基于密集仓储的烟叶醇化库存取系统设计

传统自动化立体仓库的存取系统,主要设备是货架、输送机和堆垛机,它们在后台仓储软件的管理下,对货物进行存取操作,堆垛机进入立库货物区操作,从安全考虑,货物摆放的空间,要留出足够余量,以便堆垛机行走和装卸货,从多台堆垛机的成本,以及货位摆放的空间效率两方面来看,传统的立体仓库都有改进的必要。探讨在烟叶醇化库中用特殊货架、穿梭板、输送机和一台堆垛机构成新的存取系统,堆垛机在立库口运动,不再进入立库内,而替用穿梭板在立库内装卸货,加上穿梭板特殊的装卸货方式,实现了真正意义上的货物密集存放,节约了立库的设备成本,同时,也能保证立库的自动化管理水平。     

考虑物料、产能和客户优先级三重约束的订单允诺管理问题研究

客户订单允诺管理是在市场全球化的背景下．综合考虑各种资源有限性,对客户的订单给予准确的答复．因而具有很好的应用前号。文章对现有客户订单允诺模型做出改进,在供应链资源即物料和产能双重限制下,加入客户优先级约束,通过建立模型求解,给出合理的客户订单允诺机制。文中不仅定性分析客户优先级．而且将客户优先级量化为客户价值来表示,使该订单允诺管理机制更为有效．更有利于企业的长期可持续发展。     

Selecting Sites for New Facilities Using Data Envelopment Analysis

This paper develops a mathematical programming model for obtaining a best set of sites for planned facilities. The model is concerned with those situations where resource constraints are present. The specific setting for the paper involves the selection of sites for a set of retail outlets, wherein the ratio of aggregate outputs to inputs for the selected set is maximal among all possible sets that could be chosen. At the same time, the model guarantees that the only sets of stores allowable are those for which the available resources are used to the maximum extent possible.     

A note on the determination of A-optimal type block designs under fixed and mixed effects models

In this paper, we consider the problem of estimating a selected set of contrasts between v treatments using a block design consisting of b blocks of size k. Traditionally, the construction of A-optimal block designs for such situations has been carried out assuming a fixed effects model. In this paper, we show that A-optimal designs constructed under a fixed effects model are robust in the sense that these designs have maximal minimal efficiency when considered among all available designs and under all possible mixed effects models. AMS 1991 subject classifications: Primary 62K05; Secondary 62K10     

A Probabilistic Clustering Model for Variables of Mixed Type

This paper develops a probabilistic clustering model for mixeddata. The model allows analysis of variables of mixed type: thevariables may be nominal, ordinal and/or quantitative. The modelcontains the well-known models of latent class analysis as submodels.As in latent class analysis, local independence of the variables isassumed. The parameters of the model are estimated by the EMalgorithm. Test statistics and goodness-of-fit measures are proposedfor model selection. Two artificial data sets show the usefulness ofthese tests. An empirical example completes the presentation.     

A GPS data-based analysis of built environment influences on bicyclist route preferences

This study examines the effects of built environment features, including factors of land use and road network, on bicyclists' route preferences using the data from the city of Seattle. The bicycle routes are identified using a GPS dataset collected from a smartphone application named “CycleTracks.” The route choice set is generated using the labeling route approach, and the cost functions of route alternatives are based on principal component analyses. Then, two mixed logit models, focusing on random parameters and alternative-specific coefficients, respectively, are estimated to examine bicyclists' route choice. The major findings of this study are as follows: (1) the bicycle route choice involves the joint consideration of convenience, safety, and leisure; (2) most bicyclists prefer to cycle on shorter, flat, and well-planned bicycle facilities with slow road traffic; (3) some bicyclists prefer routes surrounded by mixed land use; (4) some bicyclists favor routes which are planted with street trees or installed with street lights; and (5) some bicyclists prefer routes along with city features. This analysis provides valuable insights into how well-planned land use and road network can facilitate efficient, safe, and enjoyable bicycling.     

Reasserting Institutionalist Insights on the Good Society: 30 Years After Petr’s Call for a Mixed Economy

In this research note, I revisit the issues raised by Jerry Petr (1987) in “The Nature and Necessity of the Mixed Economy.” The institutionalist mixed economy is still a sound model for the good society. However, Western industrialized countries have been losing ground on the goals of the mixed economy. The struggle to defend pragmatism over ideological attachment to neoliberalism, has evolved into a distributional struggle that cannot be resolved without institutional change.