• Pediatric Infection and Vaccine
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• v.10 no.2
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• pp.153-158
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• 2003

Purpose : The incidence of hepatitis B virus infection has gradually decreased since 1983 when hepatitis B vaccine was firstly produced. This study was performed to evaluate the efficacy of hepatitis B immunization. Methods : The elementary, middle and high school children in Incheon area were enrolled in this study in 1997 and 1998. Hepatitis B virus surface antigen(HBsAg) was measured using reversed passive hemagglutination(RPHA). Results : The results were as follows The positive rates of HBsAg in elementary, middle and high school children were 0.7%(337/46,861), 2.5%(381/15,026) and 3.1%(681/21,938) respectively in 1997 and 0.6%(257/41,946), 2.7%(379/13,652) and 2.4%(628/25,277) respectively in 1998. The positive rates of HBsAg in children under 19 years of age in 1985, 1990 and 1995 were 6.1, 5.2 and 3.5% respectively. Conclusion : The positive rates of HBsAg in elementary school children in 1997 and 1998 has decreased compared with those of the previous studies. The majority of elementary school children were given hepatitis B vaccination. These results suggest that hepatitis B vaccines used in Korea were effective for prevention of hepatitis B infection in school children.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.635-641
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• 2016

Because of prohibitive data storage requirements in large-scale simulations, the memory problem is an obstacle for Monte Carlo (MC) codes in accomplishing pin-wise three-dimensional (3D) full-core calculations, particularly for whole-core depletion analyses. Various kinds of data are evaluated and quantificational total memory requirements are analyzed based on the Reactor Monte Carlo (RMC) code, showing that tally data, material data, and isotope densities in depletion are three major parts of memory storage. The domain decomposition method is investigated as a means of saving memory, by dividing spatial geometry into domains that are simulated separately by parallel processors. For the validity of particle tracking during transport simulations, particles need to be communicated between domains. In consideration of efficiency, an asynchronous particle communication algorithm is designed and implemented. Furthermore, we couple the domain decomposition method with MC burnup process, under a strategy of utilizing consistent domain partition in both transport and depletion modules. A numerical test of 3D full-core burnup calculations is carried out, indicating that the RMC code, with the domain decomposition method, is capable of pin-wise full-core burnup calculations with millions of depletion regions.