• 한국해안·해양공학회논문집
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• 제20권1호
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• pp.62-72
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• 2008

본 연구에서는 흐름에 수직한 방향으로 급격한 수심 변화가 존재하는 해역에서 점열원에 의한 열오염 분포를 예측할 수 있는 해석 모델을 개발하였다. 개발된 모델을 이용하여 열오염 분포에 있어 수심 변화와 흐름효과를 검토하였다. 계산 결과 흐름에 수직한 방향으로 수심 변화가 존재할 경우 수평 확산 플럭스의 증감으로 인해 수심 변화 경계를 가로지르는 열의 이동이 증가하거나 감소하는 것으로 나타났다. 조류와 동시에 잔차류 성분을 포함할 경우에는 이류에 의한 열오염 수송 효과가 증가하여 수심 변화 경계를 가로지르는 수평 확산은 상대적으로 감소하였다.

• 수산해양교육연구
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• 제28권6호
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• pp.1834-1847
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• 2016

Main objectives of the this study are: to develop a model of "Flipped Leaning" that is designed to enhance self-directed learning, learning motivation and self-control, and to verify its effectiveness-in higher education. The verification process initially concentrated on the feasibility study of the model with a thorough literature review and case analyses; then, its general and practical applicability were tested with a field study. As a result, first, the CHANGE Class Model, specifically designed for effective and efficient "Flipped Learning", was developed. It is thus named for the stages that the learning process takes place in the model-i.e., (1) Check ${\rightarrow}$ (2) Ask ${\rightarrow}$ (3) Notice ${\rightarrow}$ (4) Group presentation ${\rightarrow}$ (5) Evaluation, and it emphasizes the dynamic, questions centered (i.e. back and forth between the students and the instructor as well as between the students) learning process. Second, the Model was instrumental in enhancing self-directed learning, learning motivation and self-control; thus, as a result, it significantly improved the effectiveness, the level of concentration and the attractiveness of the learning process. The value of this study lies in pointing to a clear plan to allow a student in higher learning to set-up a self-directed learning plan, to be able to control it while being continuously motivated to complete it.

• 한국과학교육학회지
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• 제21권5호
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• pp.822-840
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• 2001

This article presents a theoretical model for conceptual change that relates cognitive conflict and the role of context. The model assumes that students derive alternative conceptions from everyday contexts while scientific concepts presume an idealized context, and hence, that the source of cognitive conflict results from the difference between the two contexts. Test results and analysis of the model are presented by applying it in a class studying the inertial motion of bodies. The subjects are 37 seventh grade boys.

• Journal of the Korean Data and Information Science Society
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• 제18권1호
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• pp.11-16
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• 2007

Since the seminal work of Engle (1982), many researchers and practitioners have developed ARCH-type models to deal with volatility modelling, which, for instance, is crucial to perform the task of derivative pricing, measuring risk, and risk hedging. In this paper, we base the GARCH(1,1) model to analyze the KOSPI200 data, and perform the CUSUM test for detecting parameter changes in the GARCH model. It is shown that the data suffers from a parameter change.

• 한국농공학회논문집
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• 제62권5호
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• pp.47-62
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• 2020

Rice paddy accounts for approximately 52.5% of all farmlands in South Korea, and it is closely related to the water environment. Climate change is expected to affect not only agricultural productivity also the water and the nutrient circulation. Therefore this study was aimed to evaluate changes of nitrogen load from rice paddy considering climate change scenario uncertainty. APEX-Paddy model which reflect rice paddy environment by modifying APEX (Agricultural Policy and Environmental eXtender) model was used. Using the AIMS (APCC Integrated Modeling Solution) offered by the APEC Climate Center, bias correction was conducted for 9 GCMs using non-parametric quantile mapping. Bias corrected climate change scenarios were applied to the APEX-Paddy model. The changes and uncertainty in runoff and nitrogen load were evaluated using multi-model ensemble. Paddy runoff showed a change of 23.1% for RCP4.5 scenario and 45.5% for RCP8.5 scenario compared the 2085s (2071 to 2100) against the base period (1976 to 2005). The nitrogen load was found to be increased as 43.9% for RCP4.5 scenario and 76.0% for RCP8.5 scenario. The uncertainty analysis showed that the annual standard deviation of nitrogen loads increased in the future, and the maximum entropy indicated an increasing tendency. And Duncan's analysis showed significant differences among GCMs as the future progressed. The result of this study seems to be used as a basis for mid- and long-term policies for water resources and water system environment considering climate change.

• 한국경영과학회지
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• 제12권1호
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• pp.19-26
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• 1987

In analyzing time series, estimating the level or the current mean of the process plays an important role in understanding its structure and in being able to make forecasts. The studies the class of time series models where the level of the process is assumed to follow a random walk and the deviation from the level follow an ARMA process. The estimation and forecasting problem in a Bayesian framework and uses the Kalman filter to obtain forecasts based on estimates of level. In the analysis of time series, we usually make the assumption that the time series is generated by one model. However, in many situations the time series undergoes a structural change at one point in time. For example there may be a change in the distribution of random variables or in parameter values. Another example occurs when the level of the process changes abruptly at one period. In order to study such problems, the assumption that level follows a random walk process is relaxed to include a major level change at a particular point in time. The major level change is detected by examining the likelihood raio under a null hypothesis of no change and an alternative hypothesis of a major level change. The author proposes a method for estimation the size of the level change by adding one state variable to the state space model of the original Kalman filter. Detailed theoretical and numerical results are obtained for th first order autoregressive process wirth level changes.

• 수산경영론집
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• 제46권3호
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• pp.63-72
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• 2015

This study aims to empirically analyze the relationship between climate change elements and catch amount of coastal fisheries, which is predicted to be vulnerable to climate change since its business scale is too small and fishing ground is limited. Using panel data from 1974 to 2013 by region, we tested the relationship between the sea temperature, salinity and the coastal fisheries production. A spatial panel model was applied in order to reflect the spatial dependence of the ocean. The results indicated that while the upper(0-20m) sea temperature and salinity have no significant influence on the coastal fisheries production, the lower(30-50m) sea temperature has significant positive effects on it and, by extension, on the neighboring areas's production. Therefore, with sea temperature forecast data derived from climate change scenarios, it is expected that these results can be used to assess the future vulnerability to the climate change.

• 대한화학회지
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• 제61권4호
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• pp.204-210
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• 2017

이 연구에서는 2009개정 교육과정 및 화학 I 교과서에 제시된 전자 이동 모델과 산화수 변화 모델의 서술방식을 분석하고, 화학교육전공 교사들을 대상으로 각 모델의 제한 조건에 대한 인식을 알아보았다. 교육과정과 교과서에서는 전자 이동 모델, 산화수 변화 모델을 제시하고 있으나, 각 모델의 제한 조건을 무시한 혼성 모델도 있었다. 혼성 모델은 공유결합 물질의 산화 환원 반응을 전자 이동 모델로 기술하거나 산화수 개념으로 설명하는 경우에도 가상적인 전자 이동과 실제적인 전자 이동을 혼동하게 하는 문제를 가진다. 산화 환원 반응에 대한 화학교육전공 교사들의 인식을 조사하기 위하여 설문지 및 면담을 실시하였다. 연구 결과, 많은 교사들이 각 모델의 제한 조건을 인식하지 못하고 있었으며, 혼성 모델로 인해 산화 환원 반응을 산 염기반응과 구분하는데 어려움을 가지는 것으로 나타났다.

• 공학교육연구
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• 제19권5호
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• pp.57-64
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• 2016

This study is about interdisciplinary education model of using Davis Guggenheim's documentary film on global warming which is a big concern in climate change issues, An Inconvenient Truth. It based on Al Gore's slide speech. Through a course student analyzed the cause and phenomenon of global warming resulted from increase of $CO_2$ by using fossil fuel and its environmental science effects-heat wave, desertification, tornado, hurricane, sea level rise caused by melting glaciers, destroying ecosystem like habitat degradation of wild animals, for example polar bear, extreme cold wave caused by change of ocean currents- of global warming. After, student discussed of efforts to prevent global warming. This educational model is appropriate for lower grade student of environmental engineering and also available for converged majors or general education class.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.203-211
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• 2009

Korean public owners who order public multi-family housing construction projects have yet to gain access to a model for predicting construction cost. For this reason, their construction cost prediction is mainly dependent upon historic data and experience. In this paper, a cost-prediction model based on Case-Based Reasoning (CBR) in the design phase of public multi-family housing construction projects was developed. The developed model can determine the total construction cost by estimating the different Building, Civil, Mechanical, Electronic and Telecommunication, and Landscaping work costs. Model validation showed an accuracy of 97.56%, confirming the model's excellent viability. The developed model can thus be used to predict the construction cost to be shouldered by public owners before the design is completed. Moreover, any change orders during the design phase can be immediately applied to the model, and various construction costs by design alternative can be verified using this model. Therefore, it is expected that public owners can exercise effective design management by using the developed cost prediction model. The use of such an effective cost prediction model can enable the owners to accurately determine in advance the construction cost and prevent increase or decrease in cost arising from the design changes in the design phase, such as change order. The model can also prevent the untoward increase in the duration of the design phase as it can effectively control unnecessary change orders.