多种创新分包成本控制方法在项目管理中的应用

结合中交一航局第五工程有限公司项目分包的管理实践,提出了“编制成本预控方案,明确分包项目最高限价;科学进行分包策划,合理划分分包工序;分包模式因地制宜,减少施工不可控成本;引进比选竞争机制,选择优质优价的分包商;推行分包管理责任书,提高分包合同严谨性;监督检查分包过程,保证成本控制及时性”等创新性成本分包控制方法,并对其实践应用效果进行了阐述。     

压盖松套伸缩接头的应用与优化

通过对压盖松套伸缩接头的结构与其在管路上的布置分析,优化选型与布置,有效减少管路连接法兰与分段合拢管的设置,节约造船成本,且利于伸缩接头本身的维护保养,可供船舶管路优化设计参考。     

野外自动值守数据站的电源设计与应用

根据野外自动值守的数据采集站的电源需求,结合当地的气象资料,给出电源系统的设计参数。针对设计参数,给出蓄电池容量的计算,考虑市场行情选取适当的蓄电池种类和规格;参考日照时数和影响因子,给出光伏发电系统的太阳能板功率原理计算,并参考地理纬度给出最佳安装角度;参考风情和影响因子,给出风力发电系统的风机功率原理计算;综合风、光参数,给出风光互补系统的太阳能板和风机功率的原理计算;同时给出三种发电方案的经济成本核算,做出最优选择。     

地铁盾构区间过硬岩段造价分析

盾构穿越普通软土地层的工程费用计算方法已趋成熟,但对于穿越硬岩段时却无统一明确的计价依据。通过对盾构过硬岩段采用盾构直接掘进,对岩层进行爆破+盾构掘进,矿山法开挖初期支护+盾构空推拼装管片,矿山法开挖初期支护并二次衬砌+盾构空推的4种施工方案分别进行技术探讨,并从工程造价角度对比分析,得出在几种可能的工程环境及条件下可采取的最优可行方案,以供参考。     

动力装置蒸汽预热供汽的多方案综合评估方法

目前的方案优选多属定性分析和经验决策,存在较大的主观随意性。为提高方案优选的准确性,首先从使用者角度出发,以使用者更为关心的蒸汽预热供汽系统完成特定任务的总体能力为核心,兼顾费用和风险对备选方案优选的约束作用,提出以“系统效能-费用-风险”为准则层的蒸汽预热供汽方案评估指标体系,然后按照系统综合评估的一般步骤,对评估指标进行量化与标准化处理,确定评估指标的权重,并完成评估指标的集成,最终得到5种蒸汽预热供汽备选方案的排序结果。评估结果表明,中压电极锅炉方案为最优方案。构建的评估指标体系、采用的评估方法以及备选方案的排序结果,可以为蒸汽预热供汽方案的论证与决策提供必要的理论依据。     

Reliability analysis of ovalized deep-water pipelines with corrosion defects

The accurate assessment of the remaining strength of corroded pipes is a subject that has been increasingly investigated over the past decades. This is because of the risk of significant social, economic, and environmental effects that may be caused by an accident. The finite element method has been successfully used to predict the collapse pressure considering external load. It was also used in this study. The literature primarily focused on the corroded pipes subjected to internal pressure. In this study, the out-of-roundness (ovalization) of the pipe was considered to evaluate the collapse pressure. Uncertainties should be incorporated into a computational model to assess the reliability of corroded pipes. Three methods for evaluation of the probability of failure were used: the first-order reliability method (FORM), traditional Monte Carlo (MC), and a new proposed methodology that combines MC results with the kernel density estimation method (MCkde). The probability of failure of ovalized corroded pipes subject to external pressure was computed. The results exhibited a good agreement between FORM and MCkde method. The statistical importance of each random variable was observed and the results were compared with those from intact ovalized pipes. The computation cost of the MC method with numerical simulation limits its use to the application under study. Solutions using the FORM and MCkde methods exhibited good agreement with those of the full MC method. However, the computational effort of the latter was independent of the stochastic dimension, and it was a derivative-free method. As expected, in general, the solutions based on empirical methods were conservative.     

Car sharing in Norwegian urban areas: Examining interest,intention and the decision to enrol

This article’s objective is to investigate the effects of sociodemographic and residential built environments, directly and indirectly through personality traits, attitudes and car ownership, on willingness to use car sharing in the case of Norway. This is done by examining multiple dimensions of the adoption process: the stated general interest and intention to participate in car sharing among non-members, as well as the decision to enrol as a car sharing user by comparing members to non-members. In this study, we analyse web survey data from 2414 residents from urban areas in Norway, using three structural equation models. Our findings indicate that the adoption of car sharing is complexly related to car ownership, with a noteworthy discrepancy indicating greater car sharing interest, but lower car sharing membership rates among car owners. We also find that environmental concerns exert a clear positive effect on all three dimensions of the adoption process. Being careful with money is linked negatively to interest and intention to participate, while being sociable and agreeable exerts no effect. Car sharers’ sociodemographic profiles are typically that of early adopters, but many of the effects, especially on interest, are mediated by car ownership, environmental consciousness and/or being careful with money, rather than directly on the sociodemographic profiles. Finally, we find car sharing to be more prominent in denser areas, but we did not discover a clear connection with access to public transport.     

A literature review of mobility services: definitions,modelling state-of-the-art,and key considerations for a conceptual modelling framework

ABSTRACT

This paper presents a comprehensive literature review focused on the supply side of mobility services, providing relevant insights at the conceptual, operational, and modelling levels. Definitions are first drawn from the Mobility as a Service paradigm due to its predominance in the literature. This is followed by an assessment of the operational features of a range of mobility services, including carsharing, bikesharing, ridehailing, and demand responsive transit. To conclude the review, the state-of-the-art in modelling approaches for mobility services is reported, at different levels of complexity and integration. Three of the most important findings and arguments from this paper suggest that a high degree of generality exists for operational features of mobility services; that it is essential to make a distinction between Mobility as a Service and a mobility service in isolation; along with the argument that human agency should be carefully considered in modelling efforts, both for user agent and driver agent decision-making processes. Finally, key considerations are proposed for the future development of a conceptual framework for modelling the supply side of mobility services, which would have a generic service provider model as its core component.     

公路工程建设项目成本控制探讨

结合实际工作经验，介绍公路工程建设项目成本控制的原则，并分析如何从项目投标、项目施工准备、项目施工过程、施工竣工结算四个方面对公路工程建设项目成本进行有效控制，以期为公路工程建设项目成本控制工作提供一定参考和借鉴。     

Estimating origin‐destination matrices from link volume counts: a simple intercity auto travel demand model for Sri Lanka

The cost of nation wide travel surveys is high. Hence in many developing countries, planners have found it difficult to develop intercity transportation plans due to the non availability of origin‐destination trip matrices. This paper will describe a method for the intercity auto travel estimation for Sri Lanka with link traffic volume data.

The paper outlines the rationale of selecting the district capitals of Sri Lanka as its “cities,” the methodology for selecting the intercity road network, determination of link travel times from express bus schedules and the location of link volume counting positions.

Initially, the total auto travel demand model is formulated with various trip purpose sub‐models. This model is finally modified to a simple demand model with district urban population and travel times between city pairs as the exogenous variables, to overcome statistical estimation difficulties. The final demand model has statistics within the acceptable regions.

The advantages of a simple model are discussed and possible extensions are proposed.