美国空军卫星控制网的现状与发展趋势

近几年的几场局部战争部分表明了现代军事航天系统的重要性。本文主要介绍了美国最重要的一个军事航天测控网－－空军卫星控制网的情况，希望能对了解美国军事航天测控体制有所帮助。     

Asymmetric performance: the market share impact of scale and link alliances in the global auto industry

This study investigates how participating in strategic alliances with rivals affects the relative competitive positions of the partner firms. The paper builds on studies that show significant differences in the outcomes of scale and link alliances. The study argues that the more asymmetric outcomes of link alliances translate into greater changes in the relative market shares of the partner firms, due to unbalanced opportunities for inter‐partner learning and learning by doing. We find support for this argument by examining 135 alliances among competing firms in the global automobile industry, from 1966 to 1995. Copyright © 2004 John Wiley & Sons, Ltd.     

数据流链接技术在军用维修物资编码系统中的应用

本文从军用维修物资业务管理的角度,讲述了军用维修物资的分类体系;从军用维修物资信息管理的角度,讲述了军用维修物资的信息分类;从计算机数据处理的角度,讲述了数据流链接技术在军用维修物资编码系统中的应用,并给出了其应用程序流程.     

物业税的开征对房地产市场的调控作用

从长期看,房价会随着经济的增长而增长。但我国房价近年来每年以30%～50%的速度增长肯定是有问题的。高房价成了目前中国社会各种矛盾的焦点之一。政府可以通过法律与制度来调整目前国内房地产市场严重的利益不均衡。而税收政策就是其中不可或缺的工具。文中从物业税设置的必要性、可行性等方面加以论述,讨论了物业税开征对房价的调控作用。     

Three Corrected Score Tests for Generalized Linear Models with Dispersion Covariates

We develop three corrected score tests for generalized linear models with dispersion covariates, thus generalizing the results of Cordeiro , Ferrari and Paula (1993) and Cribari-Neto and Ferrari (1995) . We present, in matrix notation, general formulae for the coefficients which define the corrected statistics. The formulae only require simple operations on matrices and can be used to obtain analytically closed-form corrections for score test statistics in a variety of special generalized linear models with dispersion covariates. They also have advantages for numerical purposes since our formulae are readily computable using a language supporting numerical linear algebra. Two examples, namely, iid sampling without covariates on the mean or dispersion parameter oand one-way classification models, are given. We also present some simulations where the three corrected tests perform better than the usual score test, the likelihood ratio test and its Bartlett corrected version. Finally, we present a numerical example for a data set discussed by Simonoff and Tsai (1994) .     

数字图书馆防盗链设计以及实现研究

数字资源的拥有者应该设计图书馆数字资源的防盗链方案,提升数字图书馆的防盗链能力。本文通过对数字图书馆的了解,进行数字图书馆防盗链设计的研究。     

Configurations of business strategy and marketing channels for e-commerce and traditional retail formats: A Qualitative Comparison Analysis (QCA) in sporting goods retailing

This article applies a configurational approach to study the fit between retail format, business strategy, and multi-channel setup. Its empirical material consists of five case studies, and a data set of 74 sporting goods retailers in Sweden. Our results show that a retailer can create strategic advantages when its multi-channel setup fits with its business strategy, and that retail format is important for explaining differences in growth and profit, the former being assigned to e-commerce and the latter to physical stores. Moreover, the study reveals that to some extent online channels also have positive performance implications for physical store retailers.     

Link16数据链导航功能实现与改进

基于同步的相对导航与精确定位技术是Link16数据链运行的关键。针对国内文献对该 技术介绍较少的情况,分析了相对导航的基本原理,研究了利用往返计时报文实现精确同步 的方法和步骤,建立了相对导航解算方程以及相对栅格与地理栅格坐标之间的数据转换模型 ,最后提出了一种用GPS/IMU数据融合和卡尔曼滤波方法提高导航精度的方案。应用结果表 明,该方案能显著提高数据链的导航精度。     

基于QualNet的战术数据链三维动态仿真

基于QualNet仿真软 件设计并实现了战术数据链在模拟环境下的三维动态仿真。将战术数据链仿真拓展到三维空 间,加入目标的机动性因素,给出了三维仿真的动态模型及其满足的更普遍关系式,具有一 定的参考价值和指导意义。     

快慢速自适应融合的安全中继选择

针对无线通信中的物理层信息安全问题,在无线安全协作网络中提出了一种基于快慢速链路自适应融合的安全中继选择方法。该方法根据移动速度选择链路自适应类型,根据干扰节点对安全容量的“正”或“负”效应使用或不使用干扰节点,基于安全容量最大化准则进行中继选择。在此基础上,对所提安全中继选择方法进行了性能分析,推导了中断概率表达式。中断概率的仿真曲线和理论曲线很吻合,验证了理论分析的正确性。同时,仿真结果显示,相对于采用单一快速链路自适应,基于所提中继选择方法的安全协作通信系统具有更低的误码率和更大的安全容量,在“正效应”条件下干扰节点有助于提升系统安全容量。