Revisiting the dimensionality of subjective task value: Towards clarification of competing perspectives

Expectancy-value researchers have described the components of subjective task value in multiple ways, leading to multiple competing structural representations of subjective task value data. The purpose of this study was to examine these competing multidimensional factor structures by comparing correlated factor, hierarchical, and bifactor representations of both confirmatory factor analysis and exploratory structural equation modeling (ESEM) models across three theoretical conceptualizations of subjective task value. Results indicate that, in an undergraduate life science learning context (n = 334), the best representation for subjective task value data was a bifactor ESEM model that allowed for the disentangling of general and specific variance of general subjective task value, specific value beliefs, and specific costs. Full measurement invariance of the retained structure across continuing generation and first-generation students was found, and no differential item functioning was found across gender. General subjective task value and specific opportunity cost significantly and positively predicted achievement and specific utility value significantly and negatively predicted achievement, providing support for the criterion-related validity of the general and specific factors for predicting achievement outcomes.     

线性齐次向量差分方程的共轭方程

本文给出了线性齐次向量差分方程（差分系统）的共轭方程的定义和性质．得出了一些独立的结论。     

数学问题研究二则

本文提出了曲面是旋转面的一个充要条件及圆和单位等轴双曲线参数方程的另一种形式。     

Cross-National Validation of the What is Happening in this Class? (WIHIC) Questionnaire using Confirmatory Factor Analysis

Learning Environments Research - The What Is Happening In this Class? (WIHIC) questionnaire was validated cross-nationally using a sample of 3980 high school students from Australia, the UK and...     

CAD中关于表格、线图及离散数据的处理方法

本就CAD过程中经常遇到的表格数据、线图数据、离散数据的计算机处理方法作了简单介绍，希望对CAD工作有所帮助。     

智慧服务情境下图情服务人员学习敏锐度的实证研究

[目的/意义]以学习敏锐度为切入点,探究图情人员在智慧服务这一陌生的新情境下,如何迅速提升自我素质和潜能从而更有效地胜任和完成新工作的相关问题,为未来更好地开展智慧服务提供参考和借鉴。[方法/过程]通过收集对国内"双一流"高校的189份调查问卷,运用结构方程的分析方法,深入研究智慧服务情境下图情服务人员的学习敏锐度,包括：①学习敏锐度测量的关键组成要素是否有效;②这些关键组成要素与服务创新意愿、服务成效之间的相关关系。[结果/结论]研究发现：智慧服务情境下,图情服务人员的学习敏锐度由自我洞察、人际敏锐、变革意愿和环境敏感四大关键因素组成,它们分别与服务创新意愿、服务成效呈现显著的正向相关关系;同时,服务创新意愿与服务成效之间呈现显著的正向相关关系。最后,针对图情服务的管理进行深入探讨,并提出相应对策建议。     

再证微分中值定理

通过分析要证的结论，找到一个满足罗尔定理全部条件的新辅助函数，使拉格朗日和柯西微分中值定理的证明变得更为简单明了。     

关于高阶中立型非线性时滞微分方程振动及非振动性一文的一点注记

实质性地改进了“高阶中立型非线性时滞微分方程振动及非振动性一文中定理的主要条件。     

Local Harnack Inequality for Porous Medium Equation with Convection

In this paper we consider the following problem where the summation convention is used. We call the equation as porous medium equation with convection. Let u = u(x,t) be a continuous weak solution of the equation in Rn × (0 ,T] for some T> 0. Then we can establish BCP estimates and the intrinsic Harnack inequality for the solution of the equation just as the standard equation discussed by other authors previously. This work lay a main foundation of studying other properties of this problem further.     

解抛物型方程的一族高精度差分格式

用待定参数法对一维抛物型方程构造了一个双参数高精度恒稳定的隐式差分格式，截断误差达O（△t^3 △x^4)，可用追赶法求解。