Iterative Density Estimation from Contaminated Observations

We introduce an iterative procedure for estimating the unknown density of a random variable X from n independent copies of Y=X+ɛ, where ɛ is normally distributed measurement error independent of X. Mean integrated squared error convergence rates are studied over function classes arising from Fourier conditions. Minimax rates are derived for these classes. It is found that the sequence of estimators defined by the iterative procedure attains the optimal rates. In addition, it is shown that the sequence of estimators converges exponentially fast to an estimator within the class of deconvoluting kernel density estimators. The iterative scheme shows how, in practice, density estimation from indirect observations may be performed by simply correcting an appropriate ordinary density estimator. This allows to assess the effect that the perturbation due to contamination by ɛ has on the density to be estimated. We also suggest a method to select the smoothing parameter required by the iterative approach and, utilizing this method, perform a simulation study.     

中国生态环境现状及其“十二五”期间的战略取向

中国的生态和环境变化态势是稳中有好但改善缓慢。十二五期间中国生态文明建设的基本思路应是:贯彻以人为本的科学发展观,从生产、消费、贸易等领域全方位加速经济发展方式转变,从制度层面形成全社会资源节约、环境友好型发展的合力,优先解决危害人民群众健康的环境问题和实行对环境质量的健康风险管理。为实现十二五末期环境保护和生态建设的主要目标,应统筹经济发展与环境保护的关系,以主体功能区划为依据,合理布局产业,解决重点区域问题;优化制度建设,强化政策导向,通过产业政策和治理行动积极调整产业结构;加大执法监察力度,完善政策协调体制,落实相关部门责任;以人体健康为本优化环境保护相关行政资源配置并形成以健康影响为依据的环境管理制度;通过技术进步提高环境保护水平和环境管理效能;进行农村环境重点整治。     

纳布科天然气管道与欧俄能源博弈

欧盟对俄罗斯能源依赖严重,俄乌天然气纠纷凸显了欧盟能源政策的脆弱性。欧盟能源多元化战略中的纳布科天然气管道项目引起俄欧围绕气源地和运输通道铺设的路线而在中亚-里海盆地、伊朗和外高加索以及土耳其、东欧等过境国展开能源地缘政治博弈,其结果将影响欧俄美关系的进程及对中国-中亚管道气源地形成竞争,而中亚天然气进入中国则是一种互惠的理性选择。俄主导的南溪管道与纳布科管道展开气源地之争,欧盟选择从伊朗进入纳布科取决于伊核问题的解决前景和美伊关系走势。俄格战争导致南高加索局势动荡阻碍纳布科项目的顺利实施。而在俄欧之间则存在着一种能源相互依赖,通过建立俄欧之间能源博弈模型所抽象出来的依赖与竞争表明,俄欧双方更多是通过改变自身收益来达到影响对方行为的目的,双方博弈也是非静态的,各自收益变量不断变化,导致现实中的均衡解也不断发生变化。俄罗斯对欧盟施加压力的成本增高,有利于欧盟能源进口多元化格局的形成。     

经济相互依赖、退出成本与国家间冲突升级——基于动态博弈模型的理论分析

经济相互依赖如何影响国家间的政治关系是一个颇受争议的话题。基于马克.克里森兹的退出模型,作者构建了一个五阶段动态博弈模型,从动态视角考察经济相互依赖如何影响不同级别的冲突,并着重对经济相互依赖如何抑制冲突升级的内在机制进行了理论研究,得出如下结论:随着经济相互依赖的加深,国家间发生低级别冲突的概率将会增加,但是低级别冲突升级为战争的概率下降,即经济相互依赖有助于抑制冲突的升级。最后利用1949～2008年中美间政治经济关系的现实对理论分析的结论做了进一步的说明。     

全球化、失衡的双重运动与“内嵌的自由主义”——基于微观层面的探讨

基于微观层面探讨内嵌的自由主义困境之成因,作者试图提供一种自下而上的解释。分析表明,内嵌的自由主义之所以陷入困境,并非由于它在效率方面不尽如人意,也不能简单地将其归因于全球化的影响。事实上,内嵌的自由主义与新自由主义对应着两种不同性质的全球化。在两种全球化的不同际遇背后,折射出的是从内嵌到脱嵌的根本性转变。两者之争,其本质并非经济效率之争,而是政治力量之争。内嵌的自由主义困境之根源在于双重运动的失衡,即国内政治力量的消长与政治格局的根本性变化。如果人们希望政治钟摆回到一种在推动国际自由化进程的同时亦注重社会保护的状态,就必须期望双重运动的失衡将得到纠正。     

国际关系与国际法跨学科研究之路径

从本源看,国际关系与国际法关系紧密;从学科发展史看,国际关系理论与国际法学相辅相成。正由此,在两个学科的联结被割裂近半个世纪后,跨学科研究又在西方蓬勃兴起,甚至号称一个国际关系与国际法学派正在形成。相比之下,中国的相关研究刚刚起步,《当代国际法的发展:一种从国际关系理论视角的分析》一书正是起步阶段的一部探索性之作。该书是从国际关系理论的视角,对当代国际法与国际组织的实践进行的一种跨学科分析,试图为当代国际法的实践提供另一种途径的理论诠释。无疑,国际关系与国际法的跨学科研究必须克服很多困难,包括跨学科研究的难度、学科内的偏见以及学科之间的隔阂等。不过,正是由于跨学科研究本身能够给两个学科的进步带来的诱人前景,决定了其是一种具有强大生命力的研究路径,并将成为学科发展的必然趋势之一。     

Is inflation targeting a good remedy to control inflation?

Since the 1990s inflation targeting (IT) has been adopted by several central banks as a strategy for monetary policy. It is expected that the adoption of this monetary regime can reduce inflation and inflation volatility. This article is concerned with these issues and makes use of the Propensity Score Matching methodology on a sample of 180 countries for the period from 1990 to 2007. For analysis, the sample is split into two sets of countries (advanced and developing). The findings suggest that the adoption of IT is an ideal monetary regime for developing economies and, in addition to reducing inflation volatility, can drive inflation down to internationally acceptable levels. Regarding advanced economies, the adoption of IT does not appear to represent an advantageous strategy. In brief, the empirical results indicate that the adoption of IT is useful for countries that must enhance their credibility for the management of monetary policy.     

The Herodotus paradox

The Babylonian bridal auction, described by Herodotus, is regarded as one of the earliest uses of an auction in history. Yet, to our knowledge, the literature lacks a formal equilibrium analysis of this auction. We provide such an analysis for the two-player case with complete and incomplete information, and in so doing identify what we call the “Herodotus paradox.”     

Digging out the PPP hypothesis: an integrated empirical coverage

We use several popular tests to test the validity of the Purchasing Power Parity (PPP) hypothesis. In particular, we analyze four classes of tests??standard univariate unit root tests, co-integration, panel unit root tests, and unit root tests for nonlinear frameworks??for a dataset consisting of 20 bilateral exchange rates. Through this approach, we ascertain the effectiveness of each methodology in assessing the validity of PPP. Overall, our results suggest little evidence to support PPP. Among the conducted tests, the Panel Analysis of Nonstationarity in the Idiosyncratic and Common components (PANIC) provides the richest insights by disentangling the possible sources of non-stationarity of real exchange rates. The relevance of using price indices with different characteristics is also pinpointed.     

Export Sector Dynamics and Domestic Growth: The Case of Colombia

Analyses of Colombian data have generally failed to confirm the hypothesis of export-led growth. This paper generates several measures of export diversification and structural change in exports, and argues that these measures are useful in assessing growth externalities generated by the export sector. In a simultaneous-equations framework, increases in the rate of export structural change are associated with accelerated Colombian GDP growth. Export diversification, by contrast, is not a source of economic growth, and the reduced-form relationship between aggregate lagged export growth and GDP growth is weak.