“低保”需求与供给错位了吗？

文章运用探索性空间数据分析方法,并构建空间Durbin计量模型,对2003～2014年间我国城市最低生活保障标准的空间差异及其成因进行了实证分析。研究表明,我国的“低保”需求与“低保”资金供给存在错位的现象,分税制改革与地区分割的最低生活保障制度是造成“低保”需求与“低保”资金供给错位的主要原因。此外,我国城市最低生活保障标准在空间分布上存在显著的空间示范效应,当中央政府提出要向民生倾斜时,地方政府存在竞争提高城市最低生活保障标准的倾向。     

Probabilistic Nonadaptive and Two-Stage Group Testing with Relatively Small Pools and DNA Library Screening

We use a simple, but nonstandard, incidence relation to construct probabilistic nonadaptive group testing algorithms that identify many positives in a population with a zero probability of yielding a false positive. More importantly, we give two-stage modifications of our nonadaptive algorithms that dramatically reduce the expected number of sufficient pools. For our algorithms, we give a lower bound on the probability of identifying all the positives and we compute the expected number of positives identified. Our method gives control over the pool sizes. In DNA library screening algorithms, where relatively small pools are generally preferred, having control over the pool sizes is an important practical consideration.     

Goodness-of-Fit of the Distribution of Time-to-First-Occurrence in Recurrent Event Models

Imperfect repair models are a class of stochastic models that deal with recurrent phenomena. This article focuses on the Block, Borges, and Savits (1985) age-dependent minimal repair model (the BBS model) in which a system that fails at time t undergoes one of two types of repair: with probability p(t), a perfect repair is performed, or with probability 1-p(t), a minimal repair is performed. The goodness-of-fit problem of interest concerns the initial distribution of the failure ages. In particular, interest is on testing the null hypothesis that the hazard rate function of the time-to-first-event-occurrence, λ(·), is equal to a prespecified hazard rate function λ₀(·). This paper extends the class of hazard-based smooth goodness-of-fit tests introduced in Peña (1998a) to the case where data accrual is from a BBS model. The goodness-of-fit tests are score tests derived by reformulating Neyman's idea of smooth tests in terms of hazard functions. Omnibus as well as directional tests are developed and simulation results are presented to illustrate the sensitivities of the proposed tests for certain types of alternatives.     

农村低保三级评议制度及其实施中的偏差治理——以G省K乡为例

实地调查发现,农村低保制度在乡村现行治理结构下出现失效现象。而其根源在于乡镇和村组织之间的实施监督关系变异为乡镇和村之间的合作共议关系,导致低保三级评议制度实施中出现种种偏差,如将低保享受资格作为＂惩罚＂工具,将低保指标作为工作顺利开展的＂抚慰＂、＂公关＂手段等。其深层原因包括村级组织受到乡镇干涉而难以实现独立评议,乡镇监督实际上成为乡镇和村两级组织的＂合议＂,以及县一级组织监督的实质性缺失等。解决此问题的关键在于重构乡镇和村组织间的制度理性,强化监督,促进村民在评议中的参与。     

临界最小努力模型及其扩展在中国的实证分析

最初的临界最小努力模型描述了在一定的转折点将农业剩余人口转化为非农业人口所应付出的最小努力程度 ,对年度努力状况未加细致分析。为此 ,我们对原模型进行了修正和扩展得到计算年度努力程度的修正模型和扩展模型。我们利用原模型和修正模型及扩展模型对中国就业非农化年度努力状况进行实证研究发现 ,利用原模型计算出的结果与实际情况存在较大出入 ,而利用修正模型和扩展模型得到的结果与实际拟合较好 ,扩展模型尤为恰当。我们还将扩展模型用于研究第三产业化的努力程度 ,我们发现 ,在现有发展水平下中国的第三产业化实际上已经很充分。     

A sound interpretation of minimality properties of common belief in minimal semantics

A soundness proof for an axiomatization of common belief in minimal neighbourhood semantics is provided, thereby leaving aside all assumptions of monotonicity in agents reasoning. Minimality properties of common belief are thus emphasized, in contrast to the more usual fixed point properties. The proof relies on the existence of transfinite fixed points of sequences of neighbourhood systems even when they are not closed under supersets. Obvious shortcoming of the note is the lack of a completeness proof.     

生物语言学视角下的语言官能——乔姆斯基语言习得假设之一的论证

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Tail index estimation in small smaples Simulation results for independent and ARCH-type financial return models

Estimation of the tail index of stationary, fat-tailed return distributions is non-trivial since the well-known Hill estimator is optimal only under iid draws from an exact Pareto model. We provide a small sample simulation study of recently suggested adaptive estimators under ARCH-type dependence. The Hill estimator’s performance is found to be dominated by a ratio estimator. Dependence increases estimation error which can remain substantial even in larger data sets. As small sample bias is related to the magnitude of the tail index, recent standard applications may have overestimated (underestimated) the risk of assets with low (high) degrees of fat-tailedness. This paper is a shortened version of the Berkeley Research Program in Finance Working Paper RPF-295. Thanks are to the Center for Mathematical Sciences at Munich University of Technology for generously providing access to computer facilities and to participants at the IAFE 2001 Budapest, OR 2002 Klagenfurt, EIR 2002 London, DGF 2002 Cologne, FBI 2002 Karlsruhe conferences and the 2001 Wallis Workshop for helpful comments. Two anonymous referees provided helpful suggestions in streamlining the material. Niklas Wagner acknowledges a Maple program by Klaus Kiefersbeck and financial support by Deutsche Forschungsgemeinschaft (DFG).     

基于DNA粘贴模型求解最小集合覆盖问题

运用DNA计算模式中基于粘贴运算的粘贴模型求解最小集合覆盖问题.在粘贴模型中,用存储复合体来表示子集,并利用粘贴运算的巨大并行性,可以有效地求解最小集合覆盖问题.举例说明了基于DNA粘贴模型求解最小集合覆盖问题的过程.     

分子集合套理论及其应用

在Ｌ是分子格时，借助于分子极小集概念引入了分子集合套概念，得到了一般Ｌ－ｆｕｚｚｙ集的若干新的表现定理，并给出了它们在拓扑中的应用．