全渠道零售场景下配送车辆路径问题     

施天娇  杨斌  朱小林 《上海海事大学学报》2020,41(2):51-57

为研究全渠道零售的配送系统对企业物流成本的影响,综合考虑时间窗、车型选择等因素,以运输成本最低为目标,建立高度协同的全渠道零售场景下的物流配送模型。该模型采用自适应遗传算法求解,利用MATLAB进行算例分析。结果显示:全渠道零售模式下的车辆调度方案能迅速响应消费者需求,与一般配送模式相比可以减少物流成本,优化车辆配置。与粒子群优化算法相比,自适应遗传算法的运行时间更短、优化结果更好,这验证了模型和算法的可行性和有效性。  相似文献   

基于TOPSIS改进Shapley值的邮轮公司与航空公司合作收益分配     

闵德权  赵琼  崔琪  刘茹 《上海海事大学学报》2020,41(3):73-81

为制定"邮轮+飞机"合作销售模式下邮轮公司与航空公司合理的收益分配方案,保持合作的稳定性和积极性,构建合作收益模型,求解最优合作收益。考虑风险和资源投入因素,构建基于改进Shapley值的收益分配模型,对最优合作收益进行公平、合理的分配;基于TOPSIS对收益分配方案进行综合优化,以此提供有效的解决方案。算例结果表明:优化后的方案考虑合作成员多方面的贡献,对投入较多的公司进行一定的补偿,具有可行性和公平性。  相似文献   

离岸集装箱码头新装卸工艺模式下陆域集疏运堆场堆存空间分配     

杨晓斌  余思勤  沈一帆 《上海海事大学学报》2020,41(4):8-14

离岸集装箱码头因其岛屿面积限制，难以通过扩建码头内部堆场增加吞吐能力。为解决这个问题，提出一种离岸集装箱码头新装卸工艺模式。新装卸工艺模式是通过在离岸集装箱码头附近的陆域地带建设陆域集疏运堆场,与离岸集装箱码头进行协同装卸作业的模式。陆域集疏运堆场堆存空间分配的目标是满足离岸集装箱码头装卸作业预翻倒要求;单批次输送集装箱的量受到陆岛运输最大通行能力限制。根据上述目标与特点，构建新装卸工艺模式下陆域集疏运堆场堆存空间分配模型，并设计蒙特卡洛树搜索算法进行求解。通过算例分析验证模型的有效性。结果表明该方法能够满足陆域集疏运堆场堆存空间分配需求并提高离岸集装箱码头的吞吐能力。  相似文献   

我国大学生高水平排球队空间分布特征及影响因素研究*     

马茂森    李毅钧  张〓兵  杨玲 《广州体育学院学报》2020,(5):78-84

利用核密度分析、巴雷托截取法和多元回归分析等方法，对我国大学生高水平排球队空间分布特征和影响因素进行分析。主要结论有：大学生高水平排球队的数量呈波动上升趋势；在规模结构上，大学生高水平排球队数量规模的省际分布呈现倒“金字塔”结构，而配比规模的省际分布呈现“金字塔”结构，且极不平衡；在空间格局上，具有显著的区域差异，表现出东部区域较多；在集聚特征上，大学生高水平排球队主要分布在直辖市和省会城市，主要集聚在京津翼地区和长江流域，其他地区比较分散；在空间竞技实力上，具有显著的区域不平衡性，呈现“南弱北强”的特征；影响大学生高水平排球队空间分布的主要因素有高校招生条件、本科院校数量、经济发展实力和体育发展水平。  相似文献   

Is Journalism Going Global? Finding Answers in Quantitative Studies Employing the Concepts of the “Culture Peg” and the “Culture Link”*     

Miki Tanikawa 《Journalism Practice》2019,13(8):922-926

  相似文献   

基于新鲜度和配送成本的易腐食品配送路径   总被引：1，自引：0，他引：1  

李畅  陈淮莉 《上海海事大学学报》2019,40(1):14-20

为解决企业在制定易腐食品配送计划时难以权衡配送总成本与交付产品的新鲜度的问题,建立以配送总成本最低和交付产品平均新鲜度最大为目标,带时间窗的易腐食品配送路径规划模型。采用自适应差分进化(differential evolution,DE)算法求解模型,通过数值算例验证模型和算法的有效性。与基本DE算法和基本蚁群算法的求解结果进行对比,自适应DE算法的求解结果更优,收敛速度更快。求得的帕累托解集表明配送总成本与交付产品平均新鲜度相悖,增加少量的配送成本可以使交付产品的平均新鲜度得到大幅提升。对易腐食品保质期、时间窗宽度和车辆装载量进行灵敏度分析,为企业在不同配送情景下在配送总成本与交付产品的平均新鲜度之间的权衡提供参考。  相似文献   

Responses to oral glucose challenge differ by physical activity volume and intensity: A pilot study     

Trevor N. Simper  Cecile Morris  Anthony Lynn  Ciara O'Hagan  Karen Kilner 《运动与健康科学(英文)》2020,9(6):645-650

BackgroundOne-hour postprandial hyperglycemia is associated with increased risk of type 2 diabetes and cardiovascular disease. Physical activity (PA) has short-term beneficial effects on post-meal glucose response. This study compared the oral glucose tolerance test results of 3 groups of people with habitually different levels of PA.MethodsThirty-one adults without diabetes (age 25.9 ± 6.6 years; body mass index 23.8 ± 3.8 kg/m²; mean ± SD) were recruited and divided into 3 groups based on self-reported PA volume and intensity: low activity < 30 min/day of moderate-intensity activity (n = 11), moderately active ≥ 30 min/day of moderate-intensity PA (n = 10), and very active ≥ 60 min/day of PA at high intensity (n = 10). Participants completed an oral glucose tolerance test (50 g glucose) with capillary blood samples obtained at baseline, 15 min, 30 min, 45 min, 60 min, 90 min, and 120 min post-ingestion.ResultsThere were no significant differences between groups for age or body fat percentage or glycated hemoglobin (p > 0.05). The groups were significantly different in terms of baseline glucose level (p = 0.003) and, marginally, for gender (p = 0.053) and BMI (p = 0.050). There was a statistically significant effect of PA on the 1-h postprandial glucose results (p = 0.029), with differences between very active and low activity groups (p = 0.008) but not between the moderately active and low activity groups (p = 0.360), even when baseline glucose level and gender differences were accounted for. For incremental area under the curve there was no significant effect of activity group once gender and body fat percentage had been accounted for (p = 0.401). Those in the low activity group took 15 min longer to reach peak glucose level than those in the very active group (p = 0.012).ConclusionThe results suggest that high levels of PA have a beneficial effect on postprandial blood glucose profiles when compared to low and moderate levels of activity.  相似文献   

College course scarcity and time to degree     

《Economics of Education Review》2014

College students are taking longer to earn baccalaureate degrees now than ever before, but little is known about institutional factors that may contribute to this trend. In this paper we investigate an important institutional constraint—course scarcity—that we hypothesize may be associated with increased time to degree. We employ a unique administrative dataset from a large, moderately selective, public institution and use an instrumental variables approach, identifying off the random registration times assigned to students. Results suggest that course scarcity does not delay students’ graduation. We explore alternative explanations for our findings and discuss a variety of other factors correlated with time to baccalaureate completion.  相似文献   

Distribution and denomination in Papua New Guinea: a field method and its results     

Anthony J. Pickles 《Journal of Cultural Economy》2020,13(2):185-206

ABSTRACT

In highland Papua New Guinea wealth distribution after a windfall is typically concealed by the donor. This trend was made easier by the introduction of state-issued currency, such that wealth reckoning and especially distribution preferences are often shrouded in mystery. The researcher set out to learn how denomination structures those money transfers by employing a semi-structured interview method centered around hypothetical distributions based on everyday encounters. Across four tailored ‘scenarios,’ fifteen Papua New Guinean participants dwelt on who to give money to, why, and under what conditions. Observations are made about the driving forces in distribution practices, the pecuniary conception of certain relationships’ importance, and relationships that turn on local conceptions of how to capitalize on the way money operates, thus demonstrating the utility of a culturally sensitive quantitative methodology.  相似文献   

基于文献计量的我国区块链研究的知识网络与结构分析     

汪园  王学东  李金鑫 《现代情报》2018,38(1):147-153

区块链是分布式数据存储、点对点传输、共识机制、加密算法等计算机技术在互联网时代的创新应用模式。目前已经引起国内外各界的广泛关注，成为技术创新的热点名词。本文基于客观数据分析了区块链研究的发展态势和阶段、学科分布和结构、研究热点和趋势等，旨在为我国后续的区块链研究和发展提供参考。本文以CNKI中国学术期刊网络出版总库的相关研究论文为依据，运用文献计量方法以及Citespace等可视化软件对区块链研究现状的知识网络和理论结构进行了分析。分析结果表明：区块链研究发文量从2015年开始呈现出突发式的井喷状态，结合当前政策环境显示，目前区块链的发展还处于探索和研究阶段，因此研究论文中科普评论类文献比重较大；从研究的知识网络与结构来看，区块链研究形成了计算机科学、工程学以及电信科学、自动化技术为依托的技术学科群和以金融、能源与动力工程、工业制造、供应链、文化教育、医药卫生等众多应用学科群；这些学科结构要素共同形成了区块链研究中技术基础、技术应用以及社会宏观效应三大层面的研究热点。  相似文献