物流配送中心选址数学模型和算法问题研究

在对物流配送中心选址问题进行理论综述和分析的基础上,以综合运输成本最低为基本约束条件构建了选址的数学模型,并通过启发式算法求得了模型的最优解,得出了各工厂对各物流配送中心以及物流配送中心到各货物配送需求点的最佳配送数量,并通过一个实例对模型进行验证和分析,结果证明该模型和算法可以有效优化物流系统的运作和提高运行效益.     

网络购物环境下物流配送的瓶颈及其出路

当今世界,网络购物的盛行使得配送类业务呈现出了高速增长的态势。然而,由于网购环境的不成熟、不规范,在物流配送方面仍然不可避免地存在诸多问题,并制约了网络购物进一步地发展。文章首先阐述了网络购物在我国的发展现状,然后分析了网购环境下配送存在的问题,最后提出网购配送未来的发展出路。     

精益管理在供应链的研究

文章围绕利用精益管理解决建筑行业当时供应链分散、缓慢等问题,通过现代成型配送理念和精益库存,将现代信息流贯穿整个供应链,以求达到高效率、低成本、零库存的目标,最大程度为企业赢取利润。     

无线电通信仿真的数据分布管理

随着无线电行业的高速发展,无线电通信仿真的数据分布的管理也在提升。文章利用基于无线电通信的分布式仿真技术来建立HLA的对抗仿真环境,这是解决无线电通信系统以及对抗仿真和效能评估问题的最佳途径。     

关于新经济条件下的中国工会组织及其工作思路的思考

文章从经济和历史两个维度,分析了中国特殊劳动关系下的工会工作,阐述了重视并加强工会工作的必要性和现实性,以及在对待工会问题上所存在的一些缺憾和亟待解决的问题。从而折射出中国特色市场经济条件下工会工作的现实复杂性与艰巨性,进而推演出新形势下工会组织的准确定位与工作思路:从企业的国际性发展规律和社会的实际需要来理顺劳资关系;提高工会干部的综合素质是理顺劳动关系的根本。     

基于DEA的B2C电子商务配送模式的选择

分析目前B2C电子商务企业物流配送模式选择存在的问题及各种配送模式的特点,确定B2C电商企业选择配送模式的主要指标。采用数据包络分析（DEA）方法,展示如何选择适合B2C电子商务企业的配送模式。     

Re-examining the Fisher Effect: An Application of Small Sample Distributions of the Covariate Unit Root Test

Abstract

This article employs the covariate unit root test proposed by Elliott and Jansson to investigate the stationarity properties of real interest rates. Instead of blindly trusting the asymptotic distribution of the test, we extend Rudebusch's method to estimate its finite sample distributions under the null and alternative hypotheses. With these distributions, we can obtain the probabilities that the test statistic comes from the null and alternative hypotheses, and quantify the asymptotic size as well as the test power for each specific series. Our simulation experiments show that first, due to the higher power raised by the inclusion of covariates, the test can overwhelmingly reject the unit root null for the 16 industrialized countries; secondly, the Ng and Perron tests deliver lower powers in most countries, and thus lead to the false conclusion of non-stationary real interest rates. Finally, allowing for multiple endogenous breaks in the real interest rates provides only stationary evidence in half of the 16 countries.     

Environmental efficiency and its distribution dynamics in Chinese cities

ABSTRACT

This paper investigates environmental efficiency and its distribution dynamics in Chinese cities. The analyses are applied the meta-frontier data envelopment analysis and the continuous dynamic distribution approach together with panel data of 286 Chinese cities at the prefecture and above-prefecture levels. The results show that during the period of 2002–2011, the average environmental efficiency in Chinese cities is well below the production frontier. The coastal cities show better performance than the central and western cities; large and extra-large cities are more efficient than small and medium cities; and the environmental efficiency for the ‘key’ cities is slightly better than that for the ‘non-key’ cities. The spatial dynamic distribution analyses indicate that the environmental efficiency of Chinese cities tends to converge. To improve environmental efficiency in the future, the government should pay more attention to the central cities, medium and large size cities in western China, and the non-key cities.

Abbreviations: CPI- Consumer price index; DEA- Date envelopment analysis; DMU- Decision making unit; GDP- Gross domestic product; GMI -Group- frontier managerial inefficiency; IPCC- Intergovernmental Panel on Climate Change; MTR- Meta- technology gap ratio; NTP- Net transition probability; PAA- Prefecture and above-prefecture levels; PIM Perpetual inventory method; SFA Stochastic frontier analysis; TGI Technology gap inefficiency     

Towards a better measure of income inequality in Indonesia

Indonesia has experienced significant economic growth in recent years (on average, 5% in 2000–08), but many people are still living in poverty. Income inequality, as measured by the official Gini coefficient, has also increased. This paper evaluates household income and income inequality in Indonesia, assessing both market and non-market income to reach a more accurate measure of how actual income affects living standards. We find that if household income considers non-market income, income distribution is significantly more balanced, the coefficient of income inequality falls from 0.41 to 0.21 and the income share of the population's poorest deciles increases more than fivefold. The results suggest that market income alone is a misleading measure of income distribution in Indonesia.     

Exact confidence sets and goodness-of-fit methods for stable distributions

Usual inference methods for stable distributions are typically based on limit distributions. But asymptotic approximations can easily be unreliable in such cases, for standard regularity conditions may not apply or may hold only weakly. This paper proposes finite-sample tests and confidence sets for tail thickness and asymmetry parameters (α$\alpha$ and β$\beta$) of stable distributions. The confidence sets are built by inverting exact goodness-of-fit tests for hypotheses which assign specific values to these parameters. We propose extensions of the Kolmogorov–Smirnov, Shapiro–Wilk and Filliben criteria, as well as the quantile-based statistics proposed by McCulloch (1986) in order to better capture tail behavior. The suggested criteria compare empirical goodness-of-fit or quantile-based measures with their hypothesized values. Since the distributions involved are quite complex and non-standard, the relevant hypothetical measures are approximated by simulation, and p$p$-values are obtained using Monte Carlo (MC) test techniques. The properties of the proposed procedures are investigated by simulation. In contrast with conventional wisdom, we find reliable results with sample sizes as small as 25. The proposed methodology is applied to daily electricity price data in the US over the period 2001–2006. The results show clearly that heavy kurtosis and asymmetry are prevalent in these series.