• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.12
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• pp.66-74
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• 2001

In this paper, we proposed the new structure of the Rake Finger using Walsh Switch, the shared accumulator, and the pipeline FWHT(Fast Walsh Hadamard Transform) algorithm for reducing the signal processing complexity resulting from the increase of the number of data correlators. The function simulation of the proposed architecture is performed by Synopsys tool and the timing simulation is performed by Compass tool. The number of computational operation in the proposed data correlators is 160 additions and the conventional ones is 512 additions when the number of walsh code channels is 4. As a result, it is reduced about 3.2 times other than the number of computational operation of the conventional ones. Also, the result shows that the data processing time of the proposed Rake Finger architecture is 90,496[ns] and the conventional ones is 110,696[ns]. It is 18.3% faster than the data processing time of the conventional Rake Finger architecture.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.4
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• pp.106-114
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• 2016

In this paper, we propose an efficient integer inverse transform structure for vp9 decoder. The proposed structure is a hardware structure which is easy to control and requires less hardware resources, and shares algorithms for realizing entire DCT(Discrete Cosine Transform), ADST(Asymmetric Discrete Sine Transform) and WHT(Walsh-Hadamard Transform) in vp9. The integer inverse transform for vp9 google model has a fast structure, named butterfly structure. The integer inverse transform for google C model, unlike universal fast structure, takes a constant rounding shift operator on each stage and includes an asymmetrical sine transform structure. Thus, the proposed structure approximates matrix coefficient values for all transform mode and is used to matrix operation method. With the proposed structure, shared operations for all inverse transform algorithm modes can be possible with reduced number of multipliers compared to the butterfly structure, which in turn manages the hardware resources more efficiently.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.4
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• pp.53-60
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• 2007

In a known plaintext scenario, fast correlation attack is very powerful attack on stream ciphers. Most of fast correlation attacks consider the cryptographic problem as the suitable decoding problem. In this paper, we introduce advanced multi-pass fast correlation attack which is based on the fast correlation attack, which uses parity check equation and Fast Walsh Transform, proposed by Chose et al. and the Multi-pass fast correlation attack proposed by Zhang et al. We guess some bits of initial states of the target LFSR with the same method as previously proposed methods, but we can get one more bits at each passes and we will recover the initial states more efficiently.

• Journal of Biomedical Engineering Research
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• v.7 no.1
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• pp.67-74
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• 1986

We have implemented data compression and reconstruction by using a fast Walsh transform. The ECG signals were generated by an ECG BimLllator (KONT- RON). The sampling frequency was 480 Hz and the data point number used was 512. In order to eliminate the 60 Hz noise and baseline drift, a digital notch filter was designed. We obtaine!1 a compression ratio of 5 : 1 and at this ratio it was possible to obtain a true diagnosis and an ECG morphology analysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.6
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• pp.73-81
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• 2001

This study uses the distributed parameter systems resented by the spatial discretization technique. In this paper, the distributed parameter systems are converted into lumped parameter systems, End fast Walsh transform and the Picard's iteration method are allied to analysis the state of the systems. This thesis presents a new algorithm which usefully exercises the optimal contro1 in the distributed parameter systems. In exercising the optimal control of the distributed parameter systems, the excellent consequences are found without using the existing decentralized contro1 or hierarchical control method. This study can be applied to the linear time-varying systems and the non-linear systems. Farther researches are required to solve the problems of convergence in case of the numerous applicable intervals. The simulation proves the effectiveness of the proposed algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2A
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• pp.116-123
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• 2002

The jacket matrix is based on the Walsh-Hadamard matrix and an extension of it. While elements of the Walsh-Hadamard matrix are +1, or -1, those of the Jacket matrix are ${\pm}$1 and ${\pm}$$\omega$, which is $\omega$, which is ${\pm}$j and ${\pm}$2$\sub$n/. This matrix has weights in the center part of the matrix and its size is 1/4 of Hadamard matrix, and it has also two parts, sigh and weight. In this paper, instead of the conventional Jacket matrix where the weight is imposed by force, a simple Jacket sequence generation method is proposed. The Jacket sequence is generated by AND and Exclusive-OR operations between the binary indices bits of row and those of column. The weight is imposed on the element by when the product of each Exclusive-OR operations of significant upper two binary index bits of a row and column is 1. Each part of the Jacket matrix can be represented by jacket sequence using row and column binary index bits. Using Distributed Arithmetic (DA), we present a VLSI architecture of the Fast Jacket transform is presented. The Jacket matrix is able to be applied to cryptography, the information theory and complex spreading jacket QPSK modulation for WCDMA.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.26-29
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• 2012

In this paper, we propose a Single Carrier Frequency Division Multiple Access(SC-FDMA) scheme with greatly enhanced tolerance of timing offset among the users. The type of the proposed scheme is similar to code spread Multiple Carrier Direct Spread Code Division Multiple Access(MC DS CDMA). The proposed scheme performs partial Discrete Fourier Transform(DFT) in order to solve high Peak to Average Power Ratio(PAPR) of the MC DS CDMA before Inverse Fast Fourier Transform(IFFT). Exploiting the property Properly Scrambled Walsh-Hadamard(PSW) code has zero correlation despite ${\pm}1$ chip timing offset, the proposed scheme achieves Multiple Access Interference free performance with the timing offset up to ${\pm}1$ OFDM symbol duration with low PAPR. In contrast, the other existing schemes in comparison undergo severe performance degradation even with small timing offset in multipath fading channel.

• Journal of Biomedical Engineering Research
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• v.11 no.1
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• pp.163-170
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• 1990

In this paper, fast Fourier transform and fast Walsh transform algorithm are studied for ECG data compression. ECG data-12 bit samples digitized at 480 samples-are segmented into QRS complexes and 50 intervals by di%ital derivative filter, which used for detection of QS width and difrerenre compressed in Fourler or welsh domain. And also the existing techniques for data compression-TP, MTP, CORTES, AZTEC, MCORTES, which have not been evaluated with a common measurement of goodness, were processed to get absolute terms of values in the same condition.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.2
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• pp.32-38
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• 2000

One of the most popular algorithm in adaptive signal processing is the least mean square(LMS) algorithm. The majority of these papers examine the LMS algorithm with a constant step size. The choice of the step size reflects a tradeoff between misadjustment and the speed of adaptation. Subsequent works have discussed the issue of optimization of the step size or methods of varying the step size to improve performance. However there is as yet no detailed analysis of a variable step size algorithm that is capable of giving both the adaptation speed and the convergence. In this paper we propose a new variable step size algorithm where the step size adjustment is controlled by the gradient of error square. The proposed algorithm is performed in the Walsh-Hadamard domain in real-valued orthogonal transform because of fast convergence. The simulation results using the new algorithm for noise canceller system is described. They are compared to the results obtained by other algorithms. It is shown that the proposed algorithm produces good results compared with conventional algorithms.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2084-2086
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• 2001

This study uses distributed parameter systems as the spatial discretization technique, modelling in lumped parameter systems, and applies orthogonal transform and the Picard's iteration method to high order partial differential equations and matrix partial differential equations. In exercising optimal control of distributed parameter systems, excellent consequences are found without using the existing decentralized control or hierarchical control method.