Stockouts and Restocking: Monitoring the Retailer from the Supplier’s Perspective

Suppliers and retailers typically do not have identical incentives to avoid stockouts (lost sales due to the lack of product availability on the shelf). Thus, the supplier needs to monitor the retailer’s restocking efforts with the available data. We empirically assess stockout levels using only shipment and sales data that is readily available to the supplier. The model distinguishes between store stockouts (zero inventory in the store) and shelf stockouts (an empty shelf but some inventory in other parts of the store), thereby identifying the cause of the stockout to be either a supply chain or a restocking issue. We find that, as suspected by the supplier, the average stockout rate is much higher than published averages. In addition, stockout rates vary widely between stores. Moreover, almost all stockouts are shelf stockouts. The model identifies stores that may have restocking issues.     

关中-天水经济区经济发展时空差异研究

为了分析关中-天水经济区2007~2015年经济发展时空差异状况,采用变异系数、相对发展率、区位熵等方法进行综合分析。研究表明:2007~2015年,经济区经济发展相对差异逐年减小,整体的发展水平逐年提高;而绝对差异不断扩大,西安、咸阳的经济发展水平相对较高,商洛和天水水平最低。研究期内,西安、咸阳、渭南一直都是经济发达地区,其经济发展相对经济区的平均经济发展速度要迅速,而商洛、天水的发展速度最靠后;西安相对经济区的平均发展速度最快,商洛的经济增长最为明显但发展水平较低。经济区产业结构已经实现了以工业和服务业为主的格局,但发展水平较低;各地市间产业结构差异较大;西安、杨凌的产业结构较为合理,而天水的产业结构需进一步完善。研究结果表明,为促进关中-天水经济区的和谐、高效发展,经济区内各地市在增强自身经济实力的基础上,还应加大相互间的科技、人才和信息交流,充分发展与利用物流、经济信息平台等,推动经济区产业转移与合理布局,逐步缩小地区间发展差异,促进经济区经济社会的健康高效发展。     

基于可达性与经济联系的“一带一路”经济带引力格局划分

对“一带一路”经济带交通网络及国家经济联系的研究是推进沿线国家合作相通的基础,基于 GIS 空间分析技术,运用栅格成本加权距离算法计算“一带一路”的空间可达性,进而引入引力模型,测度中国与“一带一路”沿线国家的经济联系强度,探讨中国与沿线国家的经济联系空间结构及引力格局划分方法。研究认为,“一带一路”中国地区主要节点可达性空间分布具有“通道”型空间特征;西安是“一带一路”起点地区的质心城市,承担了中国境内大部分区域与丝绸之路经济带内国家及地区的联系,沈阳是东北地区中蒙俄经济走廊的重要节点,是中国向北开放的窗口;中国与沿线国家经济联系的区域特征明显,具有强经济联系的国家有孟加拉国、巴基斯坦、印度、俄罗斯等,较强经济联系的国家基本为中亚区域国家,主要是蒙古、哈萨克斯坦、波兰等,欧洲区域的大部分国家与中国的经济联系强度处于中等水平;根据经济联系强度,将“一带一路”经济带分为三大区域:东部地区、中部地区、西部地区,以中蒙俄、中巴、孟中印缅经济走廊以及丝绸之路经济带为纽带,推动区域交通基础设施建设和国际合作,三大区域应该加强优势互补与贸易相通,打造城市群与重要节点城市来提升开放型经济发展水平。     

羌族传统村落的地理分布与空间结构

以羌族传统村落为研究对象,通过对传统聚落与传统村落关系的梳理,明晰传统村落是传统聚落的重要组成部分。根据对羌族传统村落概念的辨析,探究羌族传统村落入选国家级、省级传统村落的情况及其分布,概括羌族传统村落的地理分布特征,发现羌族传统村落相对集中,呈块状或条带状分布,主要沿河流一线展开,干流密集支流稀疏,海拔上具有“高密低疏”的垂直分布特征。从羌族传统村落的空间结构上看,羌族传统村落的空间结构特征表现为数量不多、范围较小、职能单一、规模不大,与人口密度呈正比,村落之间联系有待加强。     

农村非农就业对中国城乡收入不均等的影响——基于中国东中西部面板数据的比较研究

通过对劳动力流动和收入分配的相关研究进行综述,并基于1989～2008年中国各省份的面板数据,采用STATA10.0计量软件,建立联立方程组,运用似不相关方法实证研究农村非农就业对中国区域城乡收入不均等的影响,结果表明：中国农村非农就业在一定程度上扩大了省际间城乡收入不均等;从中国东中西部各地区实证结果看,农村非农就业有利于缩小东部地区的城乡收入不均等,但扩大了中西部地区城乡收入不均等,且农村非农就业对西部地区城乡收入差距的影响程度远高于全国和东中部地区。     

当前城市边缘社区治理优化研究

城市边缘社区是在城市化进程中新出现的社区类型,属于城市与乡村的交汇地带。它既接受城市的辐射带 动,又保留农村的部分特点,具有居民人群结构复杂、社区性质亦城亦乡、居民利益矛盾突出等特征。当前,要优化城 市边缘社区的治理,实现城市边缘社区向成熟的城市社区的转变,面临着社区治理机制不完善的制度困境、社区居民 自治意识淡薄的动力困境、社区治理队伍素质不高的能力困境、社会组织参与社区治理程度较低的资源困境等问题。 要解决当前城市边缘社区治理的多重困境,就必须积极研究和探寻科学有效的城市边缘社区治理对策,通过逐步完善 社区治理体制、优化社区治理队伍整体素质、培育社区精神等措施,推进城市边缘社区治理体制机制的不断优化。     

文明的冲突与选择——《美丽新世界》的空间叙事策略

《美丽新世界》通过空间并置策略,建构起一个先进的后工业文明社会;通过空间对峙策略,描绘了一个传统的弱小的印第安文明社会,与主体文明间形成冲突的张力;通过空间选择策略,讲诉人物因在两个不同的文明间经历空间跨界所遭受的悲剧,展现出不同文明范型之间的冲突与道路选择。整部作品以空间为主要的叙事对象,呈现了异乌托邦小说讲述的空间悲剧,揭示出人类文明未来发展方向的问题。     

Approximate jackknife empirical likelihood method for estimating equations

It is known that the profile empirical likelihood method based on estimating equations is computationally intensive when the number of nuisance parameters is large. Recently, Li, Peng, & Qi (2011) proposed a jackknife empirical likelihood method for constructing confidence regions for the parameters of interest by estimating the nuisance parameters separately. However, when the estimators for the nuisance parameters have no explicit formula, the computation of the jackknife empirical likelihood method is still intensive. In this paper, an approximate jackknife empirical likelihood method is proposed to reduce the computation in the jackknife empirical likelihood method when the nuisance parameters cannot be estimated explicitly. A simulation study confirms the advantage of the new method. The Canadian Journal of Statistics 40: 110–123; 2012 © 2012 Statistical Society of Canada     

Construction and Nonparametric Testing of Orthogonal Arrays through Algebraic Strata and Inequivalent Permutation Matrices

In this article we use a new methodology, based on algebraic strata, to generate the class of all the orthogonal arrays of given size and strength. From this class we extract all the non isomorphic orthogonal arrays. Then, using all these non isomorphic orthogonal arrays, we suggest a method based on the inequivalent matrices permutations testing procedures Basso et al. (2004 Basso , D. , Evangelaras , H. , Koukouvinos , C. , Salmaso , L. ( 2004 ). Nonparametric testing for main effects on inequivalent designs. Proc. 7th Int. Workshop Model-Oriented Design Anal. Heeze, Netherlands, June 14–18 . [Google Scholar]) in order to obtain separate permutation tests for the effects in unreplicated mixed level fractional factorial designs. In order to validate the proposed method we perform a Monte Carlo simulation study and find out that the permutation tests appear to be a valid solution for testing effects, in particular when the usual normality assumptions cannot be justified.     

Marginal methods for clustered longitudinal binary data with incomplete covariates

Many analyses for incomplete longitudinal data are directed to examining the impact of covariates on the marginal mean responses. We consider the setting in which longitudinal responses are collected from individuals nested within clusters. We discuss methods for assessing covariate effects on the mean and association parameters when covariates are incompletely observed. Weighted first and second order estimating equations are constructed to obtain consistent estimates of mean and association parameters when covariates are missing at random. Empirical studies demonstrate that estimators from the proposed method have negligible finite sample biases in moderate samples. An application to the National Alzheimer's Coordinating Center (NACC) Uniform Data Set (UDS) demonstrates the utility of the proposed method.