Events
Upcoming Event
NICO DECEMBER SEMINAR: Scott Feld, Purdue University "Finding Highly Connected Nodes in Networks: The Power of Common Friends"
Northwestern Institute on Complex Systems (NICO)
11:00 AM
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Lower Level, Chambers Hall
Details
Speaker:
Scott Feld, Professor of Sociology, Purdue University
Title:
Finding Highly Connected Nodes in Networks: The Power of Common Friends
Abstract:
This paper extends the Friendship Paradox – where friends have more friends than random people do, on average – to the more general phenomenon that mutual friends have more friends than friends do, on average. We show that we can find people who who are friends of multiple people in practical sized random samples in one regional Facebook network of 63,392 people with an average of 24 friends each, where people with two friends in a random sample have an average of 212 friends overall, with three friends have an average of 391 friends, etc. We further illustrate this general network phenomenon by taking random samples of citations from 79,034 journal articles. We find that a source cited by two articles in a random sample has an average of 461 citations, placing it in the top 0.01% in numbers of citations among all sources cited by these articles. We provide a general expression for the expected overall number of friends of a person found to have k friends in a random sample from a population with a given distribution of numbers of friends. We show that the effectiveness of using common friends among random samples for finding highly connected nodes is most pronounced when there are nodes with a great disproportion of the ties, as seems to be both typical and important for many types of social and other networks, such as where there are superspreaders of diseases, mega-influencers on the Internet, and highly connected central nodes in centralized neural networks. We discuss further implications, applications, and directions for further research.
Speaker Bio:
Scott Feld served as Assistant to Full Professor of Sociology at the State University of New York at Stony Brook from 1975-1991. He then served as Professor of Sociology at Louisiana State University from 1991 until 2004, and joined the faculty at Purdue University in 2004. He has published over sixty articles, including twelve published in the most prestigious journals in the fields of Sociology and Political Science. His ongoing research interests involve 1) causes and consequences of patterns in social networks, 2) processes of individual and collective decision making, and 3) applications of sociology, most recently including innovations in marriage and divorce laws (covenant marriage). He regularly teaches undergraduate and graduate courses on social networks, research methods, and statistics.
Time
Tuesday, December 3, 2024 at 11:00 AM - 12:00 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
WED@NICO SEMINAR: Lightning Talks w/ Northwestern Scholars!
Northwestern Institute on Complex Systems (NICO)
12:00 PM
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Lower Level, Chambers Hall
Details
Speakers:
Albert Kabanda, PhD Candidate, Earth and Planetary Sciences, Northwestern University
Crustal Structure of the East African Rift System, in Uganda from Receiver Function Analysis
Abstract: We study crustal thickness heterogeneity beneath the western branch of the East African Rift System (EARS) using our temporary seismic array of 19 stations. We apply P-wave receiver function (RF) analysis to our data to estimate crustal thickness and velocity ratios along this part of EARS. Preliminary results from the H–k stacking method show that away from the rift branch the crust is generally 35-40 km thick, which is typical for tectonically stable continental crust. Along the rift the crust is significantly thinner, showing additional along-rift variation. Velocity ratio heterogeneity exists on similar scales.
Neelam Modi, PhD Candidate, Industrial Engineering & Management Sciences, Northwestern University
Modeling the “Who” and “How” of Social Influence in the Adoption of Health Practices
Abstract: Overpopulation in developing countries threatens the economy, environment, food supply, and more. The inadequate utilization of modern contraceptives (MCs) in these regions has prompted extensive exploration of supply-side barriers, but there is a crucial gap in understanding demand-side obstacles, such as personal or partner opposition. Our research addresses this gap by focusing on the sociocultural factors influencing contraceptive decision-making in communities with low modern Contraceptive Prevalence Rates (mCPR). Utilizing the novel Structured Influence Process (SIP) framework, we examine - and quantitatively assess - how an individual's social relations and exposure to persuasive messaging, either in favor of or against MC use, jointly influence their decision to adopt or reject contraceptives.
Maria Warns, PhD Candidate, Engineering Sciences & Applied Mathematics, Northwestern University
Identifiability Analysis of Wastewater Surveillance and Public Health Data
Abstract: Wastewater-based surveillance is an increasingly available data stream which may improve calibration of disease models. Unlike traditional public health measures, wastewater samples reflect the entire population in a sewershed community since individuals infected with SARS-CoV-2 shed viral RNA in their stool regardless of symptomology. But the utility of these measurements to inform models is unknown and depends on both functional characteristics of the chosen disease model and quality of measurements. We compare the utility of wastewater surveillance data with traditional public health data for the calibration of parameters in compartmental disease models using structural and practical identifiability analysis.
Sign Up:
Sign up to present at one of our future Lightning Talk sessions. NICO Lightning Talks are open to graduate students, postdoctoral fellows, and visiting scholars.
Location:
In person: Chambers Hall, 600 Foster Street, Lower Level
Remote option: https://northwestern.zoom.us/j/91878654083
Passcode: NICO24
About the Speaker Series:
Wednesdays@NICO is a vibrant weekly seminar series focusing broadly on the topics of complex systems, data science and network 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, November 20, 2024 at 12:00 PM - 1:00 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
Data Science Nights - November 2024 w/ Stefan Pate, Interdisciplinary Biological Sciences Program
Northwestern Institute on Complex Systems (NICO)
5:15 PM
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Lower Level, Chambers Hall
Details
NOVEMBER MEETING: Tuesday, November 26, 2024 at 5:20pm (US Central)
LOCATION:
In person: Chambers Hall, Lower Level
600 Foster Steet, Evanston Campus
AGENDA:
5:20pm - Meet and Greet
5:30pm - Talk by Stefan Pate, Interdisciplinary Biological Sciences Program
6:15pm - Q&A
SPEAKER:
Stefan Pate, PhD student, Interdisciplinary Biological Sciences Program, Northwestern University
ABSTRACT:
Tapping Underground Enzymatic Functions to Understand and Direct Metabolic Evolution
Characterizing “underground” functions of enzymes will aid our understanding of basic physiology & evolutionary biology, and will expand our bioengineering capabilities. Underground catalytic functions (1) make metabolic networks robust to loss-of-function mutations that compromise major fluxes, (2) figure prominently into hypotheses on the evolution of metabolic diversity, and (3) permit bioengineers to access novel chemistries with a tractable amount of modification to extant amino acid sequences. I'll share work on a machine learning model that predicts unobserved catalytic functions of enzymes, and a method designed to efficiently generate multi-enzyme synthesis networks inclusive of predicted catalytic functions.
DATA SCIENCE NIGHTS are monthly talks on data science techniques or applications, organized by Northwestern University graduate students and scholars. Aspiring, beginning, and advanced data scientists are welcome! For more information: http://bit.ly/nico-dsn
Time
Tuesday, November 26, 2024 at 5:15 PM - 7:00 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)