基于滞回分配的VBR视频流量带宽管理方案

基于VBR视频流量预测提出了一种新的动态带宽分配算法———滞回算法。与Girish提出的门限算法和Youssef提出的基于GOP场景检测的带宽分配方案相比,对缓存尺寸的需求、信元丢失率等性能有明显提高。大量的仿真表明,该算法能够以较低的开销(带宽重分配次数百分比≤2%)同时兼顾了CLR和带宽利用率,而且只有在缓存队长超过迂回门限时才触发带宽重分配过程,有利于在线实现。     

奥迪A6安全气囊故障诊断与案例分析

一汽大众生产的奥迪A6装配有先进的电子传感式安全气囊(SRS)系统,其豪华程度堪称目前国产轿车配置的顶级产品。由于SRS系统直接关系到乘员的人身安全,在实际检修中,检测人员应对系统元件构成、工作原理、标准诊断流程有所了解和掌握。下面笔者结合实践经验做一总结,希望能对同行们有所启发和借鉴。系统主要元件的构成及功能SRS系统的主要元件有控制单元J234、气囊、爆燃式安全带张紧器和螺据存储器、蓄能器和碰撞数据记录器,因此J234具有系统自检、监控、故障存储、引爆指令及撞车记录等功能。发生碰撞时,J234除了对本系统终端执行元…     

基于BP神经网络的铁路货运量预测

在铁路货运量预测中，为改善传统预测方法数据拟合度不高、外推性不强等问题，提出基于BP神经网络技术的货运量预测模型，该模型采用贝叶斯正则化方法以提高神经网络推广能力。实验比较发现，该模型具有较强的自适应性，其拟合、预测结果优于灰色预测模型GM（1，1）和修正指数回归模型，证实了该方法的可行性和可靠性。     

三菱GALANT和LANCER轿车74A4型自动变速器液压系统的检修

三菱GALANT和LANCER轿车F4A4型自动变速器液压回路如图1所示。     

粒子群算法在确定边坡最小安全系数中的应用

基于圆弧滑动面假定，提出了一种用粒子群优化算法(PSO)确定边坡最危险滑动面及其对应的最小安全系数的方法，并以粒子群优化算法为指导，编制了搜索土坡临界滑动面的程序，将粒子群这一新近发明的进化计算技术应用于工程实际。     

设计制胜的奥迪再次发招

进气格栅历来是最重要的品牌特征，奥迪胆敢用一副拳头般的格栅将上代的风格全盘否定，表明了奥迪对新A6设计团队的信心。的确新A6的身段仍然具有勾人心魂的能力，看到实车更是如此。     

实时ITS数据抽样技术应用软件的设计与实现

本文介绍了ITS数据抽样技术应用软件的设计与实现的过程。通过Oracle、Access数据库和VB编程语言等实现了ITS数据抽样算法，包括误差平方和法(SSE)和互验法(CV)。通过对该软件的测试结果表明，得到的最佳抽样日精度很高，软件的实用性很强。     

DESIGN OF A DIGITAL SIGNATURE SCHEME BASED ON FACTORING AND DISCRETE LOGARITHMS

Objective Focusing on the security problem of authentication and confidentiality in the context of computer networks, a digital signature scheme was proposed based on the public key cryptosystem. Methods Firstly,the course of digital signature based on the public key cryptosystem was given. Then, RSA and ELGamal schemes were described respectively. They were the basis of the proposed scheme. Generalized ELGamal type signature schemes were listed. After comparing with each other, one scheme, whose Signature equation was (m r)x=j s modФ(p) , was adopted in the designing. Results Based on two well-known cryptographic assumptions, the factorization and the discrete logarithms, a digital signature scheme was presented. It must be required that s“ was not equal to p‘q“ in the signing procedure, because attackers could forge the signatures with high probabilities if the discrete logarithms modulo a large prime were solvable. The variable public key “e“ is used instead of the invariable parameter “3“ in Ham‘s signature scheme to enhance the security. One generalized ELGamal type scheme made the proposed scheme escape one multiplicative inverse operation in the signing procedure and one modular exponentiation in the verification procedure.Conclusion The presented scheme obtains the security that Harn‘s scheme was originally claimed. It is secure if the factorization and the discrete logarithms are simultaneously unsolvable.