Development of a System for Collecting Loop-Detector Event Data for Individual Vehicles

2003 ◽  
Vol 1855 (1) ◽  
pp. 168-175 ◽  
Author(s):  
Xiaoping Zhang ◽  
Yinhai Wang ◽  
Nancy L. Nihan ◽  
Mark E. Hallenbeck
Keyword(s):  
Real Time ◽  
Sampling Rate ◽  
Field Application ◽  
Normal Operation ◽  
Vehicle Speed ◽  
Event Data ◽  
Loop Detectors ◽  
Loop Detector ◽  
High Sampling Rate ◽  
Loop Detection

Typical freeway inductive loop detection systems, under normal operation, aggregate individual loop-detector actuations sampled at 60 Hz into 20-s or 30-s averages of velocity, flow, and lane-occupancy measurements. While such aggregations are appropriate for serving as inputs to control system algorithms, and they save disk space for archiving loop data, a large amount of useful data regarding individual vehicles is lost. For single-loop detectors, the lost information includes individual vehicle arrival, departure, and presence times. For speed traps, the lost information also includes the calculated individual vehicle speed and length. Yet this information about individual vehicles is desirable to transportation researchers and planners. The unavailability of this information makes in-depth investigation of detector errors difficult or even impossible. A system for collecting detector event data is proposed. This system can sample loop actuations with sampling rates of 60 Hz or higher and then save, process, and present the collected event data in real time without interfering with the detector controller’s normal operation. A stand-alone Windows program was developed for performing real-time high-frequency loop event data collection. A system reliability test and field application indicate that the system can collect realtime detector event data at a high sampling rate (60 Hz or higher). Additionally, this system makes real-time loop data quality evaluation, loop malfunction identification, and loop error correction feasible.

scholarly journals Improved Dual-Loop Detection System for Collecting Real-Time Truck Data

2005 ◽  
Vol 1917 (1) ◽  
pp. 108-115 ◽  
Author(s):  
Xiaoping Zhang ◽  
Nancy L. Nihan ◽  
Yinhai Wang
Keyword(s):  
Real Time ◽  
Detection System ◽  
Normal Operation ◽  
Event Data ◽  
Loop Detectors ◽  
Real Time Traffic ◽  
System A ◽  
Loop Detection ◽  
Washington State Department ◽  
Transportation Research

The Washington State Department of Transportation (WSDOT) has a loop detection system on its Greater Seattle freeway network to provide real-time traffic data. The dual-loop detectors installed in the system are used to measure vehicle lengths and then classify each detected vehicle into one of four categories according to its length. The dual loop's capability of measuring vehicle length makes the loop detection system a potential real-time truck data source for freight movement studies because truck volume estimates by basic length category can be developed from the vehicle length measurements produced by the dual-loop detectors. However, a previous study found that the dual-loop detectors were consistently underreporting truck volumes, whereas the single-loop detectors were consistently overcounting vehicle volumes. As an extension of the previous study, the research project described here investigated possible causes of loop errors under nonforced-flow traffic conditions. A new dual-loop algorithm that can address these error causes and therefore tolerate erroneous loop actuation signals was developed to improve the performance of the WSDOT loop detection system. A quick remedy method was also recommended to address the dual-loop undercount problem without replacing any part of the existing system hardware or software. In addition, a laptop-based detector event data collection system (DEDAC) that can collect loop detector event data without interrupting a loop detection system's normal operation was developed in this research. The DEDAC system enables various kinds of transportation research and applications that could not otherwise be possible.

Intelligent Displacement Measuring System for Rock Stratum

2011 ◽  
Vol 103 ◽  
pp. 583-586
Author(s):  
Feng Ling Li ◽  
Jian Hua Rong ◽  
Yu Ping Zhang
Keyword(s):  
Civil Engineer ◽  
Real Time ◽  
Sampling Rate ◽  
Measuring System ◽  
Displacement Sensor ◽  
Rock Stratum ◽  
Baud Rate ◽  
Real Time Clock ◽  
High Sampling Rate ◽  
Displacement System

Measuring rock stratum displacement in dam grouting process is very important. A new displacement system is designed, comprising a programmable microcontroller Atmega16, a new grating capacitive displacement sensor(GCDS), DS1302 real time clock chip and announciator etc. The system has high sampling rate of 9600 baud rate and can trap the displacement equal to 0.001 millimeter in one second. Equipped with mechanical conveyance system, the system can be applied to the civil engineer. The experiment results show the instrument can measure accurately the displacement value and alarm geologic disaster in time, which can conduct continuous and accurate monitoring and provide operation decisions for dam engineers.

Torsional Vibration Detection Using High Sampling Rate and High Resolution Keyphasor Information

2013 ◽  
Author(s):  
Huageng Luo ◽  
Roengchai Chumai ◽  
Nicolas Peton ◽  
Brian Howard ◽  
Arun Menon
Keyword(s):  
Torsional Vibration ◽  
Sampling Rate ◽  
Synchronous Motor ◽  
Rotating Machinery ◽  
Normal Operation ◽  
Machinery Condition Monitoring ◽  
Vibration Detection ◽  
High Sampling ◽  
High Sampling Rate ◽  
Phase Demodulation

Torsional vibration excitation in rotating machinery can cause system reliability issues or even catastrophic failures. Torsional vibration detection and monitoring becomes an important step in rotating machinery condition monitoring, especially for those machines driven by a variable frequency drive (VFD), a pulse width modulation motor (PWM), or a synchronous motor (SM), etc. Traditionally, the torsional vibration is detected by a phase demodulation process applied to the signals generated by tooth wheels or optical encoders. This demodulation based method has a few unfavorable issues: the installation of the tooth wheels needs to interrupt the machinery normal operation; the installation of the optical barcode is relatively easier, however, it suffers from short term survivability in harsh industrial environments. The geometric irregularities in the tooth wheel and the end discontinuity in the optical encoder will sometimes introduce overwhelming contaminations from shaft order response and its harmonics. In addition, the Hilbert Transform based phase demodulation technique has inevitable errors caused by the edge effect in FFT and IFFT analyses. Fortunately, in many industrial rotating machinery applications, the torsional vibration resonant frequency is usually low and the Keyphasor® and/or encoder for speed monitoring is readily available. Thus, it is feasible to use existing hardware for torsional vibration detection. In this paper, we present a signal processing approach which used the Keyphasor/encoder data digitized by a high sampling rate and high digitization resolution analog-to-digital (A/D) convertor to evaluate the torsional vibration directly. A wavelet decomposition (WD) based method was used to separate the torsional vibration from the shaft speed, so that the time history of the torsional vibrations can be extracted without significant distortions. The developed approach was then validated through a synchronous motor fan drive and an industrial power generation system. Detailed results are presented and discussed in this paper.

Real Time Statistical Leak Detection on the RRP Crude Oil Network, Holland

2002 ◽  
Author(s):  
Joep Hoeijmakers ◽  
John Lewis
Keyword(s):  
Crude Oil ◽  
Real Time ◽  
Detection System ◽  
Leak Detection ◽  
Field Application ◽  
Normal Operation ◽  
False Alarms ◽  
Pipeline Network ◽  
Oil Pipeline ◽  
Detection Systems

Prior to the year 2000, the RRP crude oil pipeline network in Holland and Germany was monitored using a dynamic leak detection system based on a dynamic model. The system produced some false alarms during normal operation; prompting RRP to investigate what advances had been made in the leak detection field before committing to upgrade the existing system for Y2K compliance. RRP studied the available leak detection systems and decided to install a statistics-based system. This paper examines the field application of the statistics based leak detection system on the three crude oil pipelines operated by RRP. They are the 177 km Dutch line, the 103 km South line, and the 86 km North line. The results of actual field leak trials are reported. Leak detection systems should maintain high sensitivity with the minimum of false alarms over the long term; thus this paper also outlines the performance of the statistical leak detection system over the last year from the User’s perspective. The leak detection experiences documented on this crude oil pipeline network demonstrate that it is possible to have a reliable real-time leak detection system with minimal maintenance costs and without the costs and inconvenience of false alarms.

A Multi-Rate Implementation of Auditory Filter Bank

2013 ◽  
Vol 373-375 ◽  
pp. 579-582
Author(s):  
Jin Lun Chen
Keyword(s):  
Signal Processing ◽  
Real Time ◽  
Filter Bank ◽  
Sampling Rate ◽  
Audio Signal ◽  
Audio Signal Processing ◽  
Auditory Model ◽  
Auditory Filter ◽  
Centre Frequency ◽  
High Sampling Rate

The auditory filter-bank is the key component of auditory model, and its implementation involves a lot of computations. The time spent by an auditory filter-bank to finish its work has a significant effect on the real-time implementation of auditory model-based audio signal processing systems. In this paper, a multi-rate implementation of auditory filter bank is presented. Through using low sampling rate for the filters with low centre frequency, and using high sampling rate for the filters with high centre frequency, we can greatly reduce the computation requirement.

Methodology for Full Waveform Near Real-Time Automatic Detection and Localization of Microseismic Events Using High (8 kHz) Sampling Rate Records in Mines: Application to the Garpenberg Mine (Sweden)

2019 ◽  
Vol 91 (1) ◽  
pp. 399-414 ◽  
Author(s):  
Kadek Hendrawan Palgunadi ◽  
Natalia Poiata ◽  
Jannes Kinscher ◽  
Pascal Bernard ◽  
Francesca De Santis ◽  
...  
Keyword(s):  
Real Time ◽  
Sampling Rate ◽  
Seismic Network ◽  
Event Extraction ◽  
Noise Sources ◽  
Full Waveform ◽  
High Sampling ◽  
High Sampling Rate ◽  
Wide Range ◽  
Microseismic Events

Abstract Recent studies have demonstrated the success of automatic full-waveform detection and location methods in analyzing and monitoring natural and induced seismicity. These approaches have been shown to provide a significant improvement in events detectability, increasing the significance of statistical analysis that permits to identify small changes of seismicity rates in space and time. Although currently nontrivial and by far nonstandard, application of such methods to seismic monitoring of active mines could significantly improve forecasting of potential destructive rockburst events. The main challenges of such applications are related to the presence of a wide range of seismic noise sources that have to do with mining activity and a high sampling rate of recorded data (several kHz), posing problems for real-time data transfer and processing. In this study, we propose an adapted full-waveform-based automatic method for the detection and location of microseismic events that makes use of continuous seismic records from an in-mine seismic network and can be adjusted to a near-real-time monitoring scheme. The method consists of two steps: (1) event extraction and amplitude ratio-based preliminary location and (2) event relocation using a coherency-based backprojection approach. The event extraction, based on multiband signal characterization implemented in the first step, allows us to overcome the challenge of high sampling rate data (8 kHz), reducing the overall volume of transferred data and providing an energy-based signal classification scheme. This allows us to remove a significant number of machinery noise sources. The technique is developed and tested on the case study of the Garpenberg mine (Sweden) monitored by a local seismic network that is maintained by Ineris. We demonstrate the improvement in event detection capacity by a factor of 50, compared with the standard triggered-based monitoring schemes. This increased number of detected microseismic events permits us to investigate the migration pattern of induced microseismicity that is generated in response to production blast.

Sensor Performance in Measuring Vehicle Length

2013 ◽  
Vol 2339 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Erik Minge ◽  
Scott Petersen
Keyword(s):  
Field Testing ◽  
The United States ◽  
Vehicle Classification ◽  
Vehicle Speed ◽  
Detector Performance ◽  
Sensor Performance ◽  
Loop Detectors ◽  
Small Magnetic Field ◽  
Loop Detector ◽  
Detection Technologies

Although most vehicle classification conducted in the United States is axle based, some applications could be supplemented or replaced by length-based data. Common length-based methods, including loop detectors and several types of nonloop sensors (both side-fire and in-road sensors), are more widespread and can be less expensive. The most frequently deployed data collection method is by loop detector, and most dual-loop installations can report vehicle length. This paper examines field and laboratory tests of loop detectors and nonloop sensors for their performance in determining vehicle length and vehicle speed. Field testing was conducted at four locations in Minnesota and South Dakota. Ten commercially available sensors were evaluated. The testing results indicated that across a variety of detection technologies, the loop detectors and nonloop sensors generally reported comparable length and speed data. The research also examined various loop configurations and found that 6- x 6-ft loops performed similarly to 6- x 8-ft loops, although 6- x 6-ft quadrupole loops performed poorly for vehicles with high beds because of the loops’ relatively small magnetic field. Loop detector performance was found not to degrade with the variety of lead-in wire lengths that were tested. Laboratory testing conducted with a loop simulator confirmed the field testing and found that loop detector data are generally repeatable.

scholarly journals An Improved Multipath Mitigation Method and Its Application in Real-Time Bridge Deformation Monitoring

2021 ◽  
Vol 13 (12) ◽  
pp. 2259
Author(s):  
Ruicheng Zhang ◽  
Chengfa Gao ◽  
Qing Zhao ◽  
Zihan Peng ◽  
Rui Shang
Keyword(s):  
Real Time ◽  
Sampling Rate ◽  
Threshold Value ◽  
Deformation Monitoring ◽  
Success Rates ◽  
Multipath Mitigation ◽  
Mode Decomposition ◽  
Observation Noise ◽  
Original Observation ◽  
Better Than

A multipath is a major error source in bridge deformation monitoring and the key to achieving millimeter-level monitoring. Although the traditional MHM (multipath hemispherical map) algorithm can be applied to multipath mitigation in real-time scenarios, accuracy needs to be further improved due to the influence of observation noise and the multipath differences between different satellites. Aiming at the insufficiency of MHM in dealing with the adverse impact of observation noise, we proposed the MHM_V model, based on Variational Mode Decomposition (VMD) and the MHM algorithm. Utilizing the VMD algorithm to extract the multipath from single-difference (SD) residuals, and according to the principle of the closest elevation and azimuth, the original observation of carrier phase in the few days following the implementation are corrected to mitigate the influence of the multipath. The MHM_V model proposed in this paper is verified and compared with the traditional MHM algorithm by using the observed data of the Forth Road Bridge with a seven day and 10 s sampling rate. The results show that the correlation coefficient of the multipath on two adjacent days was increased by about 10% after residual denoising with the VMD algorithm; the standard deviations of residual error in the L1/L2 frequencies were improved by 37.8% and 40.7%, respectively, which were better than the scores of 26.1% and 31.0% for the MHM algorithm. Taking a ratio equal to three as the threshold value, the fixed success rates of ambiguity were 88.0% without multipath mitigation and 99.4% after mitigating the multipath with MHM_V. The MHM_V algorithm can effectively improve the success rate, reliability, and convergence rate of ambiguity resolution in a bridge multipath environment and perform better than the MHM algorithm.

scholarly journals Nanozymes for Environmental Pollutant Monitoring and Remediation

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 408
Author(s):  
Elicia L. S. Wong ◽  
Khuong Q. Vuong ◽  
Edith Chow
Keyword(s):  
Real Time ◽  
Organic Pollutants ◽  
Architectural Design ◽  
Electrochemical Techniques ◽  
Environmental Pollutant ◽  
Field Application ◽  
Optical Methods ◽  
Enzyme Mimicking ◽  
Active Metal ◽  
Recent Developments

Nanozymes are advanced nanomaterials which mimic natural enzymes by exhibiting enzyme-like properties. As nanozymes offer better structural stability over their respective natural enzymes, they are ideal candidates for real-time and/or remote environmental pollutant monitoring and remediation. In this review, we classify nanozymes into four types depending on their enzyme-mimicking behaviour (active metal centre mimic, functional mimic, nanocomposite or 3D structural mimic) and offer mechanistic insights into the nature of their catalytic activity. Following this, we discuss the current environmental translation of nanozymes into a powerful sensing or remediation tool through inventive nano-architectural design of nanozymes and their transduction methodologies. Here, we focus on recent developments in nanozymes for the detection of heavy metal ions, pesticides and other organic pollutants, emphasising optical methods and a few electrochemical techniques. Strategies to remediate persistent organic pollutants such as pesticides, phenols, antibiotics and textile dyes are included. We conclude with a discussion on the practical deployment of these nanozymes in terms of their effectiveness, reusability, real-time in-field application, commercial production and regulatory considerations.

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