对铁路客站概算编制几个问题的探讨

铁路站房一般具有跨度大、空间大、荷载重等特点,他不同于一般的工业与民用建筑,在编制概预算时如果直接套用地方定额,会存在一定的不合理性.此文从站房基坑土方开挖、大体积混凝土支撑系统、大型钢结构安装工程、建筑装修支撑体系等方面,分析对编制项目概算的影响.通过分析与对比,提出采用地方定额的建议,以供在今后编制站房概算中借鉴.     

城市轨道交通系统可靠性指标及其计算

基于系统可靠性概念,构建了城市轨道交通系统的可靠性指标体系,提出了运营可靠度、运营恢复度及运营利用率等指标的定义,给出了相应的计算方法。应用该方法计算了上海轨道交通1、2、3号线的可靠性指标。     

Elasticities for taxicab fares and service availability

This study utilizes a unique dataset from New York City to examine the effects of taxi fare increases on trip demand and the availability of taxi service. The elasticity of trip demand with respect to fares is estimated to be –0.22; the elasticity of service availability with respect to the taxi fare is 0.28; and the elasticity of service availability with respect to total supply of service is near 1.0. These results have important implications for taxi regulatory decisions. First, fare increases do substantially increase industry revenues but at a lesser rate than the percentage increase in the fare. The implication for policy-makers is that fare elasticities must be carefully considered to obtain desired improvements in drivers' earnings. Second, service availability -- an important aspect of service quality that is generally overlooked during fare policy debates -- should be a central consideration in fare setting, given the considerable impact of fares on availability. Finally, where the supply of cabs needs to be expanded, the number of cabs can be significantly increased without harming the revenue stream of existing operators. This finding alleviates a major industry objection to issuing additional taxicab licenses.     

并网型风电机组可靠性设计

介绍了并网型风电机组可靠性指标及其评估方法,及并网型风电机组的运行情况;根据并网型风电机组可靠性串联模型,对并网型风电机组进行可靠性设计,找出其薄弱环节,提高其可靠性,达到提高可利用率和年发电量的目的。     

A multiobjective model for maximizing fleet availability under the presence of flight and maintenance requirements

Every aircraft, military or civilian, must be grounded for maintenance after it has completed a certain number of flight hours since its last maintenance check. In this paper, we address the problem of deciding which available aircraft should fly and for how long, and which grounded aircraft should perform maintenance operations, in a group of aircraft that comprise a combat unit. The objective is to achieve maximum availability of the unit over the planning horizon. We develop a multiobjective optimization model for this problem, and we illustrate its application and solution on a real life instance drawn from the Hellenic Air Force. We also propose two heuristic approaches for solving large scale instances of the problem. We conclude with a discussion that gives insight into the behavior of the model and of the heuristics, based on the analysis of the results obtained.     

高速公路养护费用收支测算模型的研究与建立

针对国内高速公路养护费用测算现状和存在的问题,建立养护费用收支测算模型,通过综合各种影响因素计算出其加权系数,进而得出收支比,最后结合实例,使该模型的实用性得到验证。     

小波变换在轨道静态功率谱密度获取中的应用

利用小波变换将轨道不平顺信号和所得谱图信号分解到互不重叠的频带上,结合小波阈值处理技术,对小波高频系数进行阈值量化处理,滤掉其中某些频段内的干扰与噪声信号,然后对信号进行重构,从而实现了对信号的去噪和对谱图信号的平滑处理。结果表明,该方法成功地获取了轨道静态功率谱密度,有效提高了轨道静态参数信噪比和轨道静态功率谱密度图的可视性。     

高等级公路填石路堤压实费用补充定额的编制

中华人民共和国行业标准《公路路基施工技术规范》(JTJ033-95)对填石路堤的压实提出了明确要求,但现行《公路工程概预算定额》中却没有高速公路及一级公路填石路堤的压实定额。因此。只有通过现场试验路和工程实践编制补充定额,才能较合理准确地计列该费用。     

浅谈配置高性能混凝土的主要技术途径

结合工程实践,根据高性能混凝土高强度要求,对配制高性能混凝土的技术及施工工艺进行了论述。     

铁路勘测设计一体化的应用实践

铁路勘测设计一体化系统是综合性应用研究项目,在具体实施过程中应以科技开发为先导,生产使用为目标,研究成果在生产中不断进行试验,才能逐步得到完善。本文就铁道部第一勘测设计院先后在西安南京线初测初步设计、包西线神延段部分段落实定测技术设计、西安南京线定测技术设计三个建设项目上进行勘测设计一体化试点工作的情况进行了认真客观的总结。实践证明：首先,勘测设计一体化是可行的,是勘测设计领域实现科技进步的必经之