供应商管理库存的最优购买数量和利润

研究了供应链管理环境下新的库存策略·在传统供应链利润模型基础上,对有确定需求、初始库存和允许库存短缺的一种畅销商品,建立了供应商管理库存的供应链模型,并进一步讨论了供应商管理库存下的采购数量和利润,证明了供应商管理库存供应链的最优购买量比传统供应链的最优购买量要高·同时也证明了实施供应商管理库存会使用户的利润增加,而在优化匹配条件或长期激励下,实施供应商管理库存也会使供应商的利润增加,为双方企业合并其库存提供了理论基础·最后以一个数值算例验证了所得结论·     

供应链多级库存成本优化研究

随着市场竞争的加剧,企业之间的竞争已经演变为了供应链之间的竞争。传统的库存管理主要侧重于单个企业的库存最优,而供应链环境下的库存管理需要最大程度地实现供应链的库存整体最优。本文分析了供应链环境下的库存成本结构和供应链内成本,在此基础上,建立了多个供应商、一个核心制造企业、多个分销商的供应链库存成本模型,在分析遗传算法（GA）原理的基础上,详细说明基于遗传算法的供应链库存成本模型的求解方法,最后通过算例仿真验证了模型和算法的可行性和有效性。     

供应链环境下的一种库存控制模型

供应链环境下的库存管理不同于传统的库存管理，该文主要从多用户和多供应商角度出发，从整体上研究了在供应链的环境下多用户群的库存控制，并建立了相应的控制模型．     

以VMI理论与JMI理论为例浅析供应链库存管理

论述了供应链库存管理的本质,从供应链视角分析了企业供应链库存管理存在的库存控制策略单一、库存信息传递效率较低等问题,介绍了横向的供应商管理库存(VMI)和纵向的联合库存管理(JMI)两种基于供应链管理理论的库存管理策略,详细讨论两种策略的具体步骤、优势、局限性和适用条件,指出在供应链库存管理模式下适合企业库存管理的一些策略方法。     

供应商管理库存模式下库存优化研究

供应链环境下的库存优化是降低整体成本的重要手段，介绍了供应商管理库存（VMI）的基本概念，研究了由供应商和分销商构成的VMI模型下的库存决策模型，并论述了动态规划方法在该问题上的不足之处以及强化学习方法在该问题上的优势，同时介绍了马尔科夫决策模型（Markov）和半马尔科夫决策模型（semi—Markov）的概念，最后通过一个算例对强化学习方法的过程进行了具体的说明。     

精益方式下考虑提前期的制造商发货问题

在精益生产方式下，制造商决定供应链的发货行为．考虑原材料供应商的提前期，建立了制造商的库存相关成本模型．通过最小化库存成本．得到了一个订单周期内最佳的发货次数，并证明了一个订单周期内多次发货能够降低制造商的库存成本．最后，利用数值分析进行了仿真．     

供应链管理环境下的库存策略及模型

供应链管理环境下传统的采购管理模式会导致需求信息的扭曲变异现象,为此可以通过采用供应商管理库存方式,实现各节点企业的战略协作和信息共享,最后建立一个优化库存的模型,并设计一个供应商管理库存系统来验证其优越性。     

基于准时化采购的安全库存模型研究

传统的库存控制模型中,采购提前期的计算大都是从采购商自身成本最小化的角度考虑,而供应链管理的思想要求两者总成本最小化,从而促进供需双方的合作,本文在准时交货的前提下,既考虑供应商持有库存时的成本,又考虑采购商的库存能力和发生缺货下的损失,建立了计算准时交货时间的数学模型,和基于此时间的安全库存模型。     

供应链中库存管理的研究

通过对供应链的本质和供应链流程的研究,分析了供应链中所存在的库存类型,并结合实际提出供应链管理中的种种库存问题,吸收并应用供应链管理下的供应商管理库存(VIM)、联合库存管理(JMI)以及第三方物流等控制方法,提出库存管理的最优化目标——并不是使供应链环节中某一个或几个节点企业的库存最优化,而是整个供应链环节有机地、协调地、一体化库存最优化.针对供应链库存系统中的信息不对称情况作简单分析.     

考虑缺货的供应链联合库存成本分析及收益分配

考虑一个供应商和一个需求方构成的联合库存联盟的成本降低问题.对缺货成本进行了分析,通过建立库存成本分析模型,求得供应链实施联合库存前后库存成本差额,并将成本降低额视为剩余收益.然后基于鲁宾斯坦讨价还价模型对剩余收益进行分配.通过分析,从理论上证明实施联合库存确实降低了供应链系统成本,获得成本降低额,然后将成本降低额有效分配.最后用算例证明该方法的可行性和可操作性.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme