Organizer:
Ship and Ocean Technology Research Center
Department of Engineering Science and Ocean Engineering, National Taiwan University
Co-organizer:
OceanSound Co. Inc.
Sponsors: Ministry of Science and Technology, Taiwan Office of Naval Research, USA
Office of Naval Research Global, USA
National Taiwan University, Taiwan Acoustical Society of America, USA
International Ocean and Atmosphere Research
Development Foundation, Taiwan
Editor:
Chi-Fang Chen
Mei-Yuh Shih
National Taiwan University
Published by:
National Taiwan University, Taipei, Taiwan
http:// pruac2018.esoe.ntu.edu.tw/
September 2018
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The 6th Pacific Rim Underwater Acoustic Conference
Contents
I Information
Welcome to PRUAC2018……………………………………………. 2
General Information…………………………………………………. 3
Scientific Committee………………………………………………… 3
Local Committee…………………………………………………….. 4
Working Group………………………………………………………. 5
Plenary Speakers……………………………………………………... 6
Practical Information………………………………………………… 7
IceBreaker: Cosmos Hotel, Taipei…………………………………… 7
Conference Venue: FarGlory Hotel………………………………….. 7
Information for Presenters…………………………………………… 8
Coffee & Lunch……………………………………………………… 8
WiFi at the Venue……………………………………………………. 8
Social Events………………………………………………………….. 9
Welcome Reception………………………………………………….. 9
Two-hour Train Excursion…………………………………………… 9
Conference Banquet………………………………………………….. 9
Local Tour to Taroko National Park………………………………… 9
II. Abstracts
Ross Norman Chapman, Sounds in the Ocean: Experiments and
Measurements in Underwater Acoustics.12
Michael Porter, Laurel J. Henderson, John Peterson, Tim Duda, Arthur
Newhall, Peter Traykovski. Fully 3D Sound Propagation in the
Weymouth Fore River, with a Dry-Dock and a Ship Hull.
13
Yuanliang Ma, Yixin Yang, Yong Wang. Underwater Acoustic Sensor
Array Processing: Problems and Improving Approaches.14
Ruijie Meng, Shihong Zhou, Fenghua Li. Radial Velocity Estimation of
Moving Source Using Pressure Difference of Dual Hydrophones.15
Zhao Zhen Dong, J. Zeng, L. Ma, E. C. Shang. A Model-free Approach
for Inverting the Intrinsic Attenuationα(f) of Sea-bed Sediment.16
T. C. Yang, S. H. Huang. Deconvolved Conventional Beamforming
Applied to the SW06 and SWellEx96 Data.17
Juan Zeng, Z.D. Zhao, L. Ma, E. C. Shang. A Simple Estimation of the
Seabed Sound Speed with the Group Speed of the Critical Mode. 18
Gee-Pinn James Too, Lin-Hua Hsu, Kuan-Yuan Chen. Comparison of 19
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The 6th Pacific Rim Underwater Acoustic Conference
Alternative Underwater Communication Modulation Schemes in
Various Conditions.
Xiao Chuan Ma, Chao Feng. An Effective System Modeling Method
for the Reduction of Low Frequency Noise from Marine Detection
UUVs.
20
Wen Xu, Lianlong Li. 2016 Shallow-Water Experiment on Ocean
Acoustic-Dynamic Coupled Data Assimilation in South China Sea. 21
Yan Zhang, Shihong Zhou. A Range-estimation Method for Surface
Sources Based on the Characteristic of Bottom Bounced Sound in
Deep Water.
22
Zhenglin Li, Renhe Zhang, Zhiguo Hu. Sound Propagation in Deep
Water with a Sloping Bottom. 23
Shuyuan Du, Shihong Zhou, Yubo Qi . Full Wavefield Computation and
Propagation Simulations in Typical Irregular Seabottom Environment. 24
Fei-Yun Wu, Kun-de Yang, Rui Duan, Hui Li. An Improved Non-
uniform Norm Method for Sparse Channel Estimation. 25
Alexey O. Maksimov, Yu A. Polovinka. Bubble Dynamics Near an
Interface. 26
Ching-Sang Chiu, Linus Y. S. Chiu, Chi-Fang Chen, Yiing Jang Yang,
Jiann-Yuh Lou, Christopher W. Miller. Geoacoustic Properties of, and
Propagation Anisotropy Induced by, Subaqueous Sand Dunes on the
Upper-slope of the Northeastern South China Sea.
27
Ying-Tsong Lin, Underwater Sound Pressure Sensitivity in Three-
Dimensional Oceanic Environments. 28
Tiago Oliveira, Ying-Tsong Lin, Towards 3D Global Scale Underwater
Sound Modeling. 29
Linus Chiu, Ching-Sang Chiu, Chi-Fang Chen, Yiing-Jian Yang, Ruey-
Chang Wei, Andrea Chang, Acoustic Propagation Effects of
Subaqueous Sand Dune Bedforms in the South China Sea.
30
Douglas Herrod Cato, Challenges and Progress in the Study of the
Effects of Noise on Marine Life. 31
Tomonari Akamatsu, Assessment of Noise Impacts on Marine
Organisms. 32
Siddagangaiah Shashidhar, Chi-Fang Chen, Silent Winters: Long
Term Study of Fish Chorusing and Evidence of Impact of Continual
Shipping Noise on Fishes.
33
Dong-Gyun Han, Jee Woong Choi, Jungyul Na. Measurements of Pile
Driving Noise from Offshore Wind Farm Construction in Southwest
Coast of Korea.
34
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The 6th Pacific Rim Underwater Acoustic Conference
Roberto Racca, Graham Warner, Alexander MacGillivray, Jorge
Quijano, Melanie Austin. Calculating Marine Mammal Harassment
Zones from Hydroacoustic Measurements and Modelling of Pile
Driving Operations.
35
Pai-Ho Chiu, Ruey-Chang Wei, Hin-Kiu Mok, Keryea Soong,
Soundscape in Shallow Water of Dongsha Island, South China Sea. 36
Matthew Pine, Ding Wang, Lindsay Porter, Francis Juanes, Kexiong
Wang. Changes to the Fine-scale Habitat Use in Indo-Pacific
Humpback Dolphins in Relation to Vessel Traffic in Hong Kong SAR.
37
III Posters
Yeon-Seong Choo, Sung-Hoon Byun, Sea-Moon Kim and Keunhwa
Lee. Observation of Acoustic Echoes from Aluminum Hollow Sphere
Using a Horizontal Line Array.
39
Cheng Jiang, Wen Xu, Jianlong Li and Zhongyue Chen. Temporal-
Spatial Aggregation in Underwater Acoustic Passive Detection with A
Mobile Node.
40
Donghyeon Kim, Yonghwa Choi, Gihoon Byun, Seongil Cho and
Jeasoo Kim, Direction Finding of Snapping Shrimp Based on Δf - k
Spectrum.
41
Sehyun Lee, Keunhwa Lee, Jun-Seok Lim, Myoung-Jun Cheong.
Waveform Design for Compressive Sensing Active SONAR. 42
Wei-Lun Li, Wei-Yen Chu and Chi-Fang Chen. Dolphin Whistle
Detection. 43
Jingyao Liang, Ting Zhang, Wen Xu. Passive Localization Based on
Distributed Network via Double-Correlation Function of Opportunity
Sources.
44
Kuan-Wen Liu, and Ching-Jer Huang. Real-time Monitoring of
Underwater Sound Using a Buoy Installed with a Hydrophone 45
Raegeun Oh, Bon-Sung Gu, Taek-Lyul Song and Jee Woong Choi.
Correction of Bearing Error of Line Array Sonar System Due to
Bottom Bounced Path Signal
46
Ping-Jung Sung, and Chi-Fang Chen. Pile Driving Noise Simulation
and Analysis (Exhibition only)
Yin-Ying Fang, Chi-Fang Chen and Sheng-Ju Wu, Optimization of
Acoustic Signature Identification System for Ocean Researcher III
(OR3) (Exhibition only)
Dong Hwan Jung and J. S. Kim. Simple Method Using Zero Crossing
of Envelope for Time Delay Estimation. (Exhibition only)
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The 6th Pacific Rim Underwater Acoustic Conference
Presenters Index 47
Conference Program 49
1
Information
PART I
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The 6th Pacific Rim Underwater Acoustic Conference
Welcome to PRUAC2018
Dear Participants,
May we extend our hearty welcome to you all! Welcome to Taiwan for the
PRUAC2018, the 6th Pacific Rim Underwater Acoustic Conference. We welcome the
distinguished guests and speakers from 9 countries of the world.
We are thankful to co-organizer, the Ocean Sound work together with us to make
this meeting possible. We also are thankful to the Ministry of Science and Technology
(MOST) of Taiwan, National Taiwan University, International Ocean & Atmosphere
Research Development (IOAR), and ONR (Office of Naval Research), ONRG (Office
of Naval Research Global), Acoustical Society of America (ASA) who sponsor and
support us in various aspects.
We are very blessed to have Dr. Ross Chapman, Dr. Douglas Cato and Dr. Michael
Buckingham who are worldly renowned speakers who have accepted our invitation as
plenary speakers though Dr. Buckingham due to health reason cannot make it at the end.
In the PRUAC2018, we have 26 papers from 9 countries; namely, Australia,
Canada, China, Japan, Korea, Russia, Singapore, USA and Taiwan. The papers are
mostly from the academic sector, some are from industrial sector and/or the
collaboration of the both sectors. And, their focuses are on conference theme: (1)
Underwater Noise Impacts on Marine Life and Acoustic Monitoring of Marine Life,
and, (2) Underwater Acoustic Studies in Littoral Waters.
The PRUAC2018 will give award of USD900 to top three graduate students who
compete and present posters in the event. We have received 11 contributed posters
from students of three countries. One Student Awards Committee of 12, from six
countries, chaired by Dr. Andrea Y. Y. Chang will evaluate the creativity, the design and
the speed talk of the research. We give thanks to the ASA for offering and encouraging
students this excellent chance to participate the meeting and to compete poster.
As always, we appreciate the Office of Naval Research (ONR) and Office of Naval
Research Global (ONRG) for generously support this academic and research event.
Last but most important, let us give thanks to all the participants who are of various
generations, cultures and research specialties to come from afar to join us. May we wish
your stay in Taiwan a joyous and unforgettable one.
Chi-Fang Chen
Professor
National Taiwan University, Taiwan
Chairman
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The 6th Pacific Rim Underwater Acoustic Conference
General Information _____________________________________________
Conference Chairman
Chi-Fang Chen
Professor
National Taiwan University, Taipei, Taiwan
Scientific Committee
Chi-Fang Chen National Taiwan University, Taiwan
Tomonari Akamatsu Fisheries Research and Education Agency, Japan
Michael Buckingham Scripps Institution of Oceanography, USA
Douglas Cato University of Sydney, Australia
Ross Chapman University of Victoria, Canada
Ching Sang Chiu Naval Postgraduate School, USA
Jee Woong Choi Korea Maritime and Ocean University, Republic of Korea
Peter Dahl University of Washington, USA
Jea-soo Kim Korea Maritime and Ocean University, Republic of Korea
William Kuperman Scripps Institution of Oceanography, USA
Fenghua Li Chinese Academy of Sciences, China
Ying-Tsong Lin Woods Hole Oceanographic Institution, USA
Yuanliang Ma Northwestern Polytechnical University, China
Michael Porter Heat, Light and Sound Research, Inc., USA
Gang Qiao Harbin Engineering University, China
Roberto Racca JASCO Applied Sciences, Canada
Er-Chang Shang Chinese Academy of Sciences, China
Jeffrey Simmen Office of Naval Research Global (ONRG)
Robert Spindel University of Washington, USA
Wen Xu Zhejiang University, China
Juan Zeng Chinese Academy of Sciences, China
Renhe Zhang Chinese Academy of Sciences, China
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The 6th Pacific Rim Underwater Acoustic Conference
Local Committee
Chi-Fang Chen National Taiwan University
Andrea Y. Y. Chang National Sun Yat-sen University
Mao-Hsiung Chiang National Taiwan University
Linus Y.S Chiu National Sun Yat-sen University
C. J. Huang National Cheng Kung University
Sheng-Fong Lin National Kaohsiung University of Science and Technology
Gee-Pinn James Too National Cheng Kung University
Jing-Fa Tsai National Taiwan University
Chung-Wu Wang Ocean Sound Co., Ltd.
Ruey-Chang Wei National Sun Yat-sen University
Wei-Cheng Yang National Taiwan University
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The 6th Pacific Rim Underwater Acoustic Conference
Working Group
Secretary: Mei-yuh Shih
Activity Team
Ching-Tang Hung
MengFan Tsai
Yao Sung Hsu
I Yun Su
Kuan Jung Pan
Hsu Yong Hung
You Cheng Zhang
Reception Team
Ying-Rong Chen
Charlie Chiao-Ming Peng
York Chu
Yun-Dian Fan Jiang
Tai-Hua Liu
Chiu Kuan Shih
Hsiang-Hsuan Jan
Venue Team
Yen-Hsiang Huang
Peng-Kuei Chen
Hsiang-Hsuan Chao
Wei-Yen Chiu
Ping Jung Sung
Wei-Lun Li
Ming-Chou Wu
Academic Team
Shashidhar Siddagangaiah
Wendy Yin-Ying Fang
Wen-Yang Liu
Angela Hsieh
IT Team
William Hu
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The 6th Pacific Rim Underwater Acoustic Conference
Plenary Speakers
Plenary Lecture
Ross Norman Chapman (University of Victoria,
Canada) will give lecture on Sounds in the Ocean:
Experiments and Measurements in Underwater Acoustics.
Professor Chapman is an Emeritus Faculty and Chair of
Ocean Acoustics at the University of Victoria in Victoria, British Columbia, Canada,
He is a Fellow of the Institute of Electrical and Electronic Engineers (IEEE) and the
Acoustical Society of America, and previously Editor in Chief of the IEEE Journal of
Oceanic Engineering. He has published over 150 research papers and chapters in
journals and books, and is internationally known for his work in ocean acoustics
propagation, geoacoustic inversion and ambient noise. Professor Chapman is a
founder of the PRUAC conference series, and his participation enhances the stature of
the event.
Douglas Herrod Cato (University of Sydney, Australia) will give lecture on
Challenges and Progress in the Study of the Effects of Noise on
Marine Life.
Professor Cato is an adjunct professor of the School of
Geosciences and Marine Studies Centre, University of
Sydney. His research includes underwater acoustics,
particularly the ambient noise and soundscapes of the
ocean, marine bioacoustics and the effects of noise on
marine animals. Recent work includes a project on the
effects of the noise of seismic surveys on humpback whale
behavior. He has more than 50 years’ experience in underwater
acoustics, and more than 35 years’ experience in marine bioacoustics, including
experimental work in the laboratory and at sea, and as chief scientist of many sea
experiments.
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The 6th Pacific Rim Underwater Acoustic Conference
Practical Information
IceBreaker: Cosmos Hotel, Taipei
The IceBreaker of PRUAC2018 will take place in Cheer Banquet Room of the
Cosmos Hotel Taipei. The Cosmos Hotel Taipei is conveniently located next to the
M3 exit of MRT’s Taipei Station stop, at the heart of Taipei’s well establish public
transit system. Since its opening in 1979, Cosmos Hotel has been the hotel of choice
for many international tourists and business travelers, as well as a popular destination
for corporate meetings and group seminars.
Conference Venue: FarGlory Hotel
The conference will be held at the Farglory Hotel of HuaLien, Taiwan. Farglory
Hotel stands 220 meters high and covers dozens of hectares. With the mountains to
one side and the ocean to the other, Farglory Hotel is also close to Farglory Ocean
Park, Hualien. Be it of the nearby Mugua Stream, the Central Mountains, Hualien
City, or the Pacific Ocean, the hotel offers an amazingly clear vista.
The meeting and poster exhibition will take place in Windsor House; coffee breaks
and exhibition will take place in front of the Victoria House.
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The 6th Pacific Rim Underwater Acoustic Conference
Information for Presenters
The meeting room, Windsor House, of FarGlory Hotel is equipped with projector,
computer and laser pointer. One of the organizer staff will assist you. You may
update and/or download your presentation PowerPoint 15 minutes before the start of
each session.
Coffee & Meals
Drinks, coffee and snacks will be provided on the banquet foyer, in front of the
Windsor House.
Breakfast will be served with buffet, lunch and dinner meals are mostly of Chinese
cuisine. And, we will be served by sitting around the table.
WiFi at the Venue
WiFi is available in the FarGlory Hotel. Conference participants can get access to
Internet anywhere in the hotel.
Meeting Room (Windsor House) & Banquet Foyer
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The 6th Pacific Rim Underwater Acoustic Conference
Social Events
Welcome Reception
Sunday, 2 September 2018, 13:30-14:00: The welcome reception (IceBreaker) will
be held at Cheer Hall of the Cosmos Hotel Taipei. Registration will be done from
13:30-14:00, the Welcome (IceBreaker) will be followed, 14:00-16:00. Light drinks,
coffee and snacks will be served. Friends from local as well as other parts of the
world will get to know each other, you will meet with old as well as new friends.
Two-hour Train Excursion
The scenery along the road between Taipei to HuaLien is very pretty. After the
IceBreaker, we will all take, around two hours, the same train carriage to conference
venue. On the train, we can read, play card, rest and make new friends.
Conference Banquet
Monday, 3 September 2018, 18:30-21:00, Victoria House
We will have dinner banquet in the house of the Victorian style architecture. Chinese
cuisine will be served. Many honorable guests will be invited to share their insights
and close relationship with the PRUAC. You are encouraged to say a few words to all
the participants.
Local Tour to Taroko National Park
Tuesday, September 4, 2018, 10:00-18:00
We will take a local tour to Taroko National Park which is one of the nine national
Parks in Taiwan. This park is named after the Taroko Gorge. This Gorge and its
surrounding area are well known for their abundant supply of marble, leading to its
nickname, ‘The Marble Gorge’. There are
many trails, tunnels, temples and cliffs in the
park. We will have an unusual and exciting
experiences from this tour.
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The 6th Pacific Rim Underwater Acoustic Conference
ABSTRACTS
Part II
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The 6th Pacific Rim Underwater Acoustic Conference
Sounds in the Ocean: Experiments and Measurements in Underwater Acoustics
Ross Chapman
University of Victoria, Canada
ABSTRACT
For this lecture, professor Chapman will talk about the objective of the presentation
is two-fold: first to show what we have learned about sound transmission in the ocean
from the results of simple experiments, and second, to show the linkage between ocean
acoustics and knowledge about ocean properties and structure from oceanographic
research. Our interpretation of results from acoustic experiments has to be framed
within the reality of physical processes in and properties of the ocean that determine
the nature of sound propagation.
The plan for the lecture is to show examples of data from experiments with sound
sources and receivers, and then describe the conclusions that can be drawn about the
nature of sound transmission. Results are shown from experiments to measure
transmission loss in deep oceans that were crucial in providing new knowledge about
the ocean as an acoustic lens that enabled sound propagation to long ranges.
Transmission loss is based on measurements of the acoustic intensity, so the
presentation then looks at the additional information that is obtained from the phase of
the sound signal. Examples are presented that illustrate the use of full field data to
enable detection of distant sound sources with arrays of hydrophones, location of sound
sources and inversion of ocean environmental properties using matched field
processing. Acoustics of shallow water environments is discussed in terms of
experimental measurements of normal modes, and examples are shown to illustrate the
use of modes for inversion of models of the ocean environment. Finally, the
presentation introduces measurements of ambient noise and describes its use as a sound
source. For each theme that is presented, reference is made to present day research
that is continuing in the theme.
The 6th Pacific Rim Underwater Acoustic Conference
Fully 3D Sound Propagation in the Weymouth Fore River,
with a Dry-Dock and a Ship Hull
*Michael B. Porter1, Laurel J. Henderson1, and John Peterson1, Tim Duda2,
Arthur Newhall2, Peter Traykovski2
*Presenter: [email protected] Heat, Light, and Sound Research, San Diego, U.S.A.
2 Woods Hole Oceanographic Institution, Woods Hole, U.S.A.
ABSTRACT
Refraction and reflection in the latitude/longitude direction (as well as depth) affect
sound propagation in certain environments. Nonlinear internal waves are an example
of an oceanographic feature that can produce dramatic effects. Seamounts and
continental slopes are examples of bathymetric features that can also matter. Still
stronger features can be found in constrained spaces such as harbors; such an
environment with its many reflecting boundaries scarcely resembles an open ocean
scenario, which is often modeled as a cylindrically symmetric medium. One anticipates
big effects as the sound rays bounce off both the bottom and the sidewalls --- it is more
like a problem in architectural acoustics.
To understand better these effects and to verify our capability to model them, we
have begun an experimental program in which a variety of environments are being
studied. The talk will report on the first site, which was in the old Quincy Shipyard of
the Weymouth Fore River. The experiment was conducted on May 25, 2018 and as of
this writing is still being analyzed. An extremely detailed bathymetric survey was done
using an autonomous surface vehicle called a Jetyak. The Jetyak was also used to tow
an acoustic source that was complemented by a source towed by another vessel. Chirps
covering the 8-34 kHz band were used to measure the impulse response of the channel.
The key initial questions for this site: 1) are 3D effects important? 2) can we model
them effectively? The acoustic modeling is being done with the BELLHOP3D beam-
tracing code that has evolved in recent years into a fairly mature model. There are few
alternatives as most ocean acoustic models assume outgoing waves and therefore
cannot treat the reflections. We will discuss our conclusions in this presentation.
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The 6th Pacific Rim Underwater Acoustic Conference
Underwater Acoustic Sensor Array Processing: Problems and Improving Approaches
Yuanliang Ma*, Yixin Yang, and Yong Wang
*Presenter: [email protected]
School of Marine Science and Technology, Northwestern Polytechnical University,
Xi’an 710072, China
ABSTRACT
Problems and improving approaches for underwater acoustic sensor array
processing are presented based on recent progress made in our research group. The
problems concern about precise analytic solutions for arbitrarily configured arrays, high
gain processing for arrays with limited size at low frequencies, wideband requirement
and ultra-low side-lobe design of beampattern, in addition to a new concept on adaptive
arrays in changeable noise environments.
A unified framework is given in this talk by providing the theoretical solution for
arbitrarily configured sensor arrays. Supposing the noise covariance matrix is obtained,
it is feasible to decompose it into orthogonal mode vectors through Gram-Schmidt
Transform. A matrix form of the transform is deduced which facilitates to express the
inverse of the covariance matrix in an analytic form. Based on these, a series of
expressions are obtained namely the solution of optimal array weighting vector, the
optimal beam-pattern for maximum array gain, the robustness analysis of the optimal
solution etc. All above solutions are expressed in closed-form and the information
required a priori is the environmental noise covariance matrix as well as the direction
vectors of the receiving array in hand.
Following the theoretical framework above, it is feasible to find specific methods
for the mentioned problems. That is: Mode Decomposition and Synthesis method for
arbitrarily configured sensor arrays, theoretical and practical solutions for Super-
directivity, beam-pattern Side-lobe Control in mode space, Wideband Implementation
of optimal array processing, in addition to Feed-forward Adaptation to array processing
for changeable underwater acoustic environments. Tremendous computations and
simulations have been conducted together with typical array design experiments, which
confirm the merits of the solutions and technical approaches.
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The 6th Pacific Rim Underwater Acoustic Conference
Radial Velocity Estimation of Moving Source Using Pressure Difference of Dual Hydrophones
Ruijie Meng1,2, Shihong Zhou1, *Fenghua Li1
*Presenter: [email protected] 1 State Key Laboratory of Acoustics, Institute of Acoustics,
Chinese Academy of Sciences, Beijing, 100190, China 2 University of Chinese Academy of Sciences, Beijing 100049, China
ABSTRACT
Motion velocity estimation of a moving source is very important for marine
application of common interests. This paper presents an approach to estimate the radial
velocity of moving source using dual hydrophones. The radial separation of the dual
hydrophones is required to satisfy less than one-fourth of wavelength. The enough
range or time accumulated window due to tonal source or receiver motion is also
needed. In this approach, the particle vibration velocity could be calculated according
to the pressure difference principle with the known source azimuth. The wavenumber
spectrum of normal modes can be obtained using Hankel transform from the pressure
field and the particle vibration velocity, respectively. From the ratios of their peak
amplitudes corresponding to the separated normal mode, the source radial velocity
could be estimated through the relationship between the theoretical and hypothetical
wavenumbers. Simulations show that the relative error of radial velocity estimation is
less than 10% when the SNR is greater than 0 dB. Using the data from the SWellEx’96
sea trial in the sea area of San Diego in California conducted by University of
California, the estimated radial velocities of the moving source match the real values
from GPS measurement.
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The 6th Pacific Rim Underwater Acoustic Conference
A Model-free Approach for Inverting the Intrinsic Attenuation α(f) of Sea-bed Sediment
*Z.D. Zhao, J. Zeng, L. Ma and E.C. Shang
*Presenter: [email protected]
Key laboratory of underwater acoustics environment, Institute of Acoustics, CAS,
China
ABSTRACT
Inverting the sea-bed geoacoustic (GA) properties from measurements of ocean
acoustic field has been a very active research area in the past four decades, of which the
most difficult part consists in the attenuation α(f) and its frequency dependency. So far,
most of the inverting results are obtained from model-based approach, i.e. a GA bottom
model needs to be assumed afore, which may lead to critical distortion of α(f) due to
model-mismatching. In order to overcome the model-mismatching problem and to
invert the intrinsic α(f), we propose a model-free approach depending on the
perturbation-based integral expression of modal attenuation βm(f). The model-free
reflective phase-shifting parameter P(f) of the bottom as a priori information combined
with WKB approximation of the modal function ψm(z) make the whole integrand
known. Sensitivity analysis and numerical calculation show that an accurate enough
estimation of the intrinsic attenuation α(f) can be obtained. Preliminary experimental
result at site-B of Yellow Sea (2018) is reported, and in the frequency band of 100-
1000Hz, the inverted α(f) clearly reveals a nearly linear frequency dependency.
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The 6th Pacific Rim Underwater Acoustic Conference
Deconvolved Conventional Beamforming Applied to the SW06 and SWellEx96 Data
*T. C. Yang, S. H. Huang
*Presenter: [email protected]
Ocean College, Zhejiang University, Zhoushan, Zhejiang, China
ABSTRACT
Horizontal arrays are often used to detect/separate a weak signal and estimate its
direction of arrival among many loud interfering sources and ambient noise.
Conventional beamforming (CBF) is robust but suffers from fat beams and high level
sidelobes. High resolution beamforming such as minimum-variance distortionless-
response (MVDR) yields narrow beam widths and low sidelobe levels but is sensitive
to signal mismatch and requires many snapshots of data to estimate the signal
covariance matrix, which can be a problem for a moving source. Deconvolution
algorithm used in image de-blurring was applied to the conventional beam power of a
uniform line array (spaced at half-wavelength) to avoid the instability problems of
common deconvolution methods (T. C. Yang, IEEE J. Oceanic Eng., 43, 160-172,
2018). The deconvolved beam output yields narrow beams, and low sidelobe levels
similar to, or better than MVDR and at the same time retains the robustness of CBF. It
yields a higher output signal-to-noise ratio than MVDR for isotropic noise. The method
is applied to the horizontal array data collected during the SW06 and SWellEx96
experiments. Bearing time record are created to compare the performance of various
beamforming methods.
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The 6th Pacific Rim Underwater Acoustic Conference
A Simple Estimation of the Seabed Sound Speed with the Group Speed of the Critical Mode
*J. Zeng, Z.D. Zhao, L. Ma and E.C. Shang
*Presenter: [email protected]
Key laboratory of underwater acoustics environment, Institute of Acoustics, CAS,
China
ABSTRACT
The critical mode (the mode with the highest order) penetrates into the seabed the
deepest and then is the most sensitive mode to the varying of the seabed geacoustics
parameters (seabed sound speed, density and attenuation). The quantities related to the
critical mode, such as the grazing angle and group speed, have the born advantage in
inverting the seabed geoacoustics parameters. In this paper, a simple method of the
estimation of the seabed sound speed is discussed, which is based on the group speed
of the critical mode. In the Pekeris waveguide, when the frequency is high enough, the
seabed sound speed 𝑐𝑏 has a simple relationship with the water sound speed 𝑐𝑤 and
the group speed of the critical mode 𝑣𝑔𝑀 as 𝑐𝑏 ≈ (𝑐𝑤
2 𝑣𝑔𝑀⁄ ). The seabed sound speed
can be rapidly inferred with the knowledge of 𝑐𝑤 and 𝑣𝑔𝑀. With the warping transform
and the relationship between the warped frequency and the group speed, the group
speed of the critical mode can be directly extracted from the envelope of the warped
spectrum of the broadband signal received at close range. Both the simulation data and
the experimental data collected in January 2018 in Yellow sea of China are used to
testify the inversion. The inverted results are compared to those exploited with MFP
method and core sampling. At lower frequency band (f=100~600Hz), the inverted
sound speed has good agreement with those inverted with MFP, which is between
1570~1600m/s. At higher frequency (f=1200~2500Hz), the inverted sound speed
agrees with core sampling results well, which is between 1530~1550m/s.
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The 6th Pacific Rim Underwater Acoustic Conference
Comparison of Alternative Underwater Communication Modulation Schemes in
Various Conditions
*Gee-Pinn James Too, Li-Hua Hsu, Kuan-Yuan Chen
*Presenter: [email protected]
Department of Systems and Naval Mechatronic Engineering,
National Cheng Kung University, Tainan, Taiwan
ABSTRACT
Underwater acoustic communication (UAC) has been widely developed by
researchers. Multipath effects induce severe inter-symbol interference (ISI) in the
communication process. In the present study, three alternative communication
modulation schemes such as : Frequency Shift Keying(FSK),Phase Shift Keying(PSK)
and Orthogonal Frequency Division Multiplexing(OFDM), are used and compared with
Time Reversal Mirror(TRM) and without TRM process. Simulations and experiments
are conducted respectively at various ocean conditions. Simulations are conducted for
shallow water communication and deep sea communication. Experiments are
conducted in the testing platform of 4mX8mX175m towing tank at National Cheng
Kung University. The results indicate that by using TRM enhances SNR by 3 to 5 dB,
therefore it gives better communication, particularly for shallow communication. If
multipath effects cannot be avoided, FSK gives more consistent communication results
than PSK in shallow water communication. At low SNR condition, PSK gives better
communication than FSK. Finally, OFDM gives the fastest communication rate among
the three modulation schemes. However, OFDM is sensitive to frequency shift and
sampling rate shift.
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The 6th Pacific Rim Underwater Acoustic Conference
An Effective System Modeling Method for the Reduction of Low Frequency Noise from Marine
Detection UUVs
Xiao Chuan MA, *Chao FENG
*Presenter: [email protected] Key Laboratory of Information Technology for AUVs, Institute of Acoustics,
University of Chinese Academy of Sciences, Beijing, China
ABSTRACT
The vibro-acoustics and modal analysis of the suspension architecture of the power system in an unmanned underwater vehicle, which is used for the researches of oceanography and marine life, are studied in this paper. The sensors carried on board for underwater acoustic detection and exploration requires strictly controlled noise level, and the self-induced noise and vibration of the UUV mainly come from the power and propulsion system. Due to the complicated undersea environment, a UUV with variable speed drive is needed. Under the circumstances, the noise level could escalate with the speeding up.
An effective noise and vibration control scheme can remarkably reduce the
radiation noise. However, the solution to the suspension architecture for the power system is usually difficult due to its component complexity. An efficient analysis method is the key to the selection of appropriate suspension architecture. The experimental method tends to be costly and time consuming. Subsystem simulations for each component is feasible, yet usually fail to meet expectations when applied to the whole system. A full system modeling method is adopted to examine the natural frequencies and mode shapes of the power system and to determine a material parameter optimized suspension scheme.
In the proposed method, the power and propulsion system is analyzed using finite element model and the suspension architecture is modeled using spring-damper elements, which will suffice to illustrate the low frequency vibro-acoustical analysis. Through the proposed full system modeling, the connection between the suspension architecture and the radiated noise is established. The operating noise is inevitable, however, the optimized suspension scheme acquired through the proposed method is proved by the experimental results to be capable of keeping the system noise at a low level for all the possible working conditions of the UUV.
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The 6th Pacific Rim Underwater Acoustic Conference
2016 Shallow-Water Experiment on Ocean Acoustic-Dynamic Coupled Data Assimilation in
South China Sea
*Wen Xu, Jianlong Li
*Presenter: [email protected]
School of Information Science and Electronic Engineering
Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province
Zhejiang University, China
ABSTRACT
Ocean acoustic-dynamic coupled observation can improve the prediction accuracy
of the acoustical and oceanographic fields by assimilating the observation data such as
sound pressure, water temperature, and salinity. Such a system was integrated jointly
by Zhejiang University, Institute of Acoustics - Chinese Academy of Sciences, China
Shipbuilding Industry Corporation, Harbin Engineering University, and the Ocean
University of China. The system includes seven fixed moorings, two autonomous
underwater vehicles, and an onshore communication and data center, which involves
observations of ocean dynamical processes of different time-spatial scales and physical
mechanisms, both scalar and vector acoustical field measurements, networking based
on RF and acoustic communications, acoustic and oceanographic modeling, and data
and model integration. From May to July, 2016, a field experiment was conducted in
the northwest part of the South China Sea, with water depth of about 100 meters. The
experimental site was characterized by persistent internal tidal waves. On-site
forecasting of ocean temperature, salinity, current velocity, and acoustic pressure was
demonstrated for an area of over 60 Km by 60 Km based on the ROMS regional model.
In addition, as probably the first in the world, an acoustic temperature profiler was
installed on a surface ship and showed superior performance in tracking water-column
sound speed variation. The experiment and some preliminary data processing results
are introduced in this talk. Subsequent analyses of the acoustic and oceanographic
synchronously sampled data are expected to generate important scientific significances
of interdisciplinary research.
[Work supported by National High-Tech Program of China under Grant #
2012AA090901]
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The 6th Pacific Rim Underwater Acoustic Conference
A Range-estimation Method for Surface Sources Based on the Characteristic of Bottom Bounced
Sound in Deep Water
*Yan Zhang and Shihong Zhou
*Presenter: [email protected]
State Key Laboratory of Acoustics, Institute of Acoustics,
Chinese Academy of Sciences, Beijing 100190, China
ABSTRACT
The rays of bottom bounced sound in deep water arrive at the receiver through the
paths hitting the bottom boundary once. It is indicated by theoretical analysis and
numerical simulation that due to the interference of multipath rays the intensity of
bottom bounced sound periodically oscillates in the frequency domain at a certain
source-receiver-range. The oscillating period is corresponding to arrival time delays of
rays and the delay time decreases with source-receiver-range increasing. Base on this
characteristic, a range-estimation method for surface sources has been presented. The
results of experimental data processing show that the range of surface sources can be
estimated effectively with a mean absolute error less than 2 kilometers.
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The 6th Pacific Rim Underwater Acoustic Conference
Sound Propagation in Deep Water with a Sloping Bottom
*Zhenglin Li, Renhe Zhang, and Zhiguo Hu
*Presenter: [email protected]
State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of
Sciences, Beijing 100190, China
ABSTRACT
Variation of water depth have large effects on the sound propagation. It is
meaningful for SONAR application to understand the mechanism of sound propagation
in a deep water environment with complex bathymetries. An acoustic propagation
experiment for two different tracks with the flat bottom and the sloping bottom
environments was conducted in the South China Sea. The experimental results show
that the transmission losses (TLs) decrease up to about 5 dB above the slope due the
reflection of the bottom. When a sea hill with height less than 1/10 of water depth exists
at the range of sound beams incident on bottom first time, an inverted-triangle shadow
zone appears at its reflection area. The TLs increase up to 8 dB in the corresponding
area of the first shadow zone, and the abnormal TLs effects can reach to maximal depth
of 1500m. The spatial correlations for the two propagation tracks are also investigated.
The differences of the TLs and the horizontal-longitudinal correlations oscillation
patterns are explained by using the ray theory. [Work supported by the National Natural
Science Foundation of China under Grant No. 10434012 and Grant No. 41561144006]
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The 6th Pacific Rim Underwater Acoustic Conference
Full Wavefield Computation and Propagation Simulations in Typical Irregular Seabottom
Environment
*Shuyuan Du, Shihong Zhou, Yubo Qi
*Presenter: [email protected]
State Key Laboratory of Acoustics, Institute of Acoustics,
Chinese Academy of Sciences, Beijing 100190, China
ABSTRACT
The calculation and prediction of the ocean acoustic field is the basis for
underwater applications in the marine environment. With the development of acoustics
towards low even very low frequency, it is of important theoretical and realistic
importance to calculate accurately the full-wavefield including underwater acoustics
and low-frequency seismoacoustics due to effects of elastic bottoms. This paper focuses
on clarifying the propagation mechanism of low-frequency seismoacoustics. Several
high-precision calculations of the full-wavefield in typical irregular seabottom
environment such as fluctuated layered elastic bottom, slope layered elastic seabottom,
deep sea environment with seamounts are performed. In order to get accurate results,
model mesh and grid optimization to improve the stability of spectral element method
(SEM) are performed. The excitation and propagation mechanism of seismoacoustic,
including body waves, interface wave, etc. are simulated in typical submarine
environments.
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The 6th Pacific Rim Underwater Acoustic Conference
An Improved Non-uniform Norm Method for Sparse Channel Estimation
*Fei-Yun Wu, Kun-de Yang, Rui Duan, Hui Li
*Presenter: [email protected]
School of Marine Science and Technology, Northwestern Polytechnical University,
Xi'an, Shaanxi, China
ABSTRACT
The non-uniform norm (NN) based method exhibits its superiority such as low
computational cost and effective recovery. However, the optimization of descent
gradient is zig-zagging with small step sizes towards the minimum, thus leads to
ineffective and slow convergence. In this study, we aim to improve the convergence
rate at least without the loss of accuracy via alleviating the fluctuations of descent
directions. An accelerated strategy termed Accelerated NN (ANN) is proposed for
sparse channel estimation. ANN reuses the previous and current estimates via the
derivation of a Low Pass Filtering (LPF) operation on the noisy gradient. The LPF
filters the original gradient and prevent the large fluctuations of iterative direction
generated by the steepest gradient descent during the adaptation process. Simulations
are provided to verify the superiority and effectiveness of ANN algorithm.
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The 6th Pacific Rim Underwater Acoustic Conference
Bubble Dynamics Near an Interface
*A. O. Maksimov, Yu. A. Polovinka
Presenter: [email protected]
Pacific Oceanological Institute, Far Eastern Branch of
The Russian Academy of Sciences, Vladivostok, 690041, Russia
ABSTRACT
The presence of gas bubbles plays an important role in the generation, scattering
and absorption of sound in a liquid. The applications of gas bubbles are diverse,
including acoustical oceanography and medical and industrial ultrasound. In the oil and
gas industry, bubble monitoring is required for acoustic remote early warnings of
``blow-out'' from offshore installations, detection of leaks from underwater gas
pipelines, and seabed monitoring. Although a great deal is known about bubble
oscillations in unbounded liquids, it is not very clear to what extent these results are
applicable to the dynamics of constrained bubbles. The present study is aimed at
investigation of bubble dynamic in the presence of bounding surfaces. Explicit
dependences of the first oscillation modes and the scattered field on bubble size,
distance to the flat boundary, and physical parameters of contacting media are obtained.
It is shown that, as the distance to the boundary decreases, dipole oscillations acquire
resonance nature and become comparable in amplitude with radial oscillations. Another
example of a confining surface is the presence of the second gas bubble. For a two-
phase flow, the subject of forced oscillations of a pair of bubbles is important because
it controls how bubbles interact with each other. The proposed approach uses a bi-
spherical coordinate system and is limited to a description of a sufficiently long-wave
acoustical field, so that the bubbles are homobaric, and the medium in the vicinity of
the bubbles can be considered incompressible. The choice of a specific coordinate
system allows the authors to take into account the internal symmetry inherent in this
problem and provides a partial summation on only the most important contributions to
the multiple scattering series. A closed form solution was derived for the scattered
acoustic field that determines its parametric dependence on bubbles sizes and the
separation distance.
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The 6th Pacific Rim Underwater Acoustic Conference
Geoacoustic Properties of, and Propagation Anisotropy Induced by, Subaqueous Sand Dunes on
the Upper-slope of the Northeastern South China Sea
*Ching-Sang Chiu 1, Linus Y. S. Chiu 2, Chi-Fang Chen3, Yiing Jang Yang3,
Jiann-Yuh Lou4, Christopher W. Miller1
*Presenter: [email protected] 11Naval Postgraduate School, Monterey, CA, U.S.A.
2National Sun Yat-sen University, Kaohsiung, Taiwan 3National Taiwan University, Taipei, Taiwan 4R.O.C. Naval Academy, Kaohsiung, Taiwan
ABSTRACT
Very large subaqueous sand dunes have been observed on the upper continental
slope of the Northeastern South China Sea. In an effort to map the highly variable
bathymetry and to attain initial information on the geoacoustic properties, a multibeam
echo sounder (MBES) survey, grabbed sediment samples, as well as acoustic
transmissions of a 1-2 kHz and a 4-5 kHz chirp signal repeated from a towed source
that circled a moored hydrophone were carried out in May, 2013. Pertinent
geoacoustic parameters, specifically the compressional wave speed, attenuation and
layer thickness, were first estimated based on a geoacoustic inversion entailing least-
squares fitting of an ensemble of modeled 2-D transmission losses to the measured
losses in the radial sectors that are largely perpendicular to the sand dunes. In a
different and prognostic manner, Biot theory with inputs analyzed from the sediment
samples were also used to independently predict the compressional wave speed and
attenuation. The consistency between the geoacoustic inversion results and the
prognostic Biot-theory results are compared and discussed. Furthermore, with the
measured bathymetry and estimated geoacoustic parameters, the transmission loss as a
function of bearing around the towed circle were calculated using a PE propagation
model. The modeled transmission losses are compared to the measured ones to help
interpret and gain insights into the observed anisotropy of the transmission loss and its
azimuthal variance. (The research was jointly sponsored by the Ministry of Science
and Technology, Taiwan and the Office of Naval Research, USA.)
The 6th Pacific Rim Underwater Acoustic Conference
Underwater Sound Pressure Sensitivity in Three-dimensional Oceanic Environments
Ying-Tsong Lin
Associate Scientist with Tenure
Applied Ocean Physics & Engineering Department
Woods Hole Oceanographic Institution, U.S.A.
ABSTRACT
Underwater sound propagation in the ocean can be influenced jointly by physical
oceanographic processes, marine geological features, sub-bottom geoacoustic structure,
sea surface disturbances, biology distributions, etc.. As a result, the underwater sound
pressure field will have significant temporal and spatial variability. The primary goal
of this study is to develop a numerical scheme to determine the sound pressure
sensitivity in response to variations of index of refraction caused by changes of
environmental conditions. A sensitivity kernel is first derived from a higher-order
parabolic-equation (PE) approximation, yielding a 3D acoustic sensitivity field between
a source and a receiver. The acoustic sensitivity field is in fact connected to ocean
dynamics, and we can establish the connection using the chain rule of calculus. With
the sensitivity kernel technique, we can analyze the spatial distribution and the temporal
evolution of the acoustic sensitivity field in complex oceanic environments. The paper
will present numerical examples of 3D sound propagation in submarine canyons,
continental slopes and nonlinear internal wave fields. Discussions on other
applications of this sound pressure sensitivity kernel will also be provided, including
uncertainty quantification of transmission loss prediction and adjoint models for 3D
acoustic inversions.
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The 6th Pacific Rim Underwater Acoustic Conference
Towards 3D Global Scale Underwater Sound Modeling
*Tiago Oliveira1, Ying-Tsong Lin2
*Presenter: [email protected] Marine Science Institute, National University of Singapore (NUS)
2 Applied Ocean Physics and Engineering Department, Woods Hole Oceanographic
Institution (WHOI), U.S.A.
ABSTRACT
Underwater low-frequency sound can travel great distances in the oceans, and it
can be detected at thousands of kilometers from the source. It is well known that a
variety of geological and physical oceanographic features can cause horizontal
refraction, reflection, and diffraction on global scale sound propagation. In this regard,
three-dimensional underwater sound models are required for accurately predicting
global scale sound propagation. However, solving accurately the long-range sound
propagation for fully 3D environments involves important scientific challenges and still
leads to very high computational costs.
In this work, we apply a 3D sound propagation model using the parabolic equation
(PE) approximation and the split-step Fourier (SSF) to model the sound field triggered
by a Southern Mid-Atlantic Ridge earthquake. As suggested by recorded field data, 3D
broadband simulations show a wide dispersion due to out-of-plane reflection/refraction.
Nevertheless, due to the lack of knowledge on the exact earthquake sound source
function, it becomes challenging to compare broadband model results with available
field data. In this regard, an adaptive back-propagation method will be evaluated for
recovering the source function. Based on the Southern Mid-Atlantic Ridge earthquake
case, a set of recommendations to improve 3D global scale underwater sound modeling
is presented.
The 6th Pacific Rim Underwater Acoustic Conference
Acoustic Propagation Effects of Subaqueous Sand Dune Bedforms in the South China Sea
*Linus Chiu1, Ching-Sang Chiu2, Chi-Fang Chen3, Yiing-Jian Yang3,
Ruey-Chang Wei1, Andrea Chang1
*Presenter: [email protected] National Sun Yat-sen University, Kaohsiung, Taiwan
2Naval Postgraduate School, Monterey, CA, USA 3 National Taiwan University, Taipei, Taiwan
ABSTRACT
In 2001-2010, the researches of ocean acoustics were focused on the effects of
watercolumn variability and smooth sloping bathymetry, and the resulting sound
propagation effects are known well. From 2012, interests are moved to the acoustic
effects induced by large-amplitude sand dunes. Moreover, large-amplitude sand dunes
and sand waves are discovered in the sea area around Taiwan, including the
northeastern South China Sea and the sea area off Taiwan. The amplitude and width of
sand dunes are much larger than acoustic wave length and will have significant impact
on sound propagation. This project is to study the acoustic propagation effects resulted
by various sand dunes. In this talk, international cooperated experiments were reviewed;
the experimental data of subaqueous sand dune field and the acoustic field and
numerical modeling were used to study the acoustic propagation effects. Channel
impulse response and the anisotropy of sound field were analyzed and discussed. [This
research was supported by the Ministry of Science and Technology of Taiwan with
project number MOST 104-2221-E-110-075 及 MOST 105-2221-E-110-050].
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The 6th Pacific Rim Underwater Acoustic Conference
Challenges and Progress in the Study of the Effects of Noise on Marine Life
Douglas Herrod Cato
University of Sydney, Australia
ABSTRACT
The effects of noise of human activities on marine life have been studied for more
than 35 years and there has been substantial progress, but challenges remain for both
the research on noise impacts and the management of operations to minimise these
impacts. This paper will present an overview of the effects of noise on marine life and
management and mitigation procedures, and discuss the challenges remaining. Most of
the work has been directed at marine mammals, particularly whales, but there is
increasing interest in the effects of noise on fish and invertebrates. The paper will also
present some results of a major project on the response of humpback whales to the noise
of seismic air guns used in searching for oil and gas. It will also discuss the challenges
faced, how these were overcome by development of protocols that led to the successful
completion of the four major experiments. It will discuss and what was learnt that might
inform the design and conduct of future experiments on whale behaviour and other
marine animals in general. The project demonstrated the importance of ensuring that
research on the effects of noise on marine life is conducted by teams that include experts
in all the disciplines required, particularly underwater acoustics. It also demonstrated
the need for an adequate sample size of individual animals to be tested, since there is
significant variation among individuals of a species. There is also a need for the
experimental design to be a balance between trials in which the animals are exposed to
the noise source and control trials where there is no noise exposure. Without adequate
control trials, it is difficult to determine whether a behavioural response was due to the
noise exposure or something that the animals would have done anyway. Many previous
studies have fallen short in some or all of these.
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The 6th Pacific Rim Underwater Acoustic Conference
Assessment of Noise Impacts on Marine Organisms
Tomonari Akamatsu
National Research Institute of Fisheries Science,
Fisheries Research and Education Agency, Japan
ABSTRACT
Underwater noise could cause behavioral, physiological and lethal impacts on
marine organisms. However, the responses are highly variable depends on the source
factors, sound propagation, sensitivity of animals, and background noise. By far, no
internationally recognized standard for the assessment of noise impacts is available
although national or regional level guidelines exist. Here key items for noise impact
assessment are listed for further discussion. Source factors such as source level,
frequency characteristics and directionality are possible to be measured, but in actual
case, reliable measurement is no easy. For example, the pile driving or shipping noise
are not point sources. Sound propagation especially in low frequency range at shallow
waters is a challenging theme. Not only oceanographic structure, but also precise
bathymetry and sediment conditions are required to solve sound propagation equations.
Acoustic sensitivity of small odontocetes are well understood but that of other taxa such
as baleen whales, fish and crustaceans are not extensively measured. Not only the sound
pressure, but also the sensitivity for the particle movement is hard to measure in situ.
Background noise level should be measured for long term at the potential impact zone.
Natural background noise level caused by soniferous animals are generally higher in
warm waters comparing with that in cold waters. Masking effect by the ambient noise
should be considered. At least the noise exposure level within the sensitive frequency
range of the animal should be higher when the potential noise impact is assumed.
Natural background noise changes depends on the time in a day, moon cycle and season,
too. Possible criteria for the noise regulation could be location and time dependent
based on extensive underwater sound monitoring at the impact zone. Note that
monitoring both at impact zone and control zone before during and after the
anthropogenic activates is the basic requirement for the impact assessment.
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The 6th Pacific Rim Underwater Acoustic Conference
Silent Winters: Long Term Study of Fish Chorusing and Evidence of Impact of Continual
Shipping Noise on Fishes
*Siddagangaiah Shashidhar, Chi-Fang Chen
*Presenter: [email protected]
Underwater acoustic laboratory, Department of engineering sciences and ocean
engineering, National Taiwan University, R.O.C.
ABSTRACT
Recent deployment of Passive acoustic monitoring (PAM) autonomous recorders
off the Eastern Taiwan has resulted in collection of huge database of underwater
acoustic recordings from year 2014 to present. This has enabled us to quantify the
abundance, behavior, diversity and impact of noise on marine fauna. Here, we have
carried-out long term study of fish chorusing behavior at Changhua and Miaoli regions.
From past studies, it is known that fish chorus exhibit diurnal, nocturnal, seasonal and
lunar periodicity. However, these studies were restricted to short duration monitoring
without any clear species specific conclusion. Here, for the first time. We have shown
the changing behavior of the fish chorus over the varying season. The species of
croakers found at Changhua exhibit dawn and dusk chorusing from April-August, just
the dusk chorus from October-December, and maintain acoustic silence from January-
March. The region Miaoli was affected by continual shipping noise, due to which there
was ~10 dB rise in ambient noise levels and it is observed that these noise levels are
consistently increasing over the years. As a result, at Miaoli, there is a decrease in the
fish chorus intensity and also change in their chorusing pattern. This is the first clear
evidence of impact of long term shipping noise on the fishes.
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The 6th Pacific Rim Underwater Acoustic Conference
Measurements of Pile Driving Noise from Offshore Wind Farm Construction in Southwest
Coast of Korea
*Dong-Gyun Han, Jee Woong Choi, and Jungyul Na
*Presenter: [email protected]
Hanyang university, Korea
ABSTRACT
The interest in wind power generation, as a kind of renewable energy, has been
increasing worldwide. Especially, offshore wind power generation has been developed
as an alternative to onshore windfarm, which is difficult to ensure the high-quality wind
resources and to resolve environmental problems such as landscape damage and
occurrence of noise. Impact pile driving is accompanied by the construction of wind
power generation and it produces an extremely high level of noise which may cause a
negative impact on marine ecosystem, especially, fishes and marine mammals. Thus, it
is important to monitor the noise level of the pile driving noise and to investigate its
propagation characteristics. Underwater noise generated from impact pile driving was
measured as a function of range in the southwest coast of Korea in 2017 and 2018. In
this talk, the measured noise levels will be presented and compared to the modelling
results. The propagation modelling of the impact pile driving noise is carried out using
the range dependent acoustic model (RAM) based on parabolic equation.
The 6th Pacific Rim Underwater Acoustic Conference
Calculating Marine Mammal Harassment Zones from Hydroacoustic Measurements and
Modeling of Pile Driving Operations
*Roberto Racca, Graham Warner, Alexander MacGillivray, Jorge Quijano,
Melanie Austin
*Presenter: [email protected]
JASCO Applied Sciences, Canada
ABSTRACT
Pile driving generates underwater sound at levels that can harass marine mammals
through disturbance and auditory injury. Environmental agencies in many national
governments have adopted criteria of varying complexity to define and estimate
potential for harassment. In 2016, The United States National Marine Fisheries Service
(NMFS) introduced new guidance for assessing potential of noise-induced injury,
moving from thresholds based on sound pressure levels to dual criteria considering both
peak pressure and cumulative sound exposure threshold levels specific to marine
mammal functional hearing groups. Because of the complexity of calculating
harassment zones using the full acoustic estimation framework of the new criteria,
NMFS provides a spreadsheet calculator, with simplified assumptions, that may be used
optionally to approximate the distances at which the impact thresholds are exceeded for
a given activity. This paper discusses, through case studies from operations in Southeast
Alaska, the implications of using three different approaches to estimate the distances to
both the new and old injury criteria and the (unchanged) SPL-based disturbance criteria
for vibratory driving and impact hammering cylindrical piles. In the first approach,
threshold distances were obtained using empirical regressions of sound levels measured
by seabed-mounted recorders at 10 and 1000 m nominal range. In the second, the
distances were obtained using the NMFS spreadsheet calculator. In the third, a finite-
difference pile driving source model was combined with a parabolic equation
propagation model to estimate received levels and distances to the marine mammal
harassment thresholds using the full framework of the NMFS guidance. The
comprehensive modeling foundation of the latter approach enabled to account for the
influence of environmental parameters such as sediment geoacoustics and bathymetric
features on the acoustic footprint of the operation, leading to a substantially closer
match with reference measurements.
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The 6th Pacific Rim Underwater Acoustic Conference
Soundscape in Shallow Water of Dongsha Island, South China Sea
*Pai-Ho Chiu 1, Ruey-Chang Wei 1, Hin-Kiu Mok 1,2, Keryea Soong 2
*Presenter: [email protected] Institute of Undersea Technology, National Sun Yat-sen University, Taiwan
2 Department of Oceanography, National Sun Yat-sen University, Taiwan
ABSTRACT
Soundscape includes all sounds in one landscape, and it is the acoustic description
of a specific environment. Through long-term soundscape monitoring, interactions
between the living organisms and the environment can be more understood. Dongsha
Island is located within the Dongsha Atoll in the South China Sea and is an important
nursery habitat for many fishes and marine invertebrates. Underwater soundscape may
be a cue for larvae and juveniles of species living in the ecosystem to find the way in
the waters around Dongsha Island. To understand the underwater acoustic
characteristics of Dongsha Island, a suitable amount of related environmental and
biological data is needed. In this study, AUSOMS-mini was used to record underwater
sounds from two shallow-water sites (coral restoration area and shipwreck) on Dongsha
Island. According to the recordings, one peak around 3 kHz was observed at coral
restoration area. It seems that the sound pressure level (SPL) varied with tidal period.
It is speculated that certain activity of animals associated with tide emitted this
characteristic frequency. At the shipwreck site, SPL appeared higher than coral
restoration area as at least 15 dB at 1.6 kHz, 3 kHz and 5 kHz with low variation. It is
assumed that snapping shrimps or soniferous fishes made the frequencies as acoustic
characteristics.
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The 6th Pacific Rim Underwater Acoustic Conference
Changes to the Fine-scale Habitat Use in Indo-Pacific Humpback Dolphins in Relation to
Vessel Traffic in Hong Kong SAR
*Matthew Pine1*, Ding Wang2, Lindsay Porter3, Francis Juanes1 Kexiong Wang2
*Presenter: [email protected]
1Department of Biology, University of Victoria, Victoria, British Columbia, Canada 2 Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
3Sea Mammal Research Unit Hong Kong, St Andrews University, Hong Kong
ABSTRACT
Marine mammals depend on underwater sound for critical life processes. Those
processes include, but not limited to, keeping group members together while navigating
turbid waters, communication between family members, locating prey during feeding
and to avoid predators/danger. Their ability to communicate and sense their
environment using sound is therefore linked to the ambient sound environment;
whereby the biologically-important signal must be audible over the background sound
level. Developments within the Pearl River Estuary (PRE) (such as the HKIA Third
Runway Project, the HK-Macau-Zhuhai Bridge construction and Guishan offshore
wind farm construction) are causing ambient sound levels to rise – to the point where
communication between marine mammals can be masked and causing stress. Noise
pollution can therefore degrade marine mammal habitats around Hong Kong (among
other factors) and survey data between 2011 and 2016 shows that Indo-Pacific
humpback dolphins have moved to southwest Lantau waters and the Soko Islands, away
from the construction activity near their previous core-habitat north of Lantau Island.
However, the waters of SW Lantau Island have a high-degree of marine traffic,
particularly high-speed ferries and fishing vessels. The two primary risks to the
dolphins are auditory masking (potentially leading to reduced feeding efficiency) and
dolphin-vessel collisions (leading to serious injury and death). To investigate this risk,
passive acoustic monitoring from seven listening stations around SW Lantau Island and
the Soko Islands was undertaken between October 2016 and September 2017. Over the
calendar year, 4533 marine mammal detections revealed diurnal and seasonal changes
in the dolphins’ habitat use around the area. Changes in foraging behaviours appeared
to follow that of fish choruses, with no correlation to changing presence of vessel traffic.
These data provide valuable insights into how the fine-scale habitat use by dolphins
overlaps with vessel traffic, providing real data that will be used to formulate
conservation plans.
38
POSTERS
Part III
39
The 6th Pacific Rim Underwater Acoustic Conference
Yeon-Seong Choo, Sung-Hoon Byun, Sea-Moon Kim and Keunhwa Lee. Observation of Acoustic Echoes from Aluminum Hollow Sphere Using a Horizontal Line Array.
OBSERVATION OF ACOUSTIC ECHOES FROM ALUMINUM HOLLOW SPHERE USING A HORIZONTAL LINE ARRAY
Yeon-Seong Choo1, Sung-Hoon Byun2, Sea-Moon Kim2 ,and Keunhwa Lee3
1University of Science & Technology (UST) 2Korea Research Institute of Ships & Ocean Engineering (KRISO)3Department of Defense Systems Engineering, Sejong University
1. IntroductionThe features of acoustic scattering from elastic shells can be
an important clue for discrimination between man-made objectsand natural ones. The physics of such features has been studiedtheoretically by several researchers[1-2] and shown to bedetectable using low- or mid-frequency sonars[3].
This study presents the experimental results of observing theacoustic scattering characteristics from an aluminum hollowsphere. We tried to measure the difference when the inside ofthe sphere is filled with air or filled with water using the uniformlinear array with bistatic configuration.
3. Experiment & Signal processing
(a) (b)
(c)
Fig. 2. The experiment setup. Theexperiment was carried out in anopen water tank of 35x20x8m. Thedistance between target with thearray is 2m. (a) Front view, (b) Topview, (c) The photo
Fig. 4. Near-field beamformingsonar images. They show thedifferent scattered strengthaccording to target conditions(a) Water-filled target , (b) Air-filled target, (c) Non-target.
(a) (b)
(c)
Fig. 3. Normalized amplitude of scattered signal vs. frequency and comparison with the elastic shell scattering model of Hickling.
4. Conclusion & DiscussionAcoustic scattering of an aluminum sphere was observed with
the bistatic configuration at frequencies between 1 to 10 kHz. Theresults show that the beamformed image of the sphere isdependent on the fluid inside the sphere and also on the ratio ofacoustic wavelength to the size of the sphere. The peak locationsof the measured scattering signal level show some similaritieswith the theoretical model over 4 kHz (Fig. 3) but the limitedfrequency resolution of the probe signal makes it difficult toevaluate quantitatively. Below 4 kHz, it shows large deviationwith the model which is believed to be caused by the lowtransmit response of the acoustic projector used in theexperiment. We are going to do an additional experiment usingdifferent signals of better frequency resolution and also to applythe time-frequency analysis method for high resolutionlocalization of the scattered signals.
1. R. HICKLING, of echoes from a hollow metallic sphere inwater J. Acoust. Soc. Am., 36, pp.1124-1137 (1964).
2. K. J. DIERCKS and R. HICKLING, from hollow aluminumspheres in water J. Acoust. Soc. Am., 41, pp.380-393 (1967).
3. S. D. Anderson, K. G. Sabra, M. E. Zakharia, and J. Sessarego, -frequency analysis of the bistatic acoustic scattering from a sphericalelastic J. Acoust. Soc. Am., 131, pp.164-173 (2012).
5. Reference
PRUAC 2018 Email : [email protected]
Parameter ValueFrequency 1:0.25:10 kHz
Pulse Length 1msTarget Outer Radius 205mm
Target Thickness 20mmTarget Type Water-filled / Air-filled
2. TheoryAcoustic signals scattered from an elastic shell include the
specular wave scattered from outside of the shell as well as thecircumferential wave which are generated by Lamb wave.Therefore, the scattered signal is varied according to thediameter and the shell thickness of the sphere, and also the fluidproperty inside the sphere.
The acoustic scattering signals were measured from thealuminum sphere filled with water or air. Table 1 shows theprobe signal and target parameters of the experiment. Fig. 3shows the measured scattering signal level for different sphereconditions and compares them with the theoretical modelsuggested by Hickling [1]. As shown in Ref. [2], the soundscattering signals of a water-filled target was shown to havelarger scattering strength than an air-filled target below 10 ka(normalized frequency).
This research was supported by the Endowment Project of Korea Research Institute of Ships and Ocean engineering (PES9410).
Fig. 1. The configuration of acoustic scattering.
Table 1.
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The 6th Pacific Rim Underwater Acoustic Conference
Cheng Jiang, Wen Xu, Jianlong Li and Zhongyue Chen. Temporal-Spatial Aggregation in Underwater Acoustic Passive Detection with A Mobile Node.
The bigger pitch angle, the betterperformance, because there areless spatial coherence along thevertical direction[2][3];When the pitch angle equals to ,the mobile node has the sameperformance as the static node.
• ;• Hz;• Only the numerical results are displayed
in the figure.
More measurements (longer accumulative time) can have a better performance.
• mobile node motions with a pitch angle of ;
• ;• Hz;• Only the numerical results are displayed
in the figure.
Temporal-Spatial Aggregation in Underwater AcousticPassive Detection with A Mobile Node
Cheng Jiang, Wen Xu*, Jianlong Li, and Zhongyue ChenCollege of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China
Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province, Zhoushan, 316021, China*Email: [email protected]
Passive acoustic detection becomes a challenging problem due to both range- anddepth-dependent transmission loss in the ocean environment. This project proposesa passive target detection method that can be used on a mobile node equipped withsingle hydrophone. Simulation results show that in some scenarios, the proposedmethod outperforms the time accumulation accomplished by only a static node.
INTRODUCTION
Consider a binary hypothesis test problem. Let denote the hypothesis that onlyambient noise is received; and denote the hypothesis that a target presents.Hence, the problem can be modeled as
MODELING
And the detecting probability is
where is a vector with elements of 1. is the distribution function. Thedetail of the calculation process can be found in reference [1].For simulation comparison, we define the detecting probability of a two-dimensional region as
SIMULATION RESULTA square area with a length of 6000 meters;
Monte Carlo Runs;An unknown static target appears randomly in the square area with uniformdistribution and 50 meters depth for each Monte Carlo run;The static node locates in the central of the area at 30 m depth, mobile nodestarts motion from the central at 30 m depth in each Monte Carlo run, bothnodes have the same number of measurements;The velocity of mobile node is 0.35 m/sOne measurement per second;Ambient noise at 300 Hz is 57 dB, 1000 Hz is 54 dB;The source level of unknown static target ranges from 104 to 120 dB indifferent Monte Carlo run;Depth of the sea is 93 meters
In 1000 Hz case, mobile nodeoutperforms the static node,because there are more modes inhigh-frequency case;In 300 Hz case, both nodes havesimilar performance.
• Mobile node motions with a pitch angle of ;
• ;• Both nodes have 20 measurements;• Both Monte Carlo (MC) results and
numerical integration (N) results are displayed in the figure;
• mobile node motions with a pitch angle of ;
• ;• Both nodes have 20 measurements;• Depth of the sea is 1500 meters;• Only the numerical results are displayed
in the figure.
• mobile node motions with a pitch angle of ;
• Both nodes have 20 measurements;• Hz;• Only the numerical results are
displayed in the figure.
The mobile node has betterROC performance in bothsource level whenHz;The higher source level, thebetter performance.
[1] Moschopoulos, P. G., & Canada, W. B. (1984). The distribution function of a linear combination of chi-squares. Computers & Mathematics with Applications, 10(4), 383-386.[2] Lianghao, G., Zaixiao, G., & Lixin, W. (2001). Space and time coherence of acoustic field in shallow water. Chinese Physics Letters, 18(10), 1366.[3]Yang, T. C. (2012). Properties of underwater acoustic communication channels in shallow water. Journal of the Acoustical Society of America, 131(1), 129.
REFERENCES
CONCLUSION
In this project, we proposed a passive target detection method using a mobile node.Simulation results show that the proposed method outperforms the approach with a static node in some scenarios, especially when the unknown target source is a high frequency source.
Different from low-frequencyshallow water case, mobile nodeachieves better performance indeep water when dB at300 Hz;
where and is the number of measurements. is the receivedsignal. For a given frequency , the target signal and the ambient noise
are zero-mean Gaussian noises with variance and , respectively.denotes the transmission function which is determined by static target location
, receiver (mobile node) location , signal frequency and the environment.The energy detector is used in the mobile node, which can accumulate the energyof received signal. The equation is
where the is the detection threshold which can be calculated in CFAR case. Ifexceeds , decides ; else, decides .For a mobile node at given frequency , is a linear combination ofindependent central chi-squares variable with different weight
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The 6th Pacific Rim Underwater Acoustic Conference
Donghyeon Kim, Yonghwa Choi, Gihoon Byun, Seongil Cho and Jeasoo Kim, Direction Finding of Snapping Shrimp Based on Δf - k Spectrum.
Direction finding of snapping shrimp based on spectrum
Frequency -wavenumber analysis can be used to estimate the direction of arrival (DOA) [J. Acoust. Soc. Am., 69, 732-737 (1980)]. When the receiver is a sparse array that is not suitable for conventional plane-wave beamforming, it adversely causes aliasing error due to spatial sampling, thus many striation patterns can emerge in domain. In this study, we propose difference frequency -wavenumber
analysis that is motivated by the frequency-difference beamforming [J. Acoust. Soc. Am., 132, 3018-3029 (2012)]. It is found that this approach can mitigate (or eliminate) such aliasing effect, which extends its applicability to the robust DOA estimation. Numerical simulation and experimental results are presented, and a major drawback is discussed. For experimental verification, the proposed algorithm was applied to the snapping shrimp noise observed during SAVEX15 experiment.
Donghyeon Kim1, Yonghwa Choi1, Gihoon Byun2, Seongil Cho3, and Jeasoo Kim1
1Korea Maritime and Ocean University (KMOU),2Scripps Institution of Oceanography (SIO),3Agency for Defense Development (ADD)
• During SAVEX15, a large number of unintended snapping shrimp noise were recorded by the receiving system.• Because the snapping shrimp noise is an impulse signal and the array is too sparse, the angle of snapping shrimp noise can’t be estimated.• We proposed the modified frequency wavenumber spectrum, that is difference frequency-wavenumber spectrum.• By comparing with the results of frequency-difference beamforming, the proposed algorithm was verified.
Abstract
SAVEX15
Song et al., “Underwater sound channel in the northeastern East China Sea,” Ocean
Engineering 147, 370-374 (2017)
Shallow-water Acoustic Variability EXperiment 2015 (SAVEX15)
Raw data (Snapping shrimp signal, SAVEX15)
1494 m/s
VLA
100m
Source (Snapping shrimp)
…
# 1 (23.5 m)
# 16 (79.8 m)
VL
1508 m/s
Spectrogram (# of ch : 8)
47.13 s – 47.18 s
JD15146165100
(dB)(dB)
Conventional beamforming output
Frequency-difference beamforming output
Frequency-difference beamforming output
(Incoherent sum)(Incoherent sum)
(dB)
(dB)
Conventional beamforming output(dB
(dB
Beamforming results (Conventional vs. Frequency-difference method)
Formula derived through frequency-difference beamforming
Frequency-difference beamforming
Frequency-difference component
Difference frequency-wavenumber spectrum
Frequency-difference
beamforming
Difference frequency –
wavenumber spectrum
FFT in spatial domain
spectrum
Data, Spectrum output (Snapping shrimp signal, SAVEX15)
spectrum
spectrum
47.13 s – 47.18 s
(dB)
(dB)
(dB)
Comparison : spectrum vs. Frequency-difference beamforming
(dB) (dB)
spectrum Frequency-difference beamforming
Data analysis
Conclusion
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The 6th Pacific Rim Underwater Acoustic Conference
Sehyun Lee, Keunhwa Lee, Jun-Seok Lim, Myoung-Jun Cheong. Waveform Design for Compressive Sensing Active SONAR.
Waveform Design for Compressive Sensing Active SONAR
1Sehyun Lee, 1Keunhwa Lee, 2Jun-Seok Lim, 3Myoung-Jun Cheong 1Defense Systems Engineering, Sejong University, 2Electronic Information Communication Engineering, Sejong University,
3Agency for Defense Development, Korea
[1] Jindong Zhang, Adaptive Compressed Sensing Radar Oriented Toward Cognitive Detection in Dynamic Sparse Target Scene , IEEE Transactions on Signal Processing [2] Tao Hong, An efficient algorithm for designing projection matrix in compressive sensing
based on alternating optimization Signal Processing Volume 125, August 2016 [3] HAO HE, “Waveform design for active sensing systems-A computational approach”,
University of FLORIDA
Introduction
CS Active SONAR
Results
Conclusion
References
E-mails : [email protected]; [email protected]
2018 The 6th PAIFIC RIM UNDERWATER ACOUSTIC CONFERENCE Taipei/Hualien, Taiwan
Sept 2-5, 2018
Transmission Waveform Optimization
•
Fig 2. The range-Doppler plane of the target scene
•
Fig 3. The result of waveform optimization
Fig 4. Comparison of performances(Hit rate)
•
•
AF of LFM, N=100 AF of Optimized(L), N=100
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The 6th Pacific Rim Underwater Acoustic Conference
Wei-Lun Li, Wei-Yen Chu and Chi-Fang Chen. Dolphin Whistle Detection.
Dolphin Whistle DetectionWei- Lun Li1 ,Wei-Yen Chu1 ,Chi-Fang Chen2
1Master student, Department of engineering Science and Ocean Engineering, National Taiwan University2Professor, Department of engineering Science and Ocean Engineering, National Taiwan University
IntroductionIn the past, research group of marine mammals employed localfishing vessel to approach the activities hot zone of whitedolphins and use the naked eyes to record the appearances ofdolphins. However, this approach is often restricted from theweather and night. To overcome these obstacles, the ultimategoal of this research is to establish an automated monitoringsystem. The PAM (passive acoustic monitoring) system provides asuitable way by placing the underwater recorder SM3M at fiveunder water acoustic station (P1-P5) to record dolphin’s whistle.
2017/04/25-05/18
Methodology
Smoothing
Denoising
Classification
Identification
Smooth Spectrum
• Envelope mean
Remove isolated noise
• Median-Filter
• Band width < 300Hz
• High Continuity in time domain
Automated classification
• Calculate the number ofwhistles.
• Use K-means to classifywhistles.
Result
Detection Ability
• Low False Alarm : 2-8%• Detect various type of whistles• High Accuracy : 90-94%
Constant Frequency
Sine wave & Up sampling
U-Type
Spatiotemporal continuity2017/05/04/16-17
2017/05/04/18-18:30
2017/05/04/18:30-19
2017/05/04/19• Pink color indicates that the dolphins have been
seen in the area.
• Detection range is computed by ASORPS.
• Blue color shows that the dolphins may be in this area
Localization Ability
Design of experiment
• Survey line : triangular, each side is 4km.• Use man-made sound source : chirp signal from 5 to 9 kHz
Use whistle detector to find the chirp signal& compute the correlation coefficient ofcomponents between different recorders.
• Localization median error=50m
• Localization Standard error=44m
Conclusion• We put Whistle-detector into the
practical applications, theexperiments to localize soundsource were done near theKaohsiung Harbor, the average ofthe positioning errors was 50 m.
• Whistle detector can be appliedinto the bio-sound detection &localization.
• The detection range in Miaoli is approximately 1.6~2.2km, because the transmission loss and source level of ambient noise must be considered.
Acknowledgements
Taipei/ Hualien, Taiwan , September 2-5,2018
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The 6th Pacific Rim Underwater Acoustic Conference
Jingyao Liang, Ting Zhang, Wen Xu. Passive Localization Based on Distributed Network via Double-Correlation Function of Opportunity Sources.
Passive Localization Based on Distributed Networkvia Double-Correlation Function of Opportunity Sources
Jingyao Liang, Ting Zhang, Wen Xu*.College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China
Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province, Zhoushan, 316021, China*Email: [email protected]
Double-Correlation Function (DCF) of opportunity sources was first proposed byVerlinden[1] for passive source localization to effectively avoid precise modeling inclassical Matched Field Processing (MFP). Two times correlation have been donebetween sound field of the known source and that of the unknown one, which isactually a generalized MFP. This method in our work is extended into the distributednetwork application, with spatial gain greatly improved. Several kinds of topologicalnetwork are discussed through grating lobe structure and optimal detection range.
DCF via measured data avoids sound field modeling and shows stable localiza-tion performance. Distributed network also provides excellent spatial gain whichcould compensates bandwidth gain. Over three topological structures above, thesquare array has best performance and is suitable for the detection of the target atmoderate distance.
When receiver 1 and 2 are at the same position, is equal to one.
Variable definition• : the field
received at j, emitted from source i atfrequency .
• distance between source i and receiverj, and .
• underwater sound speed.
DCF is intrinsically the beamforming of 2 nodes, so the beampattern at eachfrequency appears different. The higher the frequency is, the more grating lobes thereare.
The grating lobes could be attenuated by averaging over several frequencies,nevertheless, there still exists difficulties when the overlap between known andunknown signal spectrum is not sufficient enough. Distributed network provides aspatial gain which compensates the poor bandwidth gain.
Double-Correlation Function
Averaging over all frequency components of DCF derived from broadband data,the grating lobes (or the side lobes) will be reduced, while the main peak will bereserved and amplified. The localization result is ameliorated with a growth numberof frequencies taken in averaging.
θ=60
4km
4km
2 receivers anchored at bottom
10m
1km
Detected area
Simulation parameters are the same as in reference [1]. Assembling DCF at everygrid generates the ambiguous function of localization.
Three Topological Structures
1km
1km1.5km
The last row of every figure is thenetwork beampattern and others arebeampatterns of every two adjacentnodes.
The square array induces leastgrating lobes at single frequency owingto the diversity of spatial distributionand spatial sampling frequencies.
1km
(a) ULA (b) NULA
(c) Square array
Optimal Detection Range
• Short distance: Uniform lobes, no main lobe appears.• Moderate distance: Dominant main lobes begin to appear even at single
frequency.• Long distance: Similar to plane wave case.
The optimal detection range is about 6-8 kilometers in this configuration.
Network beampattern depends on the distance between source and nodes, wherethe point source and wide area network cause the failure of plane wave hypothesis.
[1] Verlinden, C. (2014). Passive Acoustic Techniques Using Sources of Opportunity (Doctoral dissertation, UC San Diego).[2] Verlinden, C. M. (2017). Acoustic sources of opportunity in the marine environment-Applied to source localization and ocean sensing. University of California, San Diego.
Receivera
b
Source 1 2
Measured data
1st correlation
2nd correlation
nbn
gta
m
) array
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The 6th Pacific Rim Underwater Acoustic Conference
Kuan-Wen Liu and Ching-Jer Huang. Real-time Monitoring of Underwater Sound Using a Buoy Installed with a Hydrophone.
III. Data Analysis Method• Fast Fourier Transform (FFT)
In this study, FFT is applied to convert data fromthe time domain to the frequency domain to obtainfrequency characteristics.• Sound pressure level (SPL)
The method of underwater energy quantification issimilar to the method for calculating the SPL in theair.
where SPL is presented in decibel (dB); is themeasured sound pressure; is the reference soundpressure, which is 10 in water.
• Relation of wave height change – SPL changeOnce the relation between SPL and wave height was
established, the variation in wave height and SPL couldalso be determined for each frequency. In right figure, itis easy to determine the SPL change from the waveheight change once the frequency of interest wasconfirmed. From this figure, the increase of SPL withthe wave height is frequency dependent. Therefore,once the wave height was known, the underwater SPLcould be obtained.
SPL
chan
ge, d
B
Wave height change, cm
SPL,
dB
re 1
Pa
Frequency, Hz
V. Conclusions1. The results of this study show that there was a
relation between SPL and wave height, based onthe analysis of the waves and ambient noisesmonitoring data.
2. SPL increased with an increase in the wave heightfrom 20 to 120 cm.
3. Our monitoring results showed that the increase ofSPL with the wave height is frequency dependent.
II. Experimental Set-up• System integration
The underwater sound monitoring system includeda hydrophone, data logger, computer, and a 4Gnetwork. The data logger used the hydrophone as asound pressure sensor to control the data acquisitionfor three minutes every hour. The data were saved ina computer’s memory card and were calculated aftereach data acquisition. The analyzed data was sent toanother computer through a 4G network.• Installation
A buoy was used as a carrier for the underwatersound monitoring system, a wave height meter, and apower supply in the form of solar panels and batteriesfor all the equipment. The hydrophone with apreamplifier was installed on the buoy about 1 meterbelow the sea surface. The wave height meter wasinstalled at the same height as the water surface. Therest of the equipment, such as batteries, computer,and data logger, among others, are in the hull.• Detection progress
In the normal mode, the data logger stayed asleepbefore warming up, which was two minutes beforethe start of data acquisition every hour, to conservethe battery power. In this mode, the system couldsurvive for months. Furthermore, the event modecould be switched on as needed. The acquisition timecould be then modified remotely.
Real-time monitoring of underwater sound using a buoy installed with a hydrophoneKuan-Wen Liu Ching-Jer Huang
National Cheng Kung UniversityAbstract
This research aims to develop a cost-effectiveunderwater sound monitor to obtain long-term andreal-time underwater ambient noise and its spectrum.The results of this research indicate that a relationbetween wave height and sound pressure level (SPL)was found near the southwestern coast of Taiwan.
IV. Results & Discussions• Relation of SPL – Wave height
Since November 2015, a buoy with real-timeunderwater sound monitoring system was deployed inthe southwestern coast of Taiwan, with a water depth of18 meters. Each sound pressure signal data was firstanalyzed through FFT and then converted to SPL.Then, they were sorted by the wave height to observethe relation between SPL and wave height. It is evidentthat the SPL increased as the function of wave heightonly up to 200 Hz. The more data of wave height, themore phenomena could be observed and discussed.
Shut down
Warming up
Acquire & Save
Send back
2 minutes 3 minutes
Data buoy during deployment
Raspberry pias computer
TermUB as data loggerwith 32GB memory
HTI-94-SSQ as hydrophone
= 10log PI. Introduction
The underwater sound monitor included severalequipment and can be deployed on a buoy. The datacan be used for object detection and surveillance. Inthis research, a relation between wave height andSPL was found. Then, since the wave height meterswere widespread, the changes in wave height wereused to calculate the changes in SPL.
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The 6th Pacific Rim Underwater Acoustic Conference
Raegeun Oh, Bon-Sung Gu, Taek-Lyul Song and Jee Woong Choi. Correction of Bearing Error of Line Array Sonar System Due to Bottom Bounced Path Signal.
Correction of bearing error of line array sonar system due to bottom bounced path signal
, , ,
Hanyang Univ., Republic of Korea Navy
47
The 6th Pacific Rim Underwater Acoustic Conference
Presenters Index
A Akamatsu, Tomonari [email protected] 32
C
Cato, Douglas [email protected] 31
Chapman, Ross [email protected] 12
Chiu, Ching-Sang [email protected] 27
Chiu, Linus [email protected] 30
Chiu, Pai-Ho [email protected] 36
D
Du, Shuyuan [email protected] 24
F
Feng, Chao [email protected] 20
H
Han, Dong-Gyun [email protected] 34
L
Li, Fenghua [email protected] 15
Li, Zhenglin [email protected] 23
Lin, Ying-Tsong [email protected] 28
M
Maksimov, A. O. [email protected] 26
Ma, Yuanliang [email protected] 14
O
Oliveira, Tiago [email protected] 29
P
Pine, Matthew [email protected] 37
Porter, Michael [email protected] 13
48
The 6th Pacific Rim Underwater Acoustic Conference
R
Racca, Roberto [email protected] 35
S
Siddagangaiah Shashidhar [email protected] 33
T
Too, Gee-Pinn James [email protected] 19
W
Wu, Fei-Yun [email protected] 25
X
Xu, Wen [email protected] 21
Y
Yang, T. C. [email protected] 17
Z
Zeng, Juan [email protected] 18
Zhang, Yan [email protected] 22
Zhao, Zhen Dong [email protected] 16
49
The 6th Pacific Rim Underwater Acoustic Conference
Conference Program
September 2 (Sunday)
13:30-14:00 Registration
14:00-16:00 Welcome IceBreaker – Cheer Hall, Cosmos Hotel Taipei
September 3 (Monday)
08:30-09:10 Opening Ceremony Chaired by Chi-Fang Chen
09:10-09:50 Plenary Lecture
Sounds in the Ocean: Experiments and Measurements in
Underwater Acoustics. Ross Norman Chapman
09:50-10:00 Group Photo
10:00-10:20 Coffee Break
10:20-12:00 Session 1 Chaired by Linus Y.S. Chiu
10:20-10:40
1-1 Fully 3D Sound Propagation in the Weymouth Fore River,
with a Dry-Dock and a Ship Hull. Michael Porter, Laurel
J. Henderson, John Peterson, Tim Duda, Arthur Newhall,
Peter Traykovski
10:40-11:00 1-2 Underwater Acoustic Sensor Array Processing: Problems
and Improving Approaches. Yuanliang Ma, Yixin Yang,
Yong Wang
11:00-11:20 1-3 Radial Velocity Estimation of Moving Source Using
Pressure Difference of Dual Hydrophones. Ruijie Meng,
Shihong Zhou, Fenghua Li
11:20-11:40 1-4 A Model-free Approach for Inverting the Intrinsic
Attenuationα(f) of Sea-bed Sediment. Zhen Dong Zhao, J.
Zeng, L. Ma, E. C. Shang
11:40-12:00 1-5 Deconvolved Conventional Beamforming Applied to the
SW06 and SWellEx96 data. T. C. Yang, S. H. Huang
12:00-13:30 Lunch
13:30-15:30 Session 2 Chaired by C. J. Huang
13:30-13:50 2-1 A Simple Estimation of the Seabed Sound Speed with the
Group Speed of the Critical Mode. Juan Zeng, Z.D. Zhao,
L. Ma, E. C. Shang
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The 6th Pacific Rim Underwater Acoustic Conference
13:50-14:10 2-2 Comparison of Alternative Underwater Communication
Modulation Schemes in Various Conditions. Gee-Pinn
James Too, Lin-Hua Hsu, Kuan-Yuan Chen
14:10-14:30 2-3 An Effective System Modeling Method for the Reduction
of Low Frequency Noise from Marine Detection UUVs.
XiaoChuan Ma, Chao Feng
14:30-14:50 2-4 2016 Shallow-Water Experiment on Ocean Acoustic-
Dynamic Coupled Data Assimilation in South China Sea.
Wen Xu, Lianlong Li
14:50-15:10 2-5 A Range-estimation Method for Surface Sources Based
on the Characteristic of Bottom Bounced Sound in Deep
Water. Yan Zhang, Shihong Zhou
15:10-15:30 Coffee Break
Session 3 Chaired by Gee-Pinn James Too
15:30-15:50 3-1 Sound Propagation in Deep Water with a Sloping Bottom.
Zhenglin Li, Renhe Zhang, Zhiguo Hu
15:50-16:10 3-2 Full Wavefield Computation and Propagation
Simulations in Typical Irregular Seabottom Environment.
Shuyuan Du, Shihong Zhou, Yubo Qi
16:10-16:30 3-3 An Improved Non-uniform Norm Method for Sparse
Channel Estimation. Fei-Yun Wu, Kun-de Yang, Rui Duan,
Hui Li
16:30-16:50 3-4 Bubble Dynamics Near an Interface. A.O. Maksimov, Yu
A. Polovinka
09:50-18:30 Poster Session Chaired by Andrea Y.Y. Chang
16:50-18:30 Speed Talk (poster)
18:30-21:00 Poster Award ceremony
Dinner Banquet
September 4 (Tuesday)
Session 4 Chaired by Chung-Wu Wang
08:30-08:50
4-1 Geoacoustic Properties of, and Propagation Anisotropy
Induced by, Subaqueous Sand Dunes on the Upper-slope
of the Northeastern South China Sea. Ching-Sang Chiu,
Linus Y. S. Chiu, Chi-Fang, Chen, Yiing Jang Yang, Jiann-
Yuh Lou, Christopher W. Miller
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The 6th Pacific Rim Underwater Acoustic Conference
08:50-09:10 4-2 Underwater Sound Pressure Sensitivity in Three-
Dimensional Oceanic Environments. Ying-Tsong Lin
09:10-09:30 4-3 Towards 3D Global Scale Underwater Sound Modeling.
Tiago Oliveira, Ying-Tsong Lin
09:30-09:50 4-4 Acoustic Propagation Effects of Subaqueous Sand Dune
Bedforms in the South China Sea. Linus Chiu
10:00-18:00 Local Tour to Taroko National Park
18:00-21:00 Dinner
September 5 (Wednesday)
Plenary Speaker
08:30-09:10 Challenges and Progress in the Study of the Effects of Noise
on Marine Life. Douglas Cato
Session 5 Chaired by Ruey-Chang Wei
09:10-09:30 5-1 Assessment of Noise Impacts on Marine Organisms.
Tomonari Akamatsu
09:30-09:50 5-2 Silent Winters: Long Term Study of Fish Chorusing and
Evidence of Impact of Continual Shipping Noise on
Fishes. Siddagangaiah Shashidhar, Chi-Fang Chen
09:50-10:10 5-3 Measurements of Pile Driving Noise from Offshore Wind
Farm Construction in Southwest Coast of Korea. Dong-
Gyun Han, Jee Woong Choi, Jungyul Na
10:10-10:30 Coffee Break
10:30-10:50
5-4 Calculating Marine Mammal Harassment Zones from
Hydroacoustic Measurements and Modelling of Pile
Driving Operations. Roberto Racca, Graham Warner,
Alexander MacGillivray, Jorge Quijano, Melanie Austin
10:50-11:10 5-5 Soundscape in Shallow Water of Dongsha Island, South
China Sea. Pai-Ho Chiu, Ruey-Chang Wei, Hin-Kiu Mok,
Keryea Soong
11:10-11:30
5-6 Changes to the Fine-scale Habitat Use in Indo-Pacific
Humpback Dolphins in Relation to Vessel Traffic in Hong
Kong SAR. Matthew Pine, Ding Wang, Lindsay Porter,
Francis Juanes, Kexiong Wang
11:30-12:00 Closing Ceremony Chaired by Chi-Fang Chen
Announcement of next PRUAC