• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1985.04a
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• pp.6-8
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• 1985

• East Asian mathematical journal
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• v.12 no.2
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• pp.155-162
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• 1996

• East Asian mathematical journal
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• v.12 no.2
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• pp.147-153
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• 1996

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3458-3481
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• 2021

Existing methods for blind identification of linear block codes without a candidate set are mainly built on the Gauss elimination process. However, the fault tolerance will fall short when the intercepted bit error rate (BER) is too high. To address this issue, we apply the reverse algebra approach and propose a novel "two-step-screening" algorithm by solving the linear error equations on the binary Galois field, or GF(2). In the first step, a recursive matrix partition is implemented to solve the system linear error equations where the coefficient matrix is constructed by the full codewords which come from the intercepted noisy bitstream. This process is repeated to derive all those possible parity-checks. In the second step, a check matrix constructed by the intercepted codewords is applied to find the correct parity-checks out of all possible parity-checks solutions. This novel "two-step-screening" algorithm can be used in different codes like Hamming codes, BCH codes, LDPC codes, and quasi-cyclic LDPC codes. The simulation results have shown that it can highly improve the fault tolerance ability compared to the existing Gauss elimination process-based algorithms.

• Earthquakes and Structures
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• v.4 no.3
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• pp.265-283
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• 2013

This research was prompted by the paucity of specific code provisions regarding the design of short columns for shear. The purpose of this paper was to investigate whether the use of the normal shear design procedure of various codes may or may not be applied to reliably calculate the shear strength of short columns. Provisions of the codes American ACI 318M-08, Canadian CSA A23.3-04, Japanese AIJ Guidelines, New Zealand NZS 3101, European EN 1998 (EC8) parts 1 and 3, combined with EN 1992-1-1 (EC2), and draft fib Model Code 2010, as well as a strut-and-tie model are applied on short columns tested under cyclic loading that failed in shear. Actual shear resistances are compared to predictions, and the resulting shortcomings of the codes are identified. EN1998-3 appears to be the only code among those considered that may be reliably applied to estimate the shear resistance of short columns. Further, the proposed strut-and tie model can be a useful tool for the detailed design and assessment of short columns.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1984.10a
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• pp.11-14
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• 1984

When the received sequence is not identical to the transmitted code word due to the channel nose effect, it is necessary to detect and correct errors. In this paper, it is shown how to construct the encoder and the decoder using cyclic product codes. this system combines random and burst error correction and is easily decodable. Performance has been obtained as expected.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.2
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• pp.1-10
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• 1997

In this paper, an improved lower bound on the burst-error correcting capability of th ecyclic product code is presented and through the analysis of this new bound clustered cyclic product (CCP abbr.)code is proposed. The CCP code, to improve the burst-error correcting capability, combines the idea of clustering and the transmission method of cyclic product code. That is, a cluster which is defined in this paper as a group of consecutive code symbols is employed as a new transmission unit to the code array transmission of cyclic product code. the burst-error correcting capability of the CCP code is improved without a loss in the random-error correcting capability and performance comparison in the digital video camera records (DVCR) system shows the superiority of the proposed CCP code over conventional product codes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2637-2642
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• 2015

The low-density parity check(LDPC) code is being widely used due to its outperformed error-correction ability. The decoder of the quasi-cyclic LDPC(QC-LDPC) codes, a kind of LDPC codes, requires a multi-size cyclic shifter(MSCS) performing rotation of various sizes. The MSCS can be implemented with a Benes network, which requires a $3{\times}3$ switch if the number of data to be rotated is a multiple of 3. This paper proposes a control signal generation with lower complexity and a faster $3{\times}3$ switch. For the experiment, the proposed schemes are applied to the MSCS of an IEEE 802.16e WiMAX QC-LDPC code decoder. The result shows that the delay is reduced by about 8.7%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.7
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• pp.3156-3167
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• 2020

One drawback of polar codes is that they are not universal, that is, to achieve optimal performance, different polar codes are required for different kinds of channel. This paper proposes a polar code construction scheme for Nakagami-m fading channel. The scheme fully considers the characteristics of Nakagami-m fading channel, and uses the optimized Bhattacharyya parameter bounds. The constructed code is applied to an orthogonal frequency division multiplexing (OFDM) system over Nakagami-m fading channel to prove the performance of polar code. Simulation result shows the proposed codes can get excellent bit error rate (BER) performance with successive cancellation list (SCL) decoding. For example, the designed polar code with cyclic redundancy check (CRC) aided SCL (L = 8) decoding achieves 1.1dB of gain over LDPC at average BER about 10^-5 under 4-quadrature amplitude modulation (4QAM) while the code length is 1024, rate is 0.5.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.5
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• pp.1035-1040
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• 2009

We propose a new encoder/decoders based on an tune able wavelength converter(TWC) and an arrayed waveguide grating(AWG) router for large capacity optical CDMA networks. The proposed encoder/decoder treats codewords of wavelength/time 2-D code simultaneously using the dynamic code allocation property of the TWC and the cyclic property of the AWG router, and multiple subscribers can share the encoder/decoder in networks. Feasibility of the structure of the proposed encoder/decoder for dynamic code allocation is tested through simulations using two wavelength/time 2-D codes, which are the generalized multi-wavelength prime code(GMWPC) and the generalized multi-wavelength Reed-Solomon code(GMWRSC). Test results show that the proposed encoder/decoder can increase the channel efficiency not only by increasing the number of simultaneous users without any multiple-access interference but by using a relatively short length CDMA codes.