基于MDDP系统的智能压机线开发

冲压压力机作为汽车制造行业表面件加工的设备,具有多工况,变载荷、重载荷的特点,在零件加工过程中需要持续往复运行.随着设备的负荷不断增大使用年限地不断增长,一些大型的机械故障也因为磨损、疲劳以及维护保养不及时彻底等因素而开始出现,且出现频次逐渐增高.在既有的正常点巡检和例行检修保养的前提下,一些故障和问题仍无法及时发现或...     

基于p-中位模型的单目标物流配送时间点决策

为了确定最佳的配送时间点, 利用p-中位模型, 研究单配送目标物流配送的时间点决策问题, 建立了最少配送次数、最短配送时间和运费有折扣情况下最低运输成本的数学模型, 并以航空货物配送为例, 利用ILOG优化软件分别计算了3种模型的配送时间点。计算结果表明: 实现最少配送次数需要的平均配送时间是最短平均配送时间的1.6倍, 在运费有折扣情况下实现最低运输成本所需配送时间比没有折扣情况下的略长; 货主或者物流服务商可以根据客户要求选择相应的模型, 确定配送时间点, 实现最优决策。     

Intra-household bargaining for school trip accompaniment of children: A group decision approach

This paper tests a group decision-making model to examine the school travel behavior of students 6–18 years old in the Minneapolis-St. Paul Metropolitan area. The school trip information of 1737 two-parent families with a student is extracted from Travel Behavior Inventory data collected by the Metropolitan Council between the Fall 2010 and Spring 2012. The model has four distinct characteristics including: (1) considering the student explicitly in the model, (2) allowing for bargaining or negotiation within households, (3) quantifying the intra-household interaction among family members, and (4) determining the decision weight function for household members. This framework also covers a household with three members, namely, a father, a mother, and a student, and unlike other studies it is not limited to dual-worker families. To test the hypotheses we build two models, each with and without the group-decision approach. The models are separately built for different age groups, namely students 6–12 and 12–18 years old. This study considers a wide range of variables such as work status of parents, age and gender of students, mode of travel, and distance to school. The findings of this study demonstrate that the elasticities of the two modeling approaches differ not only in the value, but in the sign in some cases. In 63% of the cases the unitary household model underestimates the results. More precisely, the elasticities of the unitary household model are as much as 2 times more than that of the group-decision model in 20% of cases. This is a direct consequence of model misspecification that misleads both long- and short-term policies where the intra-household bargaining and interaction is overlooked in travel behavior models.     

Adapting the shipping sector to stricter emissions regulations: Fuel switching or installing a scrubber?

This paper examines how the existing fleet in the shipping industry can be adapted to the new emission regulations through the two main techniques that currently exist: (a) the use of low-sulphur marine diesels; and (b) the installation of scrubbers. A method is presented here for drawing up an economic assessment of both these techniques under uncertainty. It enables the best option to be selected at any given time taking into account fuel prices (spot and futures), scrubber installation costs, the time that the vessel operates in an Emission Control Area (ECA) and the remaining useful lifetime of the vessel. The paper also considers the possibility of an unexpected change from a non-ECA navigation area to an ECA. The assessment is carried out in a manner consistent with marine diesel and crude oil spot and futures market quotes. Our results show the net present value of investing in the installation of scrubbers and investing in changing fuel types for different assumptions on how vessels are operated. We also analyse increases in fuel consumption and CO₂ emissions as a consequence of using scrubbers and how they affects the financial analysis if such incremental emissions must be paid under a CO₂ pricing mechanism.     

A threshold model of social contagion process for evacuation decision making

Individual evacuation decisions are often characterized by the influence of one’s social network. In this paper a threshold model of social contagion, originally proposed in the network science literature, is presented to characterize this social influence in the evacuation decision making process. Initiated by a single agent, the condition of a cascade when a portion of the population decides to evacuate has been derived from the model. Simulation models are also developed to investigate the effects of community mixing patterns and the initial seed on cascade propagation and the effect of previous time-steps considered by the agents and the strength of ties on average cascade size. Insights related to social influence include the significant role of mixing patterns among communities in the network and the role of the initial seed on cascade propagation. Specifically, faster propagation of warning is observed in community networks with greater inter-community connections.     

基于模糊多属性决策方法的承发包模式比较研究

在前人对工程承发包模式研究成果的基础上,从项目成本、效益以及风险的角度建立了比较指标体系,并提出了指标赋值方法。将承发包模式的选择问题归结为多属性决策中（MADM）的排序问题,采用离差最大化准则下的多属性决策的最优组合赋权方法来对各指标的权重进行赋值,并采用TOPSIS方法来对各方案进行比较研究。,最后通过算例进行计算和分析。     

基于分类决策树的城市内部迁居人群通勤时间预测模型

针对迁居个体长距离、长时间的通勤现象,以南京迁居人群通勤出行多源数据为基础,综合考虑迁居人群个人家庭属性、迁居属性、建成环境属性及通勤属性,建立迁居人群通勤时间多元线性回归模型,分析各属性对通勤时间的影响. 结合多元线性回归和Logistic 回归确定决策树模型入选变量和通勤时间离散值,利用C4.5 算法建立迁居人群通勤时间决策树,以决策树结构揭示不同背景下迁居个体通勤时间模式特征. 结果显示,相较于个人家庭属性,职住同区、通勤出发时刻、住房类型、通勤距离、通勤方式及社区至主干道的便捷程度对迁居个体通勤时长的影响更为显著,侧面反映社区微观建成环境优化政策更利于提升迁居个体通勤效率.     

人工神经网络在变量选择中的应用

笔者针对综合评价建模过程中变量选取方法的局限性 ,应用神经网络原理对输出值各影响因素进行贡献分析 ,进而剔除影响不显著或不重要的因素 ,为模型建立、综合评价和决策过程中选取合适指标提供了可靠依据     

基于数据仓库的城轨客运营销决策支持系统

对建立城市轨道交通客运营销信息数据仓库系统的关键技术进行研究和探讨,提出客运营销数据仓库系统建设的必要性,分析系统数据仓库的主要特征、数据组织特点、决策数据对象及相关主题,采用信息包图技术对数据仓库进行设计.     

基于资本投资决策理论的工程方案决策与比选方法

研究目的：在基础工程项目建设的准备阶段，较为准确地预测工程方案的工程费用，选择出对不同主体（投资公司和社会）均较经济、合理的方案；真实地反应项目所消耗的“土地资源资产”的价值，为防止国有资产的流失提供合理依据。 研究方法：引入投资决策理论和机会成本分析理论，采用动态的工程费用计算方法，考虑工程方案整个比选期限内的全部费用。 研究结论：由于费用计算存在失真，所以同一个方案对于不同的主体而言，其经济性的评价结果是不一致的；引入投资决策理论，可以较为准确地预测工程方案的工程费用现值；利用机会成本分析理论，可以真实地反应项目所消耗的“土地资源资产”的价值；必须考虑工程方案整个比选期限内的全部费用，并采用动态的费用计算方法，才能较为全面、真实地反映工程的实际造价。