• Journal of KIISE:Computer Systems and Theory
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• v.31 no.12
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• pp.726-734
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• 2004

This paper presents a facial animation method that enables the user to select a sequence of facial frames from the facial expression space, whose level of details the user can select hierarchically Our system creates the facial expression space from about 2400 captured facial frames. To represent the state of each expression, we use the distance matrix that represents the distance between pairs of feature points on the face. The shortest trajectories are found by dynamic programming. The space of facial expressions is multidimensional. To navigate this space, we visualize the space of expressions in 2D space by using the multidimensional scaling(MDS). But because there are too many facial expressions to select from, the user faces difficulty in navigating the space. So, we visualize the space hierarchically. To partition the space into a hierarchy of subspaces, we use fuzzy clustering. In the beginning, the system creates about 10 clusters from the space of 2400 facial expressions. Every tine the level increases, the system doubles the number of clusters. The cluster centers are displayed on 2D screen and are used as candidate key frames for key frame animation. The user selects new key frames along the navigation path of the previous level. At the maximum level, the user completes key frame specification. We let animators use the system to create example animations, and evaluate the system based on the results.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.853-856
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• 2013

최근 클라우드 서비스가 발전함에 따라 향상된 자원 활용과 소프트웨어 이식성을 증가시키기 위한 하드웨어 가상화 기술 또한 성장하고 있다. 가상화의 특성상 이를 구동하고 관리하는 시스템 관리자가 메모리, 하드디스크 드라이브와 같은 컴퓨팅 리소스에 접근할 수 있다. 관리자에 의한 Cold-boot Attack이나 내부 명령어를 통해서 메모리 상의 데이터가 유출될 수 있으므로 개인정보와 기밀문서와 같은 민감한 데이터의 노출 위험이 발생한다. C. Li 등은 Guest OS의 가상 메모리 기본 단위인 페이지를 암호화하여 관리자에게 메모리 상의 데이터가 노출되지 않도록 막는 기법을 제안하였다. 하지만 페이지 암호화에 사용되는 키를 하이퍼바이저상에서 구하는 과정에서 키가 노출된다는 문제점이 발생한다. 본 논문에서는 내부자 공격에 안전한 가상 머신 프레임워크를 제안한다. IOMMU(Input/Output Memory Management Unit)를 사용하여 직접 하드웨어 디바이스에 접근 가능한 Guest OS를 생성하고 TPM(Trusted Platform Module) 가상화를 사용하여 시스템 관리자가 알 수 없도록 암호 키를 생성/관리한다. 하이퍼바이저는 이 암호 키를 사용하여 Guest OS의 페이지를 암호화한다. 이를 통해 관리자에게 키를 노출하지 않고 Guest OS 메모리 상의 데이터를 보호할 수 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.9
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• pp.2063-2072
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• 2013

Smart Grid is the next-generation intelligent power grid that maximizes energy efficiency with the convergence of IT technologies and the existing power grid. It enables consumers to check power rates in real time for active power consumption. It also enables suppliers to measure their expected power generation load, which stabilizes the operation of the power system. However, there are high possibility that various kinds of security threats such as data exposure, data theft, and privacy invasion may occur in interactive communication with intelligent devices. Therefore, to establish a secure environment for responding to such security threat with the smart grid, the key management technique, which is the core of the development of a security mechanism, is required. Using a hash chain, this paper suggests a group key management mechanism that is efficiently applicable to the smart grid environment with its hierarchical structure, and analyzes the security and efficiency of the suggested group key management framework.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.5
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• pp.347-356
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• 2003

Camera pose and scene geometry estimation from video sequences is widely used in various areas such as image composition. Structure and motion recovery based on the auto calibration algorithm can insert synthetic 3D objects in real but un modeled scenes and create their views from the camera positions. However, most previous methods require bundle adjustment or non linear minimization process [or more precise results. This paper presents a new auto' calibration algorithm for video sequence based on two steps: the one is key frame selection, and the other removes the key frame with inaccurate camera matrix based on an absolute quadric estimation by LMedS. In the experimental results, we have demonstrated that the proposed method can achieve a precise camera pose estimation and scene geometry recovery without bundle adjustment. In addition, virtual objects have been inserted in the real images by using the camera trajectories.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.1
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• pp.46-57
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• 2001

To access the multimedia data, such as video data with temporal properties, the content-based image retrieval technique is required. Moreover, one of the basic techniques for content-based image retrieval is an extraction of representative key-frames. Not only did we implement this method, but also by analyzing the video data, we have proven the proposed method to be both effective and accurate. In addition, this method is expected to solve the real world problem of building video databases, as it is very useful in building an index.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6C
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• pp.368-375
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• 2011

In the distributed video coding system, the parity bits, which are generated in encoders, are used to reconstruct Wyner-Ziv frames. Since the original Wyner-Ziv frames are not known in decoders, the efficient correlation noise modeling for turbo or LDPC code is necessary. In this paper, an efficient correlation noise modeling method is proposed and the performance is analyzed. The method to estimate the quantization parameters for key frames, which are encoded using H.264 intraframe coding technique, is also proposed. The performance of the proposed system is evaluated by extensive computer simulations.

• The KIPS Transactions:PartD
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• v.10D no.4
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• pp.671-678
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• 2003

A digital video is usually very long temporally. requiring large storage capacity. Therefore, users want to watch pre-summarized video before they watch a large long video. Especially in the field of sports video, they want to watch a highlight video. Consequently, highlight video is used that the viewers decide whether it is valuable for them to watch the video or not. This paper proposes how to create soccer video highlight using the structural features of the caption such as temporal and spatial features. Caption frame intervals and caption key frames are extracted by using those structural features. And then, highlight video is created by using scene relocation, logical indexing and highlight creation rule. Finally. retrieval and browsing of highlight and video segment is performed by selection of item on browser.

• Journal of the Korea Society of Computer and Information
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• v.10 no.5 s.37
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• pp.65-76
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• 2005

A digital video is a very long data that requires large-capacity storage space. As such, prior to watching a long original video, video watchers want to watch a summarized version of the video. In the field of sports, in particular, highlights videos are frequently watched. In short, a highlights video allows a video watcher to determine whether the highlights video is well worth watching. This paper proposes a scheme for creating soccer video highlights using the structural features of captions in terms of time and space. Such structural features are used to extract caption frame intervals and caption keyframes. A highlights video is created through resetting shots for caption keyframes, by means of logical indexing, and through the use of the rule for creating highlights. Finally, highlights videos and video segments can be searched and browsed in a way that allows the video watcher to select his/her desired items from the browser.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.340-342
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• 2012

사람관련 사건을 실시간으로 인지하거나 빠르게 사건 관련 증거를 확보하기 위해서는 대량의 비디오 감시 데이터로부터 사람 관련 정보를 빠르게 찾을 수 있어야 하는데 기존의 시스템에서는 모든 프레임으로부터 주석 편집자가 수작업으로 관련 정보를 추출하여 색인해야 하기 때문에 많은 주석 시간을 필요로 하는 문제를 갖고 있었다. 본 논문에서는 대량의 방범용 비디오 감시 데이터로부터 사람 관련 사건 정보를 빠르게 찾을 수 있도록 지원하기 위해 전체 비디오 데이터 중에서 사람의 출현과 퇴장을 기준으로 키 프레임 구간을 추출하고, 키 프레임에서만 사람 관련 정보를 추출하여 사람 관련 주요 정보를 자동으로 추출하여 XML 스키마 형식으로 색인하는 비디오 주석 시스템을 개발하였다. 또한, 색인된 XML 데이터에 대해 구조 및 내용 기반 질의를 이용하여 쉽고 빠르게 검색할 수 있도록 하기 위해 XPATH 질의 인터페이스를 구현 하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.637-640
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• 2004

논문에서는 자막의 구조적 특징을 이용하여 축구 비디오 하이라이트를 생성하는 방법을 제시한다. 자막의 구조적 특징은 자막이 갖는 시간적 특징과 공간적 특징으로서 이러한 구조적 특징을 이용하여 자막 프레임 구간과 자막 키 프레임을 추출한다. 그리고 하이라이트 비디오는 자막 키 프레임들에 대한 장면 재설정과 논리적 색인화 및 하이라이트 생성 규칙을 이용하여 생성한다. 마지막으로, 브라우저를 통한 사용자의 항목 선택에 의하여 하이라이트 비디오와 비디오 세그먼트에 대한 검색과 브라우징을 수행할 수 있다.