基于多变量公钥密码体制的代理重签名方案

代理重签名方案大多是基于大数分解和离散对数难题设计的,而量子计算机能在多项式时间内求解这些难题,从而给方案造成安全隐患。为此,利用多变量公钥密码体制可以抵抗量子攻击的特性,设计一个新的代理重签名方案。理论分析结果表明,该方案满足内部安全性和外部安全性,且运算效率高。     

Polynomial Chaos Decomposition for the Simulation of Non-Gaussian Nonstationary Stochastic Processes

A method is developed for representing and synthesizing random processes that have been specified by their two-point correlation function and their nonstationary marginal probability density functions. The target process is represented as a polynomial transformation of an appropriate Gaussian process. The target correlation structure is decomposed according to the Karhunen–Loève expansion of the underlying Gaussian process. A sequence of polynomial transformations in this process is then used to match the one-point marginal probability density functions. The method results in a representation of a stochastic process that is particularly well suited for implementation with the spectral stochastic finite element method as well as for general purpose simulation of realizations of these processes.     

Polynomials,radial basis functions and multilayer perceptron neural network methods in local geoid determination with GPS/levelling

The means for determining reference surfaces when using satellite-based positioning techniques differs from the way they are determined using classical terrestrial positioning techniques. The height of any point on earth, as determined by a global positioning system (GPS), is based on the World Geodetic System of 1984 datum, but when using classical terrestrial measurements this height is based on the geoid. However, GPS-derived ellipsoidal heights must initially be transformed into orthometric heights for practical applications. We use geoid models developed with geoid heights for the height transformation, because orthometric height determination methods using classical techniques require time and manpower. In this study, the performances of polynomials, radial basis functions (RBFs) and multilayer perceptron (MLP) neural network algorithms used in local geoid surface modelling were evaluated in the study area. Upon analysis of statistical results, the artificial neural network method was observed to give better results than the other two methods.     

两种添加剂对石蜡针入度的影响

对于一般的 q- 1维正规单纯形利益区域和多重线性多项式模型 ,利用n(≤ q)阶多重线性多项式的最优设计 ,采用了极端顶点设计及棱中心设计方案 ,选用 16个实验数据 ,建立石蜡在两种添加剂的作用下针入度性质的 3阶多重线性多项式的针入度拟合方程 :f(x1,x2 ,x3 ) =- 172 .5 9+5 96 8.91x1- 5 830 .5 7x21+2 5 0 4 .4 4x3 1- 32 .4 9x2 。并对其协同效应、对抗效应和可加效应以及变化趋势进行了研究 ,结果表明 :动物蜡添加剂对石蜡针入度的影响不显著 ,而植物蜡添加剂对石蜡针入度的影响显著 ,并可以利用拟合方程对添加剂作用于石蜡的针入度的物理特性进行预测。这一结果对石蜡新产品的研究具有参考价值。     

Computational problems in the theory of finite fields

We give a survey of selected topics in the theory of finite fields with emphasis on computational aspects including recent advances and open problems.Dedicated to Professor G. E. Wall     

Pulsed electromagnetic heating of microparticles

The application of pulsed heating by a laser beam to determine the thermal properties of microparticles is explored. Two problems are analyzed : (i) spatially uniform heating of the surface of an absorbing microsphere, and (ii) non-uniform surface heating based on Mie theory computations of the electromagnetic energy source. A parametric study shows that the spatially uniform heating model is sufficient when the thermal conductivity of the microparticle is sufficiently large or the Biot number is sufficiently low, but a more rigorous model is needed to predict the temperature distribution with the microsphere for lower thermal conductivity materials. The resulting analytical solutions are compared with previously published experiments involving infrared heating of single spherocarb particles and are shown to be in good agreement with time-dependent surface temperature measurements.     

Stochastic Response of a Random Mass Structure

This paper proposes a polynomial approximation approach for the estimation of the stochastic response of a random mass structure subjected to an evolutionary random excitation. A bounded, monopeak, and symmetrically distributed probability density function, called λ-PDF, together with the Gegenbauer polynomial approximation, is introduced to deal with stochastic dynamic response problems of the random mass structures. The λ-PDF model is used to describe the random parameters in the engineering random structures. And then the Gegenbauer polynomial approximation method is used to reduce the random structures into its deterministic equivalent one. The numerical example shows the effectiveness of the proposed method to explore dynamic phenomena in random structures.     

LIWER ESTIMATES FOR A GENERALIZED SUMS OF LEBESGUE FUNCTION TYPE

1IntroductionI,etX:={x,,*,k=l,2,..',n,n=1,2,..-}beandtriangularmatrixofnodeswith(1)(X,=X,,O=)-1<.T,,,<.Tn,C-'..r.,,<1(=X,,;) 1=X'. 1),n=1,2,-..Putingarethecorrcspondlngfundan1cntalpolynon1ialsoftheI,agranginterpoilation,isthelebesguefunction,andforanyfixednonnegat1veintegersandtiscalledthesumofI,ebesguefuncti0ntype.Tostateourresultweneedtointroducesomeothernotation-Foreachn,n=1,2,';define1相似文献   

Vibration of completely free composite plates and cylindrical shell panels by a higher-order theory

This paper deals with the free vibration of open, laminated composite, circular cylindrical panels having a rectangular plan-form and all their edges free of external tractions. The material arrangement of the shell panels considered may vary from this of the single isotropic (or special orthotropic) layer to that of a general angle-ply lay-up. The analysis is based on the application of the Ritz approach on the energy functional of the Love-type version of a unified shear deformable shell theory. A through-thickness parabolic distribution of the transverse shear deformation is mainly assumed but, for comparison purposes, numerical results that are based on the assumptions of the classical Love-type shell theory are also presented. The Ritz method is a powerful analytical technique since, provided that a complete set of trial functions is employed, it can provide the exact solution of the problem considered in infinite series forms. The mathematical formulation is therefore presented in a general form, appropriate for any set of basis functions. The variational approach is, however, finally applied in conjunction with a complete functional basis made of the appropriate admissible orthonormal polynomials.     

一元多项式的有效赋值算法

给出了一元多项式的一种有效赋值方法,在乘法数量上比ｄｅ Ｃａｓｔｅｌｊａｕ算法低一个数量级,在稳定性上优于Ｈｏｒｎｏｒ格式。