저온 결합 SiC 내화판의 치밀화

황규홍,조명제,백인찬 경상대학교 생산기술연구소 2000 生産技術硏究所論文集 Vol.16 No.-

To achieve the good densification of SiC plate at low temperature, the effect and behaviour of V2O5 added for sintering agent was studied. By adding V2O5 powder fairly good wetability between SiC particles improved densification, but V2O5 was removed toward surface after sintering. After sintering, to get a better strength, the effect of clay content was investigated. and about 0.3wt% of clay content was suitable for getting a good strength. Addition of large amount of clay and V2O5 powder was good for getting a high sintering density, but the bending was happened during liquid phase sintering so that to protect bending suitable content of clay and V2O5 powder was studied.

알레르기성 비염 환자에서 절지동물성 특이항원의 양성율 및 항원간 일치율

황규윤,남해선,박준수,권준택,백병준,김장묵,오천환,조성란 순천향의학연구소 2000 Journal of Soonchunhyang Medical Science Vol.6 No.2

The current study was designed to evaluate the positive rates of arthropod allergens by Korean inhalant panel of MAST-CLA in patients with allergic rhinitis. One hundred sixty patients, diagnosed to allergic rhinitis in an Out Patient Center of Soonchunhyang University Chunan Hopsital during Aug 1998 to July 2000, were studied. 1. The overall positive rate among 35 specific allergens was 59.4% (95 patients). 2. The arthropod related allergen accounted for 82.1% (78 patients) of the positive rate. 3. Each positive rate of Dermatophagoides farinae (Df), Dermatophagoides pteronyssinus (Dp), house dust (Hd), and cockroach mix (Cm) was 45.0% (72 patients), 43.1% (69 patients), 28.1% (45 patients), and 8.8% (14 patients), respectively. 4.Significant agreement between arthropod allergens was observer (P < 0.05). 5. The obseved agreement between Df and Dp was 95.6%, showing most significant Kappa index (Kappa = 0.911, P < 0.001). There results suggested that although MAST-CLA is a useful measure of identifying specific allergens, the specificity of two mite allergen relatively low, implying because of common allergen between mites in Korean panel of MAST-CLA. Our data also supported that arthropod is the major cause of allergen in patients with allergic rhinitis, however, the MAST-CLA should be modified in order to exclude common allergen of mite and to include more specific mite allergen.

제4경추의 형태와 초경을 통한 성숙지표에 관한 연구

이규홍,황용인,김윤지,박양호,백승학,차경석 대한치과교정학회 2008 대한치과교정학회지 Vol.38 No.1

본 연구는 측모 두부 규격 방사선사진을 이용하여 성장 중인 아동의 제4경추 형태를 경추 몸체부 하연의 만곡 정도에 따라 분류하고 초경의 시기와 수완부 골 성숙 단계를 평가하여, 성장 중인 아동의 골격적 부정교합의 진단 및 악정형 치료를 위한 성장 시기 평가에 제4경추의 형태 변화가 진단의 참고자료로 활용될 수 있는지를 연구하였다. 11-14세 여자 환자 중, 같은 날짜에 촬영된 측모 두부 규격 방사선사진과 수완부 방사선사진이 모두 있는 81명을 대상으로 환자의 측모 두부 규격 방사선사진상 제4경추 몸체부 하연의 만곡 정도에 따라 세 그룹으로 분류하였다. (Group A - 제4경추 몸체부 하연의 만곡 정도가 1.05 mm 이하, Group B -제4경추 몸체부 하연의 만곡 정도가 1.05- 2.07 mm 사이, Group C -제4경추 몸체부 하연의 만곡 정도가 2.07 mm 이상)세 그룹에서 각각 제4경추 몸체부의 수직 길이, 수평 길이, 수직/수평 비율, 초경의 시기, 수완부 골 성숙 단계를 측정한 결과 다음과 같은 결론을 얻었다. 평균 수완부 골 성숙 단계는 Group A가 SMI 5.67 ± 2.57단계, Group B는 SMI 8,73 ± 2.41 단계, Group C는 SMI 10.00 ± 1.47단계로 나타났다. GroupA에서 Group B, Group C로 갈수록 제4경추의 수직 길이, 수평 길이, 수직/수평 비율, 수완부 골 성숙 단계에 있어서 각각 유의하게 더 큰 값을 보였다. 본 연구대상 아동의 평균 초경 시기는 11.64 ± 0.92세를 보였다. 제4경추 몸체부 하연의 만곡 정도, 수직 길이, 수평 길이, 수직/수평 비율은 수완부 골 성숙 단계와 각각 서로 유의한 양의 상관관계를 나타냈다. 초경을 경험한 그룹이 초경을 경험하지 않은 그룹에 비해 제4경추의 수직 길이, 수평 길이, 수직/수평 비율, 수완부 골 성숙 단계에 있어서 유의하게 큰 값을 보였다. 연구 결과 측모 두부 규격 방사선사진상 제4경추 하연의 만곡 깊이가 2.07 mm 이상인 경우 성장의 완료 단계에 가까운 시기로 나타나 이 시기의 악정형적 치료는 큰 효과를 얻을 수 없을 것으로 사료된다. Objective: This study analyzed the morphologic changes of the fourth cervical vertebra body to determine the skeletal age of orthodontic patients during growth. Methods: Eighty-one female patients aged from 11 to 14 who had cephalograms taken on the same day were examined. The subjects were divided into three groups depending on the depth of the concavity of the lower border of the fourth cervical vertebra (Group A: less than 1.05 mm, Group B: 1.05 - 2.07 mm, Group C: greater than 2.07 mm). Menarcheal timing, SMI stage, length, width and ratio of length and width of the fourth cervical vertebra body were analyzed and the following results were obtained. Results: The average SMI stage of group A,B and C were 5.67 ± 2.57, 8.73 ± 2.41, and 10.00 ± 1.47, respectively. Length, width, ratio of length and width, and SMI stage were greater in group B than group A and in group C than group B. Mean menarcheal timing was 11.64 ± 0.92 years. Concavity depth, length, width, ratio of length and width showed a significant positive correlation with SMI stage, especially with the concavity depth. Conclusion: The results of this study propose a simple method for determining the timing of orthopedic treatment by measuring the concavity depth of the fourth cervical vertebra on the cephalogram.

새로운 단층 퍼셉트론 알고리즘

양황규,김광백 東西大學校 1997 동서논문집 Vol.3 No.1

본 논문에서는 인공 신경망과 퍼지 논리의 장점을 뉴런 구조에 적용하여 학습 속도가 빠르며 수렴률을 향상시키는 방법을 제안한다. 인공 신경망의 벤치마크로 사용되는 XOR문제, Parity문제 및 현실적인 응용을 위해 영문자 인식에 적용시켜 보았다. 실험 결과, 모든 데이터값과 목표값에 대해서 항상 수렴을 보장하는 것은 아니다. 그렇지만 학습속도가 빠르며 수렴률의 향상을 보였다. 제안된 학습 알고리즘은 임의의 층으로 확장이 가능하다. 여기서는 단층의 경우만을 고려하여 빠른 속도와 방대한 자료에 대한 빠른 처리를 가능하게 한다. In this paper, a method of improving the learning speed and convergence rate is proposed to exploit the advantages of artificial neural networks and fuzzy theory to neuron structure. This method is applied to the XOR problem, Parity problem which is used as the benchmark in neural betwork structure, and recognition of English characters for complex and practical application. As a result of experiment, it does not always guarantee the convergence. However, the network is improved the learning time and has the high convergence rate. The proposed network is able to extend the arbitrary layer. When we consider only the case of the single layer, the networks had the capability of high speed during the learning process and rapid processing on huge patterns.

알레르기 환자에서 MAST-CLA 검사의 의의

남해선,황규윤,,백병준,정윤영,오천환,조성란,박준수 순천향의학연구소;Soonchunhyang Medical Research Institute 2000 Journal of Soonchunhyang Medical Science Vol.6 No.1

To evaluate usefulness of application of MAST-CLA to indetify allergens, authors conducted MAST-CLA allergen-specific IgE assay and collected allergy related symptoms in 118 allergic patients diagnosed at Soonchunhyang University Chunan Hospital during October 1998 through January 2000. The results were as followings; 1. The mean (SD) age was 23.1 (±12.17) years old and teenagers accounted for 33.1% of patients. 2. The frequent allergic symptoms were sneezing (59.3%), rhinorrhea (53.4%), nasal stiffness (44.1%), itching sensation (24.6%), cough or sputum (16.1%), and eye symptom (8.5%) in order. 3. Among these subjects, 62.7% of patients revealed at least more than one specific allergen and 70.3% showed elevated total IgE levels by MAST-CLA. The three most frequent specific allergens were Dermatophagoides farinae (47.5%), Dermatophagoides pteronyssinus (45.8%), and house dust (30.5%). 4. While age was not significantly related to positive of both specific allergens and total IgE (P>0.05), sneezing and nasal stiffness were significantly associated with positive of specific allergen and total IgE, respectively (both P<0.05). 5. Total IgE increased with the number of specific allergens, but both specific allergen and total IgE were not significantly related to increases of allergic symptoms (P>0.05). In conclusion, our data suggest that MAST-CLA allergen-specific IgE assay is useful measure for identification of causative allergens in allergic patients, however, it is recommended that more specific allergic antigens should be determined and replaced or added to Korean inhalent panel of MAST-CLA.

퍼지논리를 이용한 자기 주도적 학습 능력과 시험 능력 평가 방법

정회인,양황규,김광백 한국컴퓨터교육학회 2004 컴퓨터교육학회 논문지 Vol.7 No.2

본 논문에서는 학습자 스스로가 학습 능력을 조절하고 학습 능력과 시험 능력을 객관적으로 판단할 수 있는 자기 주도적 학습 능력 및 시험 능력 평가 방법을 제안하였다. 제안된 자기 주도적 학습 능력 및 시험 능력 평가 방법은 삼각형 타입의 소속 함수와 퍼지 논리를 이용하여 학습 능력과 시험 능력의 소속도를 계산하고 각각에 대해 퍼지 등급도를 부여하였다. 학습 능력의 소속도와 시험 능력의 소속도에 대해서 퍼지 관계의 연산 및 합성에 의해 최종 소속도를 계산하고 퍼지 등급도를 결정하여 삭습자가 학습 능력의 소속도와 시험 능력의 소속도 및 최종 퍼지 등급도를 분석하여 스스로 학습을 조정할 수 있도록 하였다. 그리고 제안된 연구 내용을 인터넷 정보 검색사 필기 과목에 적용하여 구현하였다. In this thesis, We propose the self-directed learning and test-performing abilities assessment method to evaluate the learning and the test-performing abilities in which learners can not only control their own learning abilities for themselves, but also judge objectively learning and test-performing abilities. This method shows the membership degree of learning and test-performing abilities by using both the triangle-type membership function and the fuzzy logic. In addition, it gives the fuzzy grades to each item. The final membership degrees are calculated and the fuzzy grades are decided by the operation and composition of fuzzy relations on the membership degrees of learning and test-performing abilities. In this method, which is applicable to a writing subject for information searchers, learners are asked to analyse the membership degrees of the learning and test-performing abilities and the final fuzzy grades and to adjust a learning process for themselves.

Learning Hierarchical Bayesian Networks for Large-Scale Data Analysis

Kyu-Baek Hwang(황규백) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.10

BMB Reports : Partial AUC maximization for essential gene prediction using genetic algorithms

( Kyu Baek Hwang ),( Beom Yong Ha ),( Sang Hun Ju ),( Sang Soo Kim ) 생화학분자생물학회(구 한국생화학분자생물학회) 2013 BMB Reports Vol.46 No.1

Identifying genes indispensable for an organism`s life and their characteristics is one of the central questions in current biological research, and hence it would be helpful to develop computational approaches towards the prediction of essential genes. The performance of a predictor is usually measured by the area under the receiver operating characteristic curve (AUC). We propose a novel method by implementing genetic algorithms to maximize the partial AUC that is restricted to a specific interval of lower false positive rate (FPR), the region relevant to follow-up experimental validation. Our predictor uses various features based on sequence information, protein-protein interaction network topology, and gene expression profiles. A feature selection wrapper was developed to alleviate the over-fitting problem and to weigh each feature`s relevance to prediction. We evaluated our method using the proteome of budding yeast. Our implementation of genetic algorithms maximizing the partial AUC below 0.05 or 0.10 of FPR outperformed other popular classification methods. [BMB Reports 2013; 46(1): 41-46]

바이오데이터 분석을 위한 기계학습 기술

황규백(Kyu Baek Hwang),정제균(Je Gun Joung),남진우(Jin Wu Nam),김병희(Byoung Hee Kim),이제근(Je Keun Rhee),장병탁(Byoung Tak Zhang) 한국정보과학회 2007 정보과학회지 Vol.25 No.3

작은 데이터에 대한 베이지안망 분류기(BNC)의 베이지안 모델 평균화(BMA) 성능 평가

황규백(Kyu-Baek Hwang),장병탁(Byoung-Tak Zhang) 한국정보과학회 2003 한국정보과학회 학술발표논문집 Vol.30 No.2Ⅰ

작은 데이터에서 베이지안망 분류기 (Bayesian Network Classifier BNC)를 학습할 때, 과대적합(overfitting)으로 인한 일반화 성능의 저하가 초래된다. 이런 경우, 베이지안 모델 평균화(Bayesian model averaging, BMA)는 모델 자체에 대한 불확실성을 분석 과정에서 고함으로써, 성능 저하를 피할 수 있는 수단을 제공한다. 본 논문에서는 BNC와 BMA의 작은 데이터에 대한 성능을 평가 및 분석한다. 특히, 노드의 순서에 대한 평균화의 효과가 연구된다. 인공데이터에 대한 실험 결과, 노드의 순서가 BNC의 BMA의 분류 성능에 미치는 영향은 지대하며, 이는 데이터의 크기가 극히 작은 경우의 성능 저하에 직접적 원인이 된다.