Density estimation in the uniform deconvolution model

We consider the problem of estimating a probability density function based on data that are corrupted by noise from a uniform distribution. The (nonparametric) maximum likelihood estimator for the corresponding distribution function is well defined. For the density function this is not the case. We study two nonparametric estimators for this density. The first is a type of kernel density estimate based on the empirical distribution function of the observable data. The second is a kernel density estimate based on the MLE of the distribution function of the unobservable (uncorrupted) data.     

公有制和其它经济成份并存的效应分析

本文以我国公有制和其它经济成份并存这一重要经济现象为研究对象,从“并存”的一系列纷繁复杂的后果当中提炼出了最突出的问题,并给以多视角的分析,最后给出了“并存”优化的对策建议。     

区域主导产业发展中的地方政府行为研究

地方政府的活动范围应根据市场发挥作用的程度、社会自治的能力加以界定,更好地发挥市场的作用,优化市场经济运行的环境应是政府行为的着眼点。从地方政府官员的意识、赶超愿望、获得新闻界的关注程度等角度探讨地方政府的行为诱导机制,阐明地方政府财政能力、协调能力等方面是导致区域主导产业畸型增长的内因,提出改变地方政府行政模式,是实现地方政府目标与区域主导产业可持续发展的关键所在。     

Awareness of Distributed Denial of Service Attacks' Dangers: Role of Internet Pricing Mechanisms

Denial of Service (DoS) attacks consist of overwhelming a server, a network or a Web site in order to paralyze its normal activity. The additional parameter in Distributed Denial of Service (DdoS) attacks is the distributing strategy. It means that DDoS attacks do not come from a single computer but stem from all accessible channels and servers. Consequences are multiple, ranging from system errors, temporary inability to access the Web site for normal users to challenging the actual reliability of the Internet. Despite this, Internet users show carelessness. The explanation lies in the specificities of DDoS attacks. We explore possibilities to raise users' awareness about the actual amplitude of problems caused by DDoS attacks. We suggest a careful examination of Internet pricing mechanisms and switching from flat to usage-constraining pricing schemes.     

文化是生产力发服的内在动力

随着人类社会的发展,社会的文明程度越来越高,人们对文化的认识也越来越深刻.特别是文化与生产力之间的关系引起了人们的广泛关注.文化对生产力发展起着巨大的推动作用.     

A comparison of several approximations to the power function of the likelihood ratio test in covariance structure analysis*

In this paper we compare alternative asymptotic approximations to the power of the likelihood ratio test used in covariance structure analysis for testing the fit of a model. Alternative expressions for the noncentrality parameter (ncp) lead to different approximations to the power function. It appears that for alternative covariance matrices close to the null hypothesis, the alternative ncp's lead to similar values, while for alternative covariance matrices far from H_o the different expressions for the ncp can conflict substantively. Monte Carlo evidence shows that the ncp proposed in Satorra and Saris (1985) gives the most accurate power approximations.     

Stability and Segregation in Group Formation

This paper presents a model of group formation based on the assumption that individuals prefer to associate with people similar to them. It is shown that, in general, if the number of groups that can be formed is bounded, then a stable partition of the society into groups may not exist. (A partition is defined as stable if none of the individuals would prefer be in a different group than the one he is in.) However, if individuals' characteristics are one-dimensional, then a stable partition always exists. We give sufficient conditions for stable partitions to be segregating (in the sense that, for example, low-characteristic individuals are in one group and high-characteristic ones are in another) and Pareto efficient. In addition, we propose a dynamic model of individual myopic behavior describing the evolution of group formation to an eventual stable, segregating, and Pareto efficient partition. Journal of Economic Literature Classification Numbers: C72, H41.     

《笨花》与《棉花垛》乡土叙述的比较——兼及对《铁凝的<笨花>批判》的批判

《笨花》因为和作者早年的《棉花垛》有相似之处而受人非议。《笨花》以乡土叙述的方式描绘了河北农村的风土人情,但是《笨花》中还混杂了多种西方话语,即宗教、女性话语和民族解放话语,这些与乡土社会本应是相抵牾的。然而作者为了塑造乡土社会的和谐风貌,通过对各种话语的挪移,而使它们与乡土叙述的冲突彻底消解,造成了文本张力的缺失。     

Commodity currencies

This paper looks at real exchange rate behavior by focusing on three OECD economies (Australia, Canada, and New Zealand) where primary commodities constitute a significant share of their exports. For Australia and New Zealand especially, we find that the US dollar price of their commodity exports (generally exogenous to these small economies) has a strong and stable influence on their floating real rates, with the magnitude of the effects consistent with predictions of standard theoretical models. However, after controlling for commodity price shocks, there is still a purchasing power parity puzzle in the residual. The results here are relevant to developing commodity-exporting countries as they liberalize their capital markets and move towards floating exchange rates.