• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2200-2203
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• 2003

In an active noise control(ANC) system using the Filtered-X least mean square(LMS) algorithm, the online secondary path modeling method by exploiting a random noise generator is applied. This method is suitable for secondary path modeling. However, it is increased the residual error of the ANC system. In this paper, we presents an ANC system improved online secondary path modeling method which is modified Kuo and Zhang model that is the secondary path estimation by the additive noise. In addition, our proposed model is used that additive noise is transformed into the signal multiplied reference signal by gain control parameter and delayed.

• 한국통신학회논문지
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• 제22권7호
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• pp.1590-1598
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• 1997

The paper first introduces the new concept of potential diversity and signal decomposability, which establish a foundaton to generalize the existing concepts of path and frequency diversities. Then it presents a new DS/CDMA system called chip-spreading OCDM system, which is an embodiment of the petential diversity concept that combines the path diversity of the DS/CDMA system and the frequency diversity of the OFDM/CDMA system. In the chip-spreading OCDM system the chip sequences in each symbol interval are first converted into aralled streams, which then simultaneously modulate different orthogonal Walsh basis functions. In the receiver, the received signal is matched to each extended basis-function which is the union of the transmitter basis-functions and their delayed replicas, and the matched-filtered chip samples are combined together after individual channel compensation. The conventional DS/CDMA system using the maximal ratio combining. In addition, it effectively resolves the high PAR and high sensitivity to frequency offset problems which are critical in multi-carrier systems.

• 융합신호처리학회논문지
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• 제3권4호
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• pp.62-66
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• 2002

SOCMAC 신경망에 의하여 Mackey-Glass의 비선형 시계열 예측을 시도하였다 다차원 연속 입력 변수를 가지는 문제는 요구되는 기억용량의 규모가 너무 커서 CMAC에서는 일반적으로 취급이 곤난한 대상이었으나 SOCMAC에서는 이것이 가능함을 보였다. 또한 학습과정에서 수용영역(receptive field)을 가변으로 하는 개선된 방법을 제시하였다. 예측오차는 TDNN(time-delayed neural network)이나 BP(back-propagation) 수준이었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.49-51
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• 1996

The z-transform method is a basic mathematical tool in analyzing and designing sampled-data control systems. However, since the z-transform method relates only the sampling-instants signals, another mathematical tool is necessary to describe the continous signals between the sampling instants. For this purpose the delayed and the modi fled z-transform methods were developed. The definition of the modi fled z-transform includes a sample in the interval [-T,0] of the original signal in its series expression, where the signal value is always zero for any physical system. From this reason one step skew of the time index always appears in its application formulas. This introduces an unnecessary operation and a gap in linking the mathematical formula and its physical interpretation. Considering the conceptual difficulty and application inconvenience, a method of using the advanced z-transform in analysis of sampled-data control systems is developed as a replacement of the modi fled z-transform. With one formulation of the advanced z-transform, now it is possible to relate both the signals of the sampling instants and those in between without any complication and conceptual difficulty.

• 대한원격탐사학회지
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• 제26권6호
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• pp.645-652
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• 2010

The performance of the payload Electro-Optical System (EOS) in satellite system is affected by various factors, such as optics design, camera electronics design, and the characteristics of the CCD (Charge Coupled Device) used, etc. Of these factors, the camera electronics design is somewhat unique in that its operational parameters can be adjusted even after the satellite launch. In this paper, the effect of video gain on the non-uniformity correction performance is addressed. And a new optimal non-uniformity correction scheme is proposed and analyzed using the data from real camera electronics unit based on a TDI (Time Delayed Integration) type of CCD. The test results show that the performance of the conventional non-uniformity correction scheme is affected significantly when the video gain is added. On the other hand, in our proposed scheme, the performance is not dependent on the video gain. The insensitivity of the non-uniformity performance on the video-gain is mainly due to the fact that the correction is performed after the dark signal is subtracted from system response.

• 한국통신학회논문지
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• 제26권11A호
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• pp.1820-1826
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• 2001

본 논문에서는, 건물 내에 이미 포설되어 있는 2선식 전화선을 이용하여 데이터 망을 구축하기 위하여 임의의 구조를 갖는 댁내 전화 선로의 전달 특성을 분석한 후, 고속의 데이터를 송 수신할 수 있도록 신호의 왜곡을 보상해 주는 적응형 등화기를 모의 실험을 통하여 구현하였다. 임의의 구조를 갖는 댁내 전화 선로에 대하여 ABCD행렬을 이용하여 전달 특성을 파악하였다. 그 결과, 각 지선에 의한 임퍼던스 부정합으로 인하여 주파수 전달 특성상 널(null)이 생기며, 이 영향은 시간축 상에서 지연된 펄스 형태의 임펄스 응답으로 나타남을 알 수 있었다. 이는 심볼간의 간섭을 유발하여 신호의 올바른 검출을 어렵게 한다. 이러한 간섭을 제거하기 위하여, 망 구조의 임의의 변화에 대한 적응형 등화기를 설계하여 모의 실험을 실시하였다. 그 결과에 따르면 1 Msps 전송 시 1.5 msec 내에 등화기가 수렴하고, 신호 대 잡음 비가 15 dB 이상에서 동작함을 알 수 있었다. 또한 $E_{b/}$ $N_{o}$ 와 비트 오류 확률의 관계를 살펴 본 결과, 데이터 통신이 가능한 $10^{-5}$ 이하의 비트 오류 확률을 얻기 위해서는 19 dB 이상의 $E_{b/}$ $N_{o}$ 값이 요구됨을 알 수 있었다.있었다.

• The Korean Journal of Physiology and Pharmacology
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• 제25권6호
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• pp.593-601
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• 2021

Primary cilia on kidney tubular cells play crucial roles in maintaining structure and physiological function. Emerging evidence indicates that the absence of primary cilia, and their length, are associated with kidney diseases. The length of primary cilia in kidney tubular epithelial cells depends, at least in part, on oxidative stress and extracellular signal-regulated kinase 1/2 (ERK) activation. Hydrogen sulfide (H₂S) is involved in antioxidant systems and the ERK signaling pathway. Therefore, in this study, we investigated the role of H₂S in primary cilia elongation and the downstream pathway. In cultured Madin-Darby Canine Kidney cells, the length of primary cilia gradually increased up to 4 days after the cells were grown to confluent monolayers. In addition, the expression of H₂S-producing enzyme increased concomitantly with primary cilia length. Treatment with NaHS, an exogenous H₂S donor, accelerated the elongation of primary cilia whereas DL-propargylglycine (a cystathionine γ-lyase inhibitor) and hydroxylamine (a cystathionine-β-synthase inhibitor) delayed their elongation. NaHS treatment increased ERK activation and Sec10 and Arl13b protein expression, both of which are involved in cilia formation and elongation. Treatment with U0126, an ERK inhibitor, delayed elongation of primary cilia and blocked the effect of NaHS-mediated primary cilia elongation and Sec10 and Arl13b upregulation. Finally, we also found that H₂S accelerated primary cilia elongation after ischemic kidney injury. These results indicate that H₂S lengthens primary cilia through ERK activation and a consequent increase in Sec10 and Arl13b expression, suggesting that H₂S and its downstream targets could be novel molecular targets for regulating primary cilia.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2007년도 춘계학술대회 학술발표 논문집 제17권 제1호
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• pp.421-428
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• 2007

본 논문은 퍼지 계층분석법을 이용하여 교통신호의 교차로망에서의 적합성에 대해서 논의한다. 교차로망에서의 교통신호는 현시, 주기등이 단일 교차로망의 교통신호 대안이라고 한다면 교차로 망에서의 교통신호 대안은 앞에 있는 교차로의 통행차량수와 지체차량수등 2개 이상의 교차로망의 상대적인 대안을 제시하여야 하므로 단일교차로의 교통신호 대안과는 다른 모습을 띠고 있다. 교통신호체계는 고정신호체계, 최적신호체계, 퍼지응용신호체계를 구별하여 응용단계가 높은 신호체계가 적합성이 톨음을 퍼지계층분석법을 이용하여 밝히고 이를 이용 새로운 체계의 교통신호 체계도 재시한다.

• Management Science and Financial Engineering
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• 제21권2호
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• pp.13-23
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• 2015

This study addresses the question as to whether the option prices have useful predictive information on the direction of stock markets by investigating a forecasting power of volatility curvatures and skewness premiums implicit in S&P 500 index option prices traded in Chicago Board Options Exchange. We begin by estimating implied volatility functions and risk neutral price densities every minute based on non-parametric method and then calculate volatility curvature and skewness premium using them. The rationale is that high volatility curvature or high skewness premium often leads to strong bullish sentiment among market participants. We found that the rate of return on the signal following trading strategy was significantly higher than that on the intraday buy-and-hold strategy, which indicates that the S&P500 index option prices have a strong forecasting power on the direction of stock index market. Another major finding is that the information contents of S&P 500 index option prices disappear within one minute, and so one minute-delayed signal following trading strategy would not lead to any excess return compared to a simple buy-and-hold strategy.

• 한국통신학회논문지
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• 제29권6A호
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• pp.600-606
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• 2004

본 논문에서는 인터리빙 딜레이 다이버시터 기법을 제안하고 이를 다중 코드 WCDMA 시스템에 적용한다. 제안 시스템에서의 딜레이 다이버시터 기법은 인터리빙 기법을 적용하여 잡음과 페이딩의 영향을 감쇄시켜 시스템 성능을 개선하고 인터리빙된 신호와 인터리빙 되지 않은 신호를 서로 다른 시간 간격을 두어 전송시켜 시간 다이버시터 이득을 얻으며 송신단에서 우너신호의 재전송 횟수를 적절히 증가시킴에 따라 수신 다이버시터이득을 효과적으로 얻을 수 있도록 한다. 또한 다수의 안테나 중 채널 상황이 좋은 안테나만을 선택하여 신호를 전송하는 안테나 선택 기법을 적용하여 제한된 전력을 효율적으로 사용하는 기법을 제안하였다. 컴퓨터 시뮬레이션을 통해 제안된 시스템이 기존 시스템에 비해 2dB 이상의 성능개선을 나타냄을 확인하였다.