• 한국정보통신학회논문지
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• 제20권3호
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• pp.506-512
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• 2016

최근 에너지 하베스팅 기술은 배터리 용량 부족 문제를 해결하여 네트워크 수명을 향상시킬 수 있는 방안으로 관심을 받고 있다. 하지만 기존 연구의 경우 정확한 채널정보를 바탕으로 한 이상적인 환경에서의 하베스팅 기술만을 고려하였다. 본 논문에서는 채널 추정 절차와 이에 따른 채널 추정 오차를 반영한 현실적 에너지 하베스팅 네트워크 환경에서 에너지 효율성을 향상시키기 위한 자원 할당 기법을 제안한다. 제안 기법에서는 최적화 기법을 이용하여 시스템 데이터 전송률, 에너지 획득량, 불완전한 채널 추정 특성 등을 동시에 고려한 스케줄링 및 파워 할당 해를 찾는다. 제안 기법은 에너지 효율성 관점에서 기존의 하베스팅 기법보다 향상된 성능을 보이며, 채널 추정 오차가 반영되었을 때의 에너지 효율적 자원할당 방법에 대한 새로운 정보를 제공한다.

• Journal of Electrical Engineering and Technology
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• 제8권5호
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• pp.1221-1226
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• 2013

In this paper, the equivalent circuit for the efficiency calculation by precise estimation of the linkage flux, inductance and iron loss resistance was calculated accurately. In addition, the driving characteristics according to the current phase angle are analyzed and the maximum efficiency point is calculated. And then, analyzed and experimental values of the efficiency were compared. So, causes of error were expected to be vibration and noise by harmonic distortion of the voltage and current, and mechanical loss of dynamometer. In addition, the driving characteristics according to the current phase angle are analyzed and the maximum efficiency point is calculated.

• 한국공작기계학회논문집
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• 제15권3호
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• pp.97-103
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• 2006

The development of a heat exchanger production model based on the microlamination technology and it's economic efficiency is addressed. A microchannel production model is proposed for the high-volume production. The microlamination system is made up of lamina patterning, laminae sorting and laminae bonding. A cost estimation model is developed based on the hewn cycle time and capital equipment costs. An economic efficiency analysis is performed to determine the cost drivers under the different market and product scenarios. The result of the economic efficiency analysis indicated that the device size and the production rate have a great effect on the overall manufacturing cost of microlamination devices. And it can be concluded that the microlamination should focus on bonding larger laminae and reducing both cycle time and warpage.

• 방송공학회논문지
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• 제18권4호
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• pp.647-650
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• 2013

HEVC RExt(High Efficiency Video Coding Range Extension)는 RGB/YUV 4:2:2 4:4:4 색 샘플링 영상과 10비트 심도 이상의 영상 지원을 목표로 한다. RGB 영상은 YUV 4:2:0 색 샘플링 영상과는 달리 색평면 간 높은 상관도를 갖고 있으며, 이를 이용하여 화소값을 예측하는 기법들이 JCT-VC 표준화 회의에서 기고되었다. 하지만 일반적으로 RGB 영상의 고주파수 성분은 색평면 간 낮은 상관도를 갖고 있으며, 이는 색평면 간 예측 시 부호화 효율 저하의 원인이 된다. 따라서 본 논문에서는 색평면 간 예측 시 고주파수 성분을 저역통과필터를 통해 적응적으로 제거하는 기법을 제안한다. HEVC RExt의 RGB 영상을 통한 실험 결과, 본 논문에서 제안하는 기법은 기존 색평면 간 예측 기법에 비해 큰 복잡도의 증가 없이 평균 0.6%의 BD(Bjontegaard Distortion)-율 이득을 얻을 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.32-35
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• 2004

In boundary estimation in Electrical Impedance Tomography (EIT), conventional method is the modified Newton Raphson (mNR) method .The mNR is famous for good method since has good convergence and robustness against noisy data. But the mNR is low efficiency to get and update Jacobian matrix. So, the mNR become very slow algorithm. We propose the Quasi Newton (QN) method to improve efficiency which will lead to speed up in boundary estimation. The QN can improve a low efficiency by using estimated Jacobian matrix contrary to using exactly calculated Jacobian matrix, this used by the mNR. And finally, we propose the modified Quasi Newton (mQN) method because the QN has some problems such as bad early convergence rate and instability of 'divided by zero'. For the verification of the propose method, numerical experiments are conducted and the results show a good performance.

• Communications for Statistical Applications and Methods
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• 제10권2호
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• pp.607-617
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• 2003

This paper offers a practical comparison of efficiency between local likelihood approach and conventional kernel approach in density estimation. The local likelihood estimation procedure maximizes a kernel smoothed log-likelihood function with respect to a polynomial approximation of the log likelihood function. We use two types of data driven bandwidths for each method and compare the mean integrated squares for several densities. Numerical results reveal that local log-linear approach with simple plug-in bandwidth shows better performance comparing to the standard kernel approach in heavy tailed distribution. For normal mixture density cases, standard kernel estimator with the bandwidth in Sheather and Jones(1991) dominates the others in moderately large sample size.

• 조명전기설비학회논문지
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• 제21권4호
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• pp.96-103
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• 2007

In this paper, we present a novel and numerically efficient algorithm for high resolution TOA(Time Of Arrival) estimation under indoor radio propagation channels. The proposed algorithm is not dependent on the structure of receivers, i.e, it can be used with either coherent or non-coherent receivers. The TOA estimation algorithm is based on a high resolution frequency estimation algorithm of Minimum-norm. The efficiency of the proposed algorithm relies on numerical analysis techniques in computing signal or noise subspaces. The algorithm is based on the two step procedures, one for transforming input data to frequency domain data and the other for estimating the unknown TOA using the proposed efficient algorithm. The efficiency in number of operations over other algorithms is presented. The performance of the proposed algorithm is investigated by means of computer simulations.. Throughout the analytic and computer simulation results, we show that the proposed algorithm exhibits superior performance in estimating TOA estimation with limited computational cost.

• 한국산업융합학회 논문집
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• 제25권4_2호
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• pp.707-714
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• 2022

Versatile Video Coding (VVC) is the most recent video coding standard, which had been developed by Joint Video Expert Team (JVET). It can improve significant coding performance compared to the previous standard, namely High Efficiency Video Coding (HEVC). Although VVC can achieve the powerful coding performance, it requires the tremendous computational complexity of VVC encoder. Especially, affine motion compensation (AMC) was adopted the block-based 4-parameter or 6-parameter affine prediction to overcome the limit of translational motion model while VVC require the cost of higher encoding complexity. In this paper, we proposed the early termination of AMC that determines whether the affine motion estimation for AMC is performed or not. Experimental results showed that the proposed method reduced the encoding complexity of affine motion estimation (AME) up to 16% compared to the VVC Test Model 17 (VTM17).

• International Journal of Control, Automation, and Systems
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• 제6권3호
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• pp.320-326
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• 2008

This paper studies the problem of fault estimation using adaptive fault diagnosis observer. A fast adaptive fault estimation (FAFE) approximator is proposed to improve the rapidity of fault estimation. Then based on linear matrix inequality (LMI) technique, a feasible algorithm is explored to solve the designed parameters. Furthermore, an extension to sensor fault case is investigated. Finally, simulation results are presented to illustrate the efficiency of the proposed FAFE methodology.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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• pp.287-290
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• 2002

The block matching algorithm motion estimation is a soft-core for hardwired motion estimation block in MPEG-2, H.261 encoder. This motion estimation has been tested and verified to be valid for implementation of FPGA. Efficiency performance of the synthesized motion estimation was up to 89%, and the average PSNR between the original image and the motion-compensated image is 38dB.