• The Journal of Engineering Geology
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• v.17 no.3
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• pp.359-365
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• 2007

Freezing and thawing cycle is one of the major weathering-induced factors in the mechanical weathering of the rock mass. This natural process accelerates rock weathering process by breaking down the parent rock materials and makes soil or weathered rock formation in a rock slope surface zone. It can also cause reduction of the shear strength in slopes. It is important to calculate the deterioration depth caused by freezing-thawing for a slope stability analysis. In this study, deterioration depths of rock slope due to freezing-thawing were calculated using the 1-D heat conductivity equation. The temperature distribution analysis was also carried out using collected temperature distribution data for last five years of several major cities in Korea. The analysis was performed based on the distributed rock types in study areas. Thermal conductivities, specific heats and densities of the calculation rocks are tested in the laboratory. They are thermal properties of rocks as input parameters for calculating deterioration depths. Finally, the paper is showing the calculated deterioration depths of each rock type slopes in several major cities of Korea.

• Korean Journal of Environment and Ecology
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• v.26 no.1
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• pp.1-10
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• 2012

The habitats characteristics of Polypodium vulgare L. in Ulleung-do were investigated to compile basic data for conservation and restoration. Natural habitats were located at altitudes of 410~748m with inclinations of $12{\sim}80^{\circ}$. Sixty six vascular plants were identified from 10 quadrats in 4 habitats. Dominant species among the woody plants, based on importance value, were Acer pictum subsp. mono(49.52%) in the tree (T1) layer, Sorbus amurensis(28.99%) in the subtree (T2) and Schizophragma hydrangeoides(51.99%), Ligustrum foliosum(8.82%), Fagus engleriana(7.25%) in the shrub (S) layer. Importance value for members of the herb (H) layer were as follows: Polypodium vulgare 23.23%; Maianthemum dilatatum 9.65%; Phryma leptostachya var. asiatica 9.23%; Dryopteris crassirhizoma 8.40%; Carex shimidzensis 6.75% and Dystaenia takesimana 5.42%. The importance value of the last five species were high, so they were at affinity with Polypodium vulgare in their habitats. Species diversity was 1.18, and dominance and evenness were found to be 0.11 and 0.84, respectively. The soil types were sandy loam. Average field capacity was 30.42%, and the organic matter and pH were 17.95%, and 4.70. Correlation coefficients based on environmental factors, vegetation and soil analysis were showed that positive correlations between species diversity and species richness, whereas between species diversity and dominance, coverage of Polypodium vulgare and species richness were showed negative correlations.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.382-388
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• 2014

This study selected five observational stations in the normal direction of Jinu-do(island) shoreline and observed water temperature, electrical conductivity and pressure from March, 2012 to January, 2013(about 11 months) and attempted to see the variation characteristics of ground watertable. This study wants to know : 1) External environment force factors(tide, climate, wave etc.) affecting ground watertable variation through time series and correlation analysis. 2) Spatial variations of ground watertable and electrical conductivity change by storm event. First, we found that the station at the intertidal zone was strongly affected by wave and tide level and the stations at sand dune and vegetation zone was affected by precipitation and tide level through time series data and correlation analysis. Second, during the storm event, we found that ground watertable and electrical conductivity are stabilized at the start line of sand dune and vegetation zone and transition zone between freshwater layer and seawater layer exists in the experiment area and is about 50~70 m from coastline of the south side of Jinu-do(island).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.409-420
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• 2016

The aim of this study was to develop and validate an instrument to measure the separation anxiety of mothers who use child care facilities. The scale was developed as follows: initial items generated, validity and reliability tests performed, and final items extracted. The initial items were developed through a literature review and interviews. The content validity was verified by five experts. Using a final questionnaire, the data was collected from 204 mothers who used child care facilities with a convenient sampling method. The construct validity was evaluated by item analysis, exploratory factor analysis and confirmatory factor analysis. The results of confirmatory and exploratory factor analyses showed that the separation anxiety consisted of 6 factors: the mother's guilty feelings (5-items), safety of child care facilities (5-items), trust of teachers (5-items), child's anxiety (4-items), interaction anxiety with the child (4-items), and management of child care facilities (3-items). The separation anxiety scale for mothers using child care facilities consisted of 26 items. The reliability of the developed scale was examined. The Cronbach's ${\alpha}$ coefficient was 0.93. These results show that this scale is a valid and reliable instrument for measuring the separation anxiety level of mothers who use child care facilities.

• The Korean journal of internal medicine
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• v.33 no.6
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• pp.1093-1102
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• 2018

Background/Aims: The aim of this study was to investigate parameters that predict radiation-induced liver disease (RILD) following stereotactic body radiotherapy (SBRT) in patients with hepatocellular carcinoma (HCC) and to identify the clinical significance of RILD. Methods: We retrospectively reviewed the medical records of 117 HCC patients who were treated by SBRT from March 2011 to February 2015. RILD was defined as elevated liver transaminases more than five times the upper normal limit or a worsening of Child-Pugh (CP) score by 2 within 3 months after SBRT. All patients were assessed at 1 month and every 3 months after SBRT. Results: Median follow-up was 22.5 months (range, 3 to 56) after SBRT. RILD was developed in 29 of the 117 patients (24.7%). On univariate analysis, significant predictive factors of RILD were pretreatment CP score (p < 0.001) and normal liver volume (p = 0.002). Multivariate analysis showed that CP score was a significant predictor of RILD (p < 0.001). The incidence of RILD increased above a CP score of 6 remarkably. The rate of recovery from RILD decreased significantly above a CP score of 8. Survival analysis showed that CP score was an independent prognostic factor of overall survival (p = 0.001). Conclusions: CP score is a significant factor to predict RILD in patients with chronic liver disease. RILD can be tolerated by patients with a CP score ${\leq}7$. However, careful monitoring of liver function is needed for patients with a CP score 7 after SBRT.

• Journal of the Society of Disaster Information
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• v.15 no.1
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• pp.109-120
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• 2019

Purpose: This study is the analysis of the relationship between the physical safety of the urban spaces and the aging in place tendency of the elderly. Method: For analysis, the physical safety of the urban space is divided into four elements: outdoor space and building safety, pedestrian safety, transportation safety and living safety, and for aging in place, the 5-point Likert scale was used. A questionnaire survey was conducted for 411 elderly people aged 65 or older living in Seoul for each of the five urban community in Seoul. Results: 78.6% of the respondents answered that they are good at continuing to live in the present living area, the elderly living in Seoul has the high tendency of aging in place. The ratio of respondents who answered that good at living continuedly is in the order of southeast, northwest, southwest, northeast, and downtown. Conclusion: When the percentage of respondents who answered that they are good at staying in the current living area is high, not only the overall physical safety but also the average of the physical safety factors of the urban space are also high, physical safety of urban spaces is a factor affecting aging in place. Based on the results of the study, it can be applied as a method to create a safe city in the process of city development or urban renewal in the future.

• Journal of Environmental Impact Assessment
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• v.30 no.4
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• pp.237-246
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• 2021

The similarity of hourly PM₁₀ and PM_2.5 concentration profiles of the atmospheric monitoring stations in Gyeonggi-do was evaluated through the multilateral analysis between stations. The existing category for most stations in the regions shows relatively low Pearson correlation values of 0.68 and 0.7 for PM₁₀ and PM_2.5 on average respectively, and some monitoring stations revealed high relationships over 0.8 to other regions. Since the current regions are mainly categorized by cluster analysis based on the number of occurrence of high concentration events and geological factors, it is necessary to reclassify them by concentration characteristics for precise fine dust management. In accordance, multi-dimensional scaling being able to visualize could categorize the regions based on regional emission contribution rate and hourly fine dust concentration. As a result of the current analysis, PM₁₀ and PM_2.5 could be reclassified into five regions and fourregions, respectively.

• Journal of the Korean earth science society
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• v.44 no.1
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• pp.79-89
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• 2023

The purpose of this study was to investigate the effects of engineering design-based ocean cleanup classes on STEAM attitudes and creative engineering problem-solving dispositions. Furthermore, during this process, we tried to determine interesting points that students encountered in engineering design-based classes. For this study, a science class with six lessons based on engineering design was developed and reviewed by a professor who majored in engineering design, along with five engineering design experts with a master's degree or higher. The subject of the class was selected as the design and implementation of scientific and engineering measures to reduce marine pollution based on the method implemented in an actual Ocean Clean-up Project. The engineering design process utilized the engineering design model presented by NGSS (2013), and was configured to experience redesign through the optimization process. To verify effectiveness, the STEAM attitude questionnaire developed by Park et al. (2019) and the creative engineering problemsolving propensity test tool developed by Kang and Nam (2016) were used. A pre and post t-test was used for statistical analysis for the effectiveness test. In addition, the contents of interesting points experienced by the learners were transcribed after receiving descriptive responses, and were analyzed and visualized through degree centrality analysis. Results confirmed that engineering design in science classes had a positive effect on both STEAM attitude and creative engineering problem-solving disposition (p< .05). In addition, as a result of unstructured data analysis, science and engineering knowledge, engineering experience, and cooperation and collaboration appeared as factors in which learners were interested in learning, confirming that engineering experience was the main factor.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.55-61
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• 2023

In this study, a basic research was conducted to establish a maintenance plan considering the environmental factors and deterioration characteristics of port facilities. The precise safety diagnosis reports for Incheon and Busan port facilities were referenced to examine the extent of deterioration and damage. The relationship with the degradation environmental assessment presented in the current guidelines was also analyzed. The analysis of the damage level of Incheon and Busan port facilities revealed that Incheon Port exhibited approximately three times higher damage rate compared to Busan Port. In the case of Incheon Port, reinforcement corrosion and external damage showed similar proportions, while in Busan Port, reinforcement corrosion had a higher proportion compared to external damage. On the other hand, when comparing with the degradation environmental assessment presented in the guidelines, it was found that there were some limitations in performing quantitative evaluation based on the guidelines for assessing port facilities. Therefore, an analysis based on tidal range was conducted by referring to existing literature. The analysis of tidal range in Incheon and Busan regions showed that Incheon had approximately five times higher difference compared to Busan. It is considered that this can be utilized as a differentiated item from existing degradation environmental assessment criteria.

• Knowledge Management Research
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• v.25 no.2
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• pp.95-114
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• 2024

Because it is difficult to respond to a constantly changing environment with individual ability and creativity alone, many organizations are forming teams and seeking ways to make the teams more active. Team learning behavior allows team members to and create better performance based on such accumulated knowledge and experience within a team. In particular, the process of team learning not only explicit and formalized knowledge but also implicit and informal experiences is important from the perspective of knowledge management. However, there were limitations in utilizing research results on team learning behavior because the concepts were fragmented and the measurements were different for each researcher. In this study, an integrated model was presented by examining concepts related to team learning behaviors. Moreover, the measurement model of team learning behaviors was validated for the Korean context. The measurement model consisted of five factors: sharing and elaboration, constructive conflict, team reflection, team activity, and storage and utilization. This tool was confirmed through exploratory factor analysis and confirmatory factor analysis. The results of this study are expected to have implications for team researchers and practitioners who diagnose and improve the level of team learning behavior within an organization.