Subspace clustering

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Subspace clustering Feng Zhou BCMI 2007.5.30

Outline • Introduction • Bottom Up Search Methods – CLIQUE – DOC

• Top‐down Search Methods – ORCLUS – PROCLUS

Introduction  (SIGKDD 2004, ASU) • Flaws of Traditional Methods – Curse of Dimensions

– Relevance of clusters and dimensions

Introduction II • Goals – Number of clusters (Usually specified by user) – The cluster each item belongs  – The dimensions each cluster exists in

• Hierarchy of existing methods

CLIQUE (SIGMOD 1998, IBM Almaden Research Center)

• Features – Axis‐parallel dimension – Density‐based

• Denotations – Unit – Region

CLIQUE II Algorithm • Identification of subspaces that contain clusters. – Using an Apriori‐style algorithm to find dense units.  • Candidates of  k dimensional dense units