Emergence of Scaling in Random Networks -...

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Emergence of Scaling in Random Networks

Albert-László Barabási & Réka AlbertScience, 286 (1999)

Scale-free Networks

Log k

Log

P(k

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Log

P(k

)

Log k

Log

P(k

)en.wikipedia.org

Log k

Log

P(k

)en.wikipedia.org nealcaren.web.unc.edu

Log k

Log k

Log

P(k

)en.wikipedia.org

biomedicalcomputationreview.org

nealcaren.web.unc.edu

Log k

World wide web Protein

Interation

k

biomedicalcomputationreview.org(Barabasi, 1999)

The Model

„rich-get-richer“„preferrential attachment“

+

+

+

+

+

1. „preferential attachment“

→power law:

2. „growth“:

→ stationary:

The Model

scale invariance!

NetLogo Model

1. „preferential attachment“

→power law:

2. „growth“:

→ stationary:

Model Analysis

scale invariance!

The exponent

(Barabasi, 1999)

Typical values for

problem Barabasi, 1999 Price, 1976

WWW 2.1

Citation network 3.0 2.5-3.0

Actor collaboration 2.3

Power grid 4.1

Erdös Renyi Model (1960)

N = const.