• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권11호
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• pp.5624-5638
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• 2016

A novel method based on Surf points is proposed to detect and lock-track single ground target in aerial videos. Videos captured by moving cameras contain complex motions, which bring difficulty in moving object detection. Our approach contains three parts: moving target template detection, search area estimation and target tracking. Global motion estimation and compensation are first made by grids-sampling Surf points selecting and matching. And then, the single ground target is detected by joint spatial-temporal information processing. The temporal process is made by calculating difference between compensated reference and current image and the spatial process is implementing morphological operations and adaptive binarization. The second part improves KALMAN filter with surf points scale information to predict target position and search area adaptively. Lastly, the local Surf points of target template are matched in this search region to realize target tracking. The long-term tracking is updated following target scaling, occlusion and large deformation. Experimental results show that the algorithm can correctly detect small moving target in dynamic scenes with complex motions. It is robust to vehicle dithering and target scale changing, rotation, especially partial occlusion or temporal complete occlusion. Comparing with traditional algorithms, our method enables real time operation, processing $520{\times}390$ frames at around 15fps.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.79-83
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• 2000

A sliding mode fuzzy control (SMFC) with disturbance estimator is applied to design a controller for the third generation benchmark problem on an wind-excited building. A distinctive feature in vibration control of large civil infrastructure is the existence of large disturbances, such as wind, earthquake, and sea wave forces. Those disturbances govern the behavior of the structure, however, they cannot be precisely measured, especially for the case of wind-induced vibration control. Since the structural accelerations are measured only at a limited number of locations without the measurement of the wind forces, the structure of the conventional control may have the feed-back loop only. General structure of the SMFC is composed of a compensation part and a convergent part. The compensation part prevents the system diverge, and the convergent part makes the system converge to the sliding surface. The compensation part uses not only the structural response measurement but also the disturbance measurement, so the SMFC has a feed-back loop and a feed-forward loop. To realize the virtual feed-forward loop for the wind-induced vibration control, disturbance estimation filter is introduced. the structure of the filter is constructed based on an auto regressive model for the stochastic wind force. This filter estimates the wind force at each time instance based on the measured structural responses and the stochastic information of the wind force. For the verification of the proposed algorithm, a numerical simulation is carried out on the benchmark problem of a wind-excited building. The results indicate that the present control algorithm is very efficient for reducing the wind-induced vibration and that the performance indices improve as the filter for wind force estimation is employed.

• 한국멀티미디어학회논문지
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• 제13권2호
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• pp.225-236
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• 2010

본 논문은 카메라 영상 정보와 기울기 센서 정보를 통합한 바이모달 응급상황 인식방법을 제안한다. 제안된 방법은 어느 한 센서가 오작동 하거나 사용자가 착용형 기울기 센서를 착용하지 않거나, 영상 획득의 어려움이 있는 욕실과 같은 곳에 있는 경우에도 응급 상황을 감지하여 센서 간에 상호 협력과 보완을 함으로써 응급 상황을 인식할 수 있다. 본 논문에서는 HMM 학습 및 인식을 통해 걷는 동작, 바닥에 앉는 동작, 소파에 앉는 동작, 눕는 동작, 기절 동작을 판단할 수 있도록 하였다. 영상의 특징 벡터와 기울기 센서의 특징 벡터를 결합하여 학습하고 인식했을 때, 인식률의 향상을 가져올 수 있었다. 또한 다양한 조명의 변화에도 적응적 배경 모델을 통해 움직이는 객체를 강건하게 검출할 수 있어서 높은 인식률을 유지할 수 있었다.

• 한국멀티미디어학회논문지
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• 제13권7호
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• pp.1088-1094
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• 2010

영상 인증 알고리즘은 군사, 의료 분야 및 스캔된 증빙 문서, 계약서 등 민감한 분야에서 필요하며 원본에 대한 위조 여부를 증명하여야 한다. 인증 분야에서는 지각적 비가시성과 연성이 필요하다. 워터마크의 용량은 클수록 좋으며, 워터마크된 영상만으로 워터마크 추출이 가능한 블라인드 워터마킹은 구현이 어렵지만 가장 바람직하다. 또한 워터마크 추출 과정에서 거짓 긍정과 거짓 부정의 오류가 발생하지 않는 신뢰성은 필수적이다. 이 연구에서는 DCT의 고주파 영역에 계수를 조정하여 워터마크를 삽입하며, 신뢰성을 높이기 위하여 필요하다면 원본 영상의 명도 히스토그램을 보정하는 방법을 사용한다. 실험 결과에서는 제안한 알고리즘이 높은 PSNR 값에 의한 지각적 비가시성, 연성, 블라인드 특성을 만족시키며, 스테가노그라피 응용에 적용 가능할 정도로 큰 워터마크의 용량과 히스토그램의 보정에 의한 신뢰성을 가진 것으로 나타났다.

• 한국전자통신학회논문지
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• 제19권1호
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• pp.65-76
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• 2024

최근 해상풍력산업이 활성화되면서 기존 화력 발전소 규모의 400MW 급 발전단지들이 개발되고 있다. 재생에너지는 에너지원에 따라 간헐성이 큰 특성이 있고, 최신 재생에너지 발전설비들은 제어기능을 갖는 인버터 기술로 구성되는 특징이 있다. 이러한 재생에너지원의 계통연계 확대에 따라 전력계통 접속을 위한 그리드코드도 점점 구체화되고 있고, 이에 따라 관련 검토도 활발히 진행되고 있다. 본 논문에서는 그리드 코드 준수를 위해 여러 해상풍력 발전단지들을 통합하여 공동접속설비로 접속하는 경우, 최적 무효전력 보상용량 선정 방법에 대해 제안한다. 그리드 코드의 요구조건을 기반으로, 전북 서남해 400MW 풍력발전단지의 무효전력 보상과 과도안정도를 분석한다. 이 분석은 PSS/E를 사용하여 각 터빈 배치안과 케이블 데이터로 발전단지 DB를 구축하고, 내·외부망 케이블의 충전전류에 의한 무효전력과 연계점에서 무효전력 보상용량을 산출한다. 또한 전력계통 DB에 연계해서 정적, 동적 안정도를 고찰한다.

• 한국산업융합학회 논문집
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• 제23권3호
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• pp.433-444
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• 2020

This study proposes a method to improve the sleep stage and efficiency estimation of sleep apnea patients using a UWB (Ultra-Wideband) radar. Motion and respiration extracted from the radar signal were used. Respiratory signal disturbances by motion artifacts and irregular respiration patterns of sleep apnea patients are compensated for in the preprocessing stage. Preprocessing calculates the standard deviation of the respiration signal for a shift window of 15 seconds to estimate thresholds for compensation and applies it to the breathing signal. The method for estimating the sleep stage is based on the difference in amplitude of two kinds of smoothed respirations signals. In smoothing, the window size is set to 10 seconds and 34 seconds, respectively. The estimated feature was processed by the k-nearest neighbor classifier and the feature filtering model to discriminate between the sleep periods of the rapid eye movement (REM) and non-rapid eye movement (NREM). The feature filtering model reflects the characteristics of the REM sleep that occur continuously and the characteristics that mainly occur in the latter part of this stage. The sleep efficiency is estimated by using the sleep onset time and motion events. Sleep onset time uses estimated features from the gradient changes of the breathing signal. A motion event was applied based on the estimated energy change in the UWB signal. Sleep efficiency and sleep stage accuracy were assessed with polysomnography. The average sleep efficiency and sleep stage accuracy were estimated respectively to be about 96.3% and 88.8% in 18 sleep apnea subjects.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(4)
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• pp.143-146
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• 2000

Motion Estimation/compensation(ME/MC) is one of the efficient interframe ceding techniques for its ability to reduce the high redundancy between successive frames of an image sequence. Calculating the blocking matching takes most of the encoding time. In this paper a new fast block matching algorithm(BMA) is developed for motion estimation and for reduction of the computation time to search motion vectors. The feature of the new algorithm comes from the center-biased checking concept and the trend of pixel movements. At first, Motion Vector(MV) is searched in ${\pm}$1 of search area and then the motion estimation is exploited in the rest block. The ASP and MSE of the proposed search algorithm show good performance.

• 한국인터넷방송통신학회논문지
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• 제11권3호
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• pp.175-179
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• 2011

본 논문에서는 모바일 환경에서의 음성인식 개선에 관한 내용으로 기존의 HMM에서 특징보상기법을을 적용한 방식으로 예측잡음이 아닌 실제 오염된 데이터를 적용하여 인식모델을 잡음상황에 맞도록 적응시키는 모델적응 HMM을 사용하였다. 음성인식 시 기존의 방법에서는 주변노이즈를 고려하지 않은 참조패턴을 사용하였으나 본 연구에서는 주변노이즈를 고려한 참조패턴을 생성하여 인식률을 향상 시키는 방법으로 모바일 환경에서의 음성 인식률을 향상 시켰다.

• 대한음성학회지:말소리
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• 제46호
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• pp.77-86
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• 2003

Channel distortion and coarticulation effect in the Korean connected digit telephone speech make it difficult to achieve high performance of connected digit recognition in the telephone environment. In this paper, as a basic research to improve the recognition performance of Korean connected digit telephone speech, recognition error patterns are investigated and analyzed. Korean connected digit telephone speech database released by SiTEC and HTK system are used for recognition experiments. Both DWFBA and MRTCN methods are used for feature extraction and channel compensation, respectively. Experimental results are discussed with our findings.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.42-47
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• 2011

Automatic generation control (AGC) is an important function for load frequency control, which is being implemented in Energy Management System (EMS). A key feature of AGC is to back up governors to enhance the performance of frequency control. The governor regulates system frequency in several to ten seconds, while the droop control concept results in steady-state control error. AGC is a supplementary tool for compensation of the steady-state error caused by the droop setting of the governors. As the AGC target is delivered to each generator as an open loop control target, the generator output is not guaranteed to follow the AGC target. In this paper, we introduce generating unit controller (GUC) control block, which has the purpose of enabling the generator output to track the AGC target while maintaining the governor performance. We also address the tuning methods of GUC for better performance of AGC in the Korea Energy Management System (K-EMS).