Measurement of Mass Difusivity of Moist Porous Media under the Influence of Forced Convection at Sur

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基于运城学院工科学生专业实习的就业力研究

二本院校大学生就业难的问题日益受到社会各界的关注。本研究通过调研运城学院工科类学生专业实习项目运作基本情况,探索分析运城学院工科学生的专业实习实际效果影响因素。研究表明,学生的家庭情况、对专业实习的认知、人际交往能力对实习效果影响显著,学生性别、政治面貌、解决问题能力、专业知识水平、以往社会实践情况对专业实习效果影响不显著。在此基础上详细介绍各影响显著因素与实际效果相关程度,构建相应的数学模型,并针对目前专业实习应该关注的因素及存在的问题提出相应的意见建议。     

Bayesian Quantile Structural Equation Models

Structural equation modeling is a common multivariate technique for the assessment of the interrelationships among latent variables. Structural equation models have been extensively applied to behavioral, medical, and social sciences. Basic structural equation models consist of a measurement equation for characterizing latent variables through multiple observed variables and a mean regression-type structural equation for investigating how explanatory latent variables influence outcomes of interest. However, the conventional structural equation does not provide a comprehensive analysis of the relationship between latent variables. In this article, we introduce the quantile regression method into structural equation models to assess the conditional quantile of the outcome latent variable given the explanatory latent variables and covariates. The estimation is conducted in a Bayesian framework with Markov Chain Monte Carlo algorithm. The posterior inference is performed with the help of asymmetric Laplace distribution. A simulation shows that the proposed method performs satisfactorily. An application to a study of chronic kidney disease is presented.     

A family of quasi-cubic blended splines and applications

INTRODUCTION Bézier curves and uniform B-spline curves are powerful tools for constructing free form curves and surfaces (FFC/FFS). But they cannot represent the arcs, hyperbola, sphere, cylinders and other transcendental curves and surfaces exactly. In order to avoid the in- conveniences, many bases are presented in other new spaces (Zhang, 1996; Pe?a, 1997; Walz, 1997; Sánchez-Reyes, 1998; Mainar et al., 2001). Note that, these existing methods can deal with both polynomial curve…     

Deformation Behavior of Hot Isostatic Pressing FGH96 Superalloy

The deformation behavior of hot isostatic pressing (HIP) FGH96 superalloy was characterized in the temperature range of 1 000-1 100℃and strain rate range of 0.001-0.1s-1 using hot compression testing. The flow curves of HIP FGH96 superalloy during hot deformation was analyzed systematically. The results show that deformation temperature, strain rate and strain are the main influence factors on flow stress of HIP FGH96 superalloy during hot deformation. The flow stress displays a peak at a critical strain and then decreases with further increase in strain. For a given strain, the flow stress decreases with the increase of deformation temperature, and increases with the increase of strain rate. A mathematical model of these flow curves was established through regression analysis and taking the strain as a modification factor. The calculated stress values agree well with the experimental values.     

Handling missing data: analysis of a challenging data set using multiple imputation

Missing data is endemic in much educational research. However, practices such as step-wise regression common in the educational research literature have been shown to be dangerous when significant data are missing, and multiple imputation (MI) is generally recommended by statisticians. In this paper, we provide a review of these advances and their implications for educational research. We illustrate the issues with an educational, longitudinal survey in which missing data was significant, but for which we were able to collect much of these missing data through subsequent data collection. We thus compare methods, that is, step-wise regression (basically ignoring the missing data) and MI models, with the model from the actual enhanced sample. The value of MI is discussed and the risks involved in ignoring missing data are considered. Implications for research practice are discussed.     

Achievement goals and classroom goal structures: Do they need to match?

Abstract

It is often assumed that students’ personal achievement goals are most beneficial when they match the goal structures of the classroom, but interaction between achievement goals and goal structures is not well researched. In this study, we aim at providing a nuanced picture of the direct, interaction, and nonlinear effects of achievement goals and goal structures on test performance and autonomous motivation. We used multiple linear regressions, including interaction and quadratic terms, in combination with response surface methodology to analyze questionnaire data from students in Grades 6-10. We found no evidence for a general match effect, and only weak indications of interactions between achievement goals and goal structures. Thus, the match between classroom goal structures and students’ personal goals may be less important for students’ motivation and achievement than previously assumed. Still, based on our results we recommend a focus on mastery structures in the classroom.     

浅谈教育的生活回归

教育与生活既辩证又统一,二者互为制约又互为意义.探讨教育回归生活对促进社会和学生个体的发展,推动基础教育深化改革,实施素质教育具有深远的意义.     

中国科技与高等教育相关性数学模型的建立与分析

本文采用1995～2002年中国科技与高等教育有关统计数据，按照一定的指标体系，通过一定信度的数学表述，借助回归分析建立了它们之间的回归方程，确立了它们的相关关系和发展趋势。     

计算机在一元回归分析中的应用

探讨了利用计算机进行一元回归分析的基本方法，设计了求一元回归预测模型的算法，并用QBASIC语言编写计算机程序。