铁路客票系统数据一致性的实现技术

本文分析了分布式数据库系统数据一致性的实现方法，介绍了客票系统中采用的两种实现数据一致性的技术：复制服务器技术和数据库通信技术，以及这两种技术的实现机制。     

铁路货运投入产出相对有效性评价分析

根据数据包络分析与层次分析法的相关原理,在确定货运投入要素和产出要素的基础上,建立铁路货运投入产出相对有效性评价体系与模型。并以1995—2005年铁路货运相关数据为基础,通过模型计算投入产出相对有效性值、投入指标的松弛变量及产出指标的剩余变量,并对有效值进行完全排序,最后结合所得数据分析投入产出非相对有效的原因。     

CTCS-2-200C列车运行控制设备数据分析和维护

ATP的维护是确保列车运行的基础.为了列车正常的运行,必须通过对列车运行数据,主要是故障数据.SAM和.MID文件的分析,找出列控设备故障,完善设备.     

地质雷达信号采样定时控制

针对地质雷达信号数据采集过程中,采样时刻的定时精度与定时范围难于兼顾的实际,基于斜波发生器原理,用高分辨率数模转换器生成基准比较电压,实现高精度可编程定时电路。可编程计数范围为16bit,实际最小定时单位达8ps,折合采样频率高达50GHz。使用该定时器的地质雷达,采样时刻抖动小于1ps;室内条件下用2GHz天线在3m范围内探测移动金属板,测量误差为1%;野外环境下用100MHz天线对湖底6 2m内的不同目标进行勘探,测量误差在5%～8%范围内,实现地质雷达对地下目标体的高精度定位。     

ERP实施中的基础数据

企业在ERP系统实施中数据准备和维护贯穿了项目的全过程。保证数据的准确性、完整性、及时性对企业能否实施成功起着至关重要的作用。本文根据实际工作经验总结了制造型企业在实施ERP过程中基础数据整理的要点和注意事项,为即将实施ERP系统的企业提供一些帮助和参考。     

编制接触网概预算数据处理方式的研究

计算机技术、软件技术和信息技术的发展,通过计算机编程可以快速提高对接触网各类数据的统计、处理和计算,以方便编制接触网工程概预算.此文从建立关系型数据库、数据标准库和关系数据对应库入手,对各个工程设计阶段的接触网线材和零部件等数据进行归类、统计和处理,通过开放自由组合建立起工程数量与概预算定额的对应关系,按要求自动输出规定的数据格式.将输出数据复制进入概预算编制软件,即可完成单项概预算编制.     

数据挖掘在铁路电子商务中的应用

电子商务是铁路信息化的重要组成部分,通过分析铁路电子商务系统建设的主要内容,阐述了数据挖掘在铁路电子商务中的作用,构建了数据挖掘在客货票信息系统中的应用模型。     

Improving the physics of a coupled physical–biogeochemical model of the North Atlantic through data assimilation: Impact on the ecosystem

Several studies on coupled physical–biogeochemical models have shown that major deficiencies in the biogeochemical fields arise from the deficiencies in the physical flow fields. This paper examines the improvement of the physics through data assimilation, and the subsequent impact on the ecosystem response in a coupled model of the North Atlantic. Sea surface temperature and sea surface height data are assimilated with a sequential method based on the SEEK filter adapted to the coupling needs. The model domain covers the Atlantic from 20°S to 70°N at eddy-permitting resolution. The biogeochemical model is a NPZD-DOM model based on the P3ZD formulation. The results of an annual assimilated simulation are compared with an annual free simulation.With assimilation, the representation of the mixed layer depth is significantly improved in mid latitudes, even though the mixed layer depth is generally overestimated compared to the observations. The representation of the mean and variance of the currents is also significantly improved.The nutrient input in the euphotic zone is used to assess the data assimilation impact on the ecosystem. Data assimilation results in a 50% reduction of the input due to vertical mixing in mid-latitudes, and in a four- to six-fold increase of the advective fluxes in mid-latitudes and subtropics. Averaged zonally, the net impact is a threefold increase for the subtropical gyre, and a moderate (20–30%) decrease at mid and high latitudes.Surface chlorophyll concentration increases along the subtropical gyre borders, but little changes are detected at mid and high latitudes. An increase of the primary production appears along the Gulf Stream path, but it represents only 12% on average for mid and high latitudes. In the subtropical gyre centre, primary production is augmented but stays underestimated (20% of observations). These experiments show the benefits of physical data assimilation in coupled physical–biogeochemical applications.     

Using data assimilation in laboratory experiments of geophysical flows

Data assimilation is used in numerical simulations of laboratory experiments in a stratified, rotating fluid. The experiments are performed on the large Coriolis turntable (Grenoble, France), which achieves a high degree of similarity with the ocean, and the simulations are performed with a two-layer shallow water model, using the SEEK method for data assimilation. Since the flow is measured with a high level of precision and resolution, a detailed analysis of a forecasting system is feasible. The procedure is tested for the baroclinic instability of a two-layer vortex. It is shown that the method of data assimilation properly captures the details of the initial flow perturbation. Then it is shown by sensitivity studies that an error of the model, attributed to small non-hydrostatic effects, can be distinguished from the error growth associated with the intrinsic instability of the system. Finally, it is experimentally demonstrated that the velocity field in the lower layer can be well controlled by data assimilation limited to the top layer.     

Identifying Time-of-Day Breakpoints Based on Nonintrusive Data Collection Platforms

To ensure the effective operation of traffic signal systems, different signal timings should be designed to accommodate traffic pattern variations. One of the greatest challenges is the identification of appropriate time-of-day (TOD) breakpoints, where different signal timings could be implemented during the time periods between two consecutive breakpoints. This research presents an advanced cluster analysis aimed at identifying TOD breakpoints for coordinated, semiactuated modes when it is necessary for multiple intersection operations to be considered simultaneously. Different from previous studies, this proposed methodology considers the time of traffic occurring as one dimension in clustering and uses continuous traffic data obtained through innovative, nonintrusive data collection techniques, which significantly improve this method's performance. The operability of this proposed method is demonstrated in a case study of a corridor located in Tampa, FL. The traffic simulation results reported in this article reveal that this novel procedure performs better than existing TOD signal timing plans.