• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.545-550
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• 2019

The frequency of natural disasters and the scale of damage are increasing due to the abnormal weather phenomenon occurring all over the world. As a result, as the hydrological aspect of the urban watershed changes, the increase in impervious area leads to serious domestic flood damage due to increased rainfall. In order to minimize the damage of life and property, domestic flooding prediction system is needed. In this study, we developed a flood nomogram capable of predicting flooding only by rainfall intensity and duration. This study suggests a method to set the internal water immersion alarm criterion by analyzing the characteristics of the flooding damage in the flooded area in the metropolitan area where flooding is highly possible and the risk of flooding is high. In addition, based on the manhole and the pipe, the water level was set as follows under the four conditions. 1) When manhole overflows, 2) when manhole is full, 3) when 70% of the pipe is reached, and 4) when 60% of the pipe is reached. Therefore, it can be used as a criterion and a predictive measure to cope with the pre-preparation before the flooding starts, through the rainfall that causes the flooding and the flooding damage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.614-626
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• 2018

This study was conducted to review the literature and examine the factors related to problem behaviors among students of multicultural families in Korea. A systematic review of the literature was conducted using domestic documents retrieved through July 4, 2018 based on online searches of domestic databases (the Research Information Sharing Service, Korean Studies Information Service System and the National Diet Library). A total of 2,084 studies were searched, and 21 studies were used for analysis. The factors related to problem behaviors were related to individual factors (gender, school record, self-esteem, etc.), family factors (family type, parent support, mothers' enculturation stress, etc.) and environmental factors (friend support, teacher support, social support). The variables measured the problem behaviors among students of multicultural families were school life adjustment (10), psychological, social adjustment or maladjustment (4), and emotional problem behavior (3). Overall, the results indicate that social and policy efforts are needed to improve individual, family, and environmental factors based on more specific and consistent theoretical definitions related to problem behaviors among students of multicultural families in Korea.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.2
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• pp.115-123
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• 2018

Various types of robots running on power transmission lines have been developed for the purpose of line patrol monitoring. They usually have complex mechanism to run and avoid obstacles on the power line, but nevertheless did not show satisfactory performance for going over the obstacles. Moreover, they were so heavy that they could not be easily installed on the lines. To compensate these problems, flying robots have been developed and recently, multi-copter drones with flight stability have been used in the electric power industry. The drones could be remotely controlled by human operators to monitor power distribution lines. In the case of transmission line patrol, however, transmission towers are huge and their spans are very long, and thus, it is very difficult for the pilot to control the patrol drones with the naked eye from a long distance away. This means that the risk of a drone crash onto electric power facilities always resides. In addition, there exists another danger of electromagnetic interference with the drones on autopilot waypoint tracking under ultra-high voltage environments. This paper presents a patrol monitoring plan of autopilot drones for power transmission lines and its field tests. First, the magnetic field effect on an autopilot patrol drone is investigated. Then, how to build the flight path to avoid the magnetic interference is proposed and our autopilot drone system is introduced. Finally, the effectiveness of the proposed patrol plan is confirmed through its field test results in the 154 kV, 345 kV and 765 kV transmission lines in Chungcheongnam-do.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.362-369
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• 2019

This descriptive study investigated depression among 4,904 elderly people aged 60 to 90 years using the Korean Retirement and Income Study. The depressive group and non-depressive group were classified by the depression self-diagnostic scale, CES-D. The effects of general characteristics, disability, disability type, IADL, and social support on depression were examined. A t-test, chi-squared test, and logistic regression analysis were used to identify risk factors affecting depression. The average age of the depressive group was 75.10 years, which was higher than the average age of the non-depressive group (73.44 years), indicating that depression increased with age. Elderly who were female, elderly with no spouse, elderly with lower educational attainment and with a lower household income were in the depressed group. The score to perform IADL of disabled persons was higher than that of non-disabled persons, and the social support was lower. Logistic regression analysis performed to determine the risk factors affecting depression revealed that it was affected by disability and type of disability. Although this study has some limitations, the results presented herein can be used as a basis for understanding elderly with disabilities and developing future healthcare programs for them.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.1
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• pp.107-120
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• 2019

The decommissioning of one nuclear power plant in a multi-unit nuclear power plant (multi-unit NPP) site may pose radiation exposure risk to decommissioning workers. Thus, it is essentially required to evaluate the exposure dose of decommissioning workers of operating multi-unit NPPs nearby. The ENDOS program is a dose evaluation code developed by the Korea Atomic Energy Research Institute (KAERI). As two sub-programs of ENDOS, ENDOS-ATM to anticipate atmospheric transport and ENDOS-G to calculate exposure dose by gaseous radioactive effluents are used in this study. As a result, the annual maximum individual dose for decommissioning workers is estimated to be $2.31{\times}10^{-3}mSv{\cdot}y^{-1}$, which is insignificant compared with the effective dose limit of $1mSv{\cdot}y^{-1}$ for the public. Although it is revealed that the exposure dose of operating multi-unit NPPs does not result in a significant impact on decommissioning workers, closer examination of the effect of additional exposure due to actual demolition work is required. The calculation method of this study is expected to be utilized in the future for planned decommissioning projects in Korea. Because domestic NPPs are located in multi-unit sites, similar situations may occur.

• The Southeast Asian review
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• v.24 no.2
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• pp.167-206
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• 2014

메콩 경제권(GMS)의 다양한 개발 현장 속에서 고무 나무로부터 채취하는 라텍스는 캄보디아, 라오스를 포함한 인도 차이나 반도 국가들 사이에서 주요 농업 활동으로 주목 받고 있다. 그러나 캄보디아와 라오스의 대형 플랜테이션은 여러 부정적인 결과들을 낳고 있다. 토지 점유, 계약 농업을 통한 착취 등으로 인해 역설적으로 농촌의 빈곤은 증가하고 있고 해외 투자자에 대한 재정적, 기술적 의존이 심화되고 환경 파괴가 일어나고 있다. 이러한 점들로 인해 소규모 자작농들에 주목할 필요가 있다. 고무 자작농은 고용을 창출하며 토지 점유를 방지한다. 본 연구는 캄보디아와 라오스의 소규모 고무 자작농들의 생계를 비교하며 고무 호황으로 어떠한 이득을 얻고 어떠한 형태로 생계를 개선할 수 있는지를 연구한다. 본 연구는 캄보디아의 Tboung Khmum 구역과 Somsanouk 마을의 사례 연구를 바탕으로 하였다. 실증적인 분석은 세 가지의 이론적 틀을 바탕으로 하였다. 미시-생계 연구, 글로벌 가치사슬 그리고 GMS에 대한 연구들이다. 실증 분석의 초점은 생계의 변화상과 결과(고용 창출과 빈곤 탈출)이다. 전체적으로 소규모 고무 자작농은 전망이 밝았으나 앞서 언급 된 문제점들로 인해 농촌 문제를 모두 해결할 수 있는 수단은 아니다. 중요한 유사성은 소규모 고무 자작농의 사회경제적 공헌이다. 연구 지역 두 곳에서 자작농들은 고무 농사는 생계를 개선하는 데에 좋은 수단이라고 답하였다. 그럼에도 불구하고 낮은 교육 수준은 그들의 생계 전략을 불안정하게 하고 있다. 양쪽 지역에서 응답자들은 다른 주민을 따라 고무 농사를 시작했다고 대답했으며 경제, 환경적인 위험에 대해 충분히 인지하고 있지 못하였다. 이와 관련한 다른 유사점으로 소규모 자작농들을 지원할 수 있는 정부의 개입이 없었다는 것이다. 자금 조달은 고무 농사의 심각한 애로 사항 중 하나였다. 명확한 차이점으로 Tboung Khmum의 자작농들은 중개 상인에게 계약 관계를 맺지 않고 라텍스를 판매했으며 Somsanouk의 경우에는 고무 가격이 국제 시장의 영향을 받음에도 가장 높은 가격을 제시하는 상인에게 농민 전체가 같이 판매를 하였다. 이러한 현상은 GMS 내에서 이루어지고 있는 근대적인 경제 현상 에 농촌 공동체들이 다양하게 연결 되고 있음을 재확인한다. 게다가 Somsanouk 마을에서는 사이짓기를 하는 경우가 없었다. 이는 투자자들이 생산량을 극대화하기 위해 자작농들에게 사이짓기를 장려하지 않았기 때문이다. Tboung Khmum 마을의 경우 고무와 더불어 고무 이전의 주요 작물이던 카사바를 같이 재배했다. 요약하면, 자작농에 의한 소규모 고무농업은 (비록 농촌의 모든 어려움을 해결할 수는 없지만) 토지점유 등 부정적 현상이 나타나는 대규모 플렌테이션에 비해 유의미한 일자리를 창출하는 등 미래를 위한 보다 나은 대안이 될 수 있다. 농촌 생활의 질을 개선하기 위해서는 7년 간의 고무 생육기간 동안 농가가 감수해야 하는 사회-경제적 불안정성을 해결하고 대안적 소득원을 마련할 필요가 있다

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.88-96
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• 2021

When oil tankers, large passenger ships and cargo ships sink under the sea owing to various maritime accidents, the residual cargo oil or fuel oil in the such vessels could pose direct risk to factor for the marine environment and it require safe and rapid removal. Although domestic and foreign salvage companies are adopting various recovery methods and technologies with customizations according to each site during recovery operations studies on reasonable assessment modules for the operation process are relatively insufficient. In this study, the data from trapped-oil recovery operations performed at different site conditions were collected and analyzed in order to designed an operation assessment module, define the operational process steps in terms of preparation, implementation and completion, and derive key factors for each detailed process. Subsequently, the module was designed in such a way as to construct performance indicators to assess these key factors. In order to exclude subjective opinions from the assessment as much as possible, the assessment each item was constructed with indicators based on data that could be evaluated quantitatively and its usefulness was verified by applying the module to the trapped-oil recovery operation cases. We expect this the method and the technology assessment module for the trapped-oil recovery operation on sunken vessels will help to verify the adequacy of the trapped-oil recovery such operation before or after. Furthermore, it is expected that the continuous accumulation of assessment data and feedback from past or future operation cases will contribute toward enhancing the overall safety, efficiency and field applicability of trapped-oil recovery operation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.10
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• pp.1331-1340
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• 2020

Object detection in maritime means that the captain detects floating objects that has a risk of colliding with the ship using the computer automatically and as accurately as human eyes. In conventional ships, the presence and distance of objects are determined through radar waves. However, it cannot identify the shape and type. In contrast, with the development of AI, cameras help accurately identify obstacles on the sea route with excellent performance in detecting or recognizing objects. The computer must calculate high-volume pixels to analyze digital images. However, the CPU is specialized for sequential processing; the processing speed is very slow, and smooth service support or security is not guaranteed. Accordingly, this study developed maritime object detection software and implemented it with FPGA to accelerate the processing of large-scale computations. Additionally, the system implementation was improved through embedded boards and FPGA interface, achieving 30 times faster performance than the existing algorithm and a three-times faster entire system.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.561-568
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• 2020

Wave measurements using X-band radar have many advantages compared to other wave gauges including wave-rider buoy, P-u-v gauge and Acoustic Doppler Current Profiler (ADCP), etc.. For example, radar system has no risk of loss/damage in bad weather conditions, low maintenance cost, and provides spatial distribution of waves from deep to shallow water. This paper presents new methods for estimating significant wave heights of X-band marine radar images using Artificial Neural Network (ANN). We compared the time series of estimated significant wave heights (Hs) using various estimation methods, such as signal-to-noise ratio (${\sqrt{SNR}}$), both and ${\sqrt{SNR}}$ the peak period (TP), and ANN with 3 parameters (${\sqrt{SNR}}$, TP, and Rval > k). The estimated significant wave heights of the X-band images were compared with wave measurement using ADCP(AWC: Acoustic Wave and Current Profiler) at Hujeong Beach, Uljin, Korea. Estimation of Hs using ANN with 3 parameters (${\sqrt{SNR}}$, TP, and Rval > k) yields best result.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.547-557
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• 2020

This study examined the level of depression according to the characteristics of school and family life of female high school students. In particular, this study attempted to identify the relationship between academic stress and the depression levels. The survey conducted a self-administered questionnaire from 438 students at D city in August, 2019. As a result, the distribution of the depression levels among the study subjects was 78.8 % for 「normal」 and 21.2 % for 「depression」, and the distribution of depression was significantly higher in groups with higher academic stress. The academic stress and depression levels showed significant positive correlations. In logistic regression analysis, the risk ratio of 「depression」was significantly higher in groups with higher academic stress than in groups with lower academic stress. According to multiple regression analysis, the factors affecting the level of depression were chosen as significant variables, such as academic achievement, relationship with school fellow, satisfaction with school life, test stress, study stress, and career stress. The above findings suggest that the level of depression in female high school students was related to academic stress and many other variables of school and family life characteristics.