物联网在公路运输业的应用探讨

对物联网在公路运输业中的应用进行探讨,通过射频识别、红外感应器等将车辆与物品的信息记录下来,并随着车辆运输行进过程辅以GPS与G IS技术,对车辆位置与物品位置进行有效跟踪,为查询车辆交通信息与物品运输实时信息提供帮助,从而提高公路运输服务能力和水平,降低物流成本。     

建设项目设计阶段造价控制对策分析

该文阐述了在建设项目全过程造价控制流程中,设计阶段造价控制是其中一个尤为重要的关键环节。在各个设计阶段通过设计方案优化、施行限额设计、采用设计施工总承包体制等方式进行有效的造价控制,是合理控制建设项目造价,节约建设投资的重要途径。     

保定市污水处理厂二期工程配套管网设计

该文介绍了保定市排水设施的现状及存在的问题,对管网系统布局、污水量预测及管材选择等提出了设计方案,并就城市排水管网设计提出了建议。     

浅议加强设计阶段建设项目工程造价的控制

项目立项后对项目造价的控制的关键在于设计阶段。该文先介绍了一些设计阶段造价控制存在的不足,而后提出了关于加强设计阶段工程造价控制的一些想法。     

精确制导武器对地面目标毁伤效能研究

从对地攻击靶场效能评估的角度出发,讨论了制导武器毁伤地面目标效能的模型、所采用的效能指标及效能指标的计算方法,最后给出了一个对单个目标毁伤效能的算例分析。     

基于排队论的舰艇编队网络化协同防空效能分析

通过排队论的方法,研究了舰艇编队网络中心化防空作战体系,建立效能评估模型,为决策提供了理论依据。     

Bus congestion, optimal infrastructure investment and the choice of a fare collection system in dedicated bus corridors

Microeconomic optimisation of scheduled public transport operations has traditionally focused on finding optimal values for the frequency of service, capacity of vehicles, number of lines and distance between stops. In addition, however, there exist other elements in the system that present a trade-off between the interests of users and operators that have not received attention in the literature, such as the optimal selection of a fare payment system and a designed running speed (i.e., the cruising speed that buses maintain in between two consecutive stops). Alternative fare payment methods (e.g., on-board and off-board, payment by cash, magnetic strip or smart card) have different boarding times and capital costs, with the more efficient systems such as a contactless smart card imposing higher amounts of capital investment. Based on empirical data from several Bus Rapid Transit systems around the world, we also find that there is a positive relationship between infrastructure cost per kilometre and commercial speed (including stops), achieved by the buses, which we further postulate as a linear relationship between infrastructure investment and running speed. Given this context, we develop a microeconomic model for the operation of a bus corridor that minimises total cost (users and operator) and has five decision variables: frequency, capacity of vehicles, station spacing, fare payment system and running speed, thus extending the traditional framework. Congestion, induced by bus frequency, plays an important role in the design of the system, as queues develop behind high demand bus stops when the frequency is high. We show that (i) an off-board fare payment system is the most cost effective in the majority of circumstances; (ii) bus congestion results in decreased frequency while fare and bus capacity increase, and (iii) the optimal running speed grows with the logarithm of demand.     

Assessing the cost of transfer inconvenience in public transport systems: A case study of the London Underground

Few studies have adequately assessed the cost of transfers² in public transport systems, or provided useful guidance on transfer improvements, such as where to invest (which facility), how to invest (which aspect), and how much to invest (quantitative justification of the investment). This paper proposes a new method based on path choice,³ taking into account both the operator’s service supply and the customers’ subjective perceptions to assess transfer cost and to identify ways to reduce it. This method evaluates different transfer components (e.g., transfer walking, waiting, and penalty) with distinct policy solutions and differentiates between transfer stations and movements.The method is applied to one of the largest and most complex public transport systems in the world, the London Underground (LUL), with a focus on 17 major transfer stations and 303 transfer movements. This study confirms that transfers pose a significant cost to LUL, and that cost is distributed unevenly across stations and across platforms at a station. Transfer stations are perceived very differently by passengers in terms of their overall cost and composition. The case study suggests that a better understanding of transfer behavior and improvements to the transfer experience could significantly benefit public transport systems.     

A topological route choice model for metro

This article presents a route choice model for public transit networks that incorporates variables related to network topology, complementing those found in traditional models based on service levels (travel time, cost, transfers, etc.) and users’ socioeconomic and demographic characteristics (income level, trip purpose, etc.). The topological variables represent concepts such as the directness of the chosen route and user knowledge of the network. For both of these factors, the necessary data is endogenous to the modelling process and can be quantified without the need for information-gathering beyond what is normally required for building route choice models. Other novel variables in the proposed formulation capture notions of user comfort such as vehicle occupancy rates and certain physical characteristics of network stations. We conclude that these new variables significantly improve the explanatory and predictive ability of existing route choice specifications.     

有限经济批量和库存的模拟退火算法

研究在一个简单供应链中的生产批量和配送计划问题。解决在供应链中减少单位时间库存、设备和运输的平均成本生产批量及运送计划。假设所有影响因素如产品需求率都已限定在有限的计划范围内,利用模拟退火算法具有的较强局部搜索能力特性弥补传统算法的不足,计算结果表明SA算法能够找到问题的最优解或近似最优解,是解决该问题的有效方法。