• The Journal of Engineering Geology
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• v.13 no.3
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• pp.293-308
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• 2003

New results about the crustal structure down to a depth of 60 km beneath North Korea were obtained using the seismic tomography method. About 1013 P- and S-wave travel times from local earthquakes recorded by the Korean stations and the vicinity were used in the research. All earthquakes were relocated on the basis of an algorithm proposed in this study. Parameterization of the velocity structure is realized with a set of nodes distributed in the study volume according to the ray density. 120 nodes located at four depth levels were used to obtain the resulting P- and S-wave velocity structures. As a result, it is found that P- and S-wave velocity anomalies of the Rangnim Massif at depth of 8 km are high and low, respectively, whereas those of the Pyongnam Basin are low up to 24 km. It indicates that the Rangnim Massif contains Archean-early Lower Proterozoic Massif foldings with many faults and fractures which may be saturated with underground water and/or hot springs. On the other hand, the Pyongyang-Sariwon in the Pyongnam Basin is an intraplatform depression which was filled with sediments for the motion of the Upper Proterozoic, Silurian and Upper Paleozoic, and Lower Mesozoic origin. In particular, the high P- and S-wave velocity anomalies are observed at depth of 8, 16, and 24 km beneath Mt. Backdu, indicating that they may be the shallow conduits of the solidified magma bodies, while the low P-and S-wave velocity anomalies at depth of 38 km must be related with the magma chamber of low velocity bodies with partial melting. We also found the Moho discontinuities beneath the Origin Basin including Sari won to be about 55 km deep, whereas those of Mt. Backdu is found to be about 38 km. The high ratio of P-wave velocity/S-wave velocity at Moho suggests that there must be a partial melting body near the boundary of the crust and mantle. Consequently we may well consider Mt. Backdu as a dormant volcano which is holding the intermediate magma chamber near the Moho discontinuity. This study also brought interesting and important findings that there exist some materials with very high P- and S-wave velocity annomoalies at depth of about 40 km near Mt. Myohyang area at the edge of the Rangnim Massif shield.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.668-676
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• 2018

Most reservoirs in Korea have a low water depth and are small in size. Water pollution of the reservoir is serious because of the organic matter flowing from livestock wastewater, domestic sewage, and farmland. In this study, an attempt was made to improve the water purification effect by replacing the secondary dam installed in the depression area of the agricultural reservoir with the riprap dam. To evaluate the long-term performance, a riprap dam was installed in a reservoir in Gyeonggi province and water purification effect for 36 months was measured. The field test results showed that COD was 14.6%, SS 38.6%, T-N 9.5%, and T-P 11.2%. The concentrations in the influent water exhibited a significant change according to season, and the water purification effect increased with increasing concentration of influent water. The pollutant flowing into the lake from the depression area can be blocked effectively if the secondary riprap dam for water purification is installed in the agricultural reservoir.

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.515-521
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• 1997

To investigate the nature of the waste materials in the Nanjido Landfill, we have conducted multivariate statistical analysis of geophysical data set comprised of magnetic, gravity, LandSat TM thermal band and surface depression measurement data. Because these data sets show different responses to the depth, we have transformed the observed total field magnetic data and gravity data to the residual reduced-to-pole(RTP) magnetic anomalies and the three dimensional density anomalies, respectively, and utilized the informations about the upper shallow part of the landfills only in the following process. For the statistical analysis at the points of depression measurement, the magnetic, density and LandSat data values at these points are determined by interpolation process. Since the multivarite statistical analysis technique utilizes a clustering algorithm for classification of data set and we have measured the dissimilarity between objects by using Euclidean distance, standardization was applied prior to distance calculation in order to eliminate any scaling effects due to different measurement unit of each data set. The hierarchial grouping technique was used to construct the dendrogram. The optimum number of statistical groups(clusters), which are classified on the basis of geophysical and geotechnical characteristics, appeared to be six on the resulting dendrogram. The result of this study suggests that the dimension and nature of the multicomponent waste landfills can be identified by application of the multivarite statistical analysis technique to integrated geophysical data sets.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.95-106
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• 2019

This study examines how mental health promotion programs based on positive psychology brings changes in pleasant life, engaged life and meaningful life. This research considers 15 programs featuring 178 students during one semester. Pre-and-post examination of psychological well-being, depression and optimism were conducted to identify changes before and after the program. 56 students (32%) showed positive changes in all 3 factors. 15 students among them were selected for an in-depth interview for a qualitative case study. As a result of the quantitative study, a mental health promotion program based on positive psychology showed statistically significant positive changes in the pre-and-post examinations of psychological well-being, depression and optimism. Mental health promotion programs based on positive psychology showed positive changes in mental, cognitive and behavior perspectives in the fields of pleasant life, engaged life and meaningful life of college students. Specifically, positive psychology and thinking programs influenced students to become more enthusiastic and active in pursuing a pleasant life. Secondly, positive psychology intervention concerning engaged life brought a recognition of higher 'self-acceptance'. Thirdly, each individual spent more time and effort to experience more satisfaction and accomplishments. Lastly, subjects showed greater optimism after the program. Through the searching gratitude program, study subjects expanded their appreciation of their relationships with others.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.2
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• pp.97-105
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• 2017

Purpose: The purpose of this study was comparing the efficacy of passive irrigation (PI) and passive ultrasonic irrigation (PUI) for ability to remove debriment of canals. Materials and Methods: Mandibular premolars were decoronated and standardized to 16 mm length. After root canal enlargement and half separating longitudinally, standardized groove of 4 mm length, 0.2 mm width and 0.5 mm depth were formed on the dentin wall of one half. Three depressions in the canal wall of the opposite half, 0.3 mm in diameter and 0.5 mm in depth, were formed. After each groove and depression was filled with dentin debris, two sections of each half were reassembled using impression putty material. In group 1 the canals were irrigated with 2.5% NaOCl by PI. In group 2 the canals were irrigated with 2.5% NaOCl by PUI. Before and after root canal irrigation, the root canal wall of the section was taken with a microscope and a digital camera as images. The amount of dentin debris remaining in grooves and depressions was assessed using a scoring system. Results: There was no significant difference between PI and PUI except for the middle 1/3 of the root canal (P = 0.004). Conclusion: At the middle 1/3 of the root canal, PUI removed more dentine debris than PI. But the removal efficiency of dentin debris is not significantly different between the PUI and PI at the apical area of root canal in mandibular premolars.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.160-168
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• 2019

This study was conducted in order to suggest directions for nursing intervention and education to prevent problem drinking of adolescents. We examine the influences of mental health characteristics of adolescents on problem drinking. For the research method, this study conducts secondary analysis using raw data from the 13th (2017) Youth Risk Behavior Web-based Survey. A total of 9,597 cases, excluding adolescents without drinking experience, were used for the final analysis. For the data analysis, the SPSS Win 23.0 program was used, and frequency analysis, ${\chi}^2$-test, and logistic regression analysis were conducted. Research results found general characteristics, school, school record, living type, father's education, and economic state were influencing factors on problem drinking. Regarding characteristics of mental health, depression (95% CI:1.578~1.930, p<.001), subjective happiness (95% CI:1.039~1.491, p=.002), suicidal ideation (95% CI:1.110~1.426, p<.001), and sufficiency of sleep (95% CI:1.085~1.399, p=.001) were primary factors affecting adolescents' problem drinking. Therefore, when conducting education for preventing problem drinking or nursing intervention programs targeting adolescents, it is necessary to provide methods offering experts' in-depth consultation with the consideration of characteristics of mental health of participants. Future research should conduct qualitative studies through in-depth interviews for reviewing problem drinking and identifying characteristics of adolescents. This study provides guidelines for nurses working with problem drinking adolescents in clinical settings and communities.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.520-531
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• 2019

The purpose of this study is to understand in depth the experiences regarding the healing of stress that takes place in the process of the job performance of fire fighting officers. For this, by having seven incumbent fire fighting officers as the subjects of the research, the individual in-depth interviews had been conducted. As a result of analyzing their experiences based on the phenomenological research method of Colaizzi, the 17 topic bundles, 5 subcategories, and 3 categories were derived. Regarding the results of the research, firstly, it appeared that the stress resulting from the job performance in the diverse processes of solving the petitions experienced as the obsessive anxiety, feeling of depression and sleep disorder, etc. Secondly, it had appeared that fire fighting officers show the strong feeling of pride and sense of calling regarding the job performance, but their dread regarding the life after the retirement was high. Thirdly, it appeared that such stress were offset and healed through the positive experiences, including the professional vocation, companionship and support by the family, etc. Because the high job stress gets developed into the continuous and complex physical problems and the emotional and psychological problems, it shows that there is a limitation to the healing with only the professional calling, companionship and support by the family. As such, for the healing of stress that takes place in the job performance by fire fighting officers and not just for the environmental improvements that are related with the job, but for the psychological and emotional support, this research arrived at the point of the suggestion that the operations of the complex and systematized supporting programs, including the strengthening of vocation and companionship, emotional support by the family etc., must be carried out.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.3
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• pp.253-263
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• 2022

A buccal pit is a prominent point-like depression that appears at the cervical end of the mandibular molar developmental grooves. A defective buccal pit can be defined as a buccal pit in which the continuity of the dentinoenamel junction is broken and the pit extends to the dentinal level. This study aimed to determine the frequency of buccal pits and defective buccal pits in un-erupted mandibular first and second molars using cone-beam computed tomography (CBCT). The analysis was performed on CBCT images taken from 417 Korean children and adolescents who visited the Department of Pediatric Dentistry, Yonsei University Dental Hospital between 2004 and 2020. Based on cross-sectional views of CBCT images, buccal pits were categorized into 4 classes according to the depth of the pits. The expression rate of the buccal pits was 29.1%. The prevalence of defective buccal pits was 7.9%. The buccal pits tended to develop bilaterally. To date, this is the most comprehensive study on the frequency of buccal pits with the largest sample size. This was the first attempt worldwide to analyze the depth of the buccal pit using CBCT images and to define a defective buccal pit worldwide.

• Journal of Convergence for Information Technology
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• v.12 no.3
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• pp.171-177
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• 2022

The retirement of the Korean baby boomer generation has become a major factor in an aging society as a large proportion of the population has moved from the middle-aged to the elderly. In addition, after being busy working at a structured workplace for over 30 years, after retirement, they could not adapt to the unstructured environment, causing depression and leading to social problems such as the risk of suicide. research was needed. This study uses photovoice to in-depth research on the research question of how retirees' perception of death preparation, who wants to live a life prepared until death, is used. This is the purpose of this study. The study participants were 7 baby boomer retirees, the data were collected for 2 months, and the perception derived as a result of analyzing the photos, explanations, and in-depth interviews taken by the subject analysis method was used to prepare It was a necessity for education. In the discussion of this study, it is urgent to develop a death preparation education program that can help the baby boomer retirees, and I would like to suggest that the cooperation of local organizations in charge of the program is necessary. This study is meaningful in that it presents basic data in preparing social welfare policy measures for the elderly after retirement through the awareness of death preparations of baby boomer retirees.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.132-146
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• 2016

The purpose of this study was to develop a Korean version of the acceptance attitude scale and was to verify the reliability and validity of this scale. Study 1 was developed to acceptance attitude scale. First, we extracted the preliminary questions through literature research and previous studies. And the resulting data of to the open-ended questions and in-depth interviews with 324 college students were selected 24 preliminary questions using the content analysis method. Then through a survey of 355 college students conducted a reliability analysis and exploratory factor analysis, confirmatory factor analysis of the preliminary questions. As a result, 12 item with two sub-factors(externally acceptance, interally acceptance) was extracted. Study 2 was for the validation of the new acceptance attitude scale was conducted online surveys of 328 adults. Conducted a correlation analysis between new acceptance attitude scale and self-esteem, psychological wellbeing, depression, anxiety, fear of negative evaluation were verified for convergent validity. Finally, importance and limitation of this scale development and suggestions for future research are discussed.