• Title/Summary/Keyword: Nonlinear gain

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The Effect of Organic Acids in Decontamination Solution on Ion Exchange of Metal Ions (제염용액내 유기산이 금속이온 이온교환에 미치는 영향)

  • Yang, Yeong-Seok;Kang, Young-Ho;Jheong, Gyeong-Rak
    • Applied Chemistry for Engineering
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    • v.4 no.1
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    • pp.171-177
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    • 1993
  • In decontamination process to remove radioactive materials of reactor cooling system, the metal ions dissolved by organic acids in decontamination solution are separated by use of ion exchange resin in the column. However, organic acids in decontamination solution decrease the apparent affinity of the resin to metal ions. In light of this, some experiments were carried out on the Amberlite IRN-77 cation resin with cobalt and iron to gain a better understanding of the complexation effects on the ion exchange process. Experimental results showed that EDTA among organic acids used as chemical decontaminants predominantly caused reduction of ion exchange capacity of cobaltous ion to resin since this reagent formed the complex with the cobaltous ion stronger than that with the ferrous ion. In contrast, the effects of oxalic acid and citric acid were found to be negligible. And, single and two-component nonlinear equilibrium relationships of the metal ions were established using experimental data.

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Satellite Data Link Waveform and Transponder Structure for Anti-Jamming (항재밍을 위한 위성데이터링크 웨이브폼 및 중계기 구조)

  • Kim, Ki-Keun;Lee, Min-Woo;Lim, Jae-Sung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.12B
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    • pp.1728-1735
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    • 2011
  • In this paper, satellite data link waveform is proposed which is based on the waveform of Link-16 but LDPC code is studied instead of CCSK code in order to be optimized to satellite nonlinear channel environment and transmission characteristics. And the DSM (Demux, Selective CH switch, and Mux) transponder structure is suggested which can remove all of the jamming signal out of the transmission signal band and convert uplink hopping frequency to desired ones of downlink. The results of BER and anti-jamming performance analysis shows that the required Eb/No and processing gain in the worst case partial band jammer of the proposed waveform are 2.5dB and 52dB respectively and the anti-jamming capacity improvement of DSM transponder is maximum 2dB.

A Novel Carrier Leakage Suppression Scheme for UHF RFID Reader (UHF 대역 RFID 리더 반송파 누설 억압 연구)

  • Jung, Jae-Young;Park, Chan-Won;Yeom, Kyung-Whan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.4
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    • pp.489-499
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    • 2011
  • RFID technologies, which allow collecting, storing, processing, and tracking information by wirelessly recognizing the inherent ID of object through an attached electronic tag, have a variety of application areas. This paper presents a novel carrier leakage suppression RF(CLS-RF) front-end for ultra-high-frequency RF identification reader. The proposed reader CLS-RF front-end structure generates the carrier leakage replica through the nonlinear path that contains limiter. The limiting function only preserves the frequency and phase information of the leakage signal and rejects the amplitude modulated tag signal in the envelope. The carrier leakage replica is then injected into the linear path that contains phase shifter. Therefore, the carrier leakage signal is effectively cancelled out, while not affecting the gain of the desired tag backscattering signal. We experimentally confirm that the prototype shows a significant improvement in the leakage to signal ratio by up to 36 dB in 910 MHz, which is consistent with our simulation results.

Characteristics of the Nd:YAG laser with stimulated brillouin scattering phase conjugate mirror (유도 브릴루앙 산란 위상공액 거울을 이용한 Nd:YAG 레이저 발진기의 출력특성)

  • 이동원;이성구;박승현;공홍진
    • Korean Journal of Optics and Photonics
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    • v.13 no.6
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    • pp.548-553
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    • 2002
  • We have investigated the output characteristics of a Nd:YAG oscillator with a Stimulated Brillouin Scattering phase conjugation mirror (SBS-PCM). FC-75 is used as an SBS gain medium and Cr:YAG (T=50%) as a Q-switcher. The SBS-PCM consists of an SBS-cell and a simple plano-convex focusing lens system. For the case of not using a Q-switcher, an SBS-cell doesn't work as a phase conjugation mirror. For the case of using a Q-switcher, the energy characteristics remains nearly the same whether using the SBS-cell or not using it. The pulse width is reduced from 50 ns to 40 ns by an SBS-PCM. When the SBS-cell is used with a Q- switcher, the SBS-cell works very well as a phase conjugation mirror and its beam-profile is improved dramatically. And in order to explain the progression of beam-profile, we propose a simple model based on the nonlinear reflectivity of the SBS-PCM, whose reflectivity is dependent on the pumping intensity at the focal plane.

Design and Demonstration of All-Optical XOR, AND, OR Gate in Single Format by Using Semiconductor Optical Amplifiers (반도체 광증폭기를 이용한 다기능 전광 논리 소자의 설계 및 측정)

  • Son, Chang-Wan;Yoon, Tae-Hoon;Kim, Sang-Hun;Jhon, Young-Min;Byun, Yung-Tae;Lee, Seok;Woo, Deok-Ha;Kim, Sun-Ho
    • Korean Journal of Optics and Photonics
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    • v.17 no.6
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    • pp.564-568
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    • 2006
  • Using the cross-gain modulation (XGM) characteristics of semiconductor optical amplifiers (SOAs), multi-functional all-optical logic gates, including XOR, AND, and OR gates are successfully simulated and demonstrated at 10Gbit/s. A VPI component maker^TM simulation tool is used for the simulation of multi-functional all-optical logic gates and the10 Cbit/s input signal is made by a mode-locked fiber ring laser. A multi-quantum well (MQW) SOA is used for the simulation and demonstration of the all-optical logic system. Our suggested system is composed of three MQW SOAs, SOA-1 and SOA-2 for XOR logic operation and SOA-2 and SOA-3 for AND logic operation. By the addition of two output signals XOR and AND, all-optical OR logic can be obtained.

A 20 GHz Band 1 Watt MMIC Power Amplifier (20 GHz대 1 Watt 고출력증폭 MMIC의 설계 및 제작)

  • 임종식;김종욱;강성춘;남상욱
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.7
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    • pp.1044-1052
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    • 1999
  • A 2-stage 1 watt MMIC(Monolithic Microwave Integrated Circuits) HPA(High Power Amplifiers) at 20 GHz band has been designed and fabricated. The $0.15\mu\textrm{m}$ with the width of $400\mu\textrm{m}$for single device pHEMT technology was used for the fabrication of this MMIC HPA. Due to the series feedback technique from source to ground, bias circuits and stabilization circuits on the main microstrip line, the stability factors(Ks) are more than one at full frequency. The independent operation for each stage and excellent S11, S22 less than -20 dB have been obtained by using lange couplers. For beginning the easy design, linear S-parameters have been extracted from the nonlinear equivalent circuit in foundry library, and equivalent circuits of devices at in/output ports were calculated from this S-parameters. The measured performances, which are in well agreement with the predicted ones, showed the MMIC HPA in this paper has the minimum 15 dB of linear gain, -20 dB of reflection coefficients and 31 dBm of output power over 17~25 GHz.

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System identification of soil behavior from vertical seismic arrays

  • Glaser, Steven D.;Ni, Sheng-Huoo;Ko, Chi-Chih
    • Smart Structures and Systems
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    • v.4 no.6
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    • pp.727-740
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    • 2008
  • A down hole vertical seismic array is a sequence of instruments installed at various depths in the earth to record the ground motion at multiple points during an earthquake. Numerous studies demonstrate the unique utility of vertical seismic arrays for studying in situ site response and soil behavior. Examples are given of analyses made at two sites to show the value of data from vertical seismic arrays. The sites examined are the Lotung, Taiwan SMART1 array and a new site installed at Jingliao, Taiwan. Details of the installation of the Jingliao array are given. ARX models are theoretically the correct process models for vertical wave propagation in the layered earth, and are used to linearly map deeper sensor input signals to shallower sensor output signals. An example of Event 16 at the Lotung array is given. This same data, when examined in detail with a Bayesian inference model, can also be explained by nonlinear filters yielding commonly accepted soil degradation curves. Results from applying an ARMAX model to data from the Jingliao vertical seismic array are presented. Estimates of inter-transducer soil increment resonant frequency, shear modulus, and damping ratio are presented. The shear modulus varied from 50 to 150 MPa, and damping ratio between 8% and 15%. A new hardware monitoring system - TerraScope - is an affordable 4-D down-hole seismic monitoring system based on independent, microprocessor-controlled sensor Pods. The Pods are nominally 50 mm in diameter, and about 120 mm long. An internal 16-bit micro-controller oversees all aspects of instrumentation, eight programmable gain amplifiers, and local signal storage.

Robust Tracking and Human-Compliance Control Using Integral SMC and DOB (적분슬라이딩모드와 DOB를 이용한 강인추종 및 인간순응 로봇제어)

  • Asignacion Jr., Abner;Kim, Min-chan;Kwak, Gun-Pyong;Park, Seung-kyu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.2
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    • pp.416-422
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    • 2017
  • The robot control with safety consideration is required since robots and human work together in the same space more frequently in these days. For safety, robots must have compliance to human force and robust tracking performance with high impednace for the nonhuman disturbances. The novel idea is proposed to achieve the compliance and high impedance with one controller structure. For the compliance, the ISMC(Integral Sliding Mode Control) and HDOB(Human Disturbance Observer) The human force is identified by using the human band pass filter and its output is sent to the sliding surface. The sliding mode dynamic is affected by human disturbance and the compliance for human is achieved. The disturbances besides human frequencies are decoupled by the ISMC and the robust tracking is achieved. The additional LDOB(Low Frequency Disturbance Observer) decreases the maxim nonlinear gain and leads low chattering. The introduction of human disturbance into the sliding mode dynamic is the main novel idea of this paper.

Optimum Subband Quantization Filter Design for Image Compression (영상압축을 위한 최적의 서브밴드 양자화 필터 설계)

  • Park, Kyu-Sik;Park, Jae-Hyun
    • The KIPS Transactions:PartB
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    • v.12B no.4 s.100
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    • pp.379-386
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    • 2005
  • This paper provides a rigorous theory for analysis of quantization effects and optimum filter bank design in quantized multidimensional subband filter banks. Even though subband filter design has been a hot topic for last decades, a few results have been reported on the subband filter with a quantizer. Each pdf-optimized quantizer is modeled by a nonlinear gain-plus-additive uncorrelated noise and embedded into the subband structure. Using polyphase decomposition of the analysis/synthesis filter banks, we derive the exact expression for the output mean square quantization error. Based on the minimization of the output mean square error, the technique for optimal filter design methodology is developed. Numerical design examples for optimum nonseparable paraunitary and biorthogonal filter banks are presented with a quincunx subsampling lattice. Through the simulation, $10\~20\;\%$ decreases in MSE have been observed compared with subband filter with no quantizers especially for low bit rate cases.

Design a Path Following Line-of-Sight Guidance Law based on Vehicle Kinematics (비행체 운동 역학 기반 경로 추종 시선각 유도 법칙 설계)

  • You, Dong-Il;Shim, Hyun-Chul
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.6
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    • pp.506-514
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    • 2012
  • This paper represents a method for designing of path following Line-of-Sight(LOS) guidance law based on vehicle kinematics. In general, a LOS guidance law which is composed of gains and approach length as design parameters is designed by empirical or trial-and-error method. These approaches cannot guarantee a precision tracking performance of guidance law consistently. Also, the design parameters should be redesigned with variations of vehicle maneuverability and flight velocity. Based on a vehicle kinematics with its velocity, the proposed method for designing of parameters not only minimizes the number of design parameters, also has a reliable and consistent tracking performance using variable guidance gain changed in accordance with flight velocity. This is validated by nonlinear simulation with $1^{st}$ order attitude response dynamics and flight experiments with given linear and circular path.