Events
Past Event
WED@NICO SEMINAR: Johan Koskinen, University of Manchester "Modelling large, messy, and sampled network data"
Northwestern Institute on Complex Systems (NICO)
12:00 PM
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Lower Level, Chambers Hall
Details
Title:
Modelling large, messy, and sampled network data – problems and prospects for principled analysis of real social networks
Speaker:
Johan Koskinen - Lecturer in Social Statistics, Cathie Marsh Institute for Social Research, University of Manchester
Talk Abstract:
The social network analysis (SNA) paradigm has proved a powerful and intuitive explanatory perspective that has recently gained new currency under the more general moniker of network science. SNA draws on graph theory and social entities are conceived of as nodes in a graph connected by lines (or edges), representing how people, organisations, countries, etc. are relationally tied. Having a network perspective results in compelling pictures of the social web; insightful summary measures capturing both positions of individuals and properties of the network; as well as the possibility of statistical modelling of how nodes are connected. Here we consider the latter - statistical modelling of the network. In particular we are considering modelling tie-variables using exponential random graph models (ERGM). ERGMs have their origin in statistical mechanics and are intimately related to Markov random fields and the classic Ising and Potts models. For social networks, in contrast to, say, particle spins on a lattice, the modelling often turns out to be much more complicated but also giving rise to richer models. Here we discuss some issues associated with modelling social networks based on empirical data. Among the challenges of this domain are specifying the boundary of the network and accounting for the often partial nature of data. Additionally, seeing as social networks cannot typically be collected automatically (through for example scraping on-line sources), we have to rely on observational data that is often laden with error. Among the opportunities that real social network data offers is that you may explore the full complexity of people’s relations. People are not only tied to other people but also affiliated with organisations, places, and events. We present these different aspects in the context of a number of illustrative datasets where information is collected and collated from different sources.
Speaker Bio:
Johan Koskinen joined the Department of Social Statistics at the University of Manchester in 2011 having previously worked at the Universities of Stockholm, Melbourne and Oxford. Dr Koskinen has contributed extensively to methodological development in social network analysis to enabled innovative applications by several disciplines. He is one of the co-authors of the RSiena statistical network analysis package for longitudinal network analysis and a contributor to the MPnet software package, one of the most commonly used statistical software packages for network analysis. His methodological contributions are often developed in collaboration over substantive research projects with applied researchers and he is active in disseminating best practices through frequent workshops. He has also co-written two books on social network research methods aimed at practitioners. One of them a book on exponential random graph models (Cambridge University Press) that was awarded the 2016 Harrison White Book Award by the American Sociological Association. His current research concentrates on extending current statistical methodology for modelling social interaction to social networks of multiple types of nodes using data collated and collected from different sources
Live Stream:
Time
Wednesday, September 27, 2017 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
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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
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Friday, June 19, 2026
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Independence Day (observed) - University Closed
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Independence Day (observed) - University Closed
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Friday, July 3, 2026
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Fall 2026 Classes Begin
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Fall 2026 Classes Begin
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Wednesday, September 23, 2026
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