Regensburg 2004 – scientific programme

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AKSOE: Physik sozio-ökonomischer Systeme

AKSOE 5: Soziale Systeme und Entscheidungsmodelle II

AKSOE 5.2: Talk

Tuesday, March 9, 2004, 14:30–15:00, H8

Epidemics in hierarchical social networks — •Marian Brandau and Steffen Trimper — Fachbereich Physik, Friedmann-Bach-Platz, 06108 Halle

Epidemiological processes in hierarchical social networks are studied within a so called susceptible–infected–refractory model (SIR). Within the network model, a population of individuals may be characterized by certain independent hierarchies H (or dimension) to which they belong it (family, the acquaintance, job etc.). The degree of homophily (relationship) in the hierarchy is determined by a parameter α. Detailed numerical simulations reveal that for H > 1, global spreading results regardless of the degree of homophily α. For H = 1, a transition from global to local spread occurs as the population becomes decomposed into increasingly homophilous groups. Multiple dimensions in classifying individuals (nodes) thus make a society (computer network) highly susceptible to large scale outbreaks of infectious diseases (viruses). The SIR–model is extended to an SIRS–model, where already infected persons may enter the dynamical process after a finite waiting time.