• 전기학회논문지
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• 제63권7호
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• pp.950-955
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• 2014

In this paper, we propose a drug treatment protocol for the three state HIV infection model that explicitly includes the concentration of healthy T cells, infected T cells, and HIV. While most of the previous methods are not able to achieve the treatment goal in the presence of modelling errors, the proposed method is designed so as to compensate for the model uncertainties. Based on the Jacobain linearization of nonlinear HIV infection model, disturbance observer(DOB) based control is employed to design the drug treatment for the HIV patients. Computer simulation is carried out for nonlinear model in order to compare the performance of the proposed method with that of the conventional technique. The simulation results show that, in the presence of parameter uncertainties, the substantial improvement in the performance can be achieved by the proposed DOB controller.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.147-150
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• 2007

This paper presents an advanced RFID reader system implementing multi-protocols and multi-standards at 900MHz. In accordance with the strict regulations specified by ISO 18000-6 B-Type and EPC Global Gen 2, we have designed corresponding systemic factors which meet the domestic radio frequency utilizing bands of 910-914MHz. In addition, we develop numerous crucial factors of system compatibility options including SSB (Single-Side Band) and DSB (Double-Side Band) specifications, also OOK (On-Off Keying), ASK (Amplitude Shift Keying) and PR-ASK (Phase Reversed-Amplitude Shift Keying) modulation formula. Remarkable technical features of system in this paper can be the direct conversion routines using I/Q Modulation/Demodulation respectively, and Full-Duplex formulation operating at identical frequency bands.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.241-246
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• 2016

This paper presents a method that can improve the performance of permanent magnet synchronous motor current control by minimizing the measured current phase delay caused by the Low Pass Filter(LPF) used to cut off the noises that flowed in when feedback currents are measured. Although existing methods that change the Cutoff Frequency of the LPF can minimize phase delays during high speed rotations, their noise cutoff effects are much lower and this may lead to the decline of control performance. Therefore, in this study, an algorithm that can compensate current phase delays through relatively simple calculations from the synchronous motor d-q axis coordinate transformation matrix and the inverse transformation matrix is proposed and the validity of the proposed method is verified by comparing the waveform of the calculated current with the waveform of actual currents through simulations and experiments.

• 전기학회논문지
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• 제62권9호
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• pp.1264-1269
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• 2013

In this paper, we study a disturbance observer (DOB) based controller for an EMS(Electro-Magnetic Suspension) system in presence of mass uncertainty and input disturbance. The DOB based controller is employed in order to compensate the modeling uncertainty and attenuate disturbance signals. For the design of DOB based controller, the Jacobain linearization of nonlinear system model equation is used. Computer simulation is carried out for nonlinear model in order to compare the performance of the proposed DOB controller with that of the conventional PID controller. The simulation results show that the substantial improvement in the performance can be achieved by the proposed DOB controller.

• 전기학회논문지
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• 제66권5호
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• pp.812-818
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• 2017

In this paper, we design a reduced-order disturbance observer (DOB) controller for an EMS (Electro-Magnetic Suspension) system with mass uncertainty. Compared with conventional DOB controller, the proposed reduced-order DOB controller can be implemented in a simpler way, since it uses reduced order nominal model and Q-filter. It is shown that the nominal model for the proposed DOB controller should be carefully chosen in order to achieve the robust stability in the present of mass uncertainty. Computer simulation results to validate the effectiveness of the proposed DOB controller are included.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.993-996
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• 2001

In the composition of 0.16BaO-0.15(Nd$\_$0.87/,Bi$\_$0.13/)$_2$O$_3$-0.69TiO$_2$$.$Glass [EG-2782] 3wt% addition sintered at 1080$^{\circ}C$, we could obtained microwave properties of dielectric constant $\varepsilon$$\_$r/= 80.1, quality factor Q ${\times}$ f = 810 (at 3.5 GHz]) and temperature coefficient of resonant frequency $\tau$$\_$f/ = -1.3 [ppm/$^{\circ}C$]

• 산업기술연구
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• 제29권B호
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• pp.101-105
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• 2009

A 1.571GHz LC VCO with optimized spiral inductor for GPS receiver is designed in 130nm CMOS process. The phase noise of the VCO has been reduced the use of high Q inductor and on chip filter. It has phase noise of -91dBc/Hz, -111dBc/Hz, and -131dBc/Hz at 10kHz, 100kHz, and 1MHz offset frequencies from the carrier, respectively. This VCO consumes 2mA from a 0.6V supply.

• 대한전자공학회논문지
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• 제21권4호
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• pp.37-42
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• 1984

전송속도가 9600bps인 고속 data modem에서 효과적인 symbol timing 회로의 구성방식이 제시되었다. Symbol timing 회로에 소요되는 계산량을 줄이기 위한 방식 및 그것이 수신기의 mean square error(MSE)에 미치는 영향이 제시되었고 timing wave의 통계적 특성에 대한 이론적인 전개가 행하여졌다. Digital Phase-looted loop(DPLL)에 의해서 timing wave의 side tone 성분을 억제할 수 있음을 보였고 computer simulation에 의해서 송신기의 symbol 주파수를 변화시켰을 경우 1차 DPLL과 2차 DPLL의 동작이 비교되었다.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.3-6
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• 2002

In this paper, Thin film bulk acoustic resonate.(TFBAR) fillers tuned by gold plated on-wafer inductors are presented. The air-gap type TEBAR is used with aluminum nitride(AIN) as piezoelectric material and platinum as top and bottom electrodes. Inductor equivalent model and modified Butterworth-Van Dyke(MBVD) model are employed for the frequency tuning of fabricated TFBAR bandpass filters. Fabricated inductor has inductance of 3 nH and Q factor of about 8 at 2 ㎓. It is clearly revealed that inductor tuning can enhance the bandwidth of ladder filters and improve out-of-band rejection characteristic around 10㏈.

• 한국음향학회지
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• 제20권8호
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• pp.81-87
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• 2001

The human auditory system is appropriate for the "constant Q"system. The STFT (Short Time Fourier Transform) is not suitable for the auditory perception model since it has constant bandwidth. In this paper, the CWT (continuous wavelet transform) is employed for the auditory filter model. In the CWT, the frequency resolution can be adjusted for auditory sensation models. The proposed CWT is applied to the modeling of the JNVF. In addition, other signal processing methods such as STFT, VER-FFT and VFR-STFT are discussed. Among these methods, the model of JNVF (Just Noticeable Variation in Frequency) by using the CWT fits in with the JNVF of auditory model although it requires quite a long time.