Friday, March 18
3:00 p.m.
Research Hall, Suite 373-381
Tom Dover, PhD Candidate, Computational Social Science Program, Department of Computational and Data Sciences, George Mason University, will speak on: Toward Implementing a Complex Social Simulation of the Offending Process: The promise of a synthetic offender
For upcoming seminars from Computational Social Science, click here
Monday, March 14, 3pm
Krasnow Institute Room 229
Fairfax Campus
How Firing Rate Heterogeneity is Mediated by Intrinsic and Network Heterogeneity
Cheng Ly
Assistant Professor, Statistics & Operations Research Department
Virginia Commonwealth University
Abstract:
Heterogeneity of neural attributes has recently gained a lot of attention and is increasing recognized as a crucial feature in neural processing. Recent experimental recordings in electric fish indicate that the heterogeneous network input can mediate response heterogeneity of superficial pyramidal cells in a cortical area (Marsat Lab, WVU). These data motivated us to theoretically study how heterogeneity of neural attributes in general alter firing rate heterogeneity. We ask how 2 sources of heterogeneity: network (synaptic heterogeneity) and intrinsic heterogeneity alter response heterogeneity.
First we address this in a canonical recurrent spiking network model with random connectivity (Erdos-Renyi graph). The relationship between intrinsic and network heterogeneity can lead to amplification or attenuation of firing rate heterogeneity, and these effects depend on whether the recurrent network is firing asynchronously or rhythmically. We analyze the system and derive compact analytic formulas to precisely describe the phenomena.
Second, we adapt our theory to a delayed feedforward neural network to better model the electric fish system. The theory is used to demonstrate that a feedforward network with structured connectivity rules exhibit qualitatively similar statistics as the experimental data. Specifically, the stimulus tuning of particular cells is related to the network architecture, i.e., the number of synaptic connections. Thus, the model demonstrates that intrinsic and network attributes do not interact in a linear manner but rather in a complex stimulus-dependent fashion to increase or decrease response heterogeneity and thus shape population codes.
This is joint work with Gary Marsat (West Virginia University).
The Krasnow Institute hosts a seminar at 4:00 p.m. each Monday afternoon during the academic year with invited guest speakers presenting on a topic in the cognitive sciences. Click here for upcoming seminars.
We extend congratulations to Jose Manuel Magallanes, Professor of Political Science at the Pontifical Catholic University of Peru in Lima, and former Research Associate at the Center for Social Complexity, who successfully defended his Computational Social Science Ph.D. dissertation on climate change in the Andes, glacial thawing, and human security. Dr. Magallanes is now a Senior Data Science Fellow at the University of Washington in Seattle.
The recent Computational Social Science Society of America conference in Santa Fe attracted participants and audiences from around the world. Among the presenters were Jeff Bassett, member of the Mason-Smithsonian Joint Project on Climate Change and Society, who presented the paper “Evolutionary Computation Applied to Agent-Based Simulation Modeling of Climate and Social Dynamics,” co-authored by Bassett and Dr. Claudio Cioffi, director of the Center for Social Complexity. Also presenting at the conference was Dr. J. Daniel Rogers of the Smithsonian Institution and a member of the Mason-Smithsonian Joint Project. At this same conference, Dr. Robert Axtell, CSS faculty, was the keynote speaker, asking the question: “What Methodology Would Social Scientists Adopt if We Could Start Over?”
Posted 11/17/15
Claudio Cioffi, Joey Harrison, and Meysam Alizadeh, members of the CSC component of the Minerva Project on Radicalization, along with the University of Maryland, the University of Michigan, and the University of Warsaw, presented their work at the 2015 Minerva Meeting and Program in September. At the meeting sponsored by ONR, MASON models drew attention and praise for being at the cutting edge of agent-based simulation research.
Posted 11/12/15
Andrew Crooks was promoted to the rank of Associate Professor of Computational Social Science and Claudio Cioffi was promoted to the special rank of University Professor by action of the Board of Visitors of George Mason University.
Posted 10/28/15
from National Cheng-chi Univerisity (NCCU) in Taipei, Taiwan, and editor of several noted academic journals, visited the Center for Social Complexity recently to discuss the future of collaboration between our respective groups. Possible topics include agent-based and complexity modeling on domains such as computational historical dynamics, disaster modeling and risk analysis, and applications in economics and finance. Dr. Cioffi will visit Dr. Cheng at the new NCCU institute for computational social science in 2016.
Posted 10/26/15
the Global Humanitarian Technology Conference in Seattle October 8-11. This is one of several meetings leading up to his participation in global humanitarian science and technology forums to disseminate the new agent-based model NorthLands of the Mason-Smithsonian Joint Project.
Dr. Claudio Cioffi announced the new MASON NorthLands, an agent-based model of climate change and emergent societal impacts, at the annual conference of the European Social Simulation Association (ESSA), in Groningen, Netherlands, September 14-18. This is the main “federated” model of the Mason=Smithsonian Joint Project on Climate and Society, funded by the Cyber-enabled Discoveries and Innovation (CDI) Program of the the National Science Foundation (NSF).
the joint team on the NorthLands model, will present his research on cultural evolution, building on R. Reynolds’s work with cultural algorithms, at the upcoming workshop on Computational Social Science in Cologne, Germany, this month. Peter also passed his qualifying doctoral exams with flying colors and is now preparing his doctoral dissertation proposal leading to candidacy.
