Remote Video Sensing of Highway Pavements at Road Speeds: Using the Motorola 68020 Microprocessor

This article presents microprocessor measurement techniques for a multi-cameera video system mounted in a van type vehicle that will observe a 12-foot lane of road surface. Because of the high speed processing requirement of the vision system, several 68020 microprocessors are employed to handle data and detect various cracking patterns while the vehicle is in motion at highway speeds. As the image processing system collects the data, a host microprocessor computes an instantaneous and cumulative pavement score that will be used by the operator and the Pavement Management System, PMS, for further analysis and maintence considerations. The article presents an overview of the microprocessor driven PMS using high speed hardware circuitry for real-time processing. Development of the system is underway by the Earth Technology Corporation and Louisiana Tech University.     

Collecting comprehensive traffic information using pavement vibration monitoring data

Traffic data is essential for intelligent traffic management and road maintenance. However, the enormous effort used for data collection and analysis, combined with conventional approaches for traffic monitoring, is inefficient due to its high energy consumption, high cost, and the nonlinear relationships among various factors. This article proposes a new approach to obtain traffic information by processing raw data on pavement vibration. A large amount of raw data was collected in real time by deploying a vibration‐based in‐field pavement monitoring system. The data was processed with an efficient algorithm to achieve the monitoring of the vehicle speed, axle spacing, driving direction, location of the vehicle, and traffic volume. The vehicle speed and axle spacing were back‐calculated from the collected data and verified with actual measurements. The verification indicated that a reasonable precision could be achieved using the developed methods. Vehicle types and vehicles with an abnormal weight were identified by a three‐layer artificial neural network and the k‐means++ cluster analysis, respectively, which may help law enforcement in determining on an overweight penalty. A cost and energy consumption estimation of an acceleration sensing node is discussed. An upgraded system with low cost, low energy consumption, and self‐powered monitoring is also discussed for enabling future distributed computing and wireless application. The upgraded system might enhance integrated pavement performance and traffic monitoring.     

GYPJH2000型排水性路面机能恢复车

排水性沥青路面是一种安全、降噪功能显著的新型路面,但维持其排水机能需要相应的养护技术和专门的养护设备.GYPJH2000型排水性路面机能恢复车采用“高压水冲洗+气穴清洗+真空抽吸”的作业方式,能够冲洗清理堵塞在排水性沥青路面内部的灰尘、泥沙等杂物,并可将清理出来的杂物进行集中回收处理,恢复被堵塞路面的排水机能,使其符合使用要求.介绍GYPJH2000型排水性路面机能恢复车的结构组成、工作原理、关键技术、性能特点及施工工艺基本要求.经实际应用显示,通过该设备处理后,排水性沥青路面的排水机能可恢复到新建时期的60％以上,清洗效果显著.     

Mobile Active-Vision Traffic Surveillance System for Urban Networks

Abstract:   This article discusses the development of a mobile bus-mounted machine vision system for transit and traffic monitoring in urban corridors, as required by intelligent transportation systems. In contrast to earlier machine vision technologies used for traffic management, which rely mainly on fixed-point detection and simpler algorithms to detect certain traffic characteristics, the new proposed approach makes use of a recent trend in computer vision research; namely, the active vision paradigm. Active vision systems have mechanisms that can actively control camera parameters such as orientation, focus, zoom, and vergence in response to the requirements of the task and external stimuli. Mounting active vision systems on buses will have the advantage of providing real-time feedback of the current traffic conditions, while possessing the intelligence and visual skills that allow them to interact with a rapidly changing dynamic environment, such as moving traffic and continuously changing image background.     

Toward an Integrated Smart Sensing System and Data Interpretation Techniques for Pavement Fatigue Monitoring

Abstract: Currently, pavement instrumentation for condition monitoring is done on a localized and short‐term basis. Existing technology does not allow for continuous long‐term monitoring and network level deployment. Long‐term monitoring of mechanical loading for pavement structures could reduce maintenance costs, improve longevity, and enhance safety. In this article, on‐going research to develop and validate a smart pavement monitoring system is described. The system mainly consists of a novel self‐powered wireless sensor based on the integration of piezoelectric transduction with floating‐gate injection capable of detecting, storing, and transmitting strain history for long‐term monitoring and a novel passive temperature gauge. A technique for estimating full‐field strain distributions using measured data from a limited number of implemented sensors is also described. The ultimate purpose is to incorporate the traffic wander effect in the fatigue prediction algorithms. Preliminary results are shown and limitations are discussed.     

Pavement performance assessment using a cost‐effective wireless accelerometer system

Pavement condition monitoring is required to identify pavements in need of maintenance or rehabilitation. Early identification of reduction in pavement's structural resistance and improving the structural resistance by minor repairs can lead to significantly lower maintenance costs for transportation agencies. In this study, a cost‐effective wireless sensor that can be embedded in the road to measure the transient vibrations due to different applied loads was tested to determine its effectiveness in terms of pavement displacement measurements. Test results show that the vibration sensor, combined with the algorithms, can be embedded in new or existing pavements and used as an accurate wireless displacement sensor. The low cost of the sensor system allows the use of these sensors at high densities for monitoring the performance of an entire road network. Outputs from the developed system can be directly used to evaluate the condition and performance of pavement structure (increasing displacement over time indicating increasing pavement damage). In addition, displacement data from the system can be used to backcalculate pavement layer stiffnesses, which can be used to predict long‐term performance of the pavement structure. Reduction in pavement layer stiffness over time can be used to determine long‐term damage accumulation.     

小区电梯集中监控系统的开发

介绍了一种使用现场总线技术构建的小区电梯集中监控系统,利用微处理器的串/并行接口采集电梯信息,采用CAN总线串行通信技术,通过小区底层通信控制网络与监控中心进行数据传输.     

上海大型港区自动环境监测系统设计总体方案

上海港作为国际航运中心的重要载体,面临的环境压力日益增大,环境监测工作显得尤为重要。根据上海港区分布特点及环境监测需求,设计港区自动环境监测系统,包括港区环境监测设备及港区环境监测信息平台。通过构建涵盖空气、水质、噪声的自动在线环境监测系统,辅以部分手动检测点获取环境实时数据,经无线通信方式上传数据至港区环境监测信息平台综合分析、处理,建设布局科学、管理完善的港区环境监测网络,达到自动环境监测目标。     

三车道大断面高速公路隧道稳定性数值模拟

随着我国高等级公路的发展,三车道大断面公路隧道将成为高等级公路隧道的重要组成部分,这同时也对高速公路隧道的设计和施工提出了更高的要求.文章以杭新景高速公路设岭隧道为例,结合该隧道的监控量测,分析了围岩变形过程并针对监测数据进行了动态反馈,同时检验了施工单位根据反馈情况采取措施后的效果.最后通过Plaxis有限元软件模拟了整个隧道围岩的变形过程,取得了良好的效果.由此可见,通过有效的监控动态反馈及有限元模拟,能有效的对隧道开挖过程中的围岩变形进行预测,从而大大降低隧道施工中的风险,保证隧道的施工安全.     

RAP在排水沥青混凝土中的应用研究

采用 RAP 取代部分天然砂石,添加矿物纤维及矿粉等进行配合设计试验,评估再生沥青排水路面各项工程性质。据试验结果,添加30%RAP,工程性质可满足规范要求。故排水路面适量添加RAP,在适当的范围内满足了规范要求。     

Development of a Cost‐Effective Wireless Vibration Weigh‐In‐Motion System to Estimate Axle Weights of Trucks

Truck weight data plays an important role in weight enforcement and pavement condition assessment. This data is primarily obtained through weigh stations and Weigh‐In‐Motion (WIM) stations which are currently very expensive to install and maintain. This article presents results of the implementation of an inexpensive wireless sensor‐based vibration WIM system. The proposed wireless sensor network (WSN) consists of acceleration sensors that report pavement vibration; vehicle detection sensors that report a vehicle's arrival and departure times; and an access point (AP) that synchronizes all the sensors and records the sensor data. The article also describes a new method for speed compensation, an energy‐efficient algorithm (adaptive sampling method) to increase battery life, and a new modeling procedure to estimate gross vehicle weights. The system deployed near a conventional WIM system on I‐80W in Pinole, CA passed the accuracy standards for WIM systems and outperformed a nearby commercial WIM station, based on conventional technology.     

基于GPRS网络的金属氧化物避雷器在线监测系统设计

为了克服金属氧化物避雷器在线监测器有线传输方式存在的弊端,提出一种基于GPRS远程监测避雷器状态的新方法。利用该方法设计的监测系统主要包括现场采集部分、GPRS通信部分和远程监测中心系统管理部分。现场采集部分以TMS320F2812微处理器为核心处理器,对避雷器的阻性电流进行实时检测。现场采集结果通过GPRS发送到监测中心数据库中形成数据报表,在监测中心可以通过远程实时对避雷器状态进行监测和对历史数据进行查询分析,达到保证电力系统稳定运行的目的。     

基于89s52单片机的绝缘子检测控制系统设计

针对绝缘子试验环境的要求,设计出一套用于检测绝缘子机械强度的温度及拉力控制系统。从硬件和软件两个方面阐述了本系统的工作原理及功能,重点分析了上位机利用MCGS组态软件与单片机的通信问题;同时基于MCGS开发出一套温度和压力的监控软件。实验结果表明,对于温度的交替变化和压力的恒定维持取得了较为满意的效果。     

钢桥面铺装对移动荷载的动态响应研究

通过建立钢桥面铺装体系力学分析模型,对以一定的速度移动的车辆荷载,钢桥面铺装层的受力影响进行数值模拟。分析了铺装体系在不同车速行驶的车辆移动荷载作用下的横向拉应力、纵向拉应力、表面竖向位移、剪应力和相同车速下铺装层剪应力等受力特性。最后得出的结论可以为进一步分析桥面铺装问题提供理论参考。     

电池管理系统（DBMS）——数据中心部署中必不可少的组成部分

意外断电对数据中心带来的损失将是非常巨大的,因此,配置一套可靠的电源保护系统至关重要。本文以北美数据中心为例,阐述了投资一套能够每天监测电池内阻的电池管理系统（DBMS）,将会极大节约人工维护费用并延长电池寿命,同时可以降低服务中断和意外宕机带来的风险,为数据中心带来巨大的成本效益。     

路面不平整引起的车辆动荷载分析

针对高速公路路基不均匀沉降引起的路面不平整等工程技术问题 ,首先描述了不同形式的移动车辆荷载的数学模型 ,然后假设路面不平整为正弦函数 ,将汽车简化为两自由度振动体系 ,对由路面不平整引起的车辆附加动荷载及其影响因素进行了分析 ,为路面结构设计和车辆 -路面动力相互作用分析提供了基础性成果。     

地铁车站盖挖法竖向支承构件设计方法研究

在地铁车站盖挖法施工中,临时路面体系和中间立柱是结构竖向承载的主要构件.在我国,临时路面体系应用较少,因此没有形成相应的设计规范;对于中间立柱来说,若采用规范上的方法进行设计,计算起来将比较繁琐.文中提出的一套临时路面体系的设计方法,以及立柱设计的简化计算方法,对今后地铁车站盖挖法的设计工作有一定的参考价值.     

飞机动荷载作用下场道地基沉降

地基沉降问题是软土地基上修建跑道的关键问题,上海浦东机场对修建在软土地基上的跑道进行了长期道面沉降观测。通过对浦东机场两条跑道道面沉降观测资料的分析,提出了采用通航以来跑道横断面上10 m线测点与30 m线测点之间的差异沉降近似确定飞机动载沉降的方法,并分析了飞机动载沉降在时间及空间上的变化规律。认为动载沉降在通航初期2～3年增加较大、之后增加缓慢,动载沉降占总沉降的份额随着时间的延续不断增大,一跑道通航10年后,该份额平均约为10%左右。截止2009年4月,浦东机场一、二跑道以均匀沉降为主,差异沉降较小。     

Performance-based characterization of Arab asphalt

Asphalt binders are elasto-visco-elastic materials where temperature and rate of load application have a great influence on their behavior. They are classified as rheological materials since their stress-strain response is both time and temperature dependent. Asphalt binder consistency and hence ability to sustain and hold its fundamental cementing mechanism changes depending on temperature. In this research, the physical and rheological properties of the locally produced Arab asphalt binders and the performance requirements of the Gulf countries environmental conditions were determined. The designed experiments and the collected data clearly indicated that the locally produced asphalt binders can be used without modification in areas where the maximum pavement temperature does not exceed 64 °C. Temperature zoning indicated that more than 50% of the Gulf countries areas experience a maximum pavement temperature of 76 °C. Therefore, asphalt binder modification is required to meet Gulf countries' performance requirements.     

钢桥面沥青铺装层设计要点分析

本文根据笔者多年的工作经验,从钢桥面沥青铺装设计的技术要求、桥面沥青铺层的结构和大跨径钢桥面沥青铺装三个方面,探讨了钢桥面沥青铺装层的设计要点。