数理统计在生产技术中的应用

本文从数理统计的规律入手,用数理统计的几种常用方法,通过正交试验,选择最合适的工艺方案,从而提高注塑件的合格率.     

墙体砌块保温性能和强度的正交试验分析

采用正交试验的方法分析和研究了多因素作用下墙体砌块的保温性能和抗压强度，并使用极差分析方法对试验测试结果进行分析，得到了影响墙体砌块导热系数和抗压强度的主次因素，确定了墙体砌块的合理配比，为墙体保温砌块的设计和制备提供依据．     

信道估计偏差对空时编码的OFDM系统性能的影响

本文研究了采用空时编码的OFDM系统的性能，通过Monte Carlo仿真分析了系统性能和信道估计偏差对系统的影响。     

不同需求规律下的航材安全库存量研究

安全库存是有效处理航材供应过程中遇到的各种突发情况的重要保证,针对航材需求量波动变化的实际情况,对航材安全库存量开展了深入研究。首先,研究了不同航材类型及其安全库存量需求的特点;其次,分析了航材需求分布类型,进而研究了不同需求量变化规律的确定方法;然后,研究建立了不同需求量规律下的航材安全库存量的确定方法;最后,通过算例验证了方法的可行性和有效性,为飞机制造商和航空公司的航材管理提供了有效方法和切实指导。     

多用户MIMO-OFDM系统中一种子载波分配算法

介绍了多用户MIMO-OFDM系统中的Hungarian子载波分配算法，然后针对其计算复杂度过高的缺陷，提出一种局部最优的子载波分配算法，并与Hungarian子载波分配算法进行仿真比较。结果表明，该算法使系统总数据速率仅下降1．7％，而其计算复杂度却大幅减小，提高了资源分配的效率，符合高速无线系统资源实时分配的要求。     

Asymptotic distributions in random graphs with applications to social networks

Various kinds of subgraph counts have been proposed as important statistics in the social sciences: for instance, in connection with studies of the structural properties of social networks. Since the empirical structure in question often involves an element of randomness, subgraph counts are random variables and, consequently, we need to describe their probabilistic properties. In this paper we give a survey of results dealing with the asymptotic distributions of general subgraph counts for a number of standard graph distributions. Although we do not include proofs for all the results, we illustrate the methodology used through studies of asymptotic behaviour for certain subgraph counts.     

PRICING CALLABLE BONDS BY MEANS OF GREEN'S FUNCTION1

This paper derives a closed-form solutin for the price of the European and semi-Amirican callable bond for two popular one-factor models of the term structure of interest rates which have been proposed by Vasicek as well as Cox, Ingersoll, and Ross. the price is derived by means of repeated use of Green's function, which, in turn, is derived from a series solution of the partial differential equation to value a discount bond. the boundary conditions which lead to the well-known formulae for the price of a discount bond are also identified. the algorithm to implement the explicit solution relies on numerical quadrature involving Green's function. It offers both higher accuracy and higher speed of computation than finite difference methods, which suffer from numerical instabilites due to discontinuous boundary values. For suitably small time steps, the proposed algorithm can also be applied to American callable bonds or to any American-type option with Green's function being explicitly known.     

头孢地尼胶囊的处方工艺研究

为优选头孢地尼胶囊的处方工艺并考察其重现性及稳定性,根据辅料相容性结果,采用正交设计试验,以4种介质溶出相似性(f2因子)为指标综合评分,筛选最优处方。以羧甲基纤维素钙为崩解剂,聚氧乙烯(40)硬脂酸酯为增溶剂,二氧化硅为助流剂,硬脂酸镁为润滑剂,采用湿法制粒工艺。结果表明,优选的头孢地尼胶囊处方工艺合理,成品质量稳定。     

叠加共轭对称训练序列的OFDM系统时频同步方法

针对正交频分复用（OFDM）系统对同步错误率和频率偏移敏感的问题,提出了一种叠加共轭对称训练序列的OFDM系统时间和频率同步方法。该同步方法将快速傅里叶逆变换（IFFT）调制后的序列构成具有共轭对称特性的训练序列,并叠加到OFDM数据符号上;在接收端,利用叠加训练序列和融合循环前缀信息来获取OFDM系统同步信息。理论分析和仿真表明：在信噪比为5 dB时,该同步算法定时同步正确概率已接近100%;在信噪比为4 dB时,频偏估计精度可以达到10-4;该同步算法不仅具有更好的同步性能,而且节省系统的有效带宽以及降低系统的计算法复杂度。     

墙体参数模糊下穿墙雷达运动目标成像

针对墙参数模糊条件下运动目标成像速度慢、墙参数重建精度差等问题,提出了一种改进拟牛顿-粒子群优化(Limited Broyden Fletcher Goldfarb Shanno-Particle Swarm Optimization,LBFGS-PSO)算法,建立了LBFGS-PSO算法模型,解决了传统拟牛顿算法和粒子群算法计算速度慢、误差较大等问题。该算法与块正交匹配追踪（Block Orthogonal Matching Pursuit,BOMP）算法相结合不仅可以精确重建边墙位置,还能够准确地重建多径效应环境中的运动目标和静止目标,算法的计算速度和精度得到了一定程度的提高。仿真结果和数据分析验证了所提方法的性能。