随机补货间隔期的多周期库存优化模型

针对供应商处于相对有利地位,零售商综合考虑各种因素决定他们补货量情况,研究了订货由零售商发起,且补货间隔期不受零售商控制情况下的多周期库存优化问题·在假设允许缺货、补货间隔期是独立同分布的随机变量的前提下,给出了补货间隔期服从一般分布的预期利润函数,通过确定最优补货量来有效地控制库存·在此基础上,又分析了补货间隔期服从两种特殊分布情况,并通过灵敏度分析说明了补货间隔期对其利润的影响·     

基于延期支付与延期交货的最优库存策略研究

文章以由供应商、零售商组成的两阶段供应链为研究对象,供应商给零售商全部延期支付期限,考虑了缺货产品的情形,建立了相应的零售商库存决策模型;通过EOQ模型的分析求解,得出零售商在上述情况下的最优补货周期的判定方法,并通过算例说明了模型的有效性。     

一类变质性物品在考虑货币时间值和通货膨胀率时的最优生产库存策略

作者在考虑货币时间值和通货膨胀率的情况下,讨论了需求是时间的连续函数、允许缺货且缺货完全回补、变质率为常数、补货率有限的变质性物品在有限计划期内的生产-库存策略,同时证明了最优生产-库存策略的存在唯一性,并给出了求最优策略的算法和算例.     

需求与库存量相关及学习曲线的退化性产品最优订购策略

针对需求与库存量相关的退化性产品,假设退化率为常数而需求率为库存量的函数,考虑数量折扣与学习曲线,同时考虑了购买成本与时间和数量的关系,提出了有限计划期需求与库存相依的退化性产品库存模型.在不允许缺货、完全缺货待补、部分缺货待补且待补率与等待补货时间相关等三种情况下,以库存总成本最小化为研究目标提出了求解算法并进行了数值算例验证及敏感性分析.     

供应链中基于延期交货的批量订货策略

对1个卖方、2个买方的供应链系统,买方的地位相等,其需求为固定的常量.在通常的数量折扣模型的基础上允许缺货或延期交货,并以此来研究卖方定价对买方订货策略的影响,但先决条件是不损害供应链所有成员的利益.从其结果看,适当时长的缺货或延期交货对卖方以及买方都有很大的好处,与没有缺货的情形相比,虽然某些时候订货数量少了一些、价格高了一些,但链中所有成员的成本节省却大大增加.     

时变需求下部分欠拨待补的易损耗品最优批量库存模型

为使传统库存问题中缺货的假设与企业实际情况相符,重新定义需求率与部分欠拨待补率为时间的函数,并考虑因缺货而引发的机会成本,建立了时变需求的易损耗品库存模型.在模型构建过程中证明了最小化总成本的最优解也能将总利润最大化,且最优补货策略具有单调的特殊性质.此外,考虑最初补货周期中的各项成本关系给出了提高模型求解效率的简单启发算法,并通过算例验证了模型和算法的有效性.     

允许缺货且缺货量部分拖后的供应商管理库存

供应商管理库存的主要目标是使供应链中所有成员的总成本尽可能地降至最低,使总利润尽可能地达到最大。在不允许缺货、允许缺货但缺货量完全拖后等VMI模型研究的基础上,构建了考虑一个供应商和多个不同的订货商、订货商允许缺货且缺货量部分拖后的VMI模型。并结合算例,验证了使用该模型制订库存策略的有效性。     

含部分延期交货的多级库存模型

考虑到多级库存管理是供应链管理的重要形式,研究了外部需求确定环境下的允许缺货且部分延期交货的多级库存系统管理问题,建立了含缺货费用和销售损失费用的费用模型,推导出了最优订货策略的算法。算例分析表明,延期交货率增大,最小费用减小;销售损失成本增大,最小费用增大。     

生产-分销物流系统中考虑缺货成本时的存贮路径问题研究

文章建立了一个制造商与多个分销中心的一体化生产-分销系统模型.模型假设制造商有一个固定的生产周期,将各分销中心的补货频率作为决策变量,考虑了整个生产周期中分销中心的存贮成本、运输成本、车辆固定启动成本、补货成本以及缺货成本,使得总成本最小以确定最优的配送方案.最后,通过算例重点分析了缺货成本对于决策以及总成本的影响.     

基于可控提前期的库存优化模型

研究随机需求下连续盘点的库存控制问题.在满足提前期可控和服务水平约束条件下建立库存优化模型.模型允许缺货,且部分缺货可以延期交货,部分缺货造成销售损失;并假定运输成本与运输量线性相关,同时零售商的提前期是可以控制的,并且缩短提前期会造成一定的赶工成本.从理论上论证模型最优解存在条件,设计求解最优订货量、最优提前期、最优...     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has