4. å
Psychohistory
“PSYCHOHISTORY - … Gaal
Dornick, using non-mathematical
concepts, has defined
psychohistory to be that branch
of mathematics which deals with
the reactions of human
conglomerates to fixed and social
stimuli…”
Isaac Asimov, Foundation
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5
Physical - social dichotomy
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6
The physical modelling of
social systems
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7. æ
The science of
complexity
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8
Some concepts
Network: System of interconnected things.
Nodes: individual elements in network
Links: relationships between nodes
Hubs: super nodes.
Graphs: graphical representation of networks
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Characteristics
Long tails. Cascading failures: Potential
vulnerability if super hubs
Connectedness: “Six
are removed.
degrees of separation”
Tipping points, cascading
Accumulation of links: “the
effects, mob behaviour .
rich get richer”
Centrality: some hubs can
Hyper-accumulation of links:
be more important if they
“the winner takes all”
have a central role in the
Pareto distribution: 80-20 network.
rule Robustness: resilient to
random attacks
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16
Six degrees of interdisciplinary
collaborations
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17
Six degrees of scholarly
citation
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18
Scale-free sexual contacts
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19
Power law of Mandarin
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20
Long tail in WoW guild sizes
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21
Scale-free genetic clusters
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22
Scale-free yeast proteins
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Internet from network
theory standpoint
Distributed architecture
Tending towards national and regional centralisation of nodes.
Scale-free.
Displays some small world clusters.
Power laws at high level of granularity.
P2P networks, botnets, all highly resilient.
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29
How can complex studies
help?
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