Proportional Odds Models with High‐Dimensional Data Structure

The proportional odds model is the most widely used model when the response has ordered categories. In the case of high‐dimensional predictor structure, the common maximum likelihood approach typically fails when all predictors are included. A boosting technique pomBoost is proposed to fit the model by implicitly selecting the influential predictors. The approach distinguishes between metric and categorical predictors. In the case of categorical predictors, where each predictor relates to a set of parameters, the objective is to select simultaneously all the associated parameters. In addition, the approach distinguishes between nominal and ordinal predictors. In the case of ordinal predictors, the proposed technique uses the ordering of the ordinal predictors by penalizing the difference between the parameters of adjacent categories. The technique has also a provision to consider some mandatory predictors (if any) that must be part of the final sparse model. The performance of the proposed boosting algorithm is evaluated in a simulation study and applications with respect to mean squared error and prediction error. Hit rates and false alarm rates are used to judge the performance of pomBoost for selection of the relevant predictors.     

三阶随机占优准则在证券选择中的应用

通常可以用分布函数和分住数函数描述随机占优准则,Man-Chung Ng列举的两个例子说明在三阶随机占优条件下用两种方法得到的结论是不一致的,这与Levy的观点相反。该文分别将这两种方法描述的三阶随机占优准则用于上海证券市场的基金选择,发现用两种方法在应用中得到的结论并不总是一致的。由此验证用Levy提出的分位数方法描述的随机占优准则进行实证研究是不正确的,一阶和二阶条件除外。     

锅炉压力容器安全阀选型和安装及整定压力需要注意的问题

针对锅炉压力容器安全阀选型和安装及整定压力等存在的问题提出一些需要注意事项。     

基于总成本最小的多式联运运输方式选择

运输总成本是多式联运企业选择运输方式最优先考虑的因素,而总成本最小是目前大多数多式联运企业追求的目标。通过运筹学中的网络图理论构建多式联运运输网络图,基于总成本最小建立模型,将求解最短路径的Dijkstra算法用来求解模型,在求解实例问题过程中印证了整个模型的可行性。     

福建省加权网络应急物资储备点选址

文章在对应急物资储备点选址模型进行概述的基础上,对福建省应急物资储备点进行了分析。选择集合覆盖和加权网络作为理论基础实现储备点选址。并给出福建省应急物资储备点选址的最优方案和遍历应急系统所有区域所需要的时间。     

基于随机需求的物流配送中心选址离散模型研究

针对物流需求不确定情况下的物流配送中心选址问题,对传统模型进行改进,将随机需求变量引入离散型选址模型,利用随机规划理论和遗传算法对实例模型进行求解。结果显示物流需求不确定情况下的随机规划模型的求解结果比假设已知需求情况下的结果真实可信,所需物流费用较少。     

执法监测中正确使用环境标准初探

经过近四十年的发展和完善,我国的环境标准已形成了“两级五类”的完整体系。基层监测人员在执法监测中对环境标准的选择,要结合环境影响批复和污染工艺、排放去向进行综合考虑。在排污许可证上载明的污染物排放浓度与排放标准中规定的浓度限值不一致的情况下,应慎重选取排放标准规定的浓度限值。使用环境标准的基本原则是地方标准优先于国家标准,行业标准优先于综合标准,新标准优先于旧标准,地方政府文件不具有标准效力。     

浅议电动玻璃升降器的设计及布置

为避免在新产品开发阶段,由于设计考虑因素不全面,而造成玻璃升降系统出现升降卡滞、电机烧蚀等质量问题。着重从电动玻璃升降器类型的选择、升降器的设计及布置、升降器主要零部件的设计和材料的选取等方面详细介绍了电动玻璃升降器的设计及布置。     

A320系列货舱门常见故障分析与排除

本文依据A320货舱门工作原理,结合航线的实际工作经验,总结分析了货舱门无法正常开关的故障原因。从液压油路,电路图两个方面分析了货舱门的操作原理,目的是快速找出最可能故障件,减少航班延误,保障航班安全。     

Selecting Sites for New Facilities Using Data Envelopment Analysis

This paper develops a mathematical programming model for obtaining a best set of sites for planned facilities. The model is concerned with those situations where resource constraints are present. The specific setting for the paper involves the selection of sites for a set of retail outlets, wherein the ratio of aggregate outputs to inputs for the selected set is maximal among all possible sets that could be chosen. At the same time, the model guarantees that the only sets of stores allowable are those for which the available resources are used to the maximum extent possible.