• Journal of Radiation Protection and Research
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• v.18 no.1
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• pp.37-51
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• 1993

A standard radon chamber and a radon generator adjusted by ventilation system which had used in this research were assumed to calculate theoretically the concentration of radon progeny using Jacobi model theory. On the one hand, the filter sampled from the radon standard chamber and the radon generator was measured and analysed by the alpha spectrometry method. It is clear that measured result shows a good agreement with theoretical result. Therefore, it is observed that this research can made a great contribution to more accurate internal dose assessment by alpha emission of radon progeny in indoor radon environment, and fast individual measurement and determination of concentration for radon progeny.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.529-530
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• 2003

우라늄(U-238)의 붕괴과정에서 생성되는 라돈(Rn-222)은 다른 물질과 화학적으로 결합 또는 부착하지 않는 불활성 기체이고 상대적으로 긴 반감기를 갖고 있기 때문에 충분한 시간 동안 공기중에 머물러 있으므로 다른 자연방사선원에 비하여 라돈과 라돈자손에 의한 일반인의 자연방사선피폭 기여도가 가장 높다(Jamil K. 1997). 이미 세계 여러 나라에서는 라돈피폭에 기인한 건강상의 위해를 인식하여 주택을 비롯한 여러 생활공간의 실내 및 음용수 중의 라돈농도에 대한 대규모적인 측정을 수행하고 있으며, 그 결과 미국 내 상당수의 주택이 미국 환경청에서 권고치(action level)로써 권고하고 있는 150 Bq/m3(실내공기중)와 11.100 Bq/m3(음용수중)응 초과하는 것으로 나타났다(U,S,EPA, 1992).(중략)

• Journal of health informatics and statistics
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• v.42 no.4
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• pp.309-316
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• 2017

Objectives: Radon and its progeny pose environmental risks as a carcinogen, especially to the lungs. Investigating factors affecting indoor radon concentrations and models thereof are needed to prevent exposure to radon and to reduce indoor radon concentrations. The purpose of this study was to identify factors affecting indoor radon concentration and to construct a comprehensive model thereof. Methods: Questionnaires were administered to obtain data on residential environments, including building materials and life style. Decision tree and structural equation modeling were applied to predict residences at risk for higher radon concentrations and to develop the comprehensive model. Results: Greenery ratio, impermeable layer ratio, residence at ground level, daily ventilation, long-term heating, crack around the measuring device, and bedroom were significantly shown to be predictive factors of higher indoor radon concentrations. Daily ventilation reduced the probability of homes having indoor radon concentrations ${\geq}200Bq/m^3$ by 11.6%. Meanwhile, a greenery ratio ${\geq}65%$ without daily ventilation increased this probability by 15.3% compared to daily ventilation. The constructed model indicated greenery ratio and ventilation rate directly affecting indoor radon concentrations. Conclusions: Our model highlights the combined influences of geographical properties, groundwater, and lifestyle factors of an individual resident on indoor radon concentrations in Korea.

• Journal of Radiation Protection and Research
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• v.27 no.2
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• pp.121-126
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• 2002

The work presents a realistic human exposure assessment of indoor radon released from groundwater in a house. At first, a two-compartment model is developed to describe the generation and transfer of radon in indoor air from groundwater. The model is used to estimate radon concentrations profile of indoor air in a house us]ng by showering, washing clothes, and flushing toilets. Then, the study performs an uncertainty analysis of model input parameters to quantify the uncertainty in radon concentration profile. In order to estimate a daily internal dose of a specific tissue group in an adult through the inhalation of such indoor radon, 3 PBPK(Physiologically-Based Pharmaco-Kinetic) model is developed. Combining indoor radon profile and PBPK model is used to a realistic human assessment for such exposure. The results obtained from this study would be used to the evaluation of human risk by inhalation associated with the indoor radon released from groundwater.

• Journal of the Korea Institute of Building Construction
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• v.18 no.1
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• pp.9-15
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• 2018

Radon gas, which is present on the earth, is a primary carcinogen released from rocks, soil, building materials, etc., and exists as a unique gas phase. In order to solve the risk of radon gas, we evaluated the basic performance which can be used as indoor finishing materials in addition to the radon gas reduction properties of the matrix using anthracite. An anthracite used as a conventional filter material was used to produce a matrix, and a test was conducted to replace the gypsum board, which is one of the building materials used in the existing room. As the anthracite replacement ratio increases, flexural failure load strength increases and thermal conductivity tends to decrease. Depending on the thickness of the board, the reduction performance of radon gas shows a slight difference.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.111-112
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• 2017

Radon has been considered the greatest source of exposure within the total radiation exposure of the human body. xposure from radon, which exists in indoor air quality, lacks public perception, Radon, which exists anywhere on earth, is not regarded as a state of attention even if it is above the average level. Indoor radon exposure situations are not intentionally introduced, and essentially the attention and responsibilities of radon exposures are assumed to be in indoor occupants. So, these are caused by common uranium and thorium scattering on Earth, and are brought into the building by fine cracks or exposed indicators of the buildings. Therefore, this study aims to reduce the risk of radon rays and reduce radon, which induces diseases caused by breathing in the body of indoor air pollutants and emitting diseases by emitting alpha rays from the radon gas.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.123-131
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• 2012

As the price of traditional fuels soar, the alternatives are becoming more viable. And manufacturers are promoting the growing viability of electric and biofuel-powered vehicles through longer warranties. Now, these longer green environment (emission)warranties, sometimes called extended warranties or "super warranties," have been adapted. The main result of this paper is to present a new method to approximate a bivariate warranty function by using Radial Basis Function Network with application of Radon Transform and its inverse which is used to reduce the dimension of the warranty space. This method consist of the following stages: First, by using the Radon Transform, the bivariate warranty function can be reduced to one dimensional function. Second, each of the one dimensional functions is approximated by using neural network technique into neural sub-networks. Third, these neural sub-networks are combined together to form the final approximation neural network. Four, by using the inverse of radon transform to this final approximation neural network we get the approximation to the given function. Also, we apply the above method to some green warranty data of automotive vehicle company.

• Journal of Korea Multimedia Society
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• v.12 no.3
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• pp.372-382
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• 2009

When the range of projection angles is limited, tomographic reconstruction suffers from artifacts caused by incomplete data. One can consider a data completion technique, which estimates projection data at unobserved angles using a prior knowledge or mathematical exploration, but the result is often not improved; the improvement by the data completion often undermined by the artifacts by inaccurate estimation, In this paper, we propose an iterative method, which computes projection data at unobserved angles by using the current estimate on the image, links the computed projection data to the observed ones by using the consistence condition of Radon transform, and reconstruct the next estimate on the image by filtered backprojection. The proposed method does not require a prior knowledge on the image, and has much faster approximation rate than the expectation maximization method. The performance of the proposed method was tested through several simulation studies.