Small World Clustering Algorithms

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Small World Clustering Algorithms

• Brant Chee

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Experiments

• 3 clustering algorithms
• Complete Link (Cluto)
• K means (Cluto)
• Small World

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Test Collections
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Experimental Setup

• Parameters left at package defaults
• Clustered with n 50,100,150 and 200.
• Clusters with less than 4 elements or more than
  50 elements were eliminated and the clustering
  which resulted in less than 40 clusters was
  chosen to be evaluated.

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Quantitative Results
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Quantitative Results II
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Qualitative Evaluation

• 2 Criteria Utility and Coherence
• 3 point scale 1 good, 2 poor, 3 bad
• Good gt60 of articles
• Poor 59-41
• Bad lt40
• Evaluate terms in cluster to get context.

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Quantitative Results Cont
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Sample Session
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Other Approaches

• Statistical Methods

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Other Clustering Approaches

• Can we choose other types of clustering
  algorithms which could provide better quality
  results or provide better cluster labels?
• SOM (Self Organizing Map)
• Slow for high numbers of dimensions and large
  numbers of objects.
• Carrot2
• Slow for large numbers of items.
• Huge memory consumption.

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Random Projection

• Can we reduce the dimensionality of vectors (ie
  50,000?1000) while preserving distances?
• Speed up similarity calculations
• Various methods
• Random projection.
• Latent semantic indexing.
• Multi Dimensional Scaling

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Very Sparse Random Projections

• A ? R be our n points in D dimensions
• A x Random matrix ? RDk
• R of entries in -1, 0, 1 with probabilty
• O(nDk n2k)

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Reducing Dimensionality

• Bank Dataset 11,000 articles from 11 categories
  in Dmoz.
• 11,000 articles reduced from 30K terms 1GB heap
  in 11s.
• Increase in Purity and decrease in Entropy
  (measures of clustering quality).

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MI on Phrases

• More context than single words
• More meaningful term clusters

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Other approaches

• Knowledge Intensive Approaches

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Hypernym

• Is-a relationship
• Shakespeare is an author.
• Pug is a dog.
• Implicitly hierarchical.
• Basis of many ontology and semantic networks.
• Wordnet
• UMLS

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Portion of the UMLS Semantic Network Biologic
Function
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Hypernym Relations

• NP such as , NP (or and) NP
• Vegetables such as Beets, Carrots and Peas.
• Such NP as NP, (orand) NP
• works by such authors as Herrick, Goldsmith and
  Shakespeare.
• NP , NP , orand other NP
• Bruises, , broken bones or other injuries
• NP , including NP, orand NP
• All common-law countries, including Canada and
  England
• NP , especially NP, orand NP
• most European countries, especially France,
  England and Spain.

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Uses of Hypernym Trees

• Search
• Query Expansion
• Facted metadata
• Clustering
• Parent node defines a cluster
• Keyword assignment

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Trivial Hypernyms

• organic compounds d-ribose
• organic compounds d-arabinose
• organic compounds l-arabinose
• organic compounds sucrose
• substances cortisone
• substances vitamins a and c
• substances zinc
• organs liver
• organs kidney
• sugar-containing products honey
• sugar-containing products jam
• sugar-containing products glucose
• sugar-containing products fruit juice
  concentrates
• sugar-containing products tomato
• largely populated countries china
• largely populated countries russia

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Bad Hypernyms

• suicidal patients appears
• other agents plasmin
• other agents plasminogen
• such common sensations illness
• phenomena founder effects
• phenomena migration
• phenomena gene flow
• clinical manifestations 80
• chemical agents homocystine
• no other explanation anencephaly
• conditions azure a-0.5 nahco3 solution
• conditions ph 8.1
• fewer side-effects vegetative disfunction
• techniques carpentier
• techniques 's ring

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Good? Hypernyms

• entirely synthetic steroids norgestrel and
  quingestanol
• menstrual disorders metrorrhagia
• menstrual disorders oligoamenorrhea
• menstrual disorders amenorrhea
• mild venous disorders swollen veins
• mild venous disorders heavy limbs
• mild venous disorders varicosities
• obstructive pulmonary lung diseases alveolar
  proteinosis
• obstructive pulmonary lung diseases pneumonia
• obstructive pulmonary lung diseases asthma
• obstructive pulmonary lung diseases
  bronchiectasis
• obstructive pulmonary lung diseases cystic
  fibrosis
• choline analogues n,n'-dimethylethanolamine
• choline analogues n-monomethylethanolamine
• choline analogues ethanolamine
• 3alpha-oh-containing steroids androsterone