Optimization of a feeder-bus route design by using a multiobjective programming approach

This paper presents a feeder-bus route design model, capable of minimizing route length, minimizing maximum route travel time of planned routes, and maximizing service coverage for trip generation. The proposed model considers constraints of route connectivity, subtour prevention, travel time upper bound of a route, relationships between route layout and service coverage, and value ranges of decision variables. Parameter uncertainties are dealt with using fuzzy numbers, and the model is developed as a multiobjective programming problem. A case study of a metro station in Taichung City, Taiwan is then conducted. Next, the programming problem in the case study is solved, based on the technique for order preference by similarity to ideal solution approach to obtain the compromise route design. Results of the case study confirm that the routes of the proposed model perform better than existing routes in terms of network length and service coverage. Additionally, increasing the number of feeder-bus routes decreases maximum route travel time, increases service coverage, and increases network length. To our knowledge, the proposed model is the first bus route design model in the literature to consider simultaneously various stakeholder needs and support for bus route planners in developing alternatives for further evaluation efficiently and systematically.     

覆盖层次结构的知识距离刻画方法

为了研究覆盖上的层次结构问题,在覆盖上提出了知识距离的概念,并由覆盖知识距离构建了两种不同的代数格,最终使用由这两种代数格所诱导出的偏序关系来刻画不同覆盖之间的关系.实例分析表明由知识距离格方法来研究覆盖的层次问题是切实可行的.由此可以看出,知识距离为研究覆盖的层次问题提供了一种新的有效方法.     

Approximation algorithms for the bid construction problem in combinatorial auctions for the procurement of freight transportation contracts

Trucking companies (carriers) are increasingly facing combinatorial auctions conducted by shippers seeking contracts for their transportation needs. The bid valuation and construction problem for carriers facing these combinatorial auctions is very difficult and involves the computation of a number of NP-hard sub problems. In this paper we examine computationally tractable approximation methods for estimating these values and constructing bids. The benefit of our approximation method is that it provides a way for carriers to discover their true costs and construct optimal or near optimal bids by solving a single NP-hard problem. This represents a significant improvement in computational efficiency. We examine our method both analytically and empirically using a simulation based analysis.     

长寿型路面设计探讨

对于黑色路面车流量大、损坏比较严重的路段,采用黑色原路面加罩白色路面结构层方法实际运用效果比较理想,能使道路寿命大大延长。该文主要介绍了长寿型路面的设计与应用实践。     

ERG树脂碎石薄层罩面的应用性能

采用室内试验和对比分析方法,从黏结性、变形协调性、施工和易性、抗滑性、耐磨耗性等方面研究了ERG树脂碎石薄层罩面在大跨径钢桥面环氧沥青铺装预防性养护应用中的材料性能.研究结果显示,ERG树脂碎石薄层罩面具有固化时间短、强度和变形能力较高、与环氧沥青铺装粘结良好、耐久性较好等特点,能够满足钢桥面环氧沥青铺装预防性养护的技术要求.     

基于集合覆盖模型的装备故障诊断方法研究

随着武器装备的不断发展,其结构与组成越来越复杂,机内测试虽然能给出报警,但大多依靠人工经验判断是否为故障,缺乏故障推理机制,一般不能隔离故障。论文以故障测试相关性矩阵为基础,将故障诊断过程归纳为经典的集合覆盖问题,通过快速求解该数学问题,给出故障诊断结果,单故障和双故障实例证明该方法合理有效。     

高速公路沥青面层用集料加工工艺研究

针对目前中国高速公路建设中,沥青路面施工存在的问题,从沥青面层用集料加工工艺方面入手,给出了适合于高速公路沥青面层用粗、细集料的加工工艺,不仅可以规范集料的加工工艺、提高沥青路面的施工质量,也可为编制相关的技术标准起到一定的参考作用.     

电动物流车蓄电池支架优化设计

创建组合工况,采用加速度加载的仿真方法,基于变密度法和“包裹面”方案对电动物流车蓄电池支架进行结构拓扑优化,并通过尺寸优化对支架进行轻量化设计,得到符合性能和轻量化要求的结构设计方案。仿真结果表明,优化后的蓄电池支架整体刚度提高了10.5%,总质量降低了29.2%.     

基于上落客时空特征的出租车停靠站选址模型

为了规范出租车运营,改善出行者候车环境,提高出租车经营效益,进行基于出租车出行需求特征的停靠站选址研究有着十分重要的现实意义.本文首先界定了出租车出行需求时空热点的含义,基于样本出租车GPS数据研究出行需求的时空聚集特征,得到了出行高峰时段和出行热点区域.将出行需求作为依据应用于出租车停靠站选址,提出了基于最大覆盖的停靠站选址模型,同时结合出行者的不确定性交通行为和消费特点,在车站服务能力、出行者步行距离和计划修建数量等方面分析了模型的适用条件.实例区域的选址研究结果表明,以客观需求为依据的选址方法,可以更好地契合出行者的出行需求,具有较高的实用性.     

牺牲阳极和包覆材料联合保护在友谊港的防腐应用

根据不同海洋腐蚀区域的特点,采取涂层保护、冷包缠防腐保护和牺牲阳极阴极保护组合保护的形式,对毛里塔尼亚友谊港钢管桩进行防腐修复。施工过程中严格质量控制,达到了预期的实施效果,顺利通过了友谊港业主的验收。