• 한국정보통신학회논문지
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• 제10권6호
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• pp.1070-1075
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• 2006

TETRA 시스템에서는 Challenge-response 프로토콜에 의해 단말기와 인증 센터간에 사전에 공유된 인증키가 일치하는지를 확인하는 인증 서비스를 제공함으로써 인가된 단말기만 망에 접속하도록 하고 있다. 그러나 TETRA 표준 인증 프로토콜은 단말기 식별자인 ISSI(Individual Short Subscriber Identity)가 복제된 단말기의 망 접속은 차단할 수 있지만, ISSI와 인증키가 모두 복제된 경우 복제단말기의 불법 사용을 막을 수 없는 취약점이 존재한다. 본 논문에서는 TETRA 표준인 ETSI규격에서 정의하고 있는 인증 프로토콜을 간략히 설명하고 인증 과정에서 사용되는 인증키의 생성/분배/주입 모델을 설명 한 후, 인증키가 인증 센터로 전달되는 과정에서 노출되었을 경우 발생할 수 있는 복제단말기의 위협을 분석한다. 마지막으로 ISSI와 인증키가 복제된 단말기의 망 접속을 차단할 수 있는 새로운 인증 프로토콜을 제안한다.

• 대한생식의학회:학술대회논문집
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• 대한불임학회 1994년도 추계 학술대회 및 정기총회
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• pp.36.2-37
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• 1994

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.187-190
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• 2006

TETRA 시스템에서는 인가된 단말기만이 망에 접속하도록 하기 위해 단말기 인증 서비스를 제공한다. 단말기 인증이란 Challenge-response 프로토콜에 의해 단말기와 인증센터에 사전에 공유된 인증키가 일치하는지를 확인하는 과정이다. 본 논문에서는 TETRA 인증 시스템에서 인증키 생성/분배/주입 모델을 분석하고, 인증키의 노출로 인한 복제단말기의 위협을 분석한다.

• 대한기계학회논문집B
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• 제28권3호
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• pp.271-280
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• 2004

Assessment of image registration for Pressure Sensitive Paint (PSP) was performed. A 16 bit camera and LED lamp were used with Uni-FIB paint (ISSI). Because of model displacement and deformation at 'wind-on' condition, a large error of the intensity ratio was induced between 'wind-on' and' wind-off images. To correct the error, many kinds of image registrations were tested. At first, control points were marked on the model surface to find the coefficients of polynomial transform functions between the 'wind-off' 'wind-on' images. The 2nd-order polynomial function was sufficient for representing the model displacement and deformation. An automatic detection scheme was introduced to find the exact coordinates of the control points. The present automatic detection algorithm showed more accurate and user-friendly than the manual detection algorithm. Since the coordinates of transformed pixel were not integer, five interpolation methods were applied to get the exact pixel intensity after transforming the 'wind-on' image. Among these methods, the cubic convolution interpolation scheme gave the best result.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제25권5호
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• pp.422-431
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• 2022

Purpose: At the beginning of the Coronavirus disease (COVID-19) epidemic, physicians paid close attention to children with chronic diseases to prevent transmission or a severe course of infection. We aimed to measure the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody levels in children with chronic gastrointestinal and liver diseases to analyze the risk factors for infection and its interaction with their primary disease. Methods: This cross-sectional study analyzed SARS-CoV-2 antibody levels in patients with gastrointestinal and liver diseases (n=141) and in healthy children (n=48) between January and February 2021. Results: During the pandemic, 10 patients (7%) and 1 child (2%) had confirmed COVID-19 infection (p=0.2). The SARS-CoV-2 antibody test was positive in 36 patients (25.5%) and 11 children (22.9%) (p=0.7). SARS-CoV-2 antibody positivity was found in 20.4%, 26.6%, 33.3%, and 33.3% of patients with chronic liver diseases, chronic gastrointestinal tract diseases, cystic fibrosis, and liver transplantation recipients, respectively (p>0.05, patients vs. healthy children). Risk factors for SARS-CoV-2 antibody positivity were COVID-19-related symptoms (47.2% vs. 14.2%, p=0.00004) and close contact with SARS-CoV-2 polymerase chain reaction-positive patients (69.4% vs. 9%, p<0.00001). The use, number, and type of immunosuppressants and primary diagnosis were not associated with SARS-CoV-2 antibody positivity. The frequency of disease activation/flare was not significant in patients with (8.3%) or without (14.2%) antibody positivity (p=0.35). Conclusion: SARS-CoV-2 antibodies in children with chronic gastrointestinal and liver diseases are similar to that in healthy children. Close follow-up is important to understand the long-term effects of past COVID-19 infection in these children.