• 한국위성정보통신학회논문지
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• 제9권2호
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• pp.110-113
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• 2014

본 논문에서는 가우시안 이진 대칭 채널에서 쇄상부호를 사용할 때의 최적 내 외 부호율에 관하여 연구한다. 쇄상부호의 전체 부호율이 고정되어 있을 때, 내 부호율이 감소할수록 내 부호의 오류 검출 능력은 향상되지만, 반대로 외 부호의 오류 정정 능력은 감소하게 된다. 이러한 trade-off 관계를 이용하여 본 논문에서는 쇄상부호의 최대 성능 이득을 얻기 위한 내 부호와 외 부호에의 최적의 중복(redundancy) 분포에 관하여 연구한다. 분석한 결과, 가우시안 이진 대칭 채널에서는 외 부호화율을 최소화하고 내 부호화율을 최대화함으로써 전체 쇄상부호 시스템의 성능을 극대화 시킬 수 있음을 알 수 있었다.

• 패션비즈니스
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• 제21권3호
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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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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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

• 한국정보전자통신기술학회논문지
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• 제15권4호
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• pp.230-236
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• 2022

본 논문에서는 확산기반 분자통신 채널에서 랜덤오류와 ISI에 의한 오류 모두에 효율적인 직렬연결 부호를 제안하였다. ISI 제거를 위해 설계된 ISI 완화 부호와 랜덤오류에 강한 ISI 해밍부호를 결합하여 직렬연결 부호를 구성하였으며, 시뮬레이션을 통해 오율 성능을 분석하였다. 방사 분자수 M=1,200 이상인 채널 환경의 경우 직렬연결 부호의 오율 성능은 ISI에 강한 ISI 완화부호의 오율 성능을 따라가며, M=600 이하의 채널 환경에서는 랜덤오류에 강한 ISI 해밍부호의 오율 성능을 따라가고 있음을 알 수 있다. M=600~1,200의 구간에서 직렬연결 부호는 가장 우수한 오율 성능을 보여주는데 이는 랜덤오류와 ISI에 의한 오류가 병존하는 구간에서 두 오류 모두를 정정할 수 있기 때문인 것으로 분석된다. M=800 이하의 경우 직렬연결 부호와 ISI 완화부호의 오율은 평균적으로 약 1.0×10^-1 의 오율 격차를 보여줌을 알 수 있었다.

• 대한전자공학회논문지SD
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• 제45권3호
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• pp.29-35
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• 2008

고효율의 d = 3인 6-ary runlength-limited code를 연구하였다. Rate가 6/7일 경우 98.87%의 효율을 얻을 수 있었고 rate가 13/15일 경우 Shannon capacity에 근접하는 무려 99.95%의 효율을 얻을 수 있었다. 또한 6-ary RLL code를 효과적으로 검출하기 위한 partial response mode에 관하여 고찰하였다.

• 한국통신학회논문지
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• 제31권11C호
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• pp.1037-1043
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• 2006

본 논문에서는 차세대 대용량 데이터 저장장치로 부각되고 있는 홀로그래픽 데이터 저장장치를 위한 2차원 변조코드를 제안한다. 단위 면적당 기록 밀도의 증가로 인한 인접 심볼간 간섭과 3차원적인 홀그래픽 저장으로 인한 페이지간 섭 등에 강인한 성능을 갖도록 같은 페이지 내의 1과 0의 개수가 거의 동일하도록 설계하였으며, 또 가능한 많은 1과 0의 천이가 일어나도록 설계하였다. 제안된 코드의 코드율은 5/9로서 기존의 4/9 코드보다 25%의 코드율 개선을 하였다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1995년도 학술대회
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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.

• 한국정밀공학회지
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• 제17권5호
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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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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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.