A coarse-to-fine two-step method for semisupervised classification using quasi-linear Laplacian SVM

Bo Zhou, Weite Li, Takayuki Furuzuki

Research output: Contribution to journalArticle

Abstract

This paper proposes a two-step method to construct a nonlinear classifier based on semisupervised learning in a coarse-to-fine way. In the first step, a recursive density-based spatial clustering of applications with noise clustering algorithm is first introduced to find a group of density clusters, each of which contains only one kind of class labels. An SK algorithm is then applied to pairs of density clusters containing different class labels to find a set of local linear classifiers, which forms a coarse nonlinear separating boundary crossing the low-density areas by interpolating the local linear classifiers. In the second step, a Laplacian support vector machine (LapSVM) formulation based on graph construction is applied to further implicitly optimize the parameter set of the nonlinear coarse classifier. As a result, the fine-tuned nonlinear classifier is constructed in exactly the same way as a standard LapSVM, using a special data-dependent quasi-linear kernel composed of the interpolation functions and the information of the local linear classifiers obtained in the first step. Moreover, the quasi-linear kernel is used as a better similarity function for the graph construction. Numerical experiments on various real-world datasets demonstrate the effectiveness of the proposed method.

Original languageEnglish
JournalIEEJ Transactions on Electrical and Electronic Engineering
DOIs
Publication statusAccepted/In press - 2018 Jan 1

Fingerprint

Classifiers
Support vector machines
Labels
Clustering algorithms
Interpolation
Experiments

Keywords

  • coarse-to-fine classification
  • DBSCAN clustering
  • Laplacian SVM
  • quasi-linear kernel composition
  • semisupervised learning

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

Cite this

@article{211a0524c5fd484fa585ed898e7e8843,
title = "A coarse-to-fine two-step method for semisupervised classification using quasi-linear Laplacian SVM",
abstract = "This paper proposes a two-step method to construct a nonlinear classifier based on semisupervised learning in a coarse-to-fine way. In the first step, a recursive density-based spatial clustering of applications with noise clustering algorithm is first introduced to find a group of density clusters, each of which contains only one kind of class labels. An SK algorithm is then applied to pairs of density clusters containing different class labels to find a set of local linear classifiers, which forms a coarse nonlinear separating boundary crossing the low-density areas by interpolating the local linear classifiers. In the second step, a Laplacian support vector machine (LapSVM) formulation based on graph construction is applied to further implicitly optimize the parameter set of the nonlinear coarse classifier. As a result, the fine-tuned nonlinear classifier is constructed in exactly the same way as a standard LapSVM, using a special data-dependent quasi-linear kernel composed of the interpolation functions and the information of the local linear classifiers obtained in the first step. Moreover, the quasi-linear kernel is used as a better similarity function for the graph construction. Numerical experiments on various real-world datasets demonstrate the effectiveness of the proposed method.",
keywords = "coarse-to-fine classification, DBSCAN clustering, Laplacian SVM, quasi-linear kernel composition, semisupervised learning",
author = "Bo Zhou and Weite Li and Takayuki Furuzuki",
year = "2018",
month = "1",
day = "1",
doi = "10.1002/tee.22825",
language = "English",
journal = "IEEJ Transactions on Electrical and Electronic Engineering",
issn = "1931-4973",
publisher = "John Wiley and Sons Inc.",

}

TY - JOUR

T1 - A coarse-to-fine two-step method for semisupervised classification using quasi-linear Laplacian SVM

AU - Zhou, Bo

AU - Li, Weite

AU - Furuzuki, Takayuki

PY - 2018/1/1

Y1 - 2018/1/1

N2 - This paper proposes a two-step method to construct a nonlinear classifier based on semisupervised learning in a coarse-to-fine way. In the first step, a recursive density-based spatial clustering of applications with noise clustering algorithm is first introduced to find a group of density clusters, each of which contains only one kind of class labels. An SK algorithm is then applied to pairs of density clusters containing different class labels to find a set of local linear classifiers, which forms a coarse nonlinear separating boundary crossing the low-density areas by interpolating the local linear classifiers. In the second step, a Laplacian support vector machine (LapSVM) formulation based on graph construction is applied to further implicitly optimize the parameter set of the nonlinear coarse classifier. As a result, the fine-tuned nonlinear classifier is constructed in exactly the same way as a standard LapSVM, using a special data-dependent quasi-linear kernel composed of the interpolation functions and the information of the local linear classifiers obtained in the first step. Moreover, the quasi-linear kernel is used as a better similarity function for the graph construction. Numerical experiments on various real-world datasets demonstrate the effectiveness of the proposed method.

AB - This paper proposes a two-step method to construct a nonlinear classifier based on semisupervised learning in a coarse-to-fine way. In the first step, a recursive density-based spatial clustering of applications with noise clustering algorithm is first introduced to find a group of density clusters, each of which contains only one kind of class labels. An SK algorithm is then applied to pairs of density clusters containing different class labels to find a set of local linear classifiers, which forms a coarse nonlinear separating boundary crossing the low-density areas by interpolating the local linear classifiers. In the second step, a Laplacian support vector machine (LapSVM) formulation based on graph construction is applied to further implicitly optimize the parameter set of the nonlinear coarse classifier. As a result, the fine-tuned nonlinear classifier is constructed in exactly the same way as a standard LapSVM, using a special data-dependent quasi-linear kernel composed of the interpolation functions and the information of the local linear classifiers obtained in the first step. Moreover, the quasi-linear kernel is used as a better similarity function for the graph construction. Numerical experiments on various real-world datasets demonstrate the effectiveness of the proposed method.

KW - coarse-to-fine classification

KW - DBSCAN clustering

KW - Laplacian SVM

KW - quasi-linear kernel composition

KW - semisupervised learning

UR - http://www.scopus.com/inward/record.url?scp=85055593852&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85055593852&partnerID=8YFLogxK

U2 - 10.1002/tee.22825

DO - 10.1002/tee.22825

M3 - Article

AN - SCOPUS:85055593852

JO - IEEJ Transactions on Electrical and Electronic Engineering

JF - IEEJ Transactions on Electrical and Electronic Engineering

SN - 1931-4973

ER -