CROSS‐DOCKING AND ITS IMPLICATIONS IN LOCATION‐DISTRIBUTION SYSTEMS

Cross‐docking replaces traditional warehousing, enabling continuous flow of items without storage. Here we model location‐distribution networks, that include cross‐docking facilities, to obtain the latter's impact on the supply chain. We formulate optimization models to minimize total cost in three multi‐echelon networks, each model generalizing the preceding one. The first includes a single manufacturer, one product type, and multiple customers. Cross‐docks are to be located between origin and destinations. Besides solving optimally, a tool for quantitative analysis of direct‐shipment decisions is developed. The second model considers more than one product: We determine a cost‐effective sequence of items for indirect shipment (via cross‐docks). Finally, in a network with multiple origins, optimal solutions are obtained for 40 medium‐sized and larger examples.     

EXPRESSING INVENTORY CONTROL POLICY IN THE TURNOVER CURVE

Estimation of the inventory level for an entire class of items is a valuable time saver when control of inventories at the aggregate level, rather than the item level, is of interest. Inventory approximation by location in supply chain network configuration and evaluation of inventory control policy shifts, are two examples of application. In this article, various popular inventory policies are related to a general function known as an inventory turnover curve that expresses inventory levels from the combined demand of multiple items. By knowing some basic item characteristics of representative items in a product class, the type of inventory policy being used, and the current aggregate inventory level, an inventory turnover curve can be constructed. This resulting turnover curve can be used to estimate inventory levels within 4.6%, on the average, of theoretically predicted ones.     

Symmetry and order in the portfolio allocation problem

Summary. This research studies the role of multivariate distribution structures on random asset returns in determining the optimal allocation vector for an expected utility maximizer. All our conclusions pertain for the set of risk averters. By carefully disturbing symmetry in the distribution of the, possibly covarying, returns, we ascertain the ordinal structure of the optimized allocation vector. Rank order of allocations is also established when a permutation symmetric random vector is mapped into the returns vector through location and scale shifts. It is shown that increased dispersion in the vectors of location and scale parameters benefit, ex-ante, investors as does a decrease in the rank correlation coefficient between the location and scale parameter vectors. Revealed preference comparative static results are identified for the location and scale vectors of asset returns. For most issues addressed, we arrive at much stronger inferences when a safe asset is available. Received: August 8, 2000; revised version: January 8, 2001     

Spatial determinants of Japanese FDI in China

Research on foreign direct investment in China has spawned an increasingly large literature. Whilst regional cleavages with respect to the distribution of foreign direct investment (FDI) are acknowledged, empirical research on the spatial determinants of FDI in China has been limited. Furthermore, research on the spatial determinants of home country FDI in China has thus far been neglected due to difficulties in accessing the appropriate data. The objective of this paper is to examine the spatial determinants of Japanese direct investment in China by using an econometric model. To that purpose, a dataset is created from the Toyo Keizai directory on the overseas activities of Japanese companies. The results show that tertiary education, inland waterways, as well as coastal location are positive and significant determinants of Japanese investment in China.     

PLANNING MULTIPLE LOCATION INVENTORIES

Supplying customer demand from comparable alternate inventory locations when an item is out of stock at its primary stocking point creates a virtual inventory for that item. The expectation is that if more inventories can be drawn upon, the inventory for an item would be lower, the fill rate would be higher, or both. While generally true that safety stocks will be lower, regular stocks, on the other hand, may rise with such cross filling of demand. In this study, a methodology is developed that balances the cross filling effects on both regular and safety stocks for determining whether an inventoried item should be cross‐filled. An example and guidelines are given to show how the methodology can be simplified and applied in practice.     

Planning food services for a campus setting

Providing appropriate food services in a campus setting is increasingly important due to more demanding customers and because clients have less time to go off-campus when they need to eat. Using a university campus as an example, this research looks at customer satisfaction with existing food services and explores various methods for determining where to locate new facilities. This campus currently has great needs for additional food services, and it is shown clearly where additional food services are required. Also, the methods used are compared in terms of their effectiveness in finding the solution.     

基于M／N检测的高距离分辨率信号的速度补偿

本文介绍了进步频率高距离分辨率信号，分析了运动速度对该高距离分辨率信号的影响，提出了基于多散射中心联合检测（Ｍ／Ｎ检测）的速度环路补偿方案。该方案使用多距离单元的联合检测完成高距离分辨率信号的最佳速率补偿，同时进一步降低目标的虚警概率，提高了目标的发现概率。     

Production-location decision and free entry oligopoly: A correction

This paper shows that there is no interior solution in Mai–Hwang's 1992 oligopolistic location model with free entry when the production function exhibits constant or decreasing returns to scale. The comparative static results of the impact of a demand change on the location decision only apply to the case where the production function exhibits increasing returns to scale. It re-examines the impact of a demand change on the location decision of an oligopolistic firm and corrects the propositions derived by [C.C. Mai, H. Hwang, Production-location decision and free entry oligopoly, Journal of Urban Economics 33 (1992) 252–271. Reprinted in: M.L. Greenhut, G. Norman (Eds.), The Economics of Location, vol. I: Location Theory, Edward Elgar, Aldershot, 1995].     

西部大开发战略与武汉城市功能的发挥

西部大开发战略的实施 ,为武汉这个中部特大中心城市的发展提供了机遇 ,如何顺势起飞 ,关键在于武汉中心城市功能的发挥。处于中部承东启西 ,九省通衢 ,基础强劲的武汉特大中心城市功能的发挥 ,也会有力地促进西部大开发战略的落实。武汉立足于其区位综合优势 ,从集散功能、生产功能、管理功能、服务功能、创新功能发展出发 ,借西部大开发之势重构和强化其金融商贸中心功能、交通枢纽功能、通讯信息中心功能、科技教育文化中心功能、生产和服务中心功能 ,是武汉发展和西部大开发的双赢策略。     

动态比较优势与中国目标产业选择实证分析

通过动态比较优势的理论模型，可揭示后进国家政策介入的必要性和有效性；采用独立随机增量过程马尔可夫链方法，可对中国制造业动态比较优势进行经验验证和预测。结果显示，弱比较劣势产业是目标产业。该些产业的优势状态保持不变或上移的概率高达80％以上，表明它们具有较大的潜在比较优势。