基于支持向量机的Web日志用户标志修正算法

针对用户删除Cookie导致的Web日志用户标志不准确的情况,提出了一种基于支持向量机的用户标志修正算法。首先训练一个分类器判断两个会话是否属于同一个用户,然后计算两个不同标志用户之间的相似度,最后将日志进行分组,发现所有删除Cookie的用户并进行标志的修正。通过实验验证了算法的有效性。     

PDM中项目管理的研究与实现

论述了项目管理模块是PDM中的重要组成部分及其作用,建立了PDM中项目管理组织结构及系统模型。提出了一种基于Web技术的分布式项目管理系统的解决方案,来协同在空间上可以分散、时间上允许非同步的项目管理工作。     

一种铁路隧道防灾救援监控系统设计与实现

结合现代通信技术,提出一种隧道防灾救援监控系统设计方案。监控子系统实现对隧道内各设备的集中监控,并与整个系统的调度和指挥中心监控主站保持实时通信,系统构建了基于铁路专用通信网络SDH/MSTP的防灾救援监控通信系统,为监控主站与监控子系统提供以太网业务接口。     

列车对列车无线通信中的信道特性分析

列车对列车(Train-to-train,T2T)通信能为现有车-地专网通信提供保障,其信道特性直接影响上层通信技术的应用.首先,根据铁路运营场景的空间分布结构和菲涅尔带理论提出一种适用于平原和长直隧道场景下追踪列车间直接通信的频率分配方案,并结合由降雨引起电波衰减的估算方法分析多频段无线信道的大尺度衰落.其次,推导T2T通信的最大多普勒频移计算公式,并通过射线跟踪法描述隧道内多径波,以分析小尺度衰落.最后,在同等速度条件下,仿真分析得出T2T通信低频段最大多普勒频移值明显低于车-地通信频移值.     

基于web技术B/C结构下的英语自学系统设计与实现研究

随着科学技术的快速发展与进步,当今社会要求学生学习知识水平越来越高,要求其学习范围更为广泛.因此目前学生仅依凭英语课堂学习还远远不够,很多时候根本无法适应社会发展的需要,所以培养学生自学能力就显得非常重要.由此提出开发一款英语自学系统为英语爱好者提供自学英语平台.文章立足于Web网络,依托B/C结构,应用ASP.NET...     

Flow conditioning system for tri-sonic high pressure aerothermal testing

Blowdown testing offers a cost-effective experimental tool to replicate the aerothermal conditions in numerous high speed systems. The wind tunnel must replicate the inlet operating conditions, while the spatial and time dependent inlet flow conditions should be assessed carefully. This paper provides a design methodology and rules that ensure adequate flow conditioning in high inlet pressure wind tunnels suitable for subsonic and supersonic operation with mass-flow limits ranging from 1 kg/s to 25 kg/s, Reynolds numbers from 10³ (1/m) to 4x10⁷ (1/m), and Mach numbers from 0.01 up to 6. The quality of the proposed flow conditioning system was evaluated using stereo PIV measurements combined with hotwire, Pitot probe, and total flow temperature traverses.     

Surface nitridation of titanium metal by means of a gas tunnel type plasma jet

The surface nitridation of titanium was carried out at a low pressure in nitrogen atmosphere using a gas tunnel type plasma jet. The titanium nitride (TiN) film, 10 μm thick and 2000 HV, could be formed in 10 s. The structure of the TiN film was investigated by XRD. The Vickers hardness on the surface of the film was measured. The effects of deposition conditions on the properties of TiN films (TiN thickness,Vickers hardness, etc.) were investigated, and the advantage of this deposition method was identified from those results.     

Characteristics of high hardness alumina coatings formed by gas tunnel plasma spraying

High hardness alumina coatings were formed at atmospheric pressure by gas tunnel plasma spraying, and the characteristics of these coatings were investigated. The hardness on the cross section of the alumina coating at a short spraying distance was more than 1300 HV, and the thickness of the hard layer increased with an increase of power input. The microstructure of the alumina coating was investigated by microscopy and x-ray diffraction (XRD) methods. It was ascertained that the cell size was small (∼10 μn), and α-alumina was dominant in the high hardness layer of the coating. Finally, the effect of plasma energy was estimated from these results.     

弧齿锥齿轮固有振动特性分析

弧齿锥齿轮主要用于高速、重载的场合,有可能在额定转速内发生强烈的共振,振动应力急剧增大,致使齿轮过早引起疲劳破坏.运用APDL语言自主开发的弧齿锥齿轮建模程序建立了包含齿轮完整结构的有限元模型,计算了不同腹板厚度下的五个弧齿锥齿轮的固有特性,归纳了几种基本齿轮低阶振型种类.结果表明随腹板厚度的增加弧齿锥齿轮的固有频率有所增大,对变形和振动应力的影响效果则与振型有关.     

基于Agent和Web Service的煤矿空间数据共享机制研究

随着GIS和计算机技术的发展,煤矿企业积累了海量多源异构的空间数据。如何消除煤矿企业内的空间信息孤岛问题,实现空间数据共享,是当前煤矿所迫切需要解决的问题。讨论了煤矿异构空间数据的集成方法,创新性地通过Agent和Web Service的技术融合,实现空间数据的智能共享和高效查询,构建一个基于Agent和Web Services的煤矿空间数据集成系统。