椭圆锥同轴线的特性阻抗

首次提出了一种新型传输线-椭圆锥同轴线,假设其工作模式是TEM模,在球锥面坐标系下分离变量再通过坐标变换成二维平面坐标,并利用图形逼近和取尺寸上下限的几何均值方法计算此种传输线的特性阻抗。     

一种脱机手写体汉字识别的容错编码方法研究

手写体汉字识别是字符识别领域中的难点。为了使机器识别汉字适应于手写体汉字的变形等因素,基于人类认识汉字的容错机理,提出了一种用于机器识字的汉字容错编码方法,以提高手写体汉字识别率。该编码方法首先对横竖撇捺笔划形态给出了模糊化表示;然后定义了仿人拆字的字元集,并给出了易混淆笔划字元的多归类容错编码;接着给出了笔划字元的顺序判断规则和归结了36类简单常用字的部首子结构,并给出冗余的容错编码;进而建立了仿人构字的汉字编码规则和具有容错性的多模板字典,并对《新华字典》中收录的10000余个单字汉字进行了标准编码,重码率为0.48%;最后对HCCORG和NKIM手写体汉字库中的100个手写体汉字进行了仿真识别,识别正确率为96%。试验结果表明,这种编码方法可生成多模板字典,不仅对手写体汉字变形具有较好的容错性,且重码率和误识率较低。     

高斯光束的特征参数在传输变换中的作用

在聚焦、扩束、准直等需要改变光能量分布的场合，考证了高斯光束特征参数b、W0在传输变换中对选择物距、透镜焦距及光学系统的指导作用，考证了虚像存在的条件，并分析了b、W0对变换结果的影响．     

The Identification of Multiple Outliers in ARIMA Models

Abstract

There are three main problems in the existing procedures for detecting outliers in ARIMA models. The first one is the biased estimation of the initial parameter values that may strongly affect the power to detect outliers. The second problem is the confusion between level shifts and innovative outliers when the series has a level shift. The third problem is masking. We propose a procedure that keeps the powerful features of previous methods but improves the initial parameter estimate, avoids the confusion between innovative outliers and level shifts and includes joint tests for sequences of additive outliers in order to solve the masking problem. A Monte Carlo study and one example of the performance of the proposed procedure are presented.     

Certain Inverse Multivariate Hypergeometric and Multinomial Distributions

A sample is drawn from a population in such a way that it contains at least certain numbers from certain of its subpopulations. This paper obtains the frequency function of the number of units in the sample and its distribution over the subpopulations, and suggests some applications.     

Multidimensional scaling models with inequality and equality constraints

Recently, a lot of attention has been brought to constrained estimation theory in multidimensional scaling models. So far, only equality constraints have been thoroughly studied. In this paper, the optimization theory is extended to general multidi-mensional scaling models with both inequality and equality constraints. A Newton-Raphson based algorithm is developed to produce the constrained least squares estimate. To illustrate the theory, some classical color data are reanalyzed in the context of the linear Euclidean distance model.     

机载脊喇叭天线辐射特性分析

基于一致性几何绕射理论分析飞机机体结构对安装在机背上的双脊喇叭天线辐射特性的影响,分析了机载双脊喇叭天线各辐射场分量的计算方法,计算了天线经简化机体散射后的方向图。仿真实验结果表明,机体对天线辐射特性的影响主要在机身表面的反射、结构边缘的绕射,而表面爬行波对天线方向图主瓣的影响非常小,其影响主要在后瓣。计算结果可为天线安装后辐射性能预测和最优化配置提供理论依据。     

Mapping and managing productive organizational energy over time: The Energy Pattern Explorer tool

To strategically manage the deployment of collective human resources toward performance, managers must recognize, interpret, and align the volatile resources of productive organizational energy. Despite relevant prior work, research and practice still lack a comprehensive approach toward analyzing and managing energy patterns over time. We develop a framework for temporal configurations and prototypical trajectories of productive organizational energy. We then introduce the ‘Energy Pattern Explorer’ as a strategy tool to: (1) identify and predict actual patterns of productive organizational energy in organizations, and (2) suggest energy leadership activities specific to current and anticipated changes and patterns of productive organizational energy. We provide examples of how managers can use this tool and conclude with suggestions for research and practice.     

再入体模型截短对天线辐射特性影响

从再入体典型口径天线在无限大平面上的辐射场出发,采用几何绕射法(GTD),计算分析了不同口径分布的再入体缝隙天线赤道面和子午面辐射场随再入体模型纵向尺寸的变化,实验验证了其计算分析结果,从理论分析和实验得出了可忽略截短效应的再入体模型纵向尺寸。     

浅析跳动公差的合理选用

分析了跳动公差的控制特点以及与其它形位公差的关系,并对正确合理使用跳动公差进行了讨论.