我国玉米供需曲线估测与市场预测

通过两阶段最小二乘法估测了我国玉米供需曲线,并预测未来两年均衡价格和净进口量.研究发现影响我国玉米供给的因素有玉米价格、大豆价格、技术进步和成灾率,影响我国玉米需求的因素有玉米价格、小麦价格、人均国内生产总值和总人口;预测未来两年我国玉米价格和净进口量都将呈上升趋势,我国将成为玉米净进口国.     

An MIP model to optimize a Colombian cash supply chain

Financial institutions operate a supply chain where only one product is moved across the network. Although the cash is kept in several nodes to service the demand of final customers, availability causes opportunity cost related with its investment options. When planning the inventory of cash that should be maintained across the network, transportation decisions are also expected to be made. Cash transportation has a high cost, associated with the high risk of theft. Increasing the inventory can reduce the need for transportation, but the opportunity cost can be very high. Moreover, the inventory is also related with the service level perceived for final customers; therefore because of low inventory some people are not able to make some transactions. The aim of this work is to find optimal decisions related with cash inventory and transportation across the network, trying to balance the cost of the service and the quality perceived for final users.     

基于PCA的神经网络在港口货物吞吐量中的预测

分析选取了可能影响港口货物吞吐量的因素,采用PCA技术提取关键因子,最后以提取的关键因子作为神经网络的神经输入元,分别建立BP神经网络预测模型和GRNN神经网络预测模型。以上海港口为例,对港口货物吞吐量进行预测并对预测结果给予分析。     

包钢1000万t铁前原料预测

文章对国内外铁料和燃料的资源状况,作了详尽地调研分析.通过对1 000万t产铁规模铁前原料的平衡计算,得出主要原料--铁料和燃料的需求量和缺口量.     

面向业务分析与预测的企业决策支持系统设计

为了提高企业决策自动化管理水平，运用先进的数据仓库和数据挖掘技术，采用请求响应方式以及规范化的接口结构，提出一个企业信息分析及决策系统的设计和解决方案。根据完善的智能化分析手段，有效的保证决策者的经验与决策支持系统的分析和预测能力相结合，并对企业管理者提供科学准确的分析预测和决策支持。系统可实时地为用户提供有效详细的分析数据，从而大大加快决策进程并有效提高准确性。     

基于T-S模糊逻辑推理的非线性预测模型

建立了基于Takagi-Sugeno模糊逻辑推理的局部多元回归模糊模型(LMRF模型)，将其用于具有小样本数据和非线性特点的宏观非线性系统预测。在多维空间下用C-聚类方法划分模糊子空间，采用带3参数的广义高斯隶属函数．提高了预测的精度，后件参数的辨识采用最小二乘法将减少计算复杂度，交通流量预测实例表明，基于T-S模糊推理的局部多元回归模型用于交通系统能准确地表达交通流量与社会经济的复杂关系，相对于多元线性回归预测模型精度要高得多。     

基于DCS—MINICOM网络通信系统的在线实时优化控制

对进口集散控制系统(DCS)进行深开发，提高原有装置的控制水平，实现在线优化闭环实时控制是工业界普遍关注的研究课题。在美国ABB公司制造的MOD-300型DCS基础上，选用DEC公司制造的Alapha-3800小型机为控制与通信平台，通过PHENIX接口软件、Apclopt软件包及Setcim数据库构建了与DCS的网络信息交换系统，实现了装置的在线优化控制。以中石化某厂、阜海发电厂为例叙述了主要实施过程：优化目标函数的确定，变量的选取，数学模型的建立，优化算法与生产预报模型的形成过程。     

"十五"后三年电力供需形势将十分严峻

根据详实的材料分析中国当前电力供需形势。虽然于2003年全国发电量将提前两年达到“十五”计划目标，但现在电力建设规模严重不足。预计“十五”后三年电力供需形势将十分严峻。当务之急是迅速开工建设一批大中型发电项目。     

State-space forms for higher-order discrete-time models

This paper presents a fundamental study of the connection between continuous- and discrete-time systems. Provided is a definition for discrete-time models, that is discrete-time systems with a continuous-time counterpart, whose order can be higher than that of the continuous-time system. This definition is based on a comparison in a certain sense on the time responses of continuous- and discrete-time systems. A theorem is presented for relating the higher-order discrete-time models to their continuous-time counterparts, which is an extension of a previous theorem for models with order equal to that of the continuous-time system. State-space forms are derived for models obtained through the use of a certain class of hold elements and through the use of mapping models, and these discrete-time systems are shown to be valid according to the definition. Special cases are models obtained using first-order and slewer hold devices, whose convergence to a continuous-time counterpart has not been shown mathematically before, and mapping models corresponding to two-step linear multi-step methods, which have not previously presented in the state-space form. The derived state-space forms provide a convenient way to implement these models for purposes of analysis, design, and implementation of discrete-time systems and finds applications in such areas as digital signal processing, digital simulation, and digital control.     

赣州市五大产业生产方程与组合预测

依据数学和经济学的理论方法，利用赣州市的历史统计数据，对赣州市的农业、工业、建筑业、运输业、商业分别建立生产方程，进而开展组合预测。