Journal of the Korean Data and Information Science Society

The Korean Data and Information Science Society (한국데이터정보과학회)
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Functional clustering for clubfoot data: A case study

클럽발 자료를 위한 함수적 군집 분석: 사례연구

  • Lee, Miae (Credit Planning Team, Lotte Card) ;
  • Lim, Johan (Department of Statistics, Seoul National University) ;
  • Park, Chungun (Department of Mathematics, Kyonggi University) ;
  • Lee, Kyeong Eun (Department of Statistics, Kyungpook National University)
  • Received : 2014.06.27
  • Accepted : 2014.08.27
  • Published : 2014.09.30
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Abstract

A clubfoot is a kind of congenital deformity of foot, which is internally rotated at the ankle. In this paper, we are going to cluster the curves of relative differences between regular and operated feet. Since these curves are irregular and sparsely sampled, general clustering models could not be applied. So the clustering model for sparsely sampled functional data by James and Sugar (2003) are applied and parameters are estimated using EM algorithm. The number of clusters is determined by the distortion function (Sugar and James, 2003) and two clusters of the curves are found.

클럽발은 발이 안쪽으로 굽어있는 상태로 태어나는 선천적인 발 기형의 일종이다. 본 연구에서는 한 쪽 클럽발 환자들의 수술 후 시간에 따른 양 쪽 발의 상대적인 차이 커브들을 군집분석 하려고 한다. 관측값들이 일정하지 않은 (irregular) 시점에서 희박하게 (sparsely) 관측되어서 일반적인 함수적 군집모형을 사용할 수 없어 James와 Sugar (2003) 가 제안한 희박한 자료의 함수적 군집 모형 (functional clustering model)을 이용하여 모수들을 추정하였다. 그리고 Sugar와 James (2003)의 왜곡함수 (distortion function)를 이용하여 군집의 수를 결정하여 군집분석하여 두 개의 군집을 발견하였다.

Keywords

References

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