100G以太网CGMII接口的电路设计

随着云计算技术的发展,数据中心的规模和性能必须有很大提升,智能终端通信带宽也必须相应提高。100G以太网相对千兆以太网,数据位宽更大,时钟频率更高。因此,MII接口的设计和实现都面临新的挑战。本文主要研究100G以太网介质无关接口(CGMII)的设计,完成根据协议规定在全双工模式下的MAC帧数据类型的转化,以及对链路故障的处理。     

基于100G＋ROADM传输技术的研究与应用

100G、ROADM技术作为一种新型的网络传输技术,因能对不同波长进行重定向使其被广泛的运用到光传输网的各个领域。本文就现网存在的技术问题,以及100G、ROADM技术的发展及应用情况进行概述和讨论,并提出ROADM组网部署建议。     

【平价法拉利】 富勒G100鼠标

富勒G100编辑评价价格实惠的游戏鼠标,即便不是用来玩游戏,G100的操作感觉以及丰富的功能也让它成为一款值得推荐的产品。     

全面提高机箱性能的3UPXI14槽背板

泛华恒兴发布了一款高性能3UPXI14槽机箱背板PSPXI-3027。     

100G以太网中高位宽并行CRC的简化方法

在100G以太网媒体接入控制器(Media Access Control,MAC)的设计中,需要采用高位宽的并行数据来降低对时钟的要求。在使用并行循环冗余校验(Cyclical Redundancy Check,CRC)时会有一个问题,即需要计算CRC的数据域长度不一定是数据通道位宽的整数倍,导致最后一组数据无法使用数据通道的位宽对其进行CRC计算。为了解决这个问题,本文提出了在帧前填充0的处理方法。仿真和测试结果都验证了该方法的可行性。该处理方法也能应用到其他的通信系统中。     

大容量100G OTN关键技术及其在电力通信中的应用研究

为满足"十三五"期间数据骨干网万兆上联需求以及智能电网业务的发展需要,需建设具备高速率、多业务、大宽带的通信传输网络。文章阐述了100G OTN系统中正交四进制相位调制、相干接收、软判决纠错编码接收等关键技术,分析了100G OTN关键技术在大容量、长距离光传输网中的可行性应用,提出了其在电力通信大容量光传输网中的技术应用方案。方案解决了电力通信大容量光传输网络大跨距大带宽传输的难题,全面提升了网络的安全性、可管理性、可扩展性,为保障公司信息通信网络应用深化和完善提供了坚实基础。     

AIRNOVO AK2400-G100／G70／G30

虽然读者在我们过去的杂志中未曾看到过昂科公司的产品介绍．但实际上在国内的无线局域网市场．昂科已经是一家有着较长发展历史的厂商。我们此次测试的就是昂科针对时下802.11g技术日益流行的市场变化推出的三款无线局域网新品。     

千兆位交换式路由器的背板设计

可同时传输多个包的交换式背板替代拥塞、共享型背板是高性能路由器发展的必然趋势。文章介绍了路由器结构的演变,对交换式背板的需求进行了分析,并研究了设计交换式背板所必须解决的一些问题,最后,给出了一个吞吐率为６４Ｇｂｐｓ的交换式背板的具体设计。     

平民青轴——网际快车G100机械键盘

机械键盘一直是高高在上的产物,离普通用户还比较遥远。但不可否认的是,机械键盘的手感和使用寿命确有较大优势,深受中高端用户的喜爱。也因为如此,部分国内厂商通过采购Cherry原厂轴进行组装,推出了一些高性价比的机械键盘,网际快车G100就是其中之一。     

How to help seismic analysts to verify the French seismic bulletin?

In this paper, classifiers based on Multi-Layer Perceptrons and Support Vector Machines are used in order to classify seismic events that occurred in metropolitan France. The results are exploited in the software RAMSES to help the seismic analysts to conduct efficiently the revision of the weekly French seismic bulletin. With 96.5% of good classification, and less than 7% of the events emphasized for verification, RAMSES strikingly improves the speed of the revision.     

Abstraction and resolution modulo AC: How to verify Diffie–Hellman-like protocols automatically

We show how cryptographic protocols using Diffie–Hellman primitives, i.e., modular exponentiation on a fixed generator, can be encoded in Horn clauses modulo associativity and commutativity. In order to obtain a sufficient criterion of security, we design a complete (but not sound in general) resolution procedure for a class of flattened clauses modulo simple equational theories, including associativity–commutativity. We report on a practical implementation of this algorithm in the MOP modular platform for automated proving; in particular, we obtain the first fully automated proof of security of the IKA.1 initial key agreement protocol in the so-called pure eavesdropper model.     

如何对校园网络的性能进行监视与维护

本文主要分析如何定期收集各种信息,分析网络中各种资源的使用率,及时发现影响网络性能的"瓶颈",并做出相应的优化或者增加网络设备从而提高网络性能.     

如何进行有效的性能测试简

面对复杂的应用系统,测试人员怎样才能进行有效的性能测试？应该如何选择测试策略、如何设计测试方案呢？本文就金保工程应用系统建设中性能测试的实施过程总结一些经验。     

Using the causal domain to specify and verify distributed programs

A system for specification and proof of distributed programs is presented. The method is based directly on the partial order of local states (poset) and avoids the notions of time and simultaneity. Programs are specified by documenting the relationship between local states which are adjacent to each other in the poset. Program properties are defined by stating properties of the poset. Many program properties can be expressed succinctly and elegantly using this method because poset properties inherently account for varying processor execution speeds. The system utilizes a proof technique which uses induction on the complement of the causally precedes relation and is shown to be useful in proving poset properties. We demonstrate the system on three example algorithms: vector clocks, mutual exclusion, and direct dependency clocks. Received 25 July 1995 / 16 September 1996     

用虚拟仪器技术验证牛顿第二定律

牛顿第二定律是经典力学的基本定律之一,为了形象、直观、准确地验证牛顿第二定律,本文利用数字实验系统生动地展示F=ma的关系。通过本实验可以使学生获得更直观的教学感受。     

The use of guidelines to automatically verify Web accessibility

Accessibility is one of the key challenges that the Internet must currently face to guarantee universal inclusion. Accessible Web design requires knowledge and experience from the designer, who can be assisted by the use of broadly accepted guidelines. Nevertheless, guideline application may not be obvious, and many designers may lack experience to use them. The difficulty increases because, as the research on accessibility is progressing, existing sets of guidelines are updated and new sets are proposed by diverse institutions. Therefore, the availability of tools to evaluate accessibility, and eventually repair the detected bugs, is crucial. This paper presents a tool, EvalIris, developed to automatically check the accessibility of Websites using sets of guidelines that, by means of a well-defined XML structure, can be easily replaced or updated.

Use of multiple difference-of-Gaussian filters to verify geometric models

Experiments are reported with a program which recognizes London buses in busy street scenes. The program uses a 3D model of a bus. together with knowledge of camera and scene parameters, to compute the visual appearance of possible target events. In earlier work this took the form of 2D templates, which identify locations within the image where abrupt discontinuities of grey-value are expected. Each template corresponds to an hypothesis which is verified by measuring the agreement between the predicted features and the response of a Sobel filter to the image data. This paper reports an extension to the program which offers improved selectivity, and a more general-purpose method of linking predicted features to detected imageattributes. Multiple difference-of-Gaussian filters perform an initial object-independent analysis of the image to provide an intermediate domain in which object-dependent features, predicted by hypothesized instances of the model, are tested.     

A numerical simulation to verify the stress-free growth of silicon crystal ribbon

Thermal stresses developed during the growth of silicon crystal ribbon have been shown to be negligible, thus eliminating residual stresses and dislocations, if the temperature profile satisfies a second-order partial differential equation inside the ribbon. This has been numerically verified through a finite element model, an outline of which is presented here. This model shows that, for homogeneous isotropic material with temperature independent thermal expansion co-efficients, thermal stresses will vanish if the temperature profile satisfies the Laplacian. A comparison of stresses due to uniform and non-uniform temperature gradients in the plane of the ribbon is also presented. The strategies employed to control the round-off error and to validate the computer model are discussed.