• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.4
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• pp.803-812
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• 2018

The Morse code was firstly used for a wire telegraph service on May 1884 in USA. After about 10 years Korean researchers developed the Morse code in 1884 and the Morse code was firstly introduced in Korea for the wire telegraph service in September 1885. For about 130 years later, the Hangul Jamo Morse code has been used without any serious modification up to now. The Morse code is the variable length code system which each codes have a different code length. The related reference shows that English alphabet Morse code was applied in the coding theory. However, a result of analysis showed that the Hangul Jamo Morse code was not applied in the coding theory as the english alphabet code system. This paper presents the analysis result of Hangul Jamo Morse code according to the variable length coding theory. As a result of the analysis, when Hangul Jamo are coded with application of the variable length coding theory, the transmission data rate could be increased up to 25% compare to the existing code system. This paper shows a new Hangul Jamo Morse code system based on the analysis result.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.645-648
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• 2004

In this paper, we drive a theoretical performance of complementary code keying (CCK) codes on additive white Gaussian noise (AWGN) channel. The CCK codes can be demodulated by the optimal maximum likelihood decoding method and sub-optimal correlation magnitude decoding algorithm. We calculate the bit error rate (BER) and symbol or codeword error rate (SER) of the CCK codes using the above mentioned two decoding algorithms. To derive the error performance, we use the weigh distributions and cross-correlation distributions of CCK codes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.724-727
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• 1995

Dynamic deformation behavior under the high strain rate loading condition obtained with the aid of Split Hopkinson Pressure Bar(SHPB) technique is simulated by DYNA2D (an hydrodynamic code). A constitutive equation such as Johnson-Cook model is used by adjusting various parameters to fit experimentally determined dynamic stress-strain relationship.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.10
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• pp.2653-2659
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• 1996

In this paper, DC-free and minimum bandwidth binary line codes with look-up table are proposed and their performances are analyzed. As results of performance analysis, the proposed codes are shown to have spectral nulls at DC and Nyquist frequency. Among the proposed codes, binary line codes of which both codeword digital sum and alternating digital sum are zero have lower code rate but better spectral characteristics. Furthermore, binary line codes which consist of all codewords including those with nonzero digital sum and alternating digital sum have worese spectral characteristics but higher code rate.

• Journal of the Semiconductor & Display Technology
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• v.8 no.1
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• pp.19-25
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• 2009

Abstract JPEG2000 achieve quality scalability through the rate control method used in the encoding process, which embeds quality layers to the code-stream. This architecture might raise two drawbacks. First, when the coding process finishes, the number and bit-rates of quality layers are fixed, causing a lack of quality scalability to code-stream encoded with a single or few quality layers. Second, in Post compression rate distortion (PCRD) the bit streams after the truncation points discarded. Therefore, computational power for the discarded bit streams is wasted. For solving of problem, through bit rate control, there are many researches. Each proposed algorithms have specially target feature that is improved performance like reducing computational power. Research results have strength and weakness. For the mean time, research contents are reviewed and compared, so we proposed research direction in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.4
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• pp.379-386
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• 2016

Puncturing is the most common way of increasing the rate of convolutional codes. The puncturing process is done to the original code called the mother code by a specific puncturing pattern. In this article, we investigate into the question whether any convolutional code is obtainable by puncturing some (n, 1) mother codes. We present two sufficient conditions for the mother code and the puncturing pattern to satisfy in order that the punctured code is equivalent to the given (N, K) convolutional code.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.2C
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• pp.168-172
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• 2012

An UHF RFID tag is designed and fabricated using the national code in a bar-code with conductive ink. The bar-code sample was taken from a general bar-code from a general box. The conductivity of the conductive ink was measured, and the measured conductivity was used for the simulation tool to design the printed bar-code shape tag antenna. The tag antenna was fabricated using T-matching to reduce the size of the tag, and the bar-code tag antenna is recognized by both a general bar-code reader and an UHF RFID reader. The input reflection coefficient characteristic, the reading range pattern and the reading rate of the tag antenna are measured.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.959-962
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• 2001

Turbo codes of long block sizes have been known to show very good performance in an AWGN channel and the turbo code has been strongly recommended as error correction code for IMT-2000 in 3GPP(3rd Generation Partnership Project). Recently, turbo codes of short block sizes suitable for real time communication systems have attracted a lot of attention. Thus, in this paper we consider the turbo code of 1/3 code rate and short frame size of 192 bits in ITU-R channel model. We analyzed the performance of W-CDMA systems of 10MHz bandwidths employing RAKE receiver with not only MRC diversity but also turbo code.

• Journal of electromagnetic engineering and science
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• v.7 no.1
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• pp.1-6
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• 2007

Recently, Mc(Multi-code) modulation/demodulation(modem) technique has been explored for high speed data transmission in wireless environment. The conventional Mc modem generates some side effects such as allocating Walsh codes, which motivates to propose a novel Mc modem method with sub-code. Our proposed system should expanded the size of sub-code to provide high-rate data transmission, which also affect adversely to the performance of the system with high PAPR(Peak to Average Power Ratio). Thus, in this paper, we propose a novel pre-coded Multi-Dimensional HCOC(High Capacity Orthogonal Code) Mc modem technique to reduce the high PAPR, which enables the performance improvement. This proposed system can be easily designed by concatenating HCOC Mc modem with the generic Mc modem. The pre-coding technique that is used in this paper is CAC(Constant Amplitude Coding), that helps the system maintain the constant transmission power and reduce the maximum transmission power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7C
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• pp.659-664
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• 2006

We propose two error correcting algorithms for high-density optical storage systems. The first algorithm reduces the false-erasure declaration by reducing the sensitivity on random errors and increases the code rate using a simple erasure indication method. The second one exploits just the known indicator flag instead of error correcting code such as Reed-Solomon(RS) code. The proposed algorithms are superior to the error correcting algorithms of conventional systems such as DVD and BD.