• The Korean Journal of Applied Statistics
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• v.33 no.5
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• pp.541-553
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• 2020

The receiver operating characteristic (ROC) curve is expressed as both sensitivity and specificity; in addition, some optimal thresholds using the ROC curve are also represented with both sensitivity and specificity. In addition to the sensitivity and specificity, the expected usefulness function is considered as disease prevalence and usefulness. In particular, partial the area under the ROC curve (AUC) on a certain range should be compared when the AUCs of the crossing ROC curves have similar values. In this study, partial AUCs representing high sensitivity and specificity are proposed by using sensitivity and specificity lines, respectively. Assume various distribution functions with ROC curves that are crossing and AUCs that have the same value. We propose a method to improve the discriminant power of the classification models while comparing the partial AUCs obtained using sensitivity and specificity lines.

• Child Health Nursing Research
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• v.20 no.3
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• pp.215-224
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• 2014

Purpose: This study was conducted to identify risk factors in hospitalized children, and to develop and validate a fall-risk assessment tool for hospitalized children. Methods: A retrospective chart review was performed at one university children's hospital, and an analysis was done of the characteristics of all patients who fell during a 44-month period (n=48). These patients were compared with another 149 hospitalized children who did not fall. Results: Significant predictors of falls as identified in a multivariate logistic regression analyses were age of less than 3 years old, neurological diagnosis including epilepsy, children's dependency of ADL, physical developmental delay, multiple usage of fall-risk-increasing drugs. The respective odds ratios ranged from 2.4 to 7.1 with 95% confidence interval (p<0.05). Accordingly, defining patients with either 5 risk factors as fall-prone hospitalized children provided a sensitivity of 93.6% and specificity of 16.2%. Conclusion: The results show that this tool has an acceptable level of sensitivity to assess the risk factors of fall in hospitalized children even though the specificity was low, suggesting that this tool may enable nurses to predict the risk level of childhood falls, and develop preventive strategies against pediatric falls in children's units.

• Parasites, Hosts and Diseases
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• v.33 no.2
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• pp.117-124
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• 1995

This study was performed to evaluate diagnostic sensitivity and specificity of sonography on clonorchiasis. During the 9 months from March to November 1994, sonography skin test, stool examination, and medical examination were performed to 609 volunteers of Pohang which is located along the Hyongsan-gang (Rivers and is one of well-known endemic areas of clonorchiasis. The sensitivity of sonography was either 21% if the intrahepatic ducts dilatation was assumed to be the only positive anding or 52% if the periductal echogenicity was also included as one of positive findings. The sensitivity of skin test was 62%. The sensitivity was 46% if the diagnostic criteria were arbitrarily assumed as being positive in skin test and having either sonographic findings. The sonographic finding of fusiform, non-shadowing, weakly echogenic foci in gallbladder or in billiaiy tree indicating the flukes or aggregates of flukes was not obvious in this study. The specificity of sonography was either 95% if the intrahepatic ducts dilatation was assumed to be the only positive finding or 82% if the periductal echogenicity was also included as one of positive findings. The specificity of skin test was 52%. The specificity was 90% if the diagnostic criteria was arbitrarily assumed as being positive in skin test and having either sonographic findings.

• The Korean Journal of Applied Statistics
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• v.35 no.3
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• pp.435-443
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• 2022

In this paper, using Covid-19 diagnostic data provided by the Korea Disease Control and Prevention Agency (KDCA), we examine the probability of confirmed cases and the probability of actually being confirmed when the rapid test is negative according to the sensitivity and specificity of the rapid diagnostic kit. When we know the conditional probability of confirmation given a positive test, we induce the relationship between sensitivity and specificity, and compute the actual sensitivity of the rapid diagnosis kit based on the data of KDCA.

• The Korean Journal of Applied Statistics
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• v.20 no.3
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• pp.515-530
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• 2007

Stratum-specific likelihood ratio, which is ratio of the sensitivity to 1-the specificity in each stratum of the test, could be biased if the sensitivity and specificity of diagnostic test are affected by verification bias. Therefore, the optimal cutoff point determined by biased stratum-specific likelihood ratios is incorrect. In this study, we derived adjusted stratum-specific likelihood ratios using the adjusted sensitivity and specificity, and obtained the adjusted optimal cutoff point. The influence of the verification bias on the optimal cutoff point was described through the relation between adjusted and unadjusted stratum-specific likelihood ratios.

• Communications for Statistical Applications and Methods
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• v.18 no.1
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• pp.57-69
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• 2011

Researchers are continuously trying to find innovative diagnostic tests and published articles are accumulating at an enormous rate in many medical fields. Meta-analysis enables previously published study results to be reviewed and summarized; therefore, an objective assessment of diagnostic tests can be done with a meta-analysis of sensitivities and specificities. Data obtained by applying two diagnostic tests to a well-defined group of diseased patients produce a pair of sensitivity and by applying the same medical tests to a group of non-diseased subjects produce a pair of specificity. The statistical tests in the meta-analysis need to consider the correlatedness of the results from two diagnostic tests applied to the same diseased and non-diseased subjects. The associations between two diagnostic test results are often found to be unequal for the diseased and non-diseased subjects. In this paper, multivariate meta-analytic methods are studied by taking into account the different associations between correlated variables. On the basis of Monte Carlo simulations, we evaluate the performance of the multivariate meta-analysis methods proposed in this paper.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2002.11a
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• pp.143-143
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• 2002

돼지 장염 바이러스를 동시에 감별 진단할 수 있는 새로운 진단법인 oligonicleotide microarray 기법을 돼지 설사 분변을 대상으로 바이러스 감염을 진단하고 기존의 진단법으로 널리 사용되고 있는 RT-PCR과 진단기법의 민감도와 특이도를 비교하고자 하였다. 32개 양돈장, 102 예의 포유 및 이유자돈의 설사분변에서 microarray를 이용한 검사결과 Transmissible gastroenteritis virus (TGEV) 9.8％, porcine epidemic diarrhea virus (PEDV) 28％, (porcine enteric calicivirus (PECV) 18.6％, porcine rotavirus (PRV) group A 6.9％, PRY group C 1％ 의 검출률을 확인하였다. 또한 RT-PCR 기법과의 비교에서도 100％의 민감도와 72.2％의 특이도를 보였으며 agreement는 85.3％, kappa value 0.71로 우수한 진단기법임을 확인하였다. 이를 통해 microarray 진단법은 RT-PCR 후의 전기영동 과정과 민감도를 높이기 위해 수행되는 nested PCR 수행의 번거러움을 없애면서 정확한 감별진단을 수행할 수 있는 진단 기법임을 확인하였다.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.103-103
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• 1993

Fine needle aspiration biopsy(FNAB) is widely used in screening of head and neck(H&N) masses because it has high accuracy and few damage. The 235 cases of FNAB were performed on patient with H&N mass at the Department of Otolaryngology, Hanyang University Hospital during 1 years, from March 1985 to February 1992. The 188 of 235 were proven histologically, clinically. The results obtained were as follows ; 1) FNAB for malignant H&N mass shows sensitivity of 81.5% specificity of 96.8%. 2) FNAB for malignant LN shows sensitivity of 86.0%, specificity of 88.9%. 3) FNAB for salivary gland shows sensitivity of 66.7%, specificity 81.8%. 4) FNAB for soft tissues, bone, and intraoral lesions shows sensitivity of 90%, specificity 95.8%. 5) FNAB for tuberculosis shows false negative of 55.2%. 6) The result of FNAB was not closely related with location or size of neck nodes.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.265-267
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• 2005

최근 포유동물의 유전체에는 알려진 것보다 훨씬 많은 RNA 전사체가 발현되고 있음이 밝혀지고 있으며, 그 중에 많은 부분이 non-coding RNA로 알려지고 있다. 세포 내에서 non-coding RNA의 기능이 훨씬 다양해지고, 중요해지고 있는 상황에서 새로운 non-coding RNA를 정의하고, 탐색하는 것은 가장 시급한 과제이다. 본 연구에서는 이전 연구에서 RNA 공통 구조 학습을 위해 제안되었던, esRCSG (evolutionary search for RNA common-structural grammar) 알고리즘의 성능 향상을 위해, committee machine을 도입한다. Committee machine은 마지막 세대에서 최적화된 RNA 공통 구조 기술자 (RCSD)와 차상위로 최적화된 기술자들 중 양성데이터와 음성데이터의 치역을 합쳤을 때 특이도는 거의 변화가 없으면서 민감도의 증가가 가장 큰 기술자들의 집합이다. Committee machine은 특히 family type의 서열의 가진 특정 ncRNA에서 좋은 성능 향상을 보인다. microRNA를 이용한 성능평가에서 특이도의 변화가 거의 없이 민감도의 성능이 약 1.5배 향상되는 결과를 보였다. 이러한 특이도와 민감도가 높은 기술자를 이용함으로써 새로운 non-coding RNA를 예측하는 것을 약속할 수 있을 것이다.

• Tuberculosis and Respiratory Diseases
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• v.47 no.6
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• pp.747-756
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• 1999

Background: Acid-fast stain and cultures for diagnosis of pulmonary tuberculosis are primary and essential method, but have their limitation : low sensitivity and time consuming. The objective of this study is comparison of amplified Mycobacterium tuberculosis direct test(MTD) by the conventional AFB smears and cultures in the detection of Mycobacterium tuberculosis in respiratory specimens. Methods: During the period between November, 1997 and May, 1998 a total of 267 respiratory specimens (sputum 173, bronchial washing 94) from 187 patients suspected pulmonary tuberculosis were subjected to AFB smears, cultures and MID test. MID is based on nucleic acid amplification. We compared the MID with 3% Ogawa culture method. In positive AFB smear and negative MID specimen, positive culture identification between nontuberculous mycobacterium and M.tuberculosis was assesed by using Accuprobe M.tuberculosis complex probe. In negative AFB smear and negative AFB culture, MTD results are assessed by clinical follow-up. Results : 1) Compared with culture in sputum and bronchial fluid specimens, sensitivity and specificity of MTD in positive AFB smear is 79.7% and 20.0%, sensitivity and specificity of MTD in negative AFB smear specimens is 75.0% and 79.7%. 2) Discrepant analysis is assessed by clinical follow-up and other specimen results beyond study. Culture negative but MTD positive specimens were proved to be true positive and gave MTD sensitivity 79.2%, specificity of 84.4%, positive predictive value 80.5% and negative predictive value 83.2%. 3) 14 out of 31 specimens in negative AFB smear, negative AFB culture and positive MTD showed pulmonary tuberculosis diagnosed on clinical follow-up and sensitivity is 45.2%. 4) 2 out of 13 specimens in positive AFB smear, positive AFB culture and negative MID diagnosed as non tuberculous mycobacterium by Accuprobe culture. Conclusion: This study suggested that MID in respiratory specimens is simple and rapid diagnostic method, but considered adjuvant method rather than replace the conventional AFB smear and culture.