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Kevin Williams

Interim Executive Director

Associate Professor, Oceanography

Email

williams@apl.washington.edu

Phone

206-543-3949

Biosketch

Kevin Williams' research efforts include theoretical and experimental examination of scattering from, and propagation within, ocean sediments. He is also involved in research on the effects of ocean internal waves on acoustic imaging.

Dr. Williams has been with the Laboratory since 1988 and now serves as a principal physicist and the Chair of the Ocean Acoustics Department. He holds a Ph.D. in physics (Washington State University) and the post of Associate Professor in the UW School of Oceanography.

Department Affiliation

Acoustics

Education

B.S. Physics, Washington State University, 1979

M.S. Physics, Washington State University, 1983

Ph.D. Physics, Washington State University, 1985

Videos

MuST — The Multi-Sensor Towbody System to Detect and Classify Unexploded Ordnance

Munitions, left behind from past military training and weapons testing activities, litter shallow water environments at many hundreds of current and former DoD sites. APL-UW is addressing this munitions remediation problem with the MuST system that uses sonars mounted on a towbody and surface vessel support infrastructure to detect and classify hazards on the seafloor and buried in sediments.

26 Aug 2019

History of Acoustics Research at APL-UW

Six Decades of Acoustics Research at APL-UW.

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5 Oct 2015

Kevin Williams' presentation at the Acoustical Society of America meeting in Pittsburgh, PA, May 2015.

TREX13: Target and Reverberation Experiment 2013

TREX13 is a large-scale, collaborative ocean acoustics experiment supported by both the U.S. Office of Naval Research (ONR) and the Strategic Environmental Research and Development Program (SERDP).

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5 Dec 2013

The experiment will take place in the Gulf of Mexico near Panama City Beach, Forida in the spring of 2013 and will involve researchers from both the United States and Canada.

The two main components of the experiment are:
1. to measure mid-frequency reverberation in a shallow water environment, and
2. to detect and classify unexploded ordnance and mine-like targets on the seafloor using synthetic aperture sonar.

Publications

2000-present and while at APL-UW

Underwater unexploded ordnance (UXO) classification using a matched subspace classifier with adaptive dictionaries

Hall, J.J., M.R. Azimi-Sadjadi, S.G. Karl, Y. Zhao, and K.L. Williams, "Underwater unexploded ordnance (UXO) classification using a matched subspace classifier with adaptive dictionaries," IEEE J. Ocean. Eng., 44, 739-752, doi:10.1109/JOE.2018.2835538, 2019.

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1 Jul 2019

This paper is concerned with the development of a system for the discrimination of military munitions and unexploded ordnance (UXO) in shallow underwater environments. Acoustic color features corresponding to calibrated target strength as a function of frequency and look angle are generated from the raw sonar returns for munition characterization. A matched subspace classifier (MSC) is designed to discriminate between different classes of detected contacts based upon the spectral content of the sonar backscatter. The system is exclusively trained using model-generated sonar data and then tested using the measured Target and Reverberation Experiment 2013 (TREX13) data sets collected from a synthetic aperture sonar system in a relatively low-clutter environment. A new in situ supervised learning method is also developed to incrementally train the MSC using a limited number of labeled samples drawn from the TREX13 data sets. The classification results of the MSC are presented using standard performance metrics, such as receiver operating characteristic curve and confusion matrices.

Overview of midfrequency reverberation data acquired during the Target and Reverberation Experiment 2013

Yang, J., D. Tang, B.T. Hefner, K.L. Williams, and J.R. Preston, "Overview of midfrequency reverberation data acquired during the Target and Reverberation Experiment 2013," IEEE J. Oceanic Eng., 43, 563 - 585, doi:10.1109/JOE.2018.2802578, 2018.

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1 Jul 2018

The Target and Reverberation EXperiment 2013 (TREX13) included a comprehensive reverberation field project in the frequency band of 2–10 kHz, and was carried out off the coast of Panama City, FL, USA, from April 21 to May 17, 2013. A spatially fixed transmit and receive acoustic system was used to measure reverberation over time under diverse environmental conditions, allowing study of reverberation level (RL) dependence on bottom composition, sea surface conditions, and water column properties. Extensive in situ measurements, including a multibeam bathymetric survey, chirp sonar subbottom profiling, gravity/diver cores, sediment sound speed and attenuation, interface roughness, wind-generated sea surface waves, and water column properties, were made to support studies of environmental effects on RL. Beamformed RL data are categorized to facilitate studies emphasizing physical mechanisms of 1) bottom reverberation; 2) sea surface impact; and 3) biological impact. This paper is an overview of RL over the entire sea trial, intending to summarize major observations and provide both a road map and suitable data sets for follow-up efforts on model/data comparisons. Emphasis is placed on the dependence of RL on local geoacoustic properties and sea surface conditions.

Noise background levels and noise event tracking/characterization under the Arctic ice pack: Experiment, data analysis, and modeling

Williams, K.L., M.L. Boyd, A.G. Soloway, E.I. Thorsos, S.G. Kargl, and R.I. Odom, "Noise background levels and noise event tracking/characterization under the Arctic ice pack: Experiment, data analysis, and modeling," IEEE J. Ocean. Eng., 43, 145-159, doi:10.1109/JOE.2017.2677748, 2018.

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1 Jan 2018

In March 2014, an Arctic Line Arrays System (ALAS) was deployed as part of an experiment in the Beaufort Sea (approximate location 72.323 N, 146.490 W). The water depth was greater than 3500 m. The background noise levels in the frequency range from 1 Hz to 25 kHz were measured. The goal was to have a three-dimensional sparse array that would allow determination of the direction of sound sources out to hundreds of kilometers and both direction and range of sound sources out to 1–2 km from the center of the array. ALAS started recording data at 02:12 on March 10, 2014 (UTC). It recorded data nearly continuously at a sample rate of 50 kHz until 11:04 on March 24, 2014. Background noise spectral levels are presented for low and high floe-drift conditions. Tracking/characterization results for ice-cracking events (with signatures typically in the 10–2000-Hz band), including the initiation of an open lead within about 400 m of the array, and one seismic event (with a signature in the 1–40-Hz band) are presented. Results from simple modeling indicate that the signature of a lead formation may be a combination of both previously hypothesized physics and enhanced emissions near the ice plate critical frequency (where the flexural wave speed equals that of the water sound speed). For the seismic event, the T-wave arrival time results indicate that a significant amount of energy coupled to T-wave energy somewhere along the path between the earthquake and ALAS.

More Publications

Inventions

Synthetic Aperture Processing for Down-Looking Sonar Systems

Record of Invention Number: 48984

Kevin Williams, Timothy Marston, Daniel Plotnick

Disclosure

5 Nov 2019

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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