企业的采购市场细分

市场细分是市场营销学概念,将其应用于企业的物资采购市场活动中,是一个很值得探讨的理论问题和实践问题。     

多复变数的单值性定理

本主要给出了多复变数的单值性的一个定理。     

An approach for the capture of context-dependent document relationships extracted from Bayesian analysis of users' interactions with information

A number of technologies exist which enable the unobtrusive capture of computer interface interactions in the background of a user's working environment. The resulting data can be used in a variety of ways to model aspects of search activity and the general use of electronic documents in normal working routines. In this paper we present an approach for using captured data to identify relationships between documents used by an individual or group, representing their value in a given context—that may relate to specific information need or activity. The approach employs the use of a naïve Bayesian classifier to evaluate possible relationships that are derived implicitly from the data. It is intended that the relationships established be stored within an information retrieval (IR) system to aid in the retrieval of related documents where future users arrive at a similar context. In the evaluation of the approach over 70 hours of data from computer users in industrial and academic settings are collected to assess its overall feasibility. The results indicate that the approach provides a useful method for the establishment of identifiable relationships between documents based on the context of their usage, rather than their content.     

关于一类弱奇性Wendroff型积分不等式的注记

给出了一类弱奇性Wendroff型积分不等式解的估计,所得结果推广了过去关于非线性弱奇性Wendroff型积分不等式的相关结果,并将结果应用到研究微分方程解的有界性中.     

后现代语境下高校青年教师的文化生态构建与专业发展探析——以外语教师为例

青年教师是高校师资的生力军,也是高校可持续发展的重要因素.后现代语境下,教师发展走向了多元化、去中心化的趋势,不再局限于传统的外化培训.在这样的形势下,高校青年教师需要多维、自主、内生的专业发展范式.本文以青年外语教师为例,对后现代语境下青年教师和高校应当如何有效作为,构建教师专业发展的文化生态,以及如何推动高校青年教师发展的策略进行了探讨.     

Graphical Representation of Missing Data Problems

Rubin’s classic missingness mechanisms are central to handling missing data and minimizing biases that can arise due to missingness. However, the formulaic expressions that posit certain independencies among missing and observed data are difficult to grasp. As a result, applied researchers often rely on informal translations of these assumptions. We present a graphical representation of missing data mechanism, formalized in Mohan, Pearl, and Tian (2013). We show that graphical models provide a tool for comprehending, encoding, and communicating assumptions about the missingness process. Furthermore, we demonstrate on several examples how graph-theoretical criteria can determine if biases due to missing data might emerge in some estimates of interests and which auxiliary variables are needed to control for such biases, given assumptions about the missingness process.     

Book review

Analyzing social & political change: A casebook of methods. Angela Dale and Richard B. Davies (Eds.), Thousand Oaks, CA: Sage, 1994, x+229 pages.     

Variables del proceso de enseñanza-aprendizaje del lenguaje escrito en los primeros niveles de la E.G.B.

Se revisan y comparan aquí las características del método natural-global de Freinet y se sugiere su convergencia con las que se deducen de la psicología cognitiva para la enseñanza de la lectoescritura. A partir de ahí se propone una secuencia determinada y se dan una serie de recomendaciones para abordar con éxito la enseñanza de la lectura.     

Contextual variables associated with differences in educational performance between European Union countries / Variables contextuales asociadas a las diferencias de rendimiento educativo entre los países de la Unión Europea

Abstract

Extensive literature exists which shows the relation between academic performance and other variables of a contextual nature. A secondary analysis of the results corresponding to performance in PISA 2015 has enabled us to classify European Union countries into two different levels. The degree of relation between performance and contextual variables such as socioeconomic level, schooling indicators, resources allocated to education and organizational culture and school governance has also been studied at a national level. Subsequently, after selecting the variables that correlate the most with performance, the effects of the contextual variables on the differences of countries with high and low performance have been measured using a logistic regression model. Results show the role of some of the variables considered, with the economic level of the country standing out in particular, as well as parental involvement in decision-making. By way of conclusion, a series of recommendations are formulated to advance towards improvements in performance and to achieve educational convergence among EU countries.     

关于会议筹备的优化模型

随着市场经济的不断发展,各种新兴行业也在悄然兴起,会议服务公司通过提供预定宾馆客房、租借会议室及租用客车接送代表等服务,让顾客觉得经济、方便且满意度较高。同时,会议服务公司也需要从公司的经济利益和社会声誉等诸多因素来统筹安排。本文用数学建模的方法对会议筹备问题进行了分析和研究,考虑到影响会议筹备的因素,在确保会议正常召开及参会人员满意的前提下,以筹备组支付最小费用为目标,建立了会议筹备的优化模型。