360 likes | 452 Views
Emergent Structure Models: Applications to World Politics. Prof. Lars-Erik Cederman Center for Comparative and International Studies (CIS) Seilergraben 49, Room G.2, lcederman@ethz.ch Christa Deiwiks, CIS Room E.3, deiwiks @icr.gess.ethz.ch http://www.icr.ethz.ch/teaching/compmodels
E N D
Emergent Structure Models: Applications to World Politics Prof. Lars-Erik Cederman Center for Comparative and International Studies (CIS) Seilergraben 49, Room G.2,lcederman@ethz.ch Christa Deiwiks, CIS Room E.3, deiwiks@icr.gess.ethz.ch http://www.icr.ethz.ch/teaching/compmodels Week 12
Cumulative war-size plot, 1820-1997 Data Source: Correlates of War Project (COW)
Self-organized criticality Power-law distributed avalanches in a rice pile Per Bak’s sand pile
Theory: Self-organized criticality log f • Slowly driven systems that fluctuate around state of marginal stability while generating non-linear output according to a power law. • Examples: sandpiles, semi-conductors, earthquakes, extinction of species, forest fires, epidemics, traffic jams, city populations, stock market fluctuations, firm size f Input Output s-a log s s Complex System
War clusters in Geosim t = 3,326 t = 10,000
log P(S > s) (cumulative frequency) log s (severity) Simulated cumulative war-size plot log P(S > s) = 1.68 – 0.64 log s N = 218 R2 = 0.991 See “Modeling the Size of Wars” American Political Science Review Feb. 2003
2. Modeling state sizes: Empirical data log Pr (S > s) (cumulative frequency) log S ~ N(5.31, 0.79) MAE = 0.028 log s (state size) 1998 Data: Lake et al.
log Pr (S > s) (cumulative frequency) log s (state size) Simulated state-size distribution log S ~ N(1.47, 0.53) MAE = 0.050
Simulating global democratization Source: Cederman & Gleditsch 2004
A simulated democratic outcome t = 0 t = 10,000
OrgForms: A dynamic network model Conquest Technological Progress Systems Change Organizational Bypass
OrgForms Exploring geopolitics using agent-based modeling GeoSim 0 GeoSim 5 GeoSim 4 GeoContest
Toward more realistic models of civil wars • Our strategy: • Step I: extending Geosim framework • Step II: conducting empirical research • Step III: back to computational modeling
Step I: Modeling nationalist insurgencies • Target Fearon & Laitin. 2003. Ethnicity, Insurgency, and Civil War. American Political Science Review 97: 75-90 • Weak states that cannot control their territory are more prone to insurgency • Use agent-based modeling to articulate identity-based mechanisms of insurgency • Will appear in Cederman (forthcoming). Articulating the Geo-Cultural Logic of Nationalist Insurgency. In Order, Conflict, and Violence, eds. Kalyvas & Shapiro. Cambridge University Press.
3##44#2# 32144421 Step I: Main building blocks • National identities • Cultural map • State system • Territorial obstacles
Step I: Conclusions • Important hunches: • Going beyond macro correlations • Developing mechanisms based on explicit actor constellations • Focus on center-periphery power balance • Location of ethnic groups crucial • But the model is too complex and artificial
Step II: Empirical research • Beyond fractionalization (Cederman & Girardin, forthcoming in the APSR) • Expert Survey of Ethnic Groups (Cederman, Girardin & Wimmer, in progress) • Geo-Referencing of Ethnic Groups (Cederman, Rød & Weidmann, just completed) • Modeling Ethnic Conflict in Center-Periphery Dyads (Buhaug, Cederman & Rød)
Step II: Constructing the N* index State-centric ethnic configuration E*: Micro-level mechanism M*: p(1) s1 EGIP p(2) p(i) s0 s2 … p(n-1) sn-1 r(i)=
Step II: Expert Survey of Ethnic Groups • Project together with • Luc Girardin (ETH) • Andreas Wimmer (UCLA) • Web-based interface in order to expand coding of ethnic groups and their power access to the rest of the world with the help of area experts
Step II: Geo-Referencing of Ethnic Groups • Scanning and geo-coding ethnic groups • Polygon representation • Based on Atlas Narodov Mira (1964)
Step III: GROWLab • Technical approach • Follow same tradition as other toolkits, but higher level of abstraction • Tailored to geopolitical modeling, but might be useful to others • Java based; targeted at programming literates • Main features • Support for agent hierarchies • Support for complex spatial relationships (e.g. borders) • Support for GIS data (raster with geodetic distance computation) • Discrete spaces • Integrated GUI • Comes with 13 example models • Batch runs (cluster support in development) • Available at: http://www.icr.ethz.ch/research/growlab/