Modeling and performance analysis of IP access interface in optical transmission networks with packet switching

The article analyzes the influence of the Internet Protocol (IP) access interface on the packet loss probability and delay times in the optical packet switched network. The network and node model have been proposed, and the structure of the IP access interface, including assembler and holder, have been included in the analysis. It has been shown that the increase of the maximum optical packet sizes, as well as use of the holding feature as contention resolution mechanism, decrease the packet loss probability, but introduce delays at the optical network access points. Modeling and analysis were based on the discrete event simulation assuming self-similar traffic sources. IP packet lengths were modeled using empirical data. This work has been conducted while the author was affiliated with the Telecommunication Laboratory, Swiss Federal Institute of Technology (EPFL-STI-ITOP-TCOM), Lausanne, Switzerland     

电信网络管理的望族——TMOS

电信管理及运营支撑是爱立信公司为公用电信网提供的有关管理及运营支撑功能的综合方案，本文介绍了其中的公网管理系统和蜂窝移动网络管理系统。     

网络安全技术研究

网络安全问题已经成为网络发展中急需解决的问题。已经引起人们的重视。给出了网络安全的概念，网络所面临的威胁，提出了解决网络安全的相关技术。     

地域通信网中基于业务量的动态路由研究

本文从地域通信网的特点出发，分析了以前所使用的路由选择方法的优缺点，提出了网控支持的基于业务量的动态中币管理方法，并描述了该路由管理方法的分层结构和在地域网网络管理系统中的具体实现。     

江苏省C3本地电话网组网方式探讨

本文结合江苏Ｃ４本地网的实际情况，说明Ｃ４本地网纳入Ｃ３本地电话网的必要性，例举了４种Ｃ３本地网的组网方式。     

SPAR: stochastic programming with adversarial recourse

We consider a general adversarial stochastic optimization model. Our model involves the design of a system that an adversary may subsequently attempt to destroy or degrade. We introduce SPAR, which utilizes mixed-integer programming for the design decision and a Markov decision process (MDP) for the modeling of our adversarial phase.     

A variable rate multipulse speech coder for CDMA cellular systems

Variable Rate (VR) speech coders are classified into: source-controlled VR coders where the rate is selected depending on the local character of the speech, and network-controlled VR coders where an external control signal selects the coding rate. The first category benefits from the variable rate channels used by Code Division Multiple Access (CDMA) mobile communications. The second category is indispensable for the right behaviour of the CDMA systems under conditions as high traffic levels. The VR speech coder presented in this communication exhibits both types of control. The source control is achieved by means of a Voice Activity Detector (VAD) and a phonetic classifier. The network control acts on the selection procedure of the multipulse excitation sequence to the synthesis filter. This is the main advantage of our VR MultiPulse speech coder because by means of an external signal the bit rate can be changed only every 4 msec, without transitions or distortions. Considering one-way communication, six different operating rates can be externally selected ranging from 4.8 to 9.1 kbps for the active frames; an average bit rate of 380 bps is required for the noise frames.This work has been partly funded by the Spanish Research National Plan under grant no. TIC92-0800-C05-02 and by Northern Telecom.     

Algorithms for flows with parametric capacities

We consider the problem of finding maximal flows with respect to capacities which are linear functions of a parametert [0,T]. Since this problem is a special case of a parametric linear program the classichorizontal approach can be applied in which optimal solutions are computed for successive subintervals of [0,T]. We discuss an alternative algorithm which approximates in each iteration the optimal solution for allt [0,T]. Thisvertical algorithm is a labeling type algorithm where the flow variables are piecewise linear functions. Flow augmentations are done alongconditional flow augmenting paths which can be found by modified path algorithms. The vertical algorithm can be used to solve the parametric flow problem optimally as well as to compute a good approximation for allt if the computation of the optimal solution turns out to be too time consuming.Partially supported by NSF Grants ECS-8412926 and INT-8521433, and NATO Grant RG 85/0240.     

互贯型螯合树脂的研究．Ⅱ．IPN型含偕胺肟基螯合树脂的合成与性能研究

以交联聚苯乙烯－聚丙烯腈树脂为骨架，经功能基化反应制备出含偕胺肟基团的互贯型螯合树脂。对功能基化反应条件和螯合树脂对金的吸着性能，吸着选择性和吸着机理进行了研究。互贯型螯合树脂的吸着性能与互贯树脂的结构有关，而螯合树脂的选择吸着性则与互贯网络无关．