Two Medoid-Based Algorithms for Clustering Sets

This paper proposes two algorithms for clustering data, which are variable-sized sets of elementary items. An example of such data occurs in the analysis of a medical diagnosis, where the goal is to detect human subjects who share common diseases to possibly predict future illnesses from previous me...

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Main Authors: Libero Nigro, Pasi Fränti
Format: Article
Language:English
Published: MDPI AG 2023-07-01
Series:Algorithms
Subjects:
Online Access:https://www.mdpi.com/1999-4893/16/7/349
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author Libero Nigro
Pasi Fränti
author_facet Libero Nigro
Pasi Fränti
author_sort Libero Nigro
collection DOAJ
description This paper proposes two algorithms for clustering data, which are variable-sized sets of elementary items. An example of such data occurs in the analysis of a medical diagnosis, where the goal is to detect human subjects who share common diseases to possibly predict future illnesses from previous medical history. The first proposed algorithm is based on K-medoids and the second algorithm extends the random swap algorithm, which has proven to be capable of efficient and careful clustering; both algorithms depend on a distance function among data objects (sets), which can use application-sensitive weights or priorities. The proposed distance function makes it possible to exploit several seeding methods that can improve clustering accuracy. A key factor in the two algorithms is their parallel implementation in Java, based on functional programming using streams and lambda expressions. The use of parallelism smooths out the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>O</mi><mo stretchy="false">(</mo><msup><mi>N</mi><mn>2</mn></msup><mo stretchy="false">)</mo></mrow></semantics></math></inline-formula> computational cost behind K-medoids and clustering indexes such as the Silhouette index and allows for the handling of non-trivial datasets. This paper applies the algorithms to several benchmark case studies of sets and demonstrates how accurate and time-efficient clustering solutions can be achieved.
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spelling doaj.art-d66fce0d1ccb4d26a4293168067aaafb2023-11-18T17:59:24ZengMDPI AGAlgorithms1999-48932023-07-0116734910.3390/a16070349Two Medoid-Based Algorithms for Clustering SetsLibero Nigro0Pasi Fränti1Engineering Department of Informatics Modelling Electronics and Systems Science, University of Calabria, 87036 Rende, ItalySchool of Computing, Machine Learning Group, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, FinlandThis paper proposes two algorithms for clustering data, which are variable-sized sets of elementary items. An example of such data occurs in the analysis of a medical diagnosis, where the goal is to detect human subjects who share common diseases to possibly predict future illnesses from previous medical history. The first proposed algorithm is based on K-medoids and the second algorithm extends the random swap algorithm, which has proven to be capable of efficient and careful clustering; both algorithms depend on a distance function among data objects (sets), which can use application-sensitive weights or priorities. The proposed distance function makes it possible to exploit several seeding methods that can improve clustering accuracy. A key factor in the two algorithms is their parallel implementation in Java, based on functional programming using streams and lambda expressions. The use of parallelism smooths out the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>O</mi><mo stretchy="false">(</mo><msup><mi>N</mi><mn>2</mn></msup><mo stretchy="false">)</mo></mrow></semantics></math></inline-formula> computational cost behind K-medoids and clustering indexes such as the Silhouette index and allows for the handling of non-trivial datasets. This paper applies the algorithms to several benchmark case studies of sets and demonstrates how accurate and time-efficient clustering solutions can be achieved.https://www.mdpi.com/1999-4893/16/7/349unsupervised clusteringK-meansK-medoidsrandom swapseeding methodsclustering sets
spellingShingle Libero Nigro
Pasi Fränti
Two Medoid-Based Algorithms for Clustering Sets
Algorithms
unsupervised clustering
K-means
K-medoids
random swap
seeding methods
clustering sets
title Two Medoid-Based Algorithms for Clustering Sets
title_full Two Medoid-Based Algorithms for Clustering Sets
title_fullStr Two Medoid-Based Algorithms for Clustering Sets
title_full_unstemmed Two Medoid-Based Algorithms for Clustering Sets
title_short Two Medoid-Based Algorithms for Clustering Sets
title_sort two medoid based algorithms for clustering sets
topic unsupervised clustering
K-means
K-medoids
random swap
seeding methods
clustering sets
url https://www.mdpi.com/1999-4893/16/7/349
work_keys_str_mv AT liberonigro twomedoidbasedalgorithmsforclusteringsets
AT pasifranti twomedoidbasedalgorithmsforclusteringsets