• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1069-1074
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• 2008

This paper presents an efficient architecture for $2^n$-point DCT algorithm. The proposed approach makes use of the fact that, in most DCT applications, the scaling operation in the DCT unit can be eliminated and combined with the scaling operation in the quantizer unit. This important property is efficiently exploited with the CORDIC(COordinate Rotation DIgital Computer) algorithm to produce a regular architecture suitable for VLSI implementation. Although there have been several attempts to exploit CORDIC algorithm in developing DCT architectures, the proposed approach provides the most efficient way for scaled DCT applications by completely eliminating the scale factor compensation.

• Tunnel and Underground Space
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• v.30 no.1
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• pp.87-97
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• 2020

Fracture toughness of rock is a constant that can indicate the initiation and propagation of cracks due to blasting, excavation, etc. Scaled model tests have been applied to the behavior of tunnels and the stability of limestone mines. Through the scaled model, damaged zone evaluation due to blasting is also carried out, and the scale factor is not applied to the failure-related factors. In this study, DCT (diametral compression test) and finite element method ATENA2D numerical analysis results were compared to determine whether the scale factor could be applied to the fracture toughness of rock. The theoretical values of the scale factor applied to the fracture toughness of the rock and the DCT test results and the numerical results are 0.21~0.46, 0.40, and 0.99MPa ${\sqrt{m}}$ respectively, so these three values should be considered when determining scale factor. It is necessary to derive a suitable scale factor in consideration of the length, time, and mass to which the scale factor is applied, as well as the values of the scale factor of major design factors such as uniaxial compressive strength and density.

• Journal of Software Assessment and Valuation
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• v.17 no.2
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• pp.161-172
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• 2021

Neuromorphic architecture is drawing attention as a next-generation computing that supports artificial intelligence technology with low energy. However, FPGA embedded boards based on Neuromorphic architecturehave limited resources due to size and power. In this paper, we compared and evaluated the image reduction method using the interpolation method that rescales the size without considering the feature points and the DCT (Discrete Cosine Transform) method that preserves the feature points as much as possible based on energy. The scaled images were compared and analyzed for accuracy through CNN (Convolutional Neural Networks) in a PC environment and in the Nengo framework of an FPGA embedded board.. As a result of the experiment, DCT based classification showed about 1.9% higher performance than that of interpolation representation in both CNN and FPGA nengo environments. Based on the experimental results, when the DCT method is used in a limited resource environment such as an embedded board, a lot of resources are allocated to the expression of neurons used for classification, and the recognition rate is expected to increase.

• Nuclear Engineering and Technology
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• v.43 no.4
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• pp.343-354
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• 2011

It is critically important to identify unexpected loose parts in a nuclear reactor pressure vessel, since they may collide with and cause damage to internal structures. Mass estimation can provide key information regarding the kind as well as the location of loose parts. This study proposes a mass estimation method based on an artificial neural network (ANN), which can overcome several unresolved issues involved in other conventional methods. In the ANN model, input parameters are the discrete cosine transform (DCT) coefficients of the auto-power spectrum density (APSD) of the measured impact acceleration signal. The performance of the proposed method is then evaluated through application to a large-sized plate and a 1/8-scaled mockup of a reactor pressure vessel. The results are compared with those obtained using a conventional method, the frequency ratio (FR) method. It is shown that the proposed method is capable of estimating the impact mass with 30% lower relative error than the FR method, thus improving the estimation performance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.72-78
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• 2008

Although the H.264 video coding scheme is popular, it is not efficient for high-definition (HD) video coding because the size of its macroblock is relatively small for the HD video resolution. In this paper, we propose a new intra coding scheme based on the enlarged macroblock size. For the luminance component, intra $4{\times}4$ prediction and intra $16{\times}16$ prediction in H.264 are scaled into intra $8{\times}8$ prediction and intra $32{\times}32$ prediction, respectively. For the chrominance components, intra $8{\times}8$ prediction is extended to intra $16{\times}16$ prediction. Along with the $8{\times}8$ basic coding block size, an $8{\times}8$ integer discrete cosine transform (DCT) is used. Experimental results show that the proposed algorithm improves coding efficiency of the intra coding for HD video: PSNR gain by 0.23dB and bit-rate reduction by 5.32% on average.