• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1998년도 가을 학술발표논문집 Vol.25 No.2 (3)
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• pp.624-626
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• 1998

In this paper. a new simple and efficient technique to improve the convergence speed of LMS algorithm is introduced. The convergence characteristics of the proposed algorithm, whose coefficients are multiply adapted in a symbol time period by recycling the received data, are analysis to prove theoretically the improvement of convergence speed. The theoretical analysis shows that the data-recycling LMS technique can increase convergence speed by (B+1) times, where B is the number of recycled data. The results of the computer simulation demonstrate that the simulation results are in accordance with the theoretical analysis and the superiority of the filter algorithm

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.265-268
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• 2004

In this paper. we propose an adaptive step-size algorithm for the adaptive interference canceller (AIC) in the space-time trellis coded DS-CDMA system. In the AIC, the performance of the blind LMS algorithms that updates the tap-weight vector of the AIC is heavily dependent on the choice of step-size. To improve the performance of the fixed step-size AIC (FS-AIC), the regular adaptive step-size algorithm is extended in complex domain and applied to the joint AIC and ML decoder scheme. Simulation results show that the joint adaptive step-size AIC (AS-AIC) and ML decoder scheme using the proposed algorithm has boner performance than not only the conventional ML decoder but also the joint FS-AIC and ML decoder scheme without much increase of the decoding delay and complexity.

• 수산해양교육연구
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• 제15권1호
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• pp.115-122
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• 2003

Generally, material for radiator of automobile is composed of Al-alloy, but part of radiator material is still composed of Cu. Specially, Al-alloy replaces Cu and Cu-alloy as cooling and heating system material for light weight. Therefore, galvanic electronic cell is formed between Al-alloy and Cu for automobile radiator material, and Al-alloy corrosion is accelerated. So, in this study, galvanic corrosion test of Al-alloy coupling with Cu was carried out in distilled water, tap water, polluted environment and non-freezing solution. And thus corrosion potential and galvanic currrent density of Al-alloy coupling with Cu is investigated.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.712-716
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• 2003

본 논문은 신경망을 이용한 간섭 신호 제어로써 복합 다중 퍼셉트론에서 DS/SS 이동 통신에서의 수신된 신호들을 역전파 학습알고리즘을 이용하여 검출하는 것에 대하여 연구한다. 수신 신호가 일정한 비트율을 갖는 채널에 전송하기 위하여 신경망을 이용한 새로운 탭 가중치 갱신 제어 방법을 제안한다. 적응 횡단선 필터는 심볼간의 채널에 발생하는 상호 심볼간 간섭을 억압하기 위해 LMS 알고리즘 사용한다. 이 알고리즘은 원하는 응답과 실제 출력간의 차인 에러를 이용하여 탭 가중치 조절 메카니즘을 통해 탭 가중치를 갱신함으로서 효과적으로 간섭을 제거하였다. 본 논문은 상호 심볼간 간섭을 효율적으로 억압해온 기존의 LMS 알고리즘에 다계층 퍼셉트론 신경망을 조합한 새로운 BISP 알고리즘을 제안하였으며, 제안된 알고리즘을 통해 탭 가중치 갱신이 보다 효율적으로 이루어짐을 알 수 있다. 시뮬레이션 결과를 통해 제안된 알고리즘의 평균 자승 에러의 수렴 특성이 기존 LMS 알고리즘을 이용한 수렴특성보다 우월하다는 것을 나타내었다.

• 한국통신학회논문지
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• 제34권5C호
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• pp.521-526
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• 2009

In this paper, a complex-valued recursive least squares escalator filter algorithm with reduced computational complexity for complex-valued signal processing applications is presented. The local tap weight of RLS-ESC algorithm is updated by incrementing its old value by an amount equal to the local estimation error times the local gain scalar, and for the gain scalar, the local input autocorrelation is calculated at the previous time. By deriving a new gain scalar that can be calculated by using the current local input autocorrelation, reduced computational complexity is accomplished. Compared with the computational complexity of the complex-valued version of RLS-ESC algorithm, the computational complexity of the proposed method can be reduced by 50% without performance degradation. The reduced computational complexity of the proposed algorithm is even less than that of the LMS-ESC. Simulation results for complex channel equalization in 64QAM modulation schemes demonstrate that the proposed algorithm has superior convergence and constellation performance.

• 한국통신학회논문지
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• 제25권6B호
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• pp.1074-1081
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• 2000

In this paper, in order to speed up the convergence process and improve the steady mean square error simultaneously, we propose the Stop-and-Go Dual Mode Modified Constant Modulus Algorithm(SAG DM MCMA) for adaptive blind channel equalization of high order QAM. The proposed algorithm is a hybrid scheme of the Modified CMA that treat error signals with real and imaginary components of the equalizer output, the concept of dual mode CMA, and Stop-and-Go algorithm. As a result it can prevent blind equalization from converging to incorrect direction and simultaneously operates reliably for tap weight adaptation. We demonstrate via simulation that the proposed algorithm achieves lower steady state mean square error and residual ISI than the conventional algorithms under high order QAM signals and severe channel environment.

• 생물환경조절학회지
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• 제18권4호
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• pp.460-467
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• 2009

본 연구는 실내에 식물을 보다 효율적으로 도입하고자 수경재배 시 첨가매질(게르마늄, 맥반석)이 관엽식물의 생장과 잎의 무기성분, 뿌리활력에 미치는 영향을 구명하기 위하여 수행되었다. 싱고니움(Syngonium podophyllum), 드라세나 산데리아나(Dracaena sanderiana), 스킨답서스(Epipremnum aureum) 및 아이비(Hedera helix)를 식물재료로 사용하였으며 토양(혼합된 상토: Sunshine Mix No. 2, USA), 수돗물, 수돗물에 게르마늄(300g), 수돗물에 맥반석(300g)을 첨가하여 정식하였다. 첨가매질에 따른 생육변화는 싱고니움의 경우 수돗물만 처리한 구에서 가장 저조하였고 게르마늄 첨가구에서 생육이 가장 좋았으며, 드라세나 산데리아나는 처리구에 따른 생장의 차이가 거의 없는 반면, 스킨답서스와 아이비의 생장도 게르마늄 첨가구에서 가장 좋았다. 특히 뿌리의 생장에서 커다란 차이를 보였는데 근장, 근수 및 근중이 게르마늄 첨가구에서 가장 좋았다. 뿌리활력은 10일 간격으로 분석하였는데 작물마다 처리구에 따라서 변화가 있었는데 싱고니움의 경우 10일째는 3처리구 다 뿌리활력이 낮아졌으나 차츰 좋아져 30일과 50일째에는 맥반석 첨가구에서 가장 좋았다. 드라세나의 경우 10일째부터 40일째까지 게르마늄 첨가구에서 가장 좋았으나 50일째부터 뿌리활력이 나빠졌다. 그러나 60일 후에는 처리구간 큰 차이가 없었다. 식물체 잎의 무기성분 분석 결과, 게르마늄의 Ca과 Mg 함량이 맥반석 보다 높았지만 잎의 무기성분 함량에는 영향을 미치지 않는 것으로 나타났다. 이상의 결과에서 스킨답서스와 아이비는 배지재배보다 수경재배에서 생장이 좋았고, 수경재배시 수돗물에 게르마늄을 첨가하였을 때 생육이 증가하는 것으로 나타났다.

• 한국정보통신학회논문지
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• 제7권4호
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• pp.691-698
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• 2003

적응 횡단선 필터에서 수렴 속도의 개선을 위해 기존의 최소 평균 자승 알고리즘을 확장한 반복적 최소 자승 알고리즘의 탭 가중치 갱신 메커니즘에 재순환 데이터 버퍼를 이용함으로서 수렴특성을 개선시키는 효율적인 기법을 제시하였다. 본 논문은 기존의 적응 횡단선 필터에 데이터 재순환 버퍼 구조를 제안하여 새로운 RLS 탭 가중치 갱신 알고리즘을 유도하여 조화 평균 학습 곡선의 평균 자승 에러 값에 대한 반복수에 대해서 데이터 재순환 버퍼를 사용한 학습 곡선의 수렴 속도가 버퍼가 없는 경우의 재순환 버퍼 RLS 알고리즘의 수렴 속도보다 비례하여 빠르게 수렴한다는 것을 수학적인 연산을 통해 증명하였다. 채널 진폭의 왜곡의 정도와 재순환 데이터 버퍼 수에 따른 평균 자승 에러에 대한 삼차원 시뮬레이션 결과로부터 고유치 확산이 증가함에 따라 특정 값에 수렴하기 위한 요구된 샘플의 반복수가 비례하여 증가하였으며, 재순환 데이터 버퍼 수 B가 증가함에 따라 요구된 샘플의 반복수가 B배만큼 감소함으로서 제안된 구조에서 RLS 가중치 갱신 알고리즘의 수렴특성이 개선됨을 입증하였다.

• 한국가정과학회지
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• 제6권1호
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• pp.27-34
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• 2003

We investigated the bacterial and chemical retting conditions of ramie grown in Hansan. Bacterial retting was done in troughs at a temperature of 30${\pm}$2$^{\circ}C$ for 1, 2, 3, 4, 5, 6 and 10 days. Chemical retting(CR) was done at the different conditions using sodium silicate (Na$_2$SiO$_3$), sodium carbonate(Na$_2$CO$_3$) and sodium hydroxide(NaOH) as alkali solutions. The retting solution was boiled during 1. 2, 4 and 6 hours respectively at the different concentration(0.5, 2.0, 4.0, 6.0. 8.0 %) with decorticated ramie stems submerged in it. The treated ramie was then rinsing with running tap water thoroughly, which was further soaker in 0.5% acetic acid (v/v) solution for three minutes and washed thoroughly with distilled water. Finally ramie was dried for 2 hours in vacuum oven at 100 $^{\circ}C$. To know change of ramie fiber characteristics retted at the different conditions, weight loss, fiber bundle strength were tested and color, texture, luster etc. were also sensually evaluated. The results were as follows. $.$ Weight loss of ramie retted in each alkali solutions were about 10%, 20% and 30% in sodium silicate, sodium carbonate and sodium hydroxide, respectively. $.$ Chemical retting was faster than bacterial retting, but the color of chemically retted ramies were worse than that of bacterially retted ramies. $.$ The combination of bacterial and chemical processing showed some merits. A combination of either 2 or 3 days of bacterial and then chemical retting might provide the best quality ramie. $.$ Ramie fiber became cottonized ramie when retted in 8% NaOH solution for 6-8hours.

• 한국작물학회지
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• 제44권4호
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• pp.373-381
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• 1999

Six soybean cultivars having different SDS susceptibility were planted with sorghum seedinoculum infested with F. solani isolate 171 in the greenhouse. First leaf symptoms appeared on unifoliar leaves at 9 days after inoculation and all cultivars showed the typical leaf symptoms at 13 days after inoculation, when trifoliar leaves emerged. Leaf symptoms development in susceptible cultivars was faster than in resistant cultivars. Leaf symptom severities during the period of 25 to 29 days after inoculation showed a significant difference between cultivars which had SDS resistance and sus ceptibility. In this period, area under the diseaseprogress curve (AUDPC) of Hartz 6686 was the highest and that of PI 520733 was the lowest. SDS caused serious damage to the growth of soybean in all cultivars. Average reductions of growth rate of root fresh weight and dry weight were greater than those of plant tops. Duyu-kong showed less severe leaf symptoms than that of SDS suscetible cultivars; however, average growth rate of plants top and roots of this cultivar was less but not significantly different than those of SDS susceptible cultivars. In all cultivars, as severity of leaf symptoms increased, plant top weight decreased. Root rot symptoms were observed in all cultivars before leaf symptoms appeared. Average proportions of tap root reddish-brown discoloration of all cultivars was up to 75 % at 15 days after inoculati on; however there was no significant differenc between cultivars at each rating date. Appearances of leaf symptoms on leaves varied in each cultivar. SDS resistant cultivars had a significantly higher level of crinkling than susceptible cultivars and SDS susceptible cultivars had a significantly higher level of necrosis than resistant cultivars. Further study will be needed to identify the relationships between the physiological growth rate and SDS severities in soybeans.