• Korean Journal of Cognitive Science
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• v.20 no.2
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• pp.155-181
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• 2009

Psychophysiologists are often interested in the EEG signals that accompany certain psychological events. When one is interested in a time series of event-related changes in EEG, one focuses on examining how the waveforms recorded at individual electrode sites vary over time across one or more experimental conditions. This is an analysis of event-related potentials (ERPs). In addition to such a classical EEG analysis in the time domain, the EEG measures can be investigated in the frequency domain. Moreover, it has been demonstrated that spectral analyses can often yield significant insight into the functional cognitive correlations of the signals. Therefore, this review paper tries to summarize essential concepts (e.g. phase-locking) and conventional methods (e.g. wavelet transformation) for understanding spectral analyses of brain oscillatory activity. Phase-coherence is also introduced in relation to functional connectivity of the brain.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.3
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• pp.251-260
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• 2003

A three dimensional (3-D) method of analysis is presented for determining the free vibration frequencies and mode shapes of deep, tapered rods and beams with circular cross section. Unlike conventional rod and beam theories, which are mathematically one-dimensional (1-D), the present method is based upon the 3-D dynamic equations of elasticity. Displacement components u/sup r/, u/sub θ/ and u/sub z/, in the radial, circumferential, and axial directions, respectively, are taken to be sinusoidal in time, periodic in , and algebraic polynomials in the r and z directions. Potential (strain) and kinetic energies of the rods and beams are formulated, the Ritz method is used to solve the eigenvalue problem, thus yielding upper bound values of the frequencies by minimizing the frequencies. As the degree of the polynomials is increased, frequencies converge to the exact values. Convergence to four-digit exactitude is demonstrated for the first five frequencies of the rods and beams. Novel numerical results are tabulated for nine different tapered rods and beams with linear, quadratic, and cubic variations of radial thickness in the axial direction using the 3D theory. Comparisons are also made with results for linearly tapered beams from 1-D classical Euler-Bernoulli beam theory.

• The Journal of the Korea Contents Association
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• v.22 no.1
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• pp.405-414
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• 2022

The purpose of this study is to discover the possibility to expand the aesthetic interpretation of dance works. For this purpose, this study analyzes Maguy Marin's (1981) because it shows Sigmund Freud's concept of uncanny and grotesque images well. The theoretical framework of this study was centered on previous academic studies, and Hoffman's Der Sandmann(1816) was presented as an example to help the conceptual understanding of uncanny and grotesque. The analysis of of Magi Marin was divided into stage space, dancer's movements, costumes, and voice. As a result of this study, it was discovered that is a work with an experimental spirit that deviated from the stereotypes of traditional stage aesthetics. And it was implemented as uncanny and grotesque images in the choreography structure. In addition, as the changes of the times have a great influence on the creation of dance works, it is thought that the discourse of various aesthetic interpretation methods in dance works can provide various directions for dance creation in the future. Therefore, this study will be helpful in raising the aesthetic value and status of dance art.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.41 no.4
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• pp.30-39
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• 2023

This study aims to identify the value of Incheon Freedom Park as a 'historic urban park' through the historical transition process of the park and surrounding areas. To this end, this study uses a time series analysis, as research method, based on old maps and aerial photographs to investigate the changes in the park over time and to interpret them based on the historical and cultural changes in modern and contemporary history. As a result of the study, the park not only has (1) evidence of major events in modern and contemporary history, but also (2) historical value as an urban park based on the first urban plan in Korea, and (3) very important heritage value that shows the rapidly changing civic life in modern and contemporary times. However, despite the identification of heritage values in this study, further research is needed to explore and excavate in-depth data on the park in order to more clearly identify, restore, and utilize the heritage values of the park.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.107-112
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• 2017

This paper performed an experimental study to test the validity of the prospect theory proposed by Tversky and Kahneman as an alternative to the expected utility theory. 115 college students attended the hypothetical games to choose one of two lotteries, one is safe option while the other one is risky. The risky options were set up to have low, medium or high probability of payoffs or losses. The amount of payoffs and losses of the lotteries was either large or small. Maximum likelihood estimation of the hypothetical games have shown that in case of high probability of positive payoffs the respondents were risk averse and when the probability of positive payoffs were small the respondents were risk loving. when the possibility of loss is high they were risk loving, while the probability is of loss is low the respondents were found to be risk averse. When the probability of risky options were medium the results were significant statistically in case of only losses. The amount of positive payoff or losses does not affect the results. Overall the results of this experiments support the prospect theory more than those of Laury & Holts (2008).

• Information Systems Review
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• v.10 no.2
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• pp.235-251
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• 2008

With the successful arrival of quality free/open source software, open source ISD(Information System Development) projects have been drawing attention from academic researchers. However, there have been few efforts to examine the managerial aspect of open source ISD projects. This study use a case research methodology to explores the management of open source projects, especially from the perspective of behavior control. Through data analysis and discussion, the study found that various practices related to behavior control were exercised to obtain participants' shared goals, although specific instances vary in each case. This finding is contradictory to the views of some researchers who suggested open source ISD projects lack behavior control. For more comprehensive understanding, however, future research should also include controls of open source projects in terms of outcome control and self-control.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.598-603
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• 2023

Electrochemical ammonia production using catalysts offers a promising alternative to the conventional Haber-Bosch process, allowing for ambient temperature and pressure conditions, environmentally friendly operations, and high-purity ammonia production. In this study, we focus on the nitrogen reduction reactions occurring on the surfaces of ruthenium catalysts, employing first-principles calculations. By modeling reaction pathways for nitrogen reduction on the (0001) and (1000) surfaces of ruthenium, we optimized the reaction structures and predicted favorable pathways for each step. We found that the adsorption configuration of N₂ on each surface significantly influenced subsequent reaction activities. On the (0001) surface of ruthenium, the end-on configuration, where nitrogen molecules adsorb perpendicularly to the surface, exhibited the most favorable N₂ adsorption energy. Similarly, on the (1000) surface, the end-on configuration showed the most stable adsorption energy values. Subsequently, through optimized hydrogen adsorption in both distal and alternating configurations, we theoretically elucidated the complete reaction pathways required for the final desorption of NH₃.

• Communications of Mathematical Education
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• v.19 no.2 s.22
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• pp.389-407
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• 2005

수학은 위계적이고 구조적인 특성을 가지고 있어서 학생들이 적절하게 학습하면 내적 동기유발이 가능하고 흥미 있게 학습해 나갈 수 있는 반면 단편적인 지식들로 학습하려 한다면 그 양이 방대해지고 제대로 이해하기가 어렵다. 그러므로 교사는 수학적 지식의 구조를 깨달아 지식의 본체가 내적으로 어떻게 조직되고 상호 관련되어 있는지 알아야 하고 학생들이 수학적인 아이디어와 절차를 획득하고 탐구하게 하는 적절한 문제를 제시하여 문제해결을 통해 가르쳐 가는 방법을 생각해야 할 것이다. 이 때에 학생들은 문제해결 과정에서 능동적인 역할을 하면서 자신이 학습하고 있는 것의 핵심을 인식하고 호기심을 갖고 유의미한 기능들을 이끌어내는 학습을 해야 하는데, 이는 오랜 전통의 탐구 학습과 그 맥락을 같이 하는 것이다. 수학교과 고유의 특성을 살려 지식의 구조를 가르침에 있어서 교수 방법으로의 문제해결을 통한 지도와 학습 방법으로의 탐구학습 과정은 잘 조화될 수 있다. 이러한 조화된 모습을 드러나게 하고자 초등학교 5학년 가 단계에서 '평면도형의 넓이와 둘레 사이의 관계'를 탐구하게 하는 문제해결을 통한 탐구학습 과제를 제시해 보았다. 30-40년을 거슬러 올라가는 역사를 갖는 지식의 구조나 탐구학습, 문제해결에 대한 관심은 오늘날에도 여전히 시사하는 바가 크다고 하겠다. 수학교육에 관한 연구들은 완전히 새로운 것이기보다는 이전의 것들이 주는 의미를 되새기고 오늘의 상황에 비추어 해석할 때 수학교육은 한 단계 올라서게 된다.

• Journal of Korea Water Resources Association
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• v.35 no.1
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• pp.1-12
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• 2002

This study was intended to investigate the rainfall-runoff relationship with spatially distributed rainfall data, and then, to analyze and quantify the uncertainty induced by spatially averaging rainfall data. For constructing spatially distributed rainfall data, several historical rainfall events were extended spatially by simple kriging method based on the semivariogram as a function of the relative distance. Runoff was computed by two models; one was the modified Clark model with spatially distributed rainfall data and the other was the conventional Clark model with spatially averaged rainfall data. Rainfall errors and discharge errors occurred through this process were defined and analyzed with respect to various rain-gage network densities. The following conclusions were derived as the results of this work; 1) The conventional Clark parameters could be appropriate for translating spatially distributed rainfall data. 2) The parameters estimated by the modified Clark model are more stable than those of the conventional Clark model. 3) Rainfall and discharge errors are shown to be reduced exponentially as the density of rain-gage network is increased. 4) It was found that discharge errors were affected largely by rainfall errors as the rain-gage network density was small.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.555-567
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• 2013

A finite element formulation for a Rayleigh-damped Bernoulli-Euler beam subjected to support motions, which accompanies quasi-static rigid-body motion, is presented by using the quasi-static decomposition method. Moving support beam elements, one of whose nodes is coincident with the moving support, are developed to represent the effect of a moving support. Statically determinate beams subjected to support motions can be modeled successfully by using moving support elements. Examples of cantilever and simply-supported beams subjected to support motions are illustrated, and the numerical results are compared with the analytical solutions. The comparison shows good agreement.