• Title/Summary/Keyword: False positive

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Confidence Intervals for the Difference of Binomial Proportions in Two Doubly Sampled Data

  • Lee, Seung-Chun
    • Communications for Statistical Applications and Methods
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    • v.17 no.3
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    • pp.309-318
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    • 2010
  • The construction of asymptotic confidence intervals is considered for the difference of binomial proportions in two doubly sampled data subject to false-positive error. The coverage behaviors of several likelihood based confidence intervals and a Bayesian confidence interval are examined. It is shown that a hierarchical Bayesian approach gives a confidence interval with good frequentist properties. Confidence interval based on the Rao score is also shown to have good performance in terms of coverage probability. However, the Wald confidence interval covers true value less often than nominal level.

Plagiarism Detection Using Dependency Graph Analysis Specialized for JavaScript (자바스크립트에 특화된 프로그램 종속성 그래프를 이용한 표절 탐지)

  • Kim, Shin-Hyong;Han, Tai-Sook
    • Journal of KIISE:Software and Applications
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    • v.37 no.5
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    • pp.394-402
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    • 2010
  • JavaScript is one of the most popular languages to develope web sites and web applications. Since applicationss written in JavaScript are sent to clients as the original source code, they are easily exposed to plagiarists. Therefore, a method to detect plagiarized JavaScript programs is necessary. The conventional program dependency graph(PDG) based approaches are not suitable to analyze JavaScript programs because they do not reflect dynamic features of JavaScript. They also generate false positives in some cases and show inefficiency with large scale search space. We devise a JavaScript specific PDG(JS PDG) that captures dynamic features of JavaScript and propose a JavaScript plagiarism detection method for precise and fast detection. We evaluate the proposed plagiarism detection method with experiment. Our experiments show that our approach can detect false-positives generated by conventional PDG and can prune the plagiarism search space.

Comparison of Methods for the Detection of Anti-HBs for Hepatitis B Vaccination Program in Korea (보건예방사업을 위한 B형간염 표면항체 검사방법 비교)

  • Lee, Jeong-Nyeo;Urm, Sang-Hwa;Lee, Jong-Tae;Chun, Jin-Ho;Sohn, Hae-Sook
    • Journal of Preventive Medicine and Public Health
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    • v.33 no.2
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    • pp.226-230
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    • 2000
  • Objectives : The purpose of this study was to suggest a proper method for the detection of heaptitis B surface antibody(anti-HBs) in a screening program for hepatitis B vaccination. Methods : Sensivitity, specificity and predictive values were compared between Immunochromatographic assay (ICA) and passive hemagglutination(PHA) in 978 subjects(565 males, 413 females, 19-78 years ranging in age, mean 46.5 years old). EIA was used as a standard method for the detection of HBsAb. Results : Sensitivity in the detection of anti-HBs of PHA and ICA was 88.7%, and 94.9%, specificity was 94.3% and 96.6%, negative predictive value was 96.5%, and 98.0%, and positive predictive value was 82.3%, and 91.3%,, respectively. False negative rate(11.3%) of PHA was higher than that(5.1%) of ICA. The higher the titer of anti-HBs in EIA was, the lower the false negative rate was. There was no false negative result in the cases with $101mIU/{\beta}c$ or more in EIA Conclusion : We suggest that ICA should be the choice of screening method in the detection of anti-HBs in Hepatitis B vaccination program.

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Comparative Study of Electromyography and Hand Elevation Test in Carpal Tunnel Syndrome

  • Yun, Tae Kyoung;Kim, Deok-Yeol;Ahn, Duck Sun
    • Archives of Reconstructive Microsurgery
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    • v.24 no.1
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    • pp.13-15
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    • 2015
  • Purpose: Since the hand elevation test was first introduced by Ahn in 2001, it has been one of most performing provocative test for diagnosing carpal tunnel syndrome. Although many studies have been published on the hand elevation test, there are no study that can explain why false-negative results of hand elevation test appears in carpal tunnel syndrome patients diagnosed by electromyography (EMG) findings. Therefore we searched out whether hand elevation test is related with EMG severity. Materials and Methods: We made a retrospective study of 654 bilateral carpal tunnel syndrome patients. Among them 134 were studied which had different hand elevation test results on each hands. The paired samples t-test was used to compare the EMG severity of each group. The relationships between hand elevation test and EMG severity were examined using Pearson-product correlations. Comparing whether the frequency of false negative hand elevation were different between both hands, and whether the severity of EMG depends on which side of hand is, was evaluated with Mann-Whitney U-test. Results: Severity of EMG in positive group was moderate to severe on average, whereas mild to moderate on negative group, with significant difference statistically (p<0.001). Correlation between the hand elevation test results and EMG severity also showed significance statistically (p<0.001). Conclusion: Mild severity of EMG was found out to be the factor affecting the false results. However, EMG severity and hand elevation test shows a meaningful correlation, supporting the value of hand elevation test.

A Comparative Study on Artificial in Intelligence Model Performance between Image and Video Recognition in the Fire Detection Area (화재 탐지 영역의 이미지와 동영상 인식 사이 인공지능 모델 성능 비교 연구)

  • Jeong Rok Lee;Dae Woong Lee;Sae Hyun Jeong;Sang Jeong
    • Journal of the Society of Disaster Information
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    • v.19 no.4
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    • pp.968-975
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    • 2023
  • Purpose: We would like to confirm that the false positive rate of flames/smoke is high when detecting fires. Propose a method and dataset to recognize and classify fire situations to reduce the false detection rate. Method: Using the video as learning data, the characteristics of the fire situation were extracted and applied to the classification model. For evaluation, the model performance of Yolov8 and Slowfast were compared and analyzed using the fire dataset conducted by the National Information Society Agency (NIA). Result: YOLO's detection performance varies sensitively depending on the influence of the background, and it was unable to properly detect fires even when the fire scale was too large or too small. Since SlowFast learns the time axis of the video, we confirmed that detects fire excellently even in situations where the shape of an atypical object cannot be clearly inferred because the surrounding area is blurry or bright. Conclusion: It was confirmed that the fire detection rate was more appropriate when using a video-based artificial intelligence detection model rather than using image data.

Accuracy of FDG-PET/CT for Detection of Incidental Pre-Malignant and Malignant Colonic Lesions - Correlation with Colonoscopic and Histopathologic Findings

  • Kunawudhi, Anchisa;Wong, Alexandra K;Alkasab, Tarik K;Mahmood, Umar
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.8
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    • pp.4143-4147
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    • 2016
  • Purpose: We evaluated all PET/CTs acquired for patients without a primary diagnosis of colorectal cancer, and compared results for those who had subsequent colonoscopy within 6 months, to assess the accuracy of FDG PET/CT for detection of incidental pre-malignant polyps and malignant colon cancers. Materials and Methods: Medical records of 9,545 patients who underwent F-18 FDG PET/CT studies over 3.5 years were retrospectively reviewed. Due to pre-existing diagnosis of colorectal cancer, 818 patients were excluded. Of the remainder, 157 patients had colonoscopy within 6 months (79 males; mean age 61). We divided the colon into 4 regions and compared PET/CT results for each region with colonoscopy and histopathologic findings. True positive lesions included colorectal cancer, villous adenoma, tubulovillous adenoma, tubular adenoma and serrated hyperplastic polyp/hyperplastic polyposis. Results: Of 157 patients, 44 had incidental colonic uptake on PET/CT (28%). Of those, 25 had true positive (TP) uptake, yielding a 48% positive predictive value (PPV); 9% (4/44) were adenocarcinoma. There were 23 false positive (FP) lesions of which 4 were hyperplastic polyp, one was juvenile polyp and 7 were explained by diverticulitis. Fifty eight patients had false negative PET scans but colonoscopy revealed true pre-malignant and malignant pathology, yielding 23% sensitivity. The specificity, negiative predictive value (NPV) and accuracy were 96%, 90% and 87%, respectively. The average SUVmax values of TP, FP and FN lesions were 7.25, 6.11 and 2.76, respectively. There were no significant difference between SUVmax of TP lesions and FP lesions (p>0.95) but significantly higher than in FN lesions (p<0.001). The average size (by histopathology and colonoscopy) of TP lesions was 18.1 mm, statistically different from that of FN lesions which was 5.9 mm (p<0.001). Fifty-one percent of FN lesions were smaller than 5 mm (29/57) and 88% smaller than 10 mm (50/57). Conclusions: The high positive predictive value of incidental focal colonic FDG uptake of 48% for colonic neoplasia suggests that colonoscopy follow-up is warranted with this finding. We observed a low sensitivity of standardly acquired FDG-PET/CT for detecting small polyps, especially those less than 5 mm. Clinician and radiologists should be aware of the high PPV of focal colonic uptake reflecting pre-malignant and malignant lesions, and the need for appropriate follow up.

Serodiagnosis of human paragonimiasis by ELISA-inhibition test using monoclonal antibodies (단클론항체를 이용한 폐흡충증의 면역진단)

  • Yong, Tae-Sun;Seo, Jang-Hun;Yeo, In-Seok
    • Parasites, Hosts and Diseases
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    • v.31 no.2
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    • pp.141-148
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    • 1993
  • ELISA-inhibition test using Paragonimus westermani specific monoclonal antibody (Mab) was investigated to improve the diagnostic specificity of paragonimiasis. By cell fusion, one hybridoma clone secreting un-n westemanl specific Mab was selected (Pwa-14), which reacted on bands of 28 kDa, 42.5 kDa, 89 kDa and 120.5 kDa. IFA showed Pwa-14 was located at the vitelline follicles. By micro-ELISA, 100% of 22 paragonimiasis cases were found positive, but 5 of 40 clonorchlasls cases (12.5%),3 of 26 cystlcercosis cases (7.7%) showed false positive. None of 10 sparganosis patients or 28 normal controls reacted positively. On the other hand, by ELISA-Inhibition test using a R westermcni specific Mab, 100% of patagonimlasls cases were found positive, and there were no positive in cysticercosis, sparganosis cases or normal controls, except 2 (5.0%) false-positive sera of 40 clonorchiasis cases. The ELISA-Inhlbltlon test using a Mab showed higher specificity in comparison with macro-ELISA for serodlgnosis of human paragonimlasis.

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Comparison of Culture, Conventional and Real-time PCR Methods for Listeria monocytogenes in Foods

  • Kim, Dong-Hyeon;Chon, Jung-Whan;Kim, Hyunsook;Kim, Hong-Seok;Choi, Dasom;Kim, Young-Ji;Yim, Jin-Hyeok;Moon, Jin-San;Seo, Kun-Ho
    • Food Science of Animal Resources
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    • v.34 no.5
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    • pp.665-673
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    • 2014
  • We compared standard culture methods as well as conventional PCR and real-time PCR for the detection of Listeria monocytogenes (L. monocytogenes) in milk, cheese, fresh-cut vegetables, and raw beef that have different levels of background microflora. No statistical differences were observed in sensitivity between the two selective media in all foods. In total, real-time PCR assay exhibited statistically excellent detection sensitivity (p<0.05) and was less time consuming and laborious as compared with standard culture methods. Conventional culture methods showed poor performance in detecting L. monocytogenes in food with high levels of background microflora, generating numerous false negative results. While the detection of L. monocytogenes in fresh cut vegetable by culture methods was hindered only by L. innocua, various background microflora, such as L. innocua, L. welshimeri, L. grayi, and Enterococcus faecalis appeared on the two selective media as presumptive positive colonies in raw beef indicating the necessity of improvement of current selective media. It appears that real-time PCR is an effective and sensitive presumptive screening tool for L. monocytogenes in various types of foods, especially foods samples with high levels of background microflora, thus complementing standard culture methodologies.

Vision-based Vehicle Detection and Inter-Vehicle Distance Estimation (영상 기반의 차량 검출 및 차간 거리 추정 방법)

  • Kim, Gi-Seok;Cho, Jae-Soo
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.49 no.3
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    • pp.1-9
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    • 2012
  • In this paper, we propose a vision-based robust vehicle detection and inter-vehicle distance estimation algorithm for driving assistance system. We use the haar-like features of car rear-shadows, as well as the edge features for detecting of vehicles. The use of additional vehicle edge features greatly reduces the false-positive errors in the vehicle detection. And, after analyzing the conventional two inter-vehicle distance estimation methods: the location-based and the vehicle width-based, an improved inter-vehicle distance estimation algorithm which has the advantage of both method is proposed. Several experimental results show the effectiveness of the proposed method.

Warning Classification Method Based On Artificial Neural Network Using Topics of Source Code (소스코드 주제를 이용한 인공신경망 기반 경고 분류 방법)

  • Lee, Jung-Been
    • KIPS Transactions on Computer and Communication Systems
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    • v.9 no.11
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    • pp.273-280
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    • 2020
  • Automatic Static Analysis Tools help developers to quickly find potential defects in source code with less effort. However, the tools reports a large number of false positive warnings which do not have to fix. In our study, we proposed an artificial neural network-based warning classification method using topic models of source code blocks. We collect revisions for fixing bugs from software change management (SCM) system and extract code blocks modified by developers. In deep learning stage, topic distribution values of the code blocks and the binary data that present the warning removal in the blocks are used as input and target data in an simple artificial neural network, respectively. In our experimental results, our warning classification model based on neural network shows very high performance to predict label of warnings such as true or false positive.