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genetics
semantics
economics
simulation
organization
neural
evolution
dynamics
algorithms
mathematics
artificial
physics
chaos
alife
science
systems
complexity
ecology
complex
nonlinear
networks
ai
markets
emergence
behavior
theory
complexsystems
research
evolutionary
biology
information
computation
math
computational
community
art
visualization
computing
life
environment
cognition
society
optimization
ecosystem
robustness
Fig. 5.11
Folksonomy
graph,
considering
only
correlations
corresponding
to
central
tag
'complexity'
5.4.2
Constructing the Tag Correlation (Folksonomy) Graphs
In order to exemplify our approach, we collected the data and constructed vi-
sualizations for a restricted class of 50 tags, all related to the tag 'complexity.'
Our goal in this example was to examine which sciences the user community of
del.icio.us expresses as most related to the problematic term 'complexity science.'
The visualizations were made on Pajek (Batagelj and Mrvar 1998). The purpose
of the visualization was to study whether the proposed method retrieves connection
between a central tag 'complexity' and related disciplines. We considered two cases:
￿
Only the dependencies between the tag “complexity” and all other tags in the
subset are taken into account when building the graph (Fig. 5.11 ).
￿
The weights of all the 1,175 possible edges between the 50 tags are considered
(Fig. 5.12 ).
In both figures, the size of the nodes is proportional to the absolute frequencies of
each tag, while the distances are, roughly speaking, inversely related to the distance
measure as returned by the spring-embedder algorithm. 7 We tested two energy
measures for the 'springs' attached to the edges in the visualization: Kamada-Kawai
and Fruchterman-Reingold (Batagelj and Mrvar 1998). For lack of space, only the
visualization returned by Kamada-Kawai is presented here, since we found it more
faithful to the proportions in the data.
7 For two of the tags, namely 'algorithms' and 'networks,' morphological stemming was employed.
So both absolute frequencies and co-dependencies were summed over the singular form tag, i.e.
'network' and the plural 'networks,' since both forms occur with relatively high frequency.
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