Agent-Based Models in Social Sciences: Examples and Applications
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Presentation Transcript
Today’s agenda • Sample runs of simple models • More complex models • Where to find more models • Gearing up
Simple sample models • Schelling’s segregation model RePast • Traffic simulation NetLogo • AIDS NetLogo • Sugerscape Ascape • Labour Market Simulation RePast
Example 1: Neighborhood segregation Micro-level rules of the game Stay if at least a third of neighbors are “kin” < 1/3 Thomas C. Schelling Micromotives and Macrobehavior Move to random location otherwise
Example 2: Traffic simulation (NetLogo) • Model of the movement of cars on a highway • Each car follows a simple set of rules: • if there’s car close ahead, it slows down • if there’s no car ahead, it speeds up • The project demonstrates how traffic jams form spontaneously without obstacles
Example 3: AIDS (NetLogo) • Simulate the spread of the human immunodeficiency virus (HIV), via sexual transmission • Control of the • population's tendency to practice abstinence • amount of time an average "couple" in the population will stay together • population's tendency to use condoms • population's tendency to get tested for HIV
Example 4: Sugarscape (Ascape) • Series of models introduced by Epstein and Axtell 1996 Growing Artificial Societies MIT Press • Emergent features: • wealth distributions • social networks • migration • population dynamics • conflict patterns • price formation • credit networks • Programmed in Ascape
Example 5: Labour Market • Agents represent workers in an international labour market • Agents’ main goal is to have a job and friends • Jobs are available according to a country’s economic situation • If the agent has been unhappy for a certain time period, it moves to another country (Model developed by Pedro Thomi as SS04 CompModels term project)
Complex sample models • Anasazi village formation • Nationalist insurgencies in Geosim • UrbanSim • ILUTE
Example 1: Anasazi Village Formation • Gumerman et al. 2002 SFI Working Paper 02-16-067 (among others) • Reconstruction of settlement patterns and demographics of pueblo Indians in the American Southwest • The main puzzle pertains to the group’s sudden disappearance • Based on the Sugarscape model, and thus also programmed in Ascape
3##44#2# 32144421 Example 2: Geosim • Geopolitical simulation system • Cederman 2004 “Articulating the Mechanisms of Nationalist Insurgencies” • Based on RePast • National identities • Cultural map • State system • Territorial obstacles
Example 3: UrbanSim • UrbanSim is a simulation model for integrated planning and analysis • Developed at the Univ. of Washington, Seattle • Features decision-making by households, businesses, developers and governments • http://www.urbansim.org/
Example 4: ILUTE • Integrated Land Use Transportation Modeling from Toronto http://www.civ.utoronto.ca/sect/traeng/ilute/
Where to find more models: Links • See “Resources” under class home page • Santa Fe Institute: http://www.santafe.edu/ • Center for the Study of Complex Systems at the University of Michigan: http://www.pscs.umich.edu/ • European web sites on Computer simulation of societies http://www.soc.surrey.ac.uk/research/simsoc/and “European Social Simulation Association” http://essa.eu.org/ • For the US counterpart, see http://www.dis.anl.gov/naacsos • Leigh Tesfatsions’s site on computational economics:http://www.econ.iastate.edu/tesfatsi/ace.htm • See also the Journal of Artificial Societies and Social Simulation: http://jasss.soc.surrey.ac.uk/JASSS.html
Gearing up • Installing the Java 2 SDK • Installing IntelliJ IDEA • Create the main project definition • Create and run a simple test program • Adding the RePast module (and optionally Ascape and NetLogo) • Setting up Schelling’s segregation model (depends on RePast)
Development Environment Integrated Development Environment e.g. IDEA Java compiler Editor int a = 12; if (a == b) b++; else a++; JVM Java source code Java libs Repast libs