城市道路交叉口行人过街交通设计方法

交叉口是城市道路交通中各种交通参与方式的交汇点,也是交通行为的冲突点和交通事故的多发点。合理的行人过街交叉口设计是保障行人过街安全、提高交叉口通行效率的前提。在对交叉口行人过街常见问题分析的基础上,提出了道路交叉口行人过街交通设计原则与方法。     

The effects of on‐street parking on the service rate of nearby intersections

An on‐street parking maneuver can often start a temporary bottleneck, leading to additional delay endured by the following vehicles. If the maneuver occurs near a signalized intersection, the service rate of the intersection might be reduced. In this paper, a model is built to analyze the effects of parking maneuvers on the intersection service rate. Based on the hydrodynamic theory of traffic flow, the perturbation caused by the parking maneuver is analyzed. Using dimensional analysis, we illustrate the relation between the background conditions, the distance from the parking area to the intersection, and the intersection service rate. Based on this relation, one can compute the service rate reduction caused by existing on‐street parking areas. A minimum distance between the parking area and the intersection to avoid such reduction can be accordingly found. Numerical examples based on empirical data from the city of Zurich, Switzerland, are provided to illustrate the practical applications. Although the analysis is based on streets with a single lane per direction, the findings can provide some insights regarding different situations. We hope such findings can be used as a basis for developing on‐street parking design guidelines. Copyright © 2015 John Wiley & Sons, Ltd.     

关于二次过街方式定量分析方法的研究

本文利用交通仿真软件TRANSYT 7F和行人延误模型分析主干路和次干路相交的交叉口上设置二次过街方式前后对交叉口最佳周期长度、车辆延误及行人延误的影响。通过比较分析 ,提出了二次过街方式的定量分析方法。     

精细化设计街道整体空间环境——以南昌市象山路综合改造工程为例

在城市建设品质要求越来越高的背景下，针对南昌市象山路街道存在的问题和自身特点，从街道的交通环境、设施环境和周边环境3个部分着手，精细化设计街道整体空间环境，提出了非机动车等候区设置、双向错位人行横道布置、多杆合一布置、街道设施融入特色文化符号、强弱电箱柜隐形化处理、街道周边空间精细化协调衔接等处理方案，为街道沿线居民创造了一个以人为本、交通便利、休闲舒适的生活空间，同时也可为类似的旧城区街道改造提供参考经验。     

Intelligent VIV control of 2DOF sprung cylinder in laminar shear-thinning and shear-thickening cross-flow based on self-tuning fuzzy PID algorithm

A self-tuning fuzzy PID (ST-FPID) control scheme is implemented within a joint interactive (Matlab/Simulink/Fluent) co-simulation framework for effective two degrees of freedom (2DOF) vortex-induced vibration (VIV) control of an elastically-mounted circular cylinder in laminar cross-flow of incompressible non-Newtonian power-law fluids based on the control action of a single transverse force actuator. The model-free controller, which systematically tunes the control parameters online in real time based on given rules, is well-known to be highly advantageous over the previously employed conventional PID controllers. It is particularly capable of handling the intricate non-linear dynamic effects inherent in the complex fluid rheology of non-Newtonian flow past the cylinder in presence of unmodeled system dynamics, high parametric uncertainties, diverse operational conditions, and time-varying external disturbances and control signals. Extensive numerical simulations reveal that the complex shear-thinning and shear-thickening behaviors of fluid viscosity can substantially influence the cylinder dynamic response, applied hydrodynamic forces, and flow structure. In particular, effectiveness and high performance of the adopted ST-FPID control strategy in substantial suppression of the high amplitude coupled 2DOF VIV of the elastically-mounted cylinder at selected critical reduced velocities in the lock-in region are established for a wide range of power-law index parameters (e.g., up to 83% reduction in RMS value of cylinder cross-flow displacement and up to 35% reduction in RMS value of cylinder in-line displacement for n=1and U* = 5 at Re = 100). Also, the vigorous action of the error-driven ST-FPID controller in forcing the high strength vortex shedding patterns of the uncontrolled cylinder out of the lock-in condition into the classical von Kármán vortex street of 2S-type mode of moderately weaker strengths is verified.     

基于改进遗传算法的城市街道空间布局优化研究

为了优化城市街道的空间分布，提出了一种基于改进遗传算法的城市街道空间布局优化方法。搭建城市街道空间布局模型，设置街道空间布局优化约束条件，通过优化编码过程完成遗传算法改进，利用改进后的遗传算法从市政、景观、专项设置和建筑4个方面制定城市街道空间布局优化方案。以盐城市文港路街区改造项目为例，按照新的布局优化思路完成改造。从总评分上看，优化前城市街道空间布局评分处于[0.5，0.7)区间，说明此时的街区空间布局能够基本满足期望。优化后城市街道空间布局评分处于[0.9，1.0]区间，说明此时的城市街道空间布局较为优秀，该方法的城市街道空间布局优化效果好。