• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.1
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• pp.1-6
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• 2014

In this paper, controller propose to prevent compressor surge and improve the transient response of the fuel flow control system of turbojet engine. Turbojet engine controller is designed by applying Artificial Neural Network PID control algorithm and make an inference by applying Levenberg-Marquartdt Error Back Propagation Algorithm. Artificial Neural Network inference results are used as the fuel flow control inputs to prevent compressor surge and flame-out for turbojet engine for UAV. High Gain Observer is used to estimate to compressor rotation speed of turbojet engine. Using MATLAB to perform computer simulations verified the performance of the proposed controller. Response characteristics pursuant to the gain were analyzed by simulation.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.1
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• pp.11-18
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• 2003

We consider a single-input-single-output nonlinear system which is represented in a normal form. The model contains the uncertainty. A high-gain observer is used to estimate the states variables to reject a modeling uncertainty We design the globally bounded output feedback controller using sliding mode control to stabilize the closed-loop system. The globally bounded output feedback controller reduce the peaking in the states variables. The proposed method give a more design freedom in the design of the globally bounded controller than that of the previous work.

• Journal of the Korean Institute of Telematics and Electronics
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• v.3 no.1
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• pp.3-11
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• 1966

An optimum pattern control procedure for the TV, FM broadcasting antennas being constructed in Seoul & Pusan is described. For the pattern control, 4 antenna elements were romoved from Seoul toward Inchen. Resulting pattern was measured and compared to the results of theoretical value. Similar results were obtained for Pusan antenna.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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• pp.569-575
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• 1997

모델 불확실성이 있고 n축 자유도(degree of freedom)를 갖고 있는 로봇 동작부(manipulator)에 대해서 위치 정보만을 이용하여 가변 구조 제어기(variable structure controller)를 설계하였다. 모델의 불확실성이 존재하는 경우에도 제어기에 사용되는 속도를 잘예측하기 위해 고이득 관찰기를 사용 하였으며 고이득 관찰기를 사용할때 발생할 수 있는 상태변수의 피킹현상(peak phenomenon)를 적게 하게 하기위하여 제어기의 값을 제한 (globally bounded)하여 제어기를 설계하였다. 부하(payload)의 범위만 알고 있는 2축 자유도를 갖는 로봇 동작부에 대해서 제안된 제어 방법에 따라 제어기를 설계하여 그 성능를 확인 하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.913-916
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• 2005

In this study, an additional microstrip patch with a comb-pattern slot is positioned on the conventional single layer microstrip patch antenna. Numerical results of the antenna bandwidth and the antenna gain are increased compared with those of the conventional single layer microstrip patch antenna.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.314-316
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• 1996

본 논문에서는 슬라이딩 모드 방식을 적용한 유도 전동기와 전류제어기와 속도 제어기틀 계하였다. 제안된 제어 시스템은 로터 저항등 파라메터 변동 및 외란등에 강인한 특성을 갖는다. 슬라이딩 모드 속도 제어기에 필요한 가속도는 고이득 관측기를 이용한 추정치를 사용하여 피이킹 현상이 발생하지 않도록 제어 입력을 포화시켰다. 전동기의 속도 제어에 강인하게 작용하는 슬라이딩 모드 제어기를 설계하고 시abf레이션을 통해 그 성능을 입증했다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.902-905
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• 2006

This paper presents a new RF testing scheme based on a design-for-testability (DFT) method for measuring functional specifications of RF integrated circuits (IC). The proposed method provides input impedance. gain, noise figure. input voltage standing wave ratio (VSWR) and output signal-to-noise ratio (SNR) of a low noise amplifier (LNA). The RF test scheme is based on theoretical expressions that produce the actual RF device specifications by output DC voltages from the DR chip.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.6
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• pp.854-862
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• 1993

All of the CMOS analog and analog-digital systems have composed with several basic circuits, and among them, a important block, the amplifier part can affect the system's performance, Therefore, according to the uses in the system, the amplifier circuit have designed as various architectures (high-gain, low-noise, high-speed circuit, etc...). In this paper, we have proposed a new CMOS differential amplifier circuit. This circuit is differential to single ended input stage comprised of CMOS complementary gain circuits having internally biasing configurations. These architectures can be achieved the high gain and reduced the transistors for biasing. As a results of SPICE simulation with the standard $1.5{\mu}m$ processing parameter, the gain of the proposed circuit have a doubly value of the typical circuit's while maintaining other characteristics(phase margin, offset, etc...). And the proposed circuit is applicated in a simple CMOS comparator which has the settling time in 7nsec(CL=1pF) and the igh output swing $({\pm}4.5V)$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1139-1147
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• 2011

In this paper, a design and fabrication of GaN power amplifier for the S-band frequency (400 MHz bandwidth) are presented. A combining path using ${\lambda}$/4 transmission line is implemented for GaN pallet amp. Both the combiner with suspended-type transmission structure for low-loss and the suspended stripline coupler with aperture coupling for auto gain control are realized for achieving high-power high-efficiency amplifier. Proposed power amplifier demonstrated a 5 kW peak output power, 27.8 % efficiency, 67 dB gain without ALC and a 4 kW peak output power, 25.5 % efficiency, 0.1 dB droop at 200 usec pulse width and 10 % duty with ALC.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.257-264
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• 2007

In this paper, we have designed and fabricated a wide-band and high gain antenna which can integrate a standard of IEEE 802.1la$(5.15\sim5.25\;GHz,\;5.25\sim5.35\;GHz,\;5.725\sim5.825\;GHz)$. We inserted a parallel dual slot into a rectangular patch to have wide-band, and we offset an element of capacitance from the slot by using coaxial probe feeding method. We also designed a converter of $\lambda_g/4$ impedance with taper type line so that wide-band impedance can be matched easily. We finally designed structure with $2\times2$ array in order to improve the antenna gain, and the final fabricated antenna could have a good return loss(Return loss$\leq$-10 dB) and a high gain(over 13 dBi) at the range of $5.01\sim5.95\;GHz(B/W\doteqdot940\;MHz)$.