• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.6
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• pp.1070-1075
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• 2006

TETRA system provides the radio authentication service which permits only authorized radio to access network. Radio authentication is the process which checks the sameness of authentication-key(K) shared between radio and authentication center by challenge-response protocol. TETRA standard authentication protocol can prevent the clone radio to copy ISSI from accessing network, but can't prevent the clone radio to copy ISSI & authentication-key. This paper analyzes authentication-key generation/delivery/infection model in TETRA authentication system and analyzes the threat of clone radio caused by authentication-key exposure. Finally we propose the new authentication protocol which prevent the clone radio to copy ISSI & authentication-key from accessing network.

• 대한생식의학회:학술대회논문집
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• 1994.10a
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• pp.36.2-37
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• 1994

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.187-190
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• 2006

TETRA system provides the radio authentication service which permits only authorized radio to access network. Radio authentication is the process which checks the sameness of authentication-key(K) by challenge-response protocol between radio and authentication center. This paper analyzes authentication-key generation/delivery/injection model in TETRA authentication system and analyzes the threat of clone radio caused by authentication-key exposure.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.3
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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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• v.25 no.5
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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.