• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10A
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• pp.968-975
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• 2006

Research about the mode of MIMO that can get a coding benefit at the same time with a diversity benefit using a multiple antenna at the fading channel for a high-speed data transmission have been processed actively But the analysis about the interference of UWB system comes not to consist yet. So this paper analyzed the performance of the interference of UWB system to SFBC-OFDM and SFTC-OFDM system that applied a space block code which has a space diversity characteristic to OFDM system at MIMO channel. We shelved the performance that SFTC-OFDM system is robuster than SFBC-OFDM system under MB-OFDM UWB Interference.

• Journal of Broadcast Engineering
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• v.15 no.4
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• pp.547-554
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• 2010

In this paper, we propose transmission systems for ultra high definition television (UHDTV) through terrestrial transmission by applying the multi-input multi-output (MIMO) technology. The space time block code, hybrid STBC, V-BLAST and linear dis- persion code are considered to support a high data rate of the UHDTV system. The performance of proposed MIMO systems are evaluated through computer simulations. Then we suggest MIMO parameters, number of antennas and optimal transmission scheme to achieve the transmission rate of the UHDTV system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7C
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• pp.617-623
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• 2005

In this paper, new space-time block codes achieving full rate and full diversity for QAM and quasi-static Rayleigh fading channels when using 3 transmit antennas are proposed. These codes are constructed by serially concatenating the constellation rotating precoders with the Alamouti scheme like the conventional A-ST-CR code Computer simulations show that all of the proposed codes achieve the coding gains greater than the existing ST-CR code, in which the best has approximately 1.5dB and 3dB larger coding gains than the ST-CR code for QPSK and 16-QAM, respectively, at average SER= 10$^{-5}$.

• Journal of Communications and Networks
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• v.18 no.1
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• pp.27-39
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• 2016

This paper derives and analyzes a novel block fast Fourier transform (FFT) based joint detection algorithm. The paper compares the performance and complexity of the novel block-FFT based joint detector to that of the Cholesky based joint detector and single user detection algorithms. The novel algorithm can operate at chip rate sampling, as well as higher sampling rates. For the performance/complexity analysis, the time division duplex (TDD) mode of a wideband code division multiplex access (WCDMA) is considered. The results indicate that the performance of the fast FFT based joint detector is comparable to that of the Cholesky based joint detector, and much superior to that of single user detection algorithms. On the other hand, the complexity of the fast FFT based joint detector is significantly lower than that of the Cholesky based joint detector and less than that of the single user detection algorithms. For the Cholesky based joint detector, the approximate Cholesky decomposition is applied. Moreover, the novel method can also be applied to any generic multiple-input-multiple-output (MIMO) system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5776-5782
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• 2014

Relay-assisted wireless communication systems have been studied widely to cope with shadow areas and extend the cell coverage. This paper proposes a space-frequency (SF) block coded single carrier-frequency division multiple access (SC-FDMA) transmission system in a relaying multi-path shadow area and present the performance comparison of SC-FDMA systems based on the signal-to-noise power ratio (SNR) between a relay and a destination station. The performance of relaying SC-FDMA systems can be improved by applying SF block code to the recovered signals of relays before re-transmitting them. The simulation result showed that the SNR performance of the proposed SF block coded relaying SC-FDMA system was approximately 5 dB better than the SNR performance of the single-path relaying SC-FDMA system at a symbol error rate (SER) of $10^{-2}$.

• Journal of Creative Information Culture
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• v.6 no.1
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• pp.31-40
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• 2020

The purpose of this study is to statistically analyze the correlation between block-coding software education and the resilience of elementary school students in order to research the significance of software education. In this study, 61 fourth grade students at an elementary school in Incheon were pre-tested for resilience. A block-coding education program from a nonprofit organization called code.org was used at the learner's level. 15 periods of classes and post-test were conducted to analyze the improvement of resilience. This study finds that control and positivity out of the three parts of resilience(control, positivity, sociality) of the students who took the block-coding classes improved statistically significantly as well as the overall score did too. This suggests that software education can foster not only students' computational thinking skills, but also their resilience, the power to live their lives positively and flexibly.

• Bulletin of the Korean Space Science Society
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• 2006.10a
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• pp.148-148
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• 2006

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8C
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• pp.763-770
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• 2006

In this paper, a variable Reed-Solomon(RS) decoder with erasure decoding functionality is designed based on the modified Euclid's algorithm(MEA). The variability of the decoder is implemented through shortening and puncturing based on the RS(124, 108, 8) code, other than the primitive RS(255, 239, 8) code. This leads to shortening the decoding latency. The decoder performs 4-step pipelined operation, where each step is designed to be clocked by an independent clock. Thus by using a faster clock for the MEA block, the complexity and the decoding latency can be reduced. It can support both continuous- and burst-mode decoding. It has been designed in VHDL and synthesized in an FPGA chip, consuming 3,717 logic cells and 2,048-bit memories. The maximum decoding throughput is 33 MByte/sec.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.677-690
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• 1995

In this paper, we propose the high efficiency data compression capable of error control using block-sorting, move to front(MTF) and arithmetic code with variable length in to fixed out. First, the substring with is parsed into length N is shifted one by one symbol. The cyclic shifted rows are sorted in lexicographical order. Second, the MTF technique is applied to get the reference of locality in the sorted substring. Then the preprocessed sequence is coded using VF(variable to fixed) arithmetic code which can be limited the error propagation in one codeword. The key point is how to split the fixed length codeword in proportion to symbol probabilities in VF arithmetic code. We develop the new VF arithmetic coding that split completely the codeword set for arbitrary source alphabet. In addition to, an extended representation for symbol probability is designed by using recursive Gray conversion. The performance of proposed method is compared with other well-known source coding methods with respect to entropy, compression ratio and coding times.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1462-1470
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• 2003

According to the necessity about information security as well as the advance of IT system and the spread of the Internet, a variety of cryptography algorithms are being developed and put to practical use. In addition the technique about cryptography attack also is advanced, and the algorithms which are strong against its attack are being studied. If the linear transformation matrix in the block cipher algorithm such as Substitution Permutation Networks(SPN) produces the Maximum Distance Separable(MDS) code, it has strong characteristics against the differential attack and linear attack. In this paper, we propose a new algorithm which cm estimate that the linear transformation matrix produces the MDS code. The elements of input code of linear transformation matrix over GF$({2_n})$ can be interpreted as variables. One of variables is transformed as an algebraic formula with the other variables, with applying the formula to the matrix the variables are eliminated one by one. If the number of variables is 1 and the all of coefficient of variable is non zero, then the linear transformation matrix produces the MDS code. The proposed algorithm reduces the calculation time greatly by diminishing the number of multiply and reciprocal operation compared with the conventional algorithm which is designed to know whether the every square submatrix is nonsingular.