• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1276-1286
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• 2002

The numerical techniques are presented to solve the static and dynamic contact problems of deformable bodies having large rotations of the contact surfaces. The contact conditions on the possible contact surfaces are enforced by using the contact error vector, and an iterative scheme similar to augmented Lagrange multiplier method is employed to reduce the contact error vector monotonically. For dynamic contact problems using implicit time integration, a contact error vector is also defined by combining the displacement, velocity, and acceleration on the contact surface. The suggested iterative technique is implemented to ABAQUS by using the UEL subroutine UEL. In this work, after the computing procedures to solve the frictional contact problems are explained, the numerical examples are presented to compare the present solutions with those obtained by ABAQUS.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.51-56
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• 1998

This paper presents modal contribution method to reduce vehicle vibration. Normal mode analysis is performed to obtain modal vector matrix. The proposed method uses this modal vector matrix to evaluate forced response of an active mode to the applied engine forces and the rotating force due to wheel unbalance mass. Comparing the responses, of the specific active mode with one another, it can be easily done to determine most contributed mode in the interesting frequency band. Then we can find dominant bushes by the strain energy distribution of the mode. Vibration response is decrease with modification of those bushes.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.877-878
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• 2008

We suggest a feature reduction method to classify mouse function data sets, which integrate several biological data sets represented as high dimensional vectors. To increase classification accuracy and decrease computational overhead, it is important to reduce the dimension of features. To do this, we employed Hybrid Huberized Support Vector Machine with kernels used for a kernel logistic regression method. When compared to support vector machine, this a pproach shows the better accuracy with useful features for each mouse function.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.557-560
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• 2003

Voice is one of the promising biometrics because it is one of the most convenient ways human would distinguish someone from others. The target of speaker verification is to divide the client from imposters. Support Vector Machine(SVM) is in the limelight as a binary classifier, so it can work well in speaker verification. In this paper, we combined SVM with genetic algorithm(GA) to reduce the dimensionality of input feature. Experiments were conducted with Korean connected digit database using different feature dimensions. The verification accuracy of SVM with GA is slightly lower than that of SVM, but the proposed algorithm has greater strength in the memory limited systems.

• 대한전자공학회논문지
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• 제26권8호
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• pp.1227-1237
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• 1989

In this paper, we propose a lossless progressive image transmission scheme using hierarchical pyramid structure and classified vector quantizer in DCT domain. By adopting DCT to the hierarchical pyramid signals, we can reduce the spatial redundance. Moreover, the DCT coefficients can be encoded efficiently by using classified vector quantizer in DCT domain. The classifier is simply based on the variance of a subblock. Also, the mirror set of training set of images can improve the robustness of codebooks. Progressive image transmission can be achieved through following processes: from top to bottom level of planes in a pyramid, and from high to low AC variance class in a plane. Some simulation results with real images show that the proposed coding scheme yields a good performance at below 0.3 bpp and an excellent result at 0.409 bpp. The proposed coding scheme is well suited for lossless progressive image transmission as well as image data compression.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.46-53
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• 2006

This paper presents the fault diagnosis of induction motor based on support vector machine (SVMs). SVMs are well known as intelligent classifier with strong generalization ability. Application SVMs using kernel function is widely used for multi-class classification procedure. In this paper, the algorithm of SVMs will be combined with feature extraction and reduction using component analysis such as independent component analysis, principal component analysis and their kernel (KICA and KPCA). According to the result, component analysis is very useful to extract the useful features and to reduce the dimensionality of features so that the classification procedure in SVM can perform well. Moreover, this method is used to induction motor for faults detection based on vibration and current signals. The results show that this method can well classify and separate each condition of faults in induction motor based on experimental work.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권4호
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• pp.229-234
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• 2007

In this paper, we present an efficient instruction set architecture using vector register file hardware to accelerate operation of general matrix-vector operations in DSP microprocessor. The technique enables in-situ row-access as well as column access to the register files. It can reduce the number of memory access significantly. The technique is especially useful for block-based video signal processing kernels such as FFT/IFFT, DCT/IDCT, and two-dimensional filtering. We have applied the new instruction set architecture to in-loop deblocking filter processing in H.264 decoder. Performance comparisons show that the required load/store operations for the in-loop deblocking filter can be reduced about 42%. The architecture would improve the processing speed, and code density in DSP microprocessor especially for video signal processing substantially.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.435-440
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• 2009

The scalable vector graphics (SVG) standard has allowed the complex bitmap images to be represented by vector based graphics and provided some advantages over the raster based graphics in applications, for example, where scalability is required. This paper presents an algorithmto convert bitmap images into SVG format. The algorithm is an integration of pixel-level triangulation, data dependent triangulation, a new image mesh simplification algorithm, and a polygonization process. Both triangulation techniques enable the image quality (especially the edge features) to be preserved well in the reconstructed image and the simplification and polygonization procedures reduce the size of the SVG file. Experiments confirm the effectiveness of the proposed algorithm.

• Journal of Power Electronics
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• 제13권4호
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• pp.647-655
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• 2013

In this paper, an approach to reduce the common-mode voltage and to eliminate narrow pulse for implemented AC-DC matrix converters is presented. An improved space vector modulation (SVM) strategy is developed by replacing the zero space vectors with suitable pairs of active ones. Further, while considering the commutation time, the probability of narrow pulse in the conventional and proposed SVM methods are derived and compared. The advantages of the proposed scheme include: a 50% reduction in the peak value of the common-mode voltage; improved input and output performances; a reduction in the switching loss by a reduced number of switching commutations and a simplified implementation via software. Experimental results are presented to demonstrate the correctness of the theoretical analysis, as well as the feasibility of the proposed strategy.

• 대한전자공학회논문지
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• 제25권2호
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• pp.211-219
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• 1988

In this paper effective block matching algorithms are proposed to find the motion vector. There are two approaches to the estimation of the motion vector in MCC (motion compensated coding), i.e.pel(pixel element) recursive algorithm and block matching algorithm. The search algorithm in this paper is based on the block matching method. The advantage of this algorithm is the reduction of the computation time. In order to reduce the computation time, three mathods are proposed in this paper. These new algorithms are faster than other methods. Compared with the three step algorithm by Koga et al., the average ratio of the computational savings obtained from the proposed algorithm is about 3-4.