On the two-sided power distribution

This paper concerns a two-parameter two-sided power distribution introduced by van Dorp and Kotz on the interval [0,1]. We introduce a reformulated two-sided power distribution (with the same number of parameters) and provide evidence to prove that it is more flexible than the one suggested by van Dorp and Kotz. We derive various properties of the new distribution as well as provide several hitherto unknown properties of the distribution due to van Dorp and Kotz. We also discuss estimation by the method of moments and the method of maximum likelihood.Received September 2003     

On the generalized Poisson distribution

We use Euler's difference lemma to prove that, for θ > 0 and 0 ≤λ < 1, the function P _n defined on the non-negative integers by
P _n (θ, λ) = [θ(θ + n λ) ^{n −1}/ n !]e^{− n λ−θ}
defines a probability distribution, known as the Generalized Poisson Distribution.     

On the distribution of city sizes

The city size distribution in many countries is remarkably well described by a Pareto distribution. We derive conditions that standard urban models must satisfy in order to explain this regularity. We show that under general conditions urban models must have (i) a balanced growth path and (ii) a Pareto distribution for the underlying source of randomness. In particular, one of the following combinations can induce a Pareto distribution of city sizes: (i) preferences for different goods follow reflected random walks, and the elasticity of substitution between goods is 1; or (ii) total factor productivities of different goods follow reflected random walks, and increasing returns are equal across goods.     

浅论配送半径的计算方法

配送处于供应链的末端,是上游所有工作的承继者,也是供应链最终价值的实现者之一,随着市场需求个性化、多样化、即时化的加剧,供应链与供应链之间的竞争主要聚焦于配送环节,而确定一个科学精确的配送半径,是实现配送中心合理规划和高配送质量的重要保证,文中阐述了影响配送半径的主要因素,给出了计算配送半径的基本方法,引出了保留半径这一新概念,使配送半径的计算更加精确。     

On the distribution of the sample autocorrelation coefficients

Sample autocorrelation coefficients are widely used to test the randomness of a time series. Despite its unsatisfactory performance, the asymptotic normal distribution is often used to approximate the distribution of the sample autocorrelation coefficients. This is mainly due to the lack of an efficient approach in obtaining the exact distribution of sample autocorrelation coefficients. In this paper, we provide an efficient algorithm for evaluating the exact distribution of the sample autocorrelation coefficients. Under the multivariate elliptical distribution assumption, the exact distribution as well as exact moments and joint moments of sample autocorrelation coefficients are presented. In addition, the exact mean and variance of various autocorrelation-based tests are provided. Actual size properties of the Box–Pierce and Ljung–Box tests are investigated, and they are shown to be poor when the number of lags is moderately large relative to the sample size. Using the exact mean and variance of the Box–Pierce test statistic, we propose an adjusted Box–Pierce test that has a far superior size property than the traditional Box–Pierce and Ljung–Box tests.     

On the optimal distribution of income among cities

In a competitive land market, different consumers will bid differing amounts to be located at one or another points in space. This article demonstrates that consumers fare better by competing in land markets where other competitors have different bid structures than they. Since income has a strong effect on one's bidding, the paper formally proves that poor consumers would, ceteris paribus, prefer to locate in cities with rich consumers and vice versa. With respect to the market for urban land, the inference is that cities heterogeneous in income are preferred by all to homogeneous ones.     

On the distribution of a distance function on the sphere

Summary The distribution of the square of the distance between a random point and a fixed point on ap-dimensional unit sphere when (i) the two points lie on the whole sphere and (ii) the two points lie in the positive quadrant, has been derived, assuming that the random point is distributed proportionally to exp (ky ₁), wherek is a concentration parameter. Then-th order moment in both cases is also obtained.     

On a recent characterization of the bivariate normal distribution

Summary A recent characterization of the bivariate normal distribution is recalled and a few remarks regarding this characterization and its extension to the multivariate case are given.     

On the non-null distribution ofWilcoxon's signed rank test

Summary The properties of theWilcoxon signed rank sum testW ⁺ [Wilcoxon, 1945] for the hypothesis of symmetryH _o are discussed for alternativesH toH _o. The probability generating function and cumulant generating function ofW ⁺ are derived and a limiting form of the distribution is determined.     

On testing the correlation coefficient of a bivariate normal distribution

Summary Here we propose two tests for testing in the bivariate normal population assuming that the ratio of the variances in it is known. The first test (U.M.P.U.) is derived by using the Neyman-Pearson lemma, whereas the second test is obtained through testing the scale parameter of the Cauchy distribution. The powers of the first and second tests are compared with a well-known test, based on the sample correlation coefficient for small and large samples respectively.     

浅析输配电线路的安全运行管理

文章将根据电网运行多年总结出来的宝贵经验,对输配电线路的安全运行管理问题进行深入的阐释与分析。     

On a distribution of Jasso and Kotz

Explicit expressions are derived for the moments and the Gini coefficient of the ring-exponential distribution introduced by Jasso and Kotz ( Statistica Neerlandica , 61 , 2007, 305–328).     

On a Morgenstern-type bivariate gamma distribution

Summary In this paper a Morgenstern-type bivariate gamma distribution has been studied. Its moment generating function has been derived. The distribution of the product and quotient are derived in terms of the modified Bessel function. The results for the independent case follow as special cases. Further the regression function has been analysed, in terms of its deviation from linear regression function.This research was initiated while the first author was a U.N. Consultant under the Statistical Training Program for Africa, visiting the University of Ghana.     

On the predictability of the distribution of excess returns in currency markets

This paper investigates the predictability of foreign exchange (FX) volatility and liquidity risk factors on returns to the carry trade, an investment strategy that borrows in currencies with low interest rates and invests in currencies with high interest rates. Previous studies have suggested that this predictability could have been spuriously accounted for due to the persistence of the predictors. The analysis uses a predictive quantile regression model developed by Lee (2016) that allows for persistent predictors. We find that predictability changes remarkably across the entire distribution of currency excess returns. Predictability weakens substantially in the left tail once persistence is accounted for, implying a moderate negative predictive relation between FX volatility risk and carry trade returns. By contrast, it becomes stronger in the right tail. Furthermore, we provide evidence that FX volatility risk still dominates liquidity risk after controlling for persistence. These findings suggest that the persistence of the predictors needs to be taken into account when one measures predictability in currency markets. Finally, out-of-sample forecast performance is also presented.     

论连锁商业的配送中心建设

连锁经营和物流配送都是市场经济发展到一定阶段的产物，连锁经营把传统流通体系中相互独立的商业职能有机地结合在统一的经营中，实现了采购、配送、批发、零售的一体化。配送是伴随着大生产、大流通而出现一种完成资源配送的方式。连锁经营的出现为建立物流配送中心创造了有利条件，同时物流配送中心的建立促进了连锁经营的发展，两相辅相成，互相促进，相互发展是一个有机的整体。     

On the asymptotically uniform distribution modulo 1 of extreme order statistics

Let (X_m)∞₁ be a sequence of independent and identically distributed random variables. We give sufficient conditions for the fractional part of rnax (X₁., X_n) to converge in distribution, as n ←∞ to a random variable with a uniform distribution on [0, 1).