• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.8-12
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• 2015

Non-esterified bio-diesel fuel saves cost by no esterified process and its performance was more similar to diesel oil than esterified bio-diesel fuel when the fuel blended 95% diesel oil and 5% it was used on diesel engine with electronic control system. A performance optimization is necessary for application of non-esterified bio-diesel fuel blended with diesel oil 95% on the latest diesel engine. In this study, test using fractional factorial design was accomplished at 25% and 50% partial load in order to evaluate influence of controllable 6 factors on responses such as specific fuel consumption, nitrogen oxides and coefficiency of variation of indicated mean effective pressure as basic experiment for performance optimization of this fuel. It is cleared that the injection timing and common rail pressure of 6 factors are mainly effective and its effect level is different according to load.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.125-125
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• 2016

남강 권역은 5개의 단위유역으로 구성되어 있으며, 남강A, 남강B, 남강C, 남강D와 남강E로 명명되고 1단계 수질오염총량관리제도 시행 이후 유역 내 개발 등으로 인한 오염원이 증가하고 장기간 퇴적된 저니층으로부터 오염물질이 용출되는 등 수질의 자정능력보다 더 많은 오염물질이 수체내로 유입됨으로써 수질이 악화되자 수량확보 뿐만 아니라 남강의 수질관리에 대해서 관심을 가지기 시작하였다(GNDI, 2010). 남강 하류수계는 하상구배가 매우 완만하며 유속이 느리다. 따라서 물의 체류시간이 호수와 비슷한 양상을 보이고 있다. 더욱이 남강 하류수계는 주변의 도시와 농경지로부터 물의 소모량이 크기 때문에 하류수계의 물의 흐름이 더욱 완만해지고 이로 인하여 수질 악화가 가속화되고 수역의 영양단계가 점점 증가하는 부영양화현상이 발생되고 있다. 남강하류수계와 같이 부영양화 된 수계내의 미처리 된 영양염을 이용한 식물플랑크톤의 생산에 의해 자생BOD가 공급된다. 따라서 남강댐 하류지역과 같은 수리 수문학적 특징을 가진 유역은 수질관리를 위해서 특정 수역에 유입 BOD와 자생 BOD가 어느 정도 기여하는가를 정량적으로 파악한 후, 기여도에 따라 오염원인 물질을 줄이기 위한 수질관리 방안이 설정되어야 한다. 본 연구에서는 남강유역의 오염원의 기여율 분석을 위해 하천수질모델인 QUALKO2를 사용하였으며, 점오염원 뿐만 아니라 수질에 상당한 영향을 끼치는 비점오염원의 영향을 통합적으로 고려하기 위하여 유역 모델인 SWAT과의 연계방안을 제시하였다. 또한 모델의 연계 적용을 통해 산정된 내부오염원과 내부오염원의 기여율과 수질측정결과를 활용하여 분석한 기여도와의 비교를 수행하여 신뢰성을 확보하였다.

• Land and Housing Review
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• v.14 no.2
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• pp.1-17
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• 2023

In Korea, the population size of the elderly is rapidly increasing, and housing for them is emerging as an important issue. In particular, Aging in Place (AIP) has steadily been presented as a direction of welfare for the elderly. This study empirically examines the effect of the interactions of the elderly with their children on residential mobility for older Koreans. To do so, this study employed random effect logistic regression models with the dataset of the 2008-2020 Korean Longitudinal Study of Aging. The findings are as follows. First, it was found that the interaction with their children increased the probability of residential mobility for older Koreans in both metropolitan areas and non-metropolitan areas. Second, as age increased, the interaction with their children tended to further promote residential mobility for older Koreans, but such effects varied depending on related variables. Third, it was confirmed that the possibility of further promoting residential mobility for older Koreans increased through the interaction effects of the variables associated with the interaction with their children. This study suggests policy implications for the residential mobility of older Koreans, i.e., whether the interactions with their children improve independent residential environments by enhancing housing stability, in terms of AIP.

• Land and Housing Review
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• v.15 no.1
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• pp.135-146
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• 2024

This study predicts the means sharing ratio of the urban air transportation (UAM) when the VertiHub of the UAM in the southern western part is built at Songjeong Station in Gwanju. Based on Monte Carlo simulation of the utility function and means selection logit model for each means of transportation, our findings indicate an average mode share of 0.95%, with a variability range from 0.07% to 4.7%. Moreover, 95% of the simulation outcomes fall below a 2.02% mode share. Sensitivity analysis, conducted via Tornado Plot, highlights that the mode share is principally influenced by factors such as the unit fare, cost parameter, basic fare, and the time required for takeoff and landing. Notably, a negative correlation exists for unit fare, basic fare, and takeoff and landing time, suggesting the necessity of setting an appropriate level of fair to enhance UAM utilization.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.2147-2156
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• 2013

This study aims to analyze the evaluation of the residential environment on the permanent rental housing in Busan. The Permanent Rental Housing policy is one of the special measures which contribute to getting the low-income urban dwellers settled in places of their own. Unfortunately the government has focused on expanding the quantity of housing even though housing doesn't mean just a physical object but the foundation of life. So the occupants who answered the survey lived in the permanent rental housing which were constructed by Busan Metropolitan Corporation. The purpose of the study is to give suggestions which can make up for dissatisfaction and apply preference of occupants based on the results of the research. The result of this study is in following; there were few significant managerial variables determinants of residential satisfaction. And significant variables are; position of rooms and bathroom facilities in internal building characteristics, color of apartment and playground in exterior building characteristics, commuting distance and viewshaft in locational characteristics. Therefore, the government needs to use cutting edge housing technologies aimed at improvement of residential environment and achievement of affordable expense simultaneously.

• 한국노년학
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• v.36 no.3
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• pp.581-594
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• 2016

This study aims to observe the effect of age friendliness of cities on life satisfaction and to suggest ways to improve quality of life of older people. The secondary data sets were used in this study, which were '2014 Survey of Living Conditions and Welfare Needs of Korean Older People.' It's a nationwide data collected by the Korean Institute of Health and Social Affairs. A multilevel analysis model was used to analyze the data because the level of age friendliness has a hierarchical data structure. Results showed as follows: First, life satisfaction of older adults is affected by the level of age-friendliness of cities in which they live. Second, on the personal level, older people showed low life satisfaction when they are more older and have more chronic diseases and more depressed. On the contrary, life satisfaction of older adults increased when they have higher education and income. Third, on the city level, older people showed higher life satisfaction when they live in high employment rate area and participation rate of lifelong education. Cautions should be placed when interpret the result because the variables that represent the characteristics of age friendless of cities were constituted arbitrary. Based on the results, suggestions for improving the city environment age-friendly and implications for social welfare practice were provided.

• Land and Housing Review
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• v.13 no.1
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• pp.67-84
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• 2022

This study aims to investigate the value of greenbelts exploring how they can be linked with green infrastructure networks. This research interprets the results of geographical information system (GIS) analysis differently from a conventional approach. The findings of the research are four-fold based on the analysis of the Daejeon Metropolitan Area. First, the most controversial greenbelts are laid on Yuseong-gu because the relaxation of the greenbelts for new housing development has caused outstanding issues since the early 2000s. Decisions on further relaxation or restoration of the greenbelts, which will provide a new direction for the establishment of green infrastructure networks, should be made through accurate environmental assessments. Second, the connected north-south corridors of large cities will affect the greenbelts not only in Daejeon, but also in the entire Chungcheong Provinces, and surrounding local municipalities, which should be considered for the revision of the greenbelt policy. Third, it is expected to experience growing development pressures towards neighboring municipalities due to the ongoing strict greenbelt policy. Among them, the most likely areas are Sejong City to the north and Nonsan to the south, requiring policy measures. Fourth, the value of green infrastructure should be added to current evaluation criteria rather than a binary approach - relaxing or preserving the greenbelts - to be holistically integrated with a metropolitan plan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2680-2689
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• 2012

This study was aimed at finding out the relationship between the level of depression and the recognition and attitude of suicide and the study was conducted by a structured and self-filling questionnaire survey for 1,114 urban area students and 968 rural area students (totaled 2,082) in K city in the central districts of the country from July 1, 2009 to July 31, 2009. The result of the study showed that the more serious the level of depression, the higher the recognition and level of attitude for suicide was. Suicide attitude had a meaningful relationship with the degree of suicide recognition and the level of depression and the level of suicide recognition was closely connected with the level of depression. The result of the analysis of Hierarchial multiple regression showed the meaningfully related factors that affect the level of depression were sex, major, grade, school life satisfaction, fellowship with schoolmates, departing from girl or boyfriends, the lowest bracket of living standard, subjective health, smoking, financial status of household, a quarrel with parents and attitude of suicide. In particular, variables that are related to the condition of family life have high relationship with the level of depression.

• 한국노년학
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• v.38 no.3
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• pp.593-605
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• 2018

This study examines factors that influence older drivers to consider stopping driving in advance and whose advice plays an important role in the driving cessation decision. Data came from a nationally representative cross-sectional survey of community-dwelling older adults (N=2,076). About two thirds reported that they have considered stopping driving (62.8%) and they preferred to decide by themselves (66.0%). Logistic regression results showed that women and residents in urban areas were twice as likely to consider voluntary driving cessation compared to their counterparts. Each one year increase in age contributed to the probability that respondents would consider driving cessation by five percent. Those with greater difficulties in ADLs due to chronic illnesses were also more likely to consider driving cessation. No sociodemographic and health factors were related to whether older drivers preferred to decide by themselves or listen to others. These results imply that policies to promote self-motivation to stop driving among older drivers would be effective. Furthermore, they suggest it could be important to help older drivers plan their driving cessation in advance while still at a young-old age, and that more attention needs to be paid to men and those living in rural areas among older drivers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.1
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• pp.85-91
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• 2021

In contrast to standard train tracks, tramlines are often set along public roads, with trams running among pedestrians and other vehicles. In some cities and towns, trams and buses share the same routes and stations. Under the current investment appraisal system, trams are classified into light rail when predicting traffic demand and calculating benefits, but in the case of non-capital areas, it is notable that the origin-destination and transit lines of buses are not provided in the Korea Transport Database distribution data. Due to this problem, it is difficult to reflect proper mode changing behaviors between route buses and trams. This study examines the impact on tramlines of bus routes that are not currently considered in non-capital areas. Following an analysis of the effect of tram projects according to whether bus routes are considered or not, an improvement in methodology is proposed. Through this study, it is expected that the investment appraisal system for the planning of new tramlines will be improved in the future.