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Dr. Gary Bogle presents at Friday’s seminar

The Colloquium on Computational Social Science/Data Sciences Research speaker for Friday, May 03, 2019, will be Gary Bogle, who recently defended his CSS doctoral dissertation. Gary’s talk entitled “Polity Cycling in Great Zimbabwe via Agent-Based Modeling: The Effects of Timing and Magnitude of External Factors,” will begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group: https://www.facebook.com/groups/257383120973297/
For a list of upcoming and previous seminars, please visit: https://cos.gmu.edu/cds/calendar/

NOTE: this is the last seminar for the spring semester; see you in the fall semester!

Abstract: This research explores polity cycling at the site of Great Zimbabwe. It rests on laying out the possibilities that may explain what is seen in the archaeological record in terms of modeling what external factors, operating at specific times and magnitudes. What can cause a rapid rise and decline in the polity? This is explored in terms of attachment that individuals feel towards the small groups of which they are a part of, and the change in this attachment in response to their own resources and the history of success that the group enjoys in conducting collective action. The model presented in this research is based on the Canonical Theory of politogenesis. It is implemented using an agent-based model as this type of model excels at generating macro-level behavior from micro-level decisions.

The input parameters to the model presented here are the collective action frequency (CAF) and environmental effect multiplier. The results show that a prehistoric polity can be modeled to demonstrate a sharp rise and fall in community groups and that the rise and fall emerges from the individual decision-making.

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Dr. Tavazza from Natl Inst of Stds and Tech

The Colloquium on Computational Social Science/Data Science Research speaker for Friday, April 19 will be Francesca Tavazza, Ph.D., National Institute of Standards and Technology, Materials Science and Engineering Division. Dr. Tavazza’s talk entitled “The JARVIS project: Accelerating discovery of materials and validation of models using classical, quantum and machine-learning methods” (abstract below) will begin at 3:00 in the Center for Social Complexity Suite located on the third floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

Please visit https://cos.gmu.edu/cds/calendar/to see list of upcoming seminar speakers.

Abstract: Identifying new materials for technological applications is the goal of the Material Genome Initiative (MGI). As a response, NIST started the JARVIS project, a combination of atomistic databases at the classical and quantum level, and machine learning models. JARVIS-DFT is a collection of physical properties computed using Density Functional theory (DFT) for about 30000 materials. For each material, we determined its heat of formation, conventional and improved DFT bandgaps, dielectric function, elastic, phonon, electronic and transport properties. Statistical analysis of such properties allows to identify novel trends as well as new materials with desirable properties. JARVIS-FF is a database of classically computed properties, designed to facilitate the user in choosing the right classical force field (FF) for their investigation. It uses the LAMMPS code to compute the same property, for the same material, with as many force fields as available (more than 25000 classical force-field). We focused on quantities like relaxed structures, elastic properties, surface energies, vacancy formation energies and phonon vibrations. JARVIS-FF contains these calculations for more than 3000 materials, so that a direct comparison between FF is easily achieved. Lastly, using all the properties in JARVIS-DFT as a training set, and novel descriptors inspired by FF-fitting, we developed machine learning (ML) models for all the properties studied in JARVIS-DFT. This allows to make on the fly predictions, and, therefore, to use ML to pre-screen materials.

Dr. Tavazza’s Short Bio:
Undergraduate degree in Physics in Milan, Italy, 1993 (Universita’ Statale di Milano, Milano, Italy)
Master in Material Science in Milan, Italy, 1996 (Universita’ Statale di Milano, Milano, Italy). Dissertation topic: Tight-binding modeling of Cobalt and Iron Silicides, including fitting of the tight-binding parameters.
PhD in Physics at The University of Georgia, GA, USA in 2003 (PhD. Advisor: Prof. Davis Landau). Dissertation topic: Classical Monte Carlo simulations of Si and Si-Ge compounds under various conditions.
PostDoc at NIST starting in 2003, focusing on Density Functional theory (DFT) modeling of mechanical properties in metals.
Brief hiatus working at the Army Research Laboratory in 2008 for a short time, otherwise at NIST ever since I got there as a postdoc.
Currently: running an atomistic modeling group (both classical and DFT modeling) focused on the investigation of specific, technological relevant materials (TaS2, TaSe2, Bi2MnSe4, for instance) as well as on compiling databases of material properties. My group extensively uses artificial intelligence (AI) tools to accelerate material discovery as well as to build novel force fields (physics-inspired, neuron network-based fitting of Si, Ge, SiGe, AlNi potentials).

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PhD Candidate Melanie Swartz to present

The Colloquium on Computational Social Science/Data Sciences Research speaker for Friday, April 12, 2019, will be Melanie Swartz, Computational Social Science PhD Candidate, Department of Computational and Data Sciences. Melanie’s talk entitled “Emoji Use in Social Media During Events” will begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

For a list of upcoming and previous seminars, please visit: https://cos.gmu.edu/cds/calendar/

Abstract: Emoji in social media add more information than just a pictograph to accompany words or convey emotion. Emoji use related to communication about collective social events can provide additional insight about our collective identity and social interactions. Melanie will be presenting preliminary results and welcomes your feedback of her analysis on emoji use in social media for a number of events ranging from national, religious, protests, marches, celestial events, global scheduled events such as International Women’s Day, and more. We look forward to seeing you in person for an engaging discussion on Friday as this event will not be recorded or live streamed.

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Dr. Cody Buntain to present

The Colloquium on Computational Social Science/Data Sciences Research speaker for Friday, March 08, 2019, will be Cody Buntain, Post Doctoral Researcher with New York University’s Social Media and Political Participation Lab. Dr. Buntain’s talk entitled “#pray4victims: Consistencies In Response to and Automatically Identifying Diverse Information Needs During Disasters on Twitter” is scheduled to begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

This session will be live-streamed on the YouTube channel: https://www.youtube.com/channel/UC7YCR-pBTZ_9865orDNVHNA

For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group: https://www.facebook.com/groups/257383120973297/

For a list of upcoming and previous seminars, please visit: https://cos.gmu.edu/cds/calendar/

Abstract: This talk presents commonalities in response across disasters in online social networks (OSNs) and Twitter specifically.

After presenting an algorithm for extracting vocabularies across disasters, we extract type-specific vocabularies for terrorist attacks, earthquakes, and climate-related disasters between 2012 and 2017.

Within similar disasters, commonalities emerge: terrorism responses reference the “attack” and law enforcement, earthquake responses mention the quake and its magnitude, and climate-related responses include safety and requests for aid.

Across disaster types, tweets regularly mention victims/affected and prayer, consistent with communal coping and social support in crisis aftermath.

Using these disaster-type vocabularies, we study Twitter as an alternate measure for severity, correlating casualties to Twitter volume.

These vocabularies better correlate with casualties than baseline crisis lexica, especially in western countries.

Twitter response and casualties diverge at the extreme, and Twitter response is stronger in Western countries, suggesting perceived severity is driven by additional factors.

These vocabularies also potentially represent disaster-type-specific information needs, which we then roll into a machine learning task for automatically identifying crisis-related information in Twitter data.

Bio: Cody Buntain received his PhD from the Computer Science Department at the University of Maryland and is a postdoctoral researcher with New York University’s Social Media and Political Participation Lab. His primary research areas apply large-scale computational methods to social media and other online content, specifically studying how individuals engage socially and politically and respond to crises and disaster in online spaces. Current problems he is studying include cross-platform information flows, network structures, temporal evolution/politicization of topics, misinformation, polarization, and information quality. Recent publications include papers on influencing credibility assessment in social media, consistencies in social media’s response to crises, the disability community’s use of social networks for political participation, and characterizing gender and direction in online harassment.

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3/1 speaker Dr. Craig Yu, dept of CS,

will present at the Colloquium in Computational Social Science and Computational and Data Sciences Research. Dr. Yu’s talk entitled “Synthesizing Human-centric Architectural Layouts via Affordance Analysis and Crowd Simulations” (abstract below) is scheduled to begin at 2:00 (PLEASE NOTE EARLY START TIME FOR THIS TALK ONLY) in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

This session will be live-streamed on the YouTube channel: https://www.youtube.com/channel/UC7YCR-pBTZ_9865orDNVHNA

For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group: https://www.facebook.com/groups/257383120973297/

For a list of upcoming and previous seminars, please visit: https://cos.gmu.edu/cds/calendar/

Abstract: In this talk, I will discuss the recent progress of my team in devising computational design approaches for automatically generating human-centered architectural layouts for real-world design and virtual reality applications. For example, I will talk about the state-of-the-art procedural modeling techniques for generating large-scale architectural layouts that are optimized with respect to human navigation properties; and techniques for automatically generating interior designs for furnishing indoor scenes with furniture objects. In particular, I will discuss how human intentions and functionality considerations can be employed as the key criteria in generating 3D worlds. I will also discuss how human perceptual data tracked from virtual reality can be employed for creating personalized workspace design and for VR training.

Bio: Craig Yu is an Assistant Professor in the Department of Computer Science at the Volgenau School of Engineering. He works on computer graphics, vision, human-computer interaction, and virtual reality, particularly on AI and data-driven techniques for computational design. Yu obtained his Ph.D. in Computer Science from UCLA in 2013 with an Outstanding Recognition in Research Award. Yu was a visiting scientist at the MIT International Design Center and a visiting scholar at the Stanford Computer Graphics Lab. He is the recipient of the Cisco Outstanding Graduate Research Award, the Award of Excellence from Microsoft Research, the UCLA Dissertation Year Fellowship, and the Sir Edward Youde Memorial Fellowship. His research has been featured by New Scientist, the UCLA Newsletter, and the IEEE Xplore Innovation Spotlight. His lab is supported by the NSF, Microsoft, Google, Nvidia, and Oracle.

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Dr. Samuelson, president and chief scientist

of InfoLogix, Inc., will speak at the Computational Social Science Research Colloquium /Colloquium in Computational and Data Sciences, Friday, February 22. Dr. Samuelson’s talk entitled “Garbage Cans, Lymph Nodes and Cybersecurity: Modeling Organizational Effectiveness” (abstract below) will begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

This session will be live-streamed on the YouTube channel: https://www.youtube.com/channel/UC7YCR-pBTZ_9865orDNVHNA

For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group: https://www.facebook.com/groups/257383120973297/

For a list of upcoming and previous seminars, please visit: https://cos.gmu.edu/cds/calendar/

Abstract: We re-examine and extend the well-known “Garbage Can Model” of Cohen, March and Olsen (1972). They postulated that organizational choice can be well represented by a garbage can into which problems and solutions are thrown randomly. When, by random mixing, a solution meets a problem, the problem is solved and removed from the venue. In 2006, Folcik and Orosz presented an agent-based model of a lymph node, into which blood cells bring foreign substances and objects that are then neutralized by specialized immune system cells. This model led several social scientists, notably Troitzsch (2008), to point out a strong resemblance to the garbage can model, but now adding the recognition that problems require skill sets which some, but not all, solvers possess. Matching skill sets is critical to effective performance, and providing the right mix of solver skill sets enables the organization to perform effectively and economically. We suggest ways to apply this approach to integrated man-machine systems intended to enhance information systems security. One implication is that some approaches currently popular with policy-makers are highly unlikely to work.

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Dr. Robert Axtell to present on 2/15

The Computational Social Science Research Colloquium /Colloquium in Computational and Data Sciences speaker for Friday, February 15, 2019, will be Robert Axtell, Professor, Computational Social Science Program, Department of Computational and Data Sciences, College of Science/Department of Economics, College of Humanities and Social Sciences, George Mason University. Dr. Axtell’s talk entitled “Lifetime/Survival/Reliability/Duration Analysis for Computational Models” will begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

This session will be live-streamed on the YouTube channel: https://www.youtube.com/channel/UC7YCR-pBTZ_9865orDNVHNA

For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group: https://www.facebook.com/groups/257383120973297/

For a list of upcoming and previous seminars, please visit: https://cos.gmu.edu/cds/calendar/

Abstract: In a variety of computational models, structures arise, evolve, then disappear, perhaps replaced by other, comparable structures. For example, in some economic models firms form from the interactions of agents, operate for some period of time, and then exit. In housing models, households hold mortgages for finite periods of time before replacing them either due to refinancing or moving to a new house. In political (marketing) models the interests of parties (businesses) are aligned with certain segments of voters (consumers) for a period of time, until competition leads to realignment (brand switching). In environmental policy models specific polluting technologies have finite lifetimes and are eventually replaced by cleaner technologies. In disease models people are infected for varying lengths of time based on their health status, policies, etc. Traffic jams and conflicts have finite duration.

In this talk I will review the mathematical and statistical formalisms of lifetime analysis, also known as survival analysis in biostatistics and reliability analysis in engineering, focusing on the concepts most useful for computational models. Specifically while the former field has concerned itself with censored data (e.g., short clinical trials during which not all patient health outcomes can be observed), and the latter has focused on schemes to manage unreliable equipment, in computational modeling we often need to better understand both age and lifetime distributions of objects in our models, typically have large amounts of quasi-exhaustive ‘data,’ normally know some covariates, and usually work in discrete time.

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John Schuler will present at CDS Colloquium

The Computational Social Science Research Colloquium /Colloquium in Computational and Data Sciences speaker for Friday, February 08, 2019, will be John Schuler, Ph.D. student in the Department of Economics, George Mason University. John’s talk entitled “Nonparametric Estimation of General Equilibrium Price Vectors” will begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

This session will be live-streamed on the YouTube channel: https://www.youtube.com/channel/UC7YCR-pBTZ_9865orDNVHNA

For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group: https://www.facebook.com/groups/257383120973297/

For a list of upcoming and previous seminars, please visit: https://cos.gmu.edu/cds/calendar/

Abstract: Agent-based economic modeling often requires the determination of an initial equilibrium price vector. Calculating this directly requires algorithms of exponential computational complexity. It is known that a partial equilibrium price can be estimated using a median of trades. This paper explores the possibility of a multivariate generalization of this technique using depth functions as well as alternative methods.

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Dr. Keith Waters to present

at the Computational Social Science Research Colloquium in Computational and Data Sciences on Friday, February 1, 2019. Dr. Waters is with the Schar School of Public Policy at George Mason University. His talk, entitled “Firm Formation and the Regional Allocation of Labor” (abstract below), will begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

This session will be live-streamed on the YouTube channel: https://www.youtube.com/channel/UC7YCR-pBTZ_9865orDNVHNA

For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group: https://www.facebook.com/groups/257383120973297/

For a list of upcoming and previous seminars, please visit: https://cos.gmu.edu/cds/calendar/

Abstract: The distribution of city-sizes within countries tends to follow a Pareto distribution that satisfies Zipf’s law. Geographically, larger cities tend to be located more distant from one another than smaller cities. Working towards an explanation of these empirical observations, a geographic extension of Axtell’s agent-based model of endogenous firm formation is presented. The model introduces three components into the underlying model: migration costs, an urban productivity premium, and an urban congestion cost.

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Annetta Burger to present at CDS colloquium

The Computational Social Science Research Colloquium /Colloquium in Computational and Data Sciences speaker for Friday, January 25, 2019, will be Annetta Burger. Annetta Burger’s talk entitled “Operationalizing Resiliency in Complex Adaptive Systems: an Agent-Based Model of a NWMD Detonation” (abstract below) will begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

This session will be live-streamed on the YouTube channel: https://www.youtube.com/channel/UC7YCR-pBTZ_9865orDNVHNA
For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group: https://www.facebook.com/groups/257383120973297/
For a list of upcoming and previous seminars, please visit: https://cos.gmu.edu/cds/calendar/

Abstract: Increasingly, Agent-Based Models (ABMs) are being used to study human behavior in complex adaptive systems. In the process of simulating these systems modelers are faced with a myriad of design decisions regarding the representation of actors and processes necessary for real-world validity. Modelers must make assumptions, reduce a multitude of heterogenous variables and interacting processes into a limited set for simulation and analysis, and fit them into computational frameworks; balancing tradeoffs between simplicity, model accuracy, and computational tractability. Ultimately, the simulation product must provide accurate measures for verification and validation and sufficient transparency for model analysis and understandability to demonstrate the accuracy of the system representation and its predictive power. An ABM of the detonation of a Nuclear Weapon of Mass Destructions provides a case example of how to operationalize human behavior in an ABM for simulation and experimentation.