• 제목/요약/키워드: False-negative results

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지하공동구의 CCTV 영상 기반 AI 연기 감지 모델 개발 (Development of AI Detection Model based on CCTV Image for Underground Utility Tunnel)

  • 김정수;박상미;홍창희;박승화;이재욱
    • 한국재난정보학회 논문집
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    • 제18권2호
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    • pp.364-373
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    • 2022
  • 연구목적: 본 논문은 지하공동구의 초기 화재 감지를 위해 CCTV를 활용한 AI 연기 객체 감지 모델을 개발하는데 목적이 있다. 연구방법:비정형성이 높은 연기 객체의 감지 성능을 제고하기 위해 화재 감지에 특화된 딥러닝 객체 감지 모델을 지하공동구 연기 감지에 특화되도록 학습시켰고, 학습데이터셋의 정제 및 학습 중 Gradient explosion 완화 등 감지 성능 개선을 위한 방법들을 적용해 모델 결과를 비교하였다. 연구결과: 결과는 제안된 방법을 통해 모델 성능을 향상시켰고 mAP 등의 지표를 평가를 통해 개발 모델이 우수한 성능을 보유하고 있음을 보여준다. 최종 모델은 지하공동구 환경의 연기에 대해 미탐이 낮은 반면 오탐이 다수 발견되는 성능을 보였다. 결론: 본 논문의 모델은 지하공동구 관리시스템과 연계를 통해 보완함으로써 지하공동구의 연기 객체 감지에 활용할 수 있을 것으로 판단된다.

갑상선 결절의 진단에 있어서 고해상능 초음파검사의 가치 (The Value of High Resolution Ultrasonography in Diagnosis of Thyroid Nodule)

  • 심형진;정희문;윤정한;제갈영종;박진균
    • 대한두경부종양학회지
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    • 제6권2호
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    • pp.114-118
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    • 1990
  • A clinical study of 37 cases with thyroid nodules, which were treated by surgical excision and confirmed pathologically at the Department of Surgery, Chonnam National University Medical School, from Dec. 1988 to Feb. 1990, was conducted and following results were obtained in ultrasonographic evaluation of thyroid nodules. 1) The thyroid adenoma were showed well-defined margin, homogenous internal echo and surrounding Halo, but thyroid cancer were showed ill-defined margin, inhomogenous internal echo and no surrounding Halo. 2) The sensitivity of high resoution ultrasonography compared with pathologic diagnosis to thyroid cancer was 87.5%, specificity 94.1%, accuracy 88%, false positive 5.88%, and negative 12.5%.

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기능성 근적외선 분광기를 이용한 전전두엽 영역에서의 사건 기반 뇌활성 특이 신호의 추출 (Functional Near-Infrared Spectroscopy Extracts EROS in the Prefrontal Cortex)

  • 강호열;방성근;송성호;이은주
    • 전기학회논문지
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    • 제58권1호
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    • pp.210-215
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    • 2009
  • In this study event-related optical signals were extracted from the prefrontal cortexes using functional near infrared spectroscopy while subjects were carrying out 2-back working memory tasks. Four events such as start, yes, no, and error were considered based on the onsets of the stimulus, positive true responses, positive false responses, and negative responses in the 2-back working memory task, respectively. The optical signals recorded were analyzed by peri-event histograms and power spectrum distributions. The results showed specific characteristics of the event-related optical neuronal signals and an opened possibility of an application to control a non-invasive brain-computer interface system or an object of a virtual reality.

Endoscopic features aiding the diagnosis of gastric mucosa-associated lymphoid tissue lymphoma

  • Park, Byung Sam;Lee, Si Hyung
    • Journal of Yeungnam Medical Science
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    • 제36권2호
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    • pp.85-91
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    • 2019
  • The incidence of gastric mucosa-associated lymphoid tissue (MALT) lymphoma is increasing worldwide, but the diagnosis is difficult. Most patients are asymptomatic or complain of nonspecific gastrointestinal symptoms. As the endoscopic features of gastric MALT lymphoma are variable and nonspecific, the possibility of this condition may be overlooked during esophagogastroduodenoscopy, and it remain undiagnosed. Therefore, this condition needs to be considered when an abnormal mucosa is observed during this procedure. Biopsy performed during endoscopy is the primary diagnostic test, but false negative results are possible; large numbers of samples should be collected from both normal and abnormal mucosae. Endoscopic ultrasonography is useful to assess the depth of invasion and to predict the treatment response. After treatment, follow-up tests are required every 3 months until complete remission is achieved, and annually thereafter. Early diagnosis of gastric MALT lymphoma is difficult, and its diagnosis and follow-up require wide experience and competent endoscopic technique.

An improvement of real-time polymerase chain reaction system based on probe modification is required for accurate detection of African swine fever virus in clinical samples in Vietnam

  • Tran, Ha Thi Thanh;Dang, Anh Kieu;Ly, Duc Viet;Vu, Hao Thi;Hoang, Tuan Van;Nguyen, Chinh Thi;Chu, Nhu Thi;Nguyen, Vinh The;Nguyen, Huyen Thi;Truong, Anh Duc;Pham, Ngoc Thi;Dang, Hoang Vu
    • Asian-Australasian Journal of Animal Sciences
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    • 제33권10호
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    • pp.1683-1690
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    • 2020
  • Objective: The rapid and reliable detection of the African swine fever virus (ASFV) plays an important role in emergency control and preventive measures of ASF. Some methods have been recommended by FAO/OIE to detect ASFV in clinical samples, including realtime polymerase chain reaction (PCR). However, mismatches in primer and probe binding regions may cause a false-negative result. Here, a slight modification in probe sequence has been conducted to improve the qualification of real-time PCR based on World Organization for Animal Health (OIE) protocol for accurate detection of ASFV in field samples in Vietnam. Methods: Seven positive confirmed samples (four samples have no mismatch, and three samples contained one mutation in probe binding sites) were used to establish novel real-time PCR with slightly modified probe (Y = C or T) in comparison with original probe recommended by OIE. Results: Both real-time PCRs using the OIE-recommended probe and novel modified probe can detect ASFV in clinical samples without mismatch in probe binding site. A high correlation of cycle quantification (Cq) values was observed in which Cq values obtained from both probes arranged from 22 to 25, suggesting that modified probe sequence does not impede the qualification of real-time PCR to detect ASFV in clinical samples. However, the samples with one mutation in probe binding sites were ASFV negative with OIE recommended probe but positive with our modified probe (Cq value ranked between 33.12-35.78). Conclusion: We demonstrated for the first time that a mismatch in probe binding regions caused a false negative result by OIE recommended real-time PCR, and a slightly modified probe is required to enhance the sensitivity and obtain an ASF accurate diagnosis in field samples in Vietnam.

모형 구성 과정에서 나타나는 초등학생의 인지, 감정적 반박 -인식적 감정을 중심으로- (Elementary Students' Cognitive-Emotional Rebuttals in Their Modeling Activity: Focusing on Epistemic Affect)

  • 한문현;김희백
    • 한국과학교육학회지
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    • 제37권1호
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    • pp.155-168
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    • 2017
  • 본 연구는 초등학생들이 모형 구성 과정에서 어떻게 인지, 감정적 반박을 사용했는지, 특히 그들의 감정과 인지적 과정이 어떻게 상호 작용하여 반박이 나타나게 되었는지 탐색한 것이다. 초등학교 5학년, 25명이 과학 수업의 일환으로 연구에 참여하였다. 6차시 동안 학생들은 지속적인 논의를 통해 인간 호흡 운동 시스템 모형을 구성하였다. 연구 결과에 따르면 초등학생들은 모형 구성 과정에서 정교화형 반박, 방어형 반박, 비난형 반박을 사용하였다. 인지적 비형형 상태와 연관된 부정적 인식적 감정과 인지적 과정의 상호작용을 통해 나타난 정교화형 반박은 소집단 모형을 정교화하는데 도움을 주었다. 반면 관계 악화와 관련된 부정적 인식적 감정과 인지적 과정의 상호작용을 통해 나타난 방어형 반박과 비난형 반박은 모형의 정교화를 이끌기보다는 다른 학생들의 제안, 설명을 배제하거나 공격하기 위해 사용되었고, 이 때의 부정적 인식적 감정은 다른 학생들의 바람직하지 않은 행동에 의해 생성되었다. 연구 결과는 학생들의 반박이 인식적 감정과 관련된 인식론적 역동에 의해 나타나게 됨을 보여준다. 본 연구는 학생들의 초보적, 수정될 필요가 있는 설명으로부터 부정적 인식적 감정이 생성되는 것은 모형 구성 과정에서 모형 발달을 돕는 정교화형 반박이 나타나게 되는 측면에서는 자연스러운 것이며, 정교화형 반박을 수용하도록 돕는 학생들의 감정 조절은 모형을 발달시키는데 도움이 될 수 있음을 논의한다. 또한 관계의 악화로 인해 나타날 수 있는 부정적 인식적 감정은 초등학생이 조절하기 어려우며, 이것이 협력적 모형 구성을 어렵게 할 수 있음을 제언한다.

Robust Reference Intervals for Serum Kappa and Lambda Free Light Chains from a Multi Centre Study Population from Hyderabad, India: Myeloma Diagnostic Implications

  • Mohammed, Noorjahan;Chandran, Priscilla Abraham;Kandregula, Madhavi;Mattaparthi, Ratna Deepika;Gundeti, Sadasivudu;Volturi, Jyotsna;Darapuneni, Radhika;Raju, Sree Bhushan;Dattatreya, Palanki Satya
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권5호
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    • pp.2605-2610
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    • 2016
  • The International Myeloma Working Group considers the serum free light chain (SFLC) assay to be an adjunct to traditional tests. Apart from the FLC ratio, the absolute values of individual free light chains also are gaining importance as they appear to be more relevant in certain clinical settings. Automated assays are available for their determination. As laboratories put new test systems into use catering to different disease populations, they are required by accreditation and certification bodies to verify or establish performance specifications, including reference intervals (RIs) representative of their population. Our aim was to establish local RIs for SFLC in a multicentre representative healthy population using a robust method. There was no significant relationship between SFLC levels and age, gender and creatinine levels. The 95% RI for ${\kappa}SFLC$ was 4.81 to 33.86mg/L, for ${\lambda}$ SFLC was 5.19 to 23.67mg/L and for ${\kappa}/{\lambda}SFLC$ was 0.36 to 2.33, significantly higher than the values given by the manufacturer. The ${\kappa}/{\lambda}$ SFLC ratio at 2.23, covering 100% of the data, showed 72% sensitivity (95% CI=39.0 - 94.0), 100% specificity (95% CI=71.5 - 100.0), 100% PPV (95% CI=21.5 - 100.0), 95% NPV (95% CI=75.4 - 99.9), and 79% accuracy (95% CI=56.0 - 93.0). In the patient group, kit RI for ${\kappa}/{\lambda}$ SFLC ratio classified 45.5% (n=5) as positive vs 9.1% (n=1) positive by the study RI, while the kit RI for kappa FLC classified 90.9% (n=10) as positive vs 54.5% (n=6), indicating increased probability of false positive test results with the kit RI when applied to our patient population. Appropriate and specific reference intervals and criteria values result in fewer false-positive and false-negative results which means fewer wrong or missed diagnoses.

Ultrasonographic Features of Triple-Negative Breast Cancer: a Comparison with Other Breast Cancer Subtypes

  • Yang, Qi;Liu, Hong-Yan;Liu, Dan;Song, Yan-Qiu
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권8호
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    • pp.3229-3232
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    • 2015
  • Background: Triple-negative breast cancer (TNBC) is known to be associated with aggressive biologic features and a poor clinical outcome. Therefore, early detection of TNBC without missed diagnosis is a requirement to improve prognosis. Preoperative ultrasound features of TNBC may potentially assist in early diagnosis as characteristics of disease. Purpose: To retrospectively evaluate the sonographic features of TNBC compared to ER (+) cancers which include HER(-) and HER2 (+), and HER2 (+) cancers which are ER (-). Materials and Methods: From June 2012 through June 2014, sonographic features of 321 surgically confirmed ER (+) cancers (n=214), HER2 (+) cancers (n=66), and TNBC (n=41) were retrospectively reviewed by two ultrasound specialists in consensus. The preoperative ultrasound and clinicopathological features were compared between the three subtypes. In addition, all cases were analyzed using morphologic criteria of the ACR BI-RADS lexicon. Results: Ultrasonographically, TNBC presented as microlobulated nodules without microcalcification (p=0.034). A lower incidence of ductal carcinoma in situ (p<0.001), invasive tumor size that is>2 cm (p=0.011) and BI-RADS category 4 (p<0.001) were significantly associated with TNBC. With regard to morphologic features of 41 TNBC cases, ultrasonographically were most likely to be masses with irregular (70.7%) microlobulated shape (48.8%), be circumscribed (17.1%) or have indistinct margins (17.1%) and parallel orientation (68.9%). Especially TNBC microlobulated mass margins were more more frequent than with ER (+) (2.0%) and HER2 (+) (4.8%) cancers. Conclusions: TNBC have specific characteristic in sonograms. Ultrasonography may be useful to avoid missed diagnosis and false-negative cases of TNBC.

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
    • 한국축산식품학회지
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    • 제34권5호
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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.

Development of a Novel Immunochromatographic Assay for Rapid Detection of OXA-23 β-lactamase-producing Acinetobacter baumannii

  • Ji, Gil Young;Song, Hyung Geun;Jo, Mi Young;Hong, Seung Bok;Shin, Kyeong Seob
    • 대한의생명과학회지
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    • 제22권2호
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    • pp.29-36
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    • 2016
  • Among the several agents causing carbapenem resistance of Acinetobacter baumannii, the most common cause is OXA-23 ${\beta}$-lactamase, which is known to hydrolyze carbapenem. To effectively control dissemination of carbapenem-resistant Acinetobacter baumannii (CRAB), development of both rapid and easy-to-use detection methods are required. The aim of this study is to develop a novel immunochromatographic assay (ICA) for rapid detection of OXA-23 ${\beta}$-lactamase. Of the seven monoclonal antibodies (mAbs) screened by ELISA, four mAbs (4G6, 4H6, 6G4, 9A4) exhibited high reactivity. Of these four specific antibodies, the combination of 6G4/4G6 showed the greatest reactivity and this combination of mAbs (6G4/4G6 mAbs) was used to develop the OXA-23 ${\beta}$-lactamase ICA. Of 102 A. baumannii isolates tested, the OXA-23 ${\beta}$-lactamase ICA results were consistent with PCR analysis except one false positive and one false negative isolate. The overall sensitivity and specificity were 98.36% and 97.56%, respectively. In conclusion, to the best of our knowledge, we have developed the first specific antibody set to detect OXA-23 ${\beta}$-lactamase using an ICA kit. This novel ICA can be used as a reliable and easy-to-use immunological assay for detection of OXA-23 ${\beta}$-lactamase producing CRAB in clinical laboratories.