Error Correction by Redundant Bits in Constant Amplitude Multi-code CDMA

송희근,김성민,김범곤,김동석,고대원,김용철 한국통신학회 2006 韓國通信學會論文誌 Vol.31 No.11

Error Correction by Redundant Bits in Constant Amplitude Multi-code CDMA

송희근,김성만,김범곤,김동석,고대원,김용철,Song, Hee-Keun,Kim, Sung-Man,Kim, Bum-Gon,Kim, Tong-Sok,Ko, Dae-Won,Kim, Yong-Cheol The Korea Institute of Information and Commucation 2006 韓國通信學會論文誌 Vol.31 No.11C

In this paper, we present two methods of correcting bit errors in constant amplitude multi-code (CAMC) CDMA, which uses the redundant bits only. The first method is a parity-based bit correction with hard-decision, where the received signals despread into n two-dimensional structure with both horizontal parity and vertical parity. Then, an erroneous bit is corrected for each $4{\times}4$ pattern. The second method is a turbo decoding, which is modified from the decoding of a single parity check product code (SPCPC). Experimental results show that, in the second method, the redundant bits in CAMC can be fully used for the error correction and so they are not really a loss of channel bandwidth. Hence, CAMC provides both a low peak-to-average power ratio and robustness to bit errors.

ARPS 움직임 추정과 POCS 복원을 동시에 이용하는 HR 영상 재구성

송희근(Heekeun Song),김용철(Yong Cheol Kim) 한국통신학회 2009 韓國通信學會論文誌 Vol.34 No.3

POCS (projection onto convex sets)를 이용하는 고해상도 영상 재구성에서는 재구성 연산 사이에 프레임간 움직임을 추정함으로써 양질의 HR (high resolution) 영상을 얻을 수 있으나, 반복적인 움직임 추정으로 인해 연산량은 증가한다. 본 논문에서는 기존의 ARPS (adaptive rood pattern search) 움직임 추정법을 수정하여 연산량을 줄이면서, 움직임 추정과 POCS 복원을 동시에 수행하는 HR 영상의 재구성 알고리즘을 제안한다. ARPS에서 필요한 기준 움직임의 값으로 POCS 복원의 이전 단계에서 추정한 움직임 벡터의 값과 위상 상관도법으로 얻은 값을 이용하여 연산량을 줄였다. 또한, 추정된 움직임을 정규화하여 그 정확도를 더욱 향상시켰다. 실험 결과, 전체 탐색 블록 정합법과 POCS를 동시에 수행하여 영상을 재구성한 경우와 비교했을 때 유사한 화질의 HR 영상을 약 30배 빠르게 재구성하였다. In POCS (projection onto convex sets)-based reconstruction of HR (high resolution) image, the quality of reconstructed image is gradually improved through iterative motion estimation and image restoration. The amount of computation, however, increases because of the repeated inter-frame motion estimation. In this paper, an HR reconstruction algorithm is proposed where modified ARPS (adaptive rood pattern search) and POCS are simultaneously performed. In the modified ARPS, the motion estimates obtained from phase correlation or from the previous steps in POCS restoration are utilized as the initial reference in the motion estimation. Moreover, estimated motion is regularized with reference to the neighboring blocks' motion to enhance the reliability. Computer simulation results show that, when compared to conventional methods which are composed of full search block matching and POCS restoration, the proposed method is about 30 times faster and yet produces HR images of almost equal or better quality.

초등학생의 태권도 수련참여가 성취동기 및 학교생활 적응에 미치는 영향

임순길,송희근 龍仁大學校 體育科學硏究所 2005 體育科學硏究論叢 Vol.15 No.1

The purpose of this study is to determine the influence of Taekwondo training on elementary school students' motivation for accomplishment and adaptability to school life. For this purpose, this study involved male and female elementary school students aged from 11 to 13 taking Tae Kwon Do training in Kyunggi Do Province as of 2005, who are selected by the multi-stage stratified cluster random sampling. The number of people who were finally selected and used for the analysis was 391. The questionnaire entitled 「Influence of Taekwondo Training on Elementary School Students' Motivation for Accomplishment and Adaptability to School Life」 was used for the survey, whose reliability was verified through preliminary test. The coefficient of reliability was .705~.837, which is relatively good. We distributed reliable questionnaires during the preliminary research and collected them to analyze the result through various statistical methods including frequency analysis, t-test, one-way Anova, Scheffe's post-hoc test, correlation analysis and recurrent analysis. As a result of the analysis, we have drawn the following conclusion. First, in terms of motivation for accomplishment, there was a statistically meaningful difference of about 5% among dedication to the training. There was also a statistically meaningful difference of a 1% level in terms of adaptability to school life depending on the level of dedication to the training. Second, in terms of motivation for accomplishment, there was a statistically meaningful difference of about 1% depending on the length of training. There was also a statistically meaningful difference of about 1% in terms of adaptability to school life depending on the length of the training. Third, we examined the impact of dedication to training on motivation for accomplishment, and found that expectation for future has positive influence on the level of dedication, and self-confidence, interest level and expectation for future turned out to have positive impact on the length of the training. Forth, the level of dedication to the training have positive influence on student-teacher relationship and school discipline, while the length of the training turned out to have positive influence only on class lectures.

가우시안 채널에서 HC-CDMA 전송성능의 수학적 분석

김범곤(Bum-gon Kim),송희근(Hee-keun Song),김용철(Yong-cheol Kim) 한국통신학회 2006 한국통신학회 학술대회논문집 Vol.2006 No.11

제주도 밭의 외래잡초 분포

김창석,정영재,이인용,이정란,송희근,오영주 한국잔디학회 2015 Weed & Turfgrass Science Vol.4 No.3

제주도의 밭을 대상으로 141지점을 선정하여 조사를 진행하였다. 제주도 밭에 발생하는 외래잡초 조사결과 18과50속 64종 2변종, 총 66분류군의 외래잡초가 조사되었고 동계작물 재배지에서는 18과 45종, 하계작물 재배지에서는16과 50종, 다년생 작물 재배지에서는 17과 39종이 출현하였다. 외래잡초의 생활형은 하계일년생 잡초가 39.4%, 동계일년생은 잡초는 36.4%, 하계일년생과 동계일년생이 모두 가능한 잡초는 7.6%, 다년생 잡초는 16.7%로 분석되었다. 특히 하계작물 재배지에서 하계일년생 잡초의 비율이 높았다. 종의 과별 분포순위는 국화과, 벼과, 아욱과가우점하는 것으로 분석되었으나 다년생 작물 재배지에서는아욱과는 출현하지 않았다. 제주도의 동계작물 재배지에서우점하는 외래잡초는 흰명아주, 청비름, 개쑥갓, 냄새냉이, 들개미자리였고 하계작물 재배지에서는 흰명아주, 청비름, 개쑥갓, 방가지똥이었다. 다년생 작물 재배지에서는 큰망초, 선풀솜나물, 개쑥갓, 흰명아주로 조사되어 다른 작물과차이를 보였다. 제주도 전체 밭에서 발생하는 외래잡초의우점종은 흰명아주, 청비름, 개쑥갓, 큰망초, 방가지똥 등으로 분석되었다. 제주도에 발생하는 외래잡초의 발생정보는밭의 지속적인 관리방안을 수립하는데 도움이 될 것이다. We surveyed the distribution of exotic weeds in the 141 crop fields of Jeju island. The exotic weeds were summarized as 66 taxa including 18 families, 50 genera, 64 species and 2 varieties. In winter crop fields there were 45 species of exotic seeds in 18 families, in summer crop fields 50 species in 16 families, and in perennial crop fields 39 species in 17 families. Total exotic weeds were classified to 39.4% of summer annuals, 36.4% of winter annuals, 7.6% of summer and winter annuals, and 16.7% of perennials. The ratio of summer annuals were high in the summer crop fields. Compositae was dominant family, followed by Gramineae, Malvaceae and Solanaceae. Malvaceae did not appear in perennial crop fields. Dominant exotic weeds in winter crop fields were Chenopodium album, Amaranthus viridis, Senecio vulgaris and Coronopus didymus, in summer crop fields, Chenopodium album, Amaranthus viridis, Senecio vulgaris and Sonchus oleraceus and in perennial crop fields, Conyza sumatrensis, Gnaphalium calviceps and Senecio vulgaris. The dominant exotic weeds in the crop fields of Jeju island were Chenopodium album, followed by Amaranthus viridis, Senecio vulgaris, and Conyza sumatrensis. This information could be useful for establishment of exotic weed control methods in Jeju island.

곰취밭에 발생하는 잡초양상

이인용,김창석,이정란,김종환,김경훈,김미선,송희근,김덕환 한국잔디학회 2014 Weed & Turfgrass Science Vol.3 No.2

This study was conducted in order to utilize the basic data for weed control by surveying the occurrence of weedspecies and the degree of damages caused by those weeds occurred in cultivated Ligularia fischeri fields. Survey was carried outfive times, on May, June, July, August and October in 2013. The weed flora was composed of a total of 104 weeds, 37 families, ofwhich 55 species were annual, 25 species were biennial, and 24 were perennial plants. Twenty-six exotic species were included aswell. Dominance was the highest with Chenopodium album followed by Stellaria aquatica, Echiochloa crus-galli, Conyzacanadensis, and Artemisia princeps etc. in order. In the PCA plot analysis, weeds occurred in cultivated L. fischeri fields weredivided into three groups, Persicaria thunbergii-Bidens frondosa community, Chenopodium album community and Capsella bursapastoriscommunity. The degree of damages in cultivated L. fischeri fields was investigated by weighing roots of L. fischeri. We found that 56% decreased root weight in no weeding plots comparing to that in weed management plots. We infer from thisresult that decreased roots will affect to the growing of L. fischeri in following year. 곰취밭에 발생하는 잡초발생 양상과 잡초로 인한 피해정도를 파악하여 곰취밭 잡초방제의 기초자료로 활용하기위하여 2013년 5월부터 10월까지 5회 조사하였다. 곰취밭에 발생하는 잡초는 37과 104종으로 일년생잡초가 55종,월년생잡초 25종 그리고 다년생잡초가 24종이었다. 이 중에서 외래잡초는 26종이 발생하였다. 우점도가 높은 잡초로는 명아주, 쇠별꽃, 돌피, 망초, 쑥 등이었으며, OrdinationPCA 분석한 결과, 고마리-미국가막사리 군락, 명아주 군락 그리고 냉이 군락으로 분석되었다. 잡초에 의한 곰취의 피해 정도를 곰취 뿌리 무게로 비교한 결과, 잡초관리구에 비교하여 잡초방임구가 56% 작아져서 이듬해 곰취생육에 영향을 줄 것으로 판단된다.

제주지역 목초지에 발생하는 잡초양상

이인용,김창석,이정란,황경준,김경훈,김미선,송희근 한국잔디학회 2015 Weed & Turfgrass Science Vol.4 No.1

This study was conducted to investigate the occurrence of weed flora in pastures in Jeju island of Korea and toestablish the basic data for controlling them occurred in the pastures. Weed flora was investigated twice, May and July on 2003. There were a total of 207 weed species including 49 families. Among them 67 species were annual, 39 species were biennial and101 species were perennial. The compositions of major plant families, Asteraceae, Poaceae, Polygonaceae, Rosaceae, Fabaceae were17, 15, 8, 7, 6%, respectively. Sixty-eight species of exotics were occurred, as well. Rumex obtusifolius was the highest in importanceanalysis and the followings were in order of Trifolium repens, Artemisia princeps, Plantago asiatica, Potentilla anemonefolia andRumex acetosella etc. Among the exotic weeds, R. obtusifolius, T. repens, R. acetosella and C. holosteoides var. hallaisanense might bemost problematic weeds species in pastures in Jeju island in the future. And at the boundary of some pastures and mountainsSmilax china, Duchesnea indica, Rosa maximowicziana, etc. 17 shrub species were also occurred. 제주도 목초지에 발생하는 잡초를 조사하여 목초지 문제잡초의 현황을 파악하고 잡초방제의 기초자료로 활용하기위하여 2013년 5월과 7월에 2회 실시하였다. 제주지역 목초지에 발생하는 잡초는 49과 207초종으로 일년생잡초가전체의 32%를 차지하는 67종, 월년생잡초가 19%로 39종,그리고 다년생잡초가 49%로 101종이었다. 그리고 과별로보면, 국화과 17%, 화본과 15%, 마디풀과 8%, 장미과 7%,콩과 6%, 석죽과, 십자화과, 꿀풀과 각각 3%순으로 발생하였다. 우점도가 높은 잡초로는 돌소리쟁이, 토끼풀, 쑥, 질경이, 가락지나물, 애기수영 등의 순이었다. 외래잡초는 22과 68초종으로 전체 32.9%를 차지하였으며, 이 중에서 돌소리쟁이, 토끼풀, 애기수영, 점나도나물 등은 향후 제주도목초지에서 문제가 될 것으로 판단된다. 일부 목초지와 산지와의 경계부분에서 청미래덩굴, 뱀딸기, 용가시 등의 목본식물도 발생하였다.

경기도 외래잡초 분포 특성

김창석(C. S. Kim),이인용(I. Y. Lee),이정란(J. Lee),송희근(H. G. Song),오영주(Y. J. Oh),이욱재(W. J. Lee) 한국잡초학회 2014 한국잡초학회 별책(학술대회 초록집) Vol.34 No.2

SPCPC에서 LDPC부호를 이용한 오류 정정

김성만(Sungman Kim),오태석(Taesuk Oh),김범곤(Bum Gon Kim),송희근(Hee Keun Song),김용철(Yong Cheol Kim) 한국방송·미디어공학회 2006 한국방송공학회 학술발표대회 논문집 Vol.2006 No.-

본 논문은 AWGN 채널상의 Single Parity Check(SPC) 다차원 product부호에서 LDPC(Low Density Parity Check)부호를 이용한 오류 정정의 성능을 제시한다. 기존 방법인 터보 부호 방식을 이용한 오류 정정과 비교하여 LDPC부호가 갖는 장점을 기술하고 실험을 통해 LDPC 부호를 이용한 오류 정정 성능도 터보부호와 대등함을 보인다.