电子商务环境下考虑退货的选址库存问题模型与算法

选址库存问题(location inventory problem, LIP)是物流系统集成的经典问题之一,也是企业需要面对的管理决策难题。本文考虑在电子商务环境下无质量缺陷的退货商品可简单再包装后重新进入销售市场这一现实情况,对设施选址和库存控制进行集成优化,构建随机需求下有退货的LIP模型。针对此问题求解的复杂性,设计了改进的自适应混合差分进化算法对模型进行整体求解。最后,通过多组算例验证了模型和算法的实用性和优越性,可为设施选址、库存控制和商品配送回收决策提供重要参考依据。     

面向电商终端物流配送的电动车配置与路径集成优化

在电子商务终端物流配送方面,存在能力与需求的矛盾。一方面,电动车存在货物容量约束和电池电量约束,配送能力有限;另一方面,一个物流配送点需要为众多的消费者进行门到门的配送,配送任务繁重。针对电子商务环境下终端物流配送规模大、电动车货物容量和行驶里程有限的问题,建立电商终端物流配送的电动车配置与路径规划集成优化模型,并提出一种基于临近城市列表的双策略蚁群算法,实现物流配送电动车辆配置与配送路径集成优化。该模型以电动车辆数最少和总路径最短为目标,以电动车货物容量和电池续航里程为约束,是带容量的车辆路径问题的进一步扩展,属于双容量约束路径规划问题。双策略蚁群算法在货物容量和续航里程的约束下,将蚁群搜索策略分为两类,即基于临近城市列表的局部搜索策略和全局搜索策略,在提高搜索效率的同时防止陷入局部优化。最后,通过阿里巴巴旗下菜鸟网络科技有限公司在上海的30组真实配送数据进行了测试,验证双策略蚁群算法显著优于一般蚁群算法。     

基于电子商务B2B平台的个性化定制产品供应链治理结构重复博弈分析

个性化定制产品的供应链上下游企业合作面临着双边道德风险问题,电子商务B2B平台提供了该问题的一种有效治理模式,但是也存在着平台企业索要商业贿赂等自身治理问题。本文构建了电子商务平台的个性化定制产品的供应链治理重复博弈模型,分析了定制化产品的供应链双边道德风险治理结构,以及平台自身的激励问题。研究结果表明,第一,通过电商平台的信息检索服务,可以有效规避双边道德风险问题,达成帕雷托最优的供应链上下游合作。第二,为了加强电子商务平台的自身治理问题,需要采取“按效果收费”制度,完善用户反馈信息记录,尤其是加强行业自律,提高电子商务平台的社会公信力和市场声誉。     

第三方电子商务平台与加盟商家联盟稳定性的演化博弈分析

针对电商平台的加盟商家的“跳单”现象,建立了第三方电子商务平台与加盟商家的博弈模型,利用演化博弈的方法分析了第三方电子商务平台的监管和加盟商家违约跳单的策略选择演化过程,给出了不同情形下他们的演化稳定均衡策略。若双方的策略不符合演化稳定均衡策略,则会影响他们形成的联盟的稳定性。此外,本文根据实际情况做了相应的参数设置和变量假设,并通过理论分析和情景仿真得到了加盟商家跳单的金额、平台因加强监管且加盟商家没有跳单而获得的额外收益等参数变化时对演化稳定均衡策略的影响。     

考虑平台优惠券的不同线上销售决策研究

本文以第三方电商平台是否发放优惠券和线上销售商是否进行集成销售(现售与预售并存)为标准构建四种Stackelberg模型,分析了平台佣金率、商品估值差异系数以及优惠券兑换率对供应链成员的决策与利润影响。结果表明,随着佣金率的提高,商品(现售和预售)的销售价及优惠券面值也随之增加;当预售成本足够低时,开展预售活动以及缩小估值差异可以提高线上销售商的收益;在一定条件下,提高优惠券兑换率可以增加供应链成员的收益,电商平台发放优惠券使其收益增加,却损害了销售商利润;相比其他销售方案,供应链系统利润在集成销售方案下最优。     

1995—2015年关中平原城市群生态系统服务价值（ESV）及其时空差异

为探究关中平原城市群土地利用程度对生态系统服务价值（ecosystem service value,ESV）的影响及变化情况,基于1995—2015年研究区5期土地利用数据,利用当量因子评估法、热点分析法和敏感性指数法对关中平原城市群ESV进行了评估,并分析了其时空规律。结果表明,20 a来,关中平原城市群ESV总体下降49.59亿元;在生态系统服务类型中,调节服务作用突出,其中水文调节占主导地位;ESV 冷点和热点分布具有明显的区域特征,主城区主要为ESV 冷点集群区,而秦巴山地、山西省东部林地及黄河、渭河等主要河流周边是ESV 热点集群区; 林地、水域和耕地对区域内ESV变化影响较大。获得的研究区ESV宏观变化规律,可为今后关中平原城市群生态环境保护、补偿和城镇发展规划的编制提供理论支撑。     

Validation of an Aesthetic Assessment System for Commercial Tasks

Automatic prediction of the aesthetic value of images has received increasing attention in recent years. This is due, on the one hand, to the potential impact that predicting the aesthetic value has on practical applications. Even so, it remains a difficult task given the subjectivity and complexity of the problem. An image aesthetics assessment system was developed in recent years by our research group. In this work, its potential to be applied in commercial tasks is tested. With this objective, a set of three portals and three real estate agencies in Spain were taken as case studies. Images of their websites were taken to build the experimental dataset and a validation method was developed to test their original order with another proposed one according to their aesthetic value. So, in this new order, the images that have the high aesthetic score by the AI system will occupy the first positions of the portal. Relevant results were obtained, with an average increase of 52.54% in the number of clicks on the ads, in the experiment with Real Estate portals. A statistical analysis prove that there is a significant difference in the number of clicks after selecting the images with the AI system.     

共生视角下我国区域创新生态系统发展观测——基于TOPSIS生态位评估投影模型的时空特征分析

为明确我国区域创新生态系统发展现状,以共生为视角,基于共生单元、共生基质、共生平台、共生网络、共生环境五大生态特征建立区域创新生态系统综合评价指标体系,以2007~2015年我国30个省市相关数据为样本,运用TOPSIS生态位评估投影集成模型及二次加权算法,对我国区域创新生态系统整体及各生态特征的发展状况进行静态和动态综合评价,并分析其时空特征、地区差异及关键因素变迁。结果表明:(1)我国区域创新生态系统发展整体呈趋好态势,东部地区发展趋缓且存在极化现象,中西部地区普遍抬升,地区间发展水平差距较大但随时间推移呈缩小趋势;(2)创新生态系统各生态特征均表现出“东高西低”的地区间非均衡现象,但其时空特征具有显著异质性;(3)区域创新生态系统长远发展的助力优先来自于共生平台和共生网络,而共生单元、共生基质和共生环境的重要性程度呈相对弱化态势。     

Competition of three species in an advective environment

Individuals in advective environments, for example rivers, coastlines, or the gut, are subject to movement with directional bias. We study how this movement bias shapes community composition by considering how the strength of movement bias affects the outcome of competition among three species. Our model is a system of three reaction-advection-diffusion equations with Danckwerts boundary conditions. Our key tool in this study is to use the dominant eigenvalue of the diffusion-advection operator in order to reduce the spatially explicit model to a spatially implicit ordinary differential equation model. After an in-depth analysis of the implicit model, we use numerical simulations of the explicit model to test the predictions obtained from the analysis. In general, we find a good qualitative agreement between the explicit and the implicit model. We find that varying the strength of advection can fundamentally alter the outcome of competition between the three species, and we characterize the possible transitions. In particular, water extraction and flow control can destabilize existing species communities or facilitate invasions of non-native species.     

Arsenic speciation in freshwater organisms from the river Danube in Hungary

Total arsenic and arsenic species were determined in a range of freshwater samples (sediment, water, algae, plants, sponge, mussels, frog and fish species), collected in June 2004 from the river Danube in Hungary. Total arsenic concentrations were measured by ICPMS and arsenic species were measured in aqueous extracts of the samples by ion-exchange HPLC-ICPMS. In order to separately determine the efficiency of the extraction method and the column recovery, total arsenic concentrations in the extracts were obtained in three ways: (i) ICPMS determination after acid digestion; (ii) flow injection analysis performed directly on the extract; (iii) the sum of arsenic species eluting from the HPLC column. Extraction efficiencies were low (range 10-64%, mean 36%), but column recovery was acceptable (generally >80%) except for the fish samples, where substantial, currently unexplained, losses were observed. The dominating arsenic species in the extracts of freshwater algae were arsenosugars, whereas arsenate [As(V)] was present only as a minor constituent. On the other hand, plant extracts contained only inorganic arsenic, except for two samples which contained trace amounts of dimethylarsinate (DMA) and the tetramethylarsonium cation (TETRA). The oxo-arsenosugar-phosphate (ca. 35% of extractable arsenic) and the oxo-arsenosugar-glycerol (ca. 20%) as well as their thio-analogues (1-10%) were found in the mussel extracts, while arsenobetaine (AB) was present as a minor species only. In general, fish extracts contained only traces of arsenobetaine, and the oxo-arsenosugar-phosphate was the major arsenic compound. In addition, samples of white bream contained thio-arsenosugar-phosphate; this is the first report of a thio-arsenical in a fish sample. The frog presented an interesting arsenic speciation pattern because in addition to the major species, arsenite [As(III)] (30%) and the tetramethylarsonium cation (35%), all three intermediate methylation products, methylarsonate (MA), dimethylarsinate and trimethylarsine oxide (TMAO), and arsenate were also present. Collectively, the data indicate that arsenobetaine, the major arsenical in marine animals, is virtually absent in the freshwater animals investigated, and this represents the major difference in arsenic speciation between the two groups of organisms.