• Journal of Communications and Networks
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• v.10 no.2
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• pp.186-193
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• 2008

A two-hop multiple-input multiple-output (MIMO) relay network which comprises a multiple antenna source, an amplify-and-forward MIMO relay and many potential users are studied in this paper. Consider the achievable sum rate as the performance metric, a joint design method for the processing units of the BS and relay node is proposed. The optimal structures are given, which decompose the multiuser MIMO relay channel into several parallel single-input single-output relay channels. With these structures, the signal-to-noise ratio at the destination users is derived; and the power allocation is proved to be a convex problem. We also show that high sum rate can be achieved by pairing each link according to its magnitude. The sum rate of three broadcast strategies, time division multiple access (TDMA) to the strongest user, dirty paper coding (DPC), and beamforming (BF) are investigated. The sum rate bounds of these strategies and the sum capacity (achieved by DPC) gain over TDMA and BF are given. With these results, it can be easily obtained that how far away TDMA and BF are from being optimal in terms of the achievable sum rate.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.371-376
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• 2012

In this paper, we propose a new data coding method and its circuits for minimizing data transition in text image. The proposed circuits can solve the synchronization problem between input data and output data in the modified LVDS algorithm. And the proposed algorithm is allowed to transmit two data signals through additional serial data coding method in order to minimize the data transition in text image and can reduce the operating frequency to a half. Thus, we can solve EMI(Electro-Magnetic Interface) problem and reduce the power consumption. The simulation results show that the proposed algorithm and circuits can provide an enhanced data transition minimization in text image and solve the synchronization problem between input data and output data.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.427-430
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• 2005

A multi-code biorthogonal code keying (MBCK) system consists of multiple waveform coding blocks, and the sum of output codewords is transmitted. Drawback of MBCK is that it requires amplifier with high linearity because its output symbol is multi-level. MBCK with constant amplitude precoding block (CA-MBCK) has been proposed, which guarantees sum of orthogonal codes to have constant amplitude. The precoding block in CA-MBCK is a redundant waveform coder whose input bits are generated by processing the information bits. Redundant bits of constant amplitude coded CA-MBCK are not only used to make constant amplitude signal but also used to improve the BER performance at the receiver. In this paper, we proposed a transmission scheme which combines CA-MBCK with $Q^2PSK$ modulation to improve bandwidth efficiency of CA-MBCK and also uses chip interleaving to maintain a constant amplitude feature of CA-MBCK. bandwidth efficiency of a proposed transmission scheme is increased fourfold. And the BER performance of the scheme is same as that of CA-MBCK.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1306-1313
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• 2018

The randomness and incipient nature of certain faults in reactor systems warrant a robust and dynamic detection mechanism. Existing models and methods for fault diagnosis using different mathematical/statistical inferences lack incipient and novel faults detection capability. To this end, we propose a fault diagnosis method that utilizes the flexibility of data-driven Support Vector Machine (SVM) for component-level fault diagnosis. The technique integrates separately-built, separately-trained, specialized SVM modules capable of component-level fault diagnosis into a coherent intelligent system, with each SVM module monitoring sub-units of the reactor coolant system. To evaluate the model, marginal faults selected from the failure mode and effect analysis (FMEA) are simulated in the steam generator and pressure boundary of the Chinese CNP300 PWR (Qinshan I NPP) reactor coolant system, using a best-estimate thermal-hydraulic code, RELAP5/SCDAP Mod4.0. Multiclass SVM model is trained with component level parameters that represent the steady state and selected faults in the components. For optimization purposes, we considered and compared the performances of different multiclass models in MATLAB, using different coding matrices, as well as different kernel functions on the representative data derived from the simulation of Qinshan I NPP. An optimum predictive model - the Error Correcting Output Code (ECOC) with TenaryComplete coding matrix - was obtained from experiments, and utilized to diagnose the incipient faults. Some of the important diagnostic results and heuristic model evaluation methods are presented in this paper.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.614-622
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• 2015

Binary MQ arithmetic coding is widely used recently as a basic entropy coder in multimedia coding system. MQ coder esteems high in compression efficiency to be used in JBIG2 and JPEG2000. The importance of arithmetic coding is increasing after it is adopted as an unique entropy coder in HEVC standard. In the binary MQ coder, arithmetic approximation without multiplication is used in the process of recursive subdivision of range interval. Because of the MPS/LPS exchange activity happened in MQ coder, output byte tends to increase. This paper proposes an enhanced binary MQ arithmetic coder to make use of a lookup table for AQe using quantization skill in order to reduce the deficiency. Experimental results show that about 4% improvement of compression in case of JBIG2 for bi-level image compression standard. And also, about 1% improvement of compression ratio is obtained in case of lossless JPEG2000 coding. For the lossy JPEG2000 coding, about 1% improvement of PSNR at the same compression ratio. Additionally, computational complexity is not increasing.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.32 no.2
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• pp.87-93
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• 2021

There are a number of voice analysis programs around the world. Domestic voice analysis is performed by relying heavily on specific commercial program. We intend to develop coding for voice analysis using Praat and apply it to clinical practice. This study consisted of Experiment 1 and Experiment 2. Experiment 1 was the development of automated voice analysis coding based on Praat. The coding was largely divided into a recording, an analysis, and a storage section. Experiment 2 was applied to the voice analysis of 2 male patients pre- and post-operation with this coding. The analysis parameters of this coding provided 26 parameters for vowel /a/, nine parameters for sentence analysis, and a total of 4 parameters for voice range profile analysis. In two male patients, the pitch and the intensity increased, the voice quality improved, and the sentence length decreased after surgery. The coding was well made, so the output was good in real time. The code is automated as much as possible to block manual errors and increases convenience and efficiency by generating the result sheet in real time.

• The Mathematical Education
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• v.60 no.4
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• pp.467-491
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• 2021

This study is a study on the coding mathematics curriculum that converges elementary and middle school mathematics and information subjects and a minimum coding game-based education method for this. For the past 3 years, the coding mathematics curriculum and educational methods to effectively operate the curriculum were studied by applying them to 6th graders of elementary school and 1st graders of middle school. As a result of the first year of research, the coding mathematics curriculum was modified to a coding environment including the mathematical concept of a three-dimensional coordinate space, and the three-dimensional object was improved to be output as a real 3D print. As a result of the 2nd year study, it was improved so that even low-level students can build buildings by introducing different level commands for each component of the building so that self-directed learning is possible. As a result of the 3rd year study, a teaching-learning strategy based on a minimal coding game was designed to induce an increase in the level of computational thinking, and evaluation and feedback for diagnosing computational thinking were developed. Educational methods to promote self-directed learning and computing thinking ability, and researched coding mathematics curriculum are meaningful for the research and practice of the convergence education of school mathematics and informatics.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.1-8
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• 2010

Multi antenna techniques using space-time codes can achieve diversity gains in a multi-path environment without additional bandwidth requirement. Most of the 4G candidate standards including the IEEE 802.16e adopt multi-input multi-output (MIMO) schemes to achieve either high throughput performance or diversity gains. In these 4G candidate standards, turbo codes using an iterative decoder with soft input soft output are used to overcome serious channel fading. For this reason, the estimated signal values from MIMO detectors should be soft decision detection values. In this paper, we propose efficient methods to estimate soft decision detection values for various space time coding schemes, and provide the simulation results of turbo coded space time coding scheme over an IEEE 802.16e link.

• Journal of Communications and Networks
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• v.13 no.3
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• pp.232-239
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• 2011

This paper investigates the user selection problem of successive zero-forcing precoded multiuser multiple-input multiple-output (MU-MIMO) downlink systems, in which the base station and mobile receivers are equipped with multiple antennas. Assuming full knowledge of the channel state information at the transmitter, dirty paper coding (DPC) is an optimal precoding strategy, but practical implementation is difficult because of its excessive complexity. As a suboptimal DPC solution, successive zero-forcing DPC (SZF-DPC) was recently proposed; it employs partial interference cancellation at the transmitter with dirty paper encoding. Because of a dimensionality constraint, the base station may select a subset of users to serve in order to maximize the total throughput. The exhaustive search algorithm is optimal; however, its computational complexity is prohibitive. In this paper, we develop two low-complexity user scheduling algorithms to maximize the sum rate capacity of MU-MIMO systems with SZF-DPC. Both algorithms add one user at a time. The first algorithm selects the user with the maximum product of the maximum column norm and maximum eigenvalue. The second algorithm selects the user with the maximum product of the minimum column norm and minimum eigenvalue. Simulation results demonstrate that the second algorithm achieves a performance similar to that of a previously proposed capacity-based selection algorithm at a high signal-to-noise (SNR), and the first algorithm achieves performance very similar to that of a capacity-based algorithm at a low SNR, but both do so with much lower complexity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1A
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• pp.50-58
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• 2008

The use of space-division multiple access(SDMA) in the downlink of multiuser multi-input/multi-output(MIMO) wireless transmission systems can provide substantial gains in system throughput. When the channel state information(CSI) is available at the transmitter, a considerable performance improvement can be attained by adapting the transmission rates to the reported CSI. In addition, to combat frequency selective fadings in wideband wireless channels, bit-interleaved coded OFDM(BIC-OFDM) modulation schemes are employed to provide reliable packet delivery by utilizing frequency diversity through channel coding. In this paper, we propose an adaptive modulation and coding(AMC) scheme combined with an opportunistic scheduling technique for the MIMO BIC-OFDM with bandwidth-limited feedback channels. The proposed scheme enhances the link performance by exploiting both the frequency diversity and the multiuser diversity. To reduce the feedback information, the proposed AMC scheme employs rate adaptation methods based on an OFDM symbol rather than on the whole subchannels. Simulation results show that the proposed scheme exhibits a substantial performance gain with a reasonable complexity over single antenna systems.