• Title/Summary/Keyword: False-Positive

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A NEW SYSTEM OF VISUAL PRESENTATION OF ANALYSIS OF TEST PERFORMANCE: THE 'DOUBLE-RING' DIAGRAM

  • Stefadouros Miltiadis A.
    • 대한예방의학회:학술대회논문집
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    • 1994.02b
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    • pp.142-149
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    • 1994
  • Substitution of graphic representation for extensive lists of numerical statistical data is highly desirable by both editors and readers of medical journals, faced with an exploding abundance of contemporary medical literature. A novel graphic tool. the 'double-ring diagram', is described herein which permits visual representation of information regarding certain statistical variables used to describe the performance of a test or physical sign in the diagnosis of a disease. The diagram is relatively easy to construct on the basis of a number of primary data such as the prevalence and the true positive, true negative. false positive and false negative test results. These values are reflected in the diagram along with the values of other statistical variables derived from them. such as the sensitivity. specificity, predictive values for positive and negative test result. and accuracy. This diagram may be useful in visualizing a test's performance and facilitating visual comparison of performance of two or more tests.

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Data Mining based Classification Model for False Alarm rate reducing of IDS (IDS의 False Alarm 발생율 감소를 위한 데이터 마이닝 기반의 분류모델)

  • 전원용;신문선;김은희;류근호
    • Proceedings of the Korean Information Science Society Conference
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    • 2004.04a
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    • pp.247-249
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    • 2004
  • IDS에서 발생되는 경보의 수는 최근 인터넷 애플리케이션의 발달로 인하여 급격히 증가하고 있으며. 그로 인해 오 경보의 수도 함께 증가하고 있다. 발생된 경보들은 침입탐지 시스템의 성능저하와 alert flooding 의 원인이 된다. 따라서 이 논문에서는 다량의 경보 중에서 오 경보(False Alarm)의 발생을 감소시킬 수 있는 오 경보 분류 모델을 제안한다. 제안된 오 경보 분류 모델은 데이터 마이닝 기법들 중에서 분류 기법을 기반으로 구현되었다. 실험 을 통해서 IDS에서 발생하는 경보 중에서 정상데이터이나 공격으로 잘못 판단하여 발생하는 False Positive의 발생율이 현저히 감소됨을 확인할 수 있었다. 제안된 오 경보 분류 모델은 경보메시지 축약의 효과가 있으며 침입탐지 시스템의 탐지율을 높이는데 활용될 수 있다.

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Detection of Methicillin-resistant Staphylococcs aureus from the Anterior Nares of Healthcare Workers in a Intensive Care Unit by Using PBP2a Rapid Kit and Direct Coagulase Test (중환자실에 근무하는 의료인의 전비강에서 PBP2a Rapid Kit와 직접 Coagulase 검사를 이용한 Methicillin-resistant Staphylococcus aureus의 검출)

  • Hong, Seung-Bok;Shin, Kyung-A;Son, Jae-Cheol;Shin, Seob-Kyeong
    • Korean Journal of Clinical Laboratory Science
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    • v.42 no.2
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    • pp.86-91
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    • 2010
  • We evaluated the performance of a novel screening test, PBP2a MRSA rapid kit (Dinona Inc., Iksan, Korea), for methicillin-resistant Staphylococcus aureus (MRSA) based on a immunochromatographic assay. The test is able to detect penicillin-binding protein 2a (PBP2a) using the nasal specimens from health care workers. The nasal specimens were obtained from 69 healthcare workers and were incubated in enrichment broth followed eight hours incubatin in BHI with cefoxitin $4{\mu}g/mL$. These broth were tested by PBP2a Rapid Kit. The enrichment broths were also directly tested for tube coagulase using the conventional identification method. 19 of 22 MRSA showed positive results by PBP2a rapid test and direct coagulase test (the sensitivity for detection of MRSA, 86.36%). While, 8 of 47 non-MRSA showed false positive results for the two tests. All of the 8 non-MRSA which showed false positive were co-colonizing isolates with MRCNS and MSSA. In addition, 46 of 49 methicillin-resistant staphylococci (MRS) showed positive results for PBP2a MRSA rapid kit (the sensitivity for detection of MRS, 93.8%), and all of 20 non-MRS showed negative results (specificity, 100%). The combination of PBP2a MRSA rapid kit and direct coagulase test showed the good sensitivity for detection of MRSA from anterior nares but frequently showed false positive results from the co-colonizing carrier with MRCNS and MSSA.

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AUC and VUS using truncated distributions (절단함수를 이용한 AUC와 VUS)

  • Hong, Chong Sun;Hong, Seong Hyuk
    • The Korean Journal of Applied Statistics
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    • v.32 no.4
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    • pp.593-605
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    • 2019
  • Significant literature exists on the area under the ROC curve (AUC) and the volume under the ROC surface (VUS) which are statistical measures of the discriminant power of classification models. Whereas the partial AUC is restricted on the false positive rate, the two-way partial AUC is restricted on both the false positive rate and true positive rate, which could be more efficient and accurate than partial AUC. The two-way partial AUC was suggested as more efficient and accurate than the partial AUC. Partial VUS as well as the three-way partial VUS were also developed for the ROC surface. A proposed AUC is expressed in this paper with probability and integration using two truncated distribution functions restricted on both the false positive rate and true positive rate. It is also found that this AUC has a relation with the two-way partial AUC. The three-way partial VUS for the ROC surface is also related to the VUS using truncated distribution functions. These AUC and VUS are represented and estimated in terms of Mann-Whitney statistics. Their parametric and non-parametric estimation methods are explored based on normal distributions and random samples.

False Alarm Minimization Technology using SVM in Intrusion Prevention System (SVM을 이용한 침입방지시스템 오경보 최소화 기법)

  • Kim Gill-Han;Lee Hyung-Woo
    • Journal of Internet Computing and Services
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    • v.7 no.3
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    • pp.119-132
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    • 2006
  • The network based security techniques well-known until now have week points to be passive in attacks and susceptible to roundabout attacks so that the misuse detection based intrusion prevention system which enables positive correspondence to the attacks of inline mode are used widely. But because the Misuse detection based Intrusion prevention system is proportional to the detection rules, it causes excessive false alarm and is linked to wrong correspondence which prevents the regular network flow and is insufficient to detect transformed attacks, This study suggests an Intrusion prevention system which uses Support Vector machines(hereinafter referred to as SVM) as one of rule based Intrusion prevention system and Anomaly System in order to supplement these problems, When this compared with existing intrusion prevention system, show performance result that improve about 20% and could through intrusion prevention system that propose false positive minimize and know that can detect effectively about new variant attack.

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(Automatic detection of pulmonary nodules in X-ray chest images) (흉부 X선 영상에서의 폐 노쥴 자동 탐지 기법)

  • Sung, Won;Kim, Eui-Jung;Park, Jong-Won
    • Journal of the Korea Computer Industry Society
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    • v.3 no.9
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    • pp.1279-1286
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    • 2002
  • Generally, radiologists can fail to detect pulmonary nodules in up to 30%. If an automatic system can inform the radiologists of thelocations of the doubtful nodules in the X-ray chest images, the frequency of mistakenly observed numbers of the nodules can be potentially reduced. This software is using morphological filtering and two feature-extraction techniques. The morphological filtering is the first process, which subsequently adds the operations of erosion and dilation to the original images so that this process can transform the original X-ray chest images into manageable ones. The false-positives are frequently being mistaken as nodules but actually these are not real nodules. The second process is the two feature-extraction techniques which are used to reduce the false-positives. Therefore, this system will make more effective detection of pulmonary nodules by reducing the false-positives when applied to the X-ray chest images which is difficult to get accurate detection.

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URL Normalization for Web Applications (웹 어플리케이션을 위한 URL 정규화)

  • Hong, Seok-Hoo;Kim, Sung-Jin;Lee, Sang-Ho
    • Journal of KIISE:Information Networking
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    • v.32 no.6
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    • pp.716-722
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    • 2005
  • In the m, syntactically different URLs could represent the same resource. The URL normalization is a process that transform a URL, syntactically different and represent the same resource, into canonical form. There are on-going efforts to define standard URL normalization. The standard URL normalization designed to minimize false negative while strictly avoiding false positive. This paper considers the four URL normalization issues beyond ones specified in the standard URL normalization. The idea behind our work is that in the URL normalization we want to minimize false negatives further while allowing false positives in a limited level. Two metrics are defined to analyze the effect of each step in the URL normalization. Over 170 million URLs that were collected in the real web pages, we did an experiment, and interesting statistical results are reported in this paper.

Improvement of Diagnostic Accuracy by Standardization in Diuretic Renal Scan (소아 이뇨 신장스캔에서 검사 표준화에 의한 폐쇄 진단 성능 향상)

  • Hyun, In-Young;Lee, Dong-Soo;Lee, Kyung-Han;Chung, June-Key;Lee, Myung-Chul;Koh, Chang-Soon;Kim, Kwang-Myung;Choi, Hwang;Choi, Yong
    • The Korean Journal of Nuclear Medicine
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    • v.29 no.4
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    • pp.497-503
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    • 1995
  • We evaluated diagnostic accuracy of diuretic renal scan with standardization in 45 childrens(107 hydronephrotic kidneys) with 91 diuretic assessments. Sensitivity was 100%, specificity was 78%, and accuracy was 84% in 49 hydronephrotic kidneys with standardization. Diuretic renal scan without standardization, sensitivity was 100%, specificity was 38%, and accuracy was 57 % in 58 hydronephrotic kidneys. The false-positive results were observed in 25 cases without standardization, and in 8 cases with standardization. In diuretic renal scans without standardization, the causes of false-positive results were 10 early injection of lasix before mixing of radioactivity in pelvocalyceal system, 4 full bladder, 2 markedly dilated pelvocalyceal systems postpyeloplsty, 6 extrarenal pelvis, and 3 immature kidneys of neonates. In diuretic renal scans with standardization the causes of false-positive results were 2 markedly dilated systems postpyeloplsty, 2 extrarenal pelvis, 1 immature kidney of neonate, and 2 severe venal dysfunction, 1 vesicoureteral reflux. In diuretic renal scan without standardization the false-positive results by inadequate study were common, but false-positive results by inadequate study were not found after standardization. The false-positive results by dilated pelvocalyceal systems postpyeloplsty, extrarenal pelvis, and immature kidneys of neonates were not dissolved after standardization. In conclusion, diagnostic accuracy of diuretic renal scan with standardization was useful in children with renal outflow tract obstruction by improving specificity significantly.

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A Study on the Validity of Passive Hemagglutination (PHA) Test for HBsAb (B형 간염 바이러스 표면 항체 검출을 위한 Passive Hemagglutination (PHA)방법의 정확도에 관한 연구)

  • Park, Byung-Joo
    • Journal of Preventive Medicine and Public Health
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    • v.20 no.1 s.21
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    • pp.114-119
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    • 1987
  • The author investigated the effect of some variables such as age, sex and the experience of past vaccination on the validity of PHA. The changing pattern of the validity with the change of PHA diagnostic criteria, and the relationship between PHA test result and RIA Ratio Unit were also studied. The results obtained were as follow; 1) No statistically significant difference was found in sensitivity, specificity and negative predictability by sex, but positive predictability was significantly higher in male than that in female. 2) Positive predictability was shown to become higher with the increase of age and nagative predictability was found to be significally different among age groups, but no statistically significant difference was found in sensitivity and specificity by age group. 3) Significantly low specificity and high positive predictability were found in past vaccined group, but no statistically significant difference was found in sensitivity and negative predictability between past vaccined group and non-vaccined group. 4) False negative cases by PHA were found to be the weak positive reactors by RIA and false positive rate of PHA was as high as 46.3 per cent. 5) Sensitivity and specificity of PHA at the diagnostic criteria of HBsAb titer 1:2 were 98.4% and 53.8% respectively, but after increasing the HBsAb titer to 1:64 as the diagnostic criteria the results were 60.0% and 95.6% respectively.

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Use of ultrasonography for improving reproductive efficiency in cows II. Comparative evaluation of ovarian structures using ultrasonography and plasma progesterone analysis in subestrous dairy cows (초음파 진단장치를 이용한 축우의 번식효율증진에 관한 연구 II. 무발정 젖소에서 초음파검사 및 progesterone 농도측정에 의한 난소 구조물의 비교평가)

  • Son, Chang-ho;Kang, Byong-kyu;Choi, Han-sun;Kang, Hyun-gu;Paik, In-seok;Suh, Guk-hyun
    • Korean Journal of Veterinary Research
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    • v.38 no.3
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    • pp.642-651
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    • 1998
  • The accuracy of ultrasonography for determining the presence of a functional corpus luteum in subestrous dairy cows was investigated, using a radioimmunoassay for progesterone in plasma. Luteal status (high or low progesterone concentrations) was diagnosed in 534 cows, using B-mode transrectal ultrasonography. Accuracy of ultrasonography was 96.3% and 88.8% in the cows with and without functional corpus luteum, respectively. In 362 cows diagnosed with functional corpus luteum by ultrasonographic examination, 20 cows were diagnosed with the non-functional corpus luteum by analysis of plasma progesterone concentrations (false positive). In 172 cows with non-functional corpus luteum by ultrasonographic examination, 13 cows were diagnosed with the functional corpus luteum based on plasma progesterone assay (false negative). Most of the corpus luteum with well-defined border and homogeneous echotexture were diagnosed with functional corpus luteum. All cows that were not detected a corpus luteum by ultrasonographic examination were diagnosed as non-functional corpus luteum. The corpus luteum of cows that were diagnosed with false positive appeared homogeneous echotexture and above 15 mm in diameter, but the corpus luteum was the non-functional corpus luteum within Day 5 (Day 0 is ovulation day) or after Day 19. The corpus luteum of cows that were diagnosed with false negative appeared heterogeneous echogenicity and below 15 mm in diameter, but the corpus luteum was the functional corpus luteum after Day 5 or around Day 17. It was concluded that accuracy of ultrasonography was excellent for determining the presence of a functional corpus luteum in subestrous dairy cows. The corpus luteum that was diagnosed with false positive or false negative was the developing or regressing states. Thus, ultrasonography was required a serial examination of two or three times accurately diagnosing these corpus luteum.

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