• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.632-634
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• 2004

First for high-qualify images and reducing process-error and driving speed, the designed 8-bit data driving circuit consists of a constant transconductance bias circuit, D-F/Fs by shift registers using static transmission gates, 1st latch and 2nd latch by tristate inverters, level shifters, current steering segmented D/A converters by 4MSB thermometer decoder and 4LSB weighted type. Second, we designed gray amp for power saving. These data driving circuits are designed with $0.35-{\mu}m$ CMOS technologies at 3.3 V and 18 V power supplies and simulated with HSPICE.

• 한국통신학회논문지
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• 제24권6B호
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• pp.1142-1148
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• 1999

본 논문에서는 Ku-밴드의 마이크로파 대역에서 위상배열 안테나에 사용 가능한 결합선로를 이용하여 위상천이기에서 기존에 고려하지 않았던 주파수에 따른 분산특성을 전파(Full-wave) 해석방법인 SDA(Spectral Domain Approach)를 사용하여 정확히 해석하였다. 또한 비대칭 결합선로를 사용하는 위상천이와 유전치 덮개층이 부가된 위상천이기의 설계를 제안하였다. 현재 사용되고 있는 대칭 결합선로를 이용한 쉬프만 위상천이기와 비교하여, 이에 대한 위상응답의 특성변화에서 통과대역의 위상편차가 줄고 대역폭이 확대되어 광대역 특성이 개선되는 것을 이론적으로 해석하고 실험을 통하여 검증하였다.

• 전기학회논문지
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• 제64권2호
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• pp.276-279
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• 2015

This paper propose a method to reduce the backscatter field of the curved aluminum plate using the cancellation system. The cancellation circuit is composed of a circulator, a LNA(Low Noise Amplifier), a VGA(Variable Gain Amplifier) and two phase shifters. Prior to experiment, we performed simulations to confirm the possibility using FDTD(Finite Difference Time Domain) simulator. We confirmed that the backscatter field could be reduced by the cancellation circuit when we changed the appropriate gain and phase. Finally, we performed an experiment to verify the performance of the cancellation circuit.

• 전자공학회논문지A
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• 제31A권5호
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• pp.68-75
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• 1994

A new Predistortor that is designed using Feedforward type is proposed to overcome the nonlinearity of HPA (High Power Amplifier). HPA has the nonlinearity of the gain compression and phase distorton, so digital communication system of multi-carrier TDMA needs the linear RF transmitter. Using IMD (Intermodulation Distortion) of drive amplifier, as Feedforward type, the inverse IMD is coupled to the main loop with variable attenuators, phase shifters, and sub-amplifiers well designed. At the input of main amplifier, the over-coupled IMD surpresses the main amplifier 's IMD. Adjusting the level and phase of IMD at the sub loop, C/I of HPA is better than before correction.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권3호
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• pp.169-174
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• 2006

In this work, we demonstrate a novel compact mechanical beam steering transmitter based on a direct vertical integration of a 2-D MEMS-based mechanical beam steering antenna with a VCO on a single silicon platform. By eliminating the long feed lines and waveguide metal blocks, the radiation pattern has been improved vastly, resulting in an almost ideal pattern at every scan angle. The losses incurred by the feed lines and phase shifters are also eliminated, which allows the transmitter to be implemented using only a single VCO. The system complexity has been greatly reduced with a total module size of only 1.5 cm ${\times}$ 1.5 cm ${\times}$ 0.4 cm. This work demonstrates that RF MEMS can be a key enabling technology for high-level integration.

• ETRI Journal
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• 제39권3호
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• pp.319-325
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• 2017

The decoding process of a quasi-cyclic low-density parity check code requires a unique type of rotator. These rotators, called multi-size cyclic-shifters (MSCSs), rotate input data with various sizes, where the size is the amount of data to be rotated. This paper proposes a low-complexity MSCS structure for the case when the sizes have a nontrivial common divisor. By combining the strong points of two previous structures, the proposed structure achieves the smallest area. The experimental results show that the area reduction was more than 14.7% when the proposed structure was applied to IEEE 802.16e as an example.

• 한국언어정보학회지:언어와정보
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• 제14권2호
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• pp.33-46
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• 2010

This paper introduces a new linguistic-focused approach for sentiment analysis (SA) of Korean. In order to overcome shortcomings of previous works that focused mainly on statistical methods, we made effective use of various linguistic features reflecting the nature of Korean. These features include contextual shifters, modal affixes, and the morphological dependency of chunk structures. Moreover, in order to eschew possible confusion caused by ambiguous words and to improve the results of SA, we also proposed simple adjustment methods of word senses using KOLON ontology mapping information. Through experiments we contend that effective use of linguistic features and ontological information can improve the results of sentiment analysis of Korean.

• 한국통신학회논문지
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• 제12권4호
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• pp.325-334
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• 1987

PIN 다이오드를 利用한 反射形 移相器는 4端子網 임피던스 變換回路로 構成될 수 있는데 원하는 移相量을 얻기위한 設計方程式 誘導에 假想 임피던스法을 적용하였다. 실제로 2-bit($22.5^{\circ}$와 $45^{\circ}$)하이브리드 移相器를 設計 具現하여 中心周波數(10GHz)에서 $22.5^{\circ}$bit는 $0.5^{\circ}$, $45^{\circ}$bit는 $0^{\circ}$의 移相量 誤差의 것을 얻었으며 main beam 制御用 phased-array안테나를 위한 移相器設計에 이 方法을 사용할 수 있음을 立證하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.422-425
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• 1988

The structure consisting of an E-plane dielectric slab partially filling a rectangular waveguide is examined with attention on those higher order mode propagation characteristics that are relevant to the design of nonreciprocal remanence ferrite phase shifters. The mechanisms for the elimination of $LSE_{11}$, $LSM_{11}$, $LSE_{12}$ modes are introduced. Experimental verification of elimination of higher order mode is shown in the form of insertion loss measurements.

• 한국광학회지
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• 제4권4호
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• pp.397-402
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• 1993

위상변이간섭법(phase-shifting interferometry)의 측정정도는 광원의 불안정성, CCD센서의 비선형성, 열팽창, 기계적 진동과 위상변이기(phase shifter)의 위치결정정도 등에 의해 영향을 받는다. 위상변이 간섭법에서 형상을 측정하기 이해 사용되는 이론적인 기준위상(theoretical reference phase)은 위상변이기의 이동오차와 광경로차에 변화를 주는 열팽창, 기계적 진동 등에 의해서 실제의 기준위상(actual reference phase)과 다르게 되고 이것은 측정에 심각한 오차를 야기시킨다. 이러한 종류의 위상측정오차를 제거하기 이해 본 연구에서는 최소자승법과 반복연산법을 사용하여 간섭무늬의 광강도로부터 직접 기준위상을 구하고, 이를 이용하여 위상을 산출하는 방법이 제안되었다.