분류나무와 결측치

곽영훈,김지현 崇實大學校 生産技術硏究所 2001 論文集 Vol.31 No.-

There are many statistical method for classification or discriminant analysis. The classification tree is one of them. There are several algorithms for classification tree. In this paper a comparison study is done of the performance of those algorithms for classification tree when we have missing values in predictors at hand. With the misclassification error rate as a performance measure, different algorithms are compared for different patterns of missing values.

회분식 반응기에서 ABS 수지의 열분해특성에 관한 연구

김지태,곽현,류한영,배성렬 漢陽大學校 工學技術硏究所 2002 工學技術論文集 Vol.11 No.-

본 연구는 앞으로 폐플라스틱 뿐 아니라 다른 폐기물에도 보편화될 것으로 예상되는 열분해공정을 이용하여 ABS 수지(Acrylonitrile-Butadiene-Styrene resign)에 대해 열분해 실험을 행하였다. 교반기가 달린 회분식 반응기에서 5대범용수지(PS, PP, PE, PVC, ABS)중 전기부품과 자동차 부품 등으로 많이 사용되고 있는 ABS 수지 100g을 400, 420, 440℃ 의 분해온도에서 등온 열분해실험을 행하였다. 대부분 고분자의 열분해 반응은 1차이므로 1차반응으로 가정하고 속도록적 해석과 함께 활성화에너지를 구하였다. 실험변수인 분해온도가 오일, 가스 및 잔류물질의 수율과 오일 생성물의 성분분포에 미치는 영향을 관찰하였다. 분해온도에 따라 약간의 차이가 나긴 하지만 주성분은 styrene, benzenebutanenitrile, ethylbenzene 등의 성분으로 이루어져 있었고, 생성오일의 양은 분해 온도가 높을수록 증가했으며, 부가가치가 큰 styrene 단량체 역시 400℃ 일 경우 32.6wt%였으나 440℃일 경우 45.8wt%까지 크게 증가하였다. Isothermal pyrolysis experiment was performed on ABS resign 100g in batch reactor. The temperature was varied from 400℃ to 440℃ at intervals of 20℃. Because most plastic degradation reaction was first order, it assumed first order and elucidated the kinetics. This was the basis of characteristics analysis of ABS resign degradation mechanism. Also, the effect of temperature on the yield of oil, gas and char product change was observed, and the distribution of oil product components was observed. Main components of oil product were a little difference with degradation temperature, but they consist of styrene, benzenebuttanenitrile, ethylbenzene etc. and their yield increased along with degradation temperature. Particularly, high value added styrene yield 32.6wt% at 400℃ but increased to 45.8wt% at 440℃.

피아노 영재성의 개념과 계발 방향의 탐색

이신동,곽지현 순천향대학교 인문과학연구소 2007 순천향 인문과학논총 Vol.20 No.-

층상구조 산화물 Na_(x)Co_(x/2)Ti_(1-x/2)O₂(0.66≤x≤1)의 합성 및 결정화학 연구

신유주,곽지현 가톨릭대학교 자연과학연구소 1997 자연과학논문집 Vol.18 No.-

층상구조 산화물 Na_(x)Co_(x/2)Ti_(1-x/2)O₂(0.66≤x≤1)이 고상합성법에 의해 Ar 분위기, 950℃에서 합성되었다. 단일상 영역은 0.75≤x≤1에서 rhombohedral, x=0.66에서는 primitive hexagnonal 상으로 결정되었고, 0.66<x<0.75에서는 두 개의 상이 공존하는 상 경계가 존재하였다. 두 구조의 결정 화학적 논의가 조성과 연관되어 공유-이온 결합성을 중심으로 이루어졌다. 또한 온도에 따른 자화율 거동을 분석한 결과, 두 구조 내에서 Co^(2+) 이온은 high-spin(S=3/2; ⁴T) 상태임을 알 수 있었고, 자기적 상호 작용에 대해서도 논의되었다. Layer-type oxides Na_(x)Co_(x/2)Ti_(1-x/2)O₂(0.66≤x≤1) have been prepared for the first time by solid-state reaction by heating the appropriate mixtures of starting materials at 950℃ under Ar ambience. They exhibit two kinds of structure according to x, respectively rhombohedral one for 0.75≤x≤1, and primitive hexagonal for x=0.66. Discussion of crystal chemistry of both structure has been made mainly focused to the iono-covalency of Na-O, and correlated to the chemical composition. Magnetic susceptibility measurements confirmed the high-spin state(S=3/2; ⁴T) of Co^(2+) ions in both structures and their magnetic interactions has been also discussed.

층상구조 산화물 Na_(x)Ni_(x/2)Ti_(1-x/2)O₂의 합성과 구조적 특성

신유주,곽지현 가톨릭대학교 자연과학연구소 1998 자연과학논문집 Vol.19 No.-

층상구조 산화물 Na_(x)Ni_(x/2)Ti_(l-x/2)0₂(0.60≤X≤1.0)이 고상합성법에 의해 Ar 분위기하에서 950℃-1100℃로 가열하여 합성되었다. 단일상 영역은 0.75≤x≤1.0에서 rhombohedral(O3), 0.60≤x≤0.75에서는 primitive hexagonal 상(P2)으로 결정되었고, x<0.60은 층상구조와 함께 pruderite 구조상이 공존하는 혼합상 영역이었다. 격자상수 a는 x가 감소함에 따라 단순감소 하였고 c는 반대로 증가하는 것이 관측되었는데 이는 Ni^(2+)와 Ti^(4+) 이온 반경의 차, (Ni/Ti)O₂ 층간의 정전기적 반발력, (Ni/Ti)O_(6) 정팔면체의 trigonal distortion 정도와 관련지어 논의되었다. O3에서 P2로의 구조전이 과정은 (Ni/Ti)-O와 Na-O간 경쟁적인 공유-이온 결합성의 변화에 기인하는 것으로 이해되었다. Na_(0.67)Ni_(0.33)Ti_(0.67)O₂의 경우 Rietvelt 분석법을 이용하여 그 결정구조를 결정하였다. Layer-type oxides Na_(x)Ni_(x/2)Ti_(l-x/2)0₂(0.60≤x≤1) have been prepared for the first time by solid-state reaction by heating the appropriate mixtures of starting materials at 950℃-1100℃ under Ar ambience. Two consecutive single phases were observed, rhombohedral(03) phase for 0.75≤x≤1.0 and hexagonal one(p2) for 0.60≤x<0.75, and a mixed-phase appeared including pruderite phase with x<0.60. Lattice parameter a decrease with x, while c increases as x diminishes. Such behaviors have been discussed on the basis of the difference of ionie radii between Ni^(2+) and Ti^(4+), the electrostatic repulsion of (Ni/Ti)0₂ slabs and the evolution of trigonal distortion of (Ni/Ti)0_(6) octahedra. Structural transition from 03 to P2 has been understood due to the competitive iono-covalency between (Ni/Ti)-0 and Na-0 bonds. As for Na_(0.67)Ni_(0.33)Ti_(0.67)O, the crystal structure has been determined by the Rietveld profile-analysis method.

Acylthiocholine의 합성

정두희,이지현,박유미,정대일,곽문정,신영주 東亞大學校附設基礎科學硏究所 1998 基礎科學硏究論文集 Vol.15 No.2

Choline esters that are used with substrate of EE-AChE-catalyzed hydrolyses were synthesized by two methods. 2-Chloroethyl thiohexanoate 4a, 2-chloroethyl thioheptanoate 4c, and 2-chloroethyl thiooctanoate 4b were synthesized by treatment of hexanoyl chloride 3a, heptanoyl chloride 3c, and octanoyl chloride 3b with ethylene sulfide 2. Hexanoylthiocholine 6a and octanoylthiocholine 6b were synthesized by using 4a and 4b with trimethylamine 5. Secondly after reaction ethylene sulfide 2 with dimethyl amine 7 and acylation by acid anhydride 8, heptanoylthiocholine 6c, decanoylthiocholine 6d were synthesized by treatment of methyl iodide.

주의력결핍-과잉행동장애를 동반한 알코올 의존환자들의 특성 : 임상적/유전학적 자료분석

김붕년,손기현,전지현,곽욱환,유희정,조수철,박철수 大韓神經精神醫學會 2003 신경정신의학 Vol.42 No.3

Objectives : This study was conducted to estimate the comorbidity rate of ADHD in a group of patients with alcohol dependency and to find out the characteristics of alcoholic patients with ADHD using the diverse clinical and genetic variables. Methods : Eighty five patients with alcohol dependency were recruited from 4 mental hospitals in Kyoung-Nam and Kyoung-Ki province. For the evaluation of ADHD symptoms in both childhood and adulthood, the highly structured Diagnostic Interview Schedule for Children-IV (DISC-FV)-ADHD module was used. The various standardized scales and questionnaires were also applied to evaluate the comorbid conditions and psychopathological status. All the subjects' blood was collected and genetic study for the polymorphism of DRD2, TH, 5-HTTLPR, COMT, ALDH2 was performed. Results : 1) The comorbid rate of definite ADHD in alcoholic patients was 38% (28/85). 2) The frequency of unmarried status was significantly higher in ADHD group compared non-ADHD group. 3) The onset of pathologic drinking and auditory hallucination was significantly earlier in ADHD group than non-ADHD alcholic group. 4) In ADHD alcoholic group, antisocial behavior was more frequently reported, and the score of co-dependency scale, depression/anxiety, aggression and obsessive compulsive drinking scales were significantly higher compared to non-ADHD alcoholic group. 5) No signficant difference was found in the frequency of polymorphic alleles in COMT, DRD2, 5-HTTLPR, ALDH2, TH between ADHD and non-ADHD alcoholic group. Conclusion : In alcoholic patients, the rate of adult type ADHD was higher than expected rate in general population. The alcoholic patients with ADHD suffered from more sever degree of alcohol dependency and earlier alcohol related problems. ADHD-alcoholic group showed higher diverse comorbid psychopathology and lower marital status compared to non-ADHD-alcoholic group. No difference, however, was found in genetic data between two groups.

광주광역시 치매의 유병률과 위험인자의 도시-농촌 지역 비교

신일선,김재민,윤진상,김석재,양수진,김웅장,이승현,강순아,곽지영,이형영 大韓神經精神醫學會 2002 신경정신의학 Vol.41 No.6

연구목적 : 본 연구의 목적은 광주광역시의 도시 및 농촌 지역에 거주하는 노인에서 치매의 유병률과 위험인자를 조사하고자 하였다. 부가적으로 이 두 지역간에 치매의 유병률과 위험인자를 비교하고자 하였다. 방 법 : 광주광역시의 전형적인 도시와 농촌지역의 65세 이상의 노인(N=1,598)을 대상으로, 2단계의 역학연구를 수행하였다. 1차 선별 단계에서는 38명의 훈련된 연구보조원이 대상노인을 면담하여, 사회인구학적 특징을 조사하고 한국판 간이정신상태검사(Korean version of Mini-Mental State Examination ; MMSE-K)로 평가하였다. 2차 임상 진단 단계에서는 1차 단계에서 MMSE-K 점수가 24점 이하인 노인(N=431)을 대상으로, 전문연구팀의 임상적 평가를 통해 치매를 진단하고 원인질환별로 알쯔하이머병(Alzheimer's disease ; AD), 혈관성 치매(vascular dementia ; VaD) 및 기타 치매로 분류하였다. 대상노인에서 치매의 유병률을 측정한 후, 광주광역시 전체 노인의 연령보정 유병률을 산출하였다. 전체 대상에서 AD의 위험인자를 조사한 후, 도시와 농촌군으로 나누어 분석을 다시 시행하였다. 결 과 : 1차 및 2차 단계의 참가율은 각각 71.0%(N=1,134) 및 83.2%(N=410) 였다. 연구 참여 노인(N=1,134)에서 전체 치매, AD 및 VaD의 유병률은 최소 각각 9.7%, 5.2%, 1.8%였다. 광주광역시 전체 노인의 연령 보정 유병률은 각각 10.7%, 5.7%, 1.9%인 것으로 산출되었다. AD의 독립 위험인자는 고령, 여성, 무학이었다. 도시와 농촌에 따른 유병률의 차이는 파악되지 않았다. 그러나 AD의 위험인자는 지역에 따라 차이가 있었다. 도시 노인에게는 무학만이, 농촌 노인에게는 고령과 여성인 경우가 독립 위험인자였다. 결 론 : 광주광역시 노인에서 치매의 유병률은 높았고, 이는 국내 다른 지역에서 수행된 선행연구 결과와 유사하였다. 알쯔하이머형 치매의 위험인자는 도시와 농촌에 따라 다른 결과를 보였다. 본 연구 결과는 한국에서의 치매의 실태를 반영하며, 치매의 적절한 관리와 예방을 위해서는 지역성 특성이 고려되어야 함을 시사한다. Objectives : The purpose of this study was to investigate the prevalence rate and risk factors of dementia in an urban and a rural sample of older persons in the metropolitan Kwangju area, Republic of Korea. In addition, the prevalence rate and risk factors of dementia between the two samples were compared. Methods : A two-phase epidemiological study of residents aged 65 or over(N=1,598) was conducted in a highly developed, urban and a non-contiguous, poorly developed, rural area of metropolitan Kwangju. In the first(screening) phase, 38 trained research assistants collectively peformed in-home interviews for all participants. Detailed sociodemographic characteristics were gathered and the Korean version of Mini-Mental State Examination (MMSE-K) was administered. In the second (diagnosing) phase, diagnosis of dementia was established for those scoring 24 or less on the MMSE-K in the screening phase(N=431), and etiological types of dementia were classified to Alzheimer's disease(AD), vascular dementia(VaD) or miscellanous type by two teams of experts. Prevalence rate of dementia was determined in the participants, and age-standardized prevalence rate adjusted by age distribution in metropolitan Kwangju was estimated. For AD, the risk factors were investigated in all participants, and analyses were repeated for the urban and rural samples separately. Results : The participating rates in the first and second phases were 71.0%(N=1,134) and 83.2%(N=410), respectively. In the participants, the prevalence rates of dementia(all types), AD and VaD were 9.7%, 5.2% and 1.8%, respectively. The age-standardized prevalence rates were 10.7%, 5.7% and 1.9%, respectively. Aging, female gender and no education(complete lack of formal education) were identified as independent risk factors for AD. No difference between the urban and rural samples was observed in the prevalence rates of dementia(all types), AD and YaD. However, risk factors for AD differed between these areas. In the urban sample, no education was the only significant factor ; whereas, aging and female gender were identified as risk factors in the rural sample. Conclusion : A high prevalence rate of dementia was observed among old persons in metropolitan Kwangju, consistent with previous studies conducted in other Korean areas. The risk factor profi1es for AD differed between urban and rural settings. The results of this study reflect the current status of dementia in Korea and suggests that appropriate management and prevention strategies for dementia should be tailored toward the geographic settings.

Protective Effect of Water Extract from Cudrania Tricuspidata on Oxidative Stress-Induced Neurotoxicity

Ji Hyun Kwak,Chang Ho Jeong,Gwi Nam Choi,Ji Hye Kim,Sung Gil Choi,Ho Jin Heo 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2009 한국식품저장유통학회 학술대회 Vol.2009 No.-

Quantitative Duplex Real-Time PCR for Babesia caballi and Theileria equi

Hyun Ji Seo,Keun Ho Kim,Mi Sun Yoo,Kyu Won Kwak,Bang Hun Hyun,Yun Sang Cho 대한수의학회 2017 대한수의학회 학술대회발표집 Vol.2017 No.-