• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.110-113
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• 2014

In this paper, we address a problem of finding the optimum inner and outer code rates for a concatenated code in Gaussian binary symmetric channels. Clearly, as the inner code rate decreases, the error detection capability of the inner code increases. However, decreasing the inner code rate implies a decrease in error-correction capability of the outer code when overall code rate is fixed. With this notion in mind, we examine the optimum distribution of redundancy on the outer and inner codes to achieve a maximum performance gain in the concatenated coding scheme. Our analysis shows that the maximum coding gain can be obtained when the inner code rate is maximized and the outer code rate is minimized under the constraint of total code rate is fixed.

• Journal of Fashion Business
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• v.21 no.3
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• pp.14-28
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• 2017

This purpose of this study to analyze effect material properties have on change in QR code recognition rate according to change of materials by comparing recognition rate of color QR code. QR code applied to textile materials has the advantage of being washable and being applicable to lost child prevention goods or clothes or a person with dementia through record of information relating to the material or input of additional information, differently from QR code printed on the conventional paper. An effective method of entering QR code in textile materials is Digital Textile Printing(DTP), that facilitates printing by rapidly applying diverse information, and small quantity production. It is possible to tailor various QR codes according to use. Regarding samples to use, cotton material used in clothing products and Tyvek material recently applied to clothing and related products were selected. Reactive dyes were used for cotton, pigment was used for Tyvek, and QR code was printed with an inkjet printer by direct printing method. Printing methods and surface textures are different between cotton and Tyvek. It was revealed that consequent print results and results of recognition rate were different. Regarding color to be printed, 2015 S/S - 2017 S/S color presented by Pantone was used. Color combination affected recognition rate of color QR code. Understanding color combination, material properties and print characteristics may be helpful in increasing recognition rate of color QR code, and may contribute to usability of color QR code applied to textile materials in the future.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.297-300
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• 2001

Turbo code shows the great performance near Shannon limit on AWGN channel. Mainly, turbo code has been studied and designed for wireless digital communications. There are recent studies that applies turbo decoder on magnetic recording. Because of the limited capacity of magnetic storages, high rate turbo code is used for magnetic storages. This paper presents some issues on implementing high rate turbo code and structures for designing turbo decoder

• 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.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.3
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• pp.29-35
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• 2008

Very efficient 6-ary runlength-limited codes for a six-level optical recording channel are presented when d = 3. The 6-ary(3, 15) code of rate 6/7 is given achieving coding efficiency of 98.87%. The efficiency of rate 13/15, (3, 20) code is 99.95%, which approaches the Shannon capacity. To increase the accurary of reading 6-ary signal, partial response modes are also investigated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11C
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• pp.1037-1043
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• 2006

In this paper, we introduce a two-dimensional modulation code for holographic data storage systems(HDSS), which is a candidate for the next generation data storage system. The two-dimensional(2D) intersymbol interference(ISI) induces higher bit error rate(BER). The balanced number of zeros(dark) and ones(light) in each page reduces inter-page interference(IPI). The code rate is 519. Although the proposed code has higher code rate than other 2D code with rate 4/9, the BER performances of two codes are similar.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1995.06a
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• pp.59-61
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• 1995

An adaptive code rate change scheme in DS-SSMA systems is proposed. In the proposed scheme, the error correcting code rate is changed according to the channel state, the effective number of users. The channel state is estimated based on retransmission requests. The criterion for the change of the code rate is to maximize the throughput under given error bound.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.5
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• pp.116-123
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• 2000

This paper presents an NC code post-processor that adjusts feedrates to keep the variation of metal removal rate along the tool paths minimum. Metal removal rate is estimated by virtually machining the part, whose surface model is built from a series of NC codes defined in operation plan, with cutting-tool-assembly models, whose geometry are defined in a machining database. The NC code post-processor modifies the feedrates by the adjustment rules, which are based on the machining knowledge for effective machining. This paper illustrates a procedure fur grouping machining conditions and we also show how to determine an adjustment rule for a machining-condition group. An example part was machined and it shows that the variation of cutting force was dramatically reduced after applying the NC code post-processor. The NC code post-processor is expected to increase productivity while maintaining the quality of the machined part.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.233-235
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• 2005

As a class of block codes, LDPC code with any desired code rate and code length is easily constructed. In OFDM system high data transmission is possible, In this paper, we examined the performance of four high-rate(0.75, 0.8, 0.889, 09412) LDPC coded OFDM in image transmission over Rayleigh fading channel. The high-rate of 0.9412 LDPC coded OFDM system obtained about 12dB gain over the OFDM at BER of $10^{-3}$ over Rayleigh fading channel. Also, the PSNR of code rate 0.9412 LDPC coded OFDM system at SNR=10dB is given by 18.8047dB where uncoded OFDM system gives 9.7303 dB.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.37-42
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• 1997

Off-line feed rate scheduling is an advanced methodology to automatically determine optimum feed rates for the optimization of NC code. However, the present feed rate scheduling systems have lim~tations to generate the optimized NC codes because they use the material removal rate or non-generalized cutting force model. In this paper, a feed rate scheduling system based on an improved cutting force model that can predrct cutting forces exactly in general machining was presented. Original blocks of NC code were divided to small ones with the modified feed rates to adjust the peak value of cutting forces to a constant vale. The characteristic of acceleration and deceleration for a given machrne tool was considered when off-line feed rate scheduhng was performed. Software for the NC code optimization was developed and applied to pocket machining simulation.