• Journal of Radiation Protection and Research
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• v.39 no.3
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• pp.150-158
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• 2014

Radiation-related practitioners and radiation-treated patients at medical institutions are inevitably exposed to radiation for diagnosis and treatment. Although standards for maximum doses are recommended by the International Commission on Radiological Protection (ICPR) and the International Atomic Energy Agency (IAEA), more direct and available measurement and analytical methods are necessary for optimal exposure management for potential exposure subjects such as practitioners and patients. Thus, in this study we developed a system for real-time radiation monitoring at a distance that works with existing portable device. The monitoring system comprises three parts for detection, imaging, and transmission. For miniaturization of the detection part, a scintillation detector was designed based on a silicon photomultiplier (SiPM). The imaging part uses a wireless charge-coupled device (CCD) camera module along with the detection part to transmit a radiation image and measured data through the transmission part using a Bluetooth-enabled portable device. To evaluate the performance of the developed system, diagnostic X-ray generators and sources of $^{137}Cs$, $^{22}Na$, $^{60}Co$, $^{204}Tl$, and $^{90}Sr$ were used. We checked the results for reactivity to gamma, beta, and X-ray radiation and determined that the error range in the response linearity is less than 3% with regard to radiation strength and in the detection accuracy evaluation with regard to measured distance using MCNPX Code. We hope that the results of this study will contribute to cost savings for radiation detection system configuration and to individual exposure management.

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.373-381
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• 2014

It is difficult to predict the magnitude of a rockfall with respect to the shape, volume, and weight of the rock mass, as a rockfall exhibits erratic behavior that depends on the slope geometry, such as the height and dip of the slope. In this study, a field survey was conducted on the slopes of Ulleung-Do, South Korea, where rockfalls frequently occur along coastal roads, to classify the mode of rockfalls and estimate their magnitude. This study also analyzed the effects of rockfall behavior on roads by applying a simulation technique. Agglomerate and trachytic rocks distributed across the study area produce rockfalls in a differential weathering rockfall mode and a toppling rockfall mode. In terms of rockfall weight, trachytic rockfalls were 2-3 times heavier than agglomerate rockfalls. An analysis of rockfall behavior from the simulation indicates that the impact energy on the road exceeded the absorbing energy of a standard rockfall protection fence; however, the rockfall was secured when a ring-net was applied.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.259-272
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• 2019

Steel-concrete single-leaf blast-resistant doors are protective structures consisting of a steel box and reinforced concrete slab. By the domestic blast-resistant doors, the structure is not designed efficiently because few studies have examined the effects of variables, such as the blast pressure, rebar ratio, and steel plate thickness on the structural behavior. In this study, the structural behavior of the doors was analyzed using the FE method, and the support rotation and ductility ratio used to classify the structural performance were reviewed. The results showed that the deflection changes more significantly when the plate thickness increases than when the rebar spacing is a variable. This is because the strain energy absorbed by the door is reduced considerably when the plate thickness increases, and as a result, the maximum deflection becomes smaller. According to a comparison of the calculated values of the support rotation and the ductility ratio, the structural performance of the doors could be classified based on the support rotation of one degree and ductility ratio of three. On the other hand, more explosion tests and analytical studies will be needed to classify the damage level.

• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.95-103
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• 2017

A lot of hazardous materials have been used for product processing and utility plant. Many accidents including toxic release, fire and explosions occur in the ammonia related facility and plant. Various safety and environment management program including PSM, SMS, ORA etc. are being implemented for risk management and accident prevention in the production industry. Also much study and research have been carried about risk assessment of accident scenario in the academic and research area. In this paper, firstly risk level was assessed by using a typically used KORA program and LOPA PFD method for the selected ammonia unloading and storage facility. And then risk reduction measures for the risk assessed facility were studied in 3 aspects and some measures were proposed. Those Risk Reduction measures are including a leak detection and emergency isolation, water spray, dilution tank, dike and trench, scattering protection in hardware impovement aspect, and a applicable risk criteria, conditional modifier for existing LOPA PFD, alternative supporting modeling program in risk estimation methodology aspect, and last RBPS(Risk Based Process Safety) program, re-doing of process hazard analysis, management system compliance audit in managerial activity aspect.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.860-868
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• 2013

The purpose of this study is to ensure safety by measuring External radiation dose ratio (ERDR) by traits of patients in many ways after administering radiopharmaceutical($^{18}F$-FDG) for PET Torso scan, and to decrease ERDR of those to RI technologist, caretakers, and those who frequently exposed to radiation by arousing attention to radiation dose. Radiopharmaceutical was administered to 80 patients who conducted PET Torso from January to June, 2013. Radiation dose emitted from the patients was measured according to body shape(BMI), water hydration, height, amount of radiation administration. From the moment immediately after the radiopharmaceutical was administered, ERDR was measured by personal traits of patients. The radiation dose increased in proportion to the administered amount of the radiopharmaceutical, and there was no significant difference depending on the body shape of the patients. When water was supplied and the height was normal, the radiation dose was lower compared with the cases where water was not supplied and height was not normal. There is a need for making efforts to minimize the working time through sufficient education and mock training before those who RI technologist with sources of radiation for complying the radiation safety management rule. And they should minimize the ERDR by wearing a protective gear.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.54-63
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• 2018

In this study, the stability and economic feasibility of a MSE (Mechanically stability earth) wall with a pre-cast concrete pacing panel was investigated for a standard section of highway. Based on the design criteria, the MSE walls of the panel type were designed considering the load conditions of the highway, such as the dead load of the concrete pavement, traffic load, and impact load of the barrier. The length of the ribbed metal strip was arranged at 0.9H according to the height of the MSE walls. Because the length of the reinforcement was set to 0.9H according to the height of the MSE wall, the external stability governed by the shape of the reinforced soil was not affected by the height increase. The factor of safety (FOS) for the bearing capacity was decreased drastically due to the increase in self-weight according to the height of the MSE wall. As a result of examining the internal stability according to the cohesive gravity method, the FOS of pullout was increased and the FOS of fracture was decreased. As the height of the MSEW wall increases, the horizontal earth pressure acting as an active force and the vertical earth pressure acting as a resistance force are increased together, so that the FOS of the pullout is increased. Because the long-term allowable tensile force of the ribbed metal strip is constant, the FOS of the fracture is decreased by only an increase in the horizontal earth pressure according to the height. The panel type MSE wall was more economical than the block type at all heights. Compared to the concrete retaining wall, it has excellent economic efficiency at a height of 5.0 m or more.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.131-145
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• 2019

Korea has set up a radiation emergency planning zone based on the 「Act on Physical Protection and Radiological Emergency」 to protect residents living near nuclear power plants in the event of nuclear disasters. Little research has been conducted on the appropriateness of existing nuclear evacuation facilities because of a general lack of interest in nuclear accidents. This research addresses this gap by analyzing the location adequacy of evacuation facilities in Busan's emergency protection planning area based on vulnerable populations and accessibility analyses. The Gijang-gun which has the greatest risk, shows that only 4.05% of the total urban area was included in the evacuation service area within 5 minutes while only 36.93% of Geumjeong-gu and 37.23% of Haeundae-gu were included in the evacuation-enabled area. In addition, evaluation facilities in the elderly population hotspots were lacking, and there was a wide gap between dongs within the same Gu. Thus, additional evacuation facilities need to be designated and installed considering the spatial equity between areas and safety of both the public and vulnerable populations.

• International Commerce and Information Review
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• v.16 no.1
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• pp.163-183
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• 2014

This paper empirically investigated whether the strategic performance of dependence and commitment on output sector uncertainty based on the data from manufacturing firms in Korea. U.S. Also, the proposed model was proven by the structural equation model with the data gathered from 105 manufacturing firms in Korea, 103 in U.S. The success of the members of channel having limited resources and capabilities depends on how they cope with environment. Especially, it is insispensable for manufacturing firms and distributing firms to build up win win systems when environmental uncertainty is high in the output sector. The findings were as follows. Hypothesis 1 was accepted in all the nations. Hypothesis 2 was accepted in the United States yet not in Korea. Hypothesis 3, 4 was accepted in Korea yet not in the United States. Hypothesis 5 was accepted in every nation as well. In the future, the dependence, commitment and strategic performance of manufacturing and distribution firms should be investigated from a mutual perspective, and additional data should be obtained by selecting more subjects. As for environmental uncertainty, the uncertainty of distribution environments as well as output sector uncertainty should equally be investigated by making a comparative analysis.

• Journal of dental hygiene science
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• v.15 no.4
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• pp.399-406
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• 2015

The purpose of this study was to investigate the performance of dental infection control. This survey was performed on 158 of the dental hygienist in certain areas. The research was performed using a self-reported questionnaire and interview method from June to July, 2014. The collected data was analyzed by PASW Statistics ver. 18.0. Guideline of infection management, infection controller, regular infection control training, Sterilization of the handpiece/per head resulted 57~74% for dental hospital. It was higher than 13~20% for dental clinics (p<0.05). Infection control guidelines and vaccination recognition of dental were more performed in dental hospital. Patient's hand hygiene performed, tooth brushing before treatment, cross infection educational experience was less than 20%, research cooperation of medical history was over 90% (p<0.05). Performing rate of the dental hospital workers were investigated higher in protective personal devices, infection control of treatment room. A correlation analysis about institutional support, infection control of dental hygienists, patients with infection control cooperation showed a positive correlation statistically significant. Infection control can be enhanced when the medical staff, the patient, the organization combined cognitive and practice. Dental hygienist is required to recognize and practice the infection control guidelines through continuing education.

• The Journal of Korean Society for Radiation Therapy
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• v.15 no.1
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• pp.11-18
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• 2003

The concrete is usually used to build a radiation therapy facility and the enough concrete thickness for high energy x-ray beam is about 1 meter. But if the space is not enough to build a radiation therapy facility with concrete, the substitute for concrete is needed, and the Ledite can be a good substitute for concrete. In this study, we compared the Ledite with the concrete. The comparing list are the needed shielding thickness, the period of construction and the cost.