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汪国权 《铁路工程造价管理》2012,27(4):1-3
无砟轨道具有高平顺性、高稳定性、高可靠性、维修量少等优点,在高速铁路工程建设中得到推广应用。我国在引进无砟轨道技术消化、吸收的基础上,通过技术创新研制开发出具有自主知识产权的CRTSⅢ型板式无砟轨道结构,并成功应用于工程建设。为保证工程建设的开展,首先应建设CRTSⅢ型轨道板预制场,此文就CRTSⅢ型轨道板预制场设置原则、建设规模及标准进行论述,并对其投资进行分析,可为今后工程的建场提供借鉴。 相似文献
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In this paper, we present a case study on planning the locations of public electric vehicle (EV) charging stations in Beijing, China. Our objectives are to incorporate the local constraints of supply and demand on public EV charging stations into facility location models and to compare the optimal locations from three different location models. On the supply side, we analyse the institutional and spatial constraints in public charging infrastructure construction to select the potential sites. On the demand side, interviews with stakeholders are conducted and the ranking-type Delphi method is used when estimating the EV demand with aggregate data from municipal statistical yearbooks and the national census. With the estimated EV demand, we compare three classic facility location models – the set covering model, the maximal covering location model, and the p-median model – and we aim to provide policy-makers with a comprehensive analysis to better understand the effectiveness of these traditional models for locating EV charging facilities. Our results show that the p-median solutions are more effective than the other two models in the sense that the charging stations are closer to the communities with higher EV demand, and, therefore, the majority of EV users have more convenient access to the charging facilities. From the experiments of comparing only the p-median and the maximal covering location models, our results suggest that (1) the p-median model outperforms the maximal covering location model in terms of satisfying the other’s objective, and (2) when the number of charging stations to be built is large, or when minor change is required, the solutions to both models are more stable as p increases. 相似文献
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基于轴系扭振计算分析,对某型船用大功率柴油发电机组轴系加装惯量盘,使其扭转振动固有频率低谐次避开工作转速区,消减机组运行安全隐患,并借助三维造型和有限元分析优化惯量盘结构设计。 相似文献
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���ڴֲڼ����г����е��������о� 总被引:1,自引:0,他引:1
粗糙集是一种处理不完备、不精确数据的新方法,其数据处理过程与行车调度员进行列车运行调整的决策过程非常相似,都是从已有的大量经验数据中提取出决策规则并用于指导新的决策判断.通过对行调人员运行调整和决策的详细剖析,构建了列车运行调整的粗糙集模型,提出了基于粗糙集的列车运行调整系统知识的获取与表达的方法,改进了运行调整的粗糙集决策规则的约简算法,思路更清晰,步骤更完善;最后通过对DMIS系统中部分列车运行数据的挖掘,证明了算法的实用性,从提取出的规则能直观地判断出各条件属性对决策的影响程度,为行调做出新的决策提供了有价值的参考;形成了完整的粗糙集列车运行调整体系. 相似文献
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一种高效的简化可辨识矩阵集成算法 总被引:1,自引:0,他引:1
基于可辨识矩阵的约简算法,需要生成许多无用的元素,因而算法效率不高.针对这一问题,基于动态思想,设计了一个新的集成算法,新算法在生成可辨识矩阵的过程中不用生成大量的无用元素,减少了存储量和计算量,从而使算法的效率得到提高.最后给出了一个实例说明新算法的高效性. 相似文献
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This paper introduces a bidirectional multi-shift full truckload transportation problem with operation dependent service times. The problem is different from the previous container transport problems and the existing approaches for container transport problems and vehicle routing pickup and delivery are either not suitable or inefficient. In this paper, a set covering model is developed for the problem based on a novel route representation and a container-flow mapping. It was demonstrated that the model can be applied to solve real-life, medium sized instances of the container transport problem at a large international port. A lower bound of the problem is also obtained by relaxing the time window constraints to the nearest shifts and transforming the problem into a service network design problem. Implications and managerial insights of the results by the lower bound results are also provided. 相似文献