唐代西受降城、天德军的置废和建制沿革考述

为了应对北方游牧民族的威胁,唐朝在河套地区先后修建了西受降城和天德军等两座军事城镇。两城设立之初,在唐朝的北疆防御体系中占有重要的地位。西受降城建成后不久即因水患而遭废弃并在旧址以东另筑新城,天德军也因在安史之乱中遭到破坏而一度被废弃并移至西受降城。后来设立天德镇专门负责河套西部地区的防务,其辖区几经变化,最后领有天德...     

基于区位商法的成渝城市核心竞争力评价研究

文章以国家经济发展指标作参照,选取成渝两市近几年经济发展的重要指标为研究对象,与上海、广州、北京三市进行比较分析,依据区位商法（LQ）理论建立数学模型,并利用偏离指数法进行二次量化研究,从而构建城市核心竞争力评价标准;根据竞争力评价结果总结出成渝经济发展的优势条件以及当前所面临的核心问题;最后针对核心问题从城市的物质特性、精神特性以及城市价值角度提出加强成渝城市核心竞争力的五项对策。     

我国会展场馆的区位选址分析

作者分析了我国会展场馆区位主体的区位需求,界定了会展场馆区位条件的含义,然后归纳和总结了我国会展场馆现实区位条件规律,通过对区位条件和会展场馆效益的相关性分析,提出了我国会展场馆未来区位调整的方向和策略。     

On expected sample range from heterogeneous symmetric distributions

It is shown that for independent (but not necessarily identically distributed) random variables with distributions symmetric about the respective medians (means), the expected value of the sample range is a minimum when these means are all equal.     

On Progressively Type-II Censored Two-parameter Rayleigh Distribution

Recently, Rayleigh distribution has received considerable attention in the statistical literature. In this article, we consider the point and interval estimation of the functions of the unknown parameters of a two-parameter Rayleigh distribution. First, we obtain the maximum likelihood estimators (MLEs) of the unknown parameters. The MLEs cannot be obtained in explicit forms, and we propose to use the maximization of the profile log-likelihood function to compute the MLEs. We further consider the Bayesian inference of the unknown parameters. The Bayes’ estimates and the associated credible intervals cannot be obtained in closed forms. We use the importance sampling technique to approximate (compute) the Bayes’ estimates and the associated credible intervals. For comparison purposes, we have also used the exact method to compute the Bayes’ estimates and the corresponding credible intervals. Monte Carlo simulations are performed to compare the performances of the proposed method, and one dataset has been analyzed for illustrative purposes. We further consider the Bayes’ prediction problem based on the observed samples, and provide the appropriate predictive intervals. A data example has been provided for illustrative purposes.     

On the location of new facilities for chain expansion under delivered pricing

We study the problem of locating new facilities for one expanding chain which competes for demand in spatially separated markets where all competing chains use delivered pricing. A new network location model is formulated for profit maximization of the expanding chain assuming that equilibrium prices are set in each market. The cannibalization effect caused by the entrance of the new facilities is integrated in the objective function as a cost to be paid by the expanding chain to the cannibalized facilities. It is shown that the profit of the chain is maximized by locating the new facilities in a set of points which are nodes or iso-marginal delivered cost points (points on the network from which the marginal delivered cost equals the minimum marginal delivered cost from the existing facilities owned by the expanding chain). Then the location problem is reduced to a discrete optimization problem which is formulated as a mixed integer linear program. A sensitivity analysis respect to both the number of new facilities and the cannibalization cost is shown by using an illustrative example with data of the region of Murcia (Spain). Some conclusions are presented.     

Simultaneous estimation of ordered parameters

The problem of estimating ordered parameters is encountered in biological, agricultural, reliability and various other experiments. Consider two populations with densities f₁(x₁-ω₁) and f₂(x₂-ω₂) where ω₁#ω₂. The estimation of ω₁,ω₂) with the loss function, the sum of squared errors, is studied. when f_i is the f_i(,_i,,_i ²) density with ,_i known, i=1,2; we obtain a class of minimax estimators. When ω₁ #ω₂ we show some of these estimators are improved by the maximum likelihood estimator. For a general f_i we give sufficient conditions for the minimaxity of the analogue of the Pitman estimator.     

Classification of dichotomous and continuous variables with incomplete samples

This Article Considers the problem of classifiying an observation consisting of both binary and continuous variables based on two general incomplete training samples one from each of the two given populations. The location linear model adopted by krzanowski 1975 forms the basis of our inverstigation. For a given location, When the common dispersion matrix as Well as the corresponding cell probabilities for the underlying populations are known, exact distribution of the conditional maximum likelihood classification rule is derived. The overall error rate can be obtained and is based on linear cominations of independent non– Chi– Distributions. large sample result for the case where the cell probabilities are unknown is also available.     

SUB-SAMPLE MANN–WHITNEY–WILCOXON TEST

ABSTRACT

This paper presents a class of sub-sample rank-sum statistics to test the stochastic ordering between two distributions. The proposed class includes as special case the min–max test of Öztürk.[1] Öztürk, Ö. 2001. A Generalization of Ahmad's Class of Mann–Whitney–Wilcoxon Statistics. Austrl. and New Zealand J. Statist., 43: 67–74.  [Google Scholar] It is shown that the asymptotic distribution of the test statistic is normal and its Pitman asymptotic efficiency is as good as or higher than the competitors in the class of sub-sample Mann–Whitney–Wilcoxon statistics.     

Linear Estimators and Predictors Based on Generalized Order Statistics from Generalized Pareto Distributions

Linear estimation and prediction based on several samples of generalized order statistics from generalized Pareto distributions is considered. Representations of best linear unbiased estimators (BLUEs) and best linear equivariant estimators in location-scale families are derived, as well as corresponding optimal linear predictors. Moreover, we study positivity of the linear estimators of the scale parameter. An example illustrates that the BLUE may attain negative values with positive probability in certain situations.