• Journal of Food Hygiene and Safety
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• v.34 no.2
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• pp.199-204
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• 2019

This study aimed to generate a probability distribution model based on temperature data of frozen food storage facility as input variables for microbial risk assessment (MRA). We visited 8 food-handling businesses to collect temperature data from their cold storage warehouses. The overall mean temperature inside the storage facilities was $-20.48{\pm}3.08^{\circ}C$, with 20.4% of the facilities having above $-18^{\circ}C$, with minimum and maximum temperature values of -10.3 and $-25.80^{\circ}C$ respectively. Temperature distributions by space locations of natural and forced convection were $-22.57{\pm}0.84$ and $-17.81{\pm}1.47^{\circ}C$, $-22.49{\pm}1.05$ and $-17.94{\pm}1.44^{\circ}C$, and $-22.68{\pm}1.03$ and $-18.08{\pm}1.42^{\circ}C$ in the upper (2.4~4 m), middle (1.5~2.4 m), and lower (0.7~1.5 m) shelves, respectively. Probability distributions from the temperature data were obtained using the program @RISK. Statistical ranking was determined using goodness of fit to determine the probability distribution model. Our results show that a log-normal distribution [5.9731, 3.3483, shift (-26.4281)] is most appropriate for relative MRA conduction.

• Journal of radiological science and technology
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• v.44 no.4
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• pp.359-365
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• 2021

A heavy particle accelerator is a device that accelerates particles using high energy and is used in various fields such as medical and industrial fields as well as research. However, secondary neutrons and particle fragments are generated by the high-energy particle beam, and among them, the neutrons do not have an electric charge and directly interact with the nucleus to cause radiation of the material. Quantitative evaluation of the radioactive material produced in this way is necessary, but there are many difficulties in actual measurement during or after operation. Therefore, this study compared and evaluated the generated radioactive material in the concrete shield for protons and carbon ions of specific energy by using the simulation code FLUKA. For the evaluation of each energy of proton beam and carbon ion, the reliability of the source term was secured within 2% of the relative error with the data of the NASA Space Radiation Laboratory(NSRL), which is an internationally standardized data. In the evaluation, carbon ions exhibited higher neutron flux than protons. Afterwards, in the evaluation of radioactive materials under actual operating conditions for disposal, a large amount of short-lived beta-decay nuclides occurred immediately after the operation was terminated, and in the case of protons with a high beam speed, more radioactive products were generated than carbon ions. At this time, radionuclides of ⁴⁴Sc, ³H and ²²Na were observed at a high rate. In addition, as the cooling time elapsed, the ratio of long-lived nuclides increased. For nonparticulate radionuclides, ³H, ²²Na, and for particulate radionuclides, ⁴⁴Ti, ⁵⁵Fe, ⁶⁰Co, ¹⁵²Eu, and ¹⁵⁴Eu nuclides showed a high ratio. In this study, it is judged that it is possible to use the particle accelerator as basic data for facility maintenance, repair and dismantling through the prediction of radioactive materials in concrete according to the cooling time after operation and termination of operation.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.173-183
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• 2020

In the midst of the aging of underground facilities in urban areas and anxiety about road excavation safety accidents, the Ministry of Land, Infrastructure and Transport began to build Underground Geospatial Infomation Map from 2015 as part of the 「ground subsidence prevention measures」 and efficient use of underground spaces. So, the scope is spreading every year. The current Underground Geospatial Infomation Map information is web-based and is operated in a desktop environment, so it is true that there are some limitations in its use in a field environment such as an excavation construction site. The Underground Geospatial Infomation Map, built and operated in a web-based environment, is a large-scale 3D data. Therefore, in order to service by transmitting data to the field without delay, it is necessary to lighten the Underground Geospatial Infomation Map data. In addition, the current Underground Geospatial Infomation Map is not unified in data formats such as 3DS and COLLADA, and the coordinate system method is also different in relative coordinates and absolute coordinates. In this study, by analyzing domestic and overseas prior research and technical use cases, a mobile Underground Geospatial Infomation Map data format and a lightweight method were presented, and a technology development was conducted to create a mobile underground space integration map in the presented format. In addition, the weight reduction rate was tested by applying 3D data compression technology so that data can be transmitted quickly in the field, and technology was developed that can be used by decompressing 3D data compressed in the field. finally, it aims to supplement the technology experimentally developed in this study and conduct additional research to produce it as software that can be used in the excavation site and use it.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.3
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• pp.78-84
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• 2011

This study investigated the user's attitude to the supdari(a traditional wooden bridge) itself and the supdari project, and evaluated the quality of user's satisfaction of the bridge in Jeonju-River by importance-performance analysis(IPA). User's evaluation was achieved through questionnaire survey, and total 267 pieces of subjects were used for the analysis. The supdari users didn't realize the supdari construction was performed as a governance project, and didn't consider the supdari as one of landmarks of Jeonju-River. But local people thought that the supdari is one of the traditional and cultural facilities to reminds their hometown's landscapes and the supdari project can make the community network vitalize. Through the IPA, attributes with relative dissatisfaction were 'landscape facilities like small squares and rest area', 'safety facilities like handrails and guardrails' and width of the supdari. To make the supdari as a traditional landmark in Jeonju-River, an open space based on the tradition and ecological education has to be constructed near the bridge. And in the supdari design, especially handrails system and the bridge width has to be improved to enhance the user's safety.

• Journal of Apiculture
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• v.35 no.1
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• pp.9-19
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• 2020

The questionnaire survey for Apis cerana beekeepers and professionals on improved native bee hives was carried out and we compared the temperature, relative humidity(RH), and weight changes of 4 improved hives(Chungju, Miryang, Hanam, and Suwon) from May 1, 2019 to January 31, 2020. Beekeepers need vertical feeder, hive stand, entrance block, and separating panel as hive accessory devices. The average temperatures within brood area were kept constantly (31.3~35.1℃) and the low daily variances of temperature (≤1℃) in Chungju hive among tested hives were observed. The daily temperature variances in the separated space and on the top of winter cluster were not different among 4 hives. In correlation between the temperature of brood area and the number of combs, Chungju hive showed the highest correlation(80.4%) and between the temperature on top of winter clusters and outside temperature, 4 hives showed high positive correlation(76.8~87.1%). RH of brood area(45~60%) in all hives were kept relatively low and constant compared to the outside RH(60~85%). The stablest RH on the top of winter cluster was observed in Suwon hives (65~75%) The highest cumulative weight increase among hives and the high positive correlation(65~67%) between the change of cumulative hive weight and combs number of hives were shown in the Miryang and Chungju. Based on these results, A. cerana bees are able to manage constant temperature and RH within hives area for their colony life, which also effected by the types of hive.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.6
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• pp.275-286
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• 2021

In this study, the analytical solution for diffraction near a vertical detached breakwater was suggested by superposing the solutions of diffraction near a semi-infinite breakwater suggested previously using linear wave theory. The solutions of wave forces acting on front, lee and composed wave forces on both side were also derived. Relative wave amplitude changed periodically in space owing to the interactions between diffracting waves and standing waves on front side and the interactions between diffracting waves from both tips of a detached breakwater on lee side. The wave forces on a vertical detached breakwater were investigated with monochromatic, uni-directional random and multi-directional random waves. The maximum composed wave force considering the forces on front and lee side reached maximum 1.6 times of wave forces which doesn't consider diffraction. This value is larger than the maximum composed wave force of semi-infinite breakwater considering diffraction, 1.34 times, which was suggested by Jung et al. (2021). The maximum composed wave forces were calculated in the order of monochromatic, uni-directional random and multi-directional random waves in terms of intensity. It was also found that the maximum wave force of obliquely incident waves was sometimes larger than that of normally incident waves. It can be known that the considerations of diffraction, the composed wave force on both front and lee side and incident wave angle are important from this study.

• Journal of the Korean Society of Earth Science Education
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• v.14 no.3
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• pp.225-235
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• 2021

The purpose of this study is to obtain implications for the improvement direction of astronomical education methods and development of educational materials or software. In connection with the 5th grade 1st semester elementary science 'Solar System and Stars' unit, elementary pre-service teachers were given a reorganization task to compare the relative distances from the sun to the planets, and then this was analyzed. Pre-service teachers are 11 male and 19 female students in the second year of the music education department at the elementary school teacher training university in B city. The implications of the study results are as follows. First, the 'distance comparison activity using a roll of tissue paper' is suitable for simply comparing the distances from the sun to the planet, but it has limitations in allowing students to experience the vastness of the solar system or inducing student participation-centered classes. Second, it is necessary to develop software materials for elementary school students that can simultaneously reflect the size of the planet and the distance to the planet that can be applied indoors, and also experience the vastness of the solar system, as well as a wide learning space. Third, textbook materials for students have an important influence on the class design of pre-service teachers.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.518-529
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• 2022

In Task C of the DECOVALEX-2023 project, nine institutes from six nations are developing their numerical codes to simulate thermo-hydro-mechanical coupled behavior for the FE experiment performed at Mont Terri underground rock laboratory, Switzerland. Currently, Step 1 for comparing the simulation results to field data is the ongoing stage, and we used the OGS-FLAC simulator for a series of numerical simulations. As a result, temperature increase depending on the heating hysteresis was well simulated, and saturation variation in the bentonite depending on phase change was observed. However, due to the suction overestimation, relative humidity and temperature change in the bentonite and the pressure variation in the Opalinus clay showed a difference compared to the field data. From the observation, it is confirmed that the effect of the bentonite capillary pressure is dominant to the flow analysis in the disposal system. We further plan to draw improved results considering tunnel support material and accurate initial water pressure distribution. Additionally, the thermal, hydrological, and mechanical anisotropy of the Opalinus clay was well simulated. From the simulation results, we confirmed the applicability of the OGS-FLAC simulator in the disposal system analysis.

• Journal of the Korean Regional Science Association
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• v.38 no.2
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• pp.21-41
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• 2022

The purpose of this study is to compare the differences in the subjective quality of life (QoL) perceived by residents in different settlement spaces such as urban vs. rural and Seoul Capital Area (SCA) vs. Non-Capital Area (NCA). Using the data of the 'Quality of Life Satisfaction Survey for Balanced Development' conducted nationwide by the Presidential Committee for Balanced National Development in 2018, a propensity score matching method was introduced to compare the differences between the types of settlement spaces. The results show that no significant difference is found between all the types in satisfaction with local life, and in the case of happiness, rural residents show a higher level than those living in cities. Looking at the quality of life by QoL domain, the QoL of urban residents in SCA is generally the highest in the basic living environment, medical care, and culture/leisure domains, while the QoL of rural residents in the job/income, environment, community, and welfare domains is higher than that of residents of SCA and NCA cities. Interestingly, in no domains NCA cities show their relative strength. These results show the value of rural areas in the face of increasingly prevailing urbanization trends, and suggests that the value of rural areas must be strengthened for rural development. It is necessary to pursue policy efforts such as rural regeneration based on spatial planning in order to respond to the disorganized development that damages the value of the rural environment and landscape and to harmoniously maintain and develop the rural settlement.

• Journal of the Korean Geotechnical Society
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• v.39 no.8
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• pp.29-39
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• 2023

The degree of saturation determines the connectivity of void space and the particle surface. Thus, it greatly affects the electrical conductivity of soils. This study aimed to analyze the electrical conductivities of coarse grains with a high relevance of pore water conduction and fine grains with a high relevance of surface conduction based on the degree of saturation. It also aimed to express the electrical conductivity of unsaturated soils as a combination of surface and pore water conductions using the modified Archie's equation. Samples were prepared in a plastic cell equipped with four electrodes, and the electrical conductivity was measured based on the porosity at various degrees of saturation (40%~100%). The results demonstrate that Archie's equation can be used to express the electrical conductivity of coarse grains, with a saturation exponent of ~1.93 regardless of the pore water conductivity. However, the saturation exponent of fine grains varied considerably with pore water concentration. This variation can be attributed to the relative magnitude of surface conduction with respect to the electrical conductivity of soils at different pore water concentrations. Thus, the degree of saturation has varying effects on pore water conduction and surface conduction. Therefore, different saturation exponents must be used for pore water conduction and surface conduction to predict the electrical conductivity of unsaturated soils using the modified Archie's equation.