APL-UW Home

Jobs
About
Campus Map
Contact
Privacy
Intranet

Wu-Jung Lee

Principal Oceanographer

Affiliate Assistant Professor, Electrical + Computer Engineering

Email

leewj@uw.edu

Phone

206-685-3904

Biosketch

I am interested in the use of sound — by both human and animals — to observe and understand the environment. My research spans two primary areas: acoustical oceanography, where I develop and apply active acoustic sensing techniques to infer properties of the ocean interior; and animal echolocation, where I combine experimental and computational approaches to understand the closed-loop sensorimotor feedback in echolocating bats and dolphins. In both areas, I focus on two fundamental aspects for achieving high confidence active acoustic sensing: 1) sampling – what can we do to collect better information? and 2) inference – how do we make reliable interpretation of echo information? Under these overarching themes, I am working to expand acoustic sensing capability for marine ecosystem monitoring at large temporal and spatial scales, and use echolocating animals as biological models to inspire adaptive sampling strategies in an active acoustic context.

Department Affiliation

Acoustics

Education

B.S. Electrical Engineering and Life Sciences, National Taiwan University, 2005

Ph.D. Oceanographic Engineering, Massachusetts Institution of Technology/Woods Hole Oceanographic Institution Joint Program in Applied Ocean Physics and Engineer, 2013

Wu-Jung Lee's Website

https://uw-echospace.github.io/

Videos

Understanding Echoes: A Keynote Lecture at the Acoustical Society of America Meeting

In this keynote lecture to the ASA Meeting in Denver, Lee discusses work with both engineered and biological sonar systems to enable effective extraction and interpretation of information embedded in the echoes. Presented are data-driven methodologies and open-source software tools to tackle challenges imposed by large volumes of echosounder data rapidly accumulating across the global ocean. Lee stresses the pivotal role of collaborations in the emerging field.

More Info

23 May 2022

By sending out sounds and analyzing the returning echoes, both humans and animals use active acoustic sensing systems to probe and understand the environment. High-frequency sonar systems, or echosounders, are the workhorse for observing fish and zooplankton in the ocean. Toothed whales and bats navigate and forage via echolocation in the air and under water. In this talk, I will discuss our work with both engineered and biological sonar systems to enable effective extraction and interpretation of information embedded in the echoes. We are developing data-driven methodologies and open-source software tools to tackle challenges imposed by large volumes of echosounder data rapidly accumulating across the global ocean. Using echolocating toothed whales as a model, we are combining experimental and computational approaches to understand biological processing of echo information. Throughout the talk, I will highlight the pivotal role of collaboration in my professional and personal development, and discuss efforts by colleagues and myself to cultivate a sense of community in our field.

Publications

2000-present and while at APL-UW

Beluga whale (Delphinapterus leucas) acoustic foraging behavior and applications for long term monitoring

Castellote, M., A. Mooney, R. Andrews, S. Deruiter, W.-J. Lee, M. Ferguson, and P. Wade, "Beluga whale (Delphinapterus leucas) acoustic foraging behavior and applications for long term monitoring," PLOS One, 16, doi:10.1371/journal.pone.0260485, 2021.

More Info

30 Nov 2021

Cook Inlet, Alaska, is home to an endangered and declining population of 279 belugas (Delphinapterus leucas). Recovery efforts highlight a paucity of basic ecological knowledge, impeding the correct assessment of threats and the development of recovery actions. In particular, information on diet and foraging habitat is very limited for this population. Passive acoustic monitoring has proven to be an efficient approach to monitor beluga distribution and seasonal occurrence. Identifying acoustic foraging behavior could help address the current gap in information on diet and foraging habitat. To address this conservation challenge, eight belugas from a comparative, healthy population in Bristol Bay, Alaska, were instrumented with a multi-sensor tag (DTAG), a satellite tag, and a stomach temperature transmitter in August 2014 and May 2016. DTAG deployments provided 129.6 hours of data including foraging and social behavioral states. A total of 68 echolocation click trains ending in terminal buzzes were identified during successful prey chasing and capture, as well as during social interactions. Of these, 37 click trains were successfully processed to measure inter-click intervals (ICI) and ICI trend in their buzzing section. Terminal buzzes with short ICI (minimum ICI < 8.98 ms) and consistently decreasing ICI trend (ICI increment range < 1.49 ms) were exclusively associated with feeding behavior. This dual metric was applied to acoustic data from one acoustic mooring within the Cook Inlet beluga critical habitat as an example of the application of detecting feeding in long-term passive acoustic monitoring data. This approach allowed description of the relationship between beluga presence, feeding occurrence, and the timing of spawning runs by different species of anadromous fish. Results reflected a clear preference for the Susitna River delta during eulachon (Thaleichthys pacificus), Chinook (Oncorhynchus tshawytscha), pink (Oncorhynchus gorbuscha), and coho (Oncorhynchus kisutch) salmon spawning run periods, with increased feeding occurrence at the peak of the Chinook and pink salmon runs.

Accelerating marine ecological research using OOI echo sounder data

Lee, W.-J., "Accelerating marine ecological research using OOI echo sounder data," in Ocean Observatories Initiative (OOI) Science Plan: Exciting Science Opportunities Using OOI Data, by OOI Facility Board, Narragansett, RI, 2021, 134 pp.

1 Jan 2021

Compact representation of temporal processes in echosounder time series via matrix decomposition

Lee, W.-J., and V. Staneva, "Compact representation of temporal processes in echosounder time series via matrix decomposition," J. Acoust. Soc. Am., 148, 3429-3442, doi:10.1121/10.0002670, 2020.

More Info

1 Dec 2020

The recent explosion in the availability of echosounder data from diverse ocean platforms has created unprecedented opportunities to observe the marine ecosystems at broad scales. However, the critical lack of methods capable of automatically discovering and summarizing prominent spatio-temporal echogram structures has limited the effective and wider use of these rich datasets. To address this challenge, a data-driven methodology is developed based on matrix decomposition that builds compact representation of long-term echosounder time series using intrinsic features in the data. In a two-stage approach, noisy outliers are first removed from the data by principal component pursuit, then a temporally smooth nonnegative matrix factorization is employed to automatically discover a small number of distinct daily echogram patterns, whose time-varying linear combination (activation) reconstructs the dominant echogram structures. This low-rank representation provides biological information that is more tractable and interpretable than the original data, and is suitable for visualization and systematic analysis with other ocean variables. Unlike existing methods that rely on fixed, handcrafted rules, this unsupervised machine learning approach is well-suited for extracting information from data collected from unfamiliar or rapidly changing ecosystems. This work forms the basis for constructing robust time series analytics for large-scale, acoustics-based biological observation in the ocean.

More Publications

In The News

Echolocation is nature’s built-in sonar. Here’s how it works.

National Geographic, Liz Langley

From beluga whales to bats and even to humans, many animals make sounds that bounce back from objects to help with navigation and hunting.

3 Feb 2021

Big data and fisheries acoustics

ICES (International Council for the Exploration of the Seas) News

Big data is one of the next steps in the evolution of fisheries acoustics. These data provide unprecedented observations of the aquatic environment but with this abundance of data comes the costs of storage, access and discoverability, processing and analysis, and interpretation.

15 Sep 2020

Scientists unravel the ocean's mysteries with cloud computing

UW Information Technology, Elizabeth Sharpe

The OOI Cabled Array is delivering data on a scale that was previously not possible. More than 140 instruments are working simultaneously.

That’s why oceanographers teamed up with data and research computing experts to organize a unique event at the University of Washington in late August 2018 to help ocean scientists learn the computational tools, techniques, data management and analytical skills needed to handle this massive amount of data.

8 Nov 2018

More News Items

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
Close

 

Close