The Computational Social Science Society of the Americas

CSSSA Webinar Series

[CSSSA Webinar] Economics and Finance Agent-Based Models with Prof. Axtell and Prof. Farmer

Kathleen Salazar-Serna discussing “Modeling Urban Transport Choices with Agent-based Modeling” in our 2025 CSSSA webinar series.
Deciphering travel behavior and mode choices is a critical aspect of effective urban transportation system management, particularly in developing countries where unique socio-economic and cultural conditions complicate decision-making. This presentation introduces an agent-based simulation model designed to understand urban commuters' mode choices and evaluate the impacts of transport policies promoting sustainable mobility. With a focus on developing countries, where utilitarian travel heavily relies on motorcycles, the model incorporates sociocultural factors and social network influences that shape transport behavior. The model parameterization is based on comprehensive survey data collected from a Colombian city, providing essential sociocultural insights into commuter decision-making patterns. Policy simulations reveal positive responses to interventions such as fare-free public transportation, increased bus frequency, and enhanced security measures, albeit with modest shifts in mode choice. This data-driven approach provides a robust analytical tool for examining transport challenges and policy interventions, offering evidence-based insights for policymakers. The model's outputs can be extended to cities with similar sociocultural characteristics and transport dynamics, while the methodology can be replicated across different regions worldwide. The simulation model serves as a testbed for evaluating the effectiveness of transport policies while accounting for local sociocultural dynamics and social network influences on commuter decision-making
Short bio
Kathleen Salazar-Serna is an assistant professor in the Department of Civil and Industrial Engineering at Pontificia Universidad Javeriana in Cali, Colombia. Her current research interests focus on sustainability issues and transport policy analysis. She uses agent-based modeling and network analysis to study transport dynamics.

[csssa webinar] Modeling Urban Transport Choices with Agent-based Modeling

Dr. Matt Koehler and Dr. Emmet Beeker are interviewed by Dr. Andy Collins about the application of Agent-based Modeling to the defense industry. This is the first in our new discussion format were we ask experts about the application of Agent-based Modeling to their domain.

[CSSSA Webinar] Defense Agent-based Models by Dr. Koehler and Dr. Beeker

Dr. Ruth Schmidt discussing emerging approaches to systems-level behavioral challenges at the 2024 CSSSA conference in Santa Fe, NM.

[CSSSA2024 Keynote] Emerging Approaches to Systems-Level Behavioral Challenges by Dr. Ruth Schmidt

Dr. Moore talking about Pretrial Risk Assessment on the Ground at the 2024 CSSSA conference in Santa Fe, NM.

[CSSSA2024 Keynote] Pretrial Risk Assessment on the Ground by Dr. Cris Moore

Drs. Jonathan Ozik & Nick Collier present Distributed Agent-based Simulation with Repast4Py for CSSSA December Webinar.

Abstract:
The increasing availability of high-performance computing (HPC) has accelerated the potential for applying computational simulation to capture ever more granular features of large, complex systems. This talk presents Repast4Py, the newest member of the Repast Suite of agent-based modeling toolkits. Repast4Py is a Python agent-based modeling framework that provides the ability to build large, MPI-distributed agent-based models (ABM) that span multiple processing cores across multiple computing nodes. Simplifying the process of constructing large-scale ABMs, Repast4Py is designed to provide an easier on-ramp for researchers from diverse scientific communities to apply distributed ABM methods. We will present key Repast4Py components and how they are combined to create distributed simulations of different types, building on three example models that implement seven common distributed ABM use cases. We will conclude by illustrating the relationship between model structure and performance considerations, providing guidance on how to leverage Repast4Py features to develop well designed and performant distributed ABMs.

Bios:
Nick Collier is a Senior Software Engineer at Argonne National Laboratory, and Staff Software Engineer in the Consortium for Advanced Science and Engineering at the University of Chicago. As the lead developer for the Repast project for agent-based modeling toolkits and co-developer of the Extreme-scale Model Exploration with Swift (EMEWS) framework, he develops, architects, and implements large-scale agent-based models and frameworks, and large-scale model exploration workflows across various domains.

Jonathan Ozik is a Principal Computational Scientist at Argonne National Laboratory, Senior Scientist with Department of Public Health Sciences affiliation in the Consortium for Advanced Science and Engineering (CASE) at the University of Chicago, and Senior Institute Fellow in the Northwestern Argonne Institute of Science and Engineering (NAISE) at Northwestern University. He is the lead of the Repast project for agent-based modeling toolkits and the Extreme-scale Model Exploration with Swift (EMEWS) framework for large-scale model exploration on high-performance computing resources.

[CSSSA Webinar] Distributed Agent-based Simulation with Repast4Py

We are very excited to host our CSSSA 2024 Best Paper Award Winner Timothy Clancy presenting Micro, Meso, Macro: Generic Structures of Social Complexity for Defense Systems Engineering & National Security Wargames.

Abstract:
Representing micro, meso, and macro sociotechnical systems and the social complexity of populations in national security wargames is a challenge. Prac-titioners need simulation structure at high fidelity, with reliable data, that can fluidly compose and decompose between these levels based on solid the-ory. This paper introduces three recent enhancements to the emerging-state actor model (E-SAM) simulation that can generalized as methodological blueprints for representing sociotechnical systems for system engineers or social complexity for national security wargames. We demonstrate the methods with three experiments. These include recreating the original ISIS case study in Syria & Iraq 2010-2020, a Ukrainian War hypothetical post-conflict stabilization scenario 2022-2032, and a hypothetical humanitarian aid mission after a major natural disaster in Myanmar in 2028. The experi-ments demonstrate the wide versatility of E-SAM and these simulation components to model different patterns of social complexity.
Keywords: Modeling & Simulation, Social Complexity, Sociotechnical

Bio:
Timothy Clancy is an Assistant Research Scientist at START specializing in studying violence and instability as complex systems. This is a second career for Timothy, the first working for IBM as a consultant that led to his deployment as a civilian to Afghanistan supporting counter-roadside bomb efforts. It was in Afghanistan that Timothy first encountered systems thinking and computer simulation methods such as system dynamics capable of mathematically modeling the wicked mess problems he'd encountered throughout his career. This led to a career change after returning from abroad, and Timothy completed his MSc in Simulation Science & Insurgency Dynamics and then a PhD in the System Dynamics of the Lifecycle of Violence and Instability of Non-State actors, both at WPI. Timothy joined the National Consortium for the Study of Terrorism and Responses to Terrorism (START) at the University of Maryland in late 2023. Current research topics include understanding violent radicalization as a system, the terror contagion hypothesis for public mass killings, the emerging-state actor hypothesis for asymmetric and irregular warfare conflicts, and advancing methods for modeling social complexity through computer simulations integrated with AI.

[CSSSA Webinar] Micro, Meso, Macro: Generic Structures of Social Complexity for Defense Systems.

We are very excited to host Matthew Koehler and Andrew Collins presenting Validation of Agent-based Models.

Validation is the process of determining if a model adequately represents the system under study for the model’s intended purpose. Validation is a critical component in building the credibility of a simulation model with its end-users. Effectively conducting validation can be a daunting task for both novice and experienced simulation developers. Further compounding the difficult task of conducting validation is that there is no universally accepted approach for assessing a simulation. These challenges are particularly relevant to the paradigm of Agent-Based Modeling and Simulation (ABMS) because of the complexity found in these models’ mechanisms and in the real-world situations they attempt to represent.
In this presentation, the validation of agent-based models will be introduced, some of the methods and approaches to conducting a validation process will be discussed, and practical tips will be provided. Further to this introduction, a more philosophical discussion about validation will be included. Specifically, a discussion of a new emphasis on thinking about validation in terms of “invalidation.” This philosophical view is hoped to be a starting point for a wider discussion on validation at this year’s CSS annual conference in October. This presentation will be at the introductory level of conducting ABMS validation process but should have something for all experience levels.

Bios:
Dr. Matthew Koehler is computational social scientist at the MITRE Corporation, where he leads the generative social science and computational finance group. During his time at MITRE, Matt has concentrated on decision support using spatially aware agent-based models and simulations, and the analysis and visualization of datasets produced by complex, often social, systems. He has authored several journal articles, peer reviewed conference papers, and book chapters on applied agent-based modeling from tax evasion to combat, and fraud detection to legal institution design. Matt received his AB in Anthropology from Kenyon College, his MPA from Indiana University’s School of Public and Environmental Affairs, his JD from George Washington University’s Law School, and his PhD in Computational Social Science from George Mason University’s Krasnow Institute for Advanced Study, Dept. of Computational Social Science. Matt has taught applied agent-based modeling and data mining at George Mason University, the United States Military Academy, the Università del Salento, and at MITRE’s internal education facility and various government agencies. Matt has also been an active member of the board of the Computational Social Science Society of the Americas for more than a dozen years.

Andrew J. Collins, Ph.D., is an associate professor at Old Dominion University in the Department of Engineering Management and Systems Engineering. He has a Ph.D. in Operations Research from the University of Southampton, and his undergraduate degree in Mathematics was from the University of Oxford. He has published over 100 peer-reviewed articles. He has been the Principal Investigator on projects funded to the amount of approximately $5 million. Dr. Collins' interests are the advancement of agent-based modeling (ABM) and the integration of game theory concepts in ABM. has developed several research simulations, including an award-winning investigation into the foreclosure contagion that incorporated social networks. His website and full resume are at www.drandrewjcollins.com.

[CSSSA Webinar] Validation of Agent-based Models – Drs. Matthew Koehler & Andrew Collins

Dr. Arianna Salazar-Miranda presents "the 15-minute city quantified using human mobility data."

Amid rising congestion and transport emissions, policymakers are embracing the ‘15-minute city’ model, which envisions neighborhoods where basic needs can be met within a short walk from home. Prior research has primarily examined amenity access without exploring its relationship to behavior. We introduce a measure of local trip behavior using GPS data from 40 million US mobile devices, defining ‘15-minute usage’ as the proportion of consumption-related trips made within a 15-minute walk from home. Our findings show that the median resident makes only 14% of daily consumption trips locally. Differences in access to local amenities can explain 84% and 74% of the variation in 15-minute usage across and within urban areas, respectively. Historical data from New York zoning policies suggest a causal relationship between local access and 15-minute usage. However, we find a trade-off: increased local usage correlates with higher experienced segregation for low-income residents, signaling potential socio-economic challenges in achieving local living.

[CSSSA Webinar] The 15-minute City Quantified – Dr. Arianna Salazar-Miranda

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The Computational Social Science Society of the Americas (CSSSA) is a professional society that aims to advance the field of computational social science in all its areas, including basic and applied orientations, by holding conferences and workshops, promoting standards of scientific excellence in research, teaching, and publishing research findings and results.

CSSSA has the goals of:

1) Improve the scientific credibility of computational social science.

2) Maintain an institutionally neutral society characterized by scientific integrity.

3) Promote the advancement of computational social science through scientific exchange, transparency, and open discussion.

Scientific progress requires scientists to build upon previous research and developments of their peers and give explicit credit to these peers — to foster trust and integrity. Publishing your research, providing transparency into your algorithms and computer models is strongly encouraged via the Open Agent-Based Modeling Consortium. In addition to providing an open repository for models and simulations OpenABM also provides a valuable forum for collaboration, learning, and networking.

Email the CSSSA officers at: info@computationalsocialscience.org