Bridge and tunnel toll elasticities in New York

In 1992, the authors carried out a statistical analysis of Triborough Bridge and Tunnel Authority (TBTA) crossings in New York City, to determine the impact of toll increases on traffic volumes and revenue. Using twelve years of monthly time-series data, we developed a set of multiple regression models that estimated traffic volumes on each TBTA bridge and tunnel as a function of the toll level and other explanatory variables. In most cases, the estimated toll elasticities were negative and much less than 1.0 in absolute value; the median toll elasticity for automobiles was found to be –0.10. Our finding that automobile travel demand is highly inelastic with respect to toll rates is consistent with most previous travel demand studies.     

考虑不确定性因素的路径优化(英文)

A route optimization methodology in the frame of an onboard decision support/guidance system for the ship’s master has been developed and is presented in this paper.The method aims at the minimization of the fuel voyage cost and the risks related to the ship’s seakeeping performance expected to be within acceptable limits of voyage duration.Parts of this methodology were implemented by interfacing alternative probability assessment methods,such as Monte Carlo,first order reliability method(FORM) and second order reliability method(SORM),and a 3-D seakeeping code,including a software tool for the calculation of the added resistance in waves of NTUA-SDL.The entire system was integrated within the probabilistic analysis software PROBAN.Two of the main modules for the calculation of added resistance and the probabilistic assessment for the considered seakeeping hazards with respect to exceedance levels of predefined threshold values are herein elaborated and validation studies proved their efficiency in view of their implementation into an on-board optimization system.     

控制船舶轴系纵向振动的动力吸振器参数优化研究(英文)

在船舶轴系中安装动力吸振器是减小船舶轴系纵向振动的有效方法,而动力吸振器的参数合理优化配置是控制轴系纵向振动的重要手段。将船舶轴系等效为多自由度系统,基于有限单元法建立船舶轴系纵向振动运动模型,并通过加装动力吸振器用于控制船舶轴系纵向振动。运用重分析方法求解轴系运动方程得到推力轴承处的力传递率和能量传递率,将二者作为评价动力吸振器对轴系振动控制效果的指标。在研究轴系响应频率范围内,提出将求解全局最优解较强的遗传算法与多目标优化算法相结合以优化动力吸振器参数;并且研究特定共振峰消减的参数优化问题。最后通过算例,比较不同目标函数以及动力吸振器不同安装位置对轴系纵向振动控制的影响,验证文中优化算法的可行性。     

线性需求下铁路客运差别定价模型研究

为提高席位资源利用率,研究了线性需求下我国铁路客运差别定价策略的优化模型。以收益最大化为目标,基于最优化理论和完全价格歧视策略,确定旅客群体最优细分数目以及每个旅客群体的最优票价,得出在客运淡季,铁路旅客最优细分数目为3~5个,各旅客群的最优票价由铁路客运市场细分数目决定。应用该模型为某城际高铁进行差别定价,试验结果表明,该模型可达到调节客流、增加收益的目的。     

基于广义费用函数的城际铁路分时定价策略研究

随着我国城市群的发展,区域内部各城市之间的客流需求不断增长,城际铁路作为城市间出行的主要方式,客流在高峰、低谷时段具有明显的不均衡性。为了更加平稳有序地提供高质量服务,充分发挥票价调节供需匹配关系的作用,对城际铁路分时定价策略进行研究,构建不同时刻、不同运输方式的旅客出行广义费用函数,建立双层规划模型,优化不同时段城际铁路票价,并结合Frank-Wolfe算法和带有惯性权重的粒子群算法,求解双层规划模型。最后,以京津城际铁路为例,验证了分时定价策略可以使客流分布更加均衡,并提高铁路运输部门收益。     

收费公路资产证券化定价及发行方法研究

从数据驱动视角出发，本文探讨收费公路资产支持证券的结构化定价方法。首先，构建反 映交通量风险特征的收费公路通行收入自回归积分滑动平均模型；其次，基于瀑布式偿付结构和 到期收益率Nelson-Siegel模型计算不同等级证券发债规模与息票利率；最后结合成渝高速和渝 蓉高速现实数据进行仿真分析。研究发现，高速公路成熟期的通行收入具有尖峰厚尾特征，成长 期的通行收入更兼具显著的波动聚集效应。数据驱动的定价模型能够刻画通行收入的风险特 征，合理估计优先级的证券融资比例，比只考虑利率风险的现金流折现法更具有优势；从发行方 式来看，合并发行的融资结构显著优于单独发行。管理启示是改变以单个高速公路项目为基础 的特许经营权融资，通过绩优绩差项目的合并发行优化融资结构。     

Joint deployment of charging stations and photovoltaic power plants for electric vehicles

The focus of this study is to jointly design charging stations and photovoltaic (PV) power plants with time-dependent charging fee, to improve the management of the coupled transportation and power systems. We first propose an efficient and extended label-setting algorithm to solve the EV joint routing and charging problem that considers recharging amount choices at different stations and loop movement cases. Then, a variational inequality problem is formulated to model the equilibrium of EV traffic on transportation networks, and an optimal power flow model is proposed to model the power network flow with PV power plants and optimally serve the EV charging requirements. Based on the above models for describing system states, we then formulate a model to simultaneously design charging stations, PV plants, and time-dependent charging fee. A surrogate-based optimization (SBO) algorithm is adopted to solve the model. Numerical examples demonstrate that the proposed SBO algorithm performs well. Additionally, important insights concerning the infrastructure design and price management of the coupled transportation and power networks are derived accordingly.     

Learning marginal-cost pricing via a trial-and-error procedure with day-to-day flow dynamics

This paper investigates the convergence of the trial-and-error procedure to achieve the system optimum by incorporating the day-to-day evolution of traffic flows. The path flows are assumed to follow an ‘excess travel cost dynamics’ and evolve from disequilibrium states to the equilibrium day by day. This implies that the observed link flow pattern during the trial-and-error procedure is in disequilibrium. By making certain assumptions on the flow evolution dynamics, we prove that the trial-and-error procedure is capable of learning the system optimum link tolls without requiring explicit knowledge of the demand functions and flow evolution mechanism. A methodology is developed for updating the toll charges and choosing the inter-trial periods to ensure convergence of the iterative approach towards the system optimum. Numerical examples are given in support of the theoretical findings.     

多目标最短路径模型及算法

为获得满足决策者需要的多目标最短路径问题的有效路径,建立了多目标最短路径模型,并提出了综合k-最短路径算法和多目标格序决策方法的多项式算法.该算法根据决策者可以接受的各单目标的上限,用k-最短路径算法,分别确定各单目标的可行路径集及其交集.再用多目标格序决策方法,比较交集中的有效路径,最终获得决策者满意的路径.     

序列成本定价机制的公理化分析

研究了序列成本定价机制对同质分配模型公理体系的满足情况，并着重探讨了该机制与上限性、下限性、免费午餐、需求可控性和一致性公理的关系．在同质模型的前提下，序列成本定价满足除去成本函数单调性、一致性和需求可控性之外的所有公理特性要求．比较了序列成本定价机制和平均成本定价机制满足上限性、下限性、免费午餐、需求可控性等公理的情况．结果表明，当代理人的需求不易控制时，平均成本定价具有明显优势；反之序列成本定价较好．