• Journal of Radiation Protection and Research
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• v.32 no.1
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• pp.1-8
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• 2007

A model for radiological dose assessment in an urban environment, METRO-K has been developed. Characteristics of the model are as follows ; 1) mathematical structures are simple (i.e. simplified input parameters) and easy to understand due to get the results by analytical methods using experimental and empirical data, 2) complex urban environment can easily be made up using only 5 types of basic surfaces, 3) various remediation measures can be applied to different surfaces by evaluating the exposure doses contributing from each contamination surface. Exposure doses contributing from each contamination surface at a particular location of a receptor were evaluated using the data library of kerma values as a function of gamma energy and contamination surface. A kerma data library was prepared fur 7 representative types of Korean urban buildings by extending those data given for 4 representative types of European urban buildings. Initial input data are daily radionuclide concentration in air and precipitation, and fraction of chemical type. Final outputs are absorbed dose rate in air contributing from the basic surfaces as a function of time following a radionuclide deposition, and exposure dose rate contributing from various surfaces constituting the urban environment at a particular location of a receptor. As the result of a contaminative scenario for an apartment built-up area, exposure dose rates show a distinct difference for surrounding environment as well as locations of a receptor.

• Journal of Radiation Protection and Research
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• v.38 no.2
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• pp.60-67
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• 2013

A diffusion coefficient is an important parameter in the prediction of atmospheric dispersion using a Gaussian plume model, and its modelling approach varies. In this study, dispersion coefficients recommended by the U. S. Nuclear Regulatory Commission's (U. S. NRC's) regulatory guide and the Canadian Nuclear Safety Commission's (CNSC's) regulatory guide, and used in probabilistic accident consequence analysis codes MACCS and MACCS2 have been investigated. Based on the atmospheric dispersion model for a hypothetical accidental release recommended by the U. S. NRC, its influence to atmospheric dispersion factor was discussed. It was found that diffusion coefficients are basically predicted from a Pasquill- Gifford curve, but various curve fitting equations are recommended or used. A lateral dispersion coefficient is corrected with consideration for the additional spread due to plume meandering in all models, however its modelling approach showed a distinctive difference. Moreover, a vertical dispersion coefficient is corrected with consideration for the additional plume spread due to surface roughness in all models, except for the U. S. NRC's recommendation. For a specified surface roughness, the atmospheric dispersion factors showed differences up to approximately 4 times depending on the modelling approach of a dispersion coefficient. For the same model, the atmospheric dispersion factors showed differences by 2 to 3 times depending on surface roughness.

• Journal of Radiation Protection and Research
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• v.28 no.4
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• pp.299-309
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• 2003

In an accidental release of radioactive materials to the environment the contaminative influence of animal products due to the inhalation of air and the ingestion of soil of livestock, both of which are dealt with as minor contaminative pathways in most radioecological models but may not be neglected, was investigated with the improvement of the Korean dynamic food chain model DYNACON Although mathematical models for both contaminative pathways have been established for considering all animal products and incorporated into the model, investigation was limited to milk. As a result, it was found that both pathways are influential in the contamination of milk in the case of an accidental release during the non-grazing period of dairy cows. In the case of an accidental release during the non-grazing period, the inhalation of air was more influential than the ingestion of soil in the early days following an accidental release. While, it was the opposite with the lapse of time. If precipitation is encountered during an accidental release, contaminative influence due to the ingestion of soil was greater compared with the cases of no precipitation, in general, because of a stealer deposition of radionuclides onto the ground. Precipitation during an accidental release was a less influential factor in $^{131}I$ (elemental iodine) contamination compared with the $^{137}Cs\;and\;^{90}Sr$ contaminations. In the case of an accidental release during the grazing period of dairy cows, the contaminative influence due to the inhalation of air was negligible.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.5
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• pp.261-276
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• 2020

This study seeks to find an effective support plan through the success factors recognized in the early stages of startup and those recognized after success by grasping the success factors of successful small business entrepreneurs at each stage from the pre-start stage to the growth stage. To this end, a qualitative study through interviews was conducted with successful convenience store franchisees to derive success factors from the start-up preparation stage to the early stage and growth stage. The success factors of starting a small business were studied in consideration of the characteristics of franchise convenience store startups using the ERI model and the ERIS model applied in the study on the performance of startups. The success factors were studied using the multisite service firm life cycle of Sasser et al.(1978) reflecting the results. As a result of the study, the key factors of successful franchisees were the selection of the location of the first store, the selection of strategic additional stores, and the successful renewal of the contract. Depending on the characteristics of the founder, the enterprising franchisees took an active attitude in selecting strategic locations for additional stores and defending the commercial district, while the relatively conservative franchisees showed an active attitude toward store operation and renewal from a management perspective. In particular, the entrepreneur's mind is important in the preparation stage, and the importance of the entrepreneur's management strategy was discovered in the entire business cycle. Based on the results of this study, this study specifically sought out a start-up plan to effectively apply it to the future growth stage.

• Journal of Radiation Protection and Research
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• v.25 no.1
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• pp.11-19
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• 2000

The sensitivity analysis of input parameters for a dynamic food chain model DYNACON was conducted as a function of deposition date for the long-lived radionuclides $(^{137}Cs,\;^{90}Sr)$. Also, the influence of input parameters for the short and long-terms contamination of selected foodstuffs (cereals, leafy vegetables, milk) was investigated. The input parameters were sampled using the LHS technique, and their sensitivity indices represented as PRCC. The sensitivity index was strongly dependent on contamination period as well as deposition date. In case of deposition during the growing stages of plants, the input parameters associated with contamination by foliar absorption were relatively important in long-term contamination as well as short-term contamination. They were also important in short-term contamination in case of deposition during the non-growing stages. In long-term contamination, the influence of input parameters associated with foliar absorption decreased, while the influence of input parameters associated with root uptake increased. These phenomena were more remarkable in case of the deposition of non-growing stages than growing stages, and in case of $^{90}Sr$ deposition than $^{137}Cs$ deposition. In case of deposition during growing stages of pasture, the input parameters associated with the characteristics of cattle such as feed-milk transfer factor and daily intake rate of cattle were relatively important in contamination of milk.

• Journal of Radiation Protection and Research
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• v.23 no.3
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• pp.149-157
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• 1998

An analysis has been performed to estimate the additional number of workers and the additional collective dose in man-cSv which would be required, nuclear industry-wide as a result of reducing individual dose limit. This analysis can be extended to the reduction in the dose limits recommended by ICRP Publ.60 and BEIR V report as well as the proposed dose limits by regulatory authorities. An industry-wide database was employed in the analysis based on a summary of industry-wide occupational radiation exposure compiled by the Korea Radioisotope Association. Correlation model was employed to compute the affects of setting specific annual individual dose limits. In this study, we have addressed worker non-productivity while in the radiation environment on a parametric or 'sensitivity analysis' basis. This alleviates the need for developing such data underlying a summation of many individual tasks at many nuclear facilities. It has the advantage that very low non-productivity assumptions can readily be defended as conservative, in that it is difficult to approach such low worker non-productivity factors even in the best of environments in any industry. On a per facility basis, for calendar year 1997, the number of workers required would be increased from 231 workers to 269 workers and collective man-cSv dose would be also increased by approximately fourteen percent if the individual dose limit was reduced to 2 cSv/y and an individual worker non-productivity fraction of 0.1 is assumed.

• Journal of Radiation Protection and Research
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• v.27 no.3
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• pp.189-198
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• 2002

The time for evacuation of residents in emergency planning zone(EPZ) of Uljin nuclear site in case of a radiological emergency was estimated with traffic analysis. Evacuees were classified into 4 groups by considering population density, local jurisdictions, and whether they ate residents or transients. The survey to investigate the behavioral characteristics of the residents was made for 200 households and included a hypothetical scenario explaining the accident situation and questions such as dwelling place, time demand for evacuation preparation transportation means for evacuation, sheltering place, and evacuation direction. The microscopic traffic simulation model, CORSIM, was used to simulate the behavior of evacuating vehicles on networks. The results showed that the evacuation time required for total vehicles to move out from EPZ took longer in the daytime than at night in spite that the delay times at intersections were longer at night than in the daytime. This was analyzed due to the differences of the trip generation time distribution. To validate whether the CORSIM model fan appropriately simulate the congested traffic phenomena assumable in case of emergency, a benchmark study was conducted at an intersection without an actuated traffic signal near Uljin site during the traffic peak-time in the morning. This study indicated that the predicted output by the CORSIM model was in good agreement with the observed data. satisfying the purpose of this study.

• Journal of Radiation Protection and Research
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• v.34 no.2
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• pp.87-94
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• 2009

Tritium is the one of the dominant contributors to the internal radiation exposure of workers at pressurized heavy water reactors (PHWRs). This nuclide is likely to release to work places as tritiated water vapor (HTO) from a nuclear reactor and gets relatively easily into the body of workers by inhalation. Inhaled tritium usually reaches the equilibrium of concentration after approximately 2 hours inside the body and then is excreted from the body with a half-life of 10 days. Because tritium inside the body transports with body fluids, a whole body receives radiation exposure. Internal radiation exposure at PHWRs accounts for approximately 20-40% of total radiation exposure; most internal radiation exposure is attributed to tritium. Thus, tritium is an important nuclide to be necessarily monitored for the radiation management safety. In this paper, metabolism for tritium is established using its excretion rate results in urine samples of workers at PHWRs and an effective half-life, a key parameter to estimate the radiation exposure, was derived from these results. As a result, it was found that the effective half-life for workers at Korean nuclear power plants is shorter than that of International Commission on Radiological Protection guides, a half-life of 10 days.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.89-100
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• 2021

The National Cyber Capability Assessment(NCCA) could be used as meaningful information for improving national cyber security policy because it provides information on the elements necessary for strengthening national cyber capabilities and the level of each country. However, there were few studies on improving cyber capabilities using the NCCA result in Korea. Therefore, we analyzed the result of National Cyber Power Index(NCPI) conducted by Belfer Center of Harvard Univ. by applying modified-IPA method to derive cybersecurity policy agendas for Korea. As a result, the need to set agendas on surveillance and offensive cyber capability and improve the effectiveness of policy implementation for intelligence and defense was drawn. Moreover, we suggested need for in-depth study of each policy agenda deduced from preceding research data as a future tasks. And it is expected to increase practical use of NCCA for domestic policy analysis by developing and using our own NCCA model which considered analysis framework proposed in this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.116-126
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• 2021

Ground Component Command (GCC) has been developing operational planning and execution systems to implement "Decisive Integrated Operations", which is the concept of ground operations execution, and achieved remarkable results. In particular, "Simultaneous Offense-Defense Integrated Operations" is developed mainly to neutralize enemies in deep areas and develop favorable conditions for the allies early by simultaneously attacking and defending from the beginning of the war. On the other hand, it is limited to providing scientific and reasonable support for the commander's decision-making process because analyzing the effects of the deep operation with existing M&S systems is impossible. This study developed a model for analyzing the effects of deep operations that can be used in the KJCCS. Previous research was conducted on the effects of surveillance, physical strike, and non-physical strike, which are components of deep operations to find the characteristics and limitations and suggest a research direction. A methodology for analyzing the effects of deep operations reflecting the interactions of components using data was then developed by the GCC, and input data for each field was calculated through combat experiments and a literature review. Finally, the Deep operations Effect CAlculating Model(DECAM) was developed and distributed to the GCC and Corps battle staff during the ROK-US Combined Exercise. Through this study, the effectiveness of the methodology and the developed model were confirmed and contribute to the development of the GCC and Corps' abilities to perform deep operations.