• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.55-62
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• 2008

Adaptive modulation and Coding(AMC) scheme is promising technique to support the demands for high data rates and wideband proposed for 4G mobile communication system standards. In this paper, adaptive modulation and coding(AMC) based on OFDM system is analyzed through simulation for single user case and compared with SISO-OFDM and SFBC(Space frequency block coding)-OFDM. The performance analysis in terms of capacity for downlink system environments with different values of constellation size under multipath fading channel is done. The adaptive modulation and coding technique is based on perfect estimation channel. It has been observed that SFBC(Space-frequency block coding)-OFDM system gives better performance in terms of capacity.

• International journal of advanced smart convergence
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• v.8 no.4
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• pp.147-153
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• 2019

Recently, the perception of software education, which had been considered as a field of education for programmers in this field, is changing in response to recent changes with the trend of 4th industrial revolution. Major counties competitively invest in software education and the target age group for software education is also on the decline. However, the traditional text-based programing languages such as JAVA and Python, have a high entry barrier. To address the shortcoming, a variety of methods have been recently proposed for the effective software education for kindergarten and elementary school student. In this paper, we propose a robot-based coding education system with steps for coding education for effective software education. The proposed method is divided into three stages, depending on the level of the student being trained in the software coding education to interact with robots. The proposed stages consists of unplugged coding using a remote control, coding using a graphic-based programming language and text- based coding. We conducted an experiment with performing separate missions while providing propoer tutorials for each stage to verify the effectiveness of the proposed software education system.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.193-195
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• 2008

Safety is important factor in railway system. Now most of the electric and electronic system which is applied in railway system is the embedded system which software is used. The constitution rate of software which is involved in railway system is gradually increasing. Most of the software which is used in railway system is implemented by the software developer. Thus the implemented code has different features according to the developer and this may cause the bad effect on the software's maintenance. International standard IEC 62279 requires an adoption the coding standard to developing the railway software. And it is plan to recommend complying with the coding standard in safety criteria for railway software which is noticed as the regulation of the Korean railway safety law. In this paper, we review the requirement of coding standards which is present in the software criteria for railway software and international standard. Also it investigates the coding standard which is in other safety related industry and presents the effective way to apply the software coding standard to domestic railway industry.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1998.12a
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• pp.537-545
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• 1998

This paper is the research about a joint coding system of source and channel coding using VF(Variable-to-fixed length) arithmetic code and BCH code. We propose a VF arithmetic coding method with EDC( Error Detecting Capability) and a joint coding method in that the VF arithmetic coding method with EDC is combined with BCH code. By combining both the VF arithmetic code with EDC and BCH code. the proposed joint coding method corrects a source codeword with t-errors in decoding of BCH code and carries out a improvement of the EDC of a codeword with more than (t＋1)-errors in decoding of the VF arithmetic coding with EDC. We examine the performance of the proposed method in terms of compression ratio and EDC.

• International journal of advanced smart convergence
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• v.7 no.4
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• pp.128-137
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• 2018

In the programming education, there is a great need of a teaching support system that can support the learner in the programming process regardless of the computer language due to instructor's difficulty of checking the progress of learners in real-time. Its importance is especially important in lower grade coding classes such as in K-12 education because they are not used to coding and so simple problems can be regarded as complex problems. For this, a pilot coding education support system based on Levenshtein distance algorithm which shows learners' progress to given solution in real-time was developed in order to help learners to solve complex problems easily, and the learners' motivation and self-efficacy was measured for estimating the usefulness of developed system targeting elementary school students. When the learners use the developed system, it was found that a statistically significant difference appears in the sub-factors of learning motivation compared with traditional class teaching environments. Among the sub-factors of self-efficacy, the efficacy dimension showed statistically significant difference too.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.3
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• pp.265-270
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• 2004

This paper addresses the effect of group delay in satellite communication system. Phase of signal is distorted by the non-constant group delay. Group delay can be modeled as linear, parabolic and cubic type according to the polynomial characteristic. We investigate BER performance of satellite communication system with each 3 kinds of group delay. As signal bandwidth becomes wider, group delay makes more influence on the signal. BNR performance of satellite communication system is found when data rates are 1Mbps, 4Mbps and 8Mbps. Convolution coding with the code rate of 1/2 or 7/8 is used. At BER =10$\^$-5/, system with group delay needs more SNR of minimum 0.3㏈ to maximum 4.4㏈ than system without group delay. The worst case of BER performance happens in the linear group delay, 7/8 punctured convolution coding and 8 Mbps. The required SNR is increased by 4.4㏈ at this worst case.

• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.559-565
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• 2005

In this paper, we propose a stereoscopic video coding scheme for subway accident monitoring system. The proposed designed for providing flexible video among various displays, such ass control center, station employees and train driver. We uses MPEG-2 standard for coding the left-view sequence and IBMDC coding scheme predicts matching block by interpolating both motion and disparity predicted macroblocks. To provide efficient stereoscopic video service, we define both temporally and spatially scalable layers for each eye's-view by using the concept of Spatio-Temporal scalability. The experimental results show the efficiency of proposed coding scheme by comparison with already known methods and the advantages of disparity estimation in terms of scalability overhead. According to the experimental results, we expect the proposed functionalities will play a key role in establishing highly flexible stereoscopic video codec for ubiquitous display environment where devices and network connections are heterogeneous.

• The Journal of Korean Association of Computer Education
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• v.7 no.4
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• pp.51-60
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• 2004

This paper proposes an automated coding system of Korean standard industry/occupation for census which reduces a lot of cost and labor for manual coding. The proposed system converts natural language responses on survey questionnaires into corresponding numeric codes using information retrieval techniques and document classification algorithm. The system was experimented with 46,762 industry records and occupation 36,286 records using 10-fold cross -validation evaluation method. As experimental results, the system show 87.08% and 66.08% production rates when classifying industry records into level 2 and level 5 codes respectively. The system shows slightly lower performances on occupation code classification. We expect that the system is enough to be used as a semi-automate coding system which can minimize manual coding task or as a verification tool for manual coding results though it has much room to be improved as an automated coding system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.6
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• pp.81-88
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• 2012

Space diversity and space multiplexing gain can be achieved with MIMO system. This paper proposes spatial coding method to MIMO system using data information and antenna selection technique. This technique provides coding gain as well as space diversity gain. For MIMO system with BPSK modulation, BER performance is analyzed and space diversity gains are compared through simulation in terms of data maldistribution degree.

• Journal of Multimedia Information System
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• v.5 no.4
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• pp.273-276
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• 2018

In video compression standards, the entropy coding is essential to the high performance compression because redundancy of data symbols is removed. Binary arithmetic coding is one of high performance entropy coding methods. However, the dependency between consecutive binary symbols prevents improving the throughput. For the throughput enhancement, a new probability model is proposed for encoding multi-symbols at one time. In the proposed method, multi-symbol encoder is implemented with only adders and shifters, and the multiplication table for interval subdivision of binary arithmetic coding is removed. Compared to the compression ratio of CABAC of H.264/AVC, the performance degradation on average is only 1.4% which is negligible.