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TESI DOCTORAL - La Salle

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D.2. Experiments on selection-based self-refining<br />

φ (NMI)<br />

1<br />

0.5<br />

0<br />

E<br />

λref<br />

λ c 2<br />

λ c 5<br />

λ c 10<br />

φ (NMI)<br />

HGPA<br />

1<br />

0.5<br />

0<br />

(c) HGPA<br />

φ (NMI)<br />

1<br />

0.5<br />

0<br />

E<br />

E<br />

λref<br />

λ c 2<br />

λ c 5<br />

λ c 10<br />

λ c 15<br />

λ c 15<br />

λ c 20<br />

λ c 30<br />

λ c 40<br />

λ c 50<br />

λ c 60<br />

λ c 75<br />

λ c 90<br />

CSPA<br />

(a) CSPA<br />

λref<br />

λ c 2<br />

λ c 5<br />

λ c 10<br />

φ (NMI)<br />

KMSAD<br />

1<br />

0.5<br />

0<br />

E<br />

(f) KMSAD<br />

λ c 20<br />

λ c 30<br />

λ c 40<br />

λ c 50<br />

λ c 60<br />

λ c 75<br />

λ c 90<br />

λref<br />

λ c 2<br />

λ c 5<br />

λ c 10<br />

λ c 15<br />

λ c 20<br />

λ c 30<br />

λ c 40<br />

λ c 50<br />

λ c 60<br />

λ c 75<br />

λ c 90<br />

φ (NMI)<br />

MCLA<br />

1<br />

0.5<br />

0<br />

(d) MCLA<br />

φ (NMI)<br />

1<br />

0.5<br />

0<br />

E<br />

E<br />

λref<br />

λ c 2<br />

λ c 5<br />

λ c 10<br />

λ c 15<br />

λ c 15<br />

λ c 20<br />

λ c 30<br />

λ c 40<br />

λ c 50<br />

λ c 60<br />

λ c 75<br />

λ c 90<br />

λref<br />

λ c 2<br />

λ c 5<br />

λ c 10<br />

EAC<br />

(b) EAC<br />

φ (NMI)<br />

SLSAD<br />

1<br />

0.5<br />

0<br />

E<br />

(g) SLSAD<br />

λ c 20<br />

λ c 30<br />

λ c 40<br />

λ c 50<br />

λ c 60<br />

λ c 75<br />

λ c 90<br />

λref<br />

λ c 2<br />

λ c 5<br />

λ c 10<br />

λ c 15<br />

λ c 20<br />

λ c 30<br />

λ c 40<br />

λ c 50<br />

λ c 60<br />

λ c 75<br />

λ c 90<br />

ALSAD<br />

(e) ALSAD<br />

λ c 15<br />

λ c 20<br />

λ c 30<br />

λ c 40<br />

λ c 50<br />

λ c 60<br />

λ c 75<br />

λ c 90<br />

Figure D.15: φ (NMI) boxplots of the cluster ensemble E, the selected cluster ensemble component<br />

λref and the self-refined consensus clustering solutions λc p i on the Ionosphere data<br />

collection across all the consensus functions employed. The green dashed vertical line identifies<br />

the clustering solution selected by the supraconsensus function in each experiment.<br />

quality of that of the selected cluster ensemble component λref are obtained for most consensus<br />

functions —in fact, the clearest exceptions to this behaviour are EAC and HGPA.<br />

However, the supraconsensus function is not capable of selecting those better quality clusterings<br />

as the final partition in most cases, which again gives an idea of its limited performance.<br />

D.2.7 MFeat data set<br />

Figure D.18 presents the φ (NMI) boxplots of the clusterings obtained after applying the<br />

selection-based self-refining process on the MFeat data set. Notice how, for four out of<br />

the seven consensus functions (CSPA, MCLA, ALSAD and KMSAD), notable quality gains<br />

are obtained (i.e. at least one of the refined clusterings attains a higher φ (NMI) than the<br />

selected cluster ensemble component λref). Unfortunately, the supraconsensus function fails<br />

to select these high quality partitions as the final clustering solution λ c final, as it constantly<br />

selects λref as the optimal one, which is the correct option when self-refining is based on<br />

the EAC, HGPA and SLSAD consensus functions.<br />

352

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