路边停车场管理系统的研究和实现

针对智慧城市建设对智能交通的需要,设计了一种基于物联网技术的智能路边停车场管理系统;该系统采用地磁传感器作为信息采集设备,利用ZigBee和GPRS无线通信技术实现数据的远程传输;应用MySQL数据库、tomcat 6.0服务器搭建后台信息管理服务器,实现对多个路边停车场的统一管理;实地测试表明,系统稳定可靠,检测准确率达到了98%,成功实现了信息的实时及时发布和智能化管理,可以应用于实际的城市路边停车场管理。     

城市中心区内停车价格对出行行为的影响分析

本文通过对北京市中心区早高峰时段小汽车出行者和公共交通出行者出行方式选择意向调查,采用多项Logit模型,分析中心区停车价格变化对小汽车出行向公共交通出行方式的转移行为的影响.预测结果表明不同出行目的对停车价格的敏感程度也不同,在提高公共交通服务水平的前提下,加大中心区停车收费标准,会使小汽车出行有较大比例的转移.     

辅助光注入下半导体光放大器的快慢光性能

随着全光网络的快速发展,快慢光技术受到了广泛关注。为了研究半导体光放大器(SOA)的快慢光效应,文章构建了辅助光注入半导体光放大器的理论模型。比较了辅助光注入SOA前后,直流电流、调制电流、调制频率、相移以及增益系数等参数对相位延时量的影响。仿真结果表明：辅助光的注入使输出信号光由慢光变为快光,辅助光功率越强,效果越明显。同时,注入辅助光信号后,直流电流越大,相位延时量越大;调制电流、调制频率、相移及增益系数越大,相位延时量越小。     

基于物联网的智能停车场系统研究

自改革开放以来,人民的生活水平得到了有效改善,汽车这一高消费交通用具已逐渐普及到户.但是大量的汽车在国内尤其是大中型城市中停车已成为严重的问题.物联网智能停车场以先进的现代技术以百万摄像机抓拍车牌读取车辆信息进而有效的让车主进出停车场,提高停车效率.     

城市立体停车场管理信息系统设计

为缓解城市停车难问题,建设高效的城市立体停车场已成为共识.本文详细分析了城市立体停车场的停车流程及其管理需求,设计城市立体停车场的硬件框架架构和管理软件模块,基于组件式开发技术开发了该系统,对城市立体停车场管理的便捷化、信息化和智能化具有实际指导意义.     

A low-cost wireless sensors positioning solution for indoor parking facilities management

A relatively low-cost system for indoor parking facilities management is proposed, which is a combined solution of RFID/WiFi and a MEMS IMU monitoring scheme. An RFID localisation module is proposed in the form of so-called virtual gates. To define such virtual gates, either RFID tags or readers are placed at known locations throughout the area of interest. In this study, a number of tags are fixed at known positions and a moving reader is carried by each participating vehicle. Based on this configuration set-up, the Cell of Origin (CoO) technique is applied, in which the system indicates the presence of the user carrying the reader in a cell around the tag location. To define a virtual gate, tags are installed along the parking lot corridors and at critical transit passages in the parking facility. The CoO technique is also proposed in the case of WiFi for location determination of vehicles in a multi-storey car park. In this study, WiFi is employed to monitor the passing vehicles and bridge the gap until a tag can detect a user’s reader again. Thus, a combined positioning solution of RFID and WiFi is achieved. As a complement to the proposed RFID/WiFi system, this study examines the potential and limitations of MEMS IMU sensors (i.e. accelerometers, gyroscopes and barometers) commonly found in modern smartphones. The paper concludes with a detailed discussion on the implications of alternative positioning techniques for indoor parking management.     

Surface modification of a titanium alloy with a phospholipid polymer prepared by a plasma-induced grafting technique to improve surface thromboresistance

To improve the thromboresistance of a titanium alloy (TiAl₆V₄) surface which is currently utilized in several ventricular assist devices (VADs), a plasma-induced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) was carried out and poly(MPC) (PMPC) chains were covalently attached onto a TiAl₆V₄ surface by a plasma induced technique. Cleaned TiAl₆V₄ surfaces were pretreated with H₂O-vapor-plasma and silanated with 3-methacryloylpropyltrimethoxysilane (MPS). Next, a plasma-induced graft polymerization with MPC was performed after the surfaces were pretreated with Ar plasma. Surface compositions were verified by X-ray photoelectron spectroscopy (XPS). In vitro blood biocompatibility was evaluated by contacting the modified surfaces with ovine blood under continuous mixing. Bulk phase platelet activation was quantified by flow cytometric analysis, and surfaces were observed with scanning electron microscopy after blood contact. XPS data demonstrated successful modification of the TiAl₆V₄ surfaces with PMPC as evidenced by increased N and P on modified surfaces. Platelet deposition was markedly reduced on the PMPC grafted surfaces and platelet activation in blood that contacted the PMPC-grafted samples was significantly reduced relative to the unmodified TiAl₆V₄ and polystyrene control surfaces. Durability studies under continuously mixed water suggested no change in surface modification over a 1-month period. This modification strategy shows promise for further investigation as a means to reduce the thromboembolic risk associated with the metallic blood-contacting surfaces of VADs and other cardiovascular devices under development.     

一种MIMO-OFDM信道混合估计方法

传统的信道估计方法往往假设多径分量数已知且为常数,粒子滤波算法可估计服从高斯分布的时变信道。实际无线环境中,多径分量数目与幅度皆为时变,则粒子滤波估计方法性能恶化。本文提出基于二进制粒子群算法和卡尔曼滤波的MIMO-OFDM信道混合估计方法。采用随机集建模MIMO信道,并分析得到其多径转移概率模型;基于此模型将信道分解为离散部分和连续部分,推导得到此两部分与整体信道关系;采用二进制粒子群算法拟合信道离散部分,利用卡尔曼滤波估计信道幅度,将利用信道估计计算得到的观测值与真实观测值的近似程度作为适应度函数。仿真结果表明:本文所提出的信道估计方法性能优于基本粒子滤波的信道估计方法。     

停车场规划的分片凸规划-建模、算法及应用

本研究停车场选址问题。本抓住主要矛盾，建立实用停车场选址的分片凸规划模型。设计往复调整、下降迭代相结合的算法。并在常州市交通管理规划应用中取得了良好的效果。     

地方性城市静态交通现状特征与优化研究——以杭州市萧山城区为例

针对地方性城市“停车难、乱停车”等静态交通问题,以杭州市萧山区为例,对其城区各类停车设施的分布状况与利用现状进行分析,认为城市静态交通设施总量不足、设施结构不合理和停车秩序混乱是其主要问题所在,并据此对地方性城市静态交通困境产生的原因进行剖析,提出静态交通建设对策及在萧山城区的具体优化措施．