对招投标活动中行政监督问题的探讨

结合我国工程建设项目招投标工作的现状,就如何进一步完善和加强行政监督工作力度的问题,提出了自己的一些见解,与从事行政监督工作的人员共同探讨,也可供有关行政管理部门参考。     

大型铁路工程BIM设计的探索及实现

BIM技术的应用能够提升铁路工程建设技术水平及信息管理能力,也是铁路工程建设信息化的核心和方向。BIM信息模型是BIM技术应用的基础文件,设计单位在BIM技术的应用中起牵头及主导作用。在现阶段,铁路工程BIM设计多停留在单体设计的水平上,BIM技术在铁路工程中的探索及应用也停留在较为初级的阶段;针对此情况,我院在迁建西安客车段、机务段这一大型铁路工程设计过程中进行了积极探索,采用BIM技术对两段进行了全专业、全内容BIM设计,取得一定成果,为BIM技术在铁路工程中的应用积累了宝贵经验,也是我院利用BIM设计手段开展大型铁路工程设计的良好开端。     

浅谈大型盾构隧道施工监理工作

以上海长江隧道监理工作实践,谈大型盾构隧道监理工作要点及相关流程。本工程具有长、大、深的特点,而且为国内第一次下穿长江的大型盾构法公路隧道。     

基于大型自然灾害下生命线运输网络的可靠性研究

在大型自然灾害中,提高生命线运输网络的可靠性对应急救援、减少灾害损失和人员伤亡具有重要意义。本文研究生命线运输网络的可靠性,采用拓扑学的局部分散度、聚散度、节点孤立指数、路网可靠性因子等参数建立运输网络的可靠性评估模型,并通过成都到汶川生命线运输路网算例验证模型的有效性。     

破冰型大型航标船线型开发设计及破冰阻力评估研究

结合北海航海保障中心大型航标船的破冰功能需求,为本船选取合理的推进功率,对本船具有破冰功能特点的线型设计进行分析论述,同时运用破冰阻力经验公式对本船在一定冰厚和航速下的破冰阻力进行估算,结合冰池试验结果对破冰阻力数据进行对比分析,并进行冰区航行的快速性评估。     

大马力重载全驱大件牵引车分动箱油冷器设计及应用

大件牵引车是用于运输不可拆解的重型大件货物的专用车辆。其动力系统通常具有较大的马力和较高的扭矩。主要的运输工作过程中车辆处于长时间的重载工作情况,所以车辆在对与整车的动力及传动系统、冷却系统等方面的要求较高。而分动箱作为传动系统的重要组成部件,分动箱的性能对整车有着较为直接的影响。大件牵引车由于低速重载情况下长时间的工作,分动箱内的齿轮油发热严重产生高温,直接影响齿轮的性能及车辆的安全,故针对分动箱油温较高的情况,设计一套油冷器用于冷却分动箱油温,从而从根本上解决了车辆长时间处于低速重载作业过程中,分动箱油温较高对分动箱性能及齿轮使用寿命的不利影响。提高整车的可靠性和寿命,从而提高车辆的性能质量。     

Vulnerability analysis for large-scale and congested road networks with demand uncertainty

To assess the vulnerability of congested road networks, the commonly used full network scan approach is to evaluate all possible scenarios of link closure using a form of traffic assignment. This approach can be computationally burdensome and may not be viable for identifying the most critical links in large-scale networks. In this study, an “impact area” vulnerability analysis approach is proposed to evaluate the consequences of a link closure within its impact area instead of the whole network. The proposed approach can significantly reduce the search space for determining the most critical links in large-scale networks. In addition, a new vulnerability index is introduced to examine properly the consequences of a link closure. The effects of demand uncertainty and heterogeneous travellers’ risk-taking behaviour are explicitly considered. Numerical results for two different road networks show that in practice the proposed approach is more efficient than traditional full scan approach for identifying the same set of critical links. Numerical results also demonstrate that both stochastic demand and travellers’ risk-taking behaviour have significant impacts on network vulnerability analysis, especially under high network congestion and large demand variations. Ignoring their impacts can underestimate the consequences of link closures and misidentify the most critical links.     

Risk and reward in public transportation contracting

The workshop discusses and documents a number of countries’ experiences regarding risk and reward in the delivery of public transport and determines the way in which competitive pressures actually work (or not) to deliver efficient and effective services. Papers are grouped into three main themes, i.e., public versus private management; negotiated versus competitively tendered contracts; and measures to improve performance. This chapter begins with a brief overview of each of the eight papers. This is followed by a section that out the discussions that emanated from the papers. Finally, the main policy and research recommendations are presented.     

Total unimodularity and decomposition method for large-scale air traffic cell transmission model

In an earlier work, Sun and Bayen built a Large-Capacity Cell Transmission Model for air traffic flow management. They formulated an integer programming problem of minimizing the total travel time of flights in the National Airspace System of the United States subject to sector capacity constraints. The integer program was relaxed to a linear program for computational efficiency. In this paper the authors formulate the optimization problem in a standard linear programming form. We analyze the total unimodular property of the constraint matrix, and prove that the linear programming relaxation generates an optimal integral solution for the original integer program. It is guaranteed to be optimal and integral if solved by a simplex related method. In order to speed up the computation, we apply the Dantzig–Wolfe Decomposition algorithm, which is shown to preserve the total unimodularity of the constraint matrix. Finally, we evaluate the performances of Sun and Bayen’s relaxation solved by the interior point method and our decomposition algorithm with large-scale air traffic data.     

投标策略和报价技巧

论述了施工企业在投标过程中的几个主要环节,为施工企业参与投标,以及如何确定最优报价提供了参考依据.