• Journal of Information Display
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• 제5권3호
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• pp.1-7
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• 2004

We developed a novel frame interpolation method to interpolate a frame between two successive original frames. Using this method, we are able to apply a double-rate driving method instead of an impulse driving method where a black frame is inserted between two successive original frames. The double-rate driving method enables amelioration of the motion blur of LCDs caused by the characteristics of human vision without reducing the luminosity of the whole screen. The image quality of the double-rate driving method was also found to be better than that of an impulse driving method using our motion picture simulator and an actual panel. Our initial model of our frame interpolation method consists of motion estimation with a maximum matching pixel count estimation function, an area segmentation technique, and motion compensation with variable segmentation threshold. Although salt and pepper noise remained in a portion of an object mainly due to inaccuracy of motion estimation, we verified the validity of our method and the possibility of improvement in hold-type motion blurring.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.570-574
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• 2003

In most boundary estimation algorithms estimation in EIT (Electrical Impedance Tomography), anomaly boundaries can be expressed with Fourier series and the unknown coefficients are estimated with proper inverse algorithms. Furthermore, the number of anomalies is assumed to be available a priori. The prior knowledge on the number of anomalies may be unavailable in some cases, and we need to determine the number of anomalies with other methods. This paper presents an algorithm for the boundary estimation in EIT (Electrical Impedance Tomography) using the prior information from the conventional Newton-Raphson method. Although Newton-Raphson method generates so poor spatial resolution that the anomaly boundaries are hardly reconstructed, even after a few iterations it can give general feature of the object to be imaged such as the number of anomalies, their sizes and locations, as long as the anomalies are big enough. Some numerical experiments indicate that the Newton-Raphson method can be used as a good predictor of the unknown boundaries and the proposed boundary discrimination algorithm has a good performance.

• 한국멀티미디어학회논문지
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• 제18권10호
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• pp.1205-1215
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• 2015

Efficient multi-view coding techniques are needed to reduce the complexity of multi-view video which increases in proportion to the number of cameras. To reduce the complexity and maintain image quality and bit-rates, an motion estimation method and temporal prediction structure are proposed in this paper. The proposed motion estimation method exploits the characteristic of motion vector distribution and the motion direction and motion size of the block to place search points and decide the search patten adaptively. And the proposed prediction structure divides every GOP to decide the maximum index of hierarchical B layer and the number of pictures of each B layer. Experiment results show that the complexity reduction of the proposed temporal prediction structure and motion estimation method over hierarchical B pictures prediction structure and TZ search method which are used in JMVC(Joint Multi-view Video Coding) reference model can be up to 45∼70% while maintaining similar video quality and bit rates.

• 한국멀티미디어학회논문지
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• 제17권7호
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• pp.797-805
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• 2014

In this paper we propose a new frame rate up conversion scheme which is used to overcome the motion blur problem of liquid crystal display caused by its slow response. The conventional bilateral motion estimation method which is mainly used in the frame rate up conversion scheme has a drawback that it cannot find true motion vector if there are blocks with simple texture in the search range. To solve this problem, a texture adaptive bilateral motion estimation method that increases cost value of block with simple texture is proposed. Also a motion estimation scheme that utilizes neighboring motion vector effectively is proposed to reduce computation time required to estimate motion. Since the proposed scheme does not apply all available motion vectors within the search range, the execution time of frame rate up conversion can be reduced dramatically. Experimental results show that the interpolated frame image quality of the proposed method is improved in subjective as well as objective view point compared with that of the conventional method.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.257-262
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• 2000

현재 인터넷을 활용한 웹에서의 원격 교육평가시스템은 많이 나와있으나, 학생 개개인의 특성과 성향을 고려하지 못하고 일괄적이고 전체적인 평가만을 실시하고 있는 실정이다 본 논문은 문제은행 데이터베이스를 구축하여 웹을 통해 학생이 시간과 장소의 제약 없이 평가를 실시할 수 있는 비동기 분배 커뮤니케이션(Distributed Asynchronous Communication)방법의 교육모델에 덧붙여서, 기존의 원격 교육평가 시스템에서는 소홀히 다루었던 학생의 개인차와 특성을 고려한 사용자 프로파일을 이용하여 문제를 필터링한 후 출제하여 평가의 질적인 향상 및 학생의 학력을 향상시키는 효과적인 방법을 제시한다. 이것은 DAC 방식을 발전시킨 적응력 있는 DAC 방식이라 한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 추계학술대회
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• pp.493-496
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• 2010

본 논문에서는 주행중인 차량의 CO2 배출량을 추정하기 위한 방법들로, 주행거리에 따른 CO2 배출량 추정 방법, IPCC에 따른 CO2 배출량 추정 방법, MAF와 화학반응식을 이용한 CO2 배출량 추정 방법 등에 대해서 설명하고 각각의 방법들의 성능을 비교하기 위해 실차(제네시스 3.3)를 이용하여 약 5Km의 실제 도로 경로를 주행하며 각각의 CO2 추정 방법들에 대한 성능을 실증 분석하였다.

• 정보처리학회논문지B
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• 제10B권7호
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• pp.811-814
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• 2003

본 논문에서는 십자패턴과 육각패턴을 이용한 고속 블록 정합 동작 예측 기법을 제안한다. 블록 기반 탐색에서 전역 탐색방법이 가장 좋은 동작벡터를 찾지만, 탐색영역 내의 모든 전을 검색하기 때문에 많은 시간을 필요로 하게 된다. 본 방법은 대부분의 동영상에서 동작벡터가 블록의 중심 부근에 집중적으로 분포함을 착안하여 십자패턴으로 중앙을 우선 탐색한 다음 움직임이 큰 동작벡터를 육각패턴을 사용하여 찾는다. 실험결과, 본 방법은 기존의 탐색방법보다 화질과 탐색시간에서 대부분의 경우에 좋은 성능을 보임을 알 수 있다.

• Journal of Power Electronics
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• 제17권1호
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• pp.149-160
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• 2017

To improve the performance of sensorless induction motor (IM) drives, an adaptive speed estimation method based on a strong tracking extended Kalman filter with a least-square algorithm (LS-STEKF) for induction motors is proposed in this paper. With this method, a fading factor is introduced into the covariance matrix of the predicted state, which forces the innovation sequence orthogonal to each other and tunes the gain matrix online. In addition, the estimation error is adjusted adaptively and the mutational state is tracked fast. Simultaneously, the fading factor can be continuously self-tuned with the least-square algorithm according to the innovation sequence. The application of the least-square algorithm guarantees that the information in the innovation sequence is extracted as much as possible and as quickly as possible. Therefore, the proposed method improves the model adaptability in terms of actual systems and environmental variations, and reduces the speed estimation error. The correctness and the effectiveness of the proposed method are verified by experimental results.

• ETRI Journal
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• 제42권3호
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• pp.324-332
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• 2020

In this paper, a blind symbol timing offset (STO) estimation method is proposed for offset quadrature phase-shift keying (OQPSK) modulated signals, which also works for other linearly modulated signals (LMS) such as binary-PSK, QPSK, 𝜋/4-QPSK, and minimum-shift keying. There are various methods available for blind STO estimation of LMS; however, none work in the case of OQPSK modulated signals. The popular cyclic correlation method fails to estimate STO for OQPSK signals, as the offset present between the in-phase (I) and quadrature (Q) components causes the cyclic peak to disappear at the symbol rate frequency. In the proposed method, a set of close and approximate offsets is used to compensate the offset between the I and Q components of the received OQPSK signal. The STO in the time domain is represented as a phase in the cyclic frequency domain. The STO is therefore calculated by obtaining the phase of the cyclic peak at the symbol rate frequency. The method is validated through extensive theoretical study, simulation, and testbed implementation. The proposed estimation method exhibits robust performance in the presence of unknown carrier phase offset and frequency offset.

• 제어로봇시스템학회논문지
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• 제14권9호
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• pp.916-924
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• 2008

In this paper dynamic modeling parameters were estimated using a frequency domain estimation method. A systematic flight test method was employed using preprogrammed multistep excitation of the swashplate control input. In addition when one axis is excited, the autopilot is engaged in the other axis, thereby obtaining high-quality flight data. A dynamic model was derived for a small scale unmanned helicopter (CNUHELI-020, developed by Chungnam National University) equipped with a Bell-Hiller stabilizer bar. Six degree of freedom equations of motion were derived using the total forces and moments acting on the small scale helicopter. The dynamics of the main rotor is simplified by the first order tip-path plane, and the aerodynamic effects of fuselage, tail rotor, engine, and horizontal/vertical stabilizer were considered. Trim analysis and linearized model were used as a basic model for the parameter estimation. Doublet and multistep inputs are used to excite dynamic motions of the helicopter. The system and input matrices were estimated in the frequency domain using the equation error method in order to match the data of flight test with those of the dynamic modeling. The dynamic modeling and the flight test show similar time responses, which validates the consequence of analytic modeling and the procedures of parameter estimation.