• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.538-545
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• 2001

In this paper a gearless drive system using a permanent-maget synchronous motor for high speed elevators is addressed. The application of permanent magnet synchronous motor to an elevator traction machine enables several improvements including higher efficiency better ride comfort smaller size and lighter weight and so on A PWM boost converter has been also adopted so that DC-link voltage regulation bi-directional power flow and controllable power factor with reduced input current harmonics are possible. To increase the reliability and performance of overall control system the unified control board which can include the car and group controller as well as PWN converter/inverter controller has been designed based on a DSP TMS320VV33. In addition the dynamic load simulator system has been developed so that the drive system of high speed elevator can be tested and evaluated without and limitation on ride distance. Some experimental results are given to verify the effectiveness of the developed system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.121-126
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• 2004

This paper presents an SAR-data calibration technique using a well-calibrated scatterometer. At first a fully-polarimetric antenna pattern(magnitude and phase) of the antenna main-beam using a conducting sphere was measured. Then, this data were used to calibrate polarimetrically an auto-mounted network analyzer-based scatterometer system. This scatterometer system can be used to measure the accurate Mueller matrices of earth surfaces such as grass fields, rice fields and bare soil surfaces; i.e., the phase-difference parameters can be obtained as well as the radar scattering coefficients. If a polarimetrically calibrated scatterometer is operated at the same time with the SAR system, the scatterometer data can be used to correct the SAR data, especially the phase-difference parameters. It was found that the correction effect is remarkable for the degree of correlation ${\alpha}$, which is one of the phase-difference parameter, while the correction effect is negligible for the magnitude parameters(backscattering coefficients).

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.91-98
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• 2009

Infectious bursal disease (IBD) caused by the infectious bursal disease virus (IBDV) has an important economic impact on the poultry industry worldwide. This study examined the adjuvant effects of a plasmid encoding chicken interleukin-6 (pcDNA-ChIL-6) and levamisole (LMS) on in ovo prime-boost vaccination using a genetic vaccine (pcDNA-VP243) to prime in chicken followed by a killed-vaccine boost. A pcDNA-VP243 was injected into the amniotic sac alone or in combination with a pcDNA-ChIL-6 or LMS at embryonation day 18, followed by an intramuscular injection of killed IBD vaccine at 1 week of age. The chicken were orally challenged with very virulent IBDV (vvIBDV) strain at 3 weeks of age and observed for 10 days. No mortality was observed in the groups that received the pcDNA-VP243 alone and pcDNA-VP243 plus pcDNA-ChIL-6 or LMS compared to 100% mortality in unvaccinated challenge control group. However, as determined by bursal damage (the presence of IBDV RNA, B/B ratio, and lesion score), a pcDNA-VP243 alone group was superior to pcDNA-VP243 plus pcDNA-ChIL-6 or LMS groups in the protection against post-challenge. These findings suggest that in ovo priming with genetic vaccine and boosting with killed vaccine is an effective strategy for protecting chicken against vvIBDV and the addition of pcDNA-ChIL-6 or LMS did not enhance protective immunity.

• Tuberculosis and Respiratory Diseases
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• v.51 no.6
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• pp.540-549
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• 2001

Background : Usual interstitial pneumonia (UIP) is a progressive fibrous lung disease with occasional fatal outcomes. However, the extent and rate of progression varies markedly from one patient to another. As a result, it is difficult to determine the time of the initial treatment and assess the disease activity and course. Fibroblast foci (FF) is well known to synthesize collagen actively by their myofibroblasts component. However, the prognostic value of the FF have not been evaluated in patients with VIP. Therefore this study was undertaken to determine how the number of fibroblastic foci can reflect the disease activity and progression. Methods: Twenty patients with UIP(M : F=13 : 7), who were diagnosed by a surgical lung biopsy. The number of fibroblastic foci was analyzed in terms of its correlation with the clinical manifostations, pulmonary function test, arterial blood gas analysis, and a bronchoalveolar lavage(BAL). Results : The number of fibroblastic foci did not correlate with the various lung function tests and the other clinical parameters. Interestingly, the percentage of neutrophils in the bronchoalveolar lavage fluid did correlate with the quantity of the normalized Vv of FF(r=0.60, p<0.05). The patients were divided into 2 groups, group I and II, arbitrarily, according to the value of the normalized Vv. The clinical parameters and the PIT results were not different between the two groups. In particular, the survival rate between the two groups according to the Kaplan-Meier analysis were not different. Conclusion : A large number of FF does not imply a bad prognosis in patients with UIP.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.515-530
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• 2021

This study is to estimate soil moisture (SM) using Sentinel-1A/B C-band SAR (synthetic aperture radar) images and Multiple Linear Regression Model(MLRM) in the Yongdam-Dam watershed of South Korea. Both the Sentinel-1A and -1B images (6 days interval and 10 m resolution) were collected for 5 years from 2015 to 2019. The geometric, radiometric, and noise corrections were performed using the SNAP (SentiNel Application Platform) software and converted to backscattering coefficient of VV and VH polarization. The in-situ SM data measured at 6 locations using TDR were used to validate the estimated SM results. The 5 days antecedent precipitation data were also collected to overcome the estimation difficulty for the vegetated area not reaching the ground. The MLRM modeling was performed using yearly data and seasonal data set, and correlation analysis was performed according to the number of the independent variable. The estimated SM was verified with observed SM using the coefficient of determination (R²) and the root mean square error (RMSE). As a result of SM modeling using only BSC in the grass area, R² was 0.13 and RMSE was 4.83%. When 5 days of antecedent precipitation data was used, R² was 0.37 and RMSE was 4.11%. With the use of dry days and seasonal regression equation to reflect the decrease pattern and seasonal variability of SM, the correlation increased significantly with R² of 0.69 and RMSE of 2.88%.

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.153-157
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• 2007

본 논문은 지표면 현상의 관측에 날씨의 영향을 거의 받지 않는 마이크로파 L-밴드(1.95 GHz)와 C-밴드(5.3 GHz) scatterometer 시스템을 이용하여 농업과학기술원 내의 논에서 자라는 추청벼를 대상으로 2006년 5월 29일부터 10월 9일까지 생육에 따른 군락의 후방산란계수를 관측한 데이터와 작물의 생육과의 관계를 살펴보고 또한，측정 시스템의 개요，측정 시스템의 보정 방법들을 기술하고자 한다. Scatterometer 시스템의 송 수신기로 HP 8753D 벡터 네트워크 분석기를 사용하며，타워 위에 안테나를 설치하여 3.4 m의 높이에서 측정하도록 하였다. L-밴 드와 C-밴드 scatterometer는 VV-, VH-, HV-, HH-편파를 측정하여 fully polarimetric한 데이터를 얻도록 설계된 레이더시스템으로 입사각을 $30^{\circ}{\sim}60^{\circ}$에서 $10^{\circ}$간격으로 각각 30개의 독립적인 샘플을 측정하여 통계적으로 후방산란계수를 얻었다. 타워에서 발생하는 전파 잡음과 안테나 패턴의 부엽에 의한 지면에서의 수직반사(coherent 성분) 전파를 제거하기 위해 네트워크 분석기의 time gating 기능을 사용하며，55 cm 크기의 trihedral 전파반사기를 보정용 반사기로 사용하고， STCT(single target calibration technique) 방법을 이용하여 시스템을 보정하였다. 측정 결과를 분석하여 주파수， 입사각도， 편파의 변화에 대한 벼의 후방산란 특성과 벼의 생육상태과의 관계를 살펴보았다. L-밴드와 C-밴드 모두 벼의 생육과 밀접한 결과를 나타내었으나，입사각이 작을 때는 C-밴드와의 상관이 높게 나타났고 입사각이 커질수록 L-밴드와의 상관이 높게 나타났다. 편파는 L-밴드 와 C-밴드 모두 hh 편파가，입사각은 50도에서 가장 생육의 변이를 잘 설명하는 것으로 나타났다. 생육 데이터 모두를 이용한 경우보다는 유수형성기 또는 출수기 등 벼 생육의 질적인 변화를 보이는 시기에 따라 나누어 분석하는 것이 변화추이를 더 잘 설명하는 것으로 나타났다.

• Proceedings of the Korean Vacuum Society Conference
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• 1994.02a
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• pp.50-50
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• 1994

Half-metallic Heusler alloys (NiMnSb, ppdMnSb, pptMnSb) have attracted much attention due to their unique electronic and magnetic structures. Sppin-ppolarized band structure calculation ppredicts metallic behavior for the majority sppin states and semiconductor behavior for the minority sppin states. We have studied the electronic structures of these half-metallic Heusler alloys by core-level pphotoemission sppectroscoppy of Mn 2pp and 3s XppS sppectra. We found large intensities of Mn 2pp satellites and 3s exchange spplitting comppared with other metal Mn-alloys. These satellite structure can be understood by applying Anderson imppurity model. This fact supports the calculated sppin pprojected ppartial density of states which suggests that the valence electrons be highly sppin ppolarized near Fermi level and that the electrons involved with charge-transfer be mainly minority sppin ones which have semiconducting band structure. The trend of charge transfer energies Δ from ligands (Sb 5pp) to Mn 3d, obtained from our model fitting, is consistent with that calculated from sppin pprojected ppartial density of state. Also the trend of d-d electron correlation energies U calculated from Mn Auger line L3 VV by Mg $K\alpha$ source is comppatible with that resulted from our model fitting. We fitted the Mn 3s curve in the same way as for insulating Mn comppounds by using the same pparameters calculated from Mn 2pp curve fitting exceppt for the Coulomb interaction energy Q between core hole and d-electrons. The 3s sppectra were analyzed by combing the charge transfer model and a simpple model taking into account the configuration mixing effect due to the intra-shell correlation. We found that the exchange interaction between 3s hole and 3d electrons is mainly respponsible for the satellite of Mn 3s sppectra. This is consistent with the neutron scattering data, which suggests local 3d magnetic moment. We find that the XppS analysis results of Mn 2pp and 3s satellite structures of half-metallic Heusler alloys are very similar to those of insulating transition metal comppounds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.1
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• pp.46-56
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• 1979

Korean wheat varieties were tested to evaluate quality characters and the degree of deterioration due to simulated rainfall treatment. The result indicated that old varieties were generally superior in milling, flour color and dough properties to new varieties. And the quality properties of Korean new varieties were not exceeded those of Japanese varieties.

• Korean Journal of Remote Sensing
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• v.40 no.2
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• pp.229-241
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• 2024

With the advancement of big data processing technology using cloud platforms, access, processing, and analysis of large-volume data such as satellite imagery have recently been significantly improved. In this study, the Change Detection Method, a relatively simple technique for retrieving soil moisture, was applied to the backscattering coefficient values of pre-processed Sentinel-1 synthetic aperture radar (SAR) satellite imagery product based on Google Earth Engine (GEE), one of those platforms, to estimate the surface soil moisture for six observatories within the Yongdam Dam watershed in South Korea for the period of 2015 to 2023, as well as the watershed average. Subsequently, a correlation analysis was conducted between the estimated values and actual measurements, along with an examination of the applicability of GEE. The results revealed that the surface soil moisture estimated for small areas within the soil moisture observatories of the watershed exhibited low correlations ranging from 0.1 to 0.3 for both VH and VV polarizations, likely due to the inherent measurement accuracy of the SAR satellite imagery and variations in data characteristics. However, the surface soil moisture average, which was derived by extracting the average SAR backscattering coefficient values for the entire watershed area and applying moving averages to mitigate data uncertainties and variability, exhibited significantly improved results at the level of 0.5. The results obtained from estimating soil moisture using GEE demonstrate its utility despite limitations in directly conducting desired analyses due to preprocessed SAR data. However, the efficient processing of extensive satellite imagery data allows for the estimation and evaluation of soil moisture over broad ranges, such as long-term watershed averages. This highlights the effectiveness of GEE in handling vast satellite imagery datasets to assess soil moisture. Based on this, it is anticipated that GEE can be effectively utilized to assess long-term variations of soil moisture average in major dam watersheds, in conjunction with soil moisture observation data from various locations across the country in the future.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.997-1008
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• 2023

Ship detection at sea can be performed in various ways. In particular, satellites can provide wide-area surveillance, and Synthetic Aperture Radar (SAR) imagery can be utilized day and night and in all weather conditions. To propose an efficient ship detection method from SAR images, this study aimed to apply the You Only Look Once Version 5 (YOLOv5) model to Sentinel-1 images and to analyze the difference between individual vs. integrated models and the accuracy characteristics by polarization. YOLOv5s, which has fewer and lighter parameters, and YOLOv5x, which has more parameters but higher accuracy, were used for the performance tests (1) by dividing each polarization into HH, HV, VH, and VV, and (2) by using images from all polarizations. All four experiments showed very similar and high accuracy of 0.977 ≤ AP@0.5 ≤ 0.998. This result suggests that the polarization integration model using lightweight YOLO models can be the most effective in terms of real-time system deployment. 19,582 images were used in this experiment. However, if other SAR images,such as Capella and ICEYE, are included in addition to Sentinel-1 images, a more flexible and accurate model for ship detection can be built.