• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.211-214
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• 1998

TCM(Trellis-Coded Modulation)은 대역폭과 전력이 제한된 채널환경에서 채널부호화 기술과 변조기술을 결합시켜 대역폭의 증가없이 에러정정능력을 개선시키는 통신 기술이다. 본 논문에서는 TCM 신호의 복호시 사용되는 Viterbi decoder에서 traceback depth의 감소에 따른 BER(Bit Error Rate)의 증가를 개선하기 위해 수신부에서 설정하는 traceback depth를 주기로 blocking하여 TCM encoder의 입력시퀀스에 zero padding bits를 추가시키는 새로운 알고리듬을 제안한다. 모의실험결과, traceback depth가 50인 hard decision의 경우 약 2~2.5dB, 4-level soft decision과 8-level soft decision의 경우 약 0.3~2dB의 coding gain을 얻을 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.9-15
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• 1990

A soft-decision decoding algorithm for linear binary block codes is proposed, for minimizing the block error probability. To compare the proposed algorithm with already established decoding methods, computer simulations are performed for the (7,4)Hamming code and the (23,12) Golay code. The average number of hard-decision decoding is always less then 2, and approaches to 1 when the signal to noise ratio is sufficiently large. These results show that the proposed algorithm reduces the decoding complexity.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.753-760
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• 2003

An existing studies concern about movement of pile bridge abutments. However, lateral displacement cause the serious failure of bridge by embankment under soft soil lateral flow A intention is obtained by analyzing the relationship between the safety factor of evaluation for lateral movements. Precise investigation and analysis are performed, in which the lateral movement of bridge abutments has occurred, and construct design strut-slab between bridge abutments in order to restraint lateral flow. As a result of this study, it was found that when evaluation for lateral movements is allowed to use Tschebotarioff's method and lateral flow decision number (I) and revision lateral flow decision number (M$_{I}$) by Korea Highway Corporation. Most important thing is decision of pressure of lateral flow at this case. Tschebotarioff's isoscales triangle method have no trouble analysis of pressure of lateral flow. Strut-slab method are nearly not have constructed case in this field site study that applied method. The method are between abutments combined steel strut and reinforced concrete slab. This method are effective restraint lateral flow but have little difficulty if long span bridge between abutments.s.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.9
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• pp.738-745
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• 2012

This paper proposes an approximated soft decision demapping algorithm with low computational complexity for coded 4+12+16 amplitude phase shift keying (APSK) in an additive white Gaussian noise (AWGN) channel. To derive the proposed algorithm, we approximate the decision boundaries for 4+12+16 APSK symbols, and then decide the log likelihood ratio (LLR) value for each bit from the approximated decision boundaries. Although the proposed algorithm shows about 0.6~1.1dB degradation on the error performance compared with the conventional max-log algorithm, it gives a significant result in terms of the computational complexity.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.4
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• pp.443-448
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• 2014

Soft errors in memory devices that caused by radiation are the main threat from a reliability point of view. This threat can be commonly overcome with the combination of SEC (Single-Error Correction) codes and scrubbing technique. The interleaving architecture can give memory devices the ability of tolerating these soft errors, especially against multiple-bit soft errors. And the interleaving distance plays a key role in building the tolerance against multiple-bit soft errors. This paper proposes a reliability model of an interleaved memory device which suffers from multiple-bit soft errors and are protected by a combination of SEC code and scrubbing. The proposed model shows how the interleaving distance works to improve the reliability and can be used to make a decision in determining optimal scrubbing technique to meet the demands in reliability.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1996.06a
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• pp.554-556
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• 1996

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1993.10a
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• pp.157-160
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• 1993

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5A
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• pp.467-474
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• 2007

MB-OFDM (Multiband-orthogonal frequency division multiplexing) UWB (ultra wide band) system uses DCM (dual carrier modulation) scheme to achieve high-data rate transmission. The basic idea of DCM is that to transmit the 4 bits more reliably two 16-QAM (quadrature amplitude modulation) symbols are used and the two 16-QAM sysmbols are allocated to each subcarrier of OFDM with maximum-distance. In the case of using the DCM, if one 16-QAM symbol is broken by deep fadding channel, a receiver can detect the transmitted signal by using another 16-QAM symbol. In the conventional ML(maximum likelihood) decision scheme, since the receiver does not use the CSI (channel state information), loss in diversity can not be reduced. In this paper, we propose improved soft-decision scheme with CSI for higher performance of MB-OFDM UWB systemn.

• The KIPS Transactions:PartC
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• v.11C no.1
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• pp.75-80
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• 2004

An iterative soft-decision decoding algorithm of block codes is proposed. With careful examinations of the first hard-decision decoding result, the candidate codewords are efficiently searched for. An approach to reducing decoding complexity and lowering error probability is to select a small number of candidate codewords. With high probability, we include the codewords which are at the short distance from the received signal. The decoder then computes the distance to each of the candidate codewords and selects the codeword which is the closest. We can search for the candidate codewords which make the error patterns contain the bits with small reliability values. Also, we can reduce the cases that we select the same candidate codeword already searched for. Computer simulation results are presented for (23,12) Golay code. They show that decoding complexity is considerably reduced and the block error probability is lowered.

• Communications for Statistical Applications and Methods
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• v.9 no.2
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• pp.411-423
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• 2002

In this paper, we propose a split criterion for binary decision trees. The proposed criterion selects the optimal split by measuring the prediction success of the candidate splits at a given node. The criterion is shown to have the property of exclusive preference. Examples are given to demonstrate the properties of the criterion.