• Journal of Soil and Groundwater Environment
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• v.10 no.3
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• pp.24-31
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• 2005

This study presents a contaminant transport model suitable for a 2-dimensional heterogeneous aquifer with multiple contaminant sources. It uses a streamline simulation, which transforms a multi-dimensional problem into multiple 1dimensional problems. It runs flow simulation, streamline tracking, and calculation of contaminant concentrations by turns. The model is verificated with a Visual MODFLOW by comparing contaminant concentration distributions and breakthrough curves at an observation well. Due to its fast simulation, it can be applied to time consuming simulations such as in a fine-grided aquifer, an inverse modeling and other applications.

• Journal of Broadcast Engineering
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• v.23 no.3
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• pp.351-360
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• 2018

Human emotion recognition is a research topic that is receiving continuous attention in computer vision and artificial intelligence domains. This paper proposes a method for classifying human emotions through multiple neural networks based on multi-modal signals which consist of image, landmark, and audio in a wild environment. The proposed method has the following features. First, the learning performance of the image-based network is greatly improved by employing both multi-task learning and semi-supervised learning using the spatio-temporal characteristic of videos. Second, a model for converting 1-dimensional (1D) landmark information of face into two-dimensional (2D) images, is newly proposed, and a CNN-LSTM network based on the model is proposed for better emotion recognition. Third, based on an observation that audio signals are often very effective for specific emotions, we propose an audio deep learning mechanism robust to the specific emotions. Finally, so-called emotion adaptive fusion is applied to enable synergy of multiple networks. The proposed network improves emotion classification performance by appropriately integrating existing supervised learning and semi-supervised learning networks. In the fifth attempt on the given test set in the EmotiW2017 challenge, the proposed method achieved a classification accuracy of 57.12%.

• Journal of the Korean Society for Heat Treatment
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• v.2 no.2
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• pp.1-10
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• 1989

In this study, the specimens of SCM 22 H steel were quenched in oil and water baths at various agitation conditions in order to investigate the effects of quenchants and agitation conditions on the quench-hardening. A multi-channel temperature measurement apparatus was employed to obtain the cooling curves at several predetermined positions of specimens. Microstructural observation and hardness test were also carried out. Computer simulation of heat treating process was carried out using the modified finite difference method. Prediction of thermal history and hardness distribution by 2-dimensional computer analysis was in good agreement with the experimental results. It was found that the quantitative design of heat treating process can be made by the computer aided heat-treating analysis.

• Journal of Korea Water Resources Association
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• v.30 no.5
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• pp.441-447
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• 1997

Rainfall observation using rain gage network or satellites includes the sampling error depending on the observation methods or plans. For example, the sampling using rain gages is continuous in time but discontinuous in space, which is nothing but the source of the sampling error. The sampling using satellites is the reverse case that continuous in space and discontinuous in time. The sampling error may be quantified by use of the temporal-spatial characteristics of rainfall and the sampling design. One of recent works on this problem was done by North and Nakamoto (1989), who derived a formulation for estimating the sampling error based on the temporal-spatial rainfall spectrum and the design scheme. The formula enables us to design an optimal rain gage network or a satellite operation plan providing the statistical characteristics of rainfall. In this paper the formula is reviewed and applied for the sampling error problems using several multi-dimensional precipitation models. The results show the limitation of the formulation, which cannot distinguish the model difference in case the model parameters can reproduce similar second order statistics of rainfall. The limitation can be improved by developing a new way to consider the higher order statistics, and eventually the probability density function (PDF) of rainfall.

• Korean Security Journal
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• no.31
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• pp.157-185
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• 2012

Today, the emergence of cyberspace and advancement of globalization caused not only the transformation of our productive and conventional life but also the revolutionary transition of use of destructive violence such as crime and warfare. This transition of environmental condition connects various security threats which separatedly existed in individual, local, national, and global levels in the past, and transformed the mechanical sum of all levels of security threats into the organic sum of multi-dimensional security threats. This article proposes that the sum of multi-dimensional security threats is caused by the interconnectivity of various different levels of security threats and the integrated interdisciplinary perspective is essential to properly understand the fundamental existence of today's security problem and the reality of fear that we face today. The holistic security, the concept proposed here, is to suggest the mode of networked response to multi-dimensional security threats. The holistic security is suggested to overcome the conventional divisional approach based on the principle of "division of labor" and bureaucratic principles, which means more concretely that national security and criminal justice are divided and intelligence, military, police, prosecution, fire-fighting, private security, and etc. are strictly separated into its own expertise and turf. Also, this article introduces integrated security approaches tried by international organization and major countries overseas with the respect of the holistic security. The author have spent some substantial experience of participant observation, meetings, seminar, conference, and expert interviews regarding the issues discussed in the article in various countries including the United States, Russia, Austria, Germany, Canada, Mexico, Israel, and Uzbekistan for the last ten years. Intelligence and information on various levels of security threats and security approaches introduced in this paper is obtained from such opportunities.

• Geotechnical Engineering
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• v.1 no.1
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• pp.59-72
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• 1985

This paper deals with the numerical analysis by the (mite element method introducing Biot's theory of consolidation and the modified Cambridge model proposed by Roscoe school of Cambridge University as constitutive equation and using Christian-Boehner's technique. Especially, time interval and division of elements are investigated in vies of stability and economics. In order to check the validity of author's program, the program was tested with one-dimensional consolidation case followed by Terzaghi's exact solution and with the results of the Magnan's analysis for existing banking carried out for study at Cubzac-les-ports in France. The main conclusions obtained are summarized as follows: 1. In the case of one-dimensional consolidation, the more divided the elements are near the surface of the foundation, the higher the accuracy of the numerical analysis is. 2. For the time interval, it is stable to divide 20 times per 1-lg cycle. 3. At the element which has long drain distance, the Mandel-fryer effect appears due to time lag. 4. Lateral displacement at an initial loading stage predicted by author's program, in which the load was assumed as not concentrative. but rather in grid form, is well consistent with the value of observation. 5. The pore water pressure predicted by author's program has a better accordance with the value of observation compared with Magnan's results. 6. Optimum construction control by Matsuo-Kawamura's method is possible with the predicted lateral displacement and settlement by the program.

• Journal of dental hygiene science
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• v.14 no.4
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• pp.455-460
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• 2014

This study compared the surface roughness and surface characteristics between a type IV stone and scannable stone. Materials used were a type IV stone, two different kind of scannable stone. Ten specimens per experimental group were prepared according to manufacturer's direction. Surface roughness of specimen was measured using profilometer. The measurement was based on the standard of Japanese Industrial Standards 1994. The mean and standard deviations of each reference point were analyzed using one-way ANOVA and Scheff$\acute{e}$ post hoc test. The program used to handle statistical analysis was SPSS 20.0 and the significance level was set at 0.05. The difference of surface roughness was statistically significant in order of Scannable Stone $10.07{\pm}0.02{\mu}m$, Scannable Stone $20.08{\pm}0.03{\mu}m$, Type IV $0.10{\pm}0.04{\mu}m$. These results will have to be confirmed in further clinical application researches.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.4
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• pp.275-281
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• 2019

A synthetic aperture radar(SAR) satellite is more effective than an optical satellite for target analysis because an SAR satellite can provide two-dimensional electromagnetic scattering distribution of a target during all-weather and day-and-night operations. To conduct target analysis while considering the earth observation interval of an SAR satellite, observing a specific area as wide as possible would be advantageous. However, wider the observation area, worse is the resolution of the associated SAR satellite image. Although conventional methods for improving the resolution of radar images can be employed for addressing this issue, few studies have been conducted for improving the resolution of SAR satellite images and analyzing the performance. Hence, in this study, the applicability of conventional methods to SAR satellite images is investigated. SAR target detection was first applied to Korea Multipurpose Satellite-5(KOMPSAT-5) SAR images provided by Korea Aerospace Research Institute for extracting target responses. Extrapolation, RELAX, and MUSIC algorithms were subsequently applied to the target responses for improving the resolution, and the corresponding performance was thereby analyzed.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.52.2-52.2
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• 2011

We searched and studied galaxy overdensities at 0.6 < z < 4.5 in the areas of two GOODS fields. These overdensities are identified by running top-hat filters on the two dimensional spatial distribution of two galaxy samples - a K-band limited, photometric redshift sample at 0.6 < z < 4.5, and BVz-color selected sample targeting overdensities at z ~ 3.7 and z ~ 4.0. Here photometric redshifts are derived from multi-wavelength data ranging from U-band through 8 micron band of the Spitzer. We find 52 overdensities with significances of 3.5-7 ${\sigma}$. The derived masses found to be a > $10^{13}\;M_{\odot}$ with the comoving number density of a few ${\times}10^{-6}\;Mpc^{-3}$ at z ~ 3. In order to understand the high number density of massive overdensities at high redshift, we carried out an analysis of galaxy overdensities using the mock galaxy catalog based on Millennium simulation selected in the same way as the analysis of the observational data. In the simulation, we find 650 galaxy overdensities with a 3.5 ${\sigma}$ detection threshold over $2^{{\circ}2}$ sky field. The number density of the very massive overdensities (M > $10^{14}\;M_{\odot}$) in simulation shows a similar trend with the observation. We further discuss implications of our results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.4
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• pp.397-404
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• 2010

The use of equivalent circuit models of piezoelectric energy harvesters is inevitable when power circuitry including rectifying and smoothing circuit elements is connected to them for evaluating DC electrical outputs. This is because it is difficult to incorporate the electro-mechanical coupling resulting from the additional circuitry into the conventional finite element analysis. Motivated by this observation, we propose a method to accurately extract the equivalent circuit parameters by using commercially available FEM software such as ANSYS which provides three-dimensional AC piezoelectric analysis. Then the equivalent circuit can be analyzed by circuit simulators such as $SimPowerSystems^{TM}$ of MATLAB. While the previous works have estimated the circuit parameters by experimental measurements or by analytical solutions developed only for limited geometries and boundary conditions, the proposed method has no such limitation because piezoelectric energy harvesters of any shapes and boundary conditions can be treated in FEM software. For the verification of the proposed method, multi-modal AC electrical power output by using a corresponding equivalent circuit is compared with that by ANSYS. The proposed method is then shown to be very useful in the subsequent evaluation of DC electrical output which is obtained by attaching a bridge diode and a storage capacitor to a piezoelectric energy harvester.