• Computers and Concrete
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• v.18 no.6
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• pp.1097-1112
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• 2016

Fire loading causes a critical collapse of RC (Reinforced Concrete) Structures since the embedded steels inside are relative week against high elevated temperature. Several numerical frameworks for fire resistance have been proposed, however they have limitations such as unstable convergence and long calculation period. In the work, 2-D nonlinear FE technique is proposed using Galerkin method for RC structures under fire loading. Closed-form element stiffness with a triangular element is adopted and verified with fire test on three RC slabs with different fire loading conditions. Several simulations are also performed considering fire loading conditions, water contents, and cover depth. The proposed numerical technique can handle time-dependent fire loading, convection, radiation, and material properties. The proposed technique can be improved through early-aged concrete behavior like moisture transport which varies with external temperature.

• Journal of radiological science and technology
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• v.23 no.2
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• pp.39-42
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• 2000

When ordinary sugar is exposed to ionizing radiation, a number of free radical are created in sugar, and Electron Paramagnetic Resonance (EPR) signal appears from the sugar because of the paramagnetic property of free radical. In this paper, EPR signal intensity has been measured in x-ray irradiated sugar for various absorbed doses, irradiated dose up to 50 Gy. The EPR intensity signals are increased as the x-ray irradiation increases. Also, the fading value decreased to about 3% in 30day after the irradiation. Therefore, the sugar is a useful material for emergency dosimeter as the free radical dosimetry with the EPR equipment.

• Communications for Statistical Applications and Methods
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• v.27 no.2
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• pp.201-210
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• 2020

Baseline-category logit random effects models have been used to analyze longitudinal nominal data. The models account for subject-specific variations using random effects. However, the random effects covariance matrix in the models needs to explain subject-specific variations as well as serial correlations for nominal outcomes. In order to satisfy them, the covariance matrix must be heterogeneous and high-dimensional. However, it is difficult to estimate the random effects covariance matrix due to its high dimensionality and positive-definiteness. In this paper, we exploit the modified Cholesky decomposition to estimate the high-dimensional heterogeneous random effects covariance matrix. Bayesian methodology is proposed to estimate parameters of interest. The proposed methods are illustrated with real data from the McKinney Homeless Research Project.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.895-908
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• 2018

As modern science is developed and advanced, examination and number of times using radiation are increasing daily. General diagnostic X-ray generator is installed on stationary form, But X-ray generator was developed because patient who is in the intensive care unit, operation room, emergency room can not move to general x-ray room. What we examine patient by x-ray generator is certainly necessary, So patient exposure is inevitable. but reducing radiation exposure is highly important matter about radiation technology, guardian, patient in the same hospital room, nurse etc. For this reason, rule regarding safety control of diagnostic x-ray generator revised for radiation worker, patient and protector proclaim that mobile diagnostic x-ray shield must placed in case of examine different location excluding operation room, emergency room, intensive care unit. But, radiogical technologist is having a lot of difficulties to examine with mobile x-ray generator, diagnostic x-ray shield partition, image plate and lead apron. So, when we use x-ray generator, we manufacture shield tools can be attached to the mobile x-ray generator On behalf of x-ray shield partition and conduct analysis and in comparison to part of body and distribution of dose rate and find way to reduce radiation exposure through distribution of dose rate of patient within the radiogical technologist, medical team. Mobile x-ray generator aimed at SHIMADZU inc. R-20, We manufactured equipment for shielding x-ray scattered x-ray by installing shielding wall from side to side based on support beam on the mobile x-ray generator. Shielding wall when moving can be folded and designed to expand when examine. Experiment measured five times in each by an angle for dose rate of eyes, thyroid, breast, abdomen and gonad on exposure condition of upper and lower extremity, chest, abdomen which is examined many times by mobile x-ray generator. We used dosimeter RSM-100 made by IJRAD and measured a horizontal dose rate by body part. The result of an experiment, shielding decreasing rate of the front and the rear showed 77 ~ 98.7%. Therefore using self-production shielding wall reduce scattered x-ray occurrence rate and confirm can decrease exposure dose consequently. Therefore, through this study, reduction result which is used shielding wall of self-production will be a role of shielding optimization and it could be answer about reduction of medical exposure recommended by ICRP 103.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.1
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• pp.35-43
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• 1997

Handling the emergency problems such as Chemobyl accident require real time prediction of pollutants dispersion. One-point real time sounding at pollutant source and simple model including turbulent-radiation process are very important to predict dispersion at real time. The stability categories obtained by one-dimensional numerical model (including PBL dynamics and radiative process) are good agreement with observational data (Golder, 1972). Therefore, the meteorological parameters (thermal, moisture and momentum fluxes; sensible and latent heat; Monin-Obukhov length and bulk Richardson number; vertical diffusion coefficient and TKE; mixing height) calculated by this model will be useful to understand the structure of stable boundary layer and to handling the emergency problems such as dangerous gasses accident. Especially, this simple model has strong merit for practical dispersion models which require turbulence process but does not takes long time to real predictions. According to the results of this model, the urban area has stronger vertical dispersion and weaker horizontal dispersion than rural area during daytime in summer season. The maximum stability class of urban area and rural area are 'A' and 'B' at 14 LST, respectively. After 20 LST, both urban and rural area have weak vertical dispersion, but they have strong horizontal dispersion. Generally, the urban area have larger radius of horizontal dispersion than rural area. Considering the resolution and time consuming problems of three dimensional grid model, one-dimensional model with one-point real sounding have strong merit for practical dispersion model.

• Journal of the Korean Society of Radiology
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• v.7 no.3
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• pp.233-238
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• 2013

Chest lateral decubitus radiation exposure PA be carried out in general, but emergency patient or the patient's discomfort in the body examination had a lot of inconvenience. In this study, we compared AP and PA image quality, patient safety, and analysis of the examination effectiveness between the two tests was to evaluate the usefulness. Pleurisy or pneumothorax in patients with suspected or diagnosed chest lateral decubitus radiation exposure 30 consecutive patients (male 20 patients, 10 females) were included in the study. Image quality evaluation method microstructure of lung, wide areas of diagnosis, a clear air-fluid interface, the patient rotate, cardiac shadow and sharp diaphragmatic was based on Department of Radiology specialist, division of pulmonology resident blind test was evaluated by four people. Chest decubitus by radiation exposure the AP and PA position examination the usefulness of comparative analysis Image quality in the AP and PA, whereas there was no significant difference in attitude, Stability of the patient and Radiation's examination efficiency AP position compared to the position of PA scores were higher. PA position does not require a examination may be of AP position in a position to suggest that.

• Journal of Radiation Protection and Research
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• v.36 no.3
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• pp.127-133
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• 2011

In 2007, the International Commission on Radiological Protection (ICRP) published Recommendations of the International Commission on Radiological Protection. Accordingly IAEA safety standards committees have reviewed and revised the BSS. The process of the implementation of the ICRP 103 into Korean radiation protection regulations has been continued. Although the new recommendations retain the fundamental protection principles, the impact of the new ICRP recommendations will necessarily be greater than ever before. ICRP recommends the application of dose constraint in planned situations and reference level in existing & emergency situations for strengthening of the principle of optimization. Dose constraints and reference level play a criterion on the level of individual dose as prospective and source-related values. Therefore it is necessary to apply dose constraints and reference levels to all nuclear and RI&RG facilities in Rep. of Korea. Dose constraints and reference level of occupational exposure will be set-up by the stakeholder itself with the cooperation of regulatory body. In this study, the implementation method was discussed to apply the dose constraints and reference level as the procedure for the optimization, not the tool of the regulation.

• Journal of radiological science and technology
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• v.39 no.1
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• pp.19-26
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• 2016

The radiation has been utilized in a number of fields, even though the use of plenty cause a variety of side effects. This study was confirmed for radiation protective effects of aged garlic to contribute to the prevention of disasters that are radiation exposure. We studied the Complete Blood cell Count(CBC) and the small intestine after feeding aged garlic extract into Sprague Dawley Rat which irradiated X-ray beam 7 and 13 Gy. Garlic extract was administered to the results in the experimental group showed a notable difference in the CBC of platelets (p<0.05), red blood cells (p<0.05) and early damaged white blood cells (p<0.05). In addition, it was confirmed that experimental group's small intestine crypt is more survival than irradiation group significantly. And experimental group has small intestine villi length almost similar to the normal group. result of the aged garlic study will be able to be of great benefit for the radiation relevant emergency management.

• Radiation Oncology Journal
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• v.22 no.4
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• pp.288-297
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• 2004

Puporse: The aims of this study were to evaluate the change of $[^18F]fluoromisonidazole$($[^18F]FMISO$) uptake in C3H mouse squamous cell carcinoma-VII (SCC-VII) treated with mild hyperthermia ($42^{circ}C$) and nicotinamide and to assess the biodistribution of the markers in normal tissues under similar conditions. Methods and Materials: $[^18F]FMISO$ was producedby our hospital. Female C3H mice with a C3H SCC-VII tumor grown on their extremities were used. Tumors were size matched. Non-anaesthetized, tumor-bearing mice underwent control or mild hyperthermia at $42^{circ}C$ for 60 min with nicotinamide (50 mg/kg i.p. injected) and were examined by gamma counter, autoradiography and animal PET scan 3 hours after tracer i.v. injected with breathing room air, The biodistribution of these agents were obtained at 3 h after $[^18F]FMISO$ injection. Blood, tumor, muscle, heart, lung, liver, kidney, brain, bone, spleen, and intestine were removed, counted for radioactivity and weighed. The tumor and liver were frozen and cut with a cryomicrotome into 10- um sections. The spatial distribution of radioactivity from the tissue sections was determined with digital autoradiography. Results: The mild hyperthermia with nicotinamide treatment had only slight effects on the biodistribution of either marker in normal tissues. We observed that the whole tumor radioactivity uptake ratios were higher in the control mice than in the mild hyperthermia with nicotinamide treated mice for $[^18F]FMISO$ ($1.56{\pm}1.03$ vs. $0.67{\pm}0.30$; p=0.063). In addition, autoradiography and animal PET scan demonstrated that the area and intensity of $[^18F]FMISO$ uptake was significantly decreased. Conclusion: Mild hyperthermla and nicotinamide significantly improved tumor hypoxia using $[^18F]FMISO$ and this uptake reflected tumor hypoxic status.

• Journal of Radiation Protection and Research
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• v.24 no.1
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• pp.31-38
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• 1999

A real-time dose assessment system(FADAS : Following Accident Dose Assessment System) has been developed for the real-time accident consequence assessment against a nuclear accident. Field tracer experiment near Younggwang nuclear power plant was performed to improve the accuracy of developed system and to parameterize the site-specific parameters into the FADAS. The mean values and turbulent components of wind profile obtained through field experiment have been reflected to FADAS with site-specific conditions. The simulated results of diffusion model agreed well with the measured data through tracer experiment. The developed system is being used as a basic module of emergency preparedness system in Korea. The diffusion model which can be reflected site-specific parameters will be improved through field experiments continuously.