Discrete Population Models: Why They Belong in a Differential Equations Course

We make a case for including difference equations, in particular the discrete logistic equation, in basic differential equations courses. Contrasting the behavior of discrete and continuous models enriches students’ understanding of both modeling and differential equations. To facilitate sharing discrete population models with students, some materials including class handouts and an “exploratory” computer assignment are provided.     

创新军队院校后勤经费财务保障机制

军队院校后勤经费财务保障机制创新,既是社会主义市场经济深入发展的要求,也是中国特色新军事变革的需要.创新军队院校后勤经费财务保障机制,要树立现代金融意识,针对军队院校后勤经费财务保障的主要问题,引入市场机制进行制度设计和机制创新,在后勤社会化中完善财务管理,提高后勤经费使用效益,促进军队院校又好又快发展.     

浅析电力调度数据网第二平面建设

介绍了电力调度数据网现状,分析了电力调度数据网第二平面总体网络结构,技术要求,主要业务,网络安全控制方案等,提出了电力调度数据网第二平面建设方案及业务系统的接入方式。     

基于路网的动态配送系统软件开发与设计

配送车辆优化调度问题是物流系统中的一个重要环节,本软件借助VB语言,在分析静态配送的基础上,针对不断变化的市场需求,建立动态的物流配送模型,在生成路网的平台上,通过研究物流配送货物过程中路径、车辆选择的问题,提出对物流配送最优路径的动态选择方案,提高物流配送效率,满足客户需求,更符合实际。     

Logistic regression for prediction and diagnosis of bacterial regrowth in water distribution system

This paper focuses on the quantitative expression of bacterial regrowth in water distribution system. Considering public health risks of bacterial regrowth, the experiment was performed on a distribution system of selected area. Physical, chemical, and microbiological parameters such as turbidity, temperature, residual chlorine and pH were measured over a three-month period and correlation analysis was carried out. Combined with principal components analysis (PCA), a logistic regression model is developed to predict and diagnose bacterial regrowth and locate the zones with high risks of microbiology in the distribution system. The model gives the probability of bacterial regrowth with the number of heterotrophic plate counts as the binary response variable and three new principal components variables as the explanatory variables. The veracity of the logistic regression model was 90%, which meets the precision requirement of the model.     

基于多种数学模型下的湖南省人口预测研究

区域发展的主体是人,同时区域发展的目的是以人为本。在PILED战略中,人口特别是人力资源的开发是一个关键因素,是关系区域经济、社会、城市化、区域规划等多个因素的重大问题。文章采用自回归模型、马尔萨斯人口模型以及Logistic模型等多种数学分析方法,对湖南省2009-2020年的人口数量做出了科学预测,为湖南省在新的历史机遇期制定相关社会经济发展战略与规划提供相应的依据。     

物流管理中管理与服务辩证关系分析

根据唯物辩证法形式与内容范畴原理,物流管理中管理与服务是一对互为影响的形式和内容的关系。其中,管理是形式,服务则是内容,其矛盾运动揭示了物流管理发展的源泉、动力和实质内容,二者的定位和关系问题直接影响到物流管理的实践活动和物流业效益。因此,物流应正确对待和处理管理与服务、方便管理与提高服务质量的关系问题。     

SWOT战略分析在高校后勤社会化改革的运用研究——以重庆正大软件职业技术学院后勤社会化改革为例

SWOT战略分析又称为态势分析．它是由美国旧金山大学的管理学教授于20世纪80年代初提出来的,是一种能够较客观而准确地分析和研究一个单位现实情况,从宏观上把握发展战略的方法。本文运用SWOT分析对所在学校后勤社会化改革现状进行全面分析研究,对未来发展做出战略选择,取得了很好效果。     

An Ontology-Based Binary-Categorization Approach for Recognizing Multiple-Record Web Documents Using a Probabilistic Retrieval Model

The Web contains a tremendous amount of information. It is challenging to determine which Web documents are relevant to a user query, and even more challenging to rank them according to their degrees of relevance. In this paper, we propose a probabilistic retrieval model using logistic regression for recognizing multiple-record Web documents against an application ontology, a simple conceptual modeling approach. We notice that many Web documents contain a sequence of chunks of textual information, each of which constitutes a record. This type of documents is referred to as multiple-record documents. In our categorization approach, a document is represented by a set of term frequencies of index terms, a density heuristic value, and a grouping heuristic value. We first apply the logistic regression analysis on relevant probabilities using the (i) index terms, (ii) density value, and (iii) grouping value of each training document. Hereafter, the relevant probability of each test document is interpolated from the fitting curves. Contrary to other probabilistic retrieval models, our model makes only a weak independent assumption and is capable of handling any important dependent relationships among index terms. In addition, we use logistic regression, instead of linear regression analysis, because the relevance probabilities of training documents are discrete. Using a test set of car-ads and another one for obituary Web documents, our probabilistic model achieves the averaged recall ratio of 100%, precision ratio of 83.3%, and accuracy ratio of 92.5%.     

读者特征与需求的多元逻辑回归分析

文章以图书馆现刊阅览室的读者和期刊种类为研究对象，对所收集的原始资料进行非条件逻辑回归分析，得出影响期刊读者的主要因素是：高年级、男性、偏远地区、普通专科生、成人本科生、理科专业、入馆日期为2005年8月-10月。