基于价值工程的全生命周期趸船材质方案比选研究

将趸船整个生命周期过程中的技术先进性、经济合理性和环境协调性有机地融合为一体,基于价值工程理论提出趸船材质方法比选。实例表明在千岛湖这样的大吨位船舶碰撞概率很小的水域,采用混凝土趸船明显优于钢质趸船。     

A logit-based model for measuring the effects of transportation infrastructure on land value

Mutual interactions between transportation and land use have long been debated. Despite progress made in computational technology, the study of these interactions is not adequately developed. The most important aspect of such interactions is given by the changes in land values due to changes in transportation infrastructures. We consider the behavioural features of these interactions along with the constraints on the land and/or zoning restrictions and propose a reliable model for the first time to predict land value changes with respect to changes in transportation facilities and accessibility. The proposed model is a logit-based mathematical programming methodology where the relative price of land is predicted with respect to transportation accessibility, neighbourhood amenities, location premium, availability of land, and zoning regulations. A real-world case study is used to exhibit the applicability of the proposed methodology and demonstrate the efficacy of the algorithms and procedures.     

Robust traffic assignment model: Formulation,solution algorithms and empirical application

ABSTRACT

The deterministic traffic assignment problem based on Wardrop's first criterion of traffic network utilization has been widely studied in the literature. However, the assumption of deterministic travel times in these models is restrictive, given the large degree of uncertainty prevalent in urban transportation networks. In this context, this paper proposes a robust traffic assignment model that generalizes Wardrop's principle of traffic network equilibrium to networks with stochastic and correlated link travel times and incorporates the aversion of commuters to unreliable routes.

The user response to travel time uncertainty is modeled using the robust cost (RC) measure (defined as a weighted combination of the mean and standard deviation of path travel time) and the corresponding robust user equilibrium (UE) conditions are defined. The robust traffic assignment problem (RTAP) is subsequently formulated as a Variational Inequality problem. To solve the RTAP, a Gradient Projection algorithm is proposed, which involves solving a series of minimum RC path sub-problems that are theoretically and practically harder than deterministic shortest path problems. In addition, an origin-based heuristic is proposed to enhance computational performance on large networks. Numerical experiments examine the computational performance and convergence characteristics of the exact algorithm and establish the accuracy and efficiency of the origin-based heuristic on various real-world networks. Finally, the proposed RTA model is applied to the Chennai road network using empirical data, and its benefits as a normative benchmark are quantified through comparisons against the standard UE and System Optimum (SO) models.     

柴油发动机掺烧生物柴油的经济性研究

为了更好地评价柴油机燃用生物柴油的经济性,分析了生物柴油和0#石化柴油的理化性质,分别对生物柴油的体积分数为0.2,0.5,1的B20、B50、B100 3种燃料和0#柴油在495Q3柴油机上进行了试验。试验结果显示燃用3种燃料的燃油消耗率比0#柴油在中小负荷时平均增加5.30%,9.65%,19.04%,大负荷时平均增加2.86%,4.75%,9.64%;能量等值折合油耗率在中小负荷时平均增加2.65%,2.63%,5.74%,大负荷时平均降低0.26%,1.97%,4.80%。     

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飞机多机种出动架次率是衡量飞机作战效能的重要指标,本文对空军场站军用飞机多机种（型）出动架次率进行了研究。通过对飞机出动回收过程的描述,基于排队理论建立多服务器多服务率的飞机多机种（型）出动回收网络模型,并采用扩展后的平均值分析对飞机出动能力进行了求解。通过解析计算,给出飞机多机种（型）出动架次率曲线,分析架次率与飞机数量之间的关系,并结合平均队长、利用率等系统性能指标,识别出制约飞机多机种（型）出动架次率提高的因素。最后通过蒙特卡洛仿真对构建的回收网络模型的计算结果进行验证。验证结果表明,飞机多机种（型）出动网络模型及其算法适合应用于实践中,并且有助于对空军场站飞机多机种（型）出动能力的研究。     

中国铁路提速后技术进步对产出贡献的测算

选取我国铁路提速后1997~2007年间的相关数据,采用基于科布——道格拉斯生产函数的Solow余值法,将有限分布滞后模型和半参数回归模型引入计算模型,对数据进行拟合,计算得到铁路提速后技术进步、固定资本投入以及人力资本投入对产出的贡献率,并根据计算结果提出促进我国高速铁路建设的相关对策建议.     

试论交通运输行业核心价值体系建设的重要意义与时代内涵

建设交通运输行业核心价值体系具有重大的现实意义.交通运输行业核心价值体系的时代内涵可以概括为“献身交通、服务大众、四海为家、扎根基层、吃苦实干和默默奉献”.建设交通运输行业核心价值体系,是一项复杂的系统工程和长期的战略任务.     

基于结构可靠度的在役桥梁剩余价值分析

在BOT的交通基础设施建设模式下，转交政府相关部门后的基础设施从会计学的角度而言已经摊销完毕，但是从经济学角度而言。这些公共基础项目仍然发挥作用．产生着经济效益。对在役桥梁进行剩余价值分析，对于路政部门加强桥梁维护维修、加固甚至新建等决策管理都有实际意义。基于可靠度理论提出了一种折旧方法并用其进行剩余价值计算，为公共项目建设宏观经济的成本分析提供一种量化的工具。     

安龙铺隧道开挖过程动态数值模拟分析

以沪瑞国道主干线(贵州境)镇宁—胜境关高速公路安龙铺隧道为工程背景,利用有限元分析程序,对中壁CRD开挖法进行了数值模拟,分析研究开挖过程中隧道围岩应力场和位移场的变化。     

油库安全阀的选用参数计算和确定方法

阐述了油库常用安全阀排量、口径、开启压力的计算和确定方法,重点分析了油库和机场特定部位安全阀开启压力和公称通径的计算过程和考虑要素,并说明了安全阀定购和使用中的注意事项.