cdma2000-1x系统中GPS时钟算法

本文从一个简单、完善的自动机模型出发,介绍了一种正确获取GPS同步时钟的方法,并将其应用于cdma2000-1x系统中。数学推导表明,采用本文提供的算法获取的GPS同步时钟可以有效减少由于GPS时钟硬件的不稳定因素而造成的时钟精度损失,并能周期性地校正所取得的GPS时钟,控制时钟误差精度在100ns范围内。此算法实现简单,计算结果表明,该算法可以大幅度提高时钟精度。     

航天器的非相干高精度测速方法及实现

随着深空探测和天基测控系统的发展和应用，采用相干应答机将使星载系统变的复杂且测速精度很难提高。本文对非相干测速原理进行了讨论和公式推导，给出了系统设计方法。在精度分析的基础上，给出了设计参数图表。分析了非相干测速系统中测距音辅助捕获的实现方法，并分别讨论了ESA标准和CCSDS标准情况下非相干测速的实现方法。     

直升机载雷达侦察系统目标定位精度分析

本文介绍了直升机载侦察雷达对目标的定位原理和定位过程,分析了定位过程中载机自身定位的方法和坐标转换的过程,并在此基础上给出了影响直升机载侦察雷达对目标定位误差的因素及误差组成。     

Is precise econometrics an illusion?1

Abstract

Many empirical economists say that the teaching of econometrics is unbalanced, and students are not well-prepared for the serious problems they will encounter with real data. Here, the author considers the problem of noisy data, which is present in most econometric studies, but receives far too little attention. Most econometric studies are done in a world of low signal-to-noise ratios, and educated common sense suggests that we cannot expect precise results in such an environment. Sensitivity analysis shows that the apparent precision of reported econometric results is generally an illusion, because it is highly dependent on error term independence assumptions.^1,2     

Understanding MNEs׳ decline in the adoption of locally developed technology standard in China: A positioning and cognitive perspective

Asian countries are becoming more and more active in participating technology standard development. In this paper we study the impact of this change on multinational enterprises (MNEs) using the case of TD-SCDMA, an international technology standard of 3G mobile communications. During the development of this technology standard, MNEs׳ market share dropped dramatically. A major contribution of this study is analyzing the underlying mechanism governing MNEs׳ interpreting TD-SCDMA as a threat rather than an opportunity by integrating two streams of literature. We also discuss the possible strategies for MNEs to maintain their market leadership position when local firms are able to lead international technology standard development.     

论古镇旅游形象定位及其提升——以四川罗城古镇旅游目的地为例

旅游形象已成为旅游研究和开发的新领域,旅游形象的定位和提升对旅游目的地的规划与开发具有十分重要的意义。随着古镇旅游热潮的掀起,针对特色古镇的旅游形象定位和提升势在必行。罗城古镇因其独特的船形街建筑布局而扬名海内外,但其旅游形象需要在游客头脑中创造性的明确定位,并不断获得提升。     

周跳探测法在北斗精度定位中的应用研究

介绍了北斗卫星导航系统的发展现状以及北斗卫星的组成,运用载波相位测量卫星信号,得出卫星观测过程中存在卫星周跳现象。在此之后,解析了该卫星导航精度定位的误差来源,一共能够分成三种不同的类型,分别指的是：与该卫星自身有关联的误差;与其信号传播路径有关联的误差;与接收机以及测站有关联的误差。在此步骤结束之后,剖析了周跳的定义与特性,除此之外也分析了周跳对精密定位带来的影响。最终,通过仿真方法得到了有无周跳状况下的高次差法的影响。     

Institutional stakeholdings and better-informed traders at earnings announcements

Utama and Cready [Utama, S., Cready, W.M., 1997. Institutional ownership, differential predisclosure precision and trading volume at announcement dates. Journal of Accounting and Economics 24, 129–150] use total institutional ownership to proxy for the proportion of better-informed traders, an important determinant of trading around earnings announcements. We argue that institutions holding small stakes cannot justify the fixed cost of developing private predisclosure information. Also, institutions with large stakes generally do not trade around earnings announcements since they are dedicated investors or face regulations that make informed trading difficult. However, institutions holding medium stakes have incentives to develop private predisclosure information and trade on it; we show that their ownership is a finer proxy for the proportion of better-informed traders at earnings announcements.     

消费领域的量化自我:研究述评与展望

量化自我是指消费者对自我数据进行收集并经由数据获得自我知识的过程。量化自我能增强消费者的自我精准管控和行为理性,驱动消费者行为方式的转变。数据驱动的量化自我时代正在来临,全新的商业逻辑正在被建立起来。消费者的行为正从非标准化向精准化转变。鉴于此,越来越多学者开始围绕量化自我展开研究,在清晰界定量化自我概念的基础上,分析量化自我的参与动机与阶段性过程,关注量化自我带来的消费者精准化消费方式转变。本文系统回顾了量化自我相关研究,阐释了量化自我的概念与本质,从量化自我的类型与效用、动机与过程等方面对相关研究进行了述评,整理提炼了量化自我在消费领域的应用现状,并在此基础上明确了量化自我研究尚需解决的问题和未来的研究方向。     

Management by the Numbers: A Formal Approach to Deriving Informational and Distributional Properties of “Unmanaged” Earnings

We explore the theoretical relation between earnings and market returns as well as the properties of earnings frequency distributions under the assumption that managers use unbiased accounting information to sequentially decide on real options their firms have and report generated earnings truthfully, with the market pricing the firm based on those reported earnings. We generate benchmarks against which empirically observed earnings‐returns relations and aggregate earnings distributions can be evaluated. This parsimonious model shows a coherent set of results: reported losses are less persistent than reported gains, decision making diminishes the S‐shaped market response to earnings and earnings relate to returns asymmetrically in the way documented by Basu [1997]. Furthermore, the implied frequency distribution of aggregate earnings is neither symmetric nor necessarily single‐peaked. Instead, it may exhibit a kink at zero and look similar to the plots reported by Burgstahler and Dichev [1997]. However, within our model, none of these phenomena are due to reporting noise, bias, or some undesirable strategic managerial behavior. They are the natural consequences of using past earnings as the basis for value increasing managerial decision making that in turn generates the future earnings on which future decisions will be based.