Testing the Equality of Two Exponential Distributions

This paper proposes an overlapping-based test statistic for testing the equality of two exponential distributions with different scale and location parameters. The test statistic is defined as the maximum likelihood estimate of the Weitzman's overlapping coefficient, which estimates the agreement of two densities. The proposed test statistic is derived in closed form. Simulated critical points are generated for the proposed test statistic for various sample sizes and significance levels via Monte Carlo Simulations. Statistical powers of the proposed test are computed via simulation studies and compared to those of the existing Log likelihood ratio test.     

Getting low educated and older people into work: The role of fiscal policy

Raising employment, in particular employment among older individuals and low educated individuals, stands high on the agenda of policy makers in many OECD countries. Increased sensitivity in recent years to rising inequality has made the challenge only larger. In this paper we evaluate alternative fiscal policy scenarios to face this challenge. We construct and use an overlapping generations model for an open economy where individuals differ not only by age, but also by innate ability and human capital. The model allows us to study effects on aggregate employment, per capita income and welfare, as well as effects for specific age and ability groups. We show that well-considered fiscal policy changes can significantly improve macroeconomic productive efficiency, without increasing intergenerational or intragenerational welfare inequality. Our results strongly prefer a reduction in the labor tax rate on older workers and on all low-wage earners, financed by an overall reduction in non-employment benefits. An alternative financing option is to raise the consumption tax rate. These results are to be seen as long-run effects for economies at potential output.     

Social time preference revisited

The article reconsiders the implications of the choice of pure social time preference for intergenerational equity in the presence of a time-consistent utilitarian social welfare criterion. The analytic framework is a setting with overlapping generations, lifetime uncertainty, population growth and technical progress. The analysis identifies upper and lower bounds for the feasible range of social discount rates and draws a corresponding distinction between “gerontocratic” and “Stalinist” optimal plans. The paper corrects a number of inaccurate propositions in a related earlier contribution by Marini and Scaramozzino (2000) to this journal.

Recursive Equilibrium in Stochastic Overlapping‐Generations Economies

We prove the generic existence of a recursive equilibrium for overlapping‐generations economies with uncertainty. “Generic” here means in a residual set of utilities and endowments. The result holds provided there is a sufficient number of potentially different individuals within each cohort.     

On the Similarity Structure of Order Statistics

In this article, we address the similarity structure between pairs of order statistics of an identically distributed independent random variables X₁,…, X_n. The overlapping coefficient (Δ) of Weitzman (1970 Weitzman , M. S. ( 1970 ). Measures of overlap of income distributions of white and Negro families in the United States . Technical Paper No. 22 , Washington , D.C. , U.S.A : Department of Commerce, Bureau of Census . [Google Scholar]), is used to assess the degree of similarity or closeness between pairs of order statistics. It appears that the degree of the similarity between any of such pairs is independent of the parent distribution. Using this notion, it is shown that for i < j, the degree of similarity between distributions of the ith and the jth order statistics decreases as i and j sunder. Some possible biometric applicability of the value of Δ are explored. In particular, the use of this measure in estimation of the number of possible strata, subgroups or natural subdivisions in a population are suggested.     

量词的数量语义特征与语法功能

从数量语义特征看,量词重叠并未产生空间量的变化,量词重叠量变发生在时间维度上,此外数量短语具有时问性和层级性,它们都不具有体词性的数量语义特征而具有谓词性的数量语义特征。从句法功能上看,量词与量词结构也不具有体词性,而具有谓词性。量词体词性的误会可以从“理论影响、意义、运用、产生”四方面来看。     

Fuzzy duocentric community detection model in social networks

The main goal of this paper is to present a clustering model to identify duocentric communities in the complex networks. A duocentric community is built around two central nodes which are as close as possible to other nodes, while the central nodes are connected enough to each other to shape the center of the community. To detect such communities, we develop a new objective function based clustering model. The network's nodes are assigned to the duocentric communities by the type-2 fuzzy numbers which indicate the degrees of belonging to the communities by upper and lower membership values. Generated interval type-2 fuzzy membership values by our proposed model are able to determine how much each node belongs to the both central nodes and how it is shared among communities. Also, the compatible verification index with the proposed model is introduced to evaluate and compare the results of the proposed model with the existing approach in the literature. Finally, the performance of the proposed algorithm is validated by detecting duocentric communities in three artificial networks and two real social networks.     

The Effectiveness of Multistage Ranked Set Sampling in Stratifying the Population

The spectral analysis of Gaussian linear time-series processes is usually based on uni-frequential tools because the spectral density functions of degree 2 and higher are identically zero and there is no polyspectrum in this case. In finite samples, such an approach does not allow the resolution of closely adjacent spectral lines, except by using autoregressive models of excessively high order in the method of maximum entropy. In this article, multi-frequential periodograms designed for the analysis of discrete and mixed spectra are defined and studied for their properties in finite samples. For a given vector of frequencies ω, the sum of squares of the corresponding trigonometric regression model fitted to a time series by unweighted least squares defines the multi-frequential periodogram statistic IM(ω). When ω is unknown, it follows from the properties of nonlinear models whose parameters separate (i.e., the frequencies and the cosine and sine coefficients here) that the least-squares estimator of frequencies is obtained by maximizing I ^M(ω). The first-order, second-order and distribution properties of I ^M(ω) are established theoretically in finite samples, and are compared with those of Schuster's uni-frequential periodogram statistic. In the multi-frequential periodogram analysis, the least-squares estimator of frequencies is proved to be theoretically unbiased in finite samples if the number of periodic components of the time series is correctly estimated. Here, this number is estimated at the end of a stepwise procedure based on pseudo-Flikelihood ratio tests. Simulations are used to compare the stepwise procedure involving I ^M(ω) with a stepwise procedure using Schuster's periodogram, to study an approximation of the asymptotic theory for the frequency estimators in finite samples in relation to the proximity and signal-to-noise ratio of the periodic components, and to assess the robustness of I ^M(ω) against autocorrelation in the analysis of mixed spectra. Overall, the results show an improvement of the new method over the classical approach when spectral lines are adjacent. Finally, three examples with real data illustrate specific aspects of the method, and extensions (i.e., unequally spaced observations, trend modeling, replicated time series, periodogram matrices) are outlined.     

长寿风险对教育和退休决策的影响

本文在三阶段世代交叠及两部门经济模型的框架下研究长寿风险对劳动者受教育年限、退休年龄及长期收入的影响。个人的一生分为教育、工作及退休三个阶段,同时劳动者采用经验-工资的倒U型曲线,在此条件下分析劳动者的工作-闲暇决定和消费-储蓄决定。根据模型显示,长寿风险会增加个人的受教育年限、延长退休年龄以及增加劳动者的长期收入。同时,根据模型的敏感性分析,政府对劳动者征收的税率也会对劳动者个人决策产生影响,而且这种影响的程度超过了长寿风险的影响。最后,根据模型的结论提出了相应的政策性建议。