• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.1083-1088
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• 2003

This paper presents three algorithms of repetitive controller for compensation of the repeatable uncut in hard disk drive. The basic theory of the repetitive controller and the analysis of the disturbance in hard disk drive are introduced. The tracking controller is designed in order to design the "plug-in type" repetitive controller. Design of the repetitive controller is considered as the design of the filter, determination of Gain and design of additional compensation for the various types. Specially, trade-off relationship between stability and performance is important factor for the design. The thee kinds of "plug-in type" repetitive controllers are designed simulated and experimented. Performance and characteristic of them are compared by the analysis of the experimental results

• 한국소음진동공학회논문집
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• 제15권9호
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• pp.1045-1052
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• 2005

Tn this paper. dual rotor disk configuration with a coreless stator is proposed for the Lorentz force type integrated motor hearing system. An experimental compensation for the effects of high order harmonics is performed using the digital controller of the experimental setup. The runout profile and rotor unbalance are also identified by the extended influence coefficient method. The experimental results confirm that this compensation scheme effectively attenuates the rotor vibration all over the operating range of rotational speed.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.995-998
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• 2005

본 논문에서는 시스템 온 칩 (SoC, System-on-Chip) 트랜시버에 적용이 가능하며. 저잡음 증폭기(LNA, Low Noise Amplifier)를 위한 자동 보상 회로 (ACC, automatic compensation circuit)를 제안한다. 개발된 회로는 고주파 내부 자체 검사 (BIST, Built-In Self-Test) 회로, 커패시터 미러 뱅크 (CMB, Capacitor Mirror Banks)와 디지털 처리장치로 구성되어 있다. 자동 보상 회로는 LNA가 정상 동작을 하지 않을 때 SoC 트랜시버의 구성요소인 디지털 프로세서를 이용하여 LNA가 정상 동작을 하도록 자동적으로 조정하는 역할을 한다.

• 한국정보통신학회논문지
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• 제17권12호
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• pp.2793-2799
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• 2013

본 논문에서는 시간에 따라 변하는 잡음 환경에 강인한 음성 인식을 위해 효과적인 특징 보상 기법을 제안한다. 제안하는 기법에서는 기존의 Variational 모델 생성 기법의 모델 정확도를 향상시키고자 PCA를 도입한다. 제안된 기법은 다중 모델을 사용하는 PCGMM 기반의 특징 보상에 적용된다. 실험 결과는 제안한 PCA 기반의 Variational 모델 생성 기법이 배경 음악 환경의 다양한 SNR 조건에서 기존의 전처리 기법에 비하여 음성 인식 성능을 향상 시키는데 우수함을 입증한다. 제안한 모델 생성 기법이 기존의 Variational 모델 생성 방법에 비해 배경 음악 환경에서 평균 12.14%의 상대적 인식 성능 향상률을 나타낸다.

• ETRI Journal
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• 제30권5호
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• pp.753-755
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• 2008

In this letter, we propose a new histogram equalization technique for feature compensation in speech recognition under noisy environments. The proposed approach combines a signal-to-noise-ratio-dependent feature reconstruction method and the class histogram equalization technique to effectively reduce the acoustic mismatch present in noisy speech features. Experimental results from the Aurora 2 task confirm the superiority of the proposed approach for acoustic feature compensation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.831-836
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• 1990

Real-time implementations of active noise controller are proposed and tested. For compensation of time delay of feed-back path, the n-step ahead prediction is applied. And predicting source noise and reflection noise respectively, reflection noise can be cancelled. For real-time processing, the DSP56001(Digital Signal Processor) is used. Experimental results show that the proposed controller is stable and of good performance.

• ETRI Journal
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• 제34권4호
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• pp.518-526
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• 2012

This paper proposes LC voltage-controlled oscillator (VCO) phase-locked loop (PLL) and ring-VCO PLL topologies with low-phase noise. Differential control loops are used for the PLL locking through a symmetrical transformer-resonator or bilaterally controlled varactor pair. A differential compensation mechanism suppresses out-band spurious tones. The prototypes of the proposed PLL are implemented in a CMOS 65-nm or 45-nm process. The measured results of the LC-VCO PLL show operation frequencies of 3.5 GHz to 5.6 GHz, a phase noise of -118 dBc/Hz at a 1 MHz offset, and a spur rejection of 66 dBc, while dissipating 3.2 mA at a 1 V supply. The ring-VCO PLL shows a phase noise of -95 dBc/Hz at a 1 MHz offset, operation frequencies of 1.2 GHz to 2.04 GHz, and a spur rejection of 59 dBc, while dissipating 5.4 mA at a 1.1 V supply.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.183-186
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• 1999

The Ultra-miniature and low phase noise Colpitts VCO of 0.06㏄ in size has been developed using the high Q resonator and phase compensation technique. This type is one transistor VCO without a buffer. To design and simulate the VCO accurately, nolinear model parameters of a bipolar transistor are extracted using the measured I-V data and S parameters based on the Gummel-Poon model. Design and simulation have been done by Serenade 7.5 design tool using the extracted nonlinear model parameters. The wideband VCO has been designed using two varactor diodes and open loop gain compensation technique to improve the operating frequency range. The ultra-miniature VCO has shown the phase noise of -91㏈c/Hz at 10KHz offset and output power of -3㏈m The wideband VCO has shown the tuning frequency bandwidth of 150MHz phase noise of -95㏈c/Hz at 10KHz offset and output power of 5㏈m.

• 음성과학
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• 제10권3호
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• pp.263-277
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• 2003

One of major problems in speech recognition is performance degradation due to the mismatch between the training and test environments. Recently, Stereo-based Piecewise LInear Compensation for Environments (SPLICE), which is frame-based bias removal algorithm for cepstral enhancement using stereo training data and noisy speech model as a mixture of Gaussians, was proposed and showed good performance in noisy environments. In this paper, we propose several methods to improve the conventional SPLICE. First we apply Cepstral Mean Subtraction (CMS) as a preprocessor to SPLICE, instead of applying it as a postprocessor. Secondly, to compensate residual distortion after SPLICE processing, two-stage SPLICE is proposed. Thirdly we employ phonetic information for training SPLICE model. According to experiments on the Aurora 2 database, proposed method outperformed the conventional SPLICE and we achieved a 50% decrease in word error rate over the Aurora baseline system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.520-524
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• 2002

Multi-reference, scan-based Acoustical Holography is a useful measurement technique when insufficient microphones are available to measure a complete hologram at once. When the sound sources are stationary, the whole hologram can be constructed by joining together sub-holograms captured using a relatively small scan array. Here that approach is extended by the development of a formulation that explicitly includes the acoustical transfer functions between the reference microphones and the scanning microphones. Based on those expressions, a compensation procedure of spectral variance due to source-non-stationarity is proposed. It has been verified both numerically and experimentally that this procedure can help suppress spatially distributed noise caused by the source level non-stationarity that is always present in a measurement.