3G中的QoS结构及无线资源分配策略

在3G（第3代移动通信系统）中，为了给不同类型的业务提供不同级别的端到端QoS，网络资源必须进行合理分配。QoS和资源分配是密不可分的，而无线资源分配显得尤为重要。文中提出了UMTS的QoS结构，分3部分对空中接口部分的QoS（即无线资源分配策略问题）进行了讨论：首先提出了一种RRA算法，接着讨论了W－CDMA和TD－CDMA系统的无线资源分配问题，最后讨论了下行链路及上行链路的呼叫允许控制（CAC）。     

Electromagnetic Resistive Drift Instability in Current Carrying Low Temperature Tokamak Edges

It is shown that the purely growing electrostatic rippling mode can couple with the shear Alfven wave to give rise to an oscillatory electromagnetic instability in tokamak edge regions. This mechanism can be one of the causes of electromagnetic fluctuations observed near plasma edges. This instability can occur only in the very low temperature regions where resistivity fluctuations can become important due to large electron-ion collision frequency.     

Model checker aided design of a controller for a wafer scanner

For a case-study of a wafer scanner from the semiconductor industry it is shown how model checking techniques can be used to compute (1) a simple yet optimal deadlock avoidance policy, and (2) an infinite schedule that optimizes throughput. in the absence of errors. Deadlock avoidance is studied based on a simple finite state model using Smv, and for throughput analysis a more detailed timed automaton model has been constructed and analyzed using the Uppaal tool. The Smv and Uppaal models are formally related through the notion of a stuttering bisimulation. The results were obtained within 2 weeks, which confirms once more that model checking techniques may help to improve the design process of realistic, industrial systems. Methodologically, the case study is interesting since two models were used to obtain results that could not have been obtained using only a single model. Supported by the European Community Project IST-2001-35304 (Ametist), http://ametist.cs.utwente.nl/.     

偏振模色散统计特性的研究

利用动态方程研究了偏振模色散矢量的统计特性 ,分别用统计系综和频率系综两种方法进行数值模拟。数值结果表明 ,统计系综和频率系综两种方法的结果一致。在大归一化距离条件下 ,均方根时延的平方随归一化距离线性变化 ;偏振模色散矢量的各个分量服从高斯分布 ,差分群时延服从麦克斯韦分布 ;偏振模色散矢量弥散于整个邦加球     

分散网络制造浅谈

网络社会的制造业将是一个全球化的分散型的制造体系.分散网络制造是基于互联网的制造活动,因此,它具开放的、虚拟的,以及资源和技术更合理配置的特点.其组织模式是多种多样的,按现今国防工业现状,宜采用项目领导小组统一协调和控制下的分阶段动态联盟更为合适.为此,分析了网络无序化、企业属性知识不足、利益分配不易等问题带来的困难,并提出了一些建议.     

回旋管的应用研究

文章论述了推广回旋管应用中所碰到的高功率传输,模式变换和辐射尖锐的波束等技术难点,对现有的准光系统提出了改进措施。     

弱激发氩离子激光的振荡频率特性

通过改变激光器的相对激发,观察到了氩离子激光器振荡频率的演变特性。用模竞争效应对实验现象进行了理论解释。     

电流模式n阶传输函数的OA-OTA实现

提出了一种新的实现任意 n阶电流模式传输函数的网络结构。该电路仅含运算放大器 (OA)和运算跨导放大器 (OTA)有源器件 ,因而适于全集成。适当设置 OTA的跨导值能实现任意高阶传输函数 ,且传输函数的系数可独立调整。文中推导了滤波器的设计公式 ,并给出了截止频率为 1 0 0 k Hz的三阶巴特沃斯低通滤波器实例 ,PSPICE仿真结果表明所提电路及设计公式是正确的     

Adaptive predictive control algorithm based on Laguerre Functional Model

Laguerre Functional Model has many advantages such as good approximation capability for the variances of system time‐delay, order and other structural parameters, low computational complexity, and the facility of online parameter identification, etc., so this model is suitable for complex industrial process control. A series of successful applications have been gained in linear and non‐linear predictive control fields by the control algorithm based on Laguerre Functional Model, however, former researchers have not systemically brought forward the theoretical analyses of the stability, robustness, and steady‐state performance of this algorithm, which are the keys to guarantee the feasibility of the control algorithm fundamentally. Aimed at this problem, we introduce the principles of the Incremental Mode Linear Laguerre Predictive Control (IMLLPC) algorithm, and then systemically propose the theoretical analyses and proofs of the stability and robustness of the algorithm, in addition, we also put forward the steady‐state performance analysis. At last, the control performances of this algorithm on two different physical industrial plants are presented in detail, and a number of experimental results validate the feasibility and superiority of IMLLPC algorithm. Copyright © 2005 John Wiley & Sons, Ltd.