供应链中基于信息更新的订货时间及价格联合决策研究

文章考虑在信息可更新的情况下,由一个制造商和一个零售商组成的供应链中订货时间及价格的联合决策问题.在模型中,制造商为零售商提供多次订货时间选择及相应的订货价格,而零售商可以在销售季节开始前自由选择订货时间并享受相应的价格.文章以不同订货时间对信息更新程度的影响为着眼点,将订货时间作为内生决策变量,突破了已有文献中仅限于两次订货时间选择的局限,分别从集中决策和分散决策两个角度建立供应链节点企业的利润模型,并在分散决策情况下引入收益共享契约,寻找帕累托改进.最后通过数值试验证明了该模型的有效性.     

关于高职院校教育科研的现状调查与对策研究

针对当前高职院校的教育科研状况进行分析,指出了人们对教育科研的认识偏差,以及管理机制不健全,组织结构混乱,制度流于形式,教育科研缺乏针对性,重形式、轻效果现象突出等问题。提出提高思想认识,构建教育科研新机制,打造＂科研兴校＂优良环境,应是高等职业教育健康发展的重要举措。     

新时期我国农村公共产品供给问题探析

农村公共产品是农民增收,农业和农村得以发展的前提保证。但目前我国农村公共产品供给存在着供给总量不足,供给效能低下和供给主体错位等问题。当然,导致农村公共产品供给困难的原因是多方面的,文章主要从两方面来分析,并根据这两方面原因提出了加大对农村公共产品的供给,建立农民需求表达机制,实现供给主体多元化和完善相关监督机制等解决途径。     

“大学生上网“负面影响分析及消解对策

网络在给大学生带来便捷的同时,也带来了一定的负面影响.大学生溺网、网恋、上不健康网站以及由此引起的社会治安问题等已经引起了社会各界的普遍关注.要消除"大学生上网"产生的负面影响,高校应从提高学生网络素质,培养大学生网上自律,构建高校网络文化主阵地等方面入,引导大学生正确对待网络、做到健康上网.     

我国市场经济条件下的福利最大化问题

本文经初步研究得出在我国社会主义市场经济中,在一定的条件下,既可使社会福利达到最大,又可使消费者的个人效用达到最优的结论。建立了相应的数学模型,给出了相应的经济含义及分析。并指出其社会福利最大点将优于完全竞争条件下的福利最大点。     

Short-Term Dermal Absorption and Penetration of Chemicals from Aqueous Solutions: Theory and Experiment

Dermal penetration of organic chemical-contaminated water from showering and bathing scenarios is a concern of regulatory agencies that have been tasked with determining safe exposure levels. During household showering and bathing, nearly the entire surface area of the body is exposed for short periods of time (5-15 minutes). The primary means of predicting body burden during brief exposures is to estimate total chemical penetrated from the steady-state penetration rate using a skin permeability coefficient. A variety of approaches has been recommended to estimate "body burden." The purpose of this investigation was to collect experimental data from short-term exposures to an organic chemical (dibromomethane [DBM]) in aqueous solution so that methods for estimating body burden could be compared. Rat skins were exposed in vitro to saturated aqueous solutions of DBM for 20 minutes and the amount of chemical in the receptor solution and the skin was analyzed. The total DBM mass in the receptor solution and the skin was taken to represent an in vivo body burden. These results were compared with the estimates of penetration from steady-state calculations, square root of time calculations, and a biologically based mathematical model. Results indicated that the amount of chemical in the skin and its fate during short exposures is important. The square root of time approach predicted total amount of chemical absorbed and penetrated better than did the steady-state approach. The biologically based mathematical model accurately predicted total body burden and could be used to distinguish between the amount of chemical in the skin and the amount of chemical that penetrated through the skin, which would be useful for understanding local toxicity.     

CET写作能力提高的必要性及途径

为了增强中外语言交际能力,提高大学生ＣＥＴ写作能力十分必要,可是ＣＥＴ写作一直是众多大学生的弱项。鉴于此,本文通过对问卷调查结果及学生写作中存在的句型单一、成份缺失与布局不合理等主要问题的分析,提出“火花式训练＋十句训练法”,“名言警句＋主题句”等一系列改进方法及其途径。     

Recurrence relations between product moments of order statistics

A general result for obtaining recurrence relations between product moments of order statistics is established and this result is used to determine the recurrence relations between product moments of some doubly truncated distributions. The examples considered are Weibull, exponential, Pareto, power function and Cauchy distributions.     

CANONICAL VARIATE ANALYSIS—A GENERAL MODEL FORMULATION

A general model, specifying the population means as a function of the population canonical vectors, provides a natural basis for considering many aspects of canonical variate analysis. These aspects include: estimation for elliptical densities, and robust estimation; estimation of missing values; adequacy of hypothetical variables; regression in dummy variable space; and comparison of solutions.     

移动终端“深阅读”的现实困境与突围路径

随着各种移动终端的普及,数字阅读已进入移动时代.但是,移动阅读所呈现出的碎片化浅显化特征,明显与"深阅读"的要求有所不同.本文认为,读者阅读习惯改变、优质数字内容相对稀缺和新娱乐交往方式的冲击是导致移动"深阅读"出现当前发展困境的三个主要因素,要推动移动阅读不断由浅入深,可尝试从优质数字内容建设、优化移动阅读体验、培养良好数字阅读习惯和加大移动阅读推广力度等四个方面入手,逐步改善移动阅读碎片化浅显化的现状.