• 한국통신학회논문지
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• 제27권3A호
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• pp.196-204
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• 2002

STC(Sinusoidal Transform Coding) 방식은 주파수 영역에서 음성신호의 스펙트럼 피크치들을 정현파로 모델링하여 합성하는 음성부호화 방식을 말한다. 저전송률 STC 방식에서는 스펙트럼의 모든 피크를 이용하는 대신, 기본 주파수와 고조파에 해당하는 스펙트럼 포락선에서의 크기와 그때의 위상을 이용하여 음성을 합성한다. 본 논문에서는 정현파 모델에 기반한 2.4kbps 음성부호화 알고리즘을 제안한다. 피치정보는 모든 스펙트럼 피크를 사용한 합성음과 선택된 주파수와 고조파를 이용한 합성음과의 평균자승에러를 이용하여 추정하고, 위상정보는 여기신호 펄스의 시작시기를 나타내는 onset time과 성도 모델 전달함수의 위상을 이용하여 얻는다. 크기정보는 SEEVOC 알고리즘과 선형예측계수를 이용하여 추정한다. 실험결과, 합성음의 스펙트럼 특성은 원음성의 포만트 정보를 대부분 가지고 있으며, 위상정보도 원음성의 위상을 잘 따라감을 확인하였다. 합성음의 음질평가를 위해서 informal한 MOS(Mean Opinion Score) 테스트를 시행하였으며, 2.0kbps의 HVXC와 비교하여 대체적으로 MOS 3.1 이상의 음질을 얻을 수 있었다.

• 한국군사과학기술학회지
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• 제16권2호
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• pp.191-198
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• 2013

Geo-pointing is a function that maintains LOS(Line of Sight) to a stationary ground target by controlling azimuth and elevation angles of a EOS(Electro-Optical System) which are calculated from aircraft navigation data and target coordinates. In design and implementation of the geo-pointing, a transmission time delay between GPS/INS and EOS is a major degradation factor of the geo-pointing performance when the aircraft is rapidly maneuvered especially. In this paper, a kalman filter is designed to compensate the transmission time delay of aircraft navigation data. Simulation and test results show that the geo-pointing performance is enhanced by the proposed compensation technique.

• 디지털산업정보학회논문지
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• 제4권2호
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• pp.49-55
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• 2008

Combining OFDMA with MIMO is the key technology for the 4G mobile communication. OFDMA can relieve inherent difficulties of high-speed transmission. MIMO technology can be largely categorized into two techniques: one is STC for diversity gain and the other is SM for high frequency efficiency. In this paper, we depict various MIMO techniques of two transmit antenna and compare the computational complexity of decoding process for the techniques. Then, we analysis the performance of the techniques in the WiBro downlink environment based on OFDMA. We perfer ML algorithm which is the optimum performance and ZF algorithm of least computational complexity for SM detection.

• Journal of Communications and Networks
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• 제9권2호
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• pp.177-184
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• 2007

Alamouti space-time code (STC) is a part of the UMTS-WCDMA standard. However, up to the best of our knowledge no exact closed-form outage and bit error probability (BEP) formulas for this famous code exists. Evaluating its performance through simulations is time-consuming and therefore, there should be analytical performance graphs to serve as a reference which are derived in this paper for coherently MPSK-modulated data. Additionally, analytical results take into account different channel fading levels from transmit antennas to receive ones.

• International Journal of Industrial Entomology and Biomaterials
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• 제9권2호
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• pp.269-272
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• 2004

Different methods of cold storing of bivoltine eggs are in practice to postpone hatching. Bivoltine eggs undergo hibernation if they are not acid treated within 20 - 24 hrs of oviposition, which depends on race, ambient temperature and humidity. The schedules adopted for cold storing include hibernation schedule (Hib), ordinary chilling (OC), short term chilling (STC) and acid treated layings (AT). Peanut cocooning race ${NB_4}{D_2}$ has been subjected for the present assessment. Cocoons harvested from the crop pertaining to all the four methods of cold storing have been used for producing different combinations and acid treated followed by rearing. The performance in respect of chawki loss, maximum larval weight 4({5^th} age)$, yield/ 10,000 larvae (no), cocoon and shell weight showed maximum values for hibernation ${\times}$ hibernation combination followed hibernation with OC and hibernation with AT. Lowest performance was recorded when STC batch source females were used.

• 열처리공학회지
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• 제10권1호
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• pp.71-78
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• 1997

This work was to investigate suitable tool steels for hardening using laser beam, and was studied on carbon tool steels and alloyed tool steels such as STC3 steel, STS3 steel, STD11 steel and SKH51 steel. The surface hardness of HV700-1000 and the hardening depth of 2-2.5mm were obtained on STC3 steel and STS3 steel, and HV800-1000 was obtained on SKH51 steel, but STD11 steel was not enough. Except STD11 steel, all steels used in this study can be hardened by laser quenching or laser rapid melting.

• Journal of Astronomy and Space Sciences
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• 제38권3호
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• pp.157-164
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• 2021

We describe a method for the in-orbit calibration of body-mounted magnetometers based on the CHAOS-7 geomagnetic field model. The code is designed to find the true calibration parameters autonomously by using only the onboard magnetometer data and the corresponding CHAOS outputs. As the model output and satellite data have different coordinate systems, they are first transformed to a Star Tracker Coordinate (STC). Then, non-linear optimization processes are run to minimize the differences between the CHAOS-7 model and satellite data in the STC. The process finally searches out a suite of calibration parameters that can maximize the model-data agreement. These parameters include the instrument gain, offset, axis orthogonality, and Euler rotation matrices between the magnetometer frame and the STC. To validate the performance of the Python code, we first produce pseudo satellite data by convoluting CHAOS-7 model outputs with a prescribed set of the 'true' calibration parameters. Then, we let the code autonomously undistort the pseudo satellite data through optimization processes, which ultimately track down the initially prescribed calibration parameters. The reconstructed parameters are in good agreement with the prescribed (true) ones, which demonstrates that the code can be used for actual instrument data calibration. This study is performed using Python 3.8.5, NumPy 1.19.2, SciPy 1.6, AstroPy 4.2, SpacePy 0.2.1, and ChaosmagPy 0.5 including the CHAOS-7.6 geomagnetic field model. This code will be utilized for processing NextSat-1 and Small scale magNetospheric and Ionospheric Plasma Experiment (SNIPE) data in the future.

• 대한수의학회지
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• 제41권3호
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• pp.333-342
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• 2001

To detect the genetic variations among infectious bursal disease (IBD) vaccine strains, the hypervariable region of VP2 gene of seven IBDV vaccine strains were amplified using reverse transcriptase/polymerase chain reation(RT/PCR). Ampllified PCR products of IBDV were cloned, sequenced, and compared with published sequences for IBDV. Vaccine strains (JOONG, HAN, B7, IB, BU2, G2, CIL) used in Korea and Korean field isolates (SH/92, K1, 310) had 81%(310 and HAN) ~ 98%(SH/92 and CIL) amino acid sequence similarity. Vaccine strains had 80%(HAN and IB) ~ 99%(JOONG and BU2) amino acid sequence similartiy. Intermediate plus vaccine strain, CIL was not substituted at positions 279(D $\rightarrow$ N) and 284(A $\rightarrow$ T), and conserved in serine-rich heptapeptide. At the two hydrophilic region, JOONG, IB and Bu2 strains had identical amino acid sequence comparing with STC strain. By phylogenetic analysis, JOONG and DAE strains were categorized in same group with BU2. The CIL and STC strains closely related but seperated from G2, HAN, B7 and IB strains.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
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• pp.131-131
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• 1998

In the course of screening for new natural compounds having antioxidant activity from microbials, mushrooms as well as plants. We have isolated novel sesquiterpenoid and officinalic acid from methanolic extracts of Stereum ostrea. The dried fruit body( 450 g) of Stereum ostrea was extracted with methanol, then methanolic extract was partitioned between water and hexane, chloroform, and ethyl acetate, subsequently. The chloroform extract was subjected on silica gel, Sephadex LH-20 and RP-18 column chromatography, successively. And two compounds were isolated and identified as new triterpenoids and officinalic acid using $^1$H - NMR, $\^$13/C - NMR as well as Mass spectra.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.516-517
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• 2013

신재생 에너지의 비중 확대와 보급이 늘어남에 따라, 국가 간, 도시 간의 송전이 중요한 이슈로 대두 되고 있다. 위와 같은 요구 조건을 만족시키기 위해서 초고압 직류 송전의 개발이 필요하다. 초고압 직류송전(HVDC)에는 전류형과 전압형으로 나뉘는데. 각 HVDC에서 사용되는 Valve는 실제 운전 전에 여러 가지 방법으로 검증이 필요하다. 합성 시험회로 설비(Synthetic Test Circuit = 이하 STC)는 전류형 HVDC에서 사용되는 주요 전력변환 장치로, Thyristor Valve의 동작을 실제 동작 조건에 맞추어 동작을 시켜, 동작의 신뢰성을 검증하는 시험 설비이다. 본 논문에서는 전류형 HVDC Valve의 Operational Test를 위한 STC의 보호기능에 대해 기술하고 있다. 합성시험회로는 2상 초퍼와 6 펄스 사이리스터 컨버터를 사용하였고 설계된 보호기능은 PSCAD를 사용하여 검증하였다. HVDC Valve Operational Test시 합성시험회로 내에서 발생할 수 있는 사고 상황을 상정하고 그에 따른 보호 기능을 모의하였다.