What inventories tell us about aggregate fluctuations—A tractable approach to (S,s) policies

We estimate a DSGE model with (S,s) inventory policies. We find that (i) taking inventories into account can significantly improve the empirical fit of DSGE models in matching the standard business-cycle moments (in addition to explaining inventory fluctuations); (ii) (S,s) inventory policies can significantly amplify aggregate output fluctuations, in contrast to the findings of the recent general-equilibrium inventory literature; and (iii) aggregate demand shocks become more important than technology shocks in explaining the business cycle once inventories are incorporated into the model. An independent contribution of our paper is that we develop a solution method for analytically solving (S,s) inventory policies in general equilibrium models with heterogeneous firms and a large aggregate state space, and we illustrate how standard log-linearization methods can be used to solve various versions of our inventory model, generate impulse response functions, and estimate the model׳s deep structural parameters.     

基于Linux系统的电子罗盘的研究

电子罗盘,也叫数字指南针,是现代人们用电子技术制作的利用地磁场来定北极的一种新设备。本文参考了大量ARM 9的裸机实例,对ARM平台的I2C通讯协议进行了深入研究,最后在QT平台编写了上位机的用户截面,得到了精确度高,误差小的指南数据。为智能机器人的空间定位、无人机的航拍定位,摄像机的云台定位,提供准确的方向计算服务。     

非洲石油与美国国家安全——基于非洲司令部的视角

在美国国内石油产量下降和世界主要产油区中东政治局势恶化的大背景下，美国认为非洲石油是实现其石油来源多元化战略的选择之一，为此美国设置了单独处理非洲事务的非洲司令部，从而揭示了非洲石油与美国国家安全之间的紧密联系。     

国际贸易就业影响的国际比较——H-O-S及贸易乘数理论对贸易大国的适应性实证分析

国际贸易的就业影响，理论界并没有统一的认知，其中影响最大的有H-O-S和对外贸易乘数理论。11国比较分析基本证实了这些理论的现实意义，但由于受全球化和信息技术革命的影响以及不同国内经济形势的影响而复杂多变：H-O-S对就业质量影响的解释强于对就业数量的影响，对就业影响的静态效应的解释优于动态效应；对外贸易乘数理论则是对发展中国家的解释强于发达国家，对20世纪的解释超过21世纪初，对长期静态的解释优于短期动态。     

美国乔治敦大学访问观察与启示(一)——师资管理

本文介绍了美国乔治顿大学师资管理制度,并总结出其三大特点,借以提出我们在学习和借鉴国外先进经验的同时,应从我国高校师资队伍建设的实际情况出发,不断改进和完善现行的政策措施,为建设高素质的教师队伍而做出努力。     

The relative price of tradables and nontradables and the U.S. trade balance

The real exchange rate is defined as the relative price of nontradables and tradables. An index of the relative price is constructed for the U.S. and used to explain net exports. The index appears to perform better in explaining net exports than a comparable purchasing power parity real exchange rate. The relative price of nontradables, in turn, is shown to be cointegrated with a set of variables that drive the demand for and supply of nontradables. These variables capture long-run structural and demographic changes of the U.S. economy, such as the increased demand for medical services.     

美国2000年人口普查数据初析

本文利用美国 2 0 0 0年人口普查的初步数据 ,对其人口发展变化的一些主要特点进行了简要的分析 ,分析的重点是性别、年龄和种族结构以及人口的分布与再分布。文章认为美国人口状况变化的所有特点都与国际国内人口迁移有着密切的关系     

绝对有源二端口网络S参数存在范围的研究

本文将给出绝对有源二端口网络S参数的存在范围。这个存在范围的边界是针对|S_(22)|,|S_(11)|平面内,散射矩阵元S_(11)和S_(22)的模的大小给出的。研究表明:在已给出S参数四个模中的三个和四个幅角的情况下,绝对有源条件通常给出散射参数的第四个模的上、下限。在文章的最后将给出一些简单的例子,以说明理论结果的有效性。     

The Manipulation of Voting Systems

In this paper we consider several ways in which voting systems can be manipulated and we pose some related ethical questions. Our focus is on the recent phenomenon of vote trading or vote swapping that was invented in 2000 and used in the 2000 and 2004 U.S. Presidential elections. Vote trading is an Internet-based technique that sought to allow Democrats in heavily Republican states (like Texas) to effectively vote in swing states (like Florida), where their votes would have more impact. We also look at some other new ways that voting systems can be manipulated and we consider the general question of whether there exist voting systems that cannot be manipulated. David Hartvigsen is a professor in the Management Department of the Mendoza College of Business at the University of Notre Dame. He has a Ph.D. in Mathematics from Carnegie Mellon University and his research is in the areas of Operations Research, Optimization, and Algorithms.