• 대한전자공학회논문지TC
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• 제38권11호
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• pp.49-54
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• 2001

GaAs pHEMT와 도파관-마이크로스트립 변환구조를 이용하여 고출력, 고이득 특성을 갖는 Ka-band 하이브리드 전력증폭기 모듈을 개발하였다. 본 전력증폭기는 10 mil 두께의 duroid 기판을 이용한 마이크로스트립 라인과 도파관 마이크로스트립 변환구조로 이루어져 있다. 제작된 도파관-마이크로스트립 변환구조는 32 40 GHz 대역까지 약 1 dB의 삽입손실(back to back)을 보인다. 전력증폭기 모듈의 측정 결과, 36.1 - 37.1 GHz에서 1W 이상의 출력 전력, 23dB 이상의 전력 이득을 보이며 36.5GHz에서 31dBm의 출력전력, 24dB의 전력 이득, 15%의 PAE을 나타내었다.

• 한국컴퓨터정보학회논문지
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• 제26권8호
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• pp.173-180
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• 2021

이 연구의 목적은 고등학교 진학 청소년이 지각하는 부모의 양육방식이 삶의 만족도에 미치는 영향을 파악하고 이 두 변수 사이에서 자아존중감이 매개변수로 기능하는지 확인하는 것이다. 이를 위해 지각된 양육방식, 자아존중감, 삶의 만족도 사이의 매개효과 관계를 가정하는 연구모형을 설계하였다. 연구모형을 검증하기 위해 분석한 자료는 한국아동·청소년패널조사(2010-2016)의 초4패널의 6차와 7차 자료이다. 주요 분석결과는 다음과 같다. 첫째, 부모의 민주적 양육방식은 삶의 만족도를 높이는 긍정적 효과를 나타냈으나, 통제적 양육방식이 삶의 만족도에 미치는 영향은 유의하지 않았다. 둘째, 자아존중감은 민주적 양육방식과 삶의 만족도 사이의 관계를 부분매개하였다. 셋째, 자아존중감은 통제적 양육방식과 삶의 만족도 사이의 관계를 완전매개하였다. 이와 같은 분석 결과를 바탕으로 부모의 양육방식 개선과 청소년 자녀의 자아존중감 강화를 위한 함의에 대하여 논의하였다.

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 제15회 정기총회 및 동계학술발표회
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• pp.52-53
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• 2004

• 비파괴검사학회지
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• 제30권3호
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• pp.225-235
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• 2010

There are many types of the geometric transitions such as dent, bulge, protrusion, expansion, etc, on the inner and outer surfaces of heat exchanger tubes, steam generator tubes, and condenser tubes of nuclear power plants. Such geometric transition causes a local residual stress in heat exchanger tubes and acts as a structural factor accelerating the evolution of defects, in particular stress corrosion cracks. In the conventional eddy current test methods, the bobbin coil profilometry can provide 2-dimensional geometric information on the variation of the average inner diameter along the tube length, but the 3-dimensional distribution and the quantitative size of a local geometric transition existing in the tube cannot be measured. In this paper, a new eddy current probe, developed for the 3-dimensional profile measurement, is introduced and its superior performance is compared with that from the conventional bobbin coil profilometry for the various types of geometric transition. Also, the accuracy of the probe for the quantitative profile measurement is verified by comparing the results with that from the laser profilometry. It is expected that the new eddy current probe and techniques can be effectively used for an optimization of the tube expansion process, and the management of tubes with geometric transitions in service.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1573-1576
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• 2008

A simulation system is developed to calculate the apparent motion-induced image from a sequence of temporal luminance transitions, while using the properties of the human visual system. Based on the simulation method, both edge (moving block) and detail degradation (line spreading, grating, sinusoidal pattern), and also color aberration are discussed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.583-584
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• 2008

This paper presents a low-power and high-speed pulsed flip-flop based on dual-precharging and conditional discharging. The dual-precharging operation minimizes the parasitic capacitance of each precharge node, resulting in high-speed operation. The conditional-discharging operation minimizes the redundant transitions of precharge nodes, resulting in low-power operation. Linear feedback shift register (LFSR) designed in a $0.18{\mu}m$ CMOS technology using the proposed flip-flop achieves 32% power reduction as compared to conventional design.

• Nuclear Engineering and Technology
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• 제47권6호
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• pp.669-677
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• 2015

A mechanistic model for void fraction prediction with improved interfacial friction factor in nearly horizontal tubes has been proposed in connection with the development of a condensation model package for the passive auxiliary feedwater system of the Korean Advanced Power Reactor Plus. The model is based on two-phase momentum balance equations to cover various types of fluids, flow conditions, and inclination angles of the flow channel in a separated flow. The void fraction is calculated without any discontinuity at flow regime transitions by considering continuous changes of the interfacial geometric characteristics and interfacial friction factors across three typical separated flows, namely stratified-smooth, stratified-wavy, and annular flows. An evaluation of the proposed model against available experimental data covering various types of fluids and flow regimes showed a satisfactory agreement.

• Journal of Power Electronics
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• 제17권6호
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• pp.1611-1624
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• 2017

With the rapid development of microgrid technology, microgrid projects are no longer limited to laboratory demonstrations and pilot platforms. It shows greater value in practical applications. Hence, the smooth interaction between a microgrid and the main grid plays a critical role. In this paper, a control method based on active disturbance rejection control (ADRC) is proposed in order to realize seamless transitions between grid-connected and islanding operation modes and stable operation with variable loads. It is verified by simulations that the proposed ADRC-based method features better performance when compared to conventional proportional-integral-differential (PID) control. Meanwhile, the stability of the third-order extended state observer (ESO) in second-order ADRC is validated by using Lyapunov stability criteria.

• BMB Reports
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• 제43권4호
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• pp.291-296
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• 2010

Cyclin-dependent kinase 2 (CDK2) is a member of serine/threonine protein kinases, which initiates the principal transitions of the eukaryotic cell cycle and is a promising target for cancer therapy. The present study was designed to inhibit cdk2 gene expression to induce cell cycle arrest and cell proliferation suppression. Here, we constructed a series of RNA interference (RNAi) plasmids which can successfully express small interference RNA (siRNA) in the transfected human cells. The results showed that the RNAi plasmids containing the coding sequences for siRNAs down-regulated the cdk2 gene expression in human cancer cells at the mRNA and the protein levels. Furthermore, we found that the cell cycle was arrested at G0G1 phases and the cell proliferation was inhibited by different siRNAs. These results demonstrate that suppression of CDK2 activity by RNAi may be an effective strategy for gene therapy in human cancers.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.694-697
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• 2002

Sampling rate conversion widely used in subband coding, A/D and D/A transitions etc. is an important techniques. Nyquist filters and the filter banks have been used far the sampling converter. However, they need many memories and, whenever the sampling rate is changed it is necessary to redesign filters. Then we propose design method of the new interpolation kernel. Design method of the new interpolation kernel is approximated each piecewise of lowpass filter by n th polynomials. The proposed kernel is not redesigned, whenever the sampling rate is changed. The proposed kernel is a continuous function, the sampling rate of the rational number can be converted.