• Title, Summary, Keyword: principal component analysis (PCA)

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Principal Component Analysis Based Two-Dimensional (PCA-2D) Correlation Spectroscopy: PCA Denoising for 2D Correlation Spectroscopy

  • Jung, Young-Mee
    • Bulletin of the Korean Chemical Society
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    • v.24 no.9
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    • pp.1345-1350
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    • 2003
  • Principal component analysis based two-dimensional (PCA-2D) correlation analysis is applied to FTIR spectra of polystyrene/methyl ethyl ketone/toluene solution mixture during the solvent evaporation. Substantial amount of artificial noise were added to the experimental data to demonstrate the practical noise-suppressing benefit of PCA-2D technique. 2D correlation analysis of the reconstructed data matrix from PCA loading vectors and scores successfully extracted only the most important features of synchronicity and asynchronicity without interference from noise or insignificant minor components. 2D correlation spectra constructed with only one principal component yield strictly synchronous response with no discernible a asynchronous features, while those involving at least two or more principal components generated meaningful asynchronous 2D correlation spectra. Deliberate manipulation of the rank of the reconstructed data matrix, by choosing the appropriate number and type of PCs, yields potentially more refined 2D correlation spectra.

Risk Evaluation of Slope Using Principal Component Analysis (PCA) (주성분분석을 이용한 사면의 위험성 평가)

  • Jung, Soo-Jung;Kim, -Yong-Soo;Kim, Tae-Hyung
    • Journal of the Korean Geotechnical Society
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    • v.26 no.10
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    • pp.69-79
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    • 2010
  • To detect abnormal events in slopes, Principal Component Analysis (PCA) is applied to the slope that was collapsed during monitoring. Principal component analysis is a kind of statical methods and is called non-parametric modeling. In this analysis, principal component score indicates an abnormal behavior of slope. In an abnormal event, principal component score is relatively higher or lower compared to a normal situation so that there is a big score change in the case of abnormal. The results confirm that the abnormal events and collapses of slope were detected by using principal component analysis. It could be possible to predict quantitatively the slope behavior and abnormal events using principal component analysis.

Utilizing Principal Component Analysis in Unsupervised Classification Based on Remote Sensing Data

  • Lee, Byung-Gul;Kang, In-Joan
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • pp.33-36
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    • 2003
  • Principal component analysis (PCA) was used to improve image classification by the unsupervised classification techniques, the K-means. To do this, I selected a Landsat TM scene of Jeju Island, Korea and proposed two methods for PCA: unstandardized PCA (UPCA) and standardized PCA (SPCA). The estimated accuracy of the image classification of Jeju area was computed by error matrix. The error matrix was derived from three unsupervised classification methods. Error matrices indicated that classifications done on the first three principal components for UPCA and SPCA of the scene were more accurate than those done on the seven bands of TM data and that also the results of UPCA and SPCA were better than those of the raw Landsat TM data. The classification of TM data by the K-means algorithm was particularly poor at distinguishing different land covers on the island. From the classification results, we also found that the principal component based classifications had characteristics independent of the unsupervised techniques (numerical algorithms) while the TM data based classifications were very dependent upon the techniques. This means that PCA data has uniform characteristics for image classification that are less affected by choice of classification scheme. In the results, we also found that UPCA results are better than SPCA since UPCA has wider range of digital number of an image.

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Hierarchically penalized sparse principal component analysis (계층적 벌점함수를 이용한 주성분분석)

  • Kang, Jongkyeong;Park, Jaeshin;Bang, Sungwan
    • The Korean Journal of Applied Statistics
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    • v.30 no.1
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    • pp.135-145
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    • 2017
  • Principal component analysis (PCA) describes the variation of multivariate data in terms of a set of uncorrelated variables. Since each principal component is a linear combination of all variables and the loadings are typically non-zero, it is difficult to interpret the derived principal components. Sparse principal component analysis (SPCA) is a specialized technique using the elastic net penalty function to produce sparse loadings in principal component analysis. When data are structured by groups of variables, it is desirable to select variables in a grouped manner. In this paper, we propose a new PCA method to improve variable selection performance when variables are grouped, which not only selects important groups but also removes unimportant variables within identified groups. To incorporate group information into model fitting, we consider a hierarchical lasso penalty instead of the elastic net penalty in SPCA. Real data analyses demonstrate the performance and usefulness of the proposed method.

An Improved Robust Fuzzy Principal Component Analysis (잡음 민감성이 개선된 퍼지 주성분 분석)

  • Heo, Gyeong-Yong;Woo, Young-Woon;Kim, Seong-Hoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.5
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    • pp.1093-1102
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    • 2010
  • Principal component analysis (PCA) is a well-known method for dimension reduction while maintaining most of the variation in data. Although PCA has been applied to many areas successfully, it is sensitive to outliers. Several variants of PCA have been proposed to resolve the problem and, among the variants, robust fuzzy PCA (RF-PCA) demonstrated promising results. RF-PCA uses fuzzy memberships to reduce the noise sensitivity. However, there are also problems in RF-PCA and the convergence property is one of them. RF-PCA uses two different objective functions to update memberships and principal components, which is the main reason of the lack of convergence property. The difference between two functions also slows the convergence and deteriorates the solutions of RF-PCA. In this paper, a variant of RF-PCA, called RF-PCA2, is proposed. RF-PCA2 uses an integrated objective function both for memberships and principal components. By using alternating optimization, RF-PCA2 is guaranteed to converge on a local optimum. Furthermore, RF-PCA2 converges faster than RF-PCA and the solutions found are more similar to the desired solutions than those of RF-PCA. Experimental results also support this.

A Multi-Resolution Distance Measure for Two Dimensional Images Using Principal Component Analysis and Independent Component Analysis (주성분분석 및 독립성분분석을 이용한 이차원 영상에서의 다중해상도 거리 측정)

  • 홍준식
    • Proceedings of the Korean Information Science Society Conference
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    • pp.247-249
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    • 2002
  • 본 논문에서는 주성분 분석(principal component analysis; 이하 PCA) 및 독립성분분석(independent component analysis; 이하 ICA)을 이용, 이차원 영상을 분류하여 다중해상도에서 영상간의 거리를 측정하여 PCA 와 ICA 중에서 어느 것이 영상간의 상대적 식별을 용이하게 하는지 모의 실험을 통하여 확인하고자 한다. 모의 실험 결과로부터, ICA가 PCA에 비하여 영상간의 상대적 식별이 용이하여 빨리 수렴이 되는 것을 모의 실험을 통하여 확인하였다.

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Global Covariance based Principal Component Analysis for Speaker Identification (화자식별을 위한 전역 공분산에 기반한 주성분분석)

  • Seo, Chang-Woo;Lim, Young-Hwan
    • Phonetics and Speech Sciences
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    • v.1 no.1
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    • pp.69-73
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    • 2009
  • This paper proposes an efficient global covariance-based principal component analysis (GCPCA) for speaker identification. Principal component analysis (PCA) is a feature extraction method which reduces the dimension of the feature vectors and the correlation among the feature vectors by projecting the original feature space into a small subspace through a transformation. However, it requires a larger amount of training data when performing PCA to find the eigenvalue and eigenvector matrix using the full covariance matrix by each speaker. The proposed method first calculates the global covariance matrix using training data of all speakers. It then finds the eigenvalue matrix and the corresponding eigenvector matrix from the global covariance matrix. Compared to conventional PCA and Gaussian mixture model (GMM) methods, the proposed method shows better performance while requiring less storage space and complexity in speaker identification.

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Face Recognition using Modified Local Directional Pattern Image (Modified Local Directional Pattern 영상을 이용한 얼굴인식)

  • Kim, Dong-Ju;Lee, Sang-Heon;Sohn, Myoung-Kyu
    • KIPS Transactions on Software and Data Engineering
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    • v.2 no.3
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    • pp.205-208
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    • 2013
  • Generally, binary pattern transforms have been used in the field of the face recognition and facial expression, since they are robust to illumination. Thus, this paper proposes an illumination-robust face recognition system combining an MLDP, which improves the texture component of the LDP, and a 2D-PCA algorithm. Unlike that binary pattern transforms such as LBP and LDP were used to extract histogram features, the proposed method directly uses the MLDP image for feature extraction by 2D-PCA. The performance evaluation of proposed method was carried out using various algorithms such as PCA, 2D-PCA and Gabor wavelets-based LBP on Yale B and CMU-PIE databases which were constructed under varying lighting condition. From the experimental results, we confirmed that the proposed method showed the best recognition accuracy.

Blind Source Separation via Principal Component Analysis

  • Choi, Seung-Jin
    • Journal of KIEE
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    • v.11 no.1
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    • pp.1-7
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    • 2001
  • Various methods for blind source separation (BSS) are based on independent component analysis (ICA) which can be viewed as a nonlinear extension of principal component analysis (PCA). Most existing ICA methods require certain nonlinear functions (which leads to higher-order statistics) depending on the probability distributions of sources, whereas PCA is a linear learning method based on second-order statistics. In this paper we show that the PCA can be applied to the task of BBS, provided that source are spatially uncorrelated but temporally correlated. Since the resulting method is based on only second-order statistics, it avoids the nonlinear function and is able to separate mixtures of several colored Gaussian sources, in contrast to the conventional ICA methods.

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