• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.2
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• pp.98-105
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• 2013

The purpose of this study was to investigate the mesiodistal widths at the cervical level of primary second molars in Korean children, and to compare them with commercial rubber dam clamps commonly used in pediatric dentistry. Dental casts of 115 primary and mixed dentition children were studied. Cervical mesiodistal width (C-MD) was measured at the clinical cervical level of each primary second molar from buccal and lingual sides using a digital caliper (Absolute, Mitutoyo, Kawasaki, Japan). The data were compared with mesiodistal widths of rubber dam clamps #203/204, #10/11, and #205 (Dentech, Japan). C-MDs of primary mandibular second molars were larger than those of primary maxillary second molars, and C-MDs at buccal sides were larger than those of lingual sides. All C-MDs showed statistically significant discrepancies to corresponding widths on clamps (p < 0.05). However the amount of discrepancy was mild in maxillary teeth, while up to 1 mm of discrepancy was shown in mandibular teeth. In conclusion, C-MDs measured in this study imply a relatively fair fit of #10/#11 or #203/#204 clamps on primary maxillary second molars, while suggesting our need for a better clamp with proper size for primary mandibular second molars.

• Journal of the Korean GEO-environmental Society
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• v.19 no.11
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• pp.23-30
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• 2018

According to recent ground collapse occurrence, ground subsidence is increasing every year in downtown area, which is a social problem. The purpose of this study is to investigate the relationship between ground water level lowering and ground collapse through laboratory model experiments. After mixing 1:1 granite weathered soil with sand, sandy soil was formed as a relative density of 30%, 50%, and 80%. And then the changes of soil discharge with change of groundwater level were compared. The physical property of material of which particle distribution were well graded with maximu dry unit weight of $1.94kg/cm^3$ and internal friction angle of 37degrees. Ground water levels were measured at 10 cm, 20 cm, and 30 cm from the bottom. As a result, the experiment shows that the higher the groundwater level works the higher the discharge velocity and the magnitude of underground cavity also increases with elapsed time. Finally, the cumulative quantity of soil discharge occurred up to 30 kg at the elapsed time, 35 minutes. It was also confirmed that the range of ground collapse increased due to soil discharge with ground water level lowering.

• Journal of Science Education
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• v.44 no.2
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• pp.240-258
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• 2020

The advances in science technology brought about a new form of learning called flipped-learning: a combination of on-line and off-line learning. A flipped learning is a form of blended learning which has become quite popular, nowadays, in the field of education. Despite the emphasis on the importance of medical humanities in medical education program, there are no effective teaching and learning models to realize the purpose of medical humanities education. This study explores the possibility of flipped-learning to apply medical humanities classes. The class was designed based on the ADDIE model consisting of five stages, analysis - design - development - execution - evaluation. In order to do 'flipped-learning,' the instructor reconstructs the purpose of medical humanities education, instructional purpose and content, and analyzed learner. The contents of the medical humanities class were structured considering the purpose of the introduction to the medical humanities in the medical education program and the competencies that medical personnel should have in the developed health care environment. The instructor produces a video of the lecture and makes it possible to use LMS (Learning Management System) before and after classes, and conducts discussion activities so that learner-learner and learner-teacher interaction could actively occur during the class. The result of applying medical humanities lesson as flipped learning is as follows: First, it can realize the essence of medical humanities education. Second, it contributes to strengthening the competencies of health care provider. Third, flip learning can be used as a new teaching strategy for medical humanities education. The result of this study is expected to suggest new ways of introduction to teaching method in the traditional medical humanities class and contribute to the practice of designing and doing flipped learning of medical humanities class in the future.

• Fire Science and Engineering
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• v.20 no.4 s.64
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• pp.1-12
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• 2006

In this study, CFD computer simulations by FDS are carried out in order to confirm the performance of the combined operation of both sprinkler system and smoke curtain of 0.54 m depth installed for cooling and blocking the smoke which propagates beneath the sloped ceiling of a stairway corridor of which dimensions are 17.92 m long, 4.00 m wide, and 6.12 m high. It is shown that the response time of sprinklers decreases with fire size and it increases more about 1.1 second in case without smoke curtain than in case with smoke curtain, that the time of smoke transport from the fire source to the stairway outlet decreases considerably with fire size, and that the delay effect of smoke transport is not related to the sprinkler system, whether it is operated or not. This study shows that the combined operation of both sprinkler system and smoke curtain is very effective in smoke cooling, but it is a little for effect on smoke blockage. Although the hazard of skin burn due to radiative heat flux from hot smoke layer is decreased by spray cooling effect, the hazard of smoke suffocation and the weakening of visibility is increased by smoke downdrag and the turbulence of smoke-air mixing due to water spray. These conditions may result in preventing occupants from going out of the stairway during evacuation.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.640-647
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• 2017

The need for an efficient sampling technique to collect aquatic organisms has risen with the increase of interest in rice paddy fields, which have been recognized as important ecosystems supporting biodiversity. In the present study, a submerged funnel trap used with the assistance of attracting agents (fish meal and chemical light) was designed as an easy, objective and quantitative tool for collecting aquatic organisms in the rice paddy fields. The preference for collecting aquatic organisms as a means for attracting agents was analyzed using a generalized linear mixed model. Also, based on the data of previous research, we compared the community composition of the aquatic macroinvertebrates, which were collected using the quadrat method, and newly designed submerged funnel traps, by analyzing non-metric multidimensional scaling. The results showed that the catching efficiency of 18 of the total 65 taxa was affected by the attracting agents. 12 taxa including Pomacea canaliculata, Hippeutis cantori, Austropeplea ollula, Erpobdella lineata, Ostracoda spp. Branchinella kugenumaensis, Hydaticus grammicus, Rhantus pulverosus, Chironomidae spp., Rana nigromaculata, Cobitidae spp. etc., favored fish meal and 6 taxa including Ischnura asiatica, Coenagrionidae spp. Sternolophus rufipes etc., were attracted by chemical light. The submerged funnel trap used as a measurement tool for biodiversity was less applicable than the quadrat method; however, it was more effective for the selective collection of specific taxa. We expect that this newly designed trap can be a simple and quantitative method for collecting aquatic organisms, and could be used for long term and extensive surveys in rice paddy fields in the future.

• Journal of agriculture & life science
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• v.46 no.5
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• pp.57-63
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• 2012

The purpose of this study was to estimate genetic parameters for productive traits in Duroc breed. In this study, 40,657 records for productive traits and the pedigree data of 47,974 families were collected from 41 farms registered at the Korean Animal Improvement Association (KAIA) from 2004 to 2011. The REMLf90 program was used to analyze a multiple traits animal model with fixed effects of sex, contemporary group, parity and age at the end of the test as covariate and random effects of animal and residual error. The heritabilities of days to 90 kg (D90KG), average daily gain (ADG), backfat thickness (BF) and eye muscle areas (EMA) were estimated to be 0.334, 0.340, 0.335, and 0.200, respectively. The genetic correlation coefficients were -0.992 between D90KG and ADG, -0.142 between ADG and BF, -0.361 between ADG and EMA, and -0.243 between BF and EMA. Conversely, positive genetic correlations for D90KG with BF and EMA were 0.13 and 0.36, respectively.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.179-189
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• 2019

Korea's transportation paradigm is shifting from a vehicle-centered to a pedestrian-oriented society. Therefore, the interest in pedestrian safety and the improvement of pedestrian environment is also increasing. However, the level of traffic safety in Korea is still severe. It is needed to improve pedestrian safety and pedestrian environment. This study studied pedestrian-vehicle accident data provided by the Traffic Accident Analysis System(TAAS) for 2013-2015 to build a safe walking environment around school zones, and the relation between the school zones and pedestrian-vehicle traffic accidents were identified through the geographic information system(GIS) and spatial regression model. The main results are as follows. First, both road and public transportation factors are likely to increase pedestrian traffic accidents in school zones. Second, regarding land-use factors, residential, commercial, and industrial areas are found to increase pedestrian traffic crashes. On the other hand, mixed use is likely to play a role on the reduction of pedestrian traffic accidents. Finally, it has been shown that high development density also has a positive effect on pedestrian traffic accidents in school zones.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.398-398
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• 2018

OECD 발표에 의하면 물산업 관련 인프라 투자 전망은 전세계 GDP 대비 2010~2020년 약 1.01%에서 2020~2030년 약 1.03%로 확대될 전망으로 다른 통신, 전력, 철도 인프라 투자수요보다 많을 것으로 전망하고 있다(파이넨셜 뉴스, 2013.3.21.). 우리나라는 2005년 베트남 홍강종합개발사업을 시작으로 2015년 기준으로 세계 35개국에 진출하고 있다. 그러나 대부분의 물 산업 진출 대상 국가는 미계측 유역이 많고 지상에서 계측된 수문 자료가 부족한 실정이다. Namgung and Lee(2014)에 의하면 네팔의 수력발전소 건설에 관측된 강우량 자료가 없어 발전소 하류 10km 지점의 유하량 자료를 이용하여 자료의 정확도 검증을 대신하여 적용한 바 있다. 이와 같이 계측자료가 없거나 부족한 지역에 대하여 기상 위성을 이용하여 추정된 강수량 자료가 해당 지역의 강수 특성을 파악하는데 중요한 자료로 이용될 수 있다. 글로벌 위성 기반의 강수량 관측에 대한 역사는 1979년에 IR방법에 의해 위성으로부터 강우자료를 유도하는 개념이 도입된 이후 1987년 다중 채널의 마이크로파(MW) 복사계를 이용한 방법, 이후 두 IR과 MW를 혼합한 방법에서, 1997년 TRMM위성의 PR(Precpipitation Radar)의 레이더를 이용하는 방법, 그리고 2014년 GPM 핵심 위성(GPM Core Observatory)에 탑재된 Dual PR에 의한 방법으로 위성강수의 정확도를 매우 높여가고 있다. 본 연구는 KOICA 사업으로 진행중인 필리핀 메트로 마닐라 홍수조기경보 및 모니터링 체계 구축사업 중 파시그-마라키나강(Pasig-Marakina) 유역의 2012년 8월의 홍수사상에 대한 위성강우 및 글로벌 지형자료를 이용하여 홍수 유출량을 추정하는 것으로 목적으로 하고 있다. 유역내 6개 관측소의 일일 강우량 자료와 GPM IMERG 일강우량 자료 상관분석 결과 약 0.623, Bias는 -0.147, RMSE는 15.7정도로 분석되었다. 홍수량 분석은 2012년 8월 홍수가 발생한 시기인 2012년 8월 1일 00(UTC)부터 2012년 8월 16일 00(UTC)까지의 1시간 간격의 위성강우자료와 글로벌 지형자료를 이용하였고, 한국건설기술연구원의 MapWindow 기반 GRM 모형(mwGRM)을 이용하였다. 분석 결과 첨부홍수가 발생한 시기는 8월 7일 18:00(UTC)였고, 첨두 홍수량은 $4,073.9m^3/sec$로 분석되었다. 향후 수위-유량 관계식에 의해 정확도평가를 수행할 계획이다.

• Environmental and Resource Economics Review
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• v.28 no.2
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• pp.201-229
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• 2019

This paper estimates the effects of generation mix changes in the $7^{th}$ and $8^{th}$ Basic Plan for Long-term Power Supply and Demand from two aspects: economic efficiency through electricity prices and environmental performance through $CO_2$ and air pollutants(NOx, SOx, PM) emissions. Particularly, we examined additional generation mix conversion paths that take into account the trade-off between economic efficiency and environmental performance through scenario analysis. According to our results, the conversion from the $7^{th}$ plan to the $8^{th}$ plan should increase the electricity prices in the mid- and long-term, while reducing GHG and air pollutants emissions at the same time. The alternative generation mix that combines $7^{th}$ and $8^{th}$ plans shows that there exists a path to mitigate the trade-off between economic and environmental in the long-term. It will be next to impossible to derive a optimal generation mix that simultaneously considers the core values, such as supply stability, environmental performance, economic efficiency, energy safety and energy security, when establishing the power supply and demand plan. However, by exploring the effects of various generation mix paths and suggesting near-optimal paths, people can best choose their direction after weighhing all the paths when deciding on a forward-looking generation mix in the long term.

• 한국노년학
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• v.37 no.1
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• pp.15-32
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• 2017

The current study aims to identify the heterogeneous changes of functional disabilities in old age rather than to identify an average longitudinal pattern and to explore the effect of health status and social status as risk factors in functional disability trajectories. The sample consisted of a representative sample of community dwellers aged 65 and older from the Korean Longitudinal Study of Ageing (2006 - 2012) was the focus of the study. Latent Class Growth Analysis was used to identify the functional disability trajectory groups. Variables regarding health status and social status changes by class were identified using multinomial logistic regression. The results showed various change patterns in functional disability, which include independent (78%), stable high (4.4%), steeply increasing (7.1%), slightly increasing (5.5%), and moderate to low (4.7%). Aggravation in depressive symptoms and cognitive functions as well as decline in social participations and social engagements were significant predictors of membership in increasing group of functional disability. The findings provide important initial empirical information to target clinical practice and have implications in the importance of conducting research on groups with different characteristics.