Measuring the Semantic Web

1
Measuring the Semantic Web

• Rosa Gil Iranzo
• GRIHO, Universitat de Lleida, Spain
• Roberto García González
• rhizomik.net

2
Outline

• Motivation why to measure?
• Approach complex systems
• Measuring applying statistical tools
• Results is the semantic web a complex system?
• Conclusions

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Motivation

• Semantic Web, an open evolving system.
• TimBL Looking for a metric in The Fractal
  nature of the Web, Design Issues.
• How is it measured? Whats the metric?

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Motivation

• Why to measure?
• From the TimBLWeaving the Web Semantic Web
  plan
• Where we are now?
• How is it evolving?
• Are we going where it was planned?

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Approach

• Semantic Web as complex as many other systems
• metabolic networks
• acquaintance networks
• food webs
• neural networks
• The WWW

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Approach

• This complex systems are studied using Complex
  Systems (CS) Analysis.
• Statistical tools for graph models
• Degree Distribution
• Small World
• Clustering Coefficient

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Approach

• Model the system as a graph.
• CS graph characteristics
• Degree Distributionpower law, P(k) k - r
• Small Worldsmall diameter, d drandom
• Clustering Coefficienthigh clustering, C gtgt
  Crandom

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Measuring

• Is the Semantic Web a CS?
• It is already a graph.
• Crawl all DAML Ontologies Library
• 2003 56,592 nodes, 131,130 arcs
• 2005 307,231 nodes and 588,890 arcs
• Statistical study of the graph.

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Results
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Results

• It is a small worlddiameter smaller than random
  graph, d4.37 while drand7.23
• It has high clusteringC0.152 while
  Crandom0.0000895
• It is scale freepower law degree distribution,
  P(k)k 1.19

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Results
CDF (Cumulative Distribution Function)
Degree
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Conclusions

• The Semantic Web is a Complex System.
• Behaves like a living system (neural network,
  food web, proteins net,), i.e. the same
  dynamics.
• Same behaviour 2003-2005.

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Conclusions

• Just exploring applications
• Degree dynamics for trust computation.
• Ontology alignment (clusters, centrality,).
• Metadata high volumes management.
• etc.
• More information and tools at http//rhizomik.net
  /livingsw

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Thank you for your attention

• Roberto García ltroberto_at_rhizomik.netgtRosa Gil
  ltrgil_at_diei.udl.esgt