SmartDATA Lab Publications
2012
23.
Chang Liu, Joel Harley, Nicholas O'Donoughue, Yujie Ying, Martin H Altschul, James H Jr Garrett, José M F Moura, Irving J Oppenheim, Lucio Soibelman
Ultrasonic monitoring of a pipe under operating conditions Proceedings Article
In: Tomizuka, Masayoshi; Yun, Chung-Bang; Lynch, Jerome P (Ed.): Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2012, pp. 83450B, International Society for Optics and Photonics, San Diego, CA, 2012.
@inproceedings{Liu2012-rx,
title = {Ultrasonic monitoring of a pipe under operating conditions},
author = {Chang Liu and Joel Harley and Nicholas O'Donoughue and Yujie Ying and Martin H Altschul and James H Jr Garrett and José M F Moura and Irving J Oppenheim and Lucio Soibelman},
editor = {Masayoshi Tomizuka and Chung-Bang Yun and Jerome P Lynch},
url = {http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=1313889},
doi = {10.1117/12.915040},
year = {2012},
date = {2012-04-01},
booktitle = {Sensors and Smart Structures Technologies for Civil, Mechanical,
and Aerospace Systems 2012},
volume = {8345},
pages = {83450B},
publisher = {International Society for Optics and Photonics},
address = {San Diego, CA},
abstract = {The paper presents experimental results of applying an ultrasonic
monitoring system to a real-world operating hot-water supply
system. The purpose of these experiments is to investigate the
feasibility of continuous ultrasonic damage detection on pipes
with permanently mounted piezoelectric transducers under
environmental and operational variations. Ultrasonic guided wave
is shown to be an efficient damage detector in laboratory
experiments. However, environmental and operational variations
produce dramatic changes in those signals, and therefore a useful
signal processing approach must distinguish change caused by a
scatterer from change caused by ongoing variations. We study
pressurized pipe segments (10-in diameter) in a working hot-water
supply system that experiences ongoing variations in pressure,
temperature, and flow rate; the system is located in an
environment that is mechanically and electrically noisy. We
conduct pitch-catch tests, with a duration of 10 ms, between
transducers located roughly 12 diameters apart. We applied
different signal processing techniques to the collected data in
order to investigate the ongoing environmental and operational
variations and the stationarity of the signal. We present our
analysis of these signals and preliminary detection results.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The paper presents experimental results of applying an ultrasonic
monitoring system to a real-world operating hot-water supply
system. The purpose of these experiments is to investigate the
feasibility of continuous ultrasonic damage detection on pipes
with permanently mounted piezoelectric transducers under
environmental and operational variations. Ultrasonic guided wave
is shown to be an efficient damage detector in laboratory
experiments. However, environmental and operational variations
produce dramatic changes in those signals, and therefore a useful
signal processing approach must distinguish change caused by a
scatterer from change caused by ongoing variations. We study
pressurized pipe segments (10-in diameter) in a working hot-water
supply system that experiences ongoing variations in pressure,
temperature, and flow rate; the system is located in an
environment that is mechanically and electrically noisy. We
conduct pitch-catch tests, with a duration of 10 ms, between
transducers located roughly 12 diameters apart. We applied
different signal processing techniques to the collected data in
order to investigate the ongoing environmental and operational
variations and the stationarity of the signal. We present our
analysis of these signals and preliminary detection results.
monitoring system to a real-world operating hot-water supply
system. The purpose of these experiments is to investigate the
feasibility of continuous ultrasonic damage detection on pipes
with permanently mounted piezoelectric transducers under
environmental and operational variations. Ultrasonic guided wave
is shown to be an efficient damage detector in laboratory
experiments. However, environmental and operational variations
produce dramatic changes in those signals, and therefore a useful
signal processing approach must distinguish change caused by a
scatterer from change caused by ongoing variations. We study
pressurized pipe segments (10-in diameter) in a working hot-water
supply system that experiences ongoing variations in pressure,
temperature, and flow rate; the system is located in an
environment that is mechanically and electrically noisy. We
conduct pitch-catch tests, with a duration of 10 ms, between
transducers located roughly 12 diameters apart. We applied
different signal processing techniques to the collected data in
order to investigate the ongoing environmental and operational
variations and the stationarity of the signal. We present our
analysis of these signals and preliminary detection results.
2011
22.
J B Harley, J M F Moura
Guided wave temperature compensation with the scale-invariant correlation coefficient Proceedings Article
In: 2011 IEEE International Ultrasonics Symposium, pp. 1068–1071, Orlando, FL, 2011.
@inproceedings{Harley2011-ms,
title = {Guided wave temperature compensation with the scale-invariant
correlation coefficient},
author = {J B Harley and J M F Moura},
url = {http://dx.doi.org/10.1109/ULTSYM.2011.0218},
doi = {10.1109/ULTSYM.2011.0218},
year = {2011},
date = {2011-10-01},
booktitle = {2011 IEEE International Ultrasonics Symposium},
pages = {1068–1071},
address = {Orlando, FL},
abstract = {One of the greatest challenges toward developing guided wave
structural health monitoring technology is the necessity to
distinguish benign effects from those caused by damage.
Variations in temperature, one of the most prominent benign
effects, are known to stretch or scale ultrasonic signals in
time. Several techniques have been proposed to compensate for the
effects of temperature, but they tend to be computationally
expensive, require locally convex conditions, or lack robustness
to modeling error. In this paper, we present a new technique,
based on the Mellin and scale transforms, which takes advantage
of available fast algorithms for computing and compensating
stretch-based operations. Using experimental data, we show our
technique to be accurate, robust, and algorithmically faster than
other existing techniques.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
One of the greatest challenges toward developing guided wave
structural health monitoring technology is the necessity to
distinguish benign effects from those caused by damage.
Variations in temperature, one of the most prominent benign
effects, are known to stretch or scale ultrasonic signals in
time. Several techniques have been proposed to compensate for the
effects of temperature, but they tend to be computationally
expensive, require locally convex conditions, or lack robustness
to modeling error. In this paper, we present a new technique,
based on the Mellin and scale transforms, which takes advantage
of available fast algorithms for computing and compensating
stretch-based operations. Using experimental data, we show our
technique to be accurate, robust, and algorithmically faster than
other existing techniques.
structural health monitoring technology is the necessity to
distinguish benign effects from those caused by damage.
Variations in temperature, one of the most prominent benign
effects, are known to stretch or scale ultrasonic signals in
time. Several techniques have been proposed to compensate for the
effects of temperature, but they tend to be computationally
expensive, require locally convex conditions, or lack robustness
to modeling error. In this paper, we present a new technique,
based on the Mellin and scale transforms, which takes advantage
of available fast algorithms for computing and compensating
stretch-based operations. Using experimental data, we show our
technique to be accurate, robust, and algorithmically faster than
other existing techniques.
21.
Yujie Ying, James H Garrett, Joel B Harley, M F Moura, Nicholas O'Donoughue, Irving J Oppenheim
Machine Learning for Pipeline Monitoring under Environmental and Operational Variations Proceedings Article
In: Proc. of the International Workshop on Structural Health Monitoring, Stanford, CA, 2011.
@inproceedings{Ying2011-he,
title = {Machine Learning for Pipeline Monitoring under Environmental and
Operational Variations},
author = {Yujie Ying and James H Garrett and Joel B Harley and M F Moura and Nicholas O'Donoughue and Irving J Oppenheim},
year = {2011},
date = {2011-09-01},
booktitle = {Proc. of the International Workshop on Structural Health
Monitoring},
address = {Stanford, CA},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
20.
Joel B Harley, José M F Moura, Inqueries To
An efficient temperature compensation technique for guided wave ultrasonic inspection Journal Article
In: pp. 9, 2011.
@article{Harley2011-sg,
title = {An efficient temperature compensation technique for guided wave
ultrasonic inspection},
author = {Joel B Harley and José M F Moura and Inqueries To},
url = {https://www.researchgate.net/profile/Joel-Harley/publication/259287297_An_efficient_temperature_compensation_technique_for_guided_wave_ultrasonic_inspection/links/5563610208ae86c06b695459/An-efficient-temperature-compensation-technique-for-guided-wave-ultrasonic-inspection.pdf},
year = {2011},
date = {2011-09-01},
pages = {9},
abstract = {One challenge in the development of structural health monitoring
technology is the necessity to distinguish benign effects from
those caused by damage. For ultrasonic guided waves systems, this
is a problem of particular importance. Guided waves create
complex, multi-modal, and dispersive wave fields which reflect off
specimen boundaries as well as damage. Direct time-domain
comparisons with a known baseline can be used to overcome these
complexities, but fail to discriminate damage from benign
environmental effects. Although many environmental changes affect
guided waves, variations in temperature are often the most
dominant. This paper proposes a computationally efficient
temperature compensation technique based on the scale-invariant
correlation coefficient. Using experimental measurements, we
compare the performance of the scale-invariant correlation
coefficient with two other compensation strategies: the local peak
coherence and optimal signal stretch methods. We demonstrate the
scale-invariant correlation coefficient to be robust, effective,
and computational efficient.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
One challenge in the development of structural health monitoring
technology is the necessity to distinguish benign effects from
those caused by damage. For ultrasonic guided waves systems, this
is a problem of particular importance. Guided waves create
complex, multi-modal, and dispersive wave fields which reflect off
specimen boundaries as well as damage. Direct time-domain
comparisons with a known baseline can be used to overcome these
complexities, but fail to discriminate damage from benign
environmental effects. Although many environmental changes affect
guided waves, variations in temperature are often the most
dominant. This paper proposes a computationally efficient
temperature compensation technique based on the scale-invariant
correlation coefficient. Using experimental measurements, we
compare the performance of the scale-invariant correlation
coefficient with two other compensation strategies: the local peak
coherence and optimal signal stretch methods. We demonstrate the
scale-invariant correlation coefficient to be robust, effective,
and computational efficient.
technology is the necessity to distinguish benign effects from
those caused by damage. For ultrasonic guided waves systems, this
is a problem of particular importance. Guided waves create
complex, multi-modal, and dispersive wave fields which reflect off
specimen boundaries as well as damage. Direct time-domain
comparisons with a known baseline can be used to overcome these
complexities, but fail to discriminate damage from benign
environmental effects. Although many environmental changes affect
guided waves, variations in temperature are often the most
dominant. This paper proposes a computationally efficient
temperature compensation technique based on the scale-invariant
correlation coefficient. Using experimental measurements, we
compare the performance of the scale-invariant correlation
coefficient with two other compensation strategies: the local peak
coherence and optimal signal stretch methods. We demonstrate the
scale-invariant correlation coefficient to be robust, effective,
and computational efficient.
19.
Yujie Ying, Joel Harley, James H Jr Garrett, Yuanwei Jin, Irving J Oppenheim, Jun Shi, Lucio Soibelman
Applications of Machine Learning in Pipeline Monitoring Proceedings Article
In: Computing in Civil Engineering (2011), pp. 242–249, American Society of Civil Engineers, Reston, VA, 2011.
@inproceedings{Ying2011-ka,
title = {Applications of Machine Learning in Pipeline Monitoring},
author = {Yujie Ying and Joel Harley and James H Jr Garrett and Yuanwei Jin and Irving J Oppenheim and Jun Shi and Lucio Soibelman},
url = {http://ascelibrary.org/doi/10.1061/41182%28416%2930},
doi = {10.1061/41182(416)30},
year = {2011},
date = {2011-06-01},
booktitle = {Computing in Civil Engineering (2011)},
pages = {242–249},
publisher = {American Society of Civil Engineers},
address = {Reston, VA},
abstract = {In the field of structural health monitoring, researchers focus
on the design of systems and techniques capable of detecting
damage in structures. However, most traditional detection methods
fail under environmental and operational variations that tend to
distort the signals and masquerade as damage. In this paper, we
investigate the applications of machine learning techniques to
developing a damage detection system robust to changes in the
internal air pressure of a pipe. From each of the 240
experimental datasets, we extract 167 features and implement
three classification algorithms for detecting damage: adaptive
boosting, support vector machines, and a method combining the
two. The performances of the three classifiers are evaluated over
30 detection trials with different combinations of training and
testing data, resulting in the average accuracies of 87.7%,
92.5% and 93.5%, respectively. The combined method is a
promising classifier for damage detection. Through feature
selection, we also demonstrate the effectiveness of features
related to the curve length, the shift‐invariant correlation
coefficient and the peak amplitude of the signal.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
In the field of structural health monitoring, researchers focus
on the design of systems and techniques capable of detecting
damage in structures. However, most traditional detection methods
fail under environmental and operational variations that tend to
distort the signals and masquerade as damage. In this paper, we
investigate the applications of machine learning techniques to
developing a damage detection system robust to changes in the
internal air pressure of a pipe. From each of the 240
experimental datasets, we extract 167 features and implement
three classification algorithms for detecting damage: adaptive
boosting, support vector machines, and a method combining the
two. The performances of the three classifiers are evaluated over
30 detection trials with different combinations of training and
testing data, resulting in the average accuracies of 87.7%,
92.5% and 93.5%, respectively. The combined method is a
promising classifier for damage detection. Through feature
selection, we also demonstrate the effectiveness of features
related to the curve length, the shift‐invariant correlation
coefficient and the peak amplitude of the signal.
on the design of systems and techniques capable of detecting
damage in structures. However, most traditional detection methods
fail under environmental and operational variations that tend to
distort the signals and masquerade as damage. In this paper, we
investigate the applications of machine learning techniques to
developing a damage detection system robust to changes in the
internal air pressure of a pipe. From each of the 240
experimental datasets, we extract 167 features and implement
three classification algorithms for detecting damage: adaptive
boosting, support vector machines, and a method combining the
two. The performances of the three classifiers are evaluated over
30 detection trials with different combinations of training and
testing data, resulting in the average accuracies of 87.7%,
92.5% and 93.5%, respectively. The combined method is a
promising classifier for damage detection. Through feature
selection, we also demonstrate the effectiveness of features
related to the curve length, the shift‐invariant correlation
coefficient and the peak amplitude of the signal.
18.
N O'Donoughue, J Harley, J M F Moura
Detection of targets embedded in multipath clutter with Time Reversal Proceedings Article
In: 2011 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), pp. 3868–3871, Ieee, Prague, 2011.
@inproceedings{ODonoughue2011-pa,
title = {Detection of targets embedded in multipath clutter with Time
Reversal},
author = {N O'Donoughue and J Harley and J M F Moura},
url = {http://dx.doi.org/10.1109/ICASSP.2011.5947196},
doi = {10.1109/ICASSP.2011.5947196},
year = {2011},
date = {2011-05-01},
booktitle = {2011 IEEE International Conference on Acoustics, Speech and
Signal Processing (ICASSP)},
pages = {3868–3871},
publisher = {Ieee},
address = {Prague},
abstract = {Detection of targets in complex environments is of importance in
both radar and sonar applications. Recent work has shown that the
use of Time Reversal (TR) techniques improves the performance of
systems operating in deterministic channels with a significant
multipath return. This paper extends those results to stationary
random channels with significant multipath. We develop a TR-based
approach and derive the Likelihood Ratio Test (LRT) for this
approach. We compare this TR-LRT to an LRT derived through a
“water filling” approach. We derive theoretical performance
curves for the water filling LRT, and evaluate both the water
filling and TR detectors with Monte Carlo simulations. For the
scenarios tested, we show that TR achieves an SNR gain of 1–2dB
over the water filling detector.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Detection of targets in complex environments is of importance in
both radar and sonar applications. Recent work has shown that the
use of Time Reversal (TR) techniques improves the performance of
systems operating in deterministic channels with a significant
multipath return. This paper extends those results to stationary
random channels with significant multipath. We develop a TR-based
approach and derive the Likelihood Ratio Test (LRT) for this
approach. We compare this TR-LRT to an LRT derived through a
“water filling” approach. We derive theoretical performance
curves for the water filling LRT, and evaluate both the water
filling and TR detectors with Monte Carlo simulations. For the
scenarios tested, we show that TR achieves an SNR gain of 1–2dB
over the water filling detector.
both radar and sonar applications. Recent work has shown that the
use of Time Reversal (TR) techniques improves the performance of
systems operating in deterministic channels with a significant
multipath return. This paper extends those results to stationary
random channels with significant multipath. We develop a TR-based
approach and derive the Likelihood Ratio Test (LRT) for this
approach. We compare this TR-LRT to an LRT derived through a
“water filling” approach. We derive theoretical performance
curves for the water filling LRT, and evaluate both the water
filling and TR detectors with Monte Carlo simulations. For the
scenarios tested, we show that TR achieves an SNR gain of 1–2dB
over the water filling detector.
17.
Nicholas A O’Donoughue, Joel Harley, José M F Moura, Jun Shi
Ultrasonic defect localization in pipes using time reversal Journal Article
In: The Journal of the Acoustical Society of America, vol. 129, no. 4, pp. 2532–2532, 2011.
@article{ODonoughue2011-we,
title = {Ultrasonic defect localization in pipes using time reversal},
author = {Nicholas A O’Donoughue and Joel Harley and José M F Moura and Jun Shi},
url = {http://asa.scitation.org/doi/10.1121/1.3588390},
doi = {10.1121/1.3588390},
year = {2011},
date = {2011-04-01},
journal = {The Journal of the Acoustical Society of America},
volume = {129},
number = {4},
pages = {2532–2532},
publisher = {Acoustical Society of America (ASA)},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2010
16.
Nicholas O'Donoughue, Joel Harley, José M F Moura
Time reversal beamforming of guided waves in pipes with a single defect Proceedings Article
In: 2010 Conference Record of the Forty Fourth Asilomar Conference on Signals, Systems and Computers, pp. 1786–1790, IEEE, Pacific Grove, CA, 2010.
@inproceedings{O-Donoughue2010-iw,
title = {Time reversal beamforming of guided waves in pipes with a single
defect},
author = {Nicholas O'Donoughue and Joel Harley and José M F Moura},
url = {http://dx.doi.org/10.1109/ACSSC.2010.5757849},
doi = {10.1109/ACSSC.2010.5757849},
year = {2010},
date = {2010-11-01},
booktitle = {2010 Conference Record of the Forty Fourth Asilomar Conference on
Signals, Systems and Computers},
pages = {1786–1790},
publisher = {IEEE},
address = {Pacific Grove, CA},
abstract = {Structural health monitoring of buried pipelines is an important
application for aging infrastructures. Ultrasonic guided wave
inspection is an attractive tool, due to the long propagation of
guided waves in the wall of a hollow cylinder. However, guided
waves present a unique environment with heavily multi-modal
signal propagation and complex dispersion (frequency-dependent
propagation speeds). In order to alleviate these challenges,
conventional techniques rely on high-voltage excitation with
complex transducer arrays, but these systems are not conducive to
a monitoring solution. Instead, they require periodic excavation
and testing. In prior work, we have shown that Time Reversal
allows for reliable detection with relatively simple antenna
arrays that can be operated in low-power. This paper focuses on
localization of these defects. We utilize a beamforming approach
that makes use of theoretical dispersion curves to generate fault
images. We show through simulations that Time Reversal
Beamforming achieves high-resolution localization of a fault in
the presence of strong dispersion and heavily multi-modal
propagation.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Structural health monitoring of buried pipelines is an important
application for aging infrastructures. Ultrasonic guided wave
inspection is an attractive tool, due to the long propagation of
guided waves in the wall of a hollow cylinder. However, guided
waves present a unique environment with heavily multi-modal
signal propagation and complex dispersion (frequency-dependent
propagation speeds). In order to alleviate these challenges,
conventional techniques rely on high-voltage excitation with
complex transducer arrays, but these systems are not conducive to
a monitoring solution. Instead, they require periodic excavation
and testing. In prior work, we have shown that Time Reversal
allows for reliable detection with relatively simple antenna
arrays that can be operated in low-power. This paper focuses on
localization of these defects. We utilize a beamforming approach
that makes use of theoretical dispersion curves to generate fault
images. We show through simulations that Time Reversal
Beamforming achieves high-resolution localization of a fault in
the presence of strong dispersion and heavily multi-modal
propagation.
application for aging infrastructures. Ultrasonic guided wave
inspection is an attractive tool, due to the long propagation of
guided waves in the wall of a hollow cylinder. However, guided
waves present a unique environment with heavily multi-modal
signal propagation and complex dispersion (frequency-dependent
propagation speeds). In order to alleviate these challenges,
conventional techniques rely on high-voltage excitation with
complex transducer arrays, but these systems are not conducive to
a monitoring solution. Instead, they require periodic excavation
and testing. In prior work, we have shown that Time Reversal
allows for reliable detection with relatively simple antenna
arrays that can be operated in low-power. This paper focuses on
localization of these defects. We utilize a beamforming approach
that makes use of theoretical dispersion curves to generate fault
images. We show through simulations that Time Reversal
Beamforming achieves high-resolution localization of a fault in
the presence of strong dispersion and heavily multi-modal
propagation.
15.
Yujie Ying, Joel Harley, James H Jr Garrett, Yuanwei Jin, José M F Moura, Nicholas O'Donoughue, Irving J Oppenheim, Lucio Soibelman
Time reversal for damage detection in pipes Proceedings Article
In: Tomizuka, Masayoshi (Ed.): Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010, pp. 76473S, International Society for Optics and Photonics, San Diego, CA, 2010.
@inproceedings{Ying2010-ya,
title = {Time reversal for damage detection in pipes},
author = {Yujie Ying and Joel Harley and James H Jr Garrett and Yuanwei Jin and José M F Moura and Nicholas O'Donoughue and Irving J Oppenheim and Lucio Soibelman},
editor = {Masayoshi Tomizuka},
url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/7647/1/Time-reversal-for-damage-detection-in-pipes/10.1117/12.847799.full},
doi = {10.1117/12.847799},
year = {2010},
date = {2010-04-01},
booktitle = {Sensors and Smart Structures Technologies for Civil, Mechanical,
and Aerospace Systems 2010},
volume = {7647},
pages = {76473S},
publisher = {International Society for Optics and Photonics},
address = {San Diego, CA},
abstract = {Monitoring the structural integrity of vast natural gas pipeline
networks requires continuous and economical inspection
technology. Current approaches for inspecting buried pipelines
require periodic excavation of sections of pipe to assess only a
couple of hundred meters at a time. These inspection systems for
pipelines are temporary and expensive. We propose to use
guided-wave ultrasonics with Time Reversal techniques to develop
an active sensing and continuous monitoring system. Pipe
environments are complex due to the presence of multiple modes
and high dispersion. These are treated as adverse effects by most
conventional ultrasonic techniques. However, Time Reversal takes
advantage of the multi-modal and dispersive behaviors to improve
the spatial and temporal wave focusing. In this paper, Time
Reversal process is mathematically described and experimentally
demonstrated through six laboratory experiments, providing
comprehensive and promising results on guided wave focusing in a
pipe with/without welded joint, with/without internal pressure,
and detection of three defects: lateral, longitudinal and
corrosion-like. The experimental results show that Time Reversal
can effectively compensate for multiple modes and dispersion in
pipes, resulting in an enhanced signal-to-noise ratio and
effective damage detection ability. As a consequence, Time
Reversal shows benefits in long-distance and lowpower pipeline
monitoring, as well as potential for applications in other
infrastructures.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Monitoring the structural integrity of vast natural gas pipeline
networks requires continuous and economical inspection
technology. Current approaches for inspecting buried pipelines
require periodic excavation of sections of pipe to assess only a
couple of hundred meters at a time. These inspection systems for
pipelines are temporary and expensive. We propose to use
guided-wave ultrasonics with Time Reversal techniques to develop
an active sensing and continuous monitoring system. Pipe
environments are complex due to the presence of multiple modes
and high dispersion. These are treated as adverse effects by most
conventional ultrasonic techniques. However, Time Reversal takes
advantage of the multi-modal and dispersive behaviors to improve
the spatial and temporal wave focusing. In this paper, Time
Reversal process is mathematically described and experimentally
demonstrated through six laboratory experiments, providing
comprehensive and promising results on guided wave focusing in a
pipe with/without welded joint, with/without internal pressure,
and detection of three defects: lateral, longitudinal and
corrosion-like. The experimental results show that Time Reversal
can effectively compensate for multiple modes and dispersion in
pipes, resulting in an enhanced signal-to-noise ratio and
effective damage detection ability. As a consequence, Time
Reversal shows benefits in long-distance and lowpower pipeline
monitoring, as well as potential for applications in other
infrastructures.
networks requires continuous and economical inspection
technology. Current approaches for inspecting buried pipelines
require periodic excavation of sections of pipe to assess only a
couple of hundred meters at a time. These inspection systems for
pipelines are temporary and expensive. We propose to use
guided-wave ultrasonics with Time Reversal techniques to develop
an active sensing and continuous monitoring system. Pipe
environments are complex due to the presence of multiple modes
and high dispersion. These are treated as adverse effects by most
conventional ultrasonic techniques. However, Time Reversal takes
advantage of the multi-modal and dispersive behaviors to improve
the spatial and temporal wave focusing. In this paper, Time
Reversal process is mathematically described and experimentally
demonstrated through six laboratory experiments, providing
comprehensive and promising results on guided wave focusing in a
pipe with/without welded joint, with/without internal pressure,
and detection of three defects: lateral, longitudinal and
corrosion-like. The experimental results show that Time Reversal
can effectively compensate for multiple modes and dispersion in
pipes, resulting in an enhanced signal-to-noise ratio and
effective damage detection ability. As a consequence, Time
Reversal shows benefits in long-distance and lowpower pipeline
monitoring, as well as potential for applications in other
infrastructures.
14.
Yujie Ying, Lucio Soibelman, Joel Harley, Nicholas O'Donoughue, James H Garrett, Yuanwei Jin, José M F Moura, Irving J Oppenheim
A data mining framework for pipeline monitoring using time reversal Proceedings Article
In: Proc. of SIAM Conference on Data Mining, SIAM, Columbus, Ohio, 2010.
@inproceedings{Ying2010-sm,
title = {A data mining framework for pipeline monitoring using time
reversal},
author = {Yujie Ying and Lucio Soibelman and Joel Harley and Nicholas O'Donoughue and James H Garrett and Yuanwei Jin and José M F Moura and Irving J Oppenheim},
year = {2010},
date = {2010-04-01},
booktitle = {Proc. of SIAM Conference on Data Mining},
publisher = {SIAM},
address = {Columbus, Ohio},
abstract = {This paper presents a data mining framework under development
based on Time Reversal for continuous monitoring of natural gas
pipelines. Our goal is to extract damage information from complex
guided wave patterns in pipes. We first review Time Reversal
methods, and discuss their effectiveness and limitation for
defect detection. Then, we describe our experimental results with
Time Reversal change detection which show that it is able to
detect small defects through its focusing effect. However, Time
Reversal is sensitive to changing environmental and operational
conditions, which may increase the false alarm rate. To reduce
the number of false positives, we propose a data mining framework
that integrates Time Reversal with data mining tools. The data
mining framework consists of three modules: defect detection,
defect localization, and defect classification. We explore the
potential use of Time Reversal in each work module. This paper
highlights these tasks and provides a clear work flow to further
our pipeline monitoring research.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper presents a data mining framework under development
based on Time Reversal for continuous monitoring of natural gas
pipelines. Our goal is to extract damage information from complex
guided wave patterns in pipes. We first review Time Reversal
methods, and discuss their effectiveness and limitation for
defect detection. Then, we describe our experimental results with
Time Reversal change detection which show that it is able to
detect small defects through its focusing effect. However, Time
Reversal is sensitive to changing environmental and operational
conditions, which may increase the false alarm rate. To reduce
the number of false positives, we propose a data mining framework
that integrates Time Reversal with data mining tools. The data
mining framework consists of three modules: defect detection,
defect localization, and defect classification. We explore the
potential use of Time Reversal in each work module. This paper
highlights these tasks and provides a clear work flow to further
our pipeline monitoring research.
based on Time Reversal for continuous monitoring of natural gas
pipelines. Our goal is to extract damage information from complex
guided wave patterns in pipes. We first review Time Reversal
methods, and discuss their effectiveness and limitation for
defect detection. Then, we describe our experimental results with
Time Reversal change detection which show that it is able to
detect small defects through its focusing effect. However, Time
Reversal is sensitive to changing environmental and operational
conditions, which may increase the false alarm rate. To reduce
the number of false positives, we propose a data mining framework
that integrates Time Reversal with data mining tools. The data
mining framework consists of three modules: defect detection,
defect localization, and defect classification. We explore the
potential use of Time Reversal in each work module. This paper
highlights these tasks and provides a clear work flow to further
our pipeline monitoring research.
13.
Yujie Ying, Joel Harley, James H Jr Garrett, Yuanwei Jin, José M F Moura, Nicholas O'Donoughue, Irving J Oppenheim, Lucio Soibelman
Time reversal for damage detection in pipes Proceedings Article
In: Tomizuka, Masayoshi (Ed.): Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010, pp. 1120–1131, SPIE, 2010.
@inproceedings{Ying2010-zv,
title = {Time reversal for damage detection in pipes},
author = {Yujie Ying and Joel Harley and James H Jr Garrett and Yuanwei Jin and José M F Moura and Nicholas O'Donoughue and Irving J Oppenheim and Lucio Soibelman},
editor = {Masayoshi Tomizuka},
url = {http://dx.doi.org/10.1117/12.847799},
doi = {10.1117/12.847799},
year = {2010},
date = {2010-03-01},
booktitle = {Sensors and Smart Structures Technologies for Civil, Mechanical,
and Aerospace Systems 2010},
volume = {7647},
pages = {1120–1131},
publisher = {SPIE},
abstract = {Monitoring the structural integrity of vast natural gas pipeline
networks requires continuous and economical inspection
technology. Current approaches for inspecting buried pipelines
require periodic excavation of sections of pipe to assess only a
couple of hundred meters at a time. These inspection systems for
pipelines are temporary and expensive. We propose to use
guided-wave ultrasonics with Time Reversal techniques to develop
an active sensing and continuous monitoring system. Pipe
environments are complex due to the presence of multiple modes
and high dispersion. These are treated as adverse effects by most
conventional ultrasonic techniques. However, Time Reversal takes
advantage of the multi-modal and dispersive behaviors to improve
the spatial and temporal wave focusing. In this paper, Time
Reversal process is mathematically described and experimentally
demonstrated through six laboratory experiments, providing
comprehensive and promising results on guided wave focusing in a
pipe with/without welded joint, with/without internal pressure,
and detection of three defects: lateral, longitudinal and
corrosion-like. The experimental results show that Time Reversal
can effectively compensate for multiple modes and dispersion in
pipes, resulting in an enhanced signal-to-noise ratio and
effective damage detection ability. As a consequence, Time
Reversal shows benefits in long-distance and lowpower pipeline
monitoring, as well as potential for applications in other
infrastructures.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Monitoring the structural integrity of vast natural gas pipeline
networks requires continuous and economical inspection
technology. Current approaches for inspecting buried pipelines
require periodic excavation of sections of pipe to assess only a
couple of hundred meters at a time. These inspection systems for
pipelines are temporary and expensive. We propose to use
guided-wave ultrasonics with Time Reversal techniques to develop
an active sensing and continuous monitoring system. Pipe
environments are complex due to the presence of multiple modes
and high dispersion. These are treated as adverse effects by most
conventional ultrasonic techniques. However, Time Reversal takes
advantage of the multi-modal and dispersive behaviors to improve
the spatial and temporal wave focusing. In this paper, Time
Reversal process is mathematically described and experimentally
demonstrated through six laboratory experiments, providing
comprehensive and promising results on guided wave focusing in a
pipe with/without welded joint, with/without internal pressure,
and detection of three defects: lateral, longitudinal and
corrosion-like. The experimental results show that Time Reversal
can effectively compensate for multiple modes and dispersion in
pipes, resulting in an enhanced signal-to-noise ratio and
effective damage detection ability. As a consequence, Time
Reversal shows benefits in long-distance and lowpower pipeline
monitoring, as well as potential for applications in other
infrastructures.
networks requires continuous and economical inspection
technology. Current approaches for inspecting buried pipelines
require periodic excavation of sections of pipe to assess only a
couple of hundred meters at a time. These inspection systems for
pipelines are temporary and expensive. We propose to use
guided-wave ultrasonics with Time Reversal techniques to develop
an active sensing and continuous monitoring system. Pipe
environments are complex due to the presence of multiple modes
and high dispersion. These are treated as adverse effects by most
conventional ultrasonic techniques. However, Time Reversal takes
advantage of the multi-modal and dispersive behaviors to improve
the spatial and temporal wave focusing. In this paper, Time
Reversal process is mathematically described and experimentally
demonstrated through six laboratory experiments, providing
comprehensive and promising results on guided wave focusing in a
pipe with/without welded joint, with/without internal pressure,
and detection of three defects: lateral, longitudinal and
corrosion-like. The experimental results show that Time Reversal
can effectively compensate for multiple modes and dispersion in
pipes, resulting in an enhanced signal-to-noise ratio and
effective damage detection ability. As a consequence, Time
Reversal shows benefits in long-distance and lowpower pipeline
monitoring, as well as potential for applications in other
infrastructures.
12.
Yuanwei Jin, Nicholas O'Donoughue, José M F Moura, Joel Harley, James H Garrett, Irving J Oppenheim, Lucio Soibelman, Yujie Ying, Lin He
Cognitive sensor networks for structure defect monitoring and classification using guided wave signals Proceedings Article
In: Tomizuka, Masayoshi (Ed.): Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010, pp. 1132–1143, SPIE, 2010.
@inproceedings{Jin2010-fw,
title = {Cognitive sensor networks for structure defect monitoring and
classification using guided wave signals},
author = {Yuanwei Jin and Nicholas O'Donoughue and José M F Moura and Joel Harley and James H Garrett and Irving J Oppenheim and Lucio Soibelman and Yujie Ying and Lin He},
editor = {Masayoshi Tomizuka},
url = {http://dx.doi.org/10.1117/12.848893},
doi = {10.1117/12.848893},
year = {2010},
date = {2010-03-01},
booktitle = {Sensors and Smart Structures Technologies for Civil, Mechanical,
and Aerospace Systems 2010},
volume = {7647},
pages = {1132–1143},
publisher = {SPIE},
abstract = {This paper develops a framework of a cognitive sensor networks
system for structure defect monitoring and classification using
guided wave signals. Guided ultrasonic waves that can propagate
long distances along civil structures have been widely studied
for inspection and detection of structure damage. Smart
ultrasonic sensors arranged as a spatially distributed cognitive
sensor networks system can transmit and receive ultrasonic guided
waves to interrogate structure defects such as cracks and
corrosion. A distinguishing characteristic of the cognitive
sensor networks system is that it adaptively probes and learns
about the environment, which enables constant optimization in
response to its changing understanding of the defect response. In
this paper, we develop a sequential multiple hypothesis testing
scheme combined with adaptive waveform transmission for defect
monitoring and classification. The performance is verified using
numerical simulations of guided elastic wave propagation on a
pipe model and by Monte Carlo simulations for computing the
probability of correct classification.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper develops a framework of a cognitive sensor networks
system for structure defect monitoring and classification using
guided wave signals. Guided ultrasonic waves that can propagate
long distances along civil structures have been widely studied
for inspection and detection of structure damage. Smart
ultrasonic sensors arranged as a spatially distributed cognitive
sensor networks system can transmit and receive ultrasonic guided
waves to interrogate structure defects such as cracks and
corrosion. A distinguishing characteristic of the cognitive
sensor networks system is that it adaptively probes and learns
about the environment, which enables constant optimization in
response to its changing understanding of the defect response. In
this paper, we develop a sequential multiple hypothesis testing
scheme combined with adaptive waveform transmission for defect
monitoring and classification. The performance is verified using
numerical simulations of guided elastic wave propagation on a
pipe model and by Monte Carlo simulations for computing the
probability of correct classification.
system for structure defect monitoring and classification using
guided wave signals. Guided ultrasonic waves that can propagate
long distances along civil structures have been widely studied
for inspection and detection of structure damage. Smart
ultrasonic sensors arranged as a spatially distributed cognitive
sensor networks system can transmit and receive ultrasonic guided
waves to interrogate structure defects such as cracks and
corrosion. A distinguishing characteristic of the cognitive
sensor networks system is that it adaptively probes and learns
about the environment, which enables constant optimization in
response to its changing understanding of the defect response. In
this paper, we develop a sequential multiple hypothesis testing
scheme combined with adaptive waveform transmission for defect
monitoring and classification. The performance is verified using
numerical simulations of guided elastic wave propagation on a
pipe model and by Monte Carlo simulations for computing the
probability of correct classification.
11.
Yuanwei Jin, Jose M F Moura, Nicholas O'Donoughue, Joel Harley
Single antenna time reversal detection of moving target Proceedings Article
In: 2010 IEEE International Conference on Acoustics, Speech and Signal Processing, pp. 3558–3561, IEEE, Dallas, TX, 2010.
@inproceedings{Jin2010-hp,
title = {Single antenna time reversal detection of moving target},
author = {Yuanwei Jin and Jose M F Moura and Nicholas O'Donoughue and Joel Harley},
url = {http://dx.doi.org/10.1109/ICASSP.2010.5495928},
doi = {10.1109/ICASSP.2010.5495928},
year = {2010},
date = {2010-03-01},
booktitle = {2010 IEEE International Conference on Acoustics, Speech and
Signal Processing},
pages = {3558–3561},
publisher = {IEEE},
address = {Dallas, TX},
abstract = {This paper is concerned with a moving target detection using time
reversal in dense multipath environments. We show that the
Doppler shift in the time reversal re-transmission simplifies the
detector design, yet still achieves the focusing effect. Thus,
the Doppler diversity is utilized to achieve high target
detectability by time reversal.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper is concerned with a moving target detection using time
reversal in dense multipath environments. We show that the
Doppler shift in the time reversal re-transmission simplifies the
detector design, yet still achieves the focusing effect. Thus,
the Doppler diversity is utilized to achieve high target
detectability by time reversal.
reversal in dense multipath environments. We show that the
Doppler shift in the time reversal re-transmission simplifies the
detector design, yet still achieves the focusing effect. Thus,
the Doppler diversity is utilized to achieve high target
detectability by time reversal.
10.
Joel Harley, Nicholas O'Donoughue, Yuanwei Jin, Jose M Moura
Time Reversal Focusing for Pipeline Structural Health Monitoring Proceedings Article
In: Proc. of Meetings on Acoustics, pp. 030001–030001, ASA, San Antonio, TX, 2010.
@inproceedings{Harley2010-nw,
title = {Time Reversal Focusing for Pipeline Structural Health Monitoring},
author = {Joel Harley and Nicholas O'Donoughue and Yuanwei Jin and Jose M Moura},
url = {http://asa.scitation.org/doi/abs/10.1121/1.3309475},
doi = {10.1121/1.3309475},
year = {2010},
date = {2010-01-01},
booktitle = {Proc. of Meetings on Acoustics},
volume = {8},
pages = {030001–030001},
publisher = {ASA},
address = {San Antonio, TX},
series = {Proceedings of Meetings on Acoustics},
abstract = {This paper investigates the use of time reversal processing
techniques to compensate for multimodal and dispersive effects in
a low-power structural health monitoring system for pipelines. We
demonstrate the use of time reversal as a pitch-catch operation
between two transducer arrays to illuminate changes caused by
damage on a pipe. We then show and discuss how differences in the
severity of damage affect the signals recorded at the receiving
transducer array and demonstrate how these results can be
interpreted to measure those changes. Our results are
demonstrated through experimental observation.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper investigates the use of time reversal processing
techniques to compensate for multimodal and dispersive effects in
a low-power structural health monitoring system for pipelines. We
demonstrate the use of time reversal as a pitch-catch operation
between two transducer arrays to illuminate changes caused by
damage on a pipe. We then show and discuss how differences in the
severity of damage affect the signals recorded at the receiving
transducer array and demonstrate how these results can be
interpreted to measure those changes. Our results are
demonstrated through experimental observation.
techniques to compensate for multimodal and dispersive effects in
a low-power structural health monitoring system for pipelines. We
demonstrate the use of time reversal as a pitch-catch operation
between two transducer arrays to illuminate changes caused by
damage on a pipe. We then show and discuss how differences in the
severity of damage affect the signals recorded at the receiving
transducer array and demonstrate how these results can be
interpreted to measure those changes. Our results are
demonstrated through experimental observation.
2009
9.
N O'Donoughue, J Harley, J M F Moura, Y Jin
Detection of structural defects in pipes using time reversal of guided waves Proceedings Article
In: 2009 Conference Record of the Forty-Third Asilomar Conference on Signals, Systems and Computers, pp. 1683–1686, IEEE, Pacific Grove, CA, 2009.
@inproceedings{ODonoughue2009-da,
title = {Detection of structural defects in pipes using time reversal of
guided waves},
author = {N O'Donoughue and J Harley and J M F Moura and Y Jin},
url = {http://dx.doi.org/10.1109/ACSSC.2009.5469779},
doi = {10.1109/ACSSC.2009.5469779},
year = {2009},
date = {2009-11-01},
booktitle = {2009 Conference Record of the Forty-Third Asilomar Conference on
Signals, Systems and Computers},
pages = {1683–1686},
publisher = {IEEE},
address = {Pacific Grove, CA},
abstract = {Structural health monitoring of buried pipelines is of vital
importance as infrastructures age. Ultrasonic guided waves are a
popular method for inspecting buried pipes, due to their
potential for long propagation. Unfortunately, the large number
of wave modes present, and the effects of dispersion, in a
pipeline make analysis of the received signals difficult. We plan
to use Time Reversal Acoustics to compensate for these complex
signals, and improve performance for the detection of faults in a
pipeline. We will present theoretical performance results for
conventional and Time Reversal detectors, verified with
simulations conducted in PZFlex. Time Reversal shows a potential
for a reduction in the power requirements of a fault detection
system.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Structural health monitoring of buried pipelines is of vital
importance as infrastructures age. Ultrasonic guided waves are a
popular method for inspecting buried pipes, due to their
potential for long propagation. Unfortunately, the large number
of wave modes present, and the effects of dispersion, in a
pipeline make analysis of the received signals difficult. We plan
to use Time Reversal Acoustics to compensate for these complex
signals, and improve performance for the detection of faults in a
pipeline. We will present theoretical performance results for
conventional and Time Reversal detectors, verified with
simulations conducted in PZFlex. Time Reversal shows a potential
for a reduction in the power requirements of a fault detection
system.
importance as infrastructures age. Ultrasonic guided waves are a
popular method for inspecting buried pipes, due to their
potential for long propagation. Unfortunately, the large number
of wave modes present, and the effects of dispersion, in a
pipeline make analysis of the received signals difficult. We plan
to use Time Reversal Acoustics to compensate for these complex
signals, and improve performance for the detection of faults in a
pipeline. We will present theoretical performance results for
conventional and Time Reversal detectors, verified with
simulations conducted in PZFlex. Time Reversal shows a potential
for a reduction in the power requirements of a fault detection
system.
8.
Joel Harley, Nicholas O'Donoughue, Joseph States, Yujie Ying, James H Garrett, Yuanwei Jin, José M F Moura, Irving J Oppenheim, Lucio Soibelman
Focusing of ultrasonic waves in cylindrical shells using time reversal Proceedings Article
In: Proc. of the International Workshop on Structural Health Monitoring, pp. 283–291, Stanford, CA, 2009.
@inproceedings{Harley2009-yy,
title = {Focusing of ultrasonic waves in cylindrical shells using time
reversal},
author = {Joel Harley and Nicholas O'Donoughue and Joseph States and Yujie Ying and James H Garrett and Yuanwei Jin and José M F Moura and Irving J Oppenheim and Lucio Soibelman},
year = {2009},
date = {2009-09-01},
booktitle = {Proc. of the International Workshop on Structural Health
Monitoring},
pages = {283–291},
address = {Stanford, CA},
abstract = {This paper investigates time reversal focusing techniques for the
development of low-power, long-range, structural health
monitoring applications for pipelines. We analytically examine
time reversal’s ability to compensate for unwanted multimodal and
dispersive behavior that are characteristic of guided waves
travelling through pipes. We then develop a method to illuminate
changes caused by structural damage using time reversal focusing
as a pitch-catch operation. Using experimental and finite element
simulation results with two transducers, we demonstrate these
concepts and show that time reversal focusing provides a clear,
interpretable metric for the characterization of damage in a
pipe.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper investigates time reversal focusing techniques for the
development of low-power, long-range, structural health
monitoring applications for pipelines. We analytically examine
time reversal’s ability to compensate for unwanted multimodal and
dispersive behavior that are characteristic of guided waves
travelling through pipes. We then develop a method to illuminate
changes caused by structural damage using time reversal focusing
as a pitch-catch operation. Using experimental and finite element
simulation results with two transducers, we demonstrate these
concepts and show that time reversal focusing provides a clear,
interpretable metric for the characterization of damage in a
pipe.
development of low-power, long-range, structural health
monitoring applications for pipelines. We analytically examine
time reversal’s ability to compensate for unwanted multimodal and
dispersive behavior that are characteristic of guided waves
travelling through pipes. We then develop a method to illuminate
changes caused by structural damage using time reversal focusing
as a pitch-catch operation. Using experimental and finite element
simulation results with two transducers, we demonstrate these
concepts and show that time reversal focusing provides a clear,
interpretable metric for the characterization of damage in a
pipe.
7.
Nicholas O'Donoughue, Joel Harley, Jose M Moura, Yuanwei Jin, Irving Oppenheim, Yujie Ying, Joseph States, James Garrett, Lucio Soibelman
Single antenna time reversal of guided waves in pipelines Proceedings Article
In: ASA, 2009.
@inproceedings{O-Donoughue2009-ua,
title = {Single antenna time reversal of guided waves in pipelines},
author = {Nicholas O'Donoughue and Joel Harley and Jose M Moura and Yuanwei Jin and Irving Oppenheim and Yujie Ying and Joseph States and James Garrett and Lucio Soibelman},
url = {http://dx.doi.org/10.1121/1.3155375/18233778/pma.v6.i1.065001_1.online},
doi = {10.1121/1.3155375},
year = {2009},
date = {2009-01-01},
publisher = {ASA},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
6.
Nicholas O'Donoughue, Joel Harley, Jose M Moura, Yuanwei Jin, Irving Oppenheim, Yujie Ying, Joseph States, James Garrett, Lucio Soibelman
Single Antenna Time Reversal of Guided Waves in Pipelines Proceedings Article
In: Proc. of Meetings on Acoustics, pp. 065001–065001, ASA, Portland, OR, 2009.
@inproceedings{ODonoughue2009-se,
title = {Single Antenna Time Reversal of Guided Waves in Pipelines},
author = {Nicholas O'Donoughue and Joel Harley and Jose M Moura and Yuanwei Jin and Irving Oppenheim and Yujie Ying and Joseph States and James Garrett and Lucio Soibelman},
url = {http://asa.scitation.org/doi/abs/10.1121/1.3155375},
doi = {10.1121/1.3155375},
year = {2009},
date = {2009-01-01},
booktitle = {Proc. of Meetings on Acoustics},
volume = {6},
pages = {065001–065001},
publisher = {ASA},
address = {Portland, OR},
series = {Proceedings of Meetings on Acoustics},
abstract = {The volatile nature of natural gas makes it extremely important
to ensure that distribution pipelines remain free from defects,
as leakage can result in explosions. Many current methods for
testing buried pipelines rely on periodic excavation of a section
of pipe and attachment of large acoustic or magneto-restrictive
sensors. These systems, while reliable, suffer from a high
cost-per-test ratio. Our group hopes to reduce the power
constraints of such a detection system, in order to allow for
permanent installations that monitor the pipelines continuously.
We propose to use Time Reversal, a signal processing technique,
in order to achieve this improvement. This paper will focus on
the modes generated by various acoustic probing signals, and the
echoes received with and without Time Reversal. We argue that TR
will be most beneficial when there are several dispersive modes
present, a scenario avoided in conventional techniques. We will
present simulation results for the analysis of wave modes in a
cylindrical pipe before and after Time Reversal using PZFlex.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
The volatile nature of natural gas makes it extremely important
to ensure that distribution pipelines remain free from defects,
as leakage can result in explosions. Many current methods for
testing buried pipelines rely on periodic excavation of a section
of pipe and attachment of large acoustic or magneto-restrictive
sensors. These systems, while reliable, suffer from a high
cost-per-test ratio. Our group hopes to reduce the power
constraints of such a detection system, in order to allow for
permanent installations that monitor the pipelines continuously.
We propose to use Time Reversal, a signal processing technique,
in order to achieve this improvement. This paper will focus on
the modes generated by various acoustic probing signals, and the
echoes received with and without Time Reversal. We argue that TR
will be most beneficial when there are several dispersive modes
present, a scenario avoided in conventional techniques. We will
present simulation results for the analysis of wave modes in a
cylindrical pipe before and after Time Reversal using PZFlex.
to ensure that distribution pipelines remain free from defects,
as leakage can result in explosions. Many current methods for
testing buried pipelines rely on periodic excavation of a section
of pipe and attachment of large acoustic or magneto-restrictive
sensors. These systems, while reliable, suffer from a high
cost-per-test ratio. Our group hopes to reduce the power
constraints of such a detection system, in order to allow for
permanent installations that monitor the pipelines continuously.
We propose to use Time Reversal, a signal processing technique,
in order to achieve this improvement. This paper will focus on
the modes generated by various acoustic probing signals, and the
echoes received with and without Time Reversal. We argue that TR
will be most beneficial when there are several dispersive modes
present, a scenario avoided in conventional techniques. We will
present simulation results for the analysis of wave modes in a
cylindrical pipe before and after Time Reversal using PZFlex.
5.
Joel Harley, Nicholas O’Donoughue, José M F Moura, Yuanwei Jin
Time reversal focusing for pipeline structural health monitoring Journal Article
In: The Journal of the Acoustical Society of America, vol. 126, no. 4, pp. 2197, 2009.
@article{Harley2009-se,
title = {Time reversal focusing for pipeline structural health monitoring},
author = {Joel Harley and Nicholas O’Donoughue and José M F Moura and Yuanwei Jin},
url = {http://scitation.aip.org/content/asa/journal/jasa/126/4/10.1121/1.3248592},
doi = {10.1121/1.3248592},
year = {2009},
date = {2009-01-01},
journal = {The Journal of the Acoustical Society of America},
volume = {126},
number = {4},
pages = {2197},
publisher = {Acoustical Society of America (ASA)},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2006
4.
A V Giannopoulos, A M Kasten, C Long, C Chen, J Harley, K D Choquette
2-dimensional Integrated VCSEL and PIN Photodector Arrays for Bidirectional Optical Links Proceedings Article
In: LEOS 2006 - 19th Annual Meeting of the IEEE Lasers and Electro-Optics Society, pp. 448–449, Montreal, QC, 2006.
@inproceedings{Giannopoulos2006-fd,
title = {2-dimensional Integrated VCSEL and PIN Photodector Arrays for
Bidirectional Optical Links},
author = {A V Giannopoulos and A M Kasten and C Long and C Chen and J Harley and K D Choquette},
url = {http://ieeexplore.ieee.org/Xplore/login.jsp?reload=true&url=http://ieeexplore.ieee.org/iel5/4054018/4054019/04054250.pdf?arnumber=4054250&authDecision=-203},
doi = {10.1109/LEOS.2006.279208},
year = {2006},
date = {2006-10-01},
booktitle = {LEOS 2006 - 19th Annual Meeting of the IEEE Lasers and
Electro-Optics Society},
pages = {448–449},
address = {Montreal, QC},
abstract = {We have designed and fabricated hexagonal, 2-dimensional,
integrated VCSEL and PIN photodetector linear arrays for optical
communications. Device characteristics were observed to be
uniform across the entire array. This in addition to the mirror
symmetry of the die, allows for the usage of these arrays as
optical transceivers},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
We have designed and fabricated hexagonal, 2-dimensional,
integrated VCSEL and PIN photodetector linear arrays for optical
communications. Device characteristics were observed to be
uniform across the entire array. This in addition to the mirror
symmetry of the die, allows for the usage of these arrays as
optical transceivers
integrated VCSEL and PIN photodetector linear arrays for optical
communications. Device characteristics were observed to be
uniform across the entire array. This in addition to the mirror
symmetry of the die, allows for the usage of these arrays as
optical transceivers