基于内存映射文件的进程间数据传输

介绍了Windows操作系统的内存管理方式及Windows操作系统中进程间通信的几种方式,论述了内存映射文件的定义,以及使用内存映射文件在进程间共享内存的原理、操作和使用内存映射文件的方法和步骤。根据内存映射文件在进程间共享数据的原理,实现了多进程间数据传输共享的消息队列,并应用于工程实践中,取得了较好的效果。     

使用Wind32优化内存和文件I／O管理

分析了传统I/O管理中存在的一些问题和Win32部件对象的特性，详细介绍了使用内存映射文件的全过程。为了使用的方便。设计了一个C^ 来包装使用内存映射文件的API函数。并用于实际的编程。具有一定的实用价值。     

内存映射文件及其在广义舒适度仿真中的应用

本文分析了win32系统下的虚拟内存系统模式及内存映射文件的工作机理,介绍了如何用windows API将文件映射至内存,利用原型页表入口技术实现了多个进程之间的数据共享。通过实验数据得出,采用内存映射文件读取高速服役列车的广义舒适度仿真中的超大数据文件,其效率远远高于传统的基于文件I/O方式的数据存取。     

WIN32下利用内存映射文件实现进程间通信

本文介绍了VC＋＋编译环境下利用内存映射文件实现WIN32进程间的通信，并通过实例介绍实现过程。     

基于内存映射文件的仿真系统进程间数据

针对某综合仿真系统进程间进行大数据量快速实时传输的需求,在分析进程间数据传输方法的基础上,采用内存映射文件技术,实现了进程间大数据量的实时传输。结果表明,基于内存映射文件技术的进程间大数据量的快速实时传输,在某综合仿真系统中工作可靠、稳定。     

Win32中多进程间的内存共享数据通信方法

支持多任务操作是 Windows 操作系统的主要优点之一。本文针对32位 Windows 的技术特点,提出了基于共享内存的多进程间数据传输方法,并详细讨论了通过内存映射文件的内存共享实现技术。给出编程实例之后,本文对共享内存技术做了总结。     

Win32中多进程间的内存共享数据通信方法

支持多任务操作是Windows操作系统的主要优点之一。本文针对32位Windows的技术特点,提出了基于共享内存的多进程间数据传输方法,并详细讨论了通过内存映射文件的内存共享实现技术。给出编程实例之后,本文对共享内存技术做了总结。     

内存映射处理网络规划仿真大数据的研究

本文介绍了内存映射的基本原理与调用流程,通过内存映射文件技术解决了无线网络规划软件大数据量中间结果的文件读写效率问题,对传统文件技术与内存映射技术进行了性能对比,展示了软件通过中间结果文件生成的最终结果,使软件既能够满足大规模仿真的需求,同时保证了运行的高效性。     

基于小波变换的高分辨率遥感图像复原算法实现

为了促进遥感图像的后续研究,针对高分辨率遥感图像实现了基于小波变换的迭代收缩（IST）图像复原算法。考虑到算法在复原过程中对内存需求较大,实现过程中采用内存映射文件的方法,将高分辨率遥感图像映射到进程地址空间。针对分块复原图像时通常会伴有边缘跳变现象,影响拼接后的图像质量的问题,使用特殊分块策略对图像进行分块处理。复原算法在VC平台下实现,通过遥感图像复原实验,并对复原图像进行评价分析,复原性能和效率良好。     

基于WINDOWS平台下银行卡系统流水文件的自动识别与分析

在银行卡交易的清分及结算环节,流水文件作为卡组织与其成员金融机构结算、对账的重要媒介,为应对卡组织对账文件种类多、存储信息量大、字段结构复杂以及文件字节过大用户无法人工阅读的特点,通过参数化灵活设置、内存映射及动态定位等技术方式,实现可基于WINDOWS平台的文件处理能力.     

Matched median filter for detecting QAM signals

In this paper, the complex matched median filter (MMF) is developed for QAM signal detection. It is shown that the MMF is robust against impulsive type noise. By combining the MMF and the linear matched filter (LMF), an extended class of matched filters is introduced. These filters combine the desirable properties of MMF and LMF and behave well in varying noise environments. Computer simulations demonstrate that the proposed detectors give a much smaller symbol error probability than the LMF when the noise has an impulsive component and produces only a slight performance degradation in the case of pure Gaussian noise     

On the performance of the electrical equalization technique in MMF links for 10-gigabit ethernet

In this paper, the electrical equalization technique utilized in multimode fiber (MMF) links for 10-Gigabit Ethernet is reported. This paper presents and compares three kinds of equalizers: linear equalizer, decision feedback equalizer (DFE), and a nonlinear finite-impulse-response DFE (NL-FIR-DFE) based on the analysis of nonlinear operations of direct modulation and detection in MMF links. Computer simulations reveal that NL-FIR-DFE exhibits superior performance in comparison with normal DFE. The equalization performance for an MMF channel with bandwidth 500 MHz-km as well as 160 MHz-km is demonstrated. It is demonstrated that with direct modulation of cost-effective vertical-cavity surface-emitting laser (VCSEL) or Fabry-Perot laser, the transmission distance for installed MMF with a bandwidth of 500 MHz-km at 10 Gb/s can be extended to 300 m with an appropriate offset restricted mode launch condition by utilizing normal DFE and to more than 650 m for NL-FIR-DFE. Moreover, it is shown that the transmission distance for an MMF with a bandwidth of 160 MHz-km can reach 300 m with more than seven times bandwidth improvement by using NL-FIR-DFE.     

新一代多模光纤

按照以太网协议建设的光纤局域网的传输速率正迅速升级到1Gbit/s和10Gbit/s这时光纤提出了更高的要求。IEEE正在制定10Gbit/s以太网标准,10Gbit/s以太网标准将考虑采用新一代的多模光纤。文章产 叙述新一代多模光纤的发展前景,然后综述了新一代多模光纤概念、测量新一代多模光纤带宽的新方法和制造新一代多模光纤的技术。     

High-Speed Multimode Fiber Transmission by Using Mode-Field Matched Center-Launching Technique

We report that the center-launching technique can be improved to selectively excite the fundamental mode of multimode fiber (MMF). This ldquomode-field matchedrdquo center-launching technique enables us to excite only the fundamental mode in the MMF and, consequently, avoid the inherent limitations imposed by the differential mode delay. We realize this mode-field matched center-launching technique simply by fusion-splicing a single-mode fiber (SMF) pigtailed transmitter to the MMF. The splicing condition is optimized to expand the core of SMF slightly so that it can match the mode field distribution of the fundamental mode of MMF. The results show that, by using this launching technique, we can achieve the transmission characteristics similar to SMF and drastically increase the bandwidth-distance product of MMF. For demonstrations, we have successfully transmitted 10- and 40-Gb/s signals over 12.2 and 3.7 km of MMF, respectively, without using any dispersion compensation techniques. We have also evaluated the robustness of the MMF link implemented by using the proposed launching technique against the mechanical perturbations such as the lateral offset between fiber connectors, fiber bending, and fiber shaking.     

Max–min fair survivable networks

In this paper, we discuss applications of max–min fairness (MMF) in survivable networks. We focus on two specific applications intended to face failure situations and provide several computational results for each of them. The first application, called simple robust routing, generalizes the multipath routing in order to achieve acceptable levels of traffic demand satisfaction in case of single link failures while avoiding classical rerouting procedures. Such a method can be seen as a special case of dedicated resource recovery schemes. The second application is concerned with two shared resource restoration strategies and the corresponding problems of computing the MMF minimum traffic demand satisfaction ratio vectors associated with the set of single link failures. We consider the local rerouting and end-to-end rerouting without stub-release strategies. Computational results for realistic network instances provide a comparison of different routing and rerouting strategies in terms of traffic satisfaction rate. The question of estimating the bandwidth overhead, which can be required by the “simple robust routing scheme” in comparison with the classical restoration schemes, is also studied and answers based on computational results are provided. This work is in continuation of our earlier works on MMF (Nace et al., IEEE Trans Netw 14:1272–1281, 2006; Nace et al., Comput Oper Res 35:557–573, 2008).     

基于多模光纤偏振烧孔效应的双波长掺铒光纤激光器

基于多模光纤(MMF)引入的偏振烧孔(PHB)效应,研制了一种环形双波长掺铒光纤(EDF)激光器.单模光纤(SMF)-MMF-SMF组成的结构使MMF不同偏振方向的反射模在波长上分开,利用PHB效应实现双波长的输出,输出波长间隔可通过改变MMF的长度改变.实验对比了1.6 m和3.0 m长的MMF输出波谱特性,结果表明...     

Two-dimensional optical power distribution of side-out-coupled radiation from tilted FBGs in multimode fibre

Two-dimensional optical power distribution of the out-coupled radiation from UV-inscribed tilted fibre Bragg gratings (TFBGs) in multimode fibre (MMF) has been side-detected with high spatial/spectral resolution, showing a near-identical radiation mode profile to that measured from the fibre-end detection method. A comparative investigation of the radiation characteristics of TFBGs fabricated in singlemode fibre (SMF) and MMF clearly indicates that the radiation out-coupling is stronger and spatially more confined in MMF. The unique spatial-to-spectral encoding property of the coupling mechanism offers potential application in low-cost WDM devices.     

Image compression using nonlinear pyramid vector quantization

In this paper, we present a new image compression scheme that exploits the VQ technique in a hierarchical nonlinear pyramid structure. We use multistage median filters (MMF) to build the image pyramids. Image pyramids generated by MMF show a better details preservation than the ones generated by Burt's kernel. It is shown that MMF effectively decorrelates the difference pyramids, resulting in smaller first order entropy. Our simulations on natural images show that NPVQ yields a higher SNR as well as better image quality, in comparison with LPVQ. The NPVQ scheme is also appropriate for progressive image transmission.     

多模光纤模式群分集复用系统

多模光纤(MMF)已成为"最后一千米"短距离通信的理想介质,但多模光纤的模间色散限制了其传输能力.模式群分集复用(MGDM)是种光路的多输入多输出(MIMO)技术,该技术利用多模光纤中不同的模式群作为相互独立的信道来传输多路信号,极大地提升了多模光纤的传输能力.设计实现了一个基于75 m梯度型多模光纤(GIMMF)直接检测的两路MGDM通信系统,不同模式群的激发利用选择模式激发实现,利用偏置连接器和多模耦合器实现模式群的复用及解复用,并利用该系统实现了模拟视频信号和非归零码(NRZ)数字信号的传输.     

交流电机绕组的气隙磁势与电势计算

磁势和电势是"电机学"课程的重要概念。本文给出了气隙磁势和线圈波形函数定义,利用空间周期性的傅立叶分解和正弦函数复数表示,计算出气隙磁势与相轴位置,利用磁极和电枢磁场的特点分别计算了相电势,理清了交流电机的基本内容,突出了单元电机分析交流电机的理论依据。