• 한국컴퓨터정보학회논문지
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• 제28권11호
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• pp.89-101
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• 2023

사이버 공격으로 인한 국가, 기업 등의 피해를 막기 위해 공격자의 접근을 사전에 감지하는 이상 탐지 기술이 꾸준히 연구되어왔다. 외부 혹은 내부에서 침입하는 공격들을 즉각적으로 막기 위해 실행시간의 감축과 오탐지 감소는 필수불가결하다. 본 연구에서는 공격 이벤트의 유형과 빈도가 이상 탐지 정탐률 향상 및 오탐률 감소에 영향을 미칠 것으로 가설을 세우고, 검증을 위해 Los Alamos National Laboratory의 2015년 로그인 로그 데이터셋을 사용하였다. 전처리 된 데이터를 대표적인 이상행위 탐지 알고리즘에 적용한 결과, 공격 이벤트 유형과 빈도를 동시에 적용한 특성을 사용하는 것이 이상행위 탐지의 오탐률과 수행시간을 절감하는데 매우 효과적임을 확인하였다.

• 대한임베디드공학회논문지
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• 제19권1호
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• pp.1-8
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• 2024

Robotic arms have been widely utilized in various labor-intensive industries such as manufacturing, agriculture, and food services, contributing to increasing productivity. In the development of industrial robotic arms, camera sensors have many advantages due to their cost-effectiveness and small sizes. However, estimating object positions is a challenging problem, and it critically affects to the robustness of object manipulation functions. This paper proposes a method for estimating the 3D positions of objects, and it is applied to a pick-and-place task. A deep learning model is utilized to detect 2D bounding boxes in the image plane, and the pinhole camera model is employed to compute the object positions. To improve the robustness of measuring the 3D positions of objects, we analyze the effect of lens distortion and introduce a false positive filtering process. Experiments were conducted on a real-world scenario for moving medicine bottles by using a camera-based manipulator. Experimental results demonstrated that the distortion removal and false positive filtering are effective to improve the position estimation precision and the manipulation success rate.

• 대한임상검사과학회지
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• 제45권4호
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• pp.149-153
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• 2013

Candidiasis is a fungal infection of the most common causes; generally, opportunistic infections occur often in patients with weakened immune systems. Because of high rates in fungal infection patients and increasing frequency of being isolated from clinical materials, quickly identifying of Candida albicans is critical. By identifying 404 yeast cell strains of referred samples via API 20C kits, NGL and PRO tests and Germ tube (GT) test were conducted and compared. In the 3.0 McFarland yeast cells, 0.1% ${\rho}-nitrophenyl-N-acetyl-{\beta}-D-galactosaminide$ (NGL) and 0.04% ${\small{L}}$-proline ${\beta}$-naphtylamide (PRO) were each put in test tubes and incubated at $35^{\circ}C$ for 15, 30, 60 and 90 minutes. Afterwards, 1 drop of 2% NaOH was applied, and if the color turned yellow; it was positive for NGL test. Afterwards, 1% ${\rho}$-dimethylaminocinnamaldehyde was applied, and if the upper layer turned pink or red, it was positive for PRO test. NGL and PRO tests were conducted for all C. albicans and identified accurately within 30 minutes. In NGL, PRO test, false-positive, negative were not seen, whereas, GT test showed false-positive in 1 strain and false-negative in 3 strains. Therefore, sensitivity and specificity of NGL, PRO tests were 100% and 99.5%, respectively, and positive and negative predictive rate were 99.5% and 100%, respectively. However, GT test sensitivity and specificity were 98.5% and 99.5%, respectively, and positive and negative predictive rates were 99.5% and 98.5%, respectively. In conclusion, NGL, PRO tests are better than GT tests for sensitivity and specificity, therefore, these reliable tests will be useful in clinical laboratories.

• Journal of Radiation Protection and Research
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• 제44권2호
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• pp.64-71
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• 2019

Background: It is very difficult to distinguish between a radioactive contamination source and background radiation from natural radionuclides in the marine environment by means of online monitoring system. The objective of this study was to investigate a statistical process for triggering abnormal level of count rate data measured from our on-line seawater radioactivity monitoring. Materials and Methods: Count rate data sets in time series were collected from 9 monitoring posts. All of the count rate data were measured every 15 minutes from the region of interest (ROI) for $^{137}Cs$ ($E_{\gamma}=661.6keV$) on the gamma-ray energy spectrum. The Shewhart ($3{\sigma}$), CUSUM, and Bayesian S-R control chart methods were evaluated and the comparative analysis of determination methods for count rate data was carried out in terms of the false positive incidence rate. All statistical algorithms were developed using R Programming by the authors. Results and Discussion: The $3{\sigma}$, CUSUM, and S-R analyses resulted in the average false positive incidence rate of $0.164{\pm}0.047%$, $0.064{\pm}0.0367%$, and $0.030{\pm}0.018%$, respectively. The S-R method has a lower value than that of the $3{\sigma}$ and CUSUM method, because the Bayesian S-R method use the information to evaluate a posterior distribution, even though the CUSUM control chart accumulate information from recent data points. As the result of comparison between net count rate and gross count rate measured in time series all the year at a monitoring post using the $3{\sigma}$ control charts, the two methods resulted in the false positive incidence rate of 0.142% and 0.219%, respectively. Conclusion: Bayesian S-R and CUSUM control charts are better suited for on-line seawater radioactivity monitoring with an count rate data in time series than $3{\sigma}$ control chart. However, it requires a continuous increasing trend to differentiate between a false positive and actual radioactive contamination. For the determination of count rate, the net count method is better than the gross count method because of relatively a small variation in the data points.

• Asian Pacific Journal of Cancer Prevention
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• 제16권16호
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• pp.7381-7384
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• 2015

This study was conducted to 1206 women who had cervical cancer screening at Chonburi Cancer Hospital. The spilt-sample study aimed to compare the efficacy of abnormal cervical cells detection between liquid-based cytology (LBC) and conventional cytology (CC). The collection of cervical cells was performed by broom and directly smeared on a glass slide for CC then the rest of specimen was prepared for LBC. All slides were evaluated and classified by The Bethesda System. The results of the two cytological tests were compared to the gold standard. The LBC smear significantly decreased inflammatory cell and thick smear on slides. These two techniques were not difference in detection rate of abnormal cytology and had high cytological diagnostic agreement of 95.7%. The histologic diagnosis of cervical tissue was used as the gold standard in 103 cases. Sensitivity, specificity, positive predictive value, negative predictive value, false positive, false negative and accuracy of LBC at ASC-US cut off were 81.4, 75.0, 70.0, 84.9, 25.0, 18.6 and 77.7%, respectively. CC had higher false positive and false negative than LBC. LBC had shown higher sensitivity, specificity, PPV, NPV and accuracy than CC but no statistical significance. In conclusion, LBC method can improve specimen quality, more sensitive, specific and accurate at ASC-US cut off and as effective as CC in detecting cervical epithelial cell abnormalities.

• Journal of Gastric Cancer
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• 제6권4호
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• pp.291-294
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• 2006

F-18 FDG-PET/CT는 위암의 재발여부를 평가하는데 있어서 이용될 수 있으나 위양성을 일으키는 경우가 종종 보고된다. 저자들은 위암으로 위절제술과 Mitomycin C를 이용한 복강 내 화학요법 시행 후 F-18 FDG-PET/CT상 위양성의 복강 내 활성화 탄소 육아종을 경험하였다. 46세 남자환자는 수술 후 6개월째 시행한 CT상 우측 대장 뒤에서 종물이 발견되었으나 크기 변화 없다가 36개월째 크기의 증가를 보여 시행한 F-18 FDG-PET/CT상 전이 종양이 의심되었다. 진단적 개복술을 시행하여 제거한 종양은 조직학적 검사상 활성화 탄소 육아종으로 진단되었다. 이처럼 복강 내 화학요법을 시행한 환자의 F-18 FDG-PET/CT의 해석에 있어서 활성화 탄소 육아종에 의한 위양성 소견의 가능성을 염두에 두어야 할 것이다.

• 대한건축학회논문집:구조계
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• 제36권3호
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• pp.113-120
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• 2020

The purpose of this study is to compare the models of Deep Learning-based Convolution Neural Network(CNN) for concrete crack detection. The comparison models are AlexNet, GoogLeNet, VGG16, VGG19, ResNet-18, ResNet-50, ResNet-101, and SqueezeNet which won ImageNet Large Scale Visual Recognition Challenge(ILSVRC). To train, validate and test these models, we constructed 3000 training data and 12000 validation data with 256×256 pixel resolution consisting of cracked and non-cracked images, and constructed 5 test data with 4160×3120 pixel resolution consisting of concrete images with crack. In order to increase the efficiency of the training, transfer learning was performed by taking the weight from the pre-trained network supported by MATLAB. From the trained network, the validation data is classified into crack image and non-crack image, yielding True Positive (TP), True Negative (TN), False Positive (FP), False Negative (FN), and 6 performance indicators, False Negative Rate (FNR), False Positive Rate (FPR), Error Rate, Recall, Precision, Accuracy were calculated. The test image was scanned twice with a sliding window of 256×256 pixel resolution to classify the cracks, resulting in a crack map. From the comparison of the performance indicators and the crack map, it was concluded that VGG16 and VGG19 were the most suitable for detecting concrete cracks.

• 분석과학
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• 제35권6호
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• pp.242-248
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• 2022

Luminol 혹은 Bluestar가 혈액 및 표백제와 반응할 때 ethylenediamine (EDA)이 미치는 영향에 대해 연구하였다. 이를 위해 거름종이에 혈액, 염소계 표백제, 산소계 표백제를 묻힌 후 EDA를 첨가한 luminol 혹은 Bluestar로 처리한 후 화학발광의 세기 변화를 관찰하였다. 그 결과 EDA의 농도를 증가시켜도 luminol (혹은 Bluestar)-혈액 반응의 화학발광 세기는 변하지 않는다는 것을 알 수 있었다. 그러나 EDA의 농도가 증가할수록 luminol (혹은 Bluestar)-염소계 표백제 반응의 화학발광 세기는 감소하였고, luminol (혹은 Bluestar)-산소계 표백제 반응의 화학발광 세기는 증가하는 현상이 관찰되었다. 이를 통해 luminol (혹은 Bluestar)로 혈액 검출 시약을 제조할 때 EDA를 첨가할 경우, EDA는 염소계 표백제에 의해 유발되는 위양성 반응을 억제하고 산소계 표백제의 위양성 반응을 유발한다는 것을 알 수 있었다. 이런 점을 종합해서 판단할때 luminol이나 Bluestar로 혈액을증강할 때 EDA를 첨가하는것은 적절하지 않다.

• 한국정보전자통신기술학회논문지
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• 제15권2호
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• pp.117-123
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• 2022

현재 코로나19 확진자는 전 세계적으로 빠르게 증가하고 있다. 감염 확산을 억제할 수 있는 방법으로 신속한 코로나19 검사를 통한 확진자를 찾아내는 것이다. 본 논문에서는 코로나19 진단을 위한 잡음 그룹검사(Noisy Group Testing) 문제를 살펴본다. 기존에 제안한 그룹검사 문제는 측정잡음을 무시하였지만, 최근 들어 코로나19 검사시에 위 양성(false positive)과 위음성(false negative) 사례가 발생하고 있다. 이에 대해 본 논문에서는 잡음 그룹검사 문제를 정의하고 측정잡음이 성능에 얼마나 영향을 미치는지 분석한다. 본 연구를 통해 우리는 코로나19 검사 양성률이 낮은 그룹검사를 수행할수록 측정잡음(measurement noise)에 덜 민감하도록 그룹검사 시스템이 설계되어야 함을 제시한다. 또한 최근 발표한 다른 복원 알고리즘들과 비교하여 본 연구에서 제안하는 신호 복원 알고리즘이 잡음 그룹검사에서 좋은 성능을 보여준다.

• Korean Journal of Radiology
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• 제21권4호
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• pp.442-449
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• 2020

Objective: To compare the diagnostic performance of contrast-enhanced spectral mammography (CESM) versus ultrasonography (US) in symptomatic patients with dense breasts, while using histology as the gold standard. Materials and Methods: After obtaining approval from the local ethics board, this prospective study collected data from patients with symptomatic breasts who underwent CESM and US examinations from May 1, 2017 to September 30, 2017. We then selected those with dense breasts and pathological results as our sample population. Both CESM and US results were classified by a radiologist through the Breast Imaging Reporting and Data System, and the results were compared with their corresponding histological results. The chi-square test was conducted to compare the diagnostic performance of CESM and US, and the receiver operating characteristic curves for the two imaging modalities were obtained. Results: A total of 131 lesions from 115 patients with dense breasts were included in this study. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 93.8%, 88.1%, 88.2%, 93.7%, and 90.8% for CESM, and 90.6%, 82.1%, 82.9%, 90.2%, and 86.3% for US, respectively. The p values for sensitivity, specificity, PPV, NPV, and accuracy were 0.687, 0.388, 0.370, 0.702, and 0.238, respectively. The area under the curve of CESM (0.917) was comparable with that of US (0.884); however, the differences between CESM and US were not statistically significant (p = 0.225). Eight false-positive cases and 4 false-negative cases for breast cancer were found in CESM, while 12 false-positive cases and 6 false-negative cases were found in US. Conclusion: The diagnostic performances of CESM and US are comparable in symptomatic women with dense breasts; however, the routine use of additional US imaging is questionable for lesions that can be detected by CESM.