多址通信

0623592 DS-CDMA系统窄带干扰的去除技术[刊,中]/叶奕亮//电讯技术．—2006,46(3)．—156-158(G) 0623593用椭圆曲线密码体制实现CDMA通信的鉴权[刊,中]/姜晓梅//信息安全与通信保密．—2006,(1)．—86-88(L)本文简要分析了CDMA通信系统安全需求,在阐述椭圆曲线密码体制的优点及在无线通信中应用优势的基础上,提出了椭圆曲线密码体制在CDMA通信系统中鉴权的一种实现方案。参6 0623594 OFDM系统的自适应符合同步算法[刊,中]/王顶//信息安全与通信保密．—2006,(1)．—77-79(L)本文提出了一种在OFDM系统中基于导频符号的自适应符号同步新算法,它利用FFT的特性,采用频域同步方法,对符号定时进行估计。该算法计算量小,插入的导频数少,并且同步捕获速度、精度高低,可以灵活调节。仿真结果表明,该算法能简单而有效地获取符号同步,自适应性强。参5     

超椭圆曲线密码体制的研究与进展

椭圆曲线密码是目前最流行的公钥密码体制,超椭圆曲线密码作为椭圆曲线密码的推广,近几年对它的研究也日益被人们重视.在该文中,作者就目前国内外对超椭圆曲线密码体制的研究现状作了综述,并提出了在超椭圆曲线密码体制的理论与实现中急需解决的几个问题.     

椭圆曲线密码体制的应用及其安全性分析

椭圆曲线密码体制已经成为密码学的研究热点之一.相对于其它公钥密码体制,椭圆曲线密码体制有短密钥和计算效率高等优点.本文介绍椭圆曲线密码体制及其在加密和数字签名等方面的应用,并讨论了椭圆曲线密码体制的安全性.     

一种基于构造椭圆曲线方程的数字签名方案

椭圆曲线密码体制是通用公钥密码体制签名中安全性很好的公钥密码体制。描述了非超奇异椭圆曲线方程的构造方法,提出了一种基于椭圆曲线构造方程的数字签名方案,并进行了安全性分析。     

椭圆曲线密码体制的研究

椭圆曲线密码体制（ECC）是利用椭圆曲线点群上的离散对数问题的难解性而提出的一种公开密钥算法,文章以ECC为研究对象,从数据加密角度研究了椭圆曲线密码体制,对椭圆曲线密码体制进行了详细的讨论,并总结了椭圆曲线体制在几个方向的应用。     

ECC密码技术及其优越性

椭圆曲线密码体制是近年来兴起的一种性能优良的公钥密码体制，本文介绍了椭圆曲线密码体制的有关概念和基本理论，将它与其它公钥密码体制进行了比较，阐述了椭圆曲线密码体制的优越性。     

一种基于ECC的高效双向身份认证

椭圆曲线密码体制和零知识证明在密码学里面得到了广泛的研究和应用.文章提出了一种基于椭圆曲线密码体制的零知识证明的双向身份认证方案,该方案用椭圆曲线密码体制代替传统的公钥密码体制,并将椭圆曲线的算法加入到了零知识证明的思想里面,使得认证的安全性和准确度有了很大的提高.     

基于椭圆曲线密码体制与小波分析的秘密信息隐藏

文中利用椭圆曲线密码体制密钥短，安全性高的特点，并运用小波分析技术，将加密通信和信息隐藏相结合，提出基于椭圆曲线密码体制与小波分析的秘密信息隐藏方案。文中对方案各部分进行了详细介绍，并给出信息隐藏的效果图。     

超椭圆曲线密码体制在SET协议中的应用研究

文中介绍了SET协议的运作方式,对超椭圆曲线密码体制和RSA密码体制作了比较,提出了在SET协议中使用基于超椭圆曲线密码体制的的数字签名和数字信封方案,提升了SET协议的安全性和运算速度。     

素数域上椭圆曲线密码体制的软件实现

椭圆曲线密码体制已成为公钥密码研究的主流。介绍了椭圆曲线密码体制的一些数学理论基础,对算法的基础模块进行了说明,讨论了软件实现素数域上椭圆曲线密码算法的一种方法,在DSP6205,主频200MHz的环境下,192比特的ECDSA签名速率70次/秒,验证速率60次/秒。最后对椭圆曲线加密体制的研究与实现进行了全面总结,给出了所完成的工作,对椭圆曲线密码体制的应用前景提出了展望。     

Forced nonlinear precession of the magnetization vector under the conditions of an orientation transition

Forced nonlinear precession of the magnetization vector in a normally magnetized magnetic plate under the conditions of an orientation transition is considered. It is shown that, in the field lower than the form demagnetization field, the variable circularly polarized field causes precession of the equilibrium position of the magnetization vector. It is demonstrated based on a vector model in which the precession period of the equilibrium position is inversely proportional to the squared amplitude of the variable field and the sine of the angle of deviation of the equilibrium position of magnetization from the constant field. It is shown that the critical parameters necessary for excitation of precession of the equilibrium position are the amplitude and frequency of the variable field. Diagrams determining domains of existence of precession of the equilibrium position for different saturation magnetization of a magnetic plate are constructed in terms of the coordinates variable field amplitude-frequency. The role of dissipation of magnetization oscillations in the determination of the critical parameters is elucidated. The features of precession in the presence of asymmetric excitation and in the presence of anisotropy in the plane of the plate are noted.     

多光子Tavis-Cummings模型中运动原子与二项式光场相互作用的量子纠缠

利用全量子理论,研究了多光子Tavis-Cummings模型中运动原子与二项式光场相互作用系统的量子纠缠特性,讨论了不同初始状态下的二项式光场系数和原子运动速度对纠缠特性的影响.结果表明：二项式光场系数不影响场熵演化的周期性,但影响场熵峰值大小.随着原子跃迁光子数的增多,场熵演化的周期性和消纠缠现象逐渐消失.原子运动的速度影响场熵的演化周期,且影响场熵峰值的大小,而原子跃迁光子数的增大,会消弱原子运动速度对场熵演化的影响.当光场处于中间态,原子运动速度较低,且原子跃迁光子数较大时,光场与原子可以长久地处于量子纠缠态.     

有线电视加解密系统研究

有线电视加解密技术是有线电视付费管理的一个重要技术保障。在发射端,先将各路电视视频信号进行同步时基校准后,根据同步图案数据确定的同步图案实现每一路电视信号的同步信号的时基处理,以完成电视信号加密(加扰),随后将各路加密(加扰)电视信号连同数据的调制信号一起发送。在接收端,先根据射频信号解调出同步图案数据,并根据解调出的同步图案数据对射频信号进行群解密(解扰),从而实现了电视信号的单加群解。     

硬盘盘片结构特点及NiP基板CMP研究

分析了硬盘盘片的结构特点及硬盘基板的作用。在超净实验室中,通过调节氧化剂的含量,对硬盘基板进行了化学机械抛光。分析了不同氧化剂的含量对硬盘基板抛光速率的影响。对抛光后的硬盘基板进行了检测。抛光后的硬盘基板的粗糙度基本达到厂家的要求。对有可能造成硬盘基板划伤的原因进行了分析研究,为下一步解决划伤问题的实验提供了理论依据。     

Berechnungsmethoden zur Ermittlung der Schutzstrecke bei U- und Stadtbahnen

One essential component of project planning of train control system plants is the design and calculation of the protective route. At first, definitions of the most important terms are explained. There are three different calculation methods depending on the regard of the slope of the track system as well as on the train mass representable. The simplest method only considers the maximum slope before the signal and the danger point. The second method considers the slope of the track in the form of stairs. The gradient method is presented as a third method. The regard of the inclination gradient occurs here in the form of a twofold averaging. On the one hand the mean value in the form of an integral is formed via the train length. On the other hand averaging occurs in the form of an integral via the braking distance. The middle inclination value found in this way is inserted in the iterative process for the determination of the protective route.     

无驱动硅微机械陀螺

报道了无驱动结构硅微机械陀螺,推导了输出电压方程。从方程表达式可看出,该陀螺输出信号包含旋转载体的偏航和俯仰角速度及自旋角速度的信息。通过实验说明如何在输出信号中提取相关信息,即输出信号的频率表示载体自旋角速度的平均值,输出信号的包络表示载体偏航和俯仰角速度大小的瞬时值,输出信号的极性由输出波形的相位超前和滞后确定。最后给出该陀螺目前所达到的主要性能指标。     

基于红外测温的柜内元件热故障的反问题识别

结合红外辐射理论分别建立了控制柜内部单个和多个元件同时过热时对壳体内表面的红外辐射模型,得到了壳体内表面总的热流密度分布,并针对受热壳体建立二维热传导模型。基于对壳体表面红外成像测温,运用L-M算法进行了导热反问题模拟研究,对控制柜内部单个和多个元件的发热温度和方位进行了识别,最后分析了测量误差对计算结果的影响。结果发现运用L-M算法对单个和多个故障元件的发热温度和方位进行分开反演求解和同时进行反演计算时,都取得了较好效果,求解精度较高。测量误差对发热温度的反演计算结果影响更大。     

激光干扰行间转移CCD串扰现象研究

分析了激光功率密度增加到原来的10倍的时候,激光干扰行间转移CCD的串扰图像部分的灰度值并不是成比例地增加,并对串扰图像进行了仿真。由于光电二极管的溢出是不断进行的,垂直CCD的每个像元都获得所有超过阈值的像元溢出的光生载流子之和。每个超过阈值的像元溢出的光生载流子等于垂直CCD向下移动一个像元所需的时间内溢出的光生载流子。通过求解感光部分中光生电子遵守的方程,得到电子浓度增量和入射光功率的关系,进而仿真出串扰图像。仿真了激光能量为串扰阈值10倍和100倍量级时的串扰图像,仿真结果和实验结果可比。     

Phase-only synthesis of nulls in the sum and difference radiation patterns of the phased array antenna of a coordinate meter

Two approaches to the phase-only synthesis of nulls in radiation patterns (RPs) of the phased array antenna (PAA) of a coordinate meter are considered. The approaches use the specificity of the structure of the sheet of the measuring PAA. Such a PAA forms the sum RP and two difference RPs, which ensure measuring of the angular coordinates of an object. The problem of the phase-only synthesis of pattern nulls in prescribed directions in one or several PAA RPs with the angular orientation of the nulls of difference RPs kept in the RP scanning direction is solved. Design relationships are derived and a RP synthesis method, which is based on iterative univariate minimization of a nonlinear functional and includes analytic determination of the minimum of this functional at each iteration, is described. Examples of the array pattern synthesis are presented. The effect the phasing increment on the depth of formed nulls is analyzed and the dependence of the value of the PAA RP in the scanning direction on the position of the formed null is investigated. The effect of synthesized nulls on the shape of the PAA direction-finding characteristic is analyzed.     

A method for the measurement of the parameters of a two-layer stratified earth

A two-layer stratified model is assumed for the earth. The distances involved are assumed to be sufficiently short that the earth can be considered flat. The measurement of the parameters of the top layer can easily be made from the surface, but the parameters of the lower layer are somewhat more difficult. A method is given for the evaluation of these quantifies in terms of measurements of propagation between two antennas located at the surface of the earth. The theoretical solution for the field of an antenna located at the surface of a flat stratified earth has been given by J. R. Wait. This solution is taken as the starting point; it is put into a form which explicitly shows the influence of the parameters of the lower layer. The method of least squares is then used to evaluate the unknown parameters in terms of the measurements. This process allows the use of a large number of measurements which are essentially subjected to an averaging procedure. This prevents localized irregularities in the earth's surface from unduly affecting the results.