• Journal of KIISE:Computer Systems and Theory
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• v.26 no.6
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• pp.627-635
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• 1999

물체의 3차원 모델을 음영처리하기 위해서는 물체 표면의 각 점에서 법선 벡터를 계산해야 한다. 복섹 기반의 볼륨 데이터는 표면에 대한 기하학적 정보가 없기 때문에 이웃 점들의 상대적인 위치나 데이터 값의 차이로부터 법선 벡터를 추정할 수 밖에 없다. 기존에 고안된 법선 벡터추정 연산자는크기가 고정되어 있기 때문에 제한된 영역에서만 법선 벡터를 정확하게 계산하고 나머지 영역에서는 오류를 유발한다. 이 논문에서는 표면을 구성하는 점들의 공간적 배치나 그 점들의 데이터값에 따라 크기가 변하는 가변 중심 편차 연산자와 이를 이용한 법선 벡터 추정 방법을 제안한다. 이 연산자를 사용하면 기존연산자들보다 정확하게 법선 벡터를 추정할 수 있으며, 동일한 화질인 경우 계산 시간이 상당히 단축된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.562-567
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• 2000

This paper proposed a speed estimator using MRAC(Model Reference Adaptive Control) for sensorless vector control. It is robust for parameter variation and the estimated speed is used as feedback in a vector control system. Computer simulation is presented to confirm the theoretical analysis.

• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.479-485
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• 2002

We propose a vector analysis for designing multimode-interference power splitters, which can show an arbitrary splitting ratio. Power splitting is a fundamental characteristic in integrated optical circuits and its value would be multiplied for many applications if the splitting ratio could be selected freely. Since the vector analysis utilizes a graphical method based on the previously-reported mathematical results of multimode interference, it shows an excellent advantage especially for designing power splitters with an arbitrary splitting ratio.

• The KIPS Transactions:PartA
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• v.12A no.3 s.93
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• pp.263-272
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• 2005

The addressing mode for data is performed by the software in yon Neumann-concept(SISD) computer a priori without hardware design of an address counter for operands. Therefore, in the addressing mode for the vector the corresponding variables as much as the number of the elements should be specified and used also in the software method. This is because not for operand but only for an instructions, quasi PC(program counter) is designed in hardware physically. A vector has a characteristic of a structural dimension. In this paper we propose to design a hardware unit physically external to the CPU for addressing only the elements of a vector unit with the structure and dimension. Because of the high speed performance for a vector processing it should be designed in the SIMD pipeline mechanics. The proposed mechanics is evaluated through a simulation. Our result shows $12\%$ to $30\%$ performance enhancement over CRAY architecture under the same hardware consideration(processing unit).

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.185-192
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• 2004

This paper presents face recognition using vector quantization in the eigenspace of the faces. The existing eigenface method is not enough for representing the variations of faces. For making up for its defects, the proposed method use a clustering of feature vectors by vector quantization in eigenspace of the faces. In the trainning stage, the face images are transformed the points in the eigenspace by eigeface(eigenvetor) and we represent a set of points for each people as the centroids of vector quantizer. In the recognition stage, the vector quantizer finds the centroid having the minimum quantization error between feature vector of input image and centriods of database. The experiments are performed by 600 faces in Faces94 database. The existing eigenface method has minimum 64 miss-recognition and the proposed method has minimum 20 miss-recognition when we use 4 codevectors. In conclusion, the proposed method is a effective method that improves recognition rate through overcoming the variation of faces.

• Journal of IKEEE
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• v.12 no.2
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• pp.124-130
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• 2008

Vector Graphics describes an image with mathematical statements instead of pixel information. Which enables easy scalability without loss in image quality and usually results in a much smaller file size compared with bitmap images. In this paper, we propose Vector Graphics Accelerator for mobile device with scan-line edge flag algorithm to render vector image without sorting process of edge. Proposed Vector Graphics Accelerator was verified with OpenVG 2D Vector image. The estimated processing time of proposed Accelerator with Tiger image is 12ms on Tessellation process, and total rendering time is 208ms. Estimated rendering performance with Tiger image is about 5 frame per second

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.1 no.2
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• pp.19-29
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• 2002

This paper deals with heterogeneous video transcoding, which is one of key technologies for the MPEG-21 digital item adaptation. It is noted that motion vector reuse Is necessarily required for computationally efficient implementation of the transcoder. But conventional transcoder employs the motion vector reuse methods only for P-pictures. In this paper, we propose two new motion vector reuse method for B-pictures. By using the proposed methods, we can produce the MPEG bitstream, which is encoded in a I/B/P picture mode. Computer simulation results show that the proposed methods can reduce the computational burden of the transcoder significantly, while allowing only a small amount of performance degradation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.6
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• pp.1-9
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• 2010

In this paper, we propose a hi-speed/low-power Extended QRD-RLS(QR-Decomposition Recursive Least Squares) equalizer with systolic array structure. In the conventional systolic array structure, vector mode CORDIC on the boundary cell calculates angle of input vector, and the rotation mode CORDIC on the internal cell rotates vector. But, in the proposed structure, it is shown that implementation complexity can be reduced using the rotation direction of vector mode CORDIC and rotation mode CORDIC. Furthermore, calculation time can be reduced by 1/2 since vector mode and rotation mode CORDIC operate at the same time. Through HDL coding and chip implementation, it is shown that implementation area is reduced by 23.8% compared with one of conventional structure.

• The Journal of the Acoustical Society of Korea
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• v.22 no.4
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• pp.308-314
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• 2003

Wideband speech communications with 7㎑ bandwidth can provide high-quality speech services that are almost impossible with current narrow-band speech communications with 3.4 ㎑ bandwidth, and AMR wideband codec was recently developed for these services. The performance of AMR wideband codec is excellent due to its wideband information and partially to ACELP structure, but it requires high computational complexity especially in codebook search. In this paper, to solve this problem, an efficient codebook search method for AMR wideband codec is proposed. The proposed method first determines the coarse initial codevector, then improves the performance of codevector by replacing a poor pulse in codevector with better one iteratively. Simulations show that AMR wideband codec with proposed codebook search method has higher performance with much less computational cost than conventional AMR wideband codec.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9C
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• pp.1330-1336
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• 2004

This paper addresses an adaptive motion vector prediction algorithm to improve the performance of video encoder. The block-based motion vector is characterized by non-stationary local statistics so that the coefficients of LS (Least Squares) based linear motion can be optimized. However, it requires very expensive computational cost. The proposed algorithm using LS approach with spatially varying motion-directed property adaptively controls the coefficients of the motion predictor and reduces the computational cost as well as the motion prediction error. Experimental results show the capability of the proposed algorithm.