• Geophysics and Geophysical Exploration
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• v.15 no.2
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• pp.66-74
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• 2012

This paper presents development of a three-dimensional marine controlled-source electromagnetic (mCSEM) modeling algorithm and its application to a salt and reservoir model to examine detectability of mCSEM for a reservoir under complex subsurface structures. The algorithm is based on the finite difference method, and employs the secondary field formulation for an accurate and fast calculation of modeling responses. The algorithm is verified for a two-layer model by comparing solutions not only with analytic solutions but also with those from other 3D modeling algorithm. We calculate and analyze electric and magnetic fields and their normalized responses for a salt and reservoir model due to three sources located at boundaries between a salt, a reservoir, and background. Numbers and positions of resistive anomalies are informed by normalized responses for three sources, and types of resistive anomalies can be informed when there is a priori information about a salt by seismic exploration.

• Journal of the Korean Magnetics Society
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• v.8 no.4
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• pp.231-240
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• 1998

We investigated that the fabrication and reproducing signal characteristics of tri-layered magnetoresistance (MR) element for the high density magnetic thin film heads and sensors. Magnetoresistance curve of tri-layered MR element predicted by computer modeling was saturated above external field of -15 Oe~+22 Oe, and it was shifted to linearized region as large as 4 Oe. In the case of fabricated real device, magnetoresistance curve was saturated above external field of $\pm$15 Oe, and it was shifted to linearized region as large as 4 Oe. As shown in real device, MR response curve was in good agreement with the simulation results. As a result of experimental data of reproducing output signal in real device, it retained normal sinusoidal waveforms in 1~4 Oe external magnetic field. In this magnetic field region, the fabricated heads with tri-layered MR element can be operated with good reproduced characteristics. This will be beneficial to the use of efficient processes of manufacturing elements and the vacuum deposition techniques which control thin film properties.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.34 no.3
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• pp.183-204
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• 2023

The purpose of this study is to present a construction model of Koryoin Larchiveum that considers the space and function of larchiveum, centering on the Koryoin Historical and Cultural Center. To this end, a survey was conducted targeting librarians, archivists, and curators, and multivariate analysis of variance (MANOVA) was conducted to find out the average difference between space and work requirements by institution. In addition, based on the survey, in-depth interviews were conducted with secondary experts (directors, representatives, Koryoin experts, etc.) on spatial components. As a result, first, spatial and functional elements set mainly for functions necessary for Koryoin Larchiveum were derived. Spatial elements include storage, reading rooms, and resting areas for libraries, archives storage rooms and exhibition rooms for archives, and storage and exhibition rooms for cultural centers. Functions (work) were represented by 4 elements: library 3, archives 5, and cultural center. Second, after reviewing the interview, the Koryoin Larchiveum construction model was modified and supplemented. As for the spatial composition, the installation space, work contents, and manpower in charge were presented from the first basement floor to the third floor above the ground.

• Korea journal of population studies
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• v.29 no.1
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• pp.209-239
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• 2006

본 연구는 총부양비를 최소화하는 적정인구성장률을 인구학적 부양비와 경제적 부양비로 나누어 계산하구 그것이 무엇을 의미하가를 연구하는 것이 목적이다. 이 연구를 위하여 연구모형을 제시하고, 합계출산율과 적정인구성장률의 관계를 명시하며, 그것이 궁극적으로 적정인구 규모에 어떤 의미를 갖는가를 탐색한다. 인구학적 부양비를 최소화하는 인구성장률은 $-0.03%{\sim}0.15%$의 범위에 있으며, 그것은 합계 출산율로는 $2.1{\sim}2.2$명에 해당한다. 경제적 부양비를 최소화하는 인구성장률은 유년층과 노년층의 상대적 개인 소비비중에 따라 인구성장률과 그것이 함의하는 합계출산율은 달라진다. 예컨대, $u_1:u_3=2:1$일 때 적정인구성장률은 $-1.17{\sim}-0.93%$, 그것이 함의하는 합계출산율은 $1.5{\sim}1.6$명이다. 한편 유년층 대비 노년층의 상대적 소비비중이 증가하는 경우에는 적정인구성장율이 높아져야 한다. 예컨대 $u_1:u_2=1:1.2$일 때 적정인구성장률은 $0.42{\sim}0.45%$이고, 그것이 함의하는 합계출산율은 $2.3{\sim}2.4$명이다. 본 연구에서 적정인구추계를 위한 기초 여론조사에 따라 진행된 상대적 소비비중을 계산한 결과에 따르면, 유년층과 노년층의 상대적 개인 소비비중은 $u_1:u_2=1.25:1$이며, 이에 따른 현재의 상황에서 한국의 적정출산율은 $1.9{\sim}2.0$명 수준으로, 이에 해당하는 적정인구성장률은 대략 약간의 네거티브 성장을 하는 경우라고 할 수 있을 것이다.

• Journal of the Korean Geotechnical Society
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• v.19 no.3
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• pp.39-44
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• 2003

Centrifuge test was conducted to simulate the effects of consolidation settlement of capped contaminated marine sediment. A fluorescent dye was used to monitor the movement of pore water through the cap layer. Dye tracer study clearly showed the consolidation induced advective transport of contaminants. Thus, the capping layer must be appropriately designed to reduce the effects of consolidation induced advective transport. The results from the centrifuge test were compared to predictions made by the Primary consolidation, Secondary compression, and Desiccation of Dredged Fill (PSDDF) computer program, which can qualitatively estimate the consolidation settlement of capped marine sediment. Although PSDDF approximated closely the secondary compression in the centrifuge test (i.e., compare data points from 18 to 25 prototype years), the maximum deviation between centrifuge test result and PSDDF prediction was 20 % about prototype time 6 years. Thus, designers should utilize PSDDF consolidation settlement results with caution.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.2
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• pp.162-169
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• 2007

This study is focused on the comparison of a 3 dimensional numerical and hydraulic model experiment for the flow phenomenon when a lock gate is opened. The lock gate is designed to discharge the flood flow rate at $218m^3/s$ of Solicheon at the Kun Jang national industry complex. The three dimensional ${\kappa}-{\epsilon}$ turbulent model of ANSYS CFX-10 of the computational fluid dynamics(CFD) program was used. The characteristics of CFX-10 are able to be simulated effectively for turbulent flow, especially the flow separation of the boundary layer of the two phase interface of air and water. The velocity and the flow pattern of the numerical model was showed to be similar to the results of the hydraulic model experiment.

• Journal of the Korean earth science society
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• v.29 no.3
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• pp.263-279
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• 2008

This study is concerned with the optimization of models using MM5 and WRF mesoscale numerical models to simulate strong sea surface winds, such as that of typhoon Shanshan on 17 September 2006, and the Siberian high event on 16 December 2006, which were selected for displaying the two highest mean wind speeds. The model optimizations for the lowest level altitude, physical parameters and horizontal resolution were all examined. The sea surface wind values obtained using a logarithmic function which takes into account low-level stability and surface roughness were more accurate than those obtained by adjusting the lowest-level of the model to 10 m linearly. To find the optimal parameters for simulating strong sea surface winds various physical parameters were combined and applied to the model. Model grid resolutions of 3-km produced better results than those of 9-km in terms of displaying accurately regions of strong wind, low pressure intensities and low pressure mesoscale structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.597-603
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• 2006

The purpose of this study is to improve the short term rainfall forecast skill using neural network model that can deal with the non-linear behavior between satellite data and ground observation, and minimize the flood damage. To overcome the geographical limitation of Korean peninsula and get the long forecast lead time of 3 to 6 hour, the developed rainfall forecast model took satellite imageries and wide range AWS data. The architecture of neural network model is a multi-layer neural network which consists of one input layer, one hidden layer, and one output layer. Neural network is trained using a momentum back propagation algorithm. Flood was estimated using rainfall forecasts. We developed a dynamic flood inundation model which is associated with 1-dimensional flood routing model. Therefore the model can forecast flood aspect in a protected lowland by levee failure of river. In the case of multiple levee breaks at main stream and tributaries, the developed flood inundation model can estimate flood level in a river and inundation level and area in a protected lowland simultaneously.

• Journal of Korea Water Resources Association
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• v.32 no.3
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• pp.301-310
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• 1999

In this paper a numerical model and two analytical models in the hydraulically connected stream-aquifer system were analyzed to compare the induced infiltration rate curves derived from each model. And we also examined the effects of anisotropy of hydraulic conductivity and the direction of the ambient ground water flow on the quantification of the induced infiltration rate. The induced infiltration rate curve determined by models is very simple and useful for estimating the induced infiltration rate since it contains only four physical variables such as the induced infiltration rate, the pumping rate, the distance between the pumping well and the stream, and the ambient ground water flow rate. Under the conditions tested in this paper the induced infiltration rate curves resulted from the Wilson's analytical model and FEWA numerical model were in good agreement, and the anisotropic ratio of hydraulic conductivity was evaluated as a physical factor which influences the behaviour of the induced infiltration rate curve. The methods and results of the paper might Icad to improve the understanding of the induced infiltration phenomenon and can be applied to the planning and disign of pumping well and the optimal determination of the induced infiltration rate and pumping rate for water quality management of the water supply wells.

• Journal of the Korea Society of Computer and Information
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• v.28 no.11
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• pp.53-63
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• 2023

This study developed a cognitive impairment predictive model as one of the screening tests for preventing dementia in the elderly by using Automated Machine Learning(AutoML). We used 'Wearable lifelog data for high-risk dementia patients' of National Information Society Agency, then conducted using PyCaret 3.0.0 in the Google Colaboratory environment. This study analysis steps are as follows; first, selecting five models demonstrating excellent classification performance for the model development and lifelog data analysis. Next, using ensemble learning to integrate these models and assess their performance. It was found that Voting Classifier, Gradient Boosting Classifier, Extreme Gradient Boosting, Light Gradient Boosting Machine, Extra Trees Classifier, and Random Forest Classifier model showed high predictive performance in that order. This study findings, furthermore, emphasized on the the crucial importance of 'Average respiration per minute during sleep' and 'Average heart rate per minute during sleep' as the most critical feature variables for accurate predictions. Finally, these study results suggest that consideration of the possibility of using machine learning and lifelog as a means to more effectively manage and prevent cognitive impairment in the elderly.