• Journal of The Korean Association of Information Education
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• v.11 no.4
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• pp.505-515
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• 2007

The purpose of this study is to develop a web based system with six thinking hats techniques for effective debate learning. For this study, first, design strategics of six thinking hats techniques were drawn out in oder to apply the ideas onto the web. second, a prototype was drafted for the model development. Third, a web based debate learning system was developed with six thinking hats techniques concentrated. The developed system was corrected and revised by educational technology experts and teachers with focus group interview, triangulation and member checking methods. This system could be an useful device for 1) activating participants' vigorous interaction, 2) overcoming time and place restriction, 3) especially constructing a progressive debate process with the subject of a real life and 4) designing courses for various and effective debate progress.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.139-139
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• 2010

Ionic Transition Metal Complex based (iTMC) Light-emitting electrochemical cells (LEECs) have been drawn attention for cheap and easy-to-fabricate light-emitting device. LEEC is one of the promising candidate for next generation display and solid-state lighting applications which can cover the defects of current commercial OLEDs like complicated fabrication process and strong work-function dependent sturucture. We have investigated the performance characteristics of LEECs based on poly (3, 4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS)-incorporated transition metal complex, which is tris(2, 2'-bipyridyl)ruthenium(II) hexafluorophosphate in this study. There are advantages using conductive polymer-incorporated luminous layer to prevent light disturbance and absorbance while light-emitting process between light-emitting layer and transparent electrode like ITO. The devices were fabricated as sandwiched structure and light-emitting layer was deposited approximately 40nm thickness by spin coating and aluminum electrode was deposited using thermal evaporation process under the vacuum condition (10-3Pa). Current density and light intensity were measured using optical spectrometer, and surface morphology changes of the luminous layer were observed using XRD and AFM varying contents of PEDOT:PSS in the Ruthenium(II) complex solution. To observe enhanced ionic conductivity of PEDOT:PSS and luminous layer, space-charge-limited-currents model was introduced and it showed that the performances and stability of LEECs were improved. Main discussions are the followings. First, relationship between film thickness and performance characteristics of device was considered. Secondly, light-emitting behavior when PEDOT:PSS layer on the ITO, as a buffer, was introduced to iTMC LEECs. Finally, electrical properties including carrier mobility, current density-voltage, light intensity-voltage, response time and turn-on voltages were investigated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.7118-7125
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• 2015

This study examined one of the concerned or even imperative issues in the field of contemporary finance related to approaching an optimal level of cash holdings for the firms belonging to the chaebols in the Korean domestic capital markets. However, the subject may not have been drawn much attention so far, even if there are still ongoing and active debates among the interest parties at the macro- or micro-level. Two primary hypotheses were postulated to be empirically tested. On the results of the first hypothesis test for the existence of an optimal cash reserves for the sample firms, two estimation techniques were performed in terms of a quadratic regression equation and a relationship between a firm's value and the residuals derived from the static panel date model. As a primary financial implication of the study which may contribute to the practitioners and the academics in finance, the optimal level of cash holdings can be estimated by controlling for the a priori significant components for the sample firms towards maximizing firm value.

• The Korean Journal of Financial Management
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• v.21 no.1
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• pp.125-148
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• 2004

This paper deals with the relationship between money supply and the stock market. However, unlike past works, it has employed a rational expectation hypothesis and an efficient market hypothesis drawn from new classical macroeconomics and new Keynesian macro-economics, respectively. Accordingly, hypothesis 1 states that if economic subjects have rational expectation, they will immediately respond to a change in money supply. On the other hand, hypothesis 2 supposes that the expectation of economic subjects has changed after the currency crisis. This paper has first identified unit root by using the augmented Dickey-Fuller test and the Phillips-Perron test, then testing both hypotheses by employing the Johansen Procedure and vector error correction model for the periods before and after a currency crisis.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.4
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• pp.519-524
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• 2009

Recently, reinforcement learning methods have drawn much interests in the area of machine learning. Dominant approaches in researches for the reinforcement learning include the value-function approach, the policy search approach, and the actor-critic approach, among which pertinent to this paper are algorithms studied for problems with continuous states and continuous actions along the line of the actor-critic strategy. In particular, this paper focuses on presenting a method combining the so-called ACFRL(actor-critic fuzzy reinforcement learning), which is an actor-critic type reinforcement learning based on fuzzy theory, together with the RLS-NAC which is based on the RLS filters and natural actor-critic methods. The presented method is applied to a control problem for crawling robots, and some results are reported from comparison of learning performance.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.2
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• pp.145-153
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• 2009

This research utilized the manual to calculate the structural scale of stone and gabion, which was developed through comparison and verification of the results drawn by hydraulic model experiment and existing empirical formula. Appropriate structural scale of stone according to the construction site when the critical velocity was exceeded, utilizing the previously expected and recorded data on current velocity per day and per hour during the final closure period for Saemangeum sea dike. Also, the scale of rocks was presented, considering the altercation in water depth according to the construction. The developed manual offered appropriate rate of mixed use of stone and gabion that suits various flow velocities, which will minimize any loss of stone-gabion and contribute to successful final closure, and proved the utility and application of the manual.

• Journal of Digital Convergence
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• v.15 no.3
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• pp.211-219
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• 2017

Among government projects for reduction of coastal disaster, coastal maintenance project stage 1(2000~2009) and stage 2(2010~2019) to reduce coastal erosion and sedimentation are currently under process. In performing the coastal maintenance projects, it is necessary to install artificial concrete armor units for coastal protection. Presently in Korea, products manufactured in Japan are applied to the site, or blocks self-developed by the construction firms are installed. However, there is a lack of technical reviews such as verification of hydraulic characteristics, securing the stability and design techniques. This study is intended to develop waterfront shore protection blocks with good accessibility of people and excellent coastal disaster reduction and protection capability. Through this study, hydraulic characteristics and stability coefficients of shore protection blocks could be drawn.

• Fashion & Textile Research Journal
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• v.6 no.6
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• pp.810-814
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• 2004

This study is one of the fundamental researches for the development of future smart clothing and textile products using silver(Ag) nano powder. Our study was focused on the blocking or insulating effects of nano-processed textiles from electromagnetic waves. Also, for the surveying of the actual effect to human body, we measure the variation of electroencephalogram which is an indication of human physical symptoms. Among various textiles in this experiment, nano silver processed case has shown the best blocking performance from the electromagnetic waves, which decreases depending on the distance. As a reference model of working environment, we setup the visual stimuli object on the computer that is a source of electromagnetic wave. The power spectrum distribution and the incidence of electroencephalogram was measured. The analysed data has shown that, with nano-processed textiles, ${\beta}$ wave does not appear very often where ${\beta}$ wave appears only to illustrate the stable states of human's body. However, as for the materials without nano processing, the ratio of ${\gamma}$ waves in the total level of electroencephalogram becomes higher in spite of short exposure to visual stimuli in work environment, which shows that the worker becomes stressed. The ${\beta}$ wave electroencephalogram of all materials is drawn in calcarine fissure of occipital lobe to show the convergent distribution, and stronger with block-processed Nano Silver Silk(NSS). The study based on the potential risks of human diseases such as physical fatigue by electromagnetic waves, and has shown that the application of Nano Silver textile for human uses require a proper particle size of it which would not penetrate cellular tissues, and a proper binder and binding treatment for it. However, it is highly required for back-up researches to verify various aspects in applying nano silver to textile products.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.191-197
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• 1998

Discriminant analysis using near infrared spectra derived from Korean Flue-cured(KF) and American Flue-cured(AF), and also Korean Burley(KB) and American Burley(AB) tobacco was done to classify flue-cured and burley tobacco as either grown in Korea or grown in the USA. Samples were scanned in the wavelength of 400 ～ 2500 nm by near infrared analyzer(NIRSystem Co., model 6500). The discrimination equations for flue-cured and burley tobacco were developed using partial least square 2 method in Infrasoft International NIRS 3 software package. KF samples used for the development of the discrimination equations were higher contents of total sugar, crude ash and chlorine, and higher value of leaf density and brightness, but lower contents of nicotine, total nitrogen and ether extracts, and higher value of redness than those of AF samples. KB samples were higher contents of nicotine, crude ash and chlorine, but lower contents of ether extracts and value of brightness than those of AB samples. On 3 dimensional graph drawn with 3 principal component scores calculated with 3 principal component from KF and KB sample spectra, KF sample spectra were significantly different from AF, and also KB sample spectra were significantly different from AB. The discrimination equations of flue-cured and burley were developed with 3 principal component, respectively. The discrimination equations for flue-cured and burley had a standard error of 0.03 and 0.04, and a R2 of 0.88 and 0.84, respectively. The tobacco samples used for the development of discrimination equation were perfectly classified as KF and AF by flue-cured discrimination equation, and also perfectly classified KB and AB by burley discrimination equation, respectively. The correct classification rates of KF and AF samples not used for the development of discrimination equations were 9S % (828 out of 869 samples) and 98 % (98 out of 100 samples) by flue-cured discrimination equations, and KB and AB samples were 94%(345 out of 368 samples) and 100%(42 out of 42 samples) by burley discrimination equations, respectively.

• Journal of Korea Spatial Information System Society
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• v.11 no.4
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• pp.33-38
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• 2009

Since the beginning of 2000, the ubiquitous technology rapidly has been at center of public concerns, and application of the ubiquitous technology is expanding in Korea with U-City as the center. U-City is currently planned and built by local governments, but the applicable range of the ubiquitous technology should be expanded in the future to build U-Territory and U-Land projects. As a part of this, U-forest should also be implemented, and that now is the time to gain support in policy and systematic initiative. Therefore, this study defines U-Forest concept to implement valuable national resources, healthy land environment, and pleasant green space by using ubiquitous technology as an effective way to produce, manage, use, and distribute the forest. In order to establish strategy for U-Forest, it has considered basic forest plan, k-Forest, and FGIS projects, and has drawn a service model pertaining to them. Also, it has proposed the need to establish the basic plan for U-Forest, and suggested details to include in the plan.