• Title/Summary/Keyword: Neighborhood Approximations

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A Diagnostic Feature Subset Selection of Breast Tumor Based on Neighborhood Rough Set Model (Neighborhood 러프집합 모델을 활용한 유방 종양의 진단적 특징 선택)

  • Son, Chang-Sik;Choi, Rock-Hyun;Kang, Won-Seok;Lee, Jong-Ha
    • Journal of Korea Society of Industrial Information Systems
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    • v.21 no.6
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    • pp.13-21
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    • 2016
  • Feature selection is the one of important issue in the field of data mining and machine learning. It is the technique to find a subset of features which provides the best classification performance, from the source data. We propose a feature subset selection method using the neighborhood rough set model based on information granularity. To demonstrate the effectiveness of proposed method, it was applied to select the useful features associated with breast tumor diagnosis of 298 shape features extracted from 5,252 breast ultrasound images, which include 2,745 benign and 2,507 malignant cases. Experimental results showed that 19 diagnostic features were strong predictors of breast cancer diagnosis and then average classification accuracy was 97.6%.

The Use of Generalized Gamma-Polynomial Approximation for Hazard Functions

  • Ha, Hyung-Tae
    • The Korean Journal of Applied Statistics
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    • v.22 no.6
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    • pp.1345-1353
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    • 2009
  • We introduce a simple methodology, so-called generalized gamma-polynomial approximation, based on moment-matching technique to approximate survival and hazard functions in the context of parametric survival analysis. We use the generalized gamma-polynomial approximation to approximate the density and distribution functions of convolutions and finite mixtures of random variables, from which the approximated survival and hazard functions are obtained. This technique provides very accurate approximation to the target functions, in addition to their being computationally efficient and easy to implement. In addition, the generalized gamma-polynomial approximations are very stable in middle range of the target distributions, whereas saddlepoint approximations are often unstable in a neighborhood of the mean.