• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.4
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• pp.347-356
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• 1987

This paper is to propose a new line code suitable for a high speed unipolar pulse transmission system, such as a high speed optical digital transmission system. The original information speed can be converted into the transmission speed $\frac{(m+1)}{m}$ by the speed converter. Then this code, named mBiZ code, is generated by means of an Exclusive NOR between the bit stream inserted a space into every m bits and the bit stream delayed by the time slot allocated a single bit at the output coded sequence. Therefore, a mBiZ code can reduce a redundancy in the line code for transmission and its conversion circuits can be devised easily. The mBiZ code can also suppress undesirable long consecuitive identical digits and make line code balance in the mark and space ratio. Therefore, high frequency and low frequency components in power spectrum of a mBiZ code can be suppessed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.4
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• pp.230-236
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• 2022

In this paper, we propose an efficient concatenated code for both random and ISI errors on diffusion-based molecular communication channels. The proposed concatenated code was constructed by combining the ISI-mitigating code designed for ISI mitigation and the ISI-Hamming code strong against random errors, and the BER(bit error rate) performance was analyzed through simulation. In the case of the above M=1,200 channel environment, it was found that the error rate performance of the concatenated code follows the error rate performance of the ISI-mitigating code, which is strong against ISI, and follows the error rate performance of the ISI-Hamming code, which is strong against random errors, in the channel environment below M=600. In M=600~1,200, the concatenated code shows the best error rate performance among those of three codes, which is analyzed because it can correct both random errors and errors caused by ISI. In the following cases of below M=800, it can be seen that the error rate of the concatenated code and the ISI-mitigating code shows an error rate difference of about 1.0×10^-1 on average.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.317-320
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• 2016

In embedded system, if firmware code is opened by other company, must devise hardware copy prevention. That guard valuable product. Not used security IC, Suggested platform is source code open method that prevent core code and hardware copy. And that open firmware code for other company programmer. Suggest system security platform based on Corex-M3. that consist of IAP(In-application programing) and APP(Applicataion). IAP contain core code and security confirm code. APP is implement by other company developer using core function prototype.

• Fire Science and Engineering
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• v.25 no.1
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• pp.1-6
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• 2011

An evacuation simulation was carried out to confirm evacuation efficiency for stair width and problems in calculation of occupant load for high-rise buildings. The evacuation time and number of evacuated persons from a 39 story condominium-mercantile building were calculated by using Simulex for stair widths of 1.2 m, 1.5 m, and 1.8 m. The total occupant load based on the Korean code was higher than the number of actual residents by 2.3 times, and that based on the NFPA 101 Life Safety Code by 2.6 times, respectively. For the occupant load based on the Korean code, smaller stair width resulted in lower evacuation efficiencies due to bottlenecks in egress. For the actual residents and NFPA code-based occupant load, a high evacuation efficiency and negligible effects of the stair width on evacuation efficiency were confirmed. It was shown that there was a bottleneck even at the stair width of 1.8 m for the Korean code-based occupants, while the stair width of 1.2 m provided safe egress to the actual residents or NFPA code-based occupants. This recommended further studies on possibility of lowering the level of the Korean code in calculation of the occupant load.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.959-966
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• 2015

In this paper, we propose an indoor visible light communication(VLC) localization using Walsh code which can identify overlapped signals transmitted from the different LED sources as each of orthogonal signal at a receiver and using Manchester code which can eliminate the flicker of LED light and maintain a constant brightness. The proposed system can estimate the relative position of the receiver by using Lambertian radiation properties and trilateration method that are applied to the location information of fixed LED sources and the received signals from them. In order to verify the feasibility of the proposed system, we carried out the simulation in an indoor space with $6{\times}6{\times}1.5m^3$ installed LED lamps of 16. The simulation result shows that the proposed method achieves an average positioning error of 0.0536 m and a maximum positioning error of 0.2977 m.

• Journal of applied mathematics & informatics
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• v.26 no.1_2
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• pp.107-120
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• 2008

There has been a recent growth of interest in codes with respect to a newly defined non-Hamming metric grown as the Rosenbloom-Tsfasman metric (RT, or $\rho$, in short). In this paper, the definitions of the Lee complete $\rho$ weight enumerator and the exact complete $\rho$ weight enumerator of a code over $M_n_\times_s(Z_4)$ are given, and the MacWilliams identities with respect to this RT metric for the two weight enumerators of a linear code over $M_n_\times_s(Z_4)$ are proven too. At last, we also prove that the MacWilliams identities for the Lee and exact complete $\rho$ weight enumerators of a linear code over $M_n_\times_s(Z_4)$ are the generalizations of the MacWilliams identities for the Lee and complete weight enumerators of the corresponding code over $Z_4$.

• ETRI Journal
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• v.28 no.1
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• pp.95-98
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• 2006

In this letter, a novel M-ary code-selected direct sequence (DS) ultra-wideband (UWB) communication system is presented. Our purpose is to achieve a high data rate by an M-ary code-selected direct sequence bipolar pulse amplitude modulation (MCSDS-BPAM) scheme. In this system, a particular DS code sequence is selected by the $log_2M$/2 bits from the DS gold code set. This scheme can accomplish both a high data rate without increasing the system bandwidth or changing the pulse shape and improve the BER with an increase of modulation level M even at a lower signal-to-noise ratio (SNR). The receiver signal processing algorithm is given for an MCSDS-BPAM UWB system over an ideal AWGN channel and correlation receivers.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.117-123
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• 2013

By calculating the spectral efficiency of symmetric balance incomplete block design(BIBD) codes satisfying BER=$10^{-9}$, it can be found that ideal BIBD code design with m=2 and various q's is effective when effective power is high($P_{sr}=-10$ dBm). But BIBD code design with q > 2 and various m's can be effective when effective power is low($P_{sr}=-25$ dBm).

• Structural Monitoring and Maintenance
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• v.6 no.1
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• pp.67-84
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• 2019

Digital Image Correlation technique (DIC) is a non-contact optical method for rapid structural health monitoring of critical infrastructure. An innovative approach to DIC is presented using QR (Quick Response) code based random speckle pattern. Reinforced Cement Concrete (RCC) beams of size $1800mm{\times}150mm{\times}200mm$ are tested in flexure. DIC is used to extract Moment (M) - Curvature (${\kappa}$) relationships using random speckle patterns and QR code based random speckle patterns. The QR code based random speckle pattern is evaluated for 2D DIC measurements and the QR code speckle pattern performs satisfactorily in comparison with random speckle pattern when considered in the context of serving a dual purpose. Characteristics of QR code based random speckle pattern are quantified and its applicability to DIC is explored. The ultimate moment-curvature values computed from the QR code based random speckled pattern are found to be in good agreement with conventional measurements. QR code encrypts the structural information which enables integration with building information modelling (BIM).