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Radiation-related occupational cancer and its recognition criteria in South Korea
Songwon Seo,Dalnim Lee,Ki Moon Seong,Sunhoo Park,Soo-Geun Kim,Jong-Uk Won,Young Woo Jin 대한직업환경의학회 2018 대한직업환경의학회지 Vol.30 No.-
Ionizing radiation is a well-known carcinogen, and is listed as one carcinogenic agent of occupational cancer. Given the increase in the number of workers exposed to radiation, as well as the increase in concern regarding occupational cancer, the number of radiation-related occupational cancer claims is expected to increase. Unlike exposure assessment of other carcinogenic agents in the workplace, such as asbestos and benzene, radiation exposure is usually assessed on an individual basis with personal dosimeters, which makes it feasible to assess whether a worker’s cancer occurrence is associated with their individual exposure. However, given the absence of a threshold dose for cancer initiation, it remains difficult to identify radiation exposure as the root cause of occupational cancer. Moreover, the association between cancer and radiation exposure in the workplace has not been clearly established due to a lack of scientific evidence. Therefore, criteria for the recognition of radiation-related occupational cancer should be carefully reviewed and updated with new scientific evidence and social consensus. The current criteria in Korea are valid in terms of eligible radiogenic cancer sites, adequate latent period, assessment of radiation exposure, and probability of causation. However, reducing uncertainty with respect to the determination of causation between exposure and cancer and developing more specific criteria that considers mixed exposure to radiation and other carcinogenic agents remains an important open question.
Radiation-related occupational cancer and its recognition criteria in South Korea
Seo, Songwon,Lee, Dalnim,Seong, Ki Moon,Park, Sunhoo,Kim, Soo-Geun,Won, Jong-Uk,Jin, Young Woo BioMed Central 2018 Annals of occupational and environmental medicine Vol.30 No.1
<P>Ionizing radiation is a well-known carcinogen, and is listed as one carcinogenic agent of occupational cancer. Given the increase in the number of workers exposed to radiation, as well as the increase in concern regarding occupational cancer, the number of radiation-related occupational cancer claims is expected to increase. Unlike exposure assessment of other carcinogenic agents in the workplace, such as asbestos and benzene, radiation exposure is usually assessed on an individual basis with personal dosimeters, which makes it feasible to assess whether a worker’s cancer occurrence is associated with their individual exposure. However, given the absence of a threshold dose for cancer initiation, it remains difficult to identify radiation exposure as the root cause of occupational cancer. Moreover, the association between cancer and radiation exposure in the workplace has not been clearly established due to a lack of scientific evidence. Therefore, criteria for the recognition of radiation-related occupational cancer should be carefully reviewed and updated with new scientific evidence and social consensus. The current criteria in Korea are valid in terms of eligible radiogenic cancer sites, adequate latent period, assessment of radiation exposure, and probability of causation. However, reducing uncertainty with respect to the determination of causation between exposure and cancer and developing more specific criteria that considers mixed exposure to radiation and other carcinogenic agents remains an important open question.</P>
서송원(Songwon Seo),민옥기(Oakkey Min) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.9
SPH is an appealing and valuable computational tool using no background mesh, especially for high deformation events such as impact. But, although research has widely done since invented in 1977, this method still have several problems-lacking consistency, tensile instability and especially boundary condition treatment. This paper review current works for the method of imposing boundary conditions and test several model to certify a validity of its methods. It is compared a method using a ghost particle with that using a boundary condition about a symmetric model. Numerical tests are shown a reasonable result when impose a traction or velocity constraint to the models by equations of boundary constraint condition.
SPH에서 임의 형상의 강체면에 대한 탄소성 접촉 해석
서송원(Songwon Seo),이재훈(Jaehoon Lee),민옥기(Oakkey Min) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4
There is few research about contact problem for a rigid surface with an arbitrary shape in SPH. The variational equation based on the virtual work principle is derived and its solution is obtained by the penalty method. It is proposed a new method that can determine the parameters for a penetration and a penetration rate used in the penalty method. The reproducing condition is adopted to correct the deficiency of kernel on the boundary. In order to calculate a penetration of particles, after checking boundary particles for deformable body boundary normal vectors were determined on the rigid surface. Numerical simulations for models which have rigid surface with an arbitrary shape were conducted to validate the proposed method in 2D. The results of those analysis represent that the contact algorithm proposed in this study works properly.
서송원(Seo Songwon),민옥기(Min Oakkey) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
There is few research about contact problem in SPH because it is primarily suitable to analyze the large deformation problem. However, an elasto-plastic problem with small deformation need to be considered about contact characteristics. The numerical formulating methods for SPH is induced to be able to abtain solutions based on a varitional method in contact problem. The contact algorithm presented is applied to the elastic impact problem in ID and 2D. The results show that an imaginary tension and a numercal instability which happen in inpacting between different materials can be removed and contact forces which could not have been calculated are able to obtain.
Dynamic Shear Stress of Tough-Pitch Copper at High Strain and High Strain-Rate
Moon Wonjoo,Seo Songwon,Lim Jaeyoung,Min Oakkey 대한기계학회 2002 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.16 No.11
Dynamic shear tests for the tough-pitch copper at high strain and high strain rate was performed. The Split Hopkinson Pressure Bar (SHPB) compression test system was modified to yield a shear deformation in the specimen. Hat-shaped specimens for the tough-pitch copper were adopted to generate high strain of γ=3 ~4 and high strain-rate of γ=10⁴/s. The dynamic analysis by ABAQUS 5.5/EXPL1CIT code verified that shear zone can be localized in hat-shaped specimens. A proper impact velocity and the axial length of the shear localization region were determined through the elastic wave analysis. The displacement in a hat-shaped specimen is limited by a spacer ring which was installed between the specimen and the incident bar. The shear bands were obtained by measuring the direction of shear deformation and the width of deformed grain in the shear zone. The decrease of specimen length has been measured on the optical displacement transducer. Dynamic shear stress-strain relations in the tough-pitch copper were obtained at two strain-rates.<br/>
SPH 기법을 이용한 고속충돌을 받는 복합 적층판의 해석
이재훈(Jaehoon Lee),서송원(Songwon Seo),이인규(Ingyu Lee),민옥기(Oakkey Min) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
This paper reports experimental results and numerical simulations of high velocity impact on laminated composite plates reinforced with graphite/epoxy. To describe material behavior under high velocity impacts, a 3-D anisotropic elasto-plasticity constitutive model, an equation of state and a failure criterion for unidirectional composites have been used. The above physics were incorporated into the SPH. The numerical simulation was carried out for a steel projectile striking to laminated graphite/epoxy composite plate targets with different layup configurations. Good correlation between numerical simulation and experimental results was achieved, both in terms of deformation and damage of the laminates.
Seong, Ki Moon,Seo, Songwon,Lee, Dalnim,Kim, Min-Jeong,Lee, Seung-Sook,Park, Sunhoo,Jin, Young Woo The Korean Academy of Medical Sciences 2016 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.31 No.1
<P>Inevitable human exposure to ionizing radiation from man-made sources has been increased with the proceeding of human civilization and consequently public concerns focus on the possible risk to human health. Moreover, Fukushima nuclear power plant accidents after the 2011 East-Japan earthquake and tsunami has brought the great fear and anxiety for the exposure of radiation at low levels, even much lower levels similar to natural background. Health effects of low dose radiation less than 100 mSv have been debated whether they are beneficial or detrimental because sample sizes were not large enough to allow epidemiological detection of excess effects and there was lack of consistency among the available experimental data. We have reviewed an extensive literature on the low dose radiation effects in both radiation biology and epidemiology, and highlighted some of the controversies therein. This article could provide a reasonable view of utilizing radiation for human life and responding to the public questions about radiation risk. In addition, it suggests the necessity of integrated studies of radiobiology and epidemiology at the national level in order to collect more systematic and profound information about health effects of low dose radiation.</P>