电信级以太网中PBT技术与应用研究

电信级以太网是一种新兴的传输汇聚层解决方案，同时是目前技术研究的热点。在多种电信级以太网的实现技术中，PBT（Provider Backbone--Transport）技术得到众多厂商和运营商的关注。文章主要对PBT的网络结构、解决方案、应用及其特点进行了探讨。     

Optimization models for the single delay management problem in public transportation

Passengers travelling in public transportation networks often have to use different lines to cover the trip from their origin to the desired destination. As a consequence, the reliability of connections between vehicles is a key issue for the attractiveness of the intermodal transportation network and it is strongly affected by some unpredictable events like breakdowns or vehicle delays. In such cases, a decision is required to determine if the connected vehicles should wait for the delayed ones or keep their schedule. The delay management problem (DMP) consists in defining the wait/depart policy which minimizes the total delay on the network. In this work, we present two equivalent mixed integer linear programming models for the DMP with a single initial delay, able to reduce the number of variables with respect to the formulations proposed by the literature. The two models are solved by a branch and cut procedure and by a constraint generation approach respectively, and preliminary computational results are presented.     

Stochastic resonance in circadian rhythms

The effect of fluctuations in the two-variable discrete delay model proposed earlier by us [1] for the circadian rhythm of the fungal species Neurospora Crassa is studied. We have investigated the effect of parametric and additive noise in two different regimes namely, steady-state and Period-1 regimes. It is found that under the influence of noise coherent oscillations are generated in the steady-state. Oscillations are preserved and robust to a wide range of noise intensity in the Period-1 regime. The oscillations in both these regimes are always found to be close to the circadian period (21.5 h). Coherence resonance is observed when parametric or velocity additive noise is added near the Hopf bifurcation. Finally, the implications of fluctuations in circadian rhythms are discussed. This article is dedicated to Professor Karl Jug on the occassion of his sixtyfifth birthday.     

改进802.1x认证技术的研究

文章介绍了802．1x协议的基本概念和原理，对802．1x协议在以太网安全认证管理中的实际应用进行了分析，指出了802．1x协议存在的漏洞。为解决权限管理、地址分配等方面存在的问题，提出了新的方法和实用的改进方案。     

实现Ethernet over SDH的嵌入式系统研究

简要介绍了Ethemetover SDH(EoS)系统的结构原理，阐述和分析了EoS的LAPS协议核心技术，给出了使用FPGA完成SDH网络和以太网的连接，从而实现EOS的嵌入式系统设计方案。     

单支方法的收敛性

本文讨论用单支方法数值求解一类多刚性时滞微分代数方程的收敛性。我们获得了A－稳定的且p阶经典相容的单支方法（时滞部分用线性插值）的整体误差估计。     

全业务运营的城域网建设

概述了全业务运营对城域网的需求,讨论了现网存在的问题,并探讨了城域网升级改造的一般策略和技术方案。     

Stability and Synchronization of a Ring of Identical Cells with Delayed Coupling

We consider a ring of identical elements with time delayed, nearest neighbour coupling. The individual elements are modelled by a scalar delay differential equation which includes linear decay and nonlinear delayed feedback. The linear stability of the trivial solution is completely analyzed and illustrated in the parameter space of the coupling strength and the coupling delay. Conditions for global stability of the trivial solution are also given. The bifurcation and stability of nontrivial synchronous solutions from the trivial solution is analyzed using a centre manifold construction.Dedicated to Professor Shui-Nee Chow on the occasion of his 60th birthday.     

基于TCP／IP的雷达操控及BIT系统实现方法

针对雷达系统对全机操控和故障检测系统的设计要求,结合以往的设计经验,详细介绍了一种基于网络的全机操控和故障检测系统的设计原理及实现方法。     

Flush Optimizations to Guarantee Less Transient Traffic in Ethernet Ring Protection

Ethernet ring protection (ERP) technology, which is defined in ITU‐T Recommendation G.8032, has been developed to provide carrier grade recovery for Ethernet ring networks. However, the filtering database (FDB) flush method adopted in the current ERP standard has the drawback of introducing a large amount of transient traffic overshoot caused by flooded Ethernet frames right after protection switching. This traffic overshooting is especially critical when a ring provides services to a large number of clients. According to our experimental results, the traditional FDB flush requires a link capacity about sixteen times greater than the steady state traffic bandwidth. This paper introduces four flush optimization schemes to resolve this issue and investigates how the proposed schemes deal with the transient traffic overshoot on a multi‐ring network under failure conditions. With a network simulator, we evaluate the performance of the proposed schemes and compare them to the conventional FDB flush scheme. Among the proposed methods, the extended FDB advertisement method shows the fastest and most stable protection switching performance.