• Journal of Korea Water Resources Association
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• v.53 no.11
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• pp.985-997
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• 2020

SWAT (Soil and Water Assessment Tool)-MODFLOW (Modular Groundwater Flow) is a coupled model that linking semi-distributed watershed hydrology with fully-distributed groundwater behavior. In this study, the groundwater simulation results of SWAT and SWAT-MODFLOW were compared for Bokhacheon watershed in Namhan river basin. The models were calibrated and validated with 9 years (2009~2017) daily streamflow (Q) data of Heungcheon (HC) water level gauge station and the daily groundwater level observation data of Yulheon (YH). For SWAT, the groundwater parameters of GW_DELAY, GWQMN, and ALPHA_BF affecting baseflow and recession phase were treated. The SWAT results showed the coefficient of determination (R²) of 0.7 and Nash-Sutcliffe model efficiencies (NES_Q, NSE_inQ) for Q and 1/Q with 0.73 and -0.1 respectively. For SWAT-MODFLOW, the spatio-temporal aquifer hydraulic conductivity (K, m/day), specific storage (S_s, 1/m), and specific yield (S_y) were applied. The SWAT-MODFLOW showed R², NSE_Q, and NSE_inQ of 0.69, 0.74, and 0.51 respectively. The SWAT-MODFLOW considerably enhanced the low flow simulation with the help of aquifer physical information. The total streamflow of SWAT and SWAT-MODFLOW were 718.6 mm and 854.9 mm occupying baseflow of 342.9 mm and 423.5 mm respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1076-1084
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• 2006

In this paper, we first review a concept of hybrid division duplexing (HDD) scheme, which has been proposed as a new type of duplexing scheme useful for a next generation mobile communication system and its implementation issues, including the unified radio resource management for HDD scheme. The HDD scheme maintains the advantages of both TDD and FDD at the same time while providing a useful structure to control the inter-cell interference, caused by an asymmetric traffic load of multimedia services over uplink and downlink in the TDD scheme. Employing two frequency bands, one for TDD scheme and the other for FDD scheme, uplink is operating under the TDD scheme only, while downlink is operating under the TDD or FDD scheme, depending on the location of mobile station. In the HDD scheme, therefore, it must determine a type of duplexing scheme to employ in the downlink and futhermore, a ratio of uplink and downlink duration to meet a given traffic load of asymmetric service, which requires some unified radio resource management for handling the subsequent inter-cell interference. In this paper, we propose a distributed adaptive control approach as a means of unified radio resource management for a HDD system that maximizes the overall system efficiency by fully utilizing the resource in TDD band, while minimizing the inter-cell interference.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.10
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• pp.1487-1494
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• 2010

Structured lipid (SL) for cocoa butter alternative was synthesized by interesterification of coconut oil fraction and palm stearin (6:4 and 8:2, by weight) in a shaking water bath at $60^{\circ}C$ and 180 rpm. It was performed for various reaction times (1, 2, 3, and 6 hr). The reaction was catalyzed by sn-1,3 specific Lipozyme TLIM (immobilized lipase from Thermomyces lanuginosus). SL-solid part was obtained from acetone fractionation at $0^{\circ}C$. SL-solid part was blended with other palm oils and fractions for desirable property of cocoa butter alternative (SL-solid part : palm middle fraction : palm stearin solid : palm oil, 70.4:18.4:2.9:8.3, by weight). In reversed-phase HPLC analysis, triacylglycerol species of cocoa butter alternative had partition number of 40 (10.77%), 42 (13.06%), 44~46 (17.38%) and 48 (51.88%). Major fatty acids of cocoa butter alternative were lauric acid (16.5%), myristic acid (12.28%), palmitic acid (46.03%), and linoleic acid (14.75%). Solid fat content (SFC) and polymorphic form (${\beta}'$ form) of cocoa butter alternative prepared were similar to those of commercial cocoa butter replacer (CBR).

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.1
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• pp.25-33
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• 2016

In order to visualize point based Location-Based Social Network Services(LBSNS) data on multi-scaled tile map effectively, it is necessary to apply tile-based clustering method. Then determinating reasonable numbers and size of tiles is required. However, there is no such criteria and the numbers and size of tiles are modified based on data type and the purpose of analysis. In other words, researchers' subjectivity is always involved in this type of study. This is when Modifiable Areal Unit Problem(MAUP) occurs, that affects the results of analysis. Among LBSNS, geotagged Twitter data were chosen to find the influence of MAUP in scale effects perspective. For this purpose, the degree of spatial autocorrelation using spatial error model was altered, and change of distributions was analyzed using Morna's I. As a result, positive spatial autocorrelation showed in the original data and the spatial autocorrelation was decreased as the value of spatial autoregressive coefficient was increasing. Therefore, the intensity of the spatial autocorrelation of Twitter data was adjusted to five levels, and for each level, nine different size of grid was created. For each level and different grid sizes, Moran's I was calculated. It was found that the spatial autocorrelation was increased when the aggregation level was being increased and decreased in a certainpoint. Another tendency was found that the scale effect of MAUP was decreased when the spatial autocorrelation was high.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.443-449
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• 2015

In this paper, we proposed Channel allocation scheme according to the user's location with IR. In VLC System, LED can generate various colors of light by controlling the mixing ratio of each individual RGB color element. Thus, each RGB channel will have a different signal power, and each channel will have different performance. This proposed system using Visible light(RGB) as way to transmit signals, it depends on the mixture RGB, which decided the color of light, moreover, each things determined their performance. However, if the signal were fixed allocated RGB to transmit such as the original system, the importance of the each signals a different occur the limit on the quality of signals. To solve this problem in this paper, according to the RGB mixture ratios analyze the performance for the LED, which analyzed based on allocating the signal by transmitting to improve the quality was about how researched. In addition, our proposed system is able to improve the performance of BER and satisfied the Qos to desire users.

• Korean Journal of Optics and Photonics
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• v.9 no.5
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• pp.277-281
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• 1998

One dimensional inhomogeneous aperture modulation effects on the MTF of optical system was investigated. The lens under test was a doublet made in Korea. It has 10 mm effective diameter, 87.8 mm effective focal length. The ray-fans and spot diagrams were calculated and presented on the picture for on-axis and off-axis (field of view, $1^{\circ}$ and $2^{\circ}$). Aperture modulation was carried out by positioning a aperture modulator close contacter with the lens under test. We bought two modulators from Edmud Company in U.S.A. One was linear type and the other was stepped type. The MTFs were measured on the best of focus for each modulated aperture where the MTF has the highest value for 60 line/mm and were compared with one another. For on-axis, the MTFs of some modulated apertures had higher values than the MTF of unmodulated aperture in the high frequency region. In the case of off-axis, at the field of view $1^{\circ}$, the MTF values of some modulated aperture are improved prominently and some other one are disimproved. At the field of view $2^{\circ}$ most of the MTFs of modulated apertures had lower values than the MTF of unmodulated aperture except the MTFs of linear and inverse linear type aperture in the high frequency area. But the values of MTFs in high frequency region were too low for actual use.

• Journal of Korea Water Resources Association
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• v.51 no.1
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• pp.35-48
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• 2018

Groynes are installed generally to protect the riverside or the river bank from the erosion caused by water flows by controlling the flow direction and velocity in rivers. In the past, groynes were used to secure enough depth of water in canals. As there has been a growing interest in river restoration and the natural river maintenance since 2000, groynes are proposed as a major environmental hydraulic structure because the flow control and various river bed conditions around the groyne can contribute to habitat functions. Groynes are typically installed in a series. In designing groyne series, groyne spacing is an important factor because the flow changes in the main canal and the flow inside the groyne area occurs variably depending on the groyne spacing. This study provide information to determine the groyne spacing suitable for the purpose of the groyne by examining the flows that variably changes according to the groyne spacing and angle in the recirculation zone of the groyne field. In particular, the formation of vortex, the location of vortex core and the water flow near the river bank, all of which occur in the recirculation zone inside the groyne area, were mainly analyzed to examine the flow characteristics near the river bank that influences the safety of the river bank area. The results of the experiment will serve as important basic data to examine changes in the river bed inside the groyne area as well as the safety of river banks following the installation of groyne series.

• Membrane Journal
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• v.12 no.1
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• pp.41-50
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• 2002

The streaming potential generated by the electrokinetic flow within electric double layer of charged microchannel is applied to determine the zeta potential of hollow-fiber membrane pore by using the general Helmholtz-Smoluchowski equation. The streaming potential is know to provide a useful real-time information on the surface property and the interaction between pore and particles in actual situations and physicochemical conditions. The influence of physicochemical parameters upon the filtration with hollow-fibers has been examined with an in-situ and simultaneously monitoring the streaming potential as well as permeate flux. In particular, the present study examined an experimental method to identify the effect of cake layer which can vary according to the axial position of a hollow-fiber and the progress of membrane fouling by measuring the position-dependent streaming potential. As the latex concentration increases, the permeate flux decreased but the streaming potential increased. The growth of cake layer has been mire developed with increasing latex concentration, however, the effect of surface charges of latexes deposited on the membrane surface leads to increase the streaming potential. With increasing ionic concentration of KCI, both the permeate flux and the streaming potential decrease. The increase of ionic concentration provides a compact cake layer due to the shrinkage of Debye length and the decreased streaming potential results from the weakened ionic flows owing to a thin diffusive double layer.

• Journal of Wetlands Research
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• v.8 no.3
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• pp.67-77
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• 2006

Sedimentological investigations on surface and suspended sediments were performed in Masan Bay of the South Sea in order to reveal recent changes in depositional environments concerning anthropogenic influence. Surface sediments had been classified as 3 sediment facies: mud, slightly gravelly mud, and gravelly mud. In general, mud facies with more than 60% of silt is predominant and slightly gravelly mud facies occurs at the watercourse of bay's central area. The silt-dominant mud faices appears to be predominant before and after dredging. Temperature and salinity changes during one tidal cycle for each season suggest that water columns were stratified without vertical mixing regardless of the season due to weak intensity of tide from the effect of geographical features. The effect of freshwater discharge from the land seems to be insignificant. The strongest current was observed during ebb tide in spring and autumn while observed during flood tide in summer and winter. Net sediment flux (fs) and net suspended sediment transport (Qs) for suspended sediment were determined by remaining drift developed here. Net suspended sediment transport loads were seaward with $62.02{\times}10^3kgm^{-1}$, $31.84{\times}10^3kgm^{-1}$ in spring and fall, respectively, and landward with $18.23{\times}10^3kgm^{-1}$, $3.22{\times}10^3kgm^{-1}$ in summer and winter, respectively.

• Korean Journal of Microbiology
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• v.41 no.4
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• pp.293-299
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• 2005

Many isolates from soil of Korean ginseng rhizosphere did not show remarkable growth on full strength of the conventional nutrient broth (NB medium) but grew on its 100-fold dilution (DNB medium). Six hundred-forty strains were isolated as oligotrophic bacteria. In the course of screening for new bioactive compounds from oligotrophic bacteria from soil, 8 strains which had appeared to form of clear zone on a medium containing colloidal chitin as a sole carbon source were selected for further studies. Strain CR42 hydrolyzed a fluorogenic analogue of chitin, 4-methylumbelliferyl-D-glucosaminide (MUF-NAG) . Mo st of the culture supernatant of these isolates hydrolyzed 4-methylumbelliferyl-D-N,N'-diacetylchitobioside (MUF-diNAG). The isolates were heterogeneous and categorized to gamma- and beta-proteobacteria, Bacillaceae, Actinobactepia, and Bacteroides by 16S rRNA analysis. Two strains, WR164 and CR18, had a 16S rRNA sequence of $95-96\%$ identical to uncultured bacteria. It was observed that CR2 and CR75 could inhibit the growth of Colletotrichum gloeosporioides with hyphal extention-inhibition assay on PDA plate supplemented with $1\%$ colloidal chitin.