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Fast global k-means clustering using cluster membership and inequality. Presenter : Lin, Shu -Han Authors : Jim Z.C. Lai, Tsung -Jen Huang. Pattern Recognition (PR, 2010). Outline. Motivation Objective Methodology Experiments Conclusion Comments. Motivation. FGKM and MGKM
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Fast global k-means clustering using cluster membership and inequality Presenter : Lin, Shu-Han • Authors : Jim Z.C. Lai, Tsung-Jen Huang Pattern Recognition(PR, 2010)
Outline • Motivation • Objective • Methodology • Experiments • Conclusion • Comments
Motivation • FGKM and • MGKM Have the same computational complexity MGKM Claims that it is moreeffectivethanFGKM (see 2008.PR.8.書漢.1027.Modified global k-means algorithm for minimum sum-of-squares clustering problems)
Objectives , th=.9999 • Develop a set of inequalities to • Speed up FGKM and MGKM, called MFGKM • Using Karhunen-Loeve Transform (KLT) • closely related to the Principal Component Analysis (PCA)
Methodology–MFGKM Red = proposed (or s Yj’ , called MCS)
Methodology– Candidate set construction algorithm (Cont.) 1. r10=2,r10=d(x10,c) |8.2-7.2|=1 1+|2.2-4.2|=3>r10,deletex10, x10cannotbethenearestneighborofx8 l+p m 1 2
Methodology– Candidate set construction algorithm (Cont.) 2. rmax=2 m
Methodology– Candidate set construction algorithm (Cont.) 3.
Methodology– Candidate set construction algorithm (Cont.) 4. Diff(distortion) Diff=(r9-d(x8,x9))+(r10-d(x8,x10)) =2-1+2-1 m Return2andcenterofx9andx7
Experiments–Distortion Leastdistortion Faster,butdistortion 17
Conclusions • GKM • FGKM:faster,butlocal • MGKM:betterperformancethenFGKM,butneedsmorecomputationalcomplexity • MFGKM:faster,andbetterthenMGKM • MFGKM+MCS:fastestmethod,andperformanceiscomparabletoMGKM
Comments • Advantage • Improvebothperformanceandspeed • Drawback • … • Application • …
Methodology– k-Means sensitive to the choice of a starting point 20
Methodology– The GKM algorithm Objectivefunction 21
Methodology– Objectivefunction • Oldversion • Reformulatedversion 22
Methodology– fast GKM algorithm • Oldversion • Proposedversion(auxiliaryclusterfunction) k-1 k-1 j y i i 23
Methodology– modifiedGKM algorithm • Proposedversion S2 k-1 S2 S2 ci i S2 S2 24