产品数据管理(PDM)实施技术研究

主要阐述了产品数据管理技术的基本概念,论述了PDM技术在企业中的应用和实施优势,分析了PDM技术实施的目标、内容和基本步骤。     

液化石油气(LPG)汽车的优点及存在的问题

液化石油气（英文缩写为LPG）做为一种新型的能源,可以有效地治理汽车尾气污染．改善大气环境。本文阐述了LPG汽车的优点及工作中存在的若干问题,并提出解决办法。     

广州地铁1号线加装屏蔽门工程施工经验

在运营线路上加装屏蔽门,一方面要保证运营期间的绝对安全,另一方面又要保证晚上停运后的施工安全高效有序地进行,因此要充分利用原工程竣工图资料,并认真做好现场勘察工作;建立安全组织架构与体系,做好站内相应的防护措施;充分做好白天的施工准备工作,施工材料尽量预安装,以减少现场工作量;做好交叉施工策划,充分利用现场站台纵向和横向空间;制订完善的应急预案,确保现场问题及时解决处理;认真研究并确定施工顺序和步骤;充分与运营部门协调、沟通,使各方形成合力;制订严谨的屏蔽门5000次测试方案和功能测试方案;在车辆段设置管理基地和临时施工场地;在站内设置临时工具房、临时导向标识和提示,在列车上增加语音提示等.     

应用框架的设计及安全管理构件的实现

框架实现了代码重用、设计重用、以及分析重用,从而大幅度降低了开发的成本,提高了生产效率和产品质量。因此,对框架的研究和实践越来越引起学术界和产业界的高度重视。本文通过对某电网调度系统的深入调研,利用领域工程知识,设计了一个基于J2EE平台的综合应用框架,并实现了部分功能。     

基于GM(1,1)模型的交通客运量发展预测

采用灰色系统理论中的GM(1,1)模型,选取2001~2005年我国客运运量数据,分别建立了铁路、公路和民航客运周转量的预测模型,经检验,模型精度等级较高。应用所建模型进行了2006~2010年客运周转量预测,并对照2006年实际运量数据,证明预测结果精度较高。最后讨论了GM(1,1)预测模型在运量预测实际应用中的指标选取、模型检验和应用范围。     

基于GPRS的摊铺机状态远程监测方案设计

本文介绍一种基于GPRS的摊铺机远程监控系统.该系统由传感器参数采集、GPRS通信网络和监测中心上位机软件三大部分构成,对摊铺机模拟机的状态参数进行采集监测,实现远程控制.系统采用GPRS作为通信手段,大大降低了系统的建设费用和维护费用,扩大了系统的监控范围.     

新建地铁控制中心大屏幕系统的设计优化

地铁控制中心的大屏幕系统能够便捷地为调度人员提供直观的信息显示,但也因为能耗大、维护成本高等诸多原因而饱受争议.分析了大屏幕系统在使用过程中存在的争议,提出了大屏幕系统设计的优化和改进措施.随着运营需求的不断增加和对大屏幕系统要求的不断提高,在进行大屏幕系统设计时,必须在合理规划运营需求的同时,积极探讨和使用新技术、新工艺.     

Efficient missing data imputing for traffic flow by considering temporal and spatial dependence

The missing data problem remains as a difficulty in a diverse variety of transportation applications, e.g. traffic flow prediction and traffic pattern recognition. To solve this problem, numerous algorithms had been proposed in the last decade to impute the missed data. However, few existing studies had fully used the traffic flow information of neighboring detecting points to improve imputing performance. In this paper, probabilistic principle component analysis (PPCA) based imputing method, which had been proven to be one of the most effective imputing methods without using temporal or spatial dependence, is extended to utilize the information of multiple points. We systematically examine the potential benefits of multi-point data fusion and study the possible influence of measurement time lags. Tests indicate that the hidden temporal–spatial dependence is nonlinear and could be better retrieved by kernel probabilistic principle component analysis (KPPCA) based method rather than PPCA method. Comparison proves that imputing errors can be notably reduced, if temporal–spatial dependence has been appropriately considered.     

浅谈高速公路桥头跳车的因素及预防措施

桥头跳车一直是高速公路投入使用后普遍存在的问题,本文通过查阅各种资料及本人施工经验,归纳总结了桥头跳车问题产生的原因,提出了桥头跳车问题的预防措施,以便为今后类似工程的施工提供参考。     

The visual impact of development in coastal zone areas

Abstract

The focus of this paper is theoretical, as well as methodological. It reviews previous studies of visual impact and reports research by the author on people's evaluation of the appropriateness of different man‐made facilities in different coastal‐area contexts and other environments. In this study, subjects were asked to react to slides developed through the use of landscape models and experimental facilities to simulate the appearance of a building in the landscape, while systematically varying the visual relatedness between the two. Specific interest centered on the variable of congruity vs. contrast between the appearance of the building and its landscape context, manipulated by co‐varying the attributes of color and size to create a five‐point scale of contrast/obtrusiveness. The hypothesis was that judgments of appropriateness, and to a lesser extent judgments of liking, would vary inversely with level of contrast. The role of two further variables, the functional significance of the building in its setting, and the character of the setting itself, was also investigated. The author reviews methodological issues involved where subjects respond to visual stimuli for purposes of judging change in visual quality. These methodological issues include: stimulus‐selection and problems of simulation, choice of response measures, and choice of respondents, and the treatment of individual differences. The author calls for development of standardized scales and indices such as “perceptually‐relevant environmental quality indicators.”