• 전기학회논문지
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• 제56권9호
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• pp.1648-1654
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• 2007

In this paper, we consider the design of $H_\infty$ high-gain state feedback control for time-delayed linear systems with limited actuator capacities. The high-gain control means that the control permits the predetermined degree of saturation. Based on new Lyapunov-Krasovskii functional, we derive a result in the form of matrix inequalities. The matrix inequalities are consisted of LMIs those confirm the positive definiteness of Lyapunov- Krasovskii functional, satisfaction of predetermined degree of saturation, reachable set and $L_2$ gain constraint. The result is dependent on the bound of time-delay and its rate, predetermined degree of saturation, actuator capacity, and the allowed size of disturbances. Finally, we give a numerical example to show the effectiveness and usefulness of our result.

• 전기학회논문지
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• 제56권1호
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• pp.161-166
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• 2007

In this paper, two 4$\times$4 rectangular patch array antennas operating at 20 GHz are implemented for the satellite communication. The sixteen patch antennas and microstrip feeding line are printed on a single-layered substrate. The design goal is to achieve high directivity and gain by optimizing design parameters through permutations in element spacing. The spacing between the array elements is chosen to be 0.736$\lambda$. Numerical simulation results indicate that the HPBW(Half-Power Beam Width) of the 4$\times$4 patch array antenna is 18.78 degrees in the E-plane and 18.48 degrees in the H-plane with a gain of 17.18 dBi. Numerical simulations of a 4$\times$4 recessed patch array antenna yield a HPBW of 18.71 degrees in the E-plane and 17.82 degrees in the H-plane with a gain of 19.43 dBi.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.49-52
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• 1988

This paper deal with the robust high gain controller design technique by inner-loop feedback, output feedback, feedforward compensation, and presented the algorithm to be required the determination of gain matrix. Using this control scheme, simulation results have bean tested for the linearized model of the aircraft.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.69-71
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• 2005

DC servo motors have a defect that they need a periodical maintenance because of a brush commutation and also they have a difficulty at high speed operation. In this reason, the use of AC Servo motors are increasing these days. In this paper, a proposed neuro observer is applied to speed control of AC servo motor. The proposed observer complement a problem that occur from increase of gain of High-gain observer in proportion to the square number of observable state variables. And also, the proposed observer can tune the gain obtained by differentiating observational error automatically by using the backpropagation training method to stabilize the observational speed. The excellence and feasibility of the proposed observer is proved by making a comparison test between the proposed observer and the others applied to the same AC servo motor.

• 전기전자학회논문지
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• 제2권2호
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• pp.263-269
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• 1998

릴레이 대신 포화함수를 이용하여 선형 플랜트의 극한 이득과 주기를 결정하였다. 포화함수를 사용함으로서 플랜트의 고주파 성분을 감소 시켜 묘사함수 사용에 의한 극한이득과 주기 결정의 정확도를 증가시켰다. 또한 적절한 포화함수를 사용할 수 있는 간단한 절차를 기술하였으며 진동이 발생하지 않는 플랜트에 대해서 지연요소를 이용한 자동동조 방법을 제시하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
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• pp.5-8
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• 2000

This paper shows the high performance as a photodetector of InGaP/GaAs HPT with 3-terminal caused by its inherent good electrical properties compared with AIGaAs/GaAs HPT. InGaP/GaAs HPT produced the high optical gain of about 61 where HPT is biased at Vc=3V, Iв=2${\mu}\textrm{A}$ with an input optical power of 1.23㎼. This is 2.5 times higher than that of AIGaAs/GaAs HPT. And we examined that the optical gain of HPTs becomes larger when operating in 3-terminal configuration rather than 2-terminal with the floating base. for a given base current of 2${\mu}\textrm{A}$, the optical gain is enhanced about 18% in the InGaP/GaAs HPT and about 27% in the AIGaAs/GaAs HPT over that of the 2-terminal device.

• 제어로봇시스템학회논문지
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• 제3권1호
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• pp.1-8
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• 1997

In order to reject the steady-state tracking error, it is common to introduce integral compensators in servosystems for constant reference signals. However, if the mathematical model of the plant is exact and no disturbance input exists, the integral compensation is not necessary. From this point of view, a two-degree-of-freedom(2DOF) servosystem has been proposed, in which the integral compensation is effective only when there is a modeling error or a disturbance input. The present paper considers robust stability of this 2DOF servosystem incorporating an observer to the structured and unstructured uncertainties of the controlled plant. A robust stability condition is obtained using Riccati inequality, which is written in a linear matrix inequality (LMI) and independent of the gain of the integral compensator. This result impies that if the plant uncertainty is in the allowable set defined by the LMI condition, a high-gain integral compensation can be carried preserving robust stability to accelerate the tracking response.

• Transactions on Electrical and Electronic Materials
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• 제18권5호
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• pp.250-252
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• 2017

High-performance full swing logic inverters were fabricated using amorphous 1 wt% Si doped indium-zinc-oxide (a-SIZO) thin films with different channel layer thicknesses. In the inverter configuration, the threshold voltage was adjusted by varying the thickness of the channel layer. The depletion mode (D-mode) device used a TFT with a channel layer thickness of 60 nm as it exhibited the most negative threshold voltage (-1.67 V). Inverters using enhancement mode (E-mode) devices were fabricated using TFTs with channel layer thicknesses of 20 or 40 nm with excellent subthreshold slope (S.S). Both the inverters exhibited high voltage gain values of 30.74 and 28.56, respectively at $V_{DD}=15V$. It was confirmed that the voltage gain can be improved by increasing the S.S value.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.326-329
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• 2009

This paper proposes a new video compression algorithm using an adaptive transform that is adjusted depending on the frequency contents of the input signals. The adaptive transform is based on the warped discrete cosine transform (WDCT) which is shown to provide better performance than the DCT at high bit rates, when applied to JPEG compression scheme [1, 2, 3]. The WDCT is applied to the video compression in this paper, as a new feature in the H.264/AVC. The proposed method shows the coding gain over the H.264/AVC at high bit rates. The coding gain is shown over the 35dB PSNR quality, and the gain increases as the bit rate increases. (about 1.0dB at 45dB PSNR quality at maximum)

• 한국통신학회논문지
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• 제13권5호
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• pp.444-452
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• 1988

高利得과 廣帶域 特性을 동시에 실현하기 위하여 원형 루프 안테나를 傳送線路에 의하여 交叉給電시킨 素子와 無給電 素子로 구성한 LP형태의 안테나를 제시했다. 제시한 안테나를 모멘트法에 의하여 數値解析하여 電流分布, 入力임피던스, 電力利得 및 指向性 패턴 등을 對數週期 다이폴 안테나(LPDA)와 比較 檢討하였다. 그 결과 本 論文에서 제시된 안테나는 廣帶域 特性 밑 高利得을 갖고 周波數에 따른 E, H面패턴의 변화가 거의 없었으며 LPDA보다 우수한 性能을 갖는 것으로 확인 되었다.