• Korean Journal of Remote Sensing
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• v.34 no.2_2
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• pp.431-437
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• 2018

We analyzed the feasibility of detecting wave gliders moving on the sea surface using SAR images. For the experiment, a model was constructed and placed on the sea using a towing ship before and after the satellite observation time. In the acquisition of KOMPSAT-5 image, high resolution SAR data of spotlight mode was collected considering the small size of wave glider. As a result of the backscattering intensity analysis around the towing ship along with wave glider, several scattering points away from the ship were observed, which are not strong but clearly distinguished from the surrounding clutter values. Considering the distance from the center of the ship, it seems to be a signal by the wave glider. On the other hand, it is confirmed that the wave glider can be detected even at the very low false alarm rate ($10^{-6}$) of the target detection using CFAR. Although the scatter signal by the wave glider could be distinguished from the surrounding ocean clutter in the high resolution SAR image, further research is needed to determine if actual wave gliders are detected in various marine environments.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.2
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• pp.272-277
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• 2010

This experimental study was performed to investigate the antitumor effect of Egg white combined-Chalcanthite (InSan 4, IS4) in xenografted nude mice with NCI-H460 human lung cancer cell. We cultured NCI-H460 cell lines and xenografted them on nude mice. These mice were divided into 3 groups; group with dose of 45 mg/kg IS4 orally, group with dose of 90 mg/kg IS4 orally, and the control group. They had been raised and treated for 28 days. We checked their body weight, tumor weight and volume twice a week, and their absolute organ weight, microhistological observation and biochemical blood analysis at the final day by sacrificing them. We also calculated their tumor inhibition rate (IR), mean survival time and percent increase in life span (% ILS). In this study, we observed that all of the IS4 treated mice have tumor regression, dosage-dependently, compared to the control group. Tumor weight and volume of high dose treated mice were smallest. IR increased in IS4 in a dose-dependent manner. Mean survival time and percent increase in life span (% ILS) in high-dose IS4 treatment group were the highest of the three groups. There was no significant difference in biochemical blood analysis, alanine phopsphatase (ALP), Calcium, creatinine (CRE), alanine transferase (ALT), and aspartate transaminase (AST) levels. The urea nitrogen (UN) level results significantly decreased by IS4 45 and 90 mg/kg (IS4 45 mg/kg, IS4 90 mg/kg, p<0.01). IS4 may have potential anti-tumor effect in a solid tumor induced by NCI-H460 without remarkable side effects.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.8
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• pp.757-764
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• 2015

Mathematical modeling of focal plane compensation device in the small earth-observation satellite camera has been conducted experimently for compensation of micro-vibration disturbance. The PZT actuators are used as control actuators for compensation device. It is quite difficult to build up mathematical model because of hysteresis characteristic of PZT actuators. Therefore, the compensation device system is assumed as a $2^{nd}$ order linear system and modeled by using MATLAB System Identification Toolbox. It has been found that four linear models of compensation device are needed to meet 10% error in the input frequency range of 0~50Hz. These models describe accurately the dynamics of compensation device in the 4 divided domains of the input frequency range of 0~50Hz, respectively. Micro-vibration disturbance can be compensated by feedback control strategy of switching four models appropriately according to the input frequency.

• Applied Microscopy
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• v.27 no.4
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• pp.433-452
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• 1997

Mongolian gerbil (Meriones unguiculatus) has been as an animal model for studing the neurological diseases such as stroke and epilepsy because of the congenital incompleteries in Willis circle, as well as the investigation of water metabolism because of the long time-survival in the condition of water-deprived desert condition, compared with other species animals. In order to accomplish the this research, first of all another divided the laboratory animals 5 groups of which each group include the 5 animals. In this study were investigated the histological structure in the kidney, measured the plasma osmolalities at the time of sacrifice of indivisual animals, and the body weights every day during water-deprived. The results obtained in this study were summarized as followings: 1. The body weights and decreasing rates of the body weight in water-deprived mongolian gerbil groups were continuosly decreased. 2. The plasma osmolalities were increased from the 5th water-deprived day, after then the gradually increasing reached nearly its equilibrium state at the 10th water-deprived day. 3. The urine volumes were abruptly decreased from the 2th water-deprived day, after then the gradually decreasing patterns were reached nearly its equilibrium state at the 10th day, and stopped the 11th day. 4. In the light microscopical observation of the kidney, glomerular capillary loop thickening, mesangial matrix increasing, sclerosis, glomerular cystic atrophy, interstitial fibrosis, tubular dilatation, mononuclear interstitial inflammation, interstitial mineralization, and hyperplasia of the collecting duct epithelium in the cortex area, were observed from the 10th water deprived day, and the lesions were gradually severe changed as the time lapse. 5. In the electron microscopical findings of the kidney, the degenerative changes of endothelial cell, podocyte and mesangial cell in glomeruli were initially observed on the 10th water-deprived day as well as the degeneration of microvilli and intracellular organelle in the renal tubules.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.11-19
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• 2014

This study is analyze future climate and land cover change affects behaviors for amount of streamflow and sediment discharge within basin. We used the climate forecast data in RCP 4.5 and 8.5 (2011-2100) which is opposite view for each other among RCP scenarios that are discussed for 5th report for IPCC. Land cover map built based on a social economic storyline in RCP 4.5/8.5 using Logistic Regression model. In this study we set three scenarios: one scenario for climate change only, one for land cover change only, one for Last both climate change and land cover change. It simulated amount of streamflow and sediment discharge and the result showed a very definite change in the seasonal variation both of them. For climate change, spring and winter increased the amount of streamflow while summer and fall decreased them. Sediment showed the same pattern of change steamflow. Land cover change increases the amount of streamflow while it decreases the amount of sediment discharge, which is believed to be caused by increase of impervious Surface due to urbanization. Although land cover change less affects the amount of streamflow than climate change, it may maximize problems related to the amount of streamflow caused by climate change. Therefore, it's required to address potential influence from climate change for effective water resource management and prepare suitable measurement for water resource.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.4
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• pp.232-237
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• 2010

While global solar radiation is an essential input variable in crop models, the observation stations are relatively sparse compared with other meteorological elements. Instead of using measured solar radiation, the Angstrom-Prescott model estimates have been widely used. Monthly data for solar radiation and sunshine duration are a convenient basis for deriving Angstrom-Prescott coefficients (a, b), but it is uncertain whether daily solar radiation could be estimated with a sufficient accuracy by the monthly data - derived coefficients. We derived the Angstrom-Prescott coefficients from the 25 years observed global solar radiation and sunshine duration data at 18 locations across South Korea. In order to figure out any improvements in estimating daily solar radiation by replacing monthly data with daily data, the coefficients (a, b) for each month were derived separately from daily data and monthly data. Local coefficients for eight validation sites were extracted from the spatially interpolated maps of the coefficients and used to estimate daily solar radiation from September 2008 to August 2009 when, pyranometers were operated at the same sites for validation purpose. Comparison with the measured radiation showed a better performance of the daily data - derived coefficients in estimating daily global solar radiation than the monthly data - derived coefficients, showing 9.3% decrease in the root mean square error (RMSE).

• The Journal of the Korea Contents Association
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• v.15 no.3
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• pp.488-498
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• 2015

Form the observation that the successful management and operation of university websites brings about university branding effects, this paper attempts to identify the problems in relation to evaluation elements of university homepages and establish a new evaluation model that allows us to grasp the importance and priority of phased evaluation elements. In particular, we tried to secure the objectivity of the importance of department homepage evaluation elements by using AHP(Analytic Hierarchy Process). Our analysis shows that among 29 evaluation elements of department homepage, mobile service, curriculum, description of department's characteristics, guide to homepage usage/accessibility to site map and differentiated educational method were considered to be relatively important whereas the relative importance of department's slogan, differentiated image and identity, linkage to SNS, Q&A bulletin board, operation of department community, and FAQ was low. Based on the findings from our analysis, we present the basic foundation for successful management and operation of university department homepages along with a few suggestions for vitalizing those hompages.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.6
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• pp.397-406
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• 2003

The purpose of this study was to observe the titanium implant osseointegration in the osteoporosis-induced animal model. Seventy rats, 11 weeks of age, were divided into two groups : an ovariectomized group and a control group. Titanium screw implants(diameter, 2.0mm; length, 3.5mm) were placed into left tibias of 70 rats, 35 in the control group and 35 in the experimental group. The rats were sacrificed at different time interval (1, 2, 3, 4, 6, 8, and 12 weeks after implantation) for histopathologic observation, histomorphometric analysis and immunohistochemistry with fibronectin and CD34 antibody. The results obtained from this study were as follows: 1. Histopathologically findings, newly formed bone was seen at 3 weeks and became lamellar bone at 8 weeks, and mature trabecullar bone was seen at 12 weeks control group. In experimental group, thickness of regenerated bone increased till 8 weeks gradually and mature trabecullar bone was seen at 12 weeks. 2. By histomorphometric analysis, marrow bone density and contact ratio of marrow bone to implant decreased significantly from 8 to 12 weeks in experimental group compared to control group and also total bone to implant contact ratio decreased significantly from 8 to 12 weeks in experimental group. 3. Fibronectin immunoreactivity was strong at 3 weeks control group and reduced after 8weeks gradually. But it was continuously strong from 3 to 8 weeks in experimental group. 4. CD34 immunoreactivity was very strong in the newly formed osteoblasts from 3 to 8 weeks control group. But it reacted minimally later. While in experimental group, it reacted continuously strong from 3 to 12 weeks. The results of this study suggest that osteoporosis is not an absolute contraindication to dental implantation if sufficient period suggested after fixture installation till second stage surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.131-138
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• 2007

The purpose of this study was to observe the effect of calcium and vitamin D to the titanium implant osseointegration in animal model. 32 rats, 10 weeks of age, were divided into two group: additional calcium and vitamin D supplementation group and a control group. Titanium screw implant(diameter, 2.0mm; length, 3.5mm; pitch-height 0.4mm) were placed into tibia of 32 rats, 16 in the control group and 16 in the experimental group. The rats were sacrificed at different time interval(1, 2, 4, and 8 weeks after implantation) for histopathologic observation, histomorphometric analysis and immunohistochemistry with osteocalcin and osteopontin antibody. Histopathologically findings, newly formed bone was seen at 1 weeks and became lamellar bone at 2 weeks, and mature trabecullar bone was seen at 4 weeks experimental group. In control group, thickness of regenerated bone increased till 4 weeks gradually and trabecullar bone was seen at 8 weeks. By histomorphometric analysis, bone marrow density was increased significantly at 1 and 2 weeks in experimental group compared to control group. Osteocalcin immunoreactivity was strong at 1 week experimental group and reduced after 4 weeks gradually. But it was continuously weakly from 1 to 4 weeks in control group. Osteopontin immunoreactivity was very strong in newly formed bone from 2 to 8 weeks experimental group. And the amount of osteopontin expression was more abundant in experimental group. The results of this study suggest that calcium and vitamin D supplementation promotes bone healing around dental implants

• Journal of the Korean Geophysical Society
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• v.10 no.1
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• pp.1-12
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• 2007

A method to quickly estimate broadband moment magnitudes (Mwp) to warn regional and teleseismic tsunamigenic earthquakes is tested for application of the method to the different seismic observation environment. In this study, the Mwp is calculated by integrating far-field P-wave or pP-wave of vertical component of displacement seismograms in time domain from earthquakes, having magnitude greater than 5.0 and occurred in and around the Korean peninsula from 2000 to 2006. We carefully set up the size of the time window for the computations to exclude S wave phases and other phases following after the P wave phase. The P wave velocities and the densities from the averaged Korean crustal model are used in the computations. Instrumental correction was performed to remove dependency on the seismograph. The Mwp after the instrumental correction is about 0.1 greater than the Mwp before the correction. The comparison of our results to the those of foreign agencies such as JMA and Havard CMT catalogues shows a higher degree of similarity. Thus our results provide an effective tool to estimate the earthquake size, as well as to issue the necessary information to a tsunami warning system when the effective earthquake occurs around the peninsula.