基于嵌入式关系数据库存储的货运杂费收缴管理系统的设计与实现

嵌入式关系数据库以其快捷灵活的特性被广泛应用在各种与数据库技术紧密结合的信息系统中.本文以货运杂费收缴管理系统为背景,详细介绍嵌入式关系数据库的设计和实现;对货运杂费以及货运杂费收缴管理系统的总体设计进行了系统性概述.     

Freight Data Assembling and Modeling: Methodologies and Practice

Abstract

In comparison to personal travel, freight movements within large metropolitan areas are much less studied. Most conventional transportation models and planning analysis that disregarded freight flows have been criticized on the plausibility of their results and conclusions. To alleviate these problems, this study proposes a non-survey based approach to assemble and process freight data in a systematic way. A freight origin–destination (OD) matrix of freight flows can be developed using secondary data sources. The estimated freight flows can be loaded together with conventional passenger flows onto the regional highway network of a large metropolitan area. As a case study, this non-survey based approach was applied to build a freight OD and study the traffic flows in Los Angeles. It concluded that this approach can be used to analyze urban freight movement in a low-cost way in which planning agencies can overcome the common omission of freight flow information in their transportation plans.     

A model system for the ex-ante assessment of city logistics measures

This paper proposes a model system developed in order to support ex-ante assessment of city logistics measures. The model system allows us to simulate the choices of each decision-maker involved in the urban freight transport and logistics and to investigate how the policies and the following measures can influence her/his choices.The model system is an open architecture and consists of two levels: commodity and vehicle. The commodity level allows us to analyse the attraction and acquisition movements taking into account the effects due to city logistics policy implementation affecting the end-consumer and retailer/wholesaler/producer (restocker) choices. The freight sold in each urban shop (or in general urban business) is estimated starting from consumption demand and, then, the restocker’s choices for restocking are analysed in depth. The vehicle level focuses on the restocking process and the links between retailer and wholesaler/producer operating in the study area. This level allows us to investigate the impacts of implementing city logistics measures on journey time, timing and path used for restocking the urban retail businesses.     

铁路笨零货物装载优化模型和算法

笨零货物装载优化问题是NP完备问题。根据笨零货物运输条件和铁路现场实际操作情况,建立以车辆装载率最大化为目标的装载优化数学模型,约束条件包括:货物合重心偏移量的约束;重量约束;体积约束;下部支撑约束;稳定性约束等。采用遗传算法进行求解,详细阐述用遗传算法求解该问题的关键技术,重点论述二维、三维装载的算法实现。给出算法实例,表现出算法能得到满意的结果。