Scheduling of Intelligent and Autonomous Vehicles under pairing/unpairing collaboration strategy in container terminals

A new class of Intelligent and Autonomous Vehicles (IAVs) has been designed in the framework of Intelligent Transportation for Dynamic Environment (InTraDE) project funded by European Union. This type of vehicles is technologically superior to the existing Automated Guided Vehicles (AGVs), in many respects. They offer more flexibility and intelligence in maneuvering within confined spaces where the logistic operations take place. This includes the ability of pairing/unpairing enabling a pair of 1-TEU (20-foot Equivalent Unit) IAVs dynamically to join, transport containers of any size between 1-TEU and 1-FFE (40-foot Equivalent) and disjoin again. Deploying IAVs helps port operators to remain efficient in coping with the ever increasing volume of container traffic at ports and eliminate the need for deploying more 40-ft transporters in the very confined area of ports. In order to accommodate this new feature of IAVs, we review and extend one of the existing mixed integer programming models of AGV scheduling in order to minimize the makespan of operations for transporting a set of containers of different sizes between quay cranes and yard cranes. In particular, we study the case of Dublin Ferryport Terminal. In order to deal with the complexity of the scheduling model, we develop a Lagrangian relaxation-based decomposition approach equipped with a variable fixing procedure and a primal heuristics to obtain high-quality solution of instances of the problem.     

城市轨道交通高峰线路客流协同控制方法

在线路客流控制中，需同时考虑各个车站控流方案的可执行性与协同性. 采用 Fisher 最优分割法确定合理客流控制时段，基于此建立以乘客总等待时间最少和旅客周转量最大为目标的线路客流协同控制线性规划模型. 基于成都地铁2 号线AFC数据进行实验，针对协同控流与非协同控流方案，以及不同客流控制时段划分方案下的协同控流方案进行对比实验. 算例中：协同控流方案在旅客周转量下降约1.0%的情况下，乘客总等待时间减少约 56.7%；基于Fisher 最优分割法确定的时段划分方案中协同控流方案在乘客总等待时间方面最优，并具有很好的可执行性.     

灾后恢复阶段多期道路交通网络重建规划

灾后路网重建规划可分为应急阶段和全面恢复阶段。文中建立了灾后恢复阶段多期路网重建规划的双层模型，并采用灵敏度分析方法进行求解。上层模型考虑到建设资源的限制，以工程总效益最大为目标建立多期工程效益模型；下层模型是基于出行时间可靠性的用户均衡分配模型。最后结合实际路网进行了算例分析，证明模型和算法是有效的。     

有限元分析中三维体元和梁元的非节点连接

在对三维体元任一点移动和转动分析的基础上,导出了体元和梁元恰当连接应满足的多点约束方程,通过直接代入梁元的单元分析进行自由度替换实现了体梁的良好连接.本文方法对体元和梁元的连接形式具有较强的适应能力,应用方便,算例表明具有较高的数值精度.     

An Intelligent Response Surface Methodology for Modeling of Domain Level Constraints

An effective modeling method of domain level constraints in the constraint network for concurrent engineering （CE） was developed. The domain level constraints were analyzed and the framework of modeling of domain level constraints based on simulation and approximate technology was given. An intelligent response surface methodology （IRSM） was proposed, in which artificial intelligence technologies are introduced into the optimization process. The design of crank and connecting rod in the V6 engine as example was given to show the validity of the modeling method.     

一类运输工具带双重能力约束的LRP问题

分析了一类运输工具受双重能力约束的LRP问题，即在物流网络节点最大单批处理能力及运输工具总运输能力双重约束的情况下,如何进行物流中心选址和运输路线安排，使总的费用最小,模型假设网络系统满足如下条件：①节点的最大单批处理能力是逐层变化的，②货物只能用不同运输工具经过某一物流中心进行中转运输．文中建立了混合整数规划模型，提出了一种优化算法，并用优化算法对实例进行求解．     

高速动车组合理下线范围的决策模型及算法研究

随着我国铁路客运向高速化的全面迈进,高速铁路建设和运营的技术条件已经有了较大进步,因而高速动车组驶离高速线到既有线运行的模式逐渐成为运输组织模式研究的焦点,而高速动车组合理下线范围则是其中的关键问题之一。以此为背景,在分析多种铁路运输产品存在时旅客选择行为的基础上,将用户平衡理论应用于不同铁路运输产品间的客流分配问题中,同时考虑旅客和铁路客运部门两方面的利益,构造了一个双层规划模型来描述有多种铁路运输产品存在、且总客运需求变动情况下高速动车组的合理下线范围问题,并提出了基于灵敏度分析的求解算法。最后通过算例,分析在不同运价率条件下高速动车组合理下线范围的变化规律。     

The effect of plastic constraint on the initiation of ductile tears in shipbuilding structural steels

In this paper, the effect of plastic constraint on the initiation of ductile tears in four different shipbuilding structural steels has been experimentally studied by measuring the J-integral and crack opening displacement COD at initiation in three-point bend specimens with deep and shallow notches. Experimental results of seven groups of different strength alloy steels show that both Si and Ji values of ductile tear from the shallow crack specimens which have less constraint flow field are significantly higher than those of deeply notched specimens. Slip-line-field analysis shows that, for shallow crack, the hydrostatic stress is lower than that from standard deeply cracked bend specimen, which develops a high level of crack tip constraint, provides a lower bound estimate of toughness, and will ensure an unduly conservative approach when applied to structural defects, especially if initiation values of COD and J-integral are used.     

AutoLISP程序设计的若干问题

本文剖析了 AutoLISP 程序的结构特点,运行长大程序的措施和数据文件的组织等三个方面的问题.     

周期运行图编制模型与算法研究

在周期运行的运输组织模式下,所有列车在车站到发都是周期循环发生的。将安排列车运行线的问题看作周期事件安排问题,并借助周期约束图及周期势差模型,可以建立周期运行图网络模型。模型充分考虑到列车不同情况下的停站时间、到发安全间隔等各项周期约束,并将列车的总停留时间最小作为目标函数。当约束图顶点和弧的数量众多时,模型的求解将比较困难。通过选择合适的约束图生成树,找到变量的合理取值范围,并对模型进行一些预先简化处理,可以降低模型的求解难度。最后求解一个区段不同列车开行方案的周期运行图,验证模型的可行性。