Determinants of Residential Land-Use Conversion and Sprawl at the Rural-Urban Fringe

We estimate a probit model of residential land conversion using parcel-level data from a rural-urban county in Ohio. Spatial landscape pattern metrics are used to quantify land-use patterns and to link patterns of residential sprawl with factors estimated to influence parcel-level land conversion. Findings indicate that the location of new residential development is influenced by preferences for lower density areas that nonetheless are close to existing urban development. Combined, these forces have generated a moderated pattern of residential sprawl. Spatial error autocorrelation is controlled using a spatial sampling technique that enables consistent estimation of the probit model.     

大学生英语写作错误归因

写作一直是大学英语教学中的一个难点,也是学生学习英语时最头疼的问题。文章分析了大学英语写作中的典型错误,对其成因进行了初步探究,并提出了一些提高英语写作水平的几点建议。     

Globalization, Financial Volatility and Monetary Policy

Recently it has often been claimed that globalization eases the job of central banks as it helps to tame inflation. This is used to argue that central banks (particularly the ECB, referring to the objectives as laid down in the EU Treaty) could or should reduce their efforts in the fight against inflation in favor of supporting the general economic policies of the governments. This paper takes a critical look at this argument, pointing to the structural changes associated with globalization and to the corresponding increase in uncertainty by which the central banks are affected. As an example of this, the increase in financial volatility is analyzed and explained as the result of optimal portfolio allocation, and its implications for monetary policy are discussed.     

Do Vietnamese upland farmers benefit from high world market prices for maize?

For rural households in the north of Vietnam, maize cropping is the main source of income. In the face of the world market price increases of the recent past, we analyze the regional marketing chain of this commodity qualitatively and econometrically investigating to what extent smallholder farmers in developing countries are affected by international price movements. Vietnamese maize markets are found to be well integrated. Recent price hikes have fully transmitted along the regional supply chain so that farmers profited. Nevertheless, adverse factors such as increasing input prices have neutralized these benefits resulting in a decline in real income of smallholders.     

基于电缆网时域反射信号检测与预处理技术研究

运行电缆网时域反射信号检测与预处理技术研究。应用小波分析变换电缆网时域反射信号的奇异点进行检测与预处理误差较大,采用小波分析的反射波消噪技术提出一种小波分析最优分解层数的自适应确定函数算法。     

一种改进的民用GPS异步欺骗技术

针对民用全球定位系统(Global Positioning System,GPS)欺骗中存在的欺骗信号伪码相位同步问题,通过欺骗建模分析得到了主要误差来源于探测系统定位精度。基于传统单路滑动牵引入锁技术,理论分析了功率损失主要来源于载波偏差。针对工程应用中欺骗信号构造时初始码相位超前滞后的不确定带来的欺骗起效时间二值性,提出基于码片误差滞后扩展处理的改进技术,并利用多路并发滑动优化单路滑动时间过长问题。通过软件接收机、商用接收机实验验证了改进的滑动入锁技术在实际应用中具有欺骗起效时间短、欺骗更可靠的特点。该研究成果可为民用GPS欺骗技术研究人员提供参考。     

芯片物理指纹的可用性评估

芯片物理指纹(Physical Unclonable Function,PUF）技术可用于构建新型可信认证体系,具有小型化、低功耗、高安全特性。通过对芯片物理指纹认证性能的研究,提出了对芯片物理指纹可用性相关概念的量化表征。基于芯片物理指纹实测数据进行了更多样本数据的模拟,分析了芯片物理指纹认证参数设置与安全性要求的关系,实现了对芯片物理指纹的可用性的有效评估,为芯片物理指纹技术进一步实现工程化应用提供了参考。     

EA在中国大学生英语学习中的应用

语言是一种复杂的交际工具。语言的学习是一个缓慢且艰苦的试误过程。在这一学习过程中．学习者不可避免的要犯错误，这是一个必要的过程。没有这一过程，反而会阻碍他们的进程。正是通过一个“假想→测试→修正→再假想”这样一个不断修正的过程，学习者逐渐的、艰难的建立着一个越来越接近目标语的语言系统。对大学生在英语学习中的常见错误进行分析(EA)，正是为了揭示这一过程的特点，引导学生不断提高听说读写技能，重视言语行为的交际意义，从而真正学好一门外语。     

Employment adjustment in two countries with poor reputations: Analysis of aggregate, firm, and flow data for Portugal and Germany

This paper supplements aggregate time-series analysis of the speed of employment adjustment with evidence from firm panel and flow data for two countries – Portugal and Germany – sharing unenviable labor market reputations. The Portuguese labor market is often portrayed as terminally inert, while that of Germany as badly ailing. We report broad consistency in the results across data sets in favor of Portugal. In benchmarking Portugal against Germany, the adverse reputation of the former – if not necessarily that of the latter country – may have been exaggerated in contemporary policy debate.We thank, without implicating, two anonymous reviewers of this journal for their helpful remarks on an earlier version of the paper.     

Futures Trading Activity and Commodity Cash Price Volatility

Abstract:   This paper examines the lead‐lag relationship between futures trading activity (volume and open interest) and cash price volatility for major agricultural commodities. Granger causality tests and generalized forecast error variance decompositions show that an unexpected increase in futures trading volume unidirectionally causes an increase in cash price volatility for most commodities. Likewise, there is a weak causal feedback between open interest and cash price volatility. These findings are generally consistent with the destabilizing effect of futures trading on agricultural commodity markets.