• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.4
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• pp.327-334
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• 2010

Recently developed aircrafts use Fly-By-Wire(FBW) or Fly-By-Light(FBL) system. These systems have some merits; they can perform very complicated missions, they can expand the flight region and improve the reliability of the aircrafts. With the development of flight control systems that use FBW technique, flight envelope protection concept is introduced to guarantee reliability of the aircraft and improve the efficiency of mission achievement. In this study, flight envelope protection system is designed using a dynamic trim algorithm, a peak response estimation, and a gain scheduling technique. The performance of these methods are compared by performing numerical simulation.

• Korean Journal of Animal Reproduction
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• v.19 no.4
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• pp.293-305
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• 1996

Retrovirus는 DNA가 아닌 RNA를 유전 물질로 갖고 있는 동물 virus인데 각 virus는 RNA와 함께 크게 gag, pol. 그리고 env 등의 3가지 단백질로 구성되어 있다. gag 단백질은 virus의 내부구조를 형성하는 단백질이고, pol단백질은 감염을 통해 표적 세포에 도입된 retrovirus의 RNA를 DNA로 역전사시키는 reverse transcriptase의 역할을 하며, env단백질은 virusdml 외부를 구성하는 단백질로써 이 단백질에 의해 각 retrovirus의 종류에 따른 감염이 가능한 표적세포의 종류가 결정된다(host cell specificity). 따라서 어떤 retrovirus의 envelope단백질과 표식세포에 있는 retrovirus의 envelope 단백질에 대한 특정 receptor와의 상호 작용에 의해 세포속으로 도입된 virus의 RNA는 reverse transcriptase에 의해 DNA로 역전사된 후 표적세포의 genomic DNA에 삽입되는 특징을 가진다. 이러한 특징을 가진 retrovirus vector system은 형질 전환 동물의 생산에 있어서 현재까지의 주된 방법인 수정란의 pronucleus에의 DNA microinjection방법 보다 여러 가지 면에서 우수함에도 불구하고 쥐 이외의 다른 동물에서는 거의 이용되고 있지 않는 실정이다. 주된 원인으로는 현재 사용되고 있는 대부분의 retrovirus vector system이 쥐의 백혈병 virus를 근간으로 하기 때문에 이 system에서 생산된 virus는 쥐 이외의 다른 동물, 특히 유제류의 세포에는감염성이 아주 약하기 때문이다. 이러한 결점을 해결하기 위하여 최근에 기존의 쥐 백혈병 virus의 envelope protein을 vesicular stomatitis virus의 G protein으로 대체한 hybrid retrovirus vector system이 개발되었다. 이러한 system에서 생산되는 virus는 조류를 포함한 거의 모든 종류의 동물세포를 감염시킬 수 있으며 몇몇 특정세포에 대해서는 기존의 retrovirus vector system에 비해 1,000배 이상의 높은 감염도를 나타내는데 그 특징이 있다. 따라서 이러한 새로운 virus vector system을 이용할 경우, 보다 다양한 종에 있어서 형질전환 동물을 효율적으로 생산할 수 있을 뿐만 아니라 형질전환 동물의 생산 방법 자체를 다양화 시킬 수 있다고 본다.

• Proceedings of the KOSOMBE Conference
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• v.1991 no.11
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• pp.34-36
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• 1991

본 논문에서는 저주파의 envelope와 고주파의 neural oscillation 신호의 곱으로 이루어진 EEG 신호의 envelope를 추출을 하기 위하여 multiplicative homomorphic 시스템을 사용하였다. 이 방법은 다른 방법에 비하여 처리 과정이 간단하여 계산량이 감소되어 실시간 envelope 추출의 가능성을 보였으며, 또 neural oscillation signal의 주파수가 변하여도 정확한 envelope 추출할 수 있는 우수한 적응력을 보였다.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.72.3-72.3
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• 2016

A massive envelope and a strong bipolar outflow are the two most distinct structures of youngest protostellar systems. We present observational results from the Combined Array for Research in Millimeter-wave Astronomy (CARMA) toward the youngest (Class 0) protostellar system L1157. At an angular resolution of 5 arcseconds, we mapped its well-developed outflow in CO 2-1 over a span of approximately 5 arcminutes. Additionally, we imaged the central envelope with CO isotopes, CS, CN, and N2H+ with an angular resolution of about 2 arcseconds. We show that the bipolar outflow may be represented with a two jet model and constrain its physical properties such as precession/rotation directions, velocities, inclinations, and position angles via cube data fitting. In addition, we discuss the kinematic features of the envelope detected in CO isotopes and N2H+ and present the radius-dependent dust opacity spectral index.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.6
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• pp.153-164
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• 2019

The presence of thermal bridges in a building envelope cause additional heat loss which increases the heating energy. Given that a higher building insulation performance is required in these cases, the heat loss via thermal bridges is a high proportion of the total heat energy consumption of a building. For the dry exterior insulation system that uses mullions and transoms to fix insulation and exterior materials such as stone and metal sheet, the occurrence of thermal bridges at mullions and transoms is one of the main reasons for heat loss. In this study, a dry exterior insulation system using the truss insulation frame (TIF) was proposed as an alternative to metal mullions. To evaluate the building envelope performance, structural, air-leakage, water-leakage, fire-resistance, thermal, and condensation risk tests were conducted. In addition, the annual energy consumption associated with heating and cooling was calculated, including the linear thermal transmittance of the thermal bridges. As a result, the dry exterior insulation system using TIF achieved the allowable value for all tests. It was also determined that the annual heating load of a building was reduced by 36.7 % when the TIF dry exterior insulation system was used, relative to the dry exterior insulation system using steel pipes without additional insulations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1719-1726
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• 2002

Design variables and design parameters are rarely deterministic in practice. Robust optimal design takes into consideration of the uncertainties in the design variables and parameters. Robust optimization methodology with probability constraints requires a lot of system analyses fer calculating failure probability of each constraint. By introducing an envelope function to reduce the number of constraints, efficiency of robust optimization techniques can be considerably improved. Through four illustrative examples, it is shown that the number of system analyses is greatly decreased while little differences in the optimum results are observed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.160-164
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• 2004

In DS/CDMA(direct sequence code division multiple access) system using the approximated analytic chip waveforms are applied. Proposed chip waveforms are classified into 2 types: uniform chip waveforms with uniform envelope and non-uniform chip waveforms with non-uniform envelope. It has confirmed that the similarity of the approximated analytical chip waveforms is compared using chip waveforms, envelope, phase, correlation, and bandwidth properties.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.4
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• pp.335-340
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• 2021

A constant envelope multiplexing via constellation tailoring scheme is proposed for flexible power allocation of Global Navigation Satellite System (GNSS) signals. The proposed scheme is compared with the coherent adaptive subcarrier modulation (CASM) adopted in the L1 band signals of the Global Positioning System (GPS) in terms of power difference and power loss. Analysis of the constellation optimization results on the power difference and power loss show that the proposed scheme outperforms the CASM of the GPS signals in the allowable power difference of less than 0.1 dB.

• ETRI Journal
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• v.30 no.3
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• pp.377-382
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• 2008

A novel power amplifier for a polar transmitter is proposed to achieve better spectral performance for a wideband envelope signal. In the proposed scheme, 2-bit sigma-delta (${\Sigma}{\Delta}$) modulation of the envelope signal is introduced, and the power amplifier configuration is modified in a binary form to accommodate the 2-bit digitized envelope signals. The 2-bit ${\Sigma}{\Delta}$ modulator lowers the noise of the envelope signal by fine quantization and thus enhances the spectral property of the RF signal. The Ptolemy simulation results of the proposed structure show that the spectral noise is reduced by 10 dB in a full transmit band of the EDGE system. The dynamic range is also enhanced. Since the performance is improved without increasing the over-sampling ratio, this technique is best suited for wireless communication with high data rates.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.79-82
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• 2017

In this paper, we proposed the wireless communication system using millimeter-wave envelope detector. The sub-harmonic mixer based on schottky barrier diode was used in the transmitter. The receiver was used millimeter-wave envelope detector. The transmitter was composed of schottky diode sub-harmonic mixer, frequency tripler, and horn antenna. The receiver was composed of horn antenna, millimeter-wave envelope detector, low pass filter, base band amplifier, and limiting amplifier. At 1.485 Gbps and 300 GHz, the eye-diagram showed a very good performance as measured by the error free. Communication distance is reduced compared to the heterodyne receiver, but compact and lightweight is possible.