评选计分中的问题及改进方法

由于算术平均数易受极端数据的影响,现行由评委集体评选计分的方法,往往不能反映大多数评委的意见。本文分析了现行评分方法中的问题,提出了三种改进方法。     

二元函数可微性的四则运算与复合运算

本文给出了用定义法证明二元函数可微性的四则运算法则与复合运算法则。     

The variable-interval arithmetic coding using asymptotic deterministic randomness for data compression and encryption

Different from the traditional way which compresses the data first and then encrypts the compressed bit-stream later, a novel compression and encryption scheme using variable model arithmetic coding and coupled chaotic system can encrypt and compress the input plaintext synchronously. However, there will be a compromise between the amount of compression achieved and the amount of security incorporated, because the compression efficiency is determined by the key bit-stream. In this paper, an improved scheme using variable-interval arithmetic coding and asymptotic deterministic randomness has been proposed. The improved scheme is secure because the key bit-stream generated by the asymptotic deterministic randomness can resist previous attacks against chaotic encryption. In addition, the compression efficiency will not change with the key bit-stream, because the statistical model will no longer be changed. The results show that the new scheme can achieve high security and compression efficiency.     

Exact D-optimal designs for a linear log contrast model with mixture experiment for three and four ingredients

This study investigates the exact D-optimal designs of the linear log contrast model using the mixture experiment suggested by Aitchison and Bacon-Shone (1984) and the design space restricted by Lim (1987) and Chan (1988). Results show that for three ingredients, there are six extreme points that can be divided into two non-intersect sets S₁ and S₂. An exact N-point D  -optimal design for N=3p+q,p≥1,1≤q≤2$N=3p+q,p\ge 1,1\le q\le 2$ arranges equal weight n/N,0≤n≤p$n/N,0\le n\le p$ at the points of S₁ (S₂) and puts the remaining weight (N−3n)/N$(N-3n)/N$ on the points of S₂ (S₁) as evenly as possible. For four ingredients and N=6p+q,p≥1,1≤q≤5$N=6p+q,p\ge 1,1\le q\le 5$, an exact N-point design that distributes the weights as evenly as possible among the six supports of the approximate D-optimal design is exact D-optimal.     

最陡下降算法在MTD滤波器设计中的应用

针对雷达中动目标检测技术中滤波器组设计,从普遍采用基于最小最大化的优化原则出发提出了一种改进优化原则。该方法具有明确物理含义,即是使输出杂波功率最小,从而使得优化问题简化为最小化目标函数,大大简化了MTD滤波器设计中优化问题的求解难度。文中采用最陡下降算法求解该问题,通过计算机仿真,可以看到该方法与原来采用方法具有相似的结果,为工程应用提供了一种简单、实用的方法。     

基于结构化信息检索系统的数据搜集技术的研究

本文在已有的传统信息检索系统中数据搜集技术研究基础上,采用了正向最大匹配和逆向最大匹配法的分词技术和基于向量距离的分类技术,建立了可以将XML文档映射到关系数据库的信息检索系统,从而大大提高了信息检索的效率。     

基于BP神经网络的信息商品价格预测模型

从信息商品价格的特点和BP神经网络的功能出发,借助样本训练集和改进的BP算法提出了基于BP神经网络的信息商品价格预测模型,并对模型的泛化精度进行了讨论,最后进行了仿真实验.     

分组密码算法的测试方法研究

安全性是分组密码最重要的设计准则。该文基于分组密码算法,分析了算法的多种安全性测试方法和测试理论,提出相应的测试统计量。采用AES算法中的一个8×8S盒,以一组长为1048576b的随机数为测试序列,进行实际安全性测试。测试结果表明测试统计量符合实际测试结果,从而验证所提出的测试统计量具有实际可行性,有力地保证了分组密码的安全性设计。     

供应链收入共享契约协调的随机期望值模型

本文研究了供应链契约协调中的收入共享契约.建立了具有缺货成本的供应链收入共享契约协调的随机期望值模型,推导了实现分散供应链协调的收入共享契约参数之间的关系,分析了收入共享机制在改进供应链整体运作绩效方面的作用.设计了求解随机期望值模型的混合智能算法,进行了收入共享契约协调模型仿真实验,探讨了收入共享契约参数变化对供应链成员绩效的影响.结果表明,本文建立的收入共享契约协调的随机期望值模型具有实际意义,并在随机需求条件下协调了供应链运作.