• Journal of Information Processing Systems
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• 제11권3호
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• pp.354-369
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• 2015

Recently, there has been an increasing demand of high data rates services, where several multiuser multiple-input multiple-output (MU-MIMO) techniques were introduced to meet these demands. Among these techniques, vector perturbation combined with linear precoding techniques, such as zero-forcing and minimum mean-square error, have been proven to be efficient in reducing the transmit power and hence, perform close to the optimum algorithm. In this paper, we review several fixed-complexity vector perturbation techniques and investigate their performance under both perfect and imperfect channel knowledge at the transmitter. Also, we investigate the combination of block diagonalization with vector perturbation outline its merits.

• 한국정보통신학회논문지
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• 제15권2호
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• pp.455-461
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• 2011

블록정합 기법을 이용한 객체추적에서 크기가 다양하고 수시로 변하는 객체를 추적하기 위해 고정 정합블록을 사용하는 것은 적합하지 못하다. 본 논문은 동적 환경을 위한 적응적 정합블록을 정의하고, 이를 위한 블록정합 알 고리즘을 제안한다. 정합블록은 $42{\times}42$ 화소의 넓은 영역에 $10{\times}10$ 화소의 주 블록과 $6{\times}6$ 화소의 부 블록 8개로 구성되고, 영역 중심에 위치한 주 블록은 객체 블록으로 사용되고, 영역의 외곽에 위치한 부 블록은 객체블록을 위한 후보 블록으로 사용된다. 제안된 알고리즘은 부 블록에서 이전 10 프레임의 움직임 벡터를 이용해 객체블록을 추출하고, 주 블록과 추출된 객체블록을 이용해 블록정합을 수행한다. 성능 평가를 위한 실험들은 제안된 알고리즘이 정합블록에서 유효한 객체블록만을 적절히 추출하고, 자유로운 움직임을 갖는 객체를 영상의 중심 영역에 유지시켜 주는 것을 보여주고 있다.

• Journal of Electrical Engineering and Technology
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• 제11권2호
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• pp.519-528
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• 2016

In order to achieve fast computational speed with good visual quality of output video, we propose a frequency domain based new fractal video compression scheme. Normalized cross correlation is used to find the structural self similar domain block for the input range block. To increase the searching speed, cross correlation is implemented in the frequency domain using FFT with one computational operation for all the domain blocks instead of individual block wise calculations. The encoding time is further minimized by applying rotation and reflection DFT properties to the IFFT of zero padded range blocks. The energy of overlap small size domain blocks is pre-computed for the entire reference frame and retaining the energies of the overlapped search window portion of previous adjacent block. Quadtree decompositions are obtained by using domain block motion compensated prediction error as a threshold to control the further partitions of the block. It provides a better level of adaption to the scene contents than fixed block size approach. The result shows that, on average, the proposed method can raise the encoding speed by 48.8 % and 90 % higher than NHEXS and CPM/NCIM algorithms respectively. The compression ratio and PSNR of the proposed method is increased by 15.41 and 0.89 dB higher than that of NHEXS on average. For low bit rate videos, the proposed algorithm achieve the high compression ratio above 120 with more than 31 dB PSNR.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.99-107
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• 2004

Lubrication characteristics between a cylinder block and a valve plate for high speed bent-axis type hydraulic pump play an important role in volumetric efficiency and durability of pump. In this paper, a finite element method is presented for the computation of the pressure distribution between a cylinder block and a valve plate for high speed bent-axis type hydraulic pump. Also, a Runge-Kutta method is applied to simulate the cylinder block dynamics of three-degrees of freedom motion. From the results of computation, we can draw two major conclusions. One is related to the fluid film characteristics between a cylinder block and a valve plate and the other is related to the average leakage that is determined by the pressure gradient and the clearance near the discharge port. The numerical results of cylinder block dynamics were compared with the experimental results using eddy-current type gap sensors those are fixed at a pump housing.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제15권4호
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• pp.300-304
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• 2015

A low bit rate speech coder based on the non-uniform sampling technique is proposed. The non-uniform sampling technique is based on the detection of inflection points (IP). A speech block is processed by the IP detector, and the detected IP pattern is compared with entries of the IP database. The address of the closest member of the database is transmitted with the energy of the speech block. In the receiver, the decoder reconstructs the speech block using the received address and the energy information of the block. As results, the coder shows fixed data rate contrary to the existing speech coders based on the non-uniform sampling. Through computer simulation, the usefulness of the proposed technique is shown. The SNR performance of the proposed method is approximately 5.27 dB with the data rate of 1.5 kbps.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.9-11
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• 2005

We propose a new content-based image retrieval using a block color co-occurrence matrix (BCCM) and pattern correlogram. In the proposed method, the color feature vectors are extracted by using BCCM that represents the probability of the co-occurrence of two mean colors within blocks. Also the pattern feature vectors are extracted by using pattern correlogram which is combined with spatial correlation of pattern. In the proposed pattern correlogram method. after block-divided image is classified into 48 patterns with respect to the change of the RGB color of the image, joint probability between the same pattern from the surrounding blocks existing at the fixed distance and the center pattern is calculated. Experimental results show that the proposed method can outperform the conventional methods as regards the precision and the size of the feature vector dimension.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 춘계 종합학술대회 논문집
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• pp.470-474
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• 2005

GOP구조를 제어하여 양질의 영상을 제공하기 위한 방법들이 많이 제안되어 있다. 그러나 기존의 알고리즘들은 GOP 구조를 결정하기 위해 일정량의 영상을 사전 검토하여야 하는 과정을 거쳐야 하므로 계산 량이 증가하게 되어 대용량 프레임 메모리가 필요하고 시간적으로도 지연되므로 실시간 적응에는 적합하지 못하다. 본 논문에서는 매크로 블록을 기반으로 한 실시간 적응적인 알고리즘을 제안한다. 제안한 매크로 블록 기반의 GOP 구조을 이용하여 효과적인 영상처리 결과를 얻었다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.71-75
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• 2009

In this paper, we present a real-time method to detect moving objects in a rotating and zooming camera. It is useful for camera surveillance of fixed but rotating camera, camera on moving car, and so on. We first compensate the global motion, and then exploit the displaced frame difference (DFD) to find the block-wise boundary. For robust detection, we propose a kind of image to combine the detections from consecutive frames. We use the block-wise detection to achieve the real-time speed, except the pixel-wise DFD. In addition, a fast block-matching algorithm is proposed to obtain local motions and then global affine motion. In the experimental results, we demonstrate that our proposed algorithm can handle the real-time detection of common object, small object, multiple objects, the objects in low-contrast environment, and the object in zooming camera.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.843-846
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• 2000

An optical flow-based motion estimation algorithm is proposed for video coding. The algorithm uses block-matching motion estimation with an adaptive search region. The search region is computed from motion fields that are estimated based on the optical flow. The algorithm is based on the fact that true block-motion vectors have similar characteristics to optical flow vectors. Thereafter, the search region is computed using these optical flow vectors that include spatial relationships. In conventional block matching, the search region is fixed. In contrast, in the new method, the appropriate size and location of the search region are both decided by the proposed algorithm. The results obtained using test images show that the proposed algorithm can produce a significant improvement compared with previous block-matching algorithms.

• 대한안전경영과학회지
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• 제18권4호
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• pp.91-97
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• 2016

Hospital costing has generally been using ABC costing method. However, based on increase of expensive equipment, the fixed cost is increased in the hospital industry. The most common equipment industry are using building block costing method for depreciation and equipment management costing elements. Additionally it presents three options that may be considered to be supported by the IT system to find the most appropriate alternative.