• 한국소음진동공학회논문집
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• 제26권6_spc호
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• pp.736-743
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• 2016

This study describes optimization methods for adjustment of helicopter main rotor tracking and balancing (RTB). RTB is a essential process for helicopter operation and maintenance. Linear and non-linear models were developed with past RTB test results for estimation of RTB adjustment. Then global and sequential optimization methods were applied to the each of models. Utilization of the individual optimization method with each model is hard to fulfill the RTB requirements because of different characteristics of each blade. Therefore an ensemble model was used to integrate every estimated adjustment result, and an adaptive method was also applied to adjustment values of the linear model to update for next estimations. The goal of this developed RTB adjustment optimization program is to achieve the requirements within 2 run. Additional tests for comparison of weight factor of the ensemble model are however necessary.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.225-230
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• 2002

Machine of textiles let off is equipment supplying constantly fabrics. Nowdays, as it is replaced band - brake type with hydraulic motor driven type, we looked into characteristic of hydraulic solenoid pilot direction valve(SPDV) for controlling acceleration performance of hydraulic motor. This study deals with controlling the initial speed of textiles let off machine. Finally, to control the initial speed of hydraulic motor, we controlled the adjustment screw of SPDV by a hand. Test which was carried out in the laboratory shows that initial speed of textiles let off could be improved by controlling adjustment screw of SPDV. Also, the results of experiment work were compared with dynamic characteristic of other on/off solenoid direction valve(SDV).

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2007년도 추계학술대회 및 제23회 정기총회
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• pp.255-256
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• 2007

컨테이너터미널의 장치장으로 반입되는 컨테이너의 위치가 잘못될 경우 컨테이너 적하 작업 시 재취급 발생과 크레인 이동 시간 증가로 인해 작업 시간이 지연될 수 있다. 최적의 장치 위치를 결정하기 위해서는 크레인 간섭, 컨테이너 그를, 적재단수 등 여러 가지 요소를 고려해야 하고, 이 요소들의 중요도를 반영하는 가중치를 결정해야 한다. 본 연구에서는 온라인 탐색을 바탕으로 장치 위치 결정 요소에 대한 가중치를 동적으로 조정하는 온라인 탐색 알고리즘을 제안한다.

• 대한기계학회논문집
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• 제18권12호
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• pp.3149-3158
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• 1994

In this paper, using the formulation of dynamic equivalent load considering the effects of moment load and the equation to estimate the cage rotational speed, the new life equation of deep groove ball bearing under radial and moment loads was proposed. Fatigue life test apparatus with the measuring equipment of shaft and cage speed was designed and developed to be capable of subjecting combined radial and moment load. Fatigue life tests were executed by sudden death test method and the reliability of fatigue lives was evaluated by Weibull distribution analysis. From the results of fatigue tests and analysis, the relationships between film parameters and life adjustment factors were acquired. And it was turned out that so as to estimate the effect of moment load on fatigue life, the life adjustment factor as well as the dynamic equivalent load must be taken into account.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.281-284
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• 2004

This paper presents the design and implementation of a QoS based enhanced collaboration system in MDO. This is an efficient distributed communication tool between designers. It supports text communication, audio/video communication, file transfer and XML data sending/receiving. Specially, this system supports a dynamic QoS self-adaptation by using the improved direct adjustment algorithm (DAA+). The original direct adjustment algorithm adjusts the transmission rate according to the congestion level of the network, based on the end to end real time transport protocol (RTP), and controls the transmission rate by using the information of loss ratio in real time transport control protocol (RTCP). But the direct adjustment algorithm does not consider when the RTCP packets are lost. We suggest an improved direct adjustment algorithm to solve this problem. We apply our improved direct adjustment algorithm to our of QoS (Quality of Service) [1] based collaboration system and show the improved performance of transmission rate and loss ratio.

• 방송공학회논문지
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• 제23권2호
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• pp.302-315
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• 2018

지각 양자기 광전 변환 함수의 생략 Taylor 급수를 이용한 선형 근사는 휘도 조절 기법의 하드웨어 구현에 적합한 폐쇄형 솔루션을 제공할 수 있지만, 600~3,900 cd/m2 구간의 선형 영역 광 신호에 대해 상대적으로 큰 근사 오차를 유발한다. 이러한 비-선형 광전 변환 함수의 근사 오차 개선을 위해, 본 논문에서는 새로운 선형 모델을 제안한다. 제안된 선형 근사 모델은 그 근사 범위를 고려한 직선의 위치 교정 및 기울기 산출을 수행한다. 제안 모델의 성능 검증을 위해, 다양한 고-휘도 실험 시퀀스를 대상으로 모의실험을 수행하였고, 이를 통해 채도가 높은 색상을 포함하는 시퀀스에 대해서는, Taylor 급수를 기반으로 한 기존의 선형 모델에 비해, 휘도 신호의 t-PSNR을 4.65dB 만큼 개선할 수 있는 높은 성능 향상을 확인하였다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.334-336
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• 2009

Estimation and correction of color temperature of digital images are basis of white balance adjustment after image acquisition stage. White balance is one of the most important image processing techniques for subjective image quality enhancement. Correction of color temperature is applied for white balance adjustment or for changing the mood of a picture. A picture taken under the daylight can be changed to have a mood of sunset or cloudy day, for example. We evaluate color temperature transformation of high dynamic range images in linear and log domain, and we conclude that linear domain transformation shows better results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1371-1373
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• 1996

A clustering algorithms with dynamic adjustment of learning rate for GBFCM(Gradient Based FCM) is proposed in this paper. This algorithm combines two idea of dynamic K-means algorithms and GBFCM : learning rate variation with entropy concept and continuous membership grade. To evaluate dynamic GBFCM, we made comparisons with Kohonen's Self-Organizing Map over several tutorial examples and image compression. The results show that DGBFCM(Dynamic GBFCM) gives superior performance over Kohonen's algorithm in terms of signal-to-noise.

• 자원ㆍ환경경제연구
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• 제22권2호
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• pp.393-410
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• 2013

본 논문에서는 우리나라 휘발유 가격의 비선형 동적 조정 과정을 분석하였다. 이를 위하여 Threshold Vector Error Correction Model(TVECM)을 사용하였다. 구체적으로는 Hansen (1999)과 Lo and Zivot(2001)이 제안한 부트스트랩(bootstrap)기법을 적용하여 three-regime TVECM의 타당성을 확인한 후 사용하였다. 분석대상은 서울과 각 지역의 휘발유 가격 차이인데 서울-부산, 서울-대구, 서울-인천, 서울-광주, 서울-대전, 서울-울산, 서울-강원, 서울-충북, 서울-전북 등 총 9개 휘발유 가격차이 묶음을 다루었다. 추정결과 우리나라 휘발유 가격 조정과정은 비선형적인 것으로 나타났다. 또한 서울-대전, 서울-대구, 서울-울산의 거래비용이 큰 것으로 추정되었다. 거래비용은 지리적 거리에 반드시 비례하지 않는 것으로 나타났으며, 이는 수송비용이 거래비용의 주요한 요인이 아님을 의미한다. 거래비용은 공급측면의 경쟁정도에 의존할 것으로 추정된다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.741-744
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• 2008

In this paper, tone mapping method by local contrast and detail enhancement for High Dynamic Range (HDR) is proposed. By applying Piecewise Dynamic Range Histogram Adjustment (PDRHA) and Detail Enhancement Volume (DEV) with decomposed layers, tone mapping is performed effectively. The experimental results show that the proposed method preserves local contrast and overall impression with naturalness of original images.