Experimental Demonstration of SCM-PON Monitoring with Baseband Embedded OTDR

The combination of subcarrier multiplexing and passive optical networks can provide an efficient and cost-effective solution for fiber and wireless convergence in access networks. Moreover, to reduce operational expenditures, a reliable monitoring technique should provide in-service evaluation of the physical layer. Here, we perform the experimental demonstration of an SCM-PON system with baseband embedded optical time-domain reflectometer monitoring. Different modulation formats were tested to evaluate the penalty generated by the monitoring system. Based on the long-term evolution downlink test model (E-TM 3.1), our results show negligible power penalty while achieving a ~12-dB dynamic range with 10-m spatial resolution.     

超越PC盈利模式：Android打造全新业务平台

基于Linux内核的Android作为一个完整、开放、免费的手机平台由开放手机联盟(Open HandsetAlliance)开发。其通过丰富的网络功能、并行多任务环境,以及无界限的应用程序等特色受到业界厂商和广大消费者的广泛关     

一种应用于高清视频模拟前端的多功能开关电容可编程增益放大器

A multifunctional programmable gain amplifier(PGA) that provides gain and offset adjusting abilities for high-definition video analog front-ends(AFE) is presented. With a switched-capacitor structure, the PGA also acts as a sample and holder of the analog-to-digital converter(ADC) in the AFE to reduce the power consumption and chip area of the whole AFE. Furthermore, the PGA converts the single-ended video signal into differential signal for the following ADC to reject common-mode noise and interferences. The 9-bit digital-to-analog converter(DAC) for gain and offset adjusting is embedded into the switched capacitor networks of the PGA. A video AFE integrated circuit based on the proposed PGA is fabricated in a 0.18- m process. Simulation and measurement results show that the PGA achieves a gain control range of 0.90 to 2.34 and an offset control range of –220 to220 mV while consuming 10.1 mA from a 1.8 V power supply.     

Wavelet‐based data compression for flow simulation on block‐structured Cartesian mesh

A data compression method based on image encoding techniques is presented for a flow simulation data set. An input flow field data set is converted into the octree structure by discrete wavelet transform, and then quantized finely or coarsely depending on its importance in the flow field. Embedded zerotree wavelet encoding as the image encoding technique and entropy encoding reduce the data size by making use of the octree structure created previously. The present compression method is incorporated in a block‐structured Cartesian mesh method called Building‐Cube method. The Building‐Cube method gives not only good performance in the flow simulation but also consistency with the embedded zerotree wavelet encoding in the data compression. Three compression cases for incompressible and compressible flow simulations, including a large‐scale simulation with O(10 ⁸) mesh points, demonstrate that the present compression method gives both high compression ratios and good qualities of compressed data. Copyright © 2013 John Wiley & Sons, Ltd.     

基于ARMLinux的EWS过载性能研究

在EWS(嵌入式Web服务器)过载情况下,网络包以泊松流的形式高速到达,MCU(微处理器)几乎被完全用于网卡中断处理,高层的处理任务得不到执行,EWS就出现了系统拥塞现象。在此情况下,对一个基于ARMLinux的EWS的收包过程进行了分析,并把EWS的收包过程抽象为网卡中断处理和TCP/IP处理两部分。根据二级串连排队网络的理论,建立了收包过程模型并对此模型进行了分析,提出了一种在轻量过载的情况下,使用轮询机制处理,在系统拥塞非常严重的情况下,触发关中断处理的轮询-关中断耦合的EWS拥塞解决方案。最后对一个基于ARMLinux的EWS的性能进行了试验分析和验证。     

埋入式电容、电阻技术之探讨

就各种埋入式电容和电阻材料特性以及相应制程分别做出比较,并指出设计工具以及测试方法等需要继续改进,但埋入无源元件的应用前景将更加广泛。     

基于嵌入式技术的网络开票系统的设计

本文介绍了一种基于嵌入式技术的网络开票系统的设计方法,该系统采用客户端-服务器的形式,在实现了税务数据的实时采集、同步传输与反馈的同时,也充分保障了数据安全,为税务信息化建设所面临的问题提供了新的解决思路。     

高效双Hash线速浮动字符串匹配

提出了一种在FPGA上易于实现的高效双Hash浮动字符串匹配算法,其优点是消耗FPGA资源少,处理速度快,并且模式串可以方便地在线更新.     

μC/OS-III在80386保护模式下的移植

文章介绍了一种将μC/OS-III移植到Intel 80386处理器上，使其能够借助于DOS的资源，在保护模式下正常运行的方法。通过解析内核相关代码、CPU相关代码和板级支持包代码这三部分代码，讲述了将实时操作系统μC/OS-III移植到80386处理器保护模式下的全过程。最后给出了在保护模式下运行μC/OS-III的实例。     

General properties of some families of graphs defined by systems of equations

In this paper we present a simple method for constructing infinite families of graphs defined by a class of systems of equations over commutative rings. We show that the graphs in all such families possess some general properties including regularity and biregularity, existence of special vertex colorings, and existence of covering maps—hence, embedded spectra—between every two members of the same family. Another general property, recently discovered, is that nearly every graph constructed in this manner edge‐decomposes either the complete, or complete bipartite, graph which it spans. In many instances, specializations of these constructions have proved useful in various graph theory problems, but especially in many extremal problems. A short survey of the related results is included. We also show that the edge‐decomposition property allows one to improve existing lower bounds for some multicolor Ramsey numbers. © 2001 John Wiley & Sons, Inc. J Graph Theory 38: 65–86, 2001