• Communications for Statistical Applications and Methods
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• v.3 no.2
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• pp.129-138
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• 1996

We propose a smoothing estimator of mean residual life function based on Ghorai and Susarla's (1990) smooth estimator of distribution function under random censorship model and provide the asymptotic properties of this estimator. The Monte Carlo simulation is performed to compare the proposed estimator with the other estimators and an exmple is also given using the real data.

• Bulletin of the Korean Mathematical Society
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• v.37 no.1
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• pp.127-134
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• 2000

Let $\Omega$ be a bounded pseudoconvex domain in$C^{n}$ with smooth defining function r and let$z_0\; {\in}\; b{\Omega}$ be a point of finite type. We also assume that $\Omega$ is convex in a neighborhood of $z_0$. Then we prove that all the holomorphic sectional curvatures of the Bergman metric of $\Omega$ are bounded below by a negative constant near $z_0$.

• Communications of the Korean Mathematical Society
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• v.26 no.2
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• pp.305-320
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• 2011

The relations among various types of continuity of fuzzy proper function on a fuzzy set and at fuzzy point belonging to the fuzzy set in the context of $\v{S}$ostak's I-fuzzy topological spaces are discussed. The projection maps are defined as fuzzy proper functions and their properties are proved.

• Korean Journal of Biological Psychiatry
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• v.25 no.4
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• pp.101-109
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• 2018

Objectives According to previous studies, the Chromogranin B (CHGB) gene could be an important candidate gene for schizophrenia which is located on chromosome 20p12.3. Some studies have linked the polymorphism in CHGB gene with the risk of schizophrenia. Meanwhile, smooth pursuit eye movement (SPEM) abnormality has been regarded as one of the most consistent endophenotype of schizophrenia. In this study, we investigated the association between the polymorphisms in CHGB gene and SPEM abnormality in Korean patients with schizophrenia. Methods We measured SPEM function in 24 Korean patients with schizophrenia (16 male, 8 female) and they were divided according to SPEM function into two groups, good and poor SPEM function groups. We also investigated genotypes of polymorphisms in CHGB gene in each group. A logistic regression analysis was performed to find the association between SPEM abnormality and the number of polymorphism. Results The natural logarithm value of signal/noise ratio (Ln S/N ratio) of good SPEM function group was $4.19{\pm}0.19$ and that of poor SPEM function group was $3.17{\pm}0.65$. In total, 15 single nucleotide polymorphisms of CHGB were identified and the genotypes were divided into C/C, C/R, and R/R. Statistical analysis revealed that two genetic variants (rs16991480, rs76791154) were associated with SPEM abnormality in schizophrenia (p = 0.004). Conclusions Despite the limitations including a small number of samples and lack of functional study, our results suggest that genetic variants of CHGB may be associated with SPEM abnormality and provide useful preliminary information for further study.nwhile, smooth pursuit eye movement (SPEM) abnormality has been regarded as one of the most consistent endophenotype of schizophrenia. In this study, we investigated the association between the polymorphisms in CHGB gene and SPEM abnormality in Korean patients with schizophrenia. MethodsZZWe measured SPEM function in 24 Korean patients with schizophrenia (16 male, 8 female) and they were divided according to SPEM function into two groups, good and poor SPEM function groups. We also investigated genotypes of polymorphisms in CHGB gene in each group. A logistic regression analysis was performed to find the association between SPEM abnormality and the number of polymorphism. ResultsZZThe natural logarithm value of signal/noise ratio (Ln S/N ratio) of good SPEM function group was $4.19{\pm}0.19$ and that of poor SPEM function group was $3.17{\pm}0.65$. In total, 15 single nucleotide polymorphisms of CHGB were identified and the genotypes were divided into C/C, C/R, and R/R. Statistical analysis revealed that two genetic variants (rs16991480, rs76791154) were associated with SPEM abnormality in schizophrenia (p = 0.004). ConclusionsZZDespite the limitations including a small number of samples and lack of functional study, our results suggest that genetic variants of CHGB may be associated with SPEM abnormality and provide useful preliminary information for further study.

• Korean Journal of Biological Psychiatry
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• v.15 no.4
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• pp.288-296
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• 2008

Objectives : We investigated the association of Val108/158Met polymorphism on catechol-O-methyl transferase(COMT) gene with smooth pursuit eye movement(SPEM) abnormality in Korean schizophrenia patients. Methods : We measured SPEM in 217 Korean schizophrenia patients(male 116, female 101) and divided them into two groups, one was a good SPEM function group and the other was a poor SPEM function group. Then we analyzed Val108/158Met polymorphism on COMT gene. We compared the differences of genotype and allele distributions of the polymorphism on COMT gene between the two groups. Results : The natural logarithm value of signal/noise ratio(Ln S/N ratio) of the good SPEM function group was $4.39{\pm}0.33$(mean${\pm}$s.d.) and that of poor SPEM function group was $3.17{\pm}0.71$. There were no statistically significant differences of age and male/female ratio between the two groups. There were no significant differences of genotype or allele distributions of the Val108/158Met polymorphism on COMT gene between the two schizophrenic groups. Conclusions : The results suggest that Val108/158Met polymorphism on COMT gene is not related to SPEM function abnormality in schizophrenia.

• Bulletin of the Korean Mathematical Society
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• v.41 no.2
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• pp.213-220
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• 2004

In this paper, we generalize the Bishop-Gromov volume comparison theorem by considering an integral bound for the part of the radial Ricci curvature which lies below a given smooth function. We also establish a compactness theorem from this result.

• Journal of applied mathematics & informatics
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• v.9 no.1
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• pp.423-431
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• 2002

In this paper, we find $n^{th}$ order wavelet derivatives of a sufficiently smooth function using biorthogonal wavelet bases and derive the order of convergence of the $n^{th}$ order wavelet derivatives.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.48.3-48.3
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• 2020

Using redshift-space distortion, I reconstruct the growth history as a smooth function using model independent methods. Assuming general relativity, I obtain the expansion history independently of the dark energy model, and test it to the supernovae data. The results are consistent with general relativity as gravity and the cosmological constant as dark energy, although interestingly negative dark energy densities are not ruled out by the data at z~0.7 to 1.

• Communications for Statistical Applications and Methods
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• v.23 no.3
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• pp.189-201
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• 2016

In survival analysis, the Nelson-Aalen estimator and Peterson estimator are often used to estimate a cumulative hazard function in randomly right censored data. In this paper, we suggested the smoothing version of the cumulative hazard function estimators using a Bezier curve. We compare them with the existing estimators including a kernel smooth version of the Nelson-Aalen estimator and the Peterson estimator in the sense of mean integrated square error to show through numerical studies that the proposed estimators are better than existing ones. Further, we applied our method to the Cox regression where covariates are used as predictors and suggested a survival function estimation at a given covariate.

• Journal of the Korea Society of Computer and Information
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• v.17 no.11
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• pp.189-196
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• 2012

This paper proposes Swap algorithm for solving Dynamic Economic Dispatch (DED) problem. The proposed algorithm initially balances total load demand $P_d$ with total generation ${\Sigma}P_i$ by deactivating a generator with the highest unit generation cost $C_i^{max}/P_i^{max}$. It then swaps generation level $P_i=P_i{\pm}{\Delta}$, (${\Delta}$=1.0, 0.1, 0.01, 0.001) for $P_i=P_i-{\Delta}$, $P_j=P_j+{\Delta}$ provided that $_{max}[F(P_i)-F(P_i-{\Delta})]$ > $_{min}[F(P_j+{\Delta})-F(P_j)]$, $i{\neq}j$. This new algorithm is applied and tested to the experimental data of Dynamic Economic Dispatch problem, demonstrating a considerable reduction in the prevalent heuristic algorithm's optimal generation cost and in the maximization of economic profit.