Breaking a remote user authentication scheme for multi-server architecture

Lin et al., (2003) proposed a remote user authentication scheme for multi-server architecture. In this paper, we breaks this scheme by giving an attack. Our attack allows an adversary to impersonate any user in the system, as long as a single authentication message of that user is observed.     

EBSP study of the annealing behavior of aluminum deformed by equal channel angular processing

Commercial purity aluminum (99.5%) was fabricated by equal channel angular pressing (ECAP) up to total accumulated strains of approx. 10. The annealing behavior of material deformed to total strains of approx. 1 and 10 was investigated, using heat treatments of 2 h at various temperatures from 100 to 500 °C. The microstructure of the annealed materials was characterized using the electron back-scatter pattern technique. A number of parameters were determined including the distribution and average values of both the boundary spacings and misorientations. For samples deformed to a total strain of 1, annealing resulted in discontinuous recrystallization. For samples deformed to a total strain of 10, annealing resulted in microstructures exhibiting characteristics of both uniform coarsening and, in a number of places, of discontinuous recrystallization. An attempt was made, based on the boundary spacing distributions, to separate these two components. The grain size after annealing was still however small, being just 6.4 μm after 2 h at 300 °C.     

Application of an anisotropic perfectly matched layer absorber for open boundary truncation in the multiresolution time domain scheme

We apply an anisotropic perfectly matched layer (APML) absorber for open boundary truncation in implementation of the multiresolution time domain (MRTD) scheme. We develop an APML update algorithm to handle a general APML region in the MRTD formulations with the content of the leapfrog algorithm applied in the conventional finite-difference time-domain method. We also discuss the boundary truncations for both perfectly electric conductor (PEC) and perfectly magnetic conductor (PMC) walls using the image techniques. We validate the algorithm by analyzing various guided wave and antenna structures. It is found that the APML performs well for absorbing electromagnetic waves in the MRTD algorithm.     

移动通信系统"单通"故障浅析

重点分析了移动通信系统中,无线及交换系统内语音单通故障的成因；并以朗讯 CDMA 交换系统为例,提出语音系统优化建议；最后结合运维工作,阐述单通故障的处理流程与几种有效处理思路及工具。     

全IP体系的无缝连接需求和实现方法

在全IP体系下,无缝连接将保证用户在跨越同构和异构网络时业务体验的连续性和一致性.无缝连接包括无缝切换和协同两方面内容,需要情景管理、公共无线资源管理、媒体转换以及网络协同等功能实体,从终端的角度看,无缝连接需要基于配置文件、情景和应用自动完成连接的建立、更新和修改.以UMA为例说明了无缝连接的应用和价值.     

基于素性检验思想的不可约多项式判断

论文将Fermat素性检验的思想运用于不可约多项式的判断,给出了一个对于不可约判断问题的Monte Carlo 算法,分析了该算法的计算复杂度问题,并且给出了次数在200以内的检验结果。     

Acquisition and pattern recognition of spectrum information of welding metal transfer

With the creation of a pattern recognition system for metal transfer mode, this article has collected five kinds of spectrum signals in gas metal arc welding (MIG, MAG and CO₂) and take them as training samples. These samples have been pretreated by computer, several key characteristic parameters of the spectrum signal have been creatively extracted, and a corresponding recognition function and a minimum-distance-classifier have been constructed. The results show that the pattern recognition of several kinds of metal transfer modes for the metal gas arc welding can be done successfully, and relative important parameters in welding process, such as the frequency of droplet transfer and the approximate diameter of each droplet, can also be obtained.     

信号的小波尺度-频率表示及其在机械故障诊断中的应用

基于对信号的连续小波变换特点的分析，提出信号特征的小波尺度一频率表示方法。该方法对污染的脉冲信号和正弦信号的应用结果表明该方法能有效提取强噪声背景下的周期成分。以变速器齿轮的故障诊断为例，用该方法对变速箱齿轮振动信号的尺度-频率表示进行分析，结果表明该方法能非常有效地将不同磨损状况的齿轮振动信号的特征表现出来。