改进遗传算法求解带模糊时间窗冷链配送问题

为优化冷链物流配送路径,降低配送成本、提高客户对产品送达时间的满意度水平是冷链物流的关键。考虑到冷链物流承载的货物具有一定的特殊性且对温度的要求较高,提出在冷链物流配送中设定模糊时间窗反映顾客满意度。建立了运输成本、货损成本、时间成本等配送成本最小化和以模糊时间窗进行量化客户满意度最大化的多目标优化模型,采用改进遗传算法求解带模糊时间窗冷链配送问题。通过算例分析,验证了模型和算法的有效性与研究的实用价值。     

基于路况的医药冷链物流配送路径优化

基于传统的医药冷链物流配送模型,在考虑道路通行状况对模型求解最优路径影响的基础上,建立了以综合成本为目标函数的配送模型.同时,将实际配送情况进行参数化数学建模,并通过一个数值算例,使用蚁群算法求解考虑道路通行状况的配送模型与未考虑道路通行状况的配送模型,将求解结果进行比较分析.结果表明:考虑路况条件的配送模型求解得到的最优路径比未考虑路况条件的配送模型求解得出的最优路径效果更优,综合成本降低11.96％,考虑路况条件的医药冷链物流配送模型具有更大的现实意义.     

时变路网环境下多温冷链配送路径优化研究

【目的】生鲜产品在冷链物流配送过程中的新鲜度及货损成本与配送行程所耗时间密切相关,而配送车辆在城市路网中不同时段行驶的速度不同,基于此在考虑了道路交通状况的时变路网特性之后研究配送的优化问题。【方法】针对时变路网环境下的多温区产品配送车辆调度问题,考虑载重质量与车厢容积及时间窗约束,建立由运输成本、货损成本及制冷成本构成的目标为总配送成本最小的数学优化模型,设计基于模拟退火算法的求解程序,并用MATLAB对实例进行求解。【结果】与以往研究中用平均速度方法求解出时间变量的方法不同,通过时变路网理论及模型求解,验证了时变路网环境下冷链配送路径优化模型及算法的有效性。【结论】结合时变路网,改进了货损成本中腐败函数的时间变量求解方法,刻画了各配送车辆每完成一个客户的配送后,车辆剩余货物在余下配送时间里货损成本继续发生的动态过程。     

考虑客户满意度的车辆路径优化及其算法研究

针对当前车辆路径问题中较少考虑客户满意度的情况,构建了基于模糊时间窗的车辆到达时间满意度函数和货物运输时长满意度函数,以最大化客户满意度和最小化配送总成本为目标建立VRPCCS数学模型.为了求解该问题,考虑到传统遗传算法存在依赖初始解、收敛速度较慢、容易陷入局部最优等缺点,设计改进的遗传算法与大规模邻域搜索算法相结合的混合算法进行求解,通过选取算例并与传统遗传算法进行对比,验证了模型和算法的可行性和有效性.实验仿真结果表明考虑客户满意度的物流配送方式不仅能够有效提升客户满意度,也能够降低物流企业配送成本以及车辆空载率,对于物流企业的车辆配送路径决策具有一定的参考意义.     

电子商务配送的跨区域VRP模型及其启发式算法

传统的基于分区策略的配送模式已不能满足电子商务物流配送业务的要求,采用将多个配送区域联合、沿途多次补货的配送策略可有效地解决上述矛盾,而车辆路径问题是该配送策略的一个重要组成部分。在说明了模型的假设条件后,建立了基于区域联合策略的VRP(veh icle rou ting prob lem)模型,开发了一种基于几何分析的启发式算法,采用二次搜索、分批插入的办法确定补货点,从而得到沿途多次补货的配送路径,最后用数值算例对模型和算法进行了数值演算。     

基于多目标优化的渔获物冷链配送

远洋渔获物从港口出发被运输至各个需求市场的过程中,冷链配送方案的规划对于提高运输效率与降低成本投入等方面都起着至关重要的作用.为了提升配送效率和降低配送成本,根据渔获物受配送时间和环境温度等影响发生不同程度耗损的特点,引入低温能耗与需求时间窗等成本要素,建立了以配送服务时间最短和成本最小为目标的多目标冷链配送模型.根据所建立模型的决策变量,设计相应的遗传算法求解并结合某港口配送中心的算例进行分析.结果表明:本文提出的冷链物流配送模型可以为企业实现较少配送时间与较低成本,进而验证了模型的可行性.     

考虑客户满意度的物流公司终端配送线路优化

【目的】针对物流公司终端配送线路优化问题,考虑客户满意度以及退货情况对配送方案的影响,力图优化配送线路,提高客户满意度。【方法】分析不同客户(收货、发货、退货)的特点,建立了基于软时间窗的顾客满意度函数,并构建了以配送总成本最低为目标的混合整数规划模型,进一步根据终端配送问题的特征设计了求解模型的模拟退火算法,最后通过Matlab软件和具体算例,进行模拟计算。【结果】通过比较有无考虑客户服务时间的两种情况的求解结果,验证了该算法的有效性和实用性。【结论】考虑终端配送过程中客户满意度以及退货情况的发生,可以减少配送成本、节约配送时间、提高客户满意度,极大地提高物流公司竞争力。     

基于新版GSP标准的医药冷链物流配送优化

随着我国医药行业、物流行业的不断发展,医药冷链物流市场发展潜力巨大.分析了国内外医药冷链物流管理标准,以新版产品供应规范(good supply practice,GSP)标准为基础,总结了医药冷链物流配送问题的关注点,并建立了医药冷链物流配送优化模型.该模型以配送成本最小为目标,在约束条件中考虑了供需平衡、中转站容量以及不同周期的最大运输量等问题.以实例说明了改进后的配送方案符合新版GSP标准的要求且成本更低,为构建高效率、低成本和低损耗率的医药冷链物流体系提供了一定的参考依据.     

带时间窗的蓄冷式多温共配冷链配送问题研究

【目的】随着社会货物多样性需求的增大,多温共配不断发展,而蓄冷式 MTJD 又是冷链物流行业中一个新型的概念。【方法】针对蓄冷式 MTJD 模式下的多温度需求货物的配送调度问题,考虑时间窗约束,建立了以总配送成本最小为目标的混合整数规划模型,其中总配送成本主要包括蓄冷箱成本、车辆运输成本和惩罚成本等。针对该模型,设计了适合求解蓄冷式 MTJD 模型的染色体编码方式以及遗传算子,对算例进行求解。并通过利用 Cplex 对算例重新编写代码、求解,验证了遗传算法的有效性。【结果】蓄冷式 MTJD 的各个区间的温度可以根据需求自由地设置,保温性能也明显优于机械式冷冻车厢区隔式 MTJD 。【结论】蓄冷式 MTJD 在配送成本上相较于传统冷链配送模式以及机械式冷冻车厢区隔式 MTJD 具有明显优势,是一种值得推广的冷链物流配送模式。
     

生鲜品多中心区域协作半开放式配送路径研究

针对生鲜产品区域配送问题,在新物流理念下,建立了区域协作下多中心半开放式配送路径.鉴于生鲜品配送的独特性,将时间窗及满意度考虑在内,构建在时间惩罚、满意度指标及路径约束条件下的成本优化模型.结合A生鲜企业数据,设计了一种改进的自适应遗传算法与变邻域搜索算法相结合的混合算法解决问题.通过仿真实验证明模型合理性以及算法实效性.实验表明,区域协作下多中心半开放式配送方案对比各区域独立封闭式配送方案具有改进性,提高了物流配送的效率,降低成本同时保证高客户满意度,有助于生鲜配送企业整体发展.并在此基础上,对生鲜配送企业进一步发展提出建议.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

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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