一类变系数高阶线性齐次微分方程解的探求(英文)

本文对系数全为多项式和广义多项式的n阶线性齐次微分方程引入特征方程的概念。给出了具有指数型解的充要条件，推广了经典的常系数线性方程和著名的Euler方程的的解法，为求解变系数线性微分方程提供了有效的方法。     

非线性热传导方程u_t-Δu=D~βf(u)的Cauchy问题的整体解及渐近性

本文利用压缩映象原理及线性方程 Cauchy 问题的解的衰减性佶计,研究了一类非线性热传导方程 Cauchy 问题的整体解的存在唯一性及渐近性,得到当初值及非线性项满足一定条件之下Cauchy 问题的适当性。从而补充了文[3]的结果,首次指出了文[1]的结果是对半线性方程独有的。     

高Si/C高强度铸铁中C、Si、Si/C的作用及其选择

本文叙述了高Si/C高强度灰铸铁中碳、硅元素存在的形式及其对结晶过程的影响。试验表明,当碳当量一定时,随着Si/C的升高,初生奥氏体枝晶数量增多并且细化和强化,从而构成了强度的基础。该铸铁的强度模式应为“初生奥氏+共晶团”。本文对E型石墨存在的必然性和合理性也进行了讨论。     

一类二阶中立型时滞差分方程的振动定理

研究了一类具有变系数的二阶中立型时滞差分方程的振动性,得到了该类方程振动及差分算子△振动的一个充分条件.     

二维变系数线性微分系统的求解定理

给出二维变系数线性微分系统在已知某解的情形下求通解的公式,并直接应用此公式,导出几类二维变系数线性微分系统的通解公式.对理论和实际应用都是有益的.     

平面三次微分系统研究综述

本文首先阐明了研究E3的重要意义,然后指出E3的一般性质。奇点的分类与判定极限环线与奇异闭轨的存在性与唯一性,相对位置与代数曲线解．     

从语义学到心灵哲学： 重思对阿奎那关于理智之非物质性论证的一些批评

阿奎那关于个别感觉与普遍理性表征的理论是其对理智之非物质性论证的关键部分，但这一理论受到司各特、奥卡姆及布里丹等后来者的批评。然而，这些批评其实都不能成立。阿奎那的论证并不像罗伯特·帕斯纳奥对他的诘难中所说的那样，犯了从一个表征的语义内容推出此表征之本体论属性的“内容谬误”。此外，由布里丹本人的评论可以看出，布里丹实际上不得不接受他所批评的阿奎那论证所蕴含的主要内容。     

Problem‐ and solution‐focused characteristics of parenting support, 3 years after implementation of the solution‐focused approach: A qualitative content analysis

In recent years, solution‐focused parenting support has been developed and implemented as a promising brief and strength‐based approach. Given the fundamental differences between solution‐focused and the historically more common problem‐focused parenting support and the complexity of transforming professional practice, an actual shift towards solution‐focused parenting support can be expected to be limited up to now. However, because research into the specific communication characteristics of professional parenting support is currently lacking, no conclusion can be drawn at present. Therefore, this study aims to explore the current problem‐ and solution‐focused characteristics of parenting support in the Dutch youth healthcare (YH). In total, 15 support sessions performed by 10 public health nurses were audio recorded and transcribed verbatim. A detailed qualitative content analysis of professional communication was conducted to identify problem‐ and solution‐focused factual, expressive, relational and appealing aspects of parenting support. Problem‐focused characteristics dominated all sessions of parenting support. This study is the first to thoroughly analyse the problem‐focused and solution‐focused communication characteristics of professional parenting support using a qualitative content analysis. Parenting support practice in the Dutch YH did not shift substantially to a solution‐focused approach. More effort is required to stimulate and facilitate this professional transformation.     

Fused least absolute shrinkage and selection operator for credit scoring

Credit scoring can be defined as the set of statistical models and techniques that help financial institutions in their credit decision makings. In this paper, we consider a coarse classification method based on fused least absolute shrinkage and selection operator (LASSO) penalization. By adopting fused LASSO, one can deal continuous as well as discrete variables in a unified framework. For computational efficiency, we develop a penalization path algorithm. Through numerical examples, we compare the performances of fused LASSO and LASSO with dummy variable coding.     

Cumulative correspondence analysis using orthogonal polynomials

Taguchi's statistic has long been known to be a more appropriate measure of association of the dependence for ordinal variables compared to the Pearson chi-squared statistic. Therefore, there is some advantage in using Taguchi's statistic in the correspondence analysis context when a two-way contingency table consists at least of an ordinal categorical variable. The aim of this paper, considering the contingency table with two ordinal categorical variables, is to show a decomposition of Taguchi's index into linear, quadratic and higher-order components. This decomposition has been developed using Emerson's orthogonal polynomials. Moreover, two case studies to explain the methodology have been analyzed.