• Journal of IKEEE
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• v.18 no.1
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• pp.1-7
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• 2014

In this paper, we suggest an improved Viola-Jones detection framework for the efficient feature selection and the fast rejection method of the sub-window. Our object detector has low computational complexity because it rejects sub-windows until specific threshold. Owing to using same framework, detection performance is same with the existing Viola-Jones detector. We measure the number of average feature calculation about MIT-CMU test set. As a result of the experiment, the number of average feature calculation is reduced to 45.5% and the detection speed is improved about 58.5% compared with the previous algorithm.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.68-69
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• 2001

스테레오 물체 추적을 위해서는 추적 물체의 현재 위치를 추출하는 것이 선행 되어야한다. 입력된 좌측 영상과 이전 프레임에서 얻은 윈도우 마스크(window mask)의 기준 영상간에 식 (1)의 MSE 알고리즘을 적용하였다. 여기에서 윈도우 마스크의 기준 영상은 초기에만 추적을 원하는 물체를 마스크로 잡아(locking) 초기화 시켜 주면, 이후에는 스스로 계속 갱신(update)하게 된다. (중략)

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.273-276
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• 2001

CELP 부호화기는 선형 예측 합성에 의한 분석 부호화의 원칙에 기본을 두고 있다. 그리고 음성 신호의 스펙트럼을 LPC 분석을 통해 부호화하는데 고정 윈도우를 사용하여 부호화한다. 그러나 음성신호는 화자의 발성속도에 따라 파형의 변화가 시간적으로 빠르게 변화하기도 하고, 반대로 유사한 파형이 일정시간 유지되기도 한다. 따라서 윈도우의 크기를 발성속도에 맞추어 분석한다면 보다 효율적인 부호화를 할 수 있다. 본 논문에서는 발성속도에 따라 전송률을 달리 적용하는 방법을 제안한다. 발성속도의 측정은 스펙트럼 변화도를 이용하여 측정하였고, 발성속도가 빠를 때는 프레임 크기를 줄여 시간적으로 빠르게 변화하는 신호에 적응적으로 분석하고 대신 파라미터 표현에 비트를 줄인다. 반대로 발성속도가 느릴 때는 프레임 크기를 키우고 파라미터 표현에 비트를 더 할당한다. 제안한 방법을 실험하기 위해 G.723.1 5.3kbps ACELP 부호화기를 이용하였다 음질의 열하 없이 평균 16.34% 전송률 감소효과를 얻을 수 있었다.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.232-235
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• 2004

This is the preliminary study to develop composite window frame of commercial aircraft using VaRTM process. For two candidate carbon fabric(triaxial fabric, sleeving braider dry carbon fiber), specimens were fabricated using VaRTM process ,and then the physical & mechanical tests were performed to gain material property according to ASTM. FEM analysis for each candidate carbon fabric were performed to find the minimum ply number and weight for composite window frame. In this study Tsai-Wu strength failure criteria was utilized to evaluate the safety of structure.

• 정보화사회
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• s.108
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• pp.57-62
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• 1996

윈도우 NT가 이제는 어떤 하드웨어에 구애받지 않고 메인프레임부터 워크 스테이션, PC, 데스크탑PC까지 전체를 통괄하는 하나의 운영시스템으로 변해나갈 것이고 이러한 부분들이 앞으로 시장에서 마이크로 소프트의 위치를 상당히 강화시켜 주리라 생각된다.

• The Journal of the Acoustical Society of Korea
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• v.22 no.8
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• pp.717-726
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• 2003

This paper presents the methods that design the Wavelet-based pitch detector for 2,4 kbps Harmonic-CELP Coder, and that achieve the effective waveform interpolation by decision window shape of the transition region, Waveform interpolation coder operates by encoding one pitch-period-sized segment, a prototype segment, of speech for each frame, generate the smooth waveform interpolation between the prototype segments for voiced frame, But, harmonic synthesis of the prototype waveforms between previous frame and current frame occur not only waveform errors but also discontinuity at frame boundary on that case of pitch halving or doubling, In addtion, in transition region since waveform interpolation coder synthesizes the excitation waveform by using overlap-add with triangularity window, therefore, Harmonic-CELP fail to model the instantaneous increasing speech and synthesis waveform linearly increases, First of all, in order to detect the precise pitch period, we use the hybrid 1st pitch detector, and increse the precision by using 2nd ACF-pitch detector, Next, in order to modify excitation window, we detect the onset, offset of frame by GCI, As the result, pitch doubling is removed and pitch error rate is decreased 5.4% in comparison with ACF, and is decreased 2,66% in comparison with wavelet detector, MOS test improve 0.13 at transition region.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.636-644
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• 2015

This research aims to suggest methods to improve object tracking performance by combining CAM shift algorithm with 8-way search window, and reduce arithmetic operation by reducing the number of frame used for tracking. CAM shift has its adverse effect in tracking methods using signature color or having difficulty in tracking rapidly moving object. To resolve this, moving search window of CAM shift makes it possible to more accurately track high-speed moving object after finding object by conducting 8-way search by using information at a final successful timing point from a timing point missing tracking object. Moreover, hardware development led to increased unnecessary arithmetic operation by increasing the number of frame produced per second, which indicates efficiency can be enhanced by reducing the number of frame used in tracking to reduce unnecessary arithmetic operation.

• The Journal of the Acoustical Society of Korea
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• v.37 no.2
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• pp.110-117
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• 2018

In this paper, we propose a low delay window switching MDCT (Modified Discrete Cosine Transform) method for speech/audio coder. The window switching algorithm is used to reduce the degradation of sound quality in non-stationary trasient duration and to reduce the algorithm delay by using the low delay TDAC (Time Domain Aliasing Cancellation). While the conventional window switching algorithms uses overlap-add with different lengths, the proposed method uses the fixed overlap add length. It results the reduction of algorithm delay by half and 1 bit reduction in frame indication information by using 2 window types. We apply the proposed algorithm to G.729.1 based on MDCT in order to evaluate the performance. The propose method shows the reduction of algorithm delay by half while speech quality of the proposed method maintains same as the conventional method.

• The KIPS Transactions:PartB
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• v.14B no.7
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• pp.473-480
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• 2007

Feature tracking in video frame sequences has suffered from the instability and the frequent failure of feature matching between two successive frames. In this paper, we propose a robust 2D feature tracking method that is stable to long video sequences. To improve the stability of feature tracking, we predict the spatial movement in the current image frame using the state variables. The predicted current movement is used for the initialization of the search window. By computing the feature similarities in the search window, we refine the current feature positions. Then, the current feature states are updated. This tracking process is repeated for each input frame. To reduce false matches, the outlier rejection stage is also introduced. Experimental results from real video sequences showed that the proposed method performs stable feature tracking for long frame sequences.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.1
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• pp.93-102
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• 1999

In this paper, we propose a data model and a retrieval method for content-based video query After partitioning a video into frame sets of same length which is called video-window, each video-window can be mapped to a point in a multidimensional space. A video can be represented a trajectory by connection of neighboring video-window in a multidimensional space. The similarity between two video-windows is defined as the euclidean distance of two points in multidimensional space, and the similarity between two video segments of arbitrary length is obtained by comparing corresponding trajectory. A new retrieval method with filtering and refinement step if developed, which return correct results and makes retrieval speed increase by 4.7 times approximately in comparison to a method without filtering and refinement step.