• 한국정밀공학회지
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• 제26권2호
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• pp.118-125
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• 2009

This paper reports the size classification of nanoparticles as well as electrical tuning techniques for the cut-off diameter and collection efficiency. Classifying particles < 100 nm in diameter is quite a technical challenge using a virtual impactor with the cut-off diameter being determined geometrically. However, the proposed virtual impactor can classify particles <100 nm and tune the cut-off diameter by electrically accelerating the particles. The cut-off diameter of the proposed device was tuned from 15 to 50nm.

• 한국방사선학회논문지
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• 제13권2호
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• pp.201-207
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• 2019

본 연구는 갑상샘 초음파에서 K-TIRADS 분류와 K-TIRADS 분류에 따른 Different risk group의 조합을 이용한 방법이 양성과 악성 결절의 감별진단에 유용한지를 평가하였다. 갑상샘 초음파를 시행한 210명을 대상으로 하였으며, 세침흡인세포검사 결과를 바탕으로 후향적인 분석을 하였다. 갑상샘 결절의 양성과 악성에 따른 K-TIRADS와 Different risk group의 점수체계의 차이 분석은 카이제곱 검정을 하였다. ROC 곡선 분석을 통해 악성 결절의 예측을 위한 K-TIRADS 점수와 Different risk group의 최적 cut off 값을 결정하였다. 양성과 악성 결절 군의 분류에 따른 K-TIRADS와 Different risk group의 차이검증 결과에서 각각 통계적으로 유의한 차이를 보였다(p=.001). ROC 곡선 분석에서 양성과 악성 결절의 예측을 위한 K-TIRADS에 따른 점수분류에서는 AUC 0.786, Cut-off value> 2를 나타내었으며, Different risk group에서는 AUC 0.640, Cut-off value> 2로 결정되었다(p=.001). 갑상샘 초음파에서 결절을 발견했을 때 양성과 악성 갑상샘 결절을 감별하는 데 도움을 주는 K-TIRADS에 따른 분류체계가 Different risk group에 따른 분류체계보다 갑상샘 결절의 감별진단에 도움을 줄 것으로 생각하며 K-TIRADS에 따른 분류체계를 적용하면, 불필요한 세포 검사를 줄일 수 있고, 악성 결절의 조기발견에 도움이 될 것으로 생각된다.

• 조명전기설비학회논문지
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• 제25권12호
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• pp.21-26
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• 2011

This is a study to establish regulations against light pollution for lighting on roads. Many kinds of light pollution by luminaire on roads was calculated and analyzed by applying the classification method of luminaires(Cut-off classification of IDA-IESNA, BUG Rating Classification) and the calculation method of Upward Lighting Ratio of CIE among measures to prevent light pollution that international lighting organizations suggest. As a result of the analysis, it was found that the regulation by Cutoff of IESNA and ULR classification of CIE could be one for scattered light of light pollution compared to BUG classification but is not sufficient for the regulation of light tresspass or glare. BUG classification by each lighting zone was suggested as threshold value of the light pollution regulation considering domestic conditions.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제22권2호
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• pp.81-88
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• 2011

Objectives : This study examined the reliability and validity of the Korean version of Asperger Syndrome Diagnostic Scale (K-ASDS), to calculate the cut-off score in the diagnosis of Asperger syndrome. Further, we examined classification error rate when applying cut-off scores. Methods : One hundred sixty-seven children participated in this study, including 46 with Asperger syndrome, 26 with PDD or PDD NOS, 43 with ADHD, and 52 normal children. Results : An ANCOVA demonstrated no significant differences in the K-ASDS total score between the Asperger and the PDD & PDD NOS groups. However, these groups did show significantly higher scores than the ADHD and normal groups. Among the five subscales on the K-ASDS, the Asperger group obtained significantly higher scores on the language and cognition subscales than the PDD & PDD NOS groups. Two scales were found to be useful in distinguishing the Asperger group from the PDD & PDD NOS group through a discriminant analysis. According to an analysis of ROC curve, the cut-off score on the K-ASDS for the diagnosis of PDD including Asperger syndrome was 121. Conclusion : We discussed that K-ASDS has pretty limit.

• ETRI Journal
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• 제37권3호
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• pp.541-550
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• 2015

In this paper, we propose a classification-based approach for hybridizing statistical machine translation and rulebased machine translation. Both the training dataset used in the learning of our proposed classifier and our feature extraction method affect the hybridization quality. To create one such training dataset, a previous approach used auto-evaluation metrics to determine from a set of component machine translation (MT) systems which gave the more accurate translation (by a comparative method). Once this had been determined, the most accurate translation was then labelled in such a way so as to indicate the MT system from which it came. In this previous approach, when the metric evaluation scores were low, there existed a high level of uncertainty as to which of the component MT systems was actually producing the better translation. To relax such uncertainty or error in classification, we propose an alternative approach to such labeling; that is, a cut-off method. In our experiments, using the aforementioned cut-off method in our proposed classifier, we managed to achieve a translation accuracy of 81.5% - a 5.0% improvement over existing methods.

• 한국전문물리치료학회지
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• 제23권4호
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• pp.63-70
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• 2016

Background: The Pediatric Balance Scale (PBS) and the Fullerton Advanced Balance (FAB) scale were used to assess balance function in patients with balance problem. These multidimensional clinical balance scales provide information about potential risk factors for falls. Objects: The purpose of this study was to investigate and compare the predictive properties of the PBS and FAB scales relative to fall risk in children with cerebral palsy (CP) using a receiver operating characteristic analysis. Methods: In total, 49 children with CP (boy=21, girl=28) who were diagnosed with level 1 or 2 according to the Gross Motor Function Classification System participated in this study. The PBS and FAB were performed, and verified cut-off score, sensitivity, specificity, and the area of under the curve (AUC). Results: In this study, the PBS scale was as a predictive measure of fall risk, but the FAB was not significant in children with CP. A cut-off score of 45.5 points provided optimal sensitivity of .90 and specificity of .69 on the PBS, and a cut-off score of 21.5 points provided optimal sensitivity of .90 and specificity of .62 on the FAB. Both scales showed moderately accurate of AUC with .79 and .76, respectively. Conclusion: The PBS is a useful screening tool for predicting fall risk in children with cerebral palsy, and those who score 45.5 or lower indicate a high risk for falls and are in need of balance intervention.

• 대한기계학회논문집
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• 제15권1호
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• pp.285-291
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• 1991

본 연구에서는 800 1pm인 대유량을 처리하고 공기중 1.8~4.5$\mu\textrm{m}$ 입자를 효율 적으로 선별하여 농축시키는 슬릿형 2단 가상충돌기를 설계 제작하고 그 성능이 평가 되었다. 즉, 첫째단과 둘째단에서 4.5$\mu\textrm{m}$과 1.8$\mu\textrm{m}$이 각각 50%의 효율로 분리되도록 설계되었다. 즉, 첫째단과 둘째단에서 4.5$\mu\textrm{m}$과 1.8$\mu\textrm{m}$이 각각 50%의 효율로 분리되도 록 설계한다. 설계인자(design parameter)들을 결정하기 위하여 먼저 슬릿형 노즐의 1단 가상충돌기의 분리효율(separation efficiency)에 대한 실험을 통하여 50% 커트오 프 Stokes수를 구하고, 이를 기초로 하여 2단 가상 충돌기의 주요치수와 작동조건을 결정하였다.

• Journal of the Korean Data and Information Science Society
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• 제22권4호
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• pp.619-630
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• 2011

본 연구에서는 두 분포함수의 혼합된 자료에서 적절한 분류점을 추정하고 평가하기 위하여 많이 사용하는 아홉 종류의 분류정확도 측도인 MVD, Youden지수, (0,1)까지최단기준, 수정된 (0,1)까지 최단기준, SSS, 대칭점, 정확도면적, TA, TR을 다섯 개의 조건범주로 군집시킨다. 신용평가분석에서 정상과 부도상태의 스코어 확률변수가 정규분포를 따르며 전체부도율로 혼합되었다고 가정한다. 다양한 정규혼합분포의 상황에서 군집된 측도들의 최적분류점을 발견하고, 그 분류점에 대응하는 제I종 오류율과 제II종 오류율 그리고 두 종류의 오류율 합을 구하여 각각의 오류율이 최소인 경우를 탐색적으로 살펴본다. 현실자료에 적합한 정규혼합분포를 추정하여 본 연구 결과를 적용하면 최소 오류율이 보장되는 분류정확도를 선택할 수 있으며, 이를 사용하여 모형의 판별력을 향상시킬 수 있다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제18권1호
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• pp.38-48
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• 2007

Objectives : The K-ARS (Korean ADHD Rating Scale) is one of the most important assessment tool of attention-deficit hyperactivity disorder (ADHD) in Korea. in this study, we presented detailed normative data on the K-ARS for school-aged children in Seoul metropolitan area to put it to practical use. Methods : The subjects were 2,397 students(1,223 boys and 1,174 girls, aged 6-12) from 4 elementary schools in Seoul, and one caretaker of each child completed the K-ARS for parents. Children who showed high scores of the K-ARS for parents were screened, and 2 child psychiatrists interviewed them to make a clinical diagnosis. We compared the mean scores of the K-ARS for parents between ADHD and normal group, and examined the percentage of correct classification. Results : There were some differences in score of the K-ARS for parents according to sex and age, so we presented continuous normative data with T score and subdivided cut-off points for ADHD screening. Interviews with child psychiatrists using DSM-IV criteria were performed to test diagnostic validity, and the difference in every the K-ARS for parents index between ADHD and normal group was significant(p<.001). Using 3 different cut-of points(80th, 90th, 93rd percentage), the accuracies of ADHD correct classification were 67.9, 72.2, 71.1% and all 3 canonical discriminants were significant (p<.05) between ADHD and normal group. Conclusion : The normative data and cut-off points on the K-ARS for parents are useful in screening ADHD children in Seoul metropolitan area.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
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• pp.1044-1051
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• 2002

This paper proposes a two-phase mathematical programming approach by considering classification gap to solve the proposed credit scoring problem so as to complement any theoretical shortcomings. Specifically, by using the linear programming (LP) approach, phase 1 is to make the associated decisions such as issuing grant of credit or denial of credit to applicants. or to seek any additional information before making the final decision. Phase 2 is to find a cut-off value, which minimizes any misclassification penalty (cost) to be incurred due to granting credit to 'bad' loan applicant or denying credit to 'good' loan applicant by using the mixed-integer programming (MIP) approach. This approach is expected to and appropriate classification scores and a cut-off value with respect to deviation and misclassification cost, respectively. Statistical discriminant analysis methods have been commonly considered to deal with classification problems for credit scoring. In recent years, much theoretical research has focused on the application of mathematical programming techniques to the discriminant problems. It has been reported that mathematical programming techniques could outperform statistical discriminant techniques in some applications, while mathematical programming techniques may suffer from some theoretical shortcomings. The performance of the proposed two-phase approach is evaluated in this paper with line data and loan applicants data, by comparing with three other approaches including Fisher's linear discriminant function, logistic regression and some other existing mathematical programming approaches, which are considered as the performance benchmarks. The evaluation results show that the proposed two-phase mathematical programming approach outperforms the aforementioned statistical approaches. In some cases, two-phase mathematical programming approach marginally outperforms both the statistical approaches and the other existing mathematical programming approaches.