서포트 벡터 기계에서 잡음 영향의 효과적 조절

김철응,윤민,Kim, Chul-Eung,Yoon, Min 한국통계학회 2003 응용통계연구 Vol.16 No.2

서포트 벡터 기계(Support Vector Machines, SVMs)에서의 일반화 오차의 경계는 훈련점들과 분리 초평면 사이의 최소의 거리에 의존한다. 특히, 소프트 마진 알고리즘은 목표 마진과 slack 벡터의 놈들에 의하여 경계가 결정된다. 이 논문에서는, 자료들에 있어서 잡음들에 의한 오염들을 직접적으로 고려하는 새로운 소프트 마진 알고리즘을 공식화하였다. 그리고, 수치적 예제를 통하여, 제안된 방법과 기존의 소프트 마진 알고리즘을 비교하였다. Support Vector Machines (SVMs) provide a powerful performance of the learning system. Generally, SVMs tend to make overfitting. For the purpose of overcoming this difficulty, the definition of soft margin has been introduced. In this case, it causes another difficulty to decide the weight for slack variables reflecting soft margin classifiers. Especially, the error of soft margin algorithm can be bounded by a target margin and some norms of the slack vector. In this paper, we formulate a new soft margin algorithm considering the bound of corruption by noise in data directly. Additionally, through a numerical example, we compare the proposed method with a conventional soft margin algorithm.

안구운동과 정신분열병

김철응,Kim, Chul-Eung 대한수면의학회 1996 수면·정신생리 Vol.3 No.1

Eye movement dysfunction has been found in large numbers of schizophrenia patients and their first-degree relatives and can be studied without the interference of deficits in attention, motivation, clinical status and medication effects with relatively easy method. Eye movement dysfunction has been proposed as a useful way of expanding the schizophrenia phenotype in genetic studies. I review the literature on eye movement dysfunction with respect to syndrome and familial specificity and the quantitative assessment of eye tracking. I hope that the etiology and the pathophysiology of schizophrenia can be clarified through this eye movement study.

An Algorithm for Hannan and Rissanen's ARMA Modeling Method

김철응(Chul Eung Kim),최병선(Byoung Seon Choi) 한국통계학회 1995 Communications for statistical applications and me Vol.2 No.2

A Levinson-Type Predicipation Algorithm of a Single-Input Single-Output System

김철응(Chul Eung Kim),최병선(Byoung Seon Choi) 연세대학교 경제연구소 1995 延世經濟硏究 Vol.2 No.2

An Algorithm to Calculate the AR Parameters of a Mixed ARMA Model through the Extended Yule-Walker Equations

김철응(Chul Eung Kim),최병선(Byoung Seon Choi) 연세대학교 경제연구소 1996 延世經濟硏究 Vol.3 No.1

정신분열병 환자에서 Clozapine과 그 대사물들의 혈장농도 및 FMO3 유전자 변이

이경훈,김철응,Lee, Kyung-Hoon,Kim, Chul Eung 대한생물정신의학회 2006 생물정신의학 Vol.13 No.3

Objective : The relationship between the total daily dose of clozapine given and the plasma concentrations of clozapine and its metabolites(N-desmethylclozapine and clozapine N-oxide) and the effect of Glu158Lys (wild-type : Glu, 'H' ; variant : Lys, 'h') and Glu308Gly(wild-type : Glu, 'D' ; variant : Lys, 'd') variation in FMO3 gene on plasma concentrations of clozapine and its metabolites was studied in schizophrenic patients. Methods : Trough plasma concentrations of clozapine and its metabolites were measured in 34 schizophrenic patients receiving clozapine. The genetic variation of 'h' and 'd' in FMO3 were analyzed in 21 among 34 patients. Results : A linear relationship between the total daily dose of clozapine given(mg/kg body weight per day) and the plasma concentrations(nM) of clozapine was revealed by regression analysis(p<0.001) in the 23 patients receiving a constant daily dose of clozapine for 8 days. The plasma molar concentration ratios of clozapine N-oxide/clozapine in 8 subjects with 'hh' or 'Hh' alleles were not different from those in 6 subjects with 'HH' alleles and the plasma molar concentration ratios in 6 subjects with 'dd' or 'Dd' alleles were not different from those in 8 subjects with 'DD' alleles. Conclusion : The effect of Glu158Lys and Glu308Gly variation in FMO3 gene on clozapine metabolism could not be shown.

다양한 마취하 용량에서 케타민에 의해 유발된 청소년기 및 성체 마우스의 행동학적 변화

최형준,임수정,박해리,이성미,김철응,류승형,Choi, Hyung Jun,Im, Soo Jung,Park, Hae Ri,Lee, Seong Mi,Kim, Chul-Eung,Ryu, Seunghyong 대한생물정신의학회 2020 생물정신의학 Vol.27 No.1

Objectives Ketamine has been reported to have antidepressant effects or psychotomimetic effects. The aim of this study was to investigate the behavioral effects of ketamine treatment at various sub-anesthetic doses in adolescent and adult naïve mice. Methods In each experiment for adolescent and adult mice, a total of 60 male Institute of Cancer Research mice were randomly divided into 6 groups, which were intraperitoneally treated with physiological saline, 10, 20, 30, 40, and 50 mg/kg ketamine for consecutive 3 days. At 1 day after last injection, the locomotor and depressive-like behaviors were evaluated in mice, using open field test (OFT) and forced swim test (FST), respectively. Results In case of adolescent mice, ketamine dose was negatively correlated with total distance traveled in the OFT (Spearman's rho = -0.27, p = 0.039). In case of adult mice, we found significant positive correlation between ketamine dose and duration of immobility in the FST (Spearman's rho = 0.45, p < 0.001). Immobility time in the 50 mg/kg ketamine-treated mice was significantly higher compared to the saline-treated mice (Dunnett's post-hoc test, p = 0.012). Conclusions We found that the repeated treatment with ketamine could decrease the locomotor or prolong the duration of immobility in mice as the dose of ketamine increased. Our findings suggest that sub-anesthetic doses of ketamine might induce schizophrenia-like negative symptoms but not antidepressant effects in naïve laboratory animals.

한국판 상태-특성 분노표현척도를 이용한 한국 청소년의 분노 평가 및 우울과의 관계

김희연(Hee-Yun Kim),이명훈(Myung-Hoon Lee),배재남(Jae-Nam Bae),김철응(Chul-Eung Kim),유희정(Hee Jeong Yoo),이정섭(Jeong-Seop Lee) 대한소아청소년정신의학회 2015 소아청소년정신의학 Vol.26 No.4

Objectives:The purpose of this study was to assess anger of middle school adolescents in an urban community using State-Trait Anger Expression Inventory (STAXI)-Korean and Korean Child Behavior Checklist (K-CBCL), and to determine whether specific anger expression of adolescents is associated with certain psychopathology including depression. Methods:Data were collected from 395 middle school students and their parents in Incheon city. The students completed the STAXI, Children’s Depression Inventory, Korean version of Mood disorder Questionnaire, and Conners-Wells’ Adolescent Self-Report Scale (Short Form), and their parents completed the K-CBCL. Results:No significant correlation was observed between aggression subscale K-CBCL and each scale of the STAXI, except anger out (r=0.704). The scores for STAXI total and respective scales were significantly higher for female students than male students. A stepwise logistic regression model was used to explore the possible predictors for depression in adolescents and lower anger control and higher anger suppression were found to be predictors for depression in adolescence. Conclusion:There is a possibility of a large discrepancy between anger that the adolescents actually feel and parents’ judgment of their children’s anger. It must be considered in assessment of adolescent anger and use of further structured interviews is necessary. In addition, it may be useful to consider the anger expression style in adolescents who report depressive symptoms.

국가 치매조기검진을 통해 진단된 치매 환자의 약물치료 순응도 추적

노지현(Ji Hyun Roh),김원형(Won-Hyoung Kim),김지현(Ji-Hyun Kim),이정섭(Jeong-Seop Lee),김철응(Chul-Eung Kim),배재남(Jae-Nam Bae) 대한노인정신의학회 2015 노인정신의학 Vol.19 No.2

Objective:This study examined medication adherence rate and associated factors with medication adherence in patients who had been diagnosed as having dementia through the nationwide project for early detection of dementia in South Korea. Methods:This study enrolled a total of 131 patients, who were diagnosed as having dementia through utilization of the Kore-an version of the Consortium to Establish a Registry for Alzheimer’s Disease Assessment Packet at the Namgu Dementia Center in Incheon, from January 1, 2012 through December 31, 2012. Telephone interview was done with principal caregivers of demen-tia patients at least 18 months after they had been diagnosed. Results:Out of 131 patients, 83 caregivers of patients completed telephone interview. 62 (72.9%) patients were currently be-ing treated with antidementia drugs, and the proportion of patients being treated at the psychiatric clinic was 54.8%. Sociodemo-graphic variables and clinical rating scales included in the study had no statistically significant effect on the medication adher-ence. The most common cause of nonadherence was a misconception of dementia diagnosis and treatment (28.6%). Conclusion:The major cause of nonadherence was a misconception of dementia diagnosis and treatment, therefore, education on misconception may enhance a patient’s medication adherence. Sociodemographic variables and clinical rating scales included in the study had no statistically significant effect on the medication adherence.

정신분열병 환자에서 신체미세기형에 관한 연구

주은정,정성훈,맹소진,윤세창,김종훈,김철응,신영민,김용식,Joo, Eun-Jeong,Jeong, Seong Hoon,Maeng, So Jin,Yoon, Se Chang,Kim, Jong Hoon,Kim, Chul Eung,Shin, Youngmin,Kim, Yong Sik 대한생물정신의학회 2002 생물정신의학 Vol.9 No.2

Object and Method:Minor physical anomalies(MPAs) are frequently seen in patients with schizophrenia. MPAs are considered to arise from the anomalous development of ectoderm-originated tissues in the developing fetus. Since the central nervous system originates from ectoderm, MPAs can be regarded as externally observable and objective indicators of the aberrant development which might have taken place in the central nervous system. To investigate whether MPAs are more frequent in schizophrenic patients, the frequencies of MPAs were compared between schizophrenic patients and normal controls. Total 245 schizophrenic patients diagnosed with DSM-IV(male : 158, female : 87), and 418 normal control subjects(male : 216, female : 202) were included in this study. The MPAs were measured using the modified Waldrop scale with fifteen items in six bodily regions; head, eye, ear, mouth, hand, and foot. Result:The total scores of Waldrop scale were $4.40{\pm}1.93$($mean{\pm}standard$ deviation) in patients and $3.43{\pm}1.68$ in controls for females, and for males, $4.58{\pm}1.75$ in patients and $4.28{\pm}1.59$ in controls. For females, the excess of MPAs in schizophrenic patients was statistically significant(t-test : p<0.001). For males, schizophrenic patients also showed more MPAs than normal controls, but this tendency did not reach statistical significance (t-test : p=0.094). When the modified Waldrop total scores excluding head circumference were compared, the total scores in schizophrenic patients were significantly higher for both male and female subjects(t-test : male p<0.001, female p=0.001). The individual anomaly items included in Waldrop scale were also investigated. The items of epicanthus, hypertelorism, malformed ears, syndactylia were significantly more frequent in schizophrenic patients. In contrast, the items of adherent ear lobes, asymmetric ears, furrowed tongue, curved fifth finger, single palmar crease and big gap between toes did not show any differences in frequency between schizophrenic patients and normal controls. Since a lot of statistical analyses showed different results between male and female subjects, it seems to be necessary to consider gender as an important controlling variable for the analysis, however only the item of head circumference showed statistically significant gender-related difference according to log-linear analysis. Conclusion:With a relatively large sample size, the frequencies of MPAs enlisted in Waldrop scale were compared between schizophrenic patients and normal controls in this study. MPAs were more frequently seen in schizophrenic patients and, especially, several specific items in the Waldrop scale showed prominent excess in schizophrenic patients. Although definite conclusions cannot be drawn due to the inherent limitation of the study using Waldrop scale, these results seem to support the possibility that aberrant neurodevelopmental process might be involved in the pathogenesis of schizophrenia in some of the patients.