• Analytical Science and Technology
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• v.19 no.4
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• pp.290-300
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• 2006

Disinfection by-products(DBPs), such as volatile trihalomethanes and the nonvolatile organochlorine acids, created by chlorination have been extensively studied. However MX which contributes 20-50% of the mutagenic activity in drinking water began to people's attention since 1990. Its chemical name is 3-chloro-4-dichloromethyl-5-hydroxy-2(5H)-furanone. According to WHO guidelines its concentration should be controlled, but its value has not been set up. Due to analytical difficulties in measuring this compound at such a low concentrations and lack of information on toxicity to human. Because concentration (ng/L) of MX in drinking water is low traditional testing methods are ineffective. Therefore this study compared LLE and SPE and have chosen SPE to improve preconcentration. MX has been identified in chlorinated drinking water samples in several countries but not in korea Therefore this study analyzed concentration of MX in different water sources and in spring water. This study examined the causes of changing MX content. Chlorine dosage, seasons, water temperature and distance from the source was all discoverd to be relavant. MX was analyzed in various treatment to find optimum disinfection methods. The outcome was that the concentration of MX was minimized when using biological activated carbon-O3 and granular activated carbon.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.3
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• pp.122-138
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• 2023

Today, fishing villages are on the verge of extinction due to severe aging within the population and outward migration. Recent projects and studies targeting fishing villages viewed the fishing villages from an outsider-centered perspective, without a local-centered understanding of the village as a daily living space. Therefore, to understand the settlement environment of fishing villages, this study analyzed empirical data on the usage behavior of fishing village residents to gain insight into the characteristics of the outdoor space uses of residents in fishing villages. In this regard, a face-to-face survey was conducted among residents, and a village map drawn by the villagers showedthe spatial perception of the villagers. Empirical data on the behavior of fishing villagers using the village space was collected and analyzed through GPS. The study results suggested that residents of fishing villages tend to focus on productive activities, such as fishing, leading to a lack of awareness of other leisure activities and spaces. This monotonous pattern of space utilization within the village appears to stem from an absolute lack of available facilities within the target area. Therefore, in future village regeneration projects aimed at improving the quality of life for residents in fishing villages, it is essential to consider the residents' perception and utilization of space as a priority. The results of this study can be considered valuable foundational data for understanding the utilization of spaces within fishing villages and can be effectively utilized in planning initiatives to enhance quality of life.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4B
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• pp.389-398
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• 2006

The present study compositely applied the self-organizing map (SOM), which is a kind of artificial neural networks (ANNs), and the back propagation algorithm (BPA) for the rainfall-runoff prediction model taking account of the irregular variation of the spatiotemporal distribution of rainfall. To solve the problems from the previous studies on ANNs, such as the overestimation of low flow during the dry season, the underestimation of runoff during the flood season and the persistence phenomenon, in which the predicted values continuously represent the preceding runoffs, we introduced SOM theory for the preprocessing in the prediction model. The theory is known that it has the pattern classification ability. The method proposed in the present research initially includes the classification of the rainfall-runoff relationship using SOM and the construction of the respective models according to the classification by SOM. The individually constructed models used the data corresponding to the respectively classified patterns for the runoff prediction. Consequently, the method proposed in the present study resulted in the better prediction ability of runoff than that of the past research using the usual application of ANNs and, in addition, there were no such problems of the under/over-estimation of runoff and the persistence.

• 한국노년학
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• v.39 no.4
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• pp.895-902
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• 2019

This study reviewed the diagnosis accuracy and evaluation criteria of the fall risk assessment questionnaire that proved validity through factor analysis in previous studies. The purpose of this study was to diagnose high-risk groups and propose personal fall risk profiles for the Korean community-dwelling elderly. The participants of this study were 439 elderly people living in S, U, B, and Y cities Korea (mean age 75.0 ± 5.7 years). Receiver operating characteristic analysis was conducted to review the accuracy of the fall risk assessment and evaluation criteria of the FRA. The results showed that the four sub-factors of the FRA: 'Potential for fall', 'Disease and physical symptoms', 'Environment' and 'Physical function', can effectively diagnose the fall risk of the community-dwelling elderly. The evaluation criteria was presented based on the sensitivity and specificity results. In addition, as a result of analyzing the patterns by the sub factors of the fall risk, the high-risk group accounted for 80% of the elderly who had problems with two or more factors. Therefore, the four sub-factors of FRA can effectively diagnose the fall risk level, and could be present individual fall risk profiles based on the evaluation criteria.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.311-325
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• 2023

This study was conducted to analyze the habitat suitability of the major honey trees including Kalopanax septemlobus Koidz., Prunus spp., Tilia spp., and Styrax obassia Siebold & Zucc. indigenous to mountain Gariwang and Yumeong using the machine learning approach (i.e., MaxEnt model). The AUC values of the model predictions were mostly above 0.7, and the results of the response curves showed that the environmental drivers that had effects on the habitat suitability of the major honey trees were elevation, mean annual precipitation, and mean annual temperature. These results indicate that climatic drivers along the elevation gradient are the main environmental drivers in explaining the distribution patterns of the major honey trees. In addition, the results of the response curves of Prunus spp. and Styrax obassia Siebold & Zucc. differed slightly in terms of slope and mean annual solar radiation as the main environmental drivers. The results of this study will be valuable for the establishment of honey tree forests and management plans for the natural and artificial forests in South Korea, as well as for the mapping the distribution of honey trees. Further studies at different regional levels, reflecting biotic drivers, will be needed to expand the production of honey and pollen at different strata and to produce honey annually.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.5
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• pp.19-29
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• 2023

The accident rate in South Korea is simply classified according to the road type and the number of lanes, but other countries apply various factors affect accidents. In this study, national highways where accidents occurred were divided into urban, rural, older, and modern roads using TAAS(Traffic Accident Analysis System) data, and a model of accident costs savings is suggested. As a result of analyzing 1,416.2 km, the fatality rate(person/100mil-vehicle·km) was 4.21 for urban-older, 1.37 for urban-modern, 2.18 for rural-older, and 0.99 for rural-modern roads. The rates of urban roads had a higher result than rural. The injury rate(person/100mil-vehicle·km) for urban-older was 182.63, that for urban-modern was 103.42, that for rural-older was 67.44, and that for rural-modern road was 42.96, which showed a similar pattern to fatality rates. Accident rates of a modern road were much lower than the KDI Guideline. The benefit of applying the result of this study was calculated and the valuation of accident costs savings is increased from 0.6% to 14.1%, while B/C is improved from 0.626 to 0.724.

• The Journal of Engineering Geology
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• v.33 no.4
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• pp.555-571
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• 2023

Due to South Korea's concentrated summer rainfall, constituting 70% of the annual total, landslides frequently occur during the rainy season, necessitating accurate prediction methods to mitigate associated damage. In this study, a reduced-scale and full-scale slope was configured using weathered granite soil to find the possibility of establishing measurement management criterias through landslide reproduction. The experiment focused on matric suction, analyzing changes in ground properties and failure patterns caused by rainfall infiltration. Subsequently, an unsaturated infinite slope stability analysis was conducted. By calculating the failure time when the safety factor falls below 1 for each experiment, landslide prediction was demonstrated to be possible, approximately 17 minutes prior for the reduction-scale experiment and 6.5 hours for the full-scale experiment. These findings provide useful data for establishing Korean soil slope measurement management criteria that consider the characteristics of weathered granite soil.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.402-408
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• 2023

Consumer interest in food nutrition continues to grow; however, research on consumer preferences related to nutrition remains limited. In this study, big data analysis was conducted using keyword logs collected from the national information service, the Korean Food Composition Database (K-FCDB), to determine consumer preferences for foods of nutritional interest. The data collection period was set from January 2020 to December 2022, covering a total of 2,243,168 food name keywords searched by K-FCDB users. Food names were processed by merging them into representative food names. The search frequency of food names was analyzed for the entire period and by season using R. In the frequency analysis for the entire period, steamed rice, chicken, and egg were found to be the most frequently consumed foods by Koreans. Seasonal preference analysis revealed that in the spring and summer, foods without broth and cold dishes were consumed frequently, whereas in fall and winter, foods with broth and warm dishes were more popular. Additionally, foods sold by restaurants as seasonal items, such as Naengmyeon and Kongguksu, also exhibited seasonal variations in frequency. These results provide insights into consumer interest patterns in the nutritional information of commonly consumed foods and are expected to serve as fundamental data for formulating seasonal marketing strategies in the restaurant industry, given their indirect relevance to consumer trends.

• Korean Journal of Culture and Social Issue
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• v.14 no.2
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• pp.41-61
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• 2008

This study was performed to investigate the North Korean defectors's depression through the CES-D and a projective test simultaneously. So 40 North Korean defectors and 40 South Koreans participated in this study. The results are the following. First, the North Korean defectors demonstrated more higher CES-D scores than the South Koreans, while there were not significant differences in the Rorschach depression-related indexes, DEPI, CDI, S-CON between two groups. Second, at the analysis of the sex difference effect, women among the North Korean defectors showed the most high CDI index scores. In addition, we analyzed the mean differences between two groups for morbid content, shading response, achromatic response, human movement response, form dimension response, Lamda, and the number of total response. However, there are not significant differences between two groups for those variables, except for form dimension(FD) response. It suggested the probability that the North Korean women defectors could experience more psychological distress underlyingly than the North Korean men defectors. Third, most importantly, the correlation between CES-D and DEPI in the Rorschach test was significantly different in the two groups(the North Korean defectors and the South Koreans). In conclusion, the self-report of the North Korean defectors on depression could be exaggerated. So we should be cautious to interpret the self report results of the North Korean defectors.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.253-261
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• 2024

Olivine, a major mineral in the upper mantle with strong intrinsic elastic anisotropy, plays a crucial role in seismic anisotropy in the mantle, primarily through its lattice preferred orientation (LPO). Despite this, the influence of the microstructure of mylonitic rocks on seismic anisotropy remains inadequately understood. Notably, there is a current research gap concerning seismic anisotropy directly inferred from mylonitic peridotite massifs in Korea. In this study, we introduce the deformation microstructure and LPO of olivine in the mantle shear zone. We calculate the characteristics of seismic anisotropy based on the degree of deformation (proto-mylonite, mylonite, ultra-mylonite) and establish correlations between these characteristics. Our findings reveal that the seismic anisotropy resulting from the olivine LPO in the ultra-mylonitic rock appears to be the weakest, whereas the seismic anisotropy resulting from the olivine LPO in the proto-mylonitic rock appears to be the strongest. The results demonstrate a gradual decrease in seismic anisotropy as the fabric strength (J-index) of olivine LPO diminishes, irrespective of the specific pattern of olivine's LPO. Moreover, all samples exhibit a polarization direction of the fast S-wave aligned subparallel to the lineation. This suggests that seismic anisotropy originating from olivine in mylonitic peridotites is primarily influenced by fabric strength rather than LPO type. Considering these distinctive characteristics of seismic anisotropy is expected to facilitate comparisons and interpretations of the internal mantle structure and seismic data in the Yugu area, Gyeonggi Massif.