特长公路隧道避难联络通道间距设置研究

根据我国特长公路隧道交通流特性．运用避难行为理论对隧道内发生火灾等紧急事件后司乘人员的避难行为进行分析,在考虑司乘人员避难疏散所需的安全性最大与设施设置成本最低双重因素的约束下,结合多目标模型分析的透明化、合理化、弹性化等优点,可建立人身安全性最大与设施设置成本最低为目标的特长公路隧道避难联络通道间距设置模型,并运用该模型对我国第三长高速公路隧道雪峰山隧道避难联络通道设置间距提出最优值。工程实例表明,该模型能有效地指导符合我国国情的特长公路隧道避难联络通道间距的设置。     

一种新的代数多重网格法及其在CFD中的应用

提出了一种面向对象的代数多重网格(algebraic multi-grid,AMG)算法,以每一层网格作为研究单元.网格粗化过程中,形成各单元,同时记录其前后单元,形成双向链表.粗化过程采用Ruge和Stnben算法,光滑算子用Gauss-Seidel迭代.由于AMG算法与网格信息无关,可以作为"即插即用"型的线性方程组求解器.对CFD计算过程耗时最多的压力修正方程作了研究,分别对二维后台阶流动模型在不同网格划分情况进行了计算,代数多重网格方法与单重网格的不完全分解共轭梯度法对比发现,前者具有明显的优势.随着网格数目增加,优势表现更为明显.最后与AMG1r5相比,开发的程序内存占用较少,最高只有AMG1r5的36%.     

基于停车场限制的物流中心选址模型及算法

针对停车场限制的物流中心选址问题,建立了双层规划模型．上层规划以物流中心费用最小来确定物流中心的位置,下层规划建立了配送／采购车辆与城市道路交通组合分配模型,最后,采用遗传模拟退火算法对模型进行求解．     

Robust flight-to-gate assignment using flight presence probabilities

In this paper we present a novel method to improve the robustness of solutions to the Flight-to-Gate Assignment Problem (FGAP), with the aim to reduce the need for gate re-planning due to unpredicted flight schedule disturbances in the daily operations at an airport. We propose an approach in which the deterministic gate constraints are replaced by stochastic gate constraints that incorporate the inherent stochastic flight delays in such a way so as to ensure that the expected gate conflict probability of two flights assigned to the same gate at the same time does not exceed a user-specified value. The novel approach is integrated into an existing multiple time slot FGAP model that relies on a binary integer programming formulation and is tested using real-life data pertaining to Amsterdam Airport Schiphol. The results confirm that the proposed approach holds out great promise to improve the robustness of the FGAP solutions.     

Taxis in road pricing zone: should they pay the congestion charge?

This study aims at investigating the impact and feasibility of charging taxis with toll fee in the pricing zone when designing congestion pricing scheme. A bi‐level programming model is developed to compare the maximum social welfares before and after the congestion charge is imposed on taxis. The lower level is a combined network equilibrium model formulated as a variational inequality program, which considers the logit‐based mode split, route choice, elastic demand, and vacant taxi distributions. The upper level is to maximize the social welfare when toll rates vary. The bi‐level problem can be solved by the genetic algorithm, whereas the lower level is solved by the block Gauss–Seidel decomposition approach together with the method of successive averages and diagonalization algorithm. An application with numerical examples is conducted to demonstrate the effectiveness of the proposed model and algorithm and to reveal some interesting findings. Copyright © 2014 John Wiley & Sons, Ltd.     

基于海上航道单幅图像去雾方法

基于海上航道单幅图像去雾方法的研究在海上航道施工领域具有广阔的应用前景。提出一种基于天空区域分割的单幅海面图像去雾方法,并与传统方法在时间、图像清晰度方面进行对比,结果表明：该方法相较多尺度Retinex、暗通道优先、CLAHE等传统的去雾方法具有一定优势。     

Increasing the accuracy of loop detector counts using adaptive neural fuzzy inference system and genetic programming

Loop detectors are devices that are most commonly used for obtaining data at intersections. Multiple detectors are usually required to monitor a location, and this reduces the accuracy of detectors for collecting traffic volumes. The purpose of this paper is to increase the accuracy of loop detector counts using Adaptive Neural Fuzzy Inference System (ANFIS) and Genetic Programming (GP) based on detector volume and occupancy. These methods do not need microscopic analysis and are easy to employ. Four approaches for one intersection are used in a case study. Results show that the models can improve intersection detector counts significantly. Results also show that ANFIS produces more accurate counts compared to regression and GP.     

上海轨道交通1号线对城市空间扩散的影响

运用地理信息系统技术,解析上海市近15年的城市形态演变遥感图片,描述其城市外围扩散特征为:圈层式扩散、轴线突破扩散以及郊区集镇吞噬扩散.同时发现上海市轨道交通1号线在过去的10年间引导了沿线的带状城区扩散,吸引了大量的居住空间的分布.结合交通与城市土地利用的互动关系,从城市扩散动力、城市交通系统以及城市扩散模式三个层面在理论上分析交通在城市外围扩散中的导向作用.指出城市轨道交通诱导城市形态发展的前提条件是:充分发挥自身的交通客运能力.     

复合功率分流系统发动机起动H∞鲁棒优化控制

为改善复合功率分流混合动力系统纯电动至混合动力模式切换过程的车辆驾驶平顺性,同时确保在模型不确定和外部干扰条件下切换控制的鲁棒性,本文中提出了一种发动机起动H∞鲁棒控制策略。首先,建立复合功率分流混合动力系统动力学模型,并对纯电动至混合动力模式切换过程进行分析。其次,以车辆驾驶平顺性和发动机起动时间为优化指标,通过动态规划求解发动机最优拖转转速曲线。然后,考虑到输入轴阻尼参数摄动、驾驶员输入、道路负载、输出端转速的不确定性变化和发动机转速量测噪声的干扰,设计了发动机起动H∞鲁棒控制器。最后,通过离线仿真和台架试验对所提出的控制策略进行验证。结果表明,该策略能有效将冲击度降低至11.52 m/s^3以内,同时对模型不确定性和外部干扰有较强的抑制能力。     

一种货运列车节能优化方法研究

研究了一种货运列车节能优化方法.首先以列车运行时间为约束,建立列车节能运行优化模型.设计了一种基于极大值原理的动态规划算法,在满足运行时间约束下,实现列车最优节能运行操纵策略优化.本算法仅仅对速度进行离散化处理,相比其他方法需对位置和速度进行双重离散,避免因网格划分引起的速度轨迹波动,同时提高了计算效率.此外,该算法将...