve based upon curvilinear logic and the discipline of the second curve is introduced as a means of understanding how individuals, organizations, and institutions need to deal with the challenge of constant renewal as a consequence of rapid social change. The field of intergenerational relationships is challenged to align itself with the discipline of the second curve by (1) improving the impact of research through knowledge-based transfer and (2) exploring new fields of inquiry in the interest of maintaining and advancing relevance and legitimacy.