• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.6
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• pp.50-59
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• 2015

This study aimed at suggesting Willingness To Pay (WTP) for introduction of the Traffic Accident emergency Call (TAC) system by using Contingent Valuation Method (CVM) which is a general valuation method. As the method, this study suggested a WTP estimation method of the TAC system with the double-bound dichotomous choice model. In previous studies, the data are processed differently according to the type of questions and analysis models used for the calculation of willingness to pay. Therefore, we re-organized the model by the cases using the truncated data sets, and showed the difference in WTPs. The dataset was developed by more than 500 questionnaire obtained from online and offline survey with the consideration of composition ratio by age group referring housing census in 2010 to mitigate regional bias of samples. At last, this study applied various statistical methods, survival analysis, multiple regression, and Tobit model for better interpretation of the questionnaires.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.39 no.5
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• pp.11-20
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• 2002

Based on regularization principles, we propose a new dequantization scheme on DCT-based transform coding for reducing of blocking artifacts and minimizing the quantization error. The conventional image dequantization is simply to multiply the received quantized DCT coefficients by the quantization matrix. Therefore, for each DCT coefficients, we premise that the quantization noise is as large as half quantizer step size (in DCT domain). Our approach is based on basic constraint that quantization error is bounded to ${\pm}$(quantizer spacing/2) and at least there are not high frequency components corresponding to discontinuities across block boundaries of the images. Through regularization, our proposed dequantization scheme, sharply reduces blocking artifacts in decoded images. Our proposed algorithm guarantees that the dequantization process will map the quantized DCT coefficients will be evaluated against the standard JPEG, MPEG-1 and H.263 (with Annex J deblocking filter) decoding process. The experimental results will show visual improvements as well as numerical improvements in terms of the peak-signal-to-noise ratio (PSNR) and the blockiness measure (BM) to be defined.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.1
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• pp.12-17
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• 1993

Growth runs of KTP single crystals were carried out by the hydrothermal method. KTP powders used for the crystal growth were prepared as a single phase by the solid state reaction of a stoichiometric mixture of $KH_2PO_4 and TiO_2$ at TEX>$800^{\circ}C$ and subsequently by the hydrothermal treatment at $250^{\circ}C$ 4m KF solution. The most effective solvents for the crystal growth of KTP were KF and K $K_2HPO_4$ solutions. Solubilities of KTP in these solutions were positive over the range $350~450^{\circ}C$.Seed crystals of good quality could be obtained by the horizontal temperature gradient method at temperatures over the range 380~430^{\circ}C$ in these solutions. The hydrothermal conditions for the high growth rates of seed crystals are as follows: growth method; vertical temperature gradient method, solvent; 4m KF or $K_2HPO_4$ solution, temperature region; $400~450^{\circ}C$, pressure region; $1000~1500kg/cm^2$, where solubility of KTP was large enough to proceed the growth. Under such conditions, seed crystals of KTP are grown at a rate of approximately 0.06-0.08mm/day in the direction of the c-axis. Morphologies of grown crystals tended to be bounded by (100), (011) and (201) faces.

• KSBB Journal
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• v.9 no.3
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• pp.325-331
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• 1994

PGA is formed in a route of CO2 fixation of RuBP catalyzed by RuBPCase, followed by reduction of the PGA by NADH to GAP This reduction is enhanced in an anionic micellar solution(SDS), in which NADH is distributed in the aqueous and the micellar pseudophases in a given ratio. This micellar bounded NADH reacts to PGA, and in higher micellar concentration than $1.25{\times}10^{-2}M$, most of NADH is oxidized to NAD+ by PGA. On the other hand, in the solutions of the positive ionic(CTABr), zwitter ionic(Chaps) and nonionic (Brij and Triton X-100) micelles, the reactions are also enhanced and the concentrations of NADH reach minima with micellar concentrations. Such minima are typical of micellar catalyzed bimolecular reactions, and the fall in concentrations of the reductant followed by a gradual increase is charataristic of reactions of hydrophobic substrates: that is, the reductions of PGA by NADH are sharply enhanced in a range of the lower micellar concentrations, and NADH amounts in ca. $1.25-2.50{\times}10^{-3}M$ micellar solutions are reached to minima, followed by gradual increases of the reductant concentration.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.349-356
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• 2010

Analysis of high-resolution seismic profiles acquired from the southeastern continental shelf of Korea reveals that the late Quaternary transgressive deposits consist of six seismic units created in response to sea-level rise. These units with different seismic facies and geometry can be grouped into two distinct depositional wedges (paralic and marine) bounded by a ravinement surface. The paralic component underlying the ravinement surface consists of the sediment preserved from shoreface erosion and contains incised-channel fill, ancient beach-shoreface deposit and estuarine deposit. The top of paralic unit is truncated by a ravinement surface and overlain by marine component. The marine component consists of the sediment produced through shoreface erosion during landward transgression and contains mid-shelf sand sheet, mid-shelf sand ridge and inner shelf sand sheet. Such transgressive stratigraphic architecture of six sedimentary units is controlled by a function of lateral changes in the balance among rates of relative sea-level rise, sediment input and marine processes at any given time.

• The Journal of the Petrological Society of Korea
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• v.24 no.2
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• pp.125-139
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• 2015

Rock structural and microstructural analyses on the deformed Cheongsan granite, which is characterized by abundant feldspar megacrystals, have been carried out to understand the microstructural change during the mylonitization by ductile shear deformation. In K-feldspars, the characteristic microstructures are recognized as microkinks, microfractures, myrmekites, flame perthites, and core-and-mantle structures without the development of subgrains in outer core-zone. Microkinks are observed in both the microfractured and unmicrofractured K-feldspars and the directions of their axes are generally extended across the adjacent K-feldspar fragments bounded by microfractures. Myrmekites and flame perthites are found on the strain-localized boundaries of the microfractured K-feldspars. In plagiclases, microfractures, deformation twins and kink bands are predominant. Grain size reduction of plagioclase megacrysts also occurs by microfracturing but the core-and-mantle structures like the case of K-feldspars are uncommon in the microfractured plagioclases. The deformation twins, which overlap the igneous zoning structures, are often found in less deformed rocks. The twin lamellae in more deformed rocks generally bisect the obtuse angles of conjugate kink-band boundaries, and are microfractured or microfaulted and randomly oriented. From such characteristic microstructures, thus, it can be suggested that the micostructures during the mylonitzation of Cheongsan granite was developed as follows: production of microkinks in the K-feldspar megacrysts and of deformation twins and kink bands in the plagioclase megacrysts, and then grain-size reduction of the feldspar megacrysts through microfracturing, and then production of core-and-mantle structures (grain-size reduction of the microfractured K-feldspars through grain boundary migration), myrmekites and flame perthites in the microfractured K-feldspars.

• Journal of the Korean Vacuum Society
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• v.19 no.3
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• pp.217-223
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• 2010

We grew multi-stacked InAs/$In_{0.1}Ga_{0.9}As$ DWELL (dot-in-a-well) structure by metal organic chemical vapor deposition and investigated optical properties by photoluminescence and I-V characteristics by dark current measurement. When stacking InAs quantum dots (QDs) with same growth parameter, the size and density of QDs were changed, resulting in the bimodal emission peak. By decreasing the flow rate of TMIn, we achieved the uniform multi-stacked QD structure which had the single emission peak and high PL intensity. As the growth temperature of n-type GaAs top contact layer (TCL) is above $600^{\circ}C$, the PL intensity severely decreased and dark current level increased. At bias of 0.5 V, the activation energy for temperature dependence of dark current decreased from 106 meV to 48 meV with increasing the growth temperature of n-type GaAs TCL from 580 to $650^{\circ}C$. This suggest that the thermal escape of bounded electrons and non-radiative transition become dominant due to the thermal inter-diffusion at the interface between InAs QDs and $In_{0.1}Ga_{0.9}As$ well layer.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.6
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• pp.523-530
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• 2019

For the low-Pt electrodes for polymer electrolyte fuel cells (PEMFCs), the optimization of ionomer content for anode catalyst layers was carried out. A commercial catalyst of 20 wt.% Pt/C was used instead of 50 wt.% Pt/C which is commonly used for PEMFCs. The ionomer content varies from 0.6 to 1.2 based on ionomer to carbon ratio (I/C) and the catalyst layer is formed over the electrolyte by the ultrasonic spray process. Evaluation of the prepared MEA in the unit cell showed that the optimal ionomer content of the air electrode was 0.8 on the I/C basis, while the hydrogen electrode was optimal at the relatively high ionomer content of 1.0. In addition, a large difference in cell performance was observed when the ionomer content of the hydrogen electrode was changed. Increasing the ionomer content from 0.6 to 1.0 by I/C in a hydrogen electrode with 0.05 mg/㎠ platinum loading resulted in more than double cell performance improvements on a 0.6 V. Through the analysis of various electrochemical properties in the single cell, it was assumed that the change in ionomer content of the hydrogen electrode affects the water flow between the hydrogen and air electrodes bounded by the membrane in the cell, which affects the overall performance of the cell. A more specific study will be carried out to understand the water flow mechanism in the future, and this study will show that the optimization process of hydrogen electrode can also be a very important cell design variable for the low-Pt and high-performance MEA.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.4
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• pp.563-568
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• 2007

This paper presents a methodology for predicting nonlinear time series based on the neural network with weighted fuzzy membership functions (NEWFM). The degree of classification intensity is obtained by bounded sum of weighted fuzzy membership functions extracted by NEWFM, then weighted average defuzzification is used for predicting nonlinear time series. The experimental results demonstrate that NEWFM has the classification capability of 92.22% against the target class of GDP. The time series created by NEWFM model has a relatively close approximation to the GDP which is a typical business cycle indicator, and has been proved to be a useful indicator which has the turning point forecasting capability of average 12 months in the peak point and average 6 months in the trough point during 5th to 8th cyclical period. In addition, NEWFM measures the efficiency of the economic indexes by the feature selection and enables the users to forecast with reduced numbers of 7 among 10 leading indexes while improving the classification rate from 90% to 92.22%.

• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.128-136
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• 2015

River areas include channels, floodplains and all the areas affected by physical and ecological processes in river systems. It is noticeably different from present riparian zone which is bounded by dykes. In this study, two methods for delineation of a floodplain are proposed, which are used for evaluation of the function of a river. One of them is a geomorphology-based technique and the other is hydrology-based inundation analysis. For the Mankyung River, these two methods are applied to delineate the floodplain area. Areas delineated with both methods are mutually compared. The results show that the geomorphology-based method is suitable for the delineation of a valley bottom, including the floodplain in a broader sense, which is unlike an inundated area reflecting contemporary hydrologic conditions. Compared with other flood frequency areas, a 100-year flood inundation area was found reasonable to represent the spatial extent of a floodplain without regard to the longitudinal location along a river. However, it is necessary in certain rivers reach where the division of a channel exists to compare a geomorphological analysis on a valley bottom with an inundation area of different frequencies.