Events
Past Event
WED@NICO SEMINAR: Sourav Medya, Northwestern University "Optimization and Learning on Graphs"
Northwestern Institute on Complex Systems (NICO)
12:00 PM
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Lower Level, Chambers Hall
Details
Speaker:
Sourav Medya - Research Assistant Professor, Kellogg School of Management, Northwestern University
Title:
Optimization and Learning on Graphs
Abstract:
Networks (or graphs) are a powerful tool to model complex systems such as social networks, transportation networks, and the Web. The accurate modeling of such systems enables us to improve infrastructure, reduce conflicts in social media, and make better decisions in high-stakes settings. However, as graphs are highly combinatorial structures, these optimization and learning tasks require the design of efficient algorithms.
In this talk, I will describe three research directions in the context of network data. First, I will overview several combinatorial problems for graph optimization that I have addressed using classical approaches such as approximate and randomized algorithms. The second part will focus on a different and a more recent approach to solving combinatorial problems by leveraging the power of machine learning. More specifically, I will show how combining neural architectures on graphs with reinforcement learning solves popular data ming problems such as the influence maximization problem. In the last one, I will demonstrate how to deploy these methods on problems in computational social science with applications in decision-making for patent review systems and the stock market.
Speaker Bio:
Sourav Medya is a research assistant professor in the Kellogg School of Management at Northwestern University. He is also affiliated with the Northwestern Institute of Complex Systems. He has received his Ph.D. in Computer Science at the University of California, Santa Barbara. Sourav's research is focused on the problems at the intersection of graphs and machine learning. More specifically he designs data science tools that optimize graph-based processes and improve quality as well as scalability of traditional graph combinatorial and mining problems. He also deploys these tools to solve problems in the interdisciplinary area of computational social science especially to improve innovation.
Location:
In person: Chambers Hall, 600 Foster Street, Lower Level
Remote option: https://northwestern.zoom.us/j/96305319949
Passcode: NICO2022
About the Speaker Series:
Wednesdays@NICO is a vibrant weekly seminar series focusing broadly on the topics of complex systems and data science. It brings together attendees ranging from graduate students to senior faculty who span all of the schools across Northwestern, from applied math to sociology to biology and every discipline in-between. Please visit: https://bit.ly/WedatNICO for information on future speakers.
Time
Wednesday, April 13, 2022 at 12:00 PM - 1:00 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
Data Science Nights - MAY 2026 - Speaker: Xudong Tang, Computer Science and NICO
Northwestern Institute on Complex Systems (NICO)
5:30 PM
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M416, Technological Institute
Details
MAY MEETING: Thursday, May 28, 2026 at 5:30pm (US Central)
LOCATION:
ESAM Conference Room, Tech M416
2145 Sheridan Road, Evanston, IL 60208
AGENDA:
5:30pm - Meet and greet with refreshments
6:00pm - Talk with Xudong Tang, PhD Student, Computer Science, NICO, and the Human-AI Collaboration Lab, Northwestern University
TALK TITLE:
Human and Machine Perception of Voice Similarity
ABSTRACT:
Modern voice cloning systems generate synthetic speech that listeners frequently cannot identify as being synthetic. But a voice can sound natural without sounding like the intended person, and what determines whether a clone is heard as a particular person is an open question. Here we report a large-scale preregistered experiment in which we collected 92,239 responses from 175 participants on their perception of pairs of real recordings, voice clones, and continuously morphed voices drawn from 100 contemporary celebrities across 20 speaker groups. We find that voice clones do not reliably preserve perceived speaker identity, reducing same-speaker judgments by 12.7 percentage points even though the clones are produced by a state-of-the-art text-to-speech model, while leaving different-speaker judgments unchanged. Using continuously morphed stimuli, we find that speakers vary substantially in how much variation their perceived identity tolerates, and that this variation is not predicted by speaker demographics. Speaker embeddings account for 58.9\% (95\% CI = [55.7, 61.9]) of variance in identity judgments, which is more than acoustic features, social attributes, and clone status combined. Once all these observed features are accounted for, clone status adds no additional predictive power. These results shows that the perceptual impact of voice cloning is positional rather than categorical: we can model how listeners judge a voice by how close it falls to the perceptual boundary that defines each speaker's recognizable voice, applying the same criterion to real and synthetic speech alike.
DATA SCIENCE NIGHTS are monthly meetings featuring presentations and discussions about data-driven science and complex systems, organized by Northwestern University graduate students and scholars. Students and researchers of all levels are welcome! For more information: http://bit.ly/nico-dsn
FUTURE DATES:
Data Science Nights will return in September!
Time
Thursday, May 28, 2026 at 5:30 PM - 7:00 PM
Location
M416, Technological Institute Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
Spring 2026 Commencement
University Academic Calendar
All Day
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Spring 2026 Commencement
Time
Sunday, June 14, 2026
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Juneteenth - University Closed
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Juneteenth - University Closed
Time
Friday, June 19, 2026
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Independence Day (observed) - University Closed
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Independence Day (observed) - University Closed
Time
Friday, July 3, 2026
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Fall 2026 Classes Begin
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Fall 2026 Classes Begin
Time
Wednesday, September 23, 2026
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