椭圆上弧微分的变化规律及其应用

文章对以极角为参数的椭圆参数方程展开讨论,通过对弧微分变化规律的分析,给出了椭圆弧长的估计及其相关条件,使得这种估计的几何意义更为显著;同时将所得的结果应用于刻划椭圆上质点运动的线速度变化过程。     

不可压磁流体方程在柱坐标下的表示及其基本能量估计

在考虑方程解的适定性时,解有有限能量总是一个最基本要求。因此,对方程做基本能量估计是非常有必要的,也是考虑解的适定性的前提。本文给出了磁流体力学方程在柱对称条件下的解的基本能量估计,这为后续的解的存在唯一性,正则性等,提供了一个保障。首先运用微积分的知识,将直角坐标系下的梯度算子和拉普拉斯算子换算成柱坐标系下的情形,进而求得柱坐标系下的磁流体力学方程表达式,而后求该方程在无旋情形(所有变量关于角变量是固定的)的基本能量估计。     

投资项目风险多角度估计方法研究

对于项目风险的准确估计一直是风险管理研究较为关注的课题,然而很多研究都是从少数两、三个角度对项目风险进行基本描述,似乎并不全面。本文根据风险的一些特点,提出从风险发生概率、风险损失、风险控制成本和风险影响范围四个方面对风险进行多角度估计,以期能对项目风险进行较为全面的描述。     

关于平行平均曲率向量的子流形(英文)

研究了空间形中具有平行平均曲率向量的子流形上共形度量的数量曲率的上界和超曲面的稳定性.     

论发展性学生评价

发展性学生评价更加关注学生的明天，用多元化、多视角的评价促进学生各方面发展，以生活化、情景化的评价为学生未来的发展打好基础。相对于传统学生评价，我们不难看出它的优势所在。在育人过程中，采用这样的发展性学生评价，将对学生发展和我们的教育事业都有很大帮助。     

Brief Research Report: Bayesian Versus REML Estimations With Noninformative Priors in Multilevel Single-Case Data

Abstract

Recently, researchers have used multilevel models for estimating intervention effects in single-case experiments that include replications across participants (e.g., multiple baseline designs) or for combining results across multiple single-case studies. Researchers estimating these multilevel models have primarily relied on restricted maximum likelihood (REML) techniques, but Bayesian approaches have also been suggested. The purpose of this Monte Carlo simulation study was to examine the impact of estimation method (REML versus Bayesian with noninformative priors) on the estimation of treatment effects (relative bias, root mean square error) and on the inferences about those effects (interval coverage) for autocorrelated multiple-baseline data. Simulated conditions varied with regard to the number of participants, series length, and distribution of the variance within and across participants. REML and Bayesian estimation led to estimates of the fixed effects that showed little to no bias but that differentially impacted the inferences about the fixed effects and the estimates of the variances. Implications for applied researchers and methodologists are discussed.     

Unnatural Disasters: Two Calculus Projects for Instructors Teaching Mathematics for Social Justice

Abstract

We provide context and motivation for an instructor to use real-life examples in the calculus classroom. To this end we describe two specific project ideas, one related to the devastating impact of methylmercury fungicide in a grain seed supply and the other to a catastrophic methane leak. By using calculus in contexts that have social justice implications, we hope to empower students to reason for themselves, to use mathematics as a powerful tool to deepen their understanding of the world, and ultimately, to effectively confront the challenges society faces.     

一种新的广告效果评估方法——熵权双基点法

结合实例介绍了一种新的广告效果评估方法——熵权双基点法 .运用这一方法对各项信息进行无量纲化处理 ,计算出各项信息的权重 ,获得广告效果的准确评价 ,从而为企业选择符合广告目的的媒体组合提供科学参考     

Application of the Bayes’ theory to the failure rate evaluation of electrical apparatus

The Weibull distribution has been widely used in reliability fields. A mixed Weibull distribution represents a popu- lation that consists of several Weibull subpopulations. In this paper, a new approach which combines the least-squares method with Bayes’ theorem, takes advantage of the parameter estimation for single Weibull distribution is developed to estimate the pa- rameters of each subpopulation. The estimates given by this paper also satisfy the maximum likelihood equation. The estimates of the failure rate of the mixed Weibull population are given. An actual test data is computed by using the proposed method. The Kolmogorov-Smirnov goodness-of-fit test turns out that the proposed method yields more accurate result.     

高分辨率遥感影像在林业应用中存在的问题与思考

高分辨率遥感影像的出现，给林业遥感带来前所未有的机遇,但是高分辨率遥感影像在林业领域中的应用面临诸多问题,如数据源的价格偏高、图像阴影无法去除、树种识别困难和森林蓄积量估测精度不高等,提出了建立主要树种的波谱数据库，采用基于多特征的面向对象的分类技术，提高高分辨率影像在林业中的应用水平等建议。