페이딩 채널환경에서 CDFDM 시스템에 대한 채널 추정과 결합된 심볼검출 방법

조진웅,강철호,Cho, Jin-Woong,Kang, Cheol-Ho The Institute of Electronics and Information Engin 2000 電子工學會論文誌-TC (Telecommunications) Vol.37 No.9

본 논문에서는 페이딩 채널환경에서 COFDM 시스템에 대한 채널 추정과 결합된 심볼 검출 방법에 대해 제안하였다. 제안된 방법은 1) 심볼의 길이에 채널 부호화기의 코드워드 길이를 배합하는 기법과, 2) 세가지 채널 추정 기법과의 조합으로 나타내었다. 첫째 방법은 훈련 신호를 이용한 채널추정 기법과 제안한 심볼 검출 기법을 결합시킨 것이며, 둘째 방법은 첫째 방법에 결정지향 채널추정(Decision-Directed Channel Estimation) 기법을 결합시킨 방법이다. 마지막으로, 근접 부채널간의 AWGN(Additive White Gaussian Noise)의 영향을 줄이기 위해 디인터리브된 평균 채널추정(Averaged Channel Estimation) 기법을 둘째 방법에 결합시켰다. 제안한 3가지 방법들은 영 강압 등화(Zero Forcing Equalizing)방법과 비교하여 커다란 성능 개선 효과가 있음을 컴퓨터 시뮬레이션을 통하여 검증하였다. This paper proposes symbol decoding schemes combined with channel estimation techniques for coded orthogonal frequency division multiplexing (COFDM) systems in fading channels. sThe proposed symbol decoding schemes are consisted of a symbol decoding technique and channel estimation techniques. The symbol decoding based on Viterbi algorithm is achieved by matching the length of branch word from encoder trellis to the codeword length of symbol candidate on decoder trellis. Three combination schemes are described and their error performances are compared. The first scheme is to combine a symbol decoding technique with a training channel estimation technique. The second scheme joins a decision directed channel estimation technique to the first scheme. The time varying channel transfer functions are tracked by the decision directed channel estimation technique and the channel transfer functions used in the symbol decoder are updated every COFDM symbol. Finally, In order to reduce the effect of additive white Gaussian noise (AWGN) between adjacent subchannels, deinterleaved average channel estimation technique is combined. The error performances of the three schemes are significantly improved being compared with that of zero forcing equalizing schemes.

페이딩 채널환경에서 OFDM 시스템에 대한 심볼 검출 및 채널 추정 기법

조진웅,강철호,Cho, Jin-Woong,Kang, Cheol-Ho 대한전자공학회 2001 電子工學會論文誌-TC (Telecommunications) Vol.38 No.3

본 논문에서는 페이딩 채널 환경에서 OFDM 시스템의 채널추정과 심볼 검출이 결합된 방식들을 제안하였다. 제안된 방식들은 결정지향 채널 추정(DDCE) 방식에 근거하여 채널을 추정하며 비터비 알고리즘을 이용한 심볼 검출을 수행한다. 제안된 비터비 결정지향 추정 (VDDCE)방식은 시간상 변화하는 채널을 추척하고 ML 심볼 열을 검출 한다. VDDCE방식에 근거한 순환적 비터비 결정지향(RVDDCE) 방식에서는 복잡도를 줄이기 위해 검출될 심볼 열의 길이를 줄인다. 즉, 훈련 심볼의 간격동안에 채널 추정과 비터비 알고리즘이 일정 간격으로 반복적으로 수행되도록 한다. 또한,AWGN의 효과를 줄이기 위해 평균화 채널 추정(ACE) 방식을 VDDCE와 RVDDCE 방식에 적용하였다. 제안된 방식들은 컴퓨터 시뮬레이션으로 검증하였다. In this paper, we present the joint symbol detection and channel estimation for an orthogonal frequency division multiplexing (OFDM) system in fading channels. The proposed methods are based on decision-directed channel estimation (DDCE) method and their symbol detection is achieved by using Viterbi algorithm. This Viterbi decision-directed channel estimation (VDDCE) method tracks time-varying channels and detects a maximum likelihood symbol sequence. Recursive Viterbi decision-directed channel estimation (RVDDCE) method based on VDDCE method is proposed to shorten the detecting depth. In this method, channel estimate and Viterbi processing are recursively performed every interval of training symbol. Also, average chann'el estimation (ACE) technique to reduce the effect of additive white Gaussian noise (AWGN) is applied VDDCE method and RVDDCE method. These proposed methods arc demonstrated by computer simulation.

NaCl stress 에 의한 몇가지 보리 품종들의 생육시기별 생육 특성

조진웅(Jin Woong Cho),박기선(Ki Sun Park),이석영(Sok Young Lee) 한국환경농학회 2000 한국환경농학회지 Vol.19 No.1

This study was conducted to investigate the growth characteristics of four barley cultivars to NaCl stress of 100mM on 10 March (Tillering stage) and 10 April(Panicle formation stage). Plant grown in Wagner pot(1/5,000 a) with sand culture. Plant height, root length, leaf number and tillering number reduced by NaCl stress and tillering number was shorter than any other character. The reduction of those with NaCl treatment was more severe in 10 March treatment compared to in 10 April it. Leaf, root and straw weight were decreased with NaCl treatment and root weight was more sensitive than any others on 10 March and 10 April treatment. One hundred grain weight (g) in grain component was the most severe in 10 March treatment and panicle number per plant was the most severe in 10 April treatment. The result also varied depending on the cultivars and the time of NaCl stress. In terms of yield component, salt sensitivity was low in order of Bunong, Chalssalbori, Dongbori 1, and Neulssalbori in 10 March and Neulssalbori, Dongbori 1, Bunong and Chalssalbori in 10 April treatment by 100mM NaCl.

외국인 투자자의 포트폴리오 성과분석

조진웅(Cho, Jin Woong),홍순정(Hong, Soon Jung) 한국국제회계학회 2012 국제회계연구 Vol.0 No.46

우리나라 주식시장은 외국인 투자자 지분율이 높아 주식시장에 미치는 영향력이 매우 크다. 일반적으로 외국인 투자자의 주식 투자는 기업지배구조를 개선함과 동시에 경영의 투명성을 제고하는 긍정적인 영향과 과도한 배당을 요구하거나 단기적 이익만을 추구하는 부정적인 영향을 미친다는 상반된 논란이 끊임없이 제기되어 왔다. 본 연구는 우리나라 주식시장에 상장되어 있는 12월 결산법인 주가자료를 이용하여 외국인 투자자의 투자행태와 포트폴리오성과를 분석하였다. 분석방법은 외국인 투자자의 지분율을 이용하여 포트폴리오를 구성한 후 2001년 1월부터 2007년 12월까지 월별수익률을 Fama and French three-factor model을 이용하여 분석하였다. 주요 분석결과는 다음과 같이 정리할 수 있다. 첫째, 외국인 투자자의 투자행태를 살펴보면 외국인 투자자는 기업규모가 크고 안정적인 성장을 지속하며, 수익률 변동성이 적은 기업을 중점적으로 투자하며, 투자기간 또한 단기 투자가 아닌 장기간에 걸쳐 투자하는 투자행태를 보인다고 할 수 있다. 둘째, 위험요인이 통제된 Fama and French three-factor model을 사용하여 포트폴리오성과를 분석하였다. 분석결과 투자성과는 2.375%로 유의적인 값을 가지는 것으로 나타났다. 외국인 투자의 투자행태를 살펴보면, 기업규모와 관련해서는 유의적인 부(-)의 관계가 나타났고 장부가치/시장가치 비율인 가치 측면에서는 유의한 정(+)의 관계를 가지는 것으로 나타났다. The objective of this paper is to analyze the performance of portfolio by foreign investors in Korean stock market. Since the foreign investors have been allowed to invest freely in the Korean stock market from 1998, the foreign investors’ trading behavior has had allegedly positive or sometimes negative effect on domestic investors trading behavior, especially on that of the individual investors. I have identified the characteristic of foreign investors preferred holding stocks using the annual financial data and the related stock market data during the term of seven years between 2001 and 2007. The result shows that, as expected in the previous literatures, foreign investors tend to hold large size stocks. This implies that foreign investors trading behavior has different market impact on the return and the volatility depending on the size of the firm. Moreover, this study confirms that the market volatility could be decreased by the foreign investors trading behavior as argued in the previous literatures. Important empirical results are summarized as follows: (1) The foreign investors have features like large business scale, stable and continuous development, and long-term investment to high earning rate business. (2) On the basis of "Fama and French three-factor model", we have analyzed the result of this portfolio without risk factors. As a result, It has proved that get a significantly performance with 2.375%. In case of foreign investors, B/M ratio is significantly positive to them. However, it proves that has significantly negative to them in firm size.

몇가지 禾本科牧草와 콩科牧草를 混播할 경우 播種比率에 따른 牧草의 生産性과 競合關係

趙振雄(Jin Woong Cho),金忠洙(Choong Soo Kim),李錫榮(Suk Young Lee) 충남대학교 농업과학연구소 1993 Korean Journal of Agricultural Science Vol.20 No.2

자동차보험료 자율화와 손해보험사의 장기성과

조진웅(Cho, Jin-Woong) 대한경영학회 2009 大韓經營學會誌 Vol.22 No.1

전기적 열분해를 이용한 탄소/망간산화물 복합 구조체 슈퍼캐퍼시터 전극 개발

조진웅(Jin Woong Cho),여태한,신동준,최원준 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.12

파종기별 논콩재배의 수량 및 생태적 특성

조진웅(Jin-Woong Cho),이석영(Sok-Young Lee),강순경(Soon-Kyung Kang),김충수(Choong?Soo Kim) 충남대학교 농업과학연구소 2006 Korean Journal of Agricultural Science Vol.33 No.2

본 시험은 논에서 콩을 재배할 경우 파종기 및 재식밀도를 달리할 경우 수량과 생육에 미치는 영향을 알고자 실시하였으며 그 결과는 다음과 같다. 1. 파종기에 따른 수량은 5월 단작이 가장 많았으며, 7월 5일 파종할 경우 가장 적었는데, 풍산나물콩 5월 24일 파종은 10a 당 362 ㎏을 보였다. 백립중은 풍산나물콩의 경우 파종이 늦을수록 증가하였으나 한남콩은 감소하는 경향을 보였다. 2. 경장, 엽면적, 건물중은 5.24 파종이 가장 높았으며, 6.14 파종과 7.05 파종은 큰 차이를 보이지 않았다. 3. 개화기 및 착협기의 엽 건물중과 수량간에는 높은 정의 상관을 보였으나 입비대시는 유의성은 없었으며, 파종기에 따른 상대생장율(RGR)은 파종기가 늦을수록 증가하였다. 4. 파종기에 따른 광합성은 정엽의 경우 큰 차이를 보이지 않았지만, 입비대시의 제 7엽의 광합성은 5월 24일 파종때보다 6.14와 7.05 파종에서 보다 높은 경향을 보였다. This study was conducted on a commerce silt loam soil at paddy field in the southwestern Korea (36° N lat). In the study of planting time, seed were hand planted at 24 May, 14 June and 5 July, and at 24 May, 14 June and 5 July in 2005, respectively. Two seedlings plants per hill were taken prior to V3 stage. Fertilizer was applied prior to plant at a rate of 3.0 - 3.0 - 3.4 g (N - P - K) per square meter. Experimental design was a randomized complete block in a split plot arrangement with three replications. Yield was significantly affected by different of the planting times and cultivars. The seed yield in planting time was the highest on late in May 24 but was the lowest on July 5. Also, the plant time significantly affected on increasing pod and seed number and seed weight. The days from emergence to flowering and maturity was reducing tendency with late planting time. The highest and lowest total dry matter production per square meter appeared at late in May and early in July with planting time, respectively. RGR, LAR and SLA was increased with late planting time. Photosynthetic rate at each planting time was not significant on the expanded the highest leaf position but at seed development stage, it was higher photosynthetic rate at May 24 than that of late planting time on 7<SUP>th</SUP> laef position from the basal part.

NaCl stress 에 의한 몇가지 콩 품종들의 생육과 광합성 반응

조진웅(Jin Woong Cho),김충수(Choong Soo Kim) 한국환경농학회 2000 한국환경농학회지 Vol.19 No.2

This study was conducted in to elucidate the changes of growth characteristics and photosynthesis in three soybean (Glycine max L. cv. Danwonkong, Hwangkeumkong and Kwangankong) 30 day old seedlings to 100mM NaCl concentration containing ½ Hoagland`s nutrient solution in sand culture. The main stem height and number of main stem node were decreased. thus, leaf area and dry matter were decreased with 100mM NaCl. Growth reduction was less little in Hwangkeumkong than other cultivars. The stem growth rate was affected less than other parts as root or leaf, by NaCl treatment. The specific leaf area (SLA), shoot : root ratio and leaf : root ratio decreased with NaCl solution except for those of Hwangkeumkong. There is no general tendency in leaf thickness by leaf position of three cultivars. The chlorophyll content (SPAD) of the primary and 2nd leaf slightly decreased under NaCl solution but rapidly increased in non-NaCl solution at 15 days after treatments. The photosynthesis, stomatal conductance and transpiration of 2nd leaf positions reduced by NaCl and there were a sigificant correlation between photosynthesis and stomatal conductance or transpiration.

NaCl Stress 에 따른 보리 유묘의 생육특성 및 세포학적 반응

조진웅(Jin Woong Cho),김충수(Choong Soo Kim),이석영(Sok Young Lee),박기선(Ki Sun Park) 한국환경농학회 1998 한국환경농학회지 Vol.17 No.4

This study was conducted to determine the morphological responses of barley seedlings to NaCl stress and to investigate histological changes of cells with transmission electron microscope(TEM) after NaCl stress. Plant height and root length of 10-day old barley seedlings with NaCl stress were reduced and inhibition level was found to be more severe in the plant height than in the root length. The leaf length, leaf width and leaf area were shorter as well with NaCl stress than without NaCl stress. However, there was no difference in the number of roots between NaCl treatments. The weight of dry matter decreased at higher NaCl concentrations, especially at 100mM NaCl. The water content of shoots tend to decrease at higher NaCl concentrations, but there was no difference in the water content of roots, The reduced sugar content was greatly increase than starch. Cellulose content was higher in NaCl stressed-plant than control, and tended to decreased at higher NaCl concentrations. Lignin content also decreased NaCl stressed-plant but there was no tendency at NaCl stress concentrations. Electric conductivity of cell sap with seedlings was high with NaCl stressed-plant. Amount of cell sap gradually increased with time in the roots than in the shoots, The grana of chloroplasts was changed by 150mM NaCl concentration. The christe of mitochondria in root meristematic sells ruined in structure and cell wall of leaf and root was also ruined by NaCl stress.