• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.666-669
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• 2005

본 논문에서는 3차원 형태로 체적 데이터를 효율적으로 랜더링 하기 위해서, 체적 데이터의 특징점을 추출하고 이를 이용하여 3차원 형태로 복원한다. 여기서, 3D Point(Vertext)를 이용하여 체적 데이터를 랜더링하고자 하여 체적소들에 대해 특정한 3D Points 추출하는 PEF 과정과 랜더링 과정을 담당하는 정점 변환 파이프라인 과정을 제안한다. 일반적으로, 고화질의 광선 추적 랜더링 처리의 경우 계샨량이 많아 그 만큼 랜더링 속도가 떨어져 체적에 대한 다른 ?A너링 기법들이 많이 제안되고 있지만, 본 논문은 다른 각도로의 접근하고자 하여, 기존의 광선 추적에 비해 저화질과 매끄럽지 않는 영상을 나타내지만, 추출된 데이터만 고려하기 때문에 계샨량을 많이 줄일 수 있어 처리속도가 개선되어 졌을 볼 수가 있다. 또한, 본 논문에서 기존의 광선 추적 기법에서 표현하는 회전, 절단, 축소/확대의 기능을 그대로 OpenGL을 이용하여 본 논문에서 제안한 처리 단계로 하여 3차원 랜더링 프로그램 제작 하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05a
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• pp.413-416
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• 2003

본 논문에서는 3 차원 형태로 체적 데이터를 효율적으로 랜더링 하기 위해서, 체적 데이터의 특징점을 추출하고 이를 이용하여 3차원 형태로 복원하기 위해 3D Points 추출을 위한 PEF 과정과 정적 변환 파이프라인 과정 [6,7] 을 통한 랜더링 방법을 제안한다. 기존의 광선 추적에 비해 저화질의 영상을 나타내지만, 추출된 데이터만 고려하기 때문에 계산량이 줄어들어 그만큼의 랜더링 속도가 빨라짐을 볼 수가 있다. 또한, 기존의 광선 추적 기법에서 표현하는 회전, 절단, 축소/확대의 기능을 OpenGL을 이용하여 3 차원 랜더링 프로그램으로 제작하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.202-205
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• 2007

본 논문에서는 3D 점집합으로부터 3D 메쉬를 생성하는 효율적인 기법을 소개한다. 대표적인 3D 삼각화 방법으로 3D Delaunay 삼각화 기법이 있으나 물체의 표면만을 고려한 메쉬 생성을 위한 방법으로 비효율적인 측면이 있다. 본 논문에서는 적은 계산량으로 물체의 표면 메쉬를 생성하는 기법을 소개한다. 물체의 각 영역을 분할하고 각 영역에 대해서 2D Delaunay 삼각화를 적용하여 3D 메쉬 구조를 얻는다. 3차원 점 집합에 대해 OBB를 계산하고 이를 기준으로 점집합을 다양한 각도에서 자르고 각 부분 점집합에 대해서 2D Delaunay 삼각화를 실시한다. 절단하는 각도의 간격이나 폭은 원래의 3D 점집합에서의 가장 가까운 이웃점들까지의 평균 거리를 이용하여 결정하도록 하였다. 후처리 과정으로 삼각 분할과정에서 잘못된 에지의 연결을 제거함으로써 객체의 삼각 분할 결과를 향상시킨다. 제안된 메쉬 생성 기법은 다양한 영상 기반 모델링 응용에서 효과적으로 적용될 수 있다.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.322-327
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• 2019

This study was conducted to improve the performance of automatic grafting robot using image recognition technique. The stem diameters of tomatoes and cucumber at the time of grafting were $2.5{\pm}0.3mm$ and $2.2{\pm}0.2mm$ for scions and $3.1{\pm}0.7mm$ and $3.6{\pm}0.3mm$ for rootstocks, respectively. The grafting failure was occurred when the different height between scions and rootstocks were over 4 mm and below 2 mm due to the small contact area of both cutting surface. Therefore, it was found that the height difference at the cutting surface of 3 mm is appropriate. This study also found that grafting failure was occurred when the stem diameters of both scions and rootstocks were thin. Therefore, it was suggested to use at least one stem with thicker than the average stem diameter. Field survey on the cutting angle of stems by hand were ranged from 13 to 55 degree for scions and 15 to 67 degree for rootstocks, respectively, which indicates that this could cause the grafting failure problem. However, the automatic grafting robot developed in this study rotates the seedlings 90 degree and then the stems are cut using a cutting blade. The control part of robot use all images taken from grafting process to determine the distance between a center of both ends of stem and a gripper center and then control the rotation angle of a gripper. Overall, this study found that The performance of automatic grafting robot using image recognition technique was superior with the grafting success rates of cucumber and tomato as $96{\pm}3.2%$ and $95{\pm}4%$, respectively.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1225-1238
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• 2015

In this research, we fit various survival models and conduct tests and estimation for the hazard change-point with the rectal cancer data. By the log-rank tests, at significance level ${\alpha}=0.10$, survival functions are significantly different according to the uniporter of glucose (GLUT1), clinical stage (cstage) and pathologic stage (ypstage). From the Cox proportional hazard model, the most significant covariates are GLUT1 and ypstage. Assuming that the rectal cancer data follows the exponential distribution, we estimate one hazard change-point using Matthews and Farewell (1982), Henderson (1990) and Loader (1991) methods.

• Journal of Veterinary Clinics
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• v.27 no.6
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• pp.679-685
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• 2010

Many animal models of osteoarthritis (OA) have been developed, aimed at understanding the long-term progression of OA and difficulty of identifying patients in the initial stage of the disease. In canines, coxofemoral luxation and hip dysplasia are common orthopedic ailments related to OA in the hip joint. Transecting the ligament of the head of the femur (LHF) aids in diagnosis of coxofemoral joint OA. Presently, mobility of this joint was increased by transected LHF in 10 mature, 2-3-year-old (average $2.57{\pm}0.20$ years), healthy male beagles. The animals were normally gaited 1-week post-operatively. During the experimental period, examinations including X-ray, complete blood count and serum chemistry were unremarkable. Proteomic examination revealed protein alterations in synovial fluid, with significant increases in Vitamin D-binding protein precursor (ANOVA, p < 0.004) and Kinogen-1 (ANOVA, p < 0.039). Both proteins correlated with arthritis.

• Food Science and Preservation
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• v.23 no.7
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• pp.913-922
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• 2016

The aim of this study was to develop a new salting condition that included added maltodextrin (MD) and grape seed extract (GSE) to ensure the microbiological safety and quality of salted shredded Korean cabbage. Response surface methodology (RSM) was used to analyze the effects of four independent variables (NaCl concentration, salting duration, MD concentration, and GSE concentration). The following response variables were evaluated: reduction in total aerobic bacteria, yeast, and mold counts; weight loss and salt content; and taste, texture, and overall acceptability of salted shredded Korean cabbage. The optimal salting conditions include a combination of 10.09~10.32% NaCl, 9.45~10.00% MD, and 234~300 ppm GSE in a ternary salting solution and a salting duration of 5.68~5.94 hr. This optimal combination reduced total aerobic bacterial and yeast/molds counts by 3.33 and 1.45 log CFU/g, respectively, while maintaining high sensory scores for taste, texture, and overall acceptability of the salted shredded Korean cabbage. In addition, the optimal conditions yielded more acceptable weight loss and salt content characteristics. The results suggest that use of the optimized combination of salting conditions can improve the microbiological safety and quality of salted shredded Korean cabbage used for commercial kimchi production.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.1
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• pp.83-93
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• 2016

Objectives : The Center for Epidemiologic Studies Depression scale-Revised is a recently revised scale which has been reported as a valid tool for the assessment of depressive symptoms. It encompasses cardinal symptoms of depression described in the Diagnostic and Statistical Manual of Mental disorders, fourth edition. In this study, we assessed the reliability, validity and psychometric properties of the Korean version of the CESD-R(K-CESD-R). Methods : Forty-eight patients diagnosed as major depressive disorder, dysthymia, depressive disorder NOS according to the DSM-IV criteria using Mini International Neuropsychiatric Interview and 48 healthy controls were enrolled in this study. They were assessed with K-CESD-R, K-MADRS, PHQ-9, KQIDS-SR, STAI to check cross-validation. Statistical analyses were performed using calculation of Cronbach's alpha, Pearson correlation coefficient, Principal Component Analysis, ROC curve and optimal cut-off value. Results : The Cronbach's alpha of K-CESD-R was 0.98. The total score of K-CESD-R revealed significantly high correlations with those of K-MADRS, PHQ-9, KQIDS-SR(r=0.910, 0.966 and 0.920, p<0.001, respectively). Factor analysis showed two factors account for 76.29% of total variance. We suggested the optimal cut-off value of K-CESD-R as 13 according to analysis of the ROC curve which value sensitivity and specificity both equally. Conclusions : These Results showed that the K-CESD-R could be a reliable and valid scale to assess depressive symptoms. The K-CESD-R is expected as a useful and effective tool for screening and measuring depressive symptoms not only in outpatient clinic but also epidemiologic studies.

• Korean Journal of School Psychology
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• v.15 no.3
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• pp.459-488
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• 2018

The self-report assessment has been most commonly used to estimate bullying/victimization (B/V) rates in most domestic and international prevalence studies. However, the presence of many potential biasing factors in such an assessment method, including specific operationalization/measurement strategies and testing conditions, has become an issue due to a considerable variability in reported involvement rates across studies. This study analyzed self-reported B/V involvement rates on Olweus Bullying Questionnaire (OBQ) among 690 Korean middle school students by gender and two different cut-offs (generous vs. strict cut-offs) and examined if the involvement rates were significantly varied by testing conditions such as presentation vs. omission of a precise definition of B/V, anonymous vs. non-anonymous/confidential administration, and the use of global vs. specific questions. Chi-square analyses revealed that boys displayed higher involvement rates on global measures of B/V and on items related to direct forms of B/V, with no significant gender differences on specific measures of relational B/V rates. It was also found that a global rate of bullying and specific rates of verbal B/V were 111% to 157% higher when no definition was provided. However, anonymous vs. non-anonymous administration had no significant impacts on rates of involvement, except for one item; there were also no significant differences in reported degrees of frankness and perceived confidentiality of their responses across two adminstration conditions. Finally, when involvement rates were assessed by using specific vs. global items, they were 68% to 148% higher with binominal correlations in low to moderate ranges. Findings also indicated that global items had a high specificity but a relatively low sensitivity. Implications of these findings were fully discussed for researchers and practitioners in the field of B/V assessment.

• Sleep Medicine and Psychophysiology
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• v.30 no.1
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• pp.22-27
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• 2023

Objectives: The purpose of this study was to develop a screening tool that is simple and easy to use for assessing sleep problems, including hypersomnolence, restless legs syndrome, and insomnia. We also examined the reliability and validity of this tool. Methods: We developed the Sleep Problem Screening Questionnaire (SPSQ), which consists of three sub-sections: insomnia (SPSQi), hypersomnolence (SPSQh), and restless legs syndrome (SPSQr). Subsequently, the participants, consisting of 222 patients with insomnia disorder and 78 healthy individuals, completed both the SPSQ and the comparative scale (Korean version of the Insomnia Severity Index). The analysis was then conducted using this data. Results: The SPSQ demonstrated good convergent and discriminant validity, as well as satisfactory internal consistency. A cutoff score of 6 on the SPSQi was found to be optimal for distinguishing individuals with insomnia. Conclusion: The results of this study suggest that the SPSQ is a reliable and valid tool for screening sleep problems among general adult population. However, there is a limitation as a comparison and validation with scales related to restless legs syndrome and hypersomnolence were not conducted.