• Title/Summary/Keyword: Adaptive bias

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An Effective TOA-based Localization Method with Adaptive Bias Computation

  • Go, Seung-Ryeol
    • Journal of IKEEE
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    • v.20 no.1
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    • pp.1-8
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    • 2016
  • In this paper, we propose an effective time-of-arrival (TOA)-based localization method with adaptive bias computation in indoor environments. The goal of the localization is to estimate an accurate target's location in wireless localization system. However, in indoor environments, non-line-of-sight (NLOS) errors block the signal propagation between target device and base station. The NLOS errors have significant effects on ranging between two devices for wireless localization. In TOA-based localization, finding the target's location inside the overlapped area in the TOA-circles is difficult. We present an effective localization method using compensated distance with adaptive bias computation. The proposed method is possible for the target's location to estimate an accurate location in the overlapped area using the measured distances with subtracted adaptive bias. Through localization experiments in indoor environments, estimation error is reduced comparing to the conventional localization methods.

High PAE Power Amplifier Using Adaptive Bias Control Circuit for Wireless Power Transmission (적응형 바이어스 조절 회로를 사용한 무선에너지 전송용 고효율 전력증폭기)

  • Hwang, Hyunwook;Seo, Chulhun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.10
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    • pp.43-46
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    • 2012
  • In this paper, high efficiency power amplifier is implemented with high gain amplifier. Two-stage amplifier using adaptive bias control circuit improve efficiency at low input power. Fixed bias circuit and adaptive bias circuit both have about 76 % efficiency at maximum power level. However amplifier using an adaptive bias control circuit has 70 % at 6 dBm input power level when the amplifier using fixed bias circuit has 50%. The proposed power amplifier using the adaptive bias control circuit can have high efficiency at lower power level.

Research on PAE and Linearity of Doherty Amplifier Using Adaptive Bias and PBG Structure (적응형 바이어스와 PBG를 이용한 Doherty 전력 증폭기 전력효율과 선형성 개선에 관한 연구)

  • Lee Wang-Yeol;Seo Chul-Hun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.8 s.99
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    • pp.777-782
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    • 2005
  • In this paper, adaptive bias circuit and PBG structure have been employed to suppress IMD(Inter-Modulation Distortion) and improve PAE(Power Added Efficiency) of the Doherty amplifier. Gate bias voltage has been controlled with the envelope of the input RF signal and PBG structure has been employed on the output port of Doherty amplifier. The proposed power amplifier using adaptive bias circuit and PBG has been improved the $IMD_3$ by 7.5 dBc, and the average PAR by $12\%$, respectively.

Design of High Efficiency Power Amplifier Using Adaptive Bias Technique and DGS (적응형 바이어스기법과 DGS를 이용한 고효율 전력증폭기설계)

  • Oh, Chung-Gyun;Son, Sung-Chan
    • 한국정보통신설비학회:학술대회논문집
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    • 2008.08a
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    • pp.403-408
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    • 2008
  • In this paper, the high efficiency and linearity Doherty power amplifier using DGS and adaptive bias technique has been designed and realized for 2.3GHz WiBro applications. The Doherty amplifier has been implemented us-ing silicon MRF 281 LDMOS FET. The RF performances of the Doherty power amplifier (a combination of a class AB carrier amplifier and a bias-tuned class C peaking amplifier) have been compared with those of a class AB amplifier alone, and conventional Doherty amplifier. The Maximum PAE of designed Doherty power amplifier with DGS and adaptive bias technique has been 36.6% at 34.01dBm output power. The proposed Doherty power amplifier showed an improvement 1dB at output power and 7.6% PAE than a class AB amplifier alone.

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Design of High Efficiency Doherty Power Amplifier Using Adaptive Bias Technique for Wibro Applications (적응형 바이어스 기법을 이용한 와이브로용 고효율 도허티 전력증폭기 설계)

  • Oh, Chung-Gyun;Choi, Jae-Hong;Koo, Kyung-Heon
    • Journal of Advanced Navigation Technology
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    • v.9 no.2
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    • pp.164-169
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    • 2005
  • In this paper, the high efficiency Doherty power amplifier using adaptive bias technique has been designed and realized for 2.3GHz Wibro applications. The RF performances of the Doherty power amplifier using adaptive bias technique have been compared with those of a class AB amplifier alone, and conventional Doherty amplifier. The Maximum PAE of designed Doherty power amplifier with adaptive bias technique has been 36.6% at 34.0dBm output power. The proposed Doherty power amplifier showed an improvement 1dB at output power and 7.6% PAE than a class AB amplifier alone.

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Research on PAE and Linearity of Power Amplifier Using Adaptive Bias and PBG Structure (적응형 바이어스와 PBG를 이용한 전력증폭기 전력효율과 선형성 개선에 관한 연구)

  • Cho Sunghee;Seo Chulhun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.2 s.332
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    • pp.87-92
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    • 2005
  • In this paper, adaptive bias circuit and PBG structure have been employed to suppress IMD and improve PAE (Power Added Efficiency) of the power amplifier. It is controlling the gate 'dc' bias voltage with the envelope of the input RF signal. and The PBG structure has been employed on the output port of power amplifier . The proposed power amplifier using adaptive bias circuit and PBG has been improved the IMG by 3 dBc, and the average PAE by $35.54\%$, respectively.

Selection of Data-adaptive Polynomial Order in Local Polynomial Nonparametric Regression

  • Jo, Jae-Keun
    • Communications for Statistical Applications and Methods
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    • v.4 no.1
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    • pp.177-183
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    • 1997
  • A data-adaptive order selection procedure is proposed for local polynomial nonparametric regression. For each given polynomial order, bias and variance are estimated and the adaptive polynomial order that has the smallest estimated mean squared error is selected locally at each location point. To estimate mean squared error, empirical bias estimate of Ruppert (1995) and local polynomial variance estimate of Ruppert, Wand, Wand, Holst and Hossjer (1995) are used. Since the proposed method does not require fitting polynomial model of order higher than the model order, it is simpler than the order selection method proposed by Fan and Gijbels (1995b).

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Temperature-Adaptive Back-Bias Voltage Generator for an RCAT Pseudo SRAM

  • Son, Jong-Pil;Byun, Hyun-Geun;Jun, Young-Hyun;Kim, Ki-Nam;Kim, Soo-Won
    • ETRI Journal
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    • v.32 no.3
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    • pp.406-413
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    • 2010
  • In order to guarantee the proper operation of a recessed channel array transistor (RCAT) pseudo SRAM, the back-bias voltage must be changed in response to changes in temperature. Due to cell drivability and leakage current, the obtainable back-bias range also changes with temperature. This paper presents a pseudo SRAM for mobile applications with an adaptive back-bias voltage generator with a negative temperature dependency (NTD) using an NTD VBB detector. The proposed scheme is implemented using the Samsung 100 nm RCAT pseudo SRAM process technology. Experimental results show that the proposed VBB generator has a negative temperature dependency of -0.85 $mV/^{\circ}C$, and its static current consumption is found to be only 0.83 ${\mu}A$@2.0 V.

The Necessity of Independent Data Monitoring Committee in Domestic Clinical Trials (현재 국내임상시험에서 독립적 자료모니터링위원회의 필요성)

  • Kang, Seung-Ho
    • The Korean Journal of Applied Statistics
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    • v.22 no.2
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    • pp.317-327
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    • 2009
  • In adaptive designs important components of clinical trials may be changed based on the results of interim analysis. Several international guidelines point out that such interim analysis should be performed by independent experts who do not participate in clinical trials when adaptive designs are used in therapeutic confirmatory clinical trials, and if not, it may cause bias. The international guidelines recommend the establishment of independent data monitoring committee for conducting interim analysis independently.

Biased Zero-Error Probability for Adaptive Systems under Non-Gaussian Noise (비-가우시안 잡음하의 적응 시스템을 위한 바이어스된 영-오차확률)

  • Kim, Namyong
    • Journal of Internet Computing and Services
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    • v.14 no.1
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    • pp.9-14
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    • 2013
  • The criterion of zero-error probability provides a limitation on error probability functions being used for adaptive systems when the error samples are shifted by the influence of DC-bias noise. In this paper, we employ a bias term in the error distribution and propose a new criterion of the biased zero-error probability with error being zero. Also, by maximizing the proposed criterion on expanded filter structures, a supervised adaptive algorithm has been derived. From the simulation results of supervised equalization, the algorithm based on the proposed criterion yielded zero-centered and highly concentrated error samples without disturbance in the environments of strong impulsive and DC-bias noise.