Class09

Class09 - What is Cluster Analysis? Finding groups of...

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Unformatted text preview: What is Cluster Analysis? Finding groups of objects such that the objects in a group will be similar (or related) to one another and different from (or unrelated to) the objects in other groups Inter-cluster distances are maximized Intra-cluster distances are minimized Applications of Cluster Analysis Understanding Group related documents for browsing, group genes and proteins that have similar functionality, or group stocks with similar price fluctuations Summarization Reduce the size of large data sets Discovered Clusters Industry Group 1 Applied-Matl-DOWN,Bay-Network-Down,3-COM-DOWN, Cabletron-Sys-DOWN,CISCO-DOWN,HP-DOWN, DSC-Comm-DOWN,INTEL-DOWN,LSI-Logic-DOWN, Micron-Tech-DOWN,Texas-Inst-Down,Tellabs-Inc-Down, Natl-Semiconduct-DOWN,Oracl-DOWN,SGI-DOWN, Sun-DOWN Technology1-DOWN 2 Apple-Comp-DOWN,Autodesk-DOWN,DEC-DOWN, ADV-Micro-Device-DOWN,Andrew-Corp-DOWN, Computer-Assoc-DOWN,Circuit-City-DOWN, Compaq-DOWN, EMC-Corp-DOWN, Gen-Inst-DOWN, Motorola-DOWN,Microsoft-DOWN,Scientific-Atl-DOWN Technology2-DOWN 3 Fannie-Mae-DOWN,Fed-Home-Loan-DOWN, MBNA-Corp-DOWN,Morgan-Stanley-DOWN Financial-DOWN 4 Baker-Hughes-UP,Dresser-Inds-UP,Halliburton-HLD-UP, Louisiana-Land-UP,Phillips-Petro-UP,Unocal-UP, Schlumberger-UP Oil-UP Clustering precipitation in Australia What is not Cluster Analysis? Supervised classification Have class label information Simple segmentation Dividing students into different registration groups alphabetically, by last name Results of a query Groupings are a result of an external specification Graph partitioning Some mutual relevance and synergy, but areas are not identical Notion of a Cluster can be Ambiguous How many clusters? Four Clusters Two Clusters Six Clusters Types of Clusterings A clustering is a set of clusters Important distinction between hierarchical and partitional sets of clusters Partitional Clustering A division data objects into non-overlapping subsets (clusters) such that each data object is in exactly one subset Hierarchical clustering A set of nested clusters organized as a hierarchical tree Partitional Clustering Original Points A Partitional Clustering Hierarchical Clustering p4 p1 p3 p2 p4 p1 p3 p2 p4 p1 p2 p3 p4 p1 p2 p3 Traditional Hierarchical Clustering Non-traditional Hierarchical Clustering Non-traditional Dendrogram Traditional Dendrogram Other Distinctions Between Sets of Clusters Exclusive versus non-exclusive In non-exclusive clusterings, points may belong to multiple clusters. Can represent multiple classes or border points Fuzzy versus non-fuzzy In fuzzy clustering, a point belongs to every cluster with some weight between 0 and 1 Weights must sum to 1 Probabilistic clustering has similar characteristics Partial versus complete In some cases, we only want to cluster some of the data Heterogeneous versus homogeneous Cluster of widely different sizes, shapes, and densities Types of Clusters...
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Class09 - What is Cluster Analysis? Finding groups of...

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