• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.549-551
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• 2012

본 논문에서는 기존의 화소값 차영상 기법이 저속으로 움직이는 물체의 동작정보 감지에 취약한 점을 보완하기 위하여 실시간 영상 처리를 목적으로 연속된 프레임(Frame)에서 움직임이 있는 프레임을 찾아내고, 움직임 영역을 추출하는 움직임 검출에 관한 연구를 통해 웹캠 기반의 객체 감지시스템을 제안하였다. 제안 시스템은 단일 객체뿐 아니라 다중 객체의 움직임까지 파악할 수 있다는 장점을 가지고 있다.

• Korean journal of communication and information
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• v.48
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• pp.231-256
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• 2009

The purpose of this study is that we regard the notion of reality that television viewers feel as presence, point out problem of measurement tool that appropriate for TV, clarify the subordinate concept of presence, and develop measurement tool that have reliability and validity. To achieve this, we paid attention to reality of television as a determinant of presence and tried to elicit proper subcategories. That is, we progressed two steps research that distinguished external characteristic and content of the media into sensible reality and cognitive reality, and develop measure item and verified statistical validity. We analyzed the second research result about measurement category of presence selected by first research and then we did Exploratory factor analysis and Confirmatory factor analysis. As a result, the first characteristic that make people experience presence is sensible reality, that is, it is the factor of sensible faithfullness, image faithfullness, and image reality as the form factor of the media. The second characteristic is cognitive reality. That is the factor of social reality, relational reality, and practical reality as the factor of media content. Synthesizing these subordinate factor, we can conceptualize presence experience as a reality of media form and content in HDTV viewing environment.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.5
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• pp.602-608
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• 1999

멀티미디어 서비스를 제공하는 미래의 이동통신 시스템에서는 데이터의 신뢰성 있는 전송을 위해 물리 계층에서 제공하는 프레임 에러율을 감소시켜야한다. 이를 위해 라디오링크프로토콜(RLP : radio link protocol) 계층에서는 ARQ(automatic repeat request)기법을 사용한다. 본 논문에서는 멀티미디어 서비스를 제공하는 차세대 이동통신 시스템에 적용될수 있는 새로운 SR(Selective repeat) ARQ 기법을 제안하고 그 성능을 분석한다. 제안하는 SR 기법은 재전송이 반복될수록 NAK(negative acknowledge)수와 재전송 프레임수를 지수적으로 (exponentially)증가시킴으로써 프레임손실확률을 감소시킨다. 또한 제안한 SR 기법의 성능을 기존의 전형적인 SR 기법 및 IS-707의 SR 기법과 비교하였다. 비교결과, 제안한 SR 기법은 프레임 손실 확률과 프레임 전송지연 측면에서 다른 두 비교대상 Sr 기법들에 비해 더 나은 성능을 제공한다.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.839-842
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• 2009

It is used to differential image for moving object detection in general. But it is difficult to detect the accurate detection which uses differential image between frames. In this paper, the proposed method overcome the noise that is generated by camera, grabber card, or weather condition. It extract to moving big object such as human or vehicle. The proposed method process morphological filtering and binary for the image with noise, reduce error. We are expect to apply to a real-time moving object detection system at fog condition, pass the limit of the object detection method using the differential image.

• Progress in Medical Physics
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• v.2 no.2
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• pp.183-192
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• 1991

Ophthalmoscopy following the intravenous injection of fluorescein has gained great diagnostic importance in ophthalmology. This technique provides sequential evaluation of the anatomic and physiologic status of the choroidal and retinal vasculature. In order to detect the changes between fluorescein ocular fundus image frames, the direct subtraction of the two frames is inadequate because of geometric distortions and background gray level differences in two images. In this study, a scheme for the correction of the geometric distortions is proposed. Precise control point coordinate values for transformation functions are manually determined after the process including a series of blood vessel detection and thinning, and one frame is mapped to another, and then a geometric distortion corrected image is obtained. When the corrected image is used in interframe change detections, a sucessful result is ensured.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.475-477
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• 2001

본 논문에서는 버스에 설치되어 있는 비디오 카메라의 연속된 승차 영상과 추출해둔 배경 영상간의 영상차 분석을 통해 승객이 특정 구역을 통과하는 것을 감지하여 계수하는 방법을 연구하였다. 배경 영상은 운행 시와 같이 배경이 급변할 때는 연속된 두 프레임의 영상차를 이용하여 동적으로 배경 영상을 얻고 정차 시에는 배경 영상을 승차 영상과 비교하여 보정하여 주는 방법으로 최적화된 배경 영상을 얻어내었다. 본 시스템은 실제 상황에서 얻어진 비디오 영상에 적용하여 93.6%의 계수 성공률을 얻어내었다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.6
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• pp.105-114
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• 2011

The snake algorithm is widely adopted to track objects by extracting the active contour of the object from background. However, it fails to track the target converging to the background if there exists background whose gradient is greater than that of the pixels on the contour. Also, the contour may shrink when the target moves fast and the snake algorithm misses the boundary of the object in its searching window. To alleviate these problems, we propose an improved algorithm that can track object contour more robustly. Firstly, we propose two external energy functions, the edge energy and the contrast energy. One is designed to give more weight to the gradient on the boundary and the other to reflect the contrast difference between the object and background. Secondly, by computing the motion vector of the contour from the difference of the two consecutive frames, we can move the snake pointers of the previous frame near the region where the object boundary is probable at the current frame. Computer experiments show that the proposed method is more robust to the complicated background than the previously known methods and can track the object with fast movement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6A
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• pp.445-454
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• 2005

To measure the performance of call quality, we have built the experiment environment and observed that the delay caused by encapsulation between internet and VoIP telephones is under 5ms at most. The major delay is assumed to be the time required to capsulate the packet for tunnelling of VPN. Because the difference of average delay time is under $4ms{\sim}5ms$, the difference of call quality between VoIP and VoIP telephone adopting VPN is negligible. We have concluded that the capsulation process between PAC and PNS is the major factor influencing the network load by changing the number of fames in a packet during communication Also, we have concluded that the most suitable frame numbers is tow or three by adding the frame numbers in a packet to obtain the suitable frames in a packet and setting up end-to-end delay under 150ms.

• The Journal of the Acoustical Society of Korea
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• v.15 no.5
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• pp.99-106
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• 1996

The noise of a compressor is a major contributor to overall noise radiated from the refrigerator. The major source of the noise is radiated by the vibration of the compressor shell. In this study, to identify the dynamic characteristics of compressor shell, a compressor shell is divided into several components and these are analyzed with a commercial FEM(Finite Element Method) package such as MSC/NASTRAN. Using substructure synthesis method, the dynamic characteristics of the total system is identified. The coherence of each component to the total system is computed by using strain and kinetic energy. To increase the frequency of the first resonance mode which is most effective mode to the noise of the compressor shell, the improving strategy of dynamic characteristics is suggested by changing mass and stiffness of the coherence component to the first mode.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7A
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• pp.1046-1051
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• 1999

It is well known that Parallel Concatenated Convolutional Codes(turbo codes) has a good performance for long block sizes. This thesis has analyzed the performance of turbo code which is based on voice or control frames with short frame sizes in the future mobile communication system. Also, at the similar decoding complexity, the performance of turbo code and convolutional codes in the speech/control frames, and the applicability of this system are considered. As a result, turbo code in short frame sizes present the performance of a BER of $10^{-3}$ or more over 3 iterations in the future mobile communication system. However, at a BER of $10^{-3}$ , if the same complexity is considered, the performance of rate 1/2 turbo code with K = 5 is better than that of convolutional code with K = 9 at low $E_b/N_0$, and the performance of turbo code with K = 3 is superior to that of convolutional code with K = 7. Rate 1/3 turbo code with K = 3 and 5 have similar to performance of rate 1/2 turbo code.