• Journal of the Korean Society for Precision Engineering
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• v.20 no.5
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• pp.47-56
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• 2003

Geometric cutting-simulation and verification play an important role in detecting NC machining errors in mold & die manufacturing and thereby reducing correcting time & cost on the shop floor. Current researches in the area may be categorized into view-based, solid-based, and discrete vector-based methods mainly depending on workpiece models. Each methodology has its own strengths and weaknesses in terms of computing speed, representation accuracy, and its ability of numerical inspection. The paper proposes a hybrid modeling scheme for workpiece representation with z-map model and discrete vector model, which performs 3-axis and 5-axis cutting-simulation via tool swept surface construction by connecting a sequence of silhouette curves.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.877-880
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• 2000

In this paper, we develop an algorithm of soccer image sequences mosaicing using reverse affine transform. The continuous mosaic images of soccer ground field allows the user/viewer to view a “wide picture” of the player’s actions The first step of our algorithm is to automatic detection and tracking player, ball and some lines such as center circle, sideline, penalty line and so on. For this purpose, we use the ground field extraction algorithm using color information and player and line detection algorithm using four P-rules and two L-rules. The second step is Affine transform to map the points from image to model coordinate using predefined and pre-detected four points. General Affine transformation has many holes in target image. In order to delete these holes, we use reverse Affine transform. We tested our method in real image sequence and the experimental results are given.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.199-202
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• 2003

An effective method is proposed for detecting, acquisition and tracking of a moving object using a disturbance map method in complex image sequences. A significant moving object is detected and tracked within the field of view by computing a modified disturbance map method between an Input image and a temporal average image. This method is very efficient in the serveillance application of digital CCTV and an automatic tracking camera. Experimental results using a real image sequence confirmed that the proposed method can effectively detect and track a significant moving object in complex image sequences.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.4
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• pp.439-446
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• 2003

In this paper, a single sign-on system has been designed and implemented. The purpose of the proposed system is that a user logs in once using a single password and gets authenticated access to all the servers that he is authorized to use without sending any passwords over the network. The proposed system involves the use of digital signature and cryptographic authentication protocols. For its implementation, a public-key infrastructure is also designed and implemented. To view the behavior of the proposed system, message sequence charts and state transition diagrams have been

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.670-675
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• 2006

이야기는 그 자체만으로 전달될 수 없기 때문에, 이야기만큼이나 중요한 것은 가공되지 않은 상태의 이야기를 구성지게 전달하는 텔링의 방식이다. 디지털 매체가 발전하고 보다 다양한 전달 방식이 등장하면서 텔링이 더욱 강조되고 이야기보다는 스토리텔링이라는 개념이 주목 받게 되었다. 이 연구는 스토리와 텔링을 구분하는 관점에서, 스토리텔링을 개발하는 작가들의 작업을 분석하고 그들을 도와주는 지원 시스템을 설계했다. 작가의 태스크를 분석하기 위해 본 연구에서는 집필 프로세스에 대해 현업 작가를 인터뷰하고 기존의 writing tool의 기능과 이야기 구조 이론을 참고하여 검토했다. 또한 본 연구에서는 이야기가 흘러감에 따라 변화하는 정보-인물 간 관계, 사실 정보-들을 고려하였다. 작가는 이야기가 흘러가는 매 순간 모든 이야기 속의 사실을 알고 있지만, 독자와 이야기 속의 등장 인물들은 이야기가 흘러감에 따라 작가가 의도하는 순서와 방식으로 사실 정보들을 하나씩 습득하게 된다. 이러한 데이터를 수집/관리하고, 다시 변형하고, 또 유지/보수하는 것이 작가에게 가장 큰 인지적인 부담이기 때문에 이를 지원하도록 노력했다.

• Journal of Information Processing Systems
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• v.15 no.2
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• pp.399-409
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• 2019

Three-dimensional (3D) human pose reconstruction from single-view image is a difficult and challenging topic. Existing approaches mostly process frame-by-frame independently while inter-frames are highly correlated in a sequence. In contrast, we introduce a novel spatial-temporal 3D human pose reconstruction framework that leverages both intra and inter-frame relationships in consecutive 2D pose sequences. Orthogonal matching pursuit (OMP) algorithm, pre-trained pose-angle limits and temporal models have been implemented. Several quantitative comparisons between our proposed framework and recent works have been studied on CMU motion capture dataset and Vietnamese traditional dance sequences. Our framework outperforms others by 10% lower of Euclidean reconstruction error and more robust against Gaussian noise. Additionally, it is also important to mention that our reconstructed 3D pose sequences are more natural and smoother than others.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.352-355
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• 2011

본 논문에서는 깊이 맵의 재배열 과정을 통해서, 보다 개선된 영상을 합성하는 방법을 제안한다. 제안하는 방법은 전체 깊이 맵을 여러 그룹(Group)으로 나누고, 각각의 그룹에 서로 다른 가중치를 주어 가까운 물체에 좀 더 많은 깊이 값을 가질수 있도록 조절하였다. 깊이 맵 추정(Depth Estimation) 및 중간 시점 영상의 합성(View Synthesis)을 통하여 기존 방식과의 비교를 진행하였고 그 결과, 전체적인 비디오 시퀀스(Video Sequence)에 대한 PSNR은 유지하면서, 보다 시각적으로 자연스러운 영상을 얻을 수 있었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.295-296
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• 2020

3DoF+ 비디오 부호화 표준을 개발하고 있는 MPEG-I 비주얼 그룹은 표준화 과정에서 참조 SW 코덱인 TMIV(Test Model for Immersive Video)를 개발하고 있다. TMIV 는 제한된 공간에서 동시에 여러 위치에서 획득한 뷰(view)의 텍스처(texture) 비디오와 깊이(depth) 비디오를 효율적으로 압축하여 임의 시점의 뷰 렌더링(rendering)을 제공한다. TMIV 에서 수행되는 깊이 비디오의 비트 심도 스케일링 및 압축은 깊이 정보의 손실을 발생하며 이는 렌더링(rendering)된 임의 시점 비디오의 화질 저하를 야기한다. 본 논문에서는 보다 효율적인 깊이 비디오 압축을 위한 히스토그램 등화(histogram equalization) 기반의 구간별(piece-wise) 깊이 매핑 기법을 제안한다. 실험결과 제안기법은 자연 영상(natural sequence)의 End-to-End 부호화 성능에서 평균적으로 3.1%의 비트율 절감이 있음을 확인하였다.

• ETRI Journal
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• v.32 no.4
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• pp.622-625
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• 2010

In this letter, we assess the scalability of a path computation flooding (PCF) approach to compute optimal end-to-end inter-domain paths in a path computation element-based multi-domain network. PCF yields a drastically reduced network blocking probability compared to a blind per-domain path computation but introduces significant network control overhead and path computation complexity. In view of this, we introduce and compare an alternative low overhead PCF (LoPCF) solution. From the obtained results, LoPCF leads to similar blocking probabilities to PCF while exhibiting around 50% path computation complexity and network control overhead reduction.

• The KIPS Transactions:PartD
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• v.12D no.3 s.99
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• pp.345-354
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• 2005

Subsequence matching is one of the most important operations in the field of data mining. The existing subsequence matching algorithms use only one index, and their performance gets worse as the difference between the length of a query sequence and the site of windows, which are subsequences of a same length extracted from data sequences to construct the index, increases. In this paper, we propose a new subsequence matching method based on index interpolation to overcome such a problem. An index interpolation method constructs two or more indexes, and performs search ing by selecting the most appropriate index among them according to the given query sequence length. In this paper, we first examine the performance trend with the difference between the query sequence length and the window size through preliminary experiments, and formulate a search cost model that reflects the distribution of query sequence lengths in the view point of the physical database design. Next, we propose a new subsequence matching method based on the index interpolation to improve search performance. We also present an algorithm based on the search cost formula mentioned above to construct optimal indexes to get better search performance. Finally, we verify the superiority of the proposed method through a series of experiments using real and synthesized data sets.