The suitability of hedonic models for cost-benefit analysis: Evidence from commuting flows

We compare two estimates of benefits arising from the construction of new bridges in south-west Norway. One estimate comes from a hedonic property value model. Rather than follow an approach which is strictly theoretically correct, we adopt Rosen’s simple first-stage approach. To investigate and validate whether this simplified approach gives a reasonable estimate, we compare it to an estimate derived from a travel demand model. We find that a variant of an ex post hedonic house price model gives very similar estimates to the estimates from the travel demand model. This supports a hypothesis that the simplistic hedonic approach is reasonable.     

Using OMP analysis to observe temporal variability in water mass distribution

Previous optimum multiparameter analyses have investigated spatial distribution of water masses and reported successful results. This study tests the method further with application to a time series to examine temporal variability in water mass distribution. Observations collected from the Sargasso Sea are utilised, mainly to detect well-documented property changes that have occurred in Labrador Sea Water, but also possible fluctuations in water mass contributions as a whole.The results show much structure and variability in the contributions of Central Water and upper deep waters in the depth range 900–2000 m. It is proposed that the passage of warm and cold core eddies is indicated by these changes in relative contributions of water masses, although quantitative comparison of satellite altimetry data with the model results is not conclusive.Significant irregularities in the distribution of Labrador Sea Water are also revealed by the model. Through-flow of modified (since the early 1990s) Labrador Sea Water is denoted in the results by an apparent absence from mid-1995 to early 1998. This suggests a transit time of 5–6 years between the Labrador Sea and Bermuda, which is consistent with observational findings described in the literature.     

土木规划的规划环境与规划政策研究

研究目的：土木规划是以社会公共基础设施为对象，本着统筹、系统的思想，利用土木工程技术与系统科学方法进行的规划。但就我国目前土木规划领域的现状来看，无论是在“规划环境”方面还是“规划政策”方面，都存在着一定的问题。本文的目的在于通过对我国土木规划的规划环境与规划政策的研究，促进土木规划在我国的科学化、体系化发展。研究方法：本文聚焦于我国的交通基础设施，系统地整理和分析了我国土木规划的历史与现状，包括政府与市场的角色定位、规划体制、法律法规的情况，同时介绍了国外的经验，揭示了存在的问题。研究结果：提出我国要走科学的“土木规划”道路，在规划环境上应改革规划体制，完善立法，建立多层次的基础设施体系；在规划政策上应努力拓宽资金渠道，加强综合规划等。研究结论：揭示了在我国开展土木规划研究的重要性和必要性，土木规划相关研究的不断深入，必将促进我国的土木规划水平的提高。     

新型多粒度物理帧时槽交换技术

在分析现有的基于DWDM的多粒度交换技术存在问题的基础,提出了一种基于DWDM的、能够保证服务质量的新型的多粒度交换技术———物理帧时槽交换技术(Physical Frame Time slot Switching, PFTS)。文中给出了PFTS的帧结构,对PFTS的工作过程和特点以及PFTS的服务质量保证机制进行了讨论。最后将PFTS与近年文献中报道较多的多粒度光突发数据块交换———OBS(Optic Burst Switching)进行了比较。仿真结果表明:在保证服务质量的前提下,PFTS的信道利用率明显高于OBS。     

干燥细砂破坏形式试验分析

土体破坏不是偶然的现象,受控于多种因素,而这些因素均为变量,不能精确地知道它们的数值。土体的结构是指土颗粒或集合体的大小和形状、表面特征、排列形式及它们之间的连接特征,也是影响土体破坏的多种因素之一。文章通过模型试验发现细砂的破坏是多种形式的综合体,其中土体的密实度、颗粒大小、级配等均是影响土体破坏形式的重要因素。     

关于海事基础设施建设中的招投标管理

工程造价管理,贯穿于海事基础设施建设的全过程。而招投标阶段的造价控制,不仅能有效消除因项目前期深度、设计精度问题带来的造价不确定因素,也会为施工阶段的造价控制打下良好的基础,作者通过对影响招标投标阶段工程造价诸多因素的分析研究,提出有效控制工程造价的方法和建议,供广大同行参考。     

铁路智能运输系统结构设计方法

铁路智能运输系统(RITS)结构设计的实质就是确定RITS由逻辑框架到物理框架的映射关系。RITS是由若干要素组成的,选择RITS结构设计的要素,其中具有逻辑属性的要素是功能,具有物理属性的要素是子系统。收集来自体系框架中专家的知识经验,确定子系统和功能的对应关系。建立功能要素集合与子系统要素集合之间的关联矩阵、关联强度矩阵及其可达矩阵,从而确定系统的结构。RITS结构设计实例选取11个子系统和21个功能域作为设计要素,通过RITS结构设计方法以及模糊聚类方法对物理子系统进行重新划分,得到合理的物理子系统划分结果。     

Manufacturing Technology for the Mould of Plastic Cushion for Motorcycle Pedal

摩托车设计随着社会的发展更加人性化,外塑件的曲面也越来越复杂,在外塑件的曲面制作中越来越多地利用二次曲线、样条曲线等复杂的多阶函数曲线作为轮廓线或控制线来编辑曲面;在模具制作过程中,需要进行展开制作的踏皮等零件,如果设计者不提供展开的数据模型,制造者用手工测量进行展开的误差较大,需要进行修模修整,失去了3D设计的意义。     

快速路与邻接交叉口分散换道和速度引导方法

研究车路协同城市快速路与邻接交叉口主线分散换道和速度引导自适应控制方法. 对高饱和度入口匝道与邻接交叉口，提出主线分散换道自适应控制方法，依据合流区上游不同车道密度制定换道规则，以主线流量最大化为目标确定邻接交叉口相位相序；对出口匝道存在超长排队，提出主线速度引导自适应控制方法，依据主线上游车辆目的地确定速度引导策略，以出口匝道需求与通行能力相匹配为目标确定出口匝道关联相位优先权. 采用元胞自动机模型仿真验证，结果表明，所提方法与非协调控制、传统协调控制、车路协同交叉口自适应控制相比，区域流量分别提高17.38%、5.52%、10.06%，总时间消耗分别下降35.86%、 26.21%、17.39%.     

The underground economy: Tracking the higher-order economic impacts of the São Paulo Subway System

Over one million workers commute daily to São Paulo City center, using different modes of transportation. The São Paulo subway network reaches 74.2 km of length and is involved in around 20% of the commuting trips by public transportation, enhancing mobility and productivity of workers. This paper uses an integrated framework to assess the higher-order economic impacts of the existing underground metro infrastructure. We consider links between mobility, accessibility and labor productivity in the context of a detailed metropolitan system embedded in the national economy. Simulation results from a spatial computable general equilibrium model integrated to a transportation model suggest positive economic impacts that go beyond the city limits. While 32% of the impacts accrue to the city of São Paulo, the remaining 68% benefit other municipalities in the metropolitan area (11%), in the State of São Paulo (12.0%) and in the rest of the country (45%).