• Annual Conference on Human and Language Technology
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• 1992.10a
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• pp.515-523
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• 1992

일반적으로 한글 인식 과정은 많은 후보들을 생성하며 이 후보들로부터 정확한 인식결과를 얻고 복잡도를 줄이기 위해서는 효과적인 한글 표현과 탐색기법이 요구된다. 이런 목적을 위하여 본 논문에서는 한글에 적합한 구조적 정보들을 4단계 계층적 형태로 표현한다. 그리고 이 정보들을 근거로 후보 문자의 생성과 탐색을 진행하며 전체적으로 최적우선탐색을 이룬다. 인식실험은 다양한 필자들을 대상으로 한글 잦기 상위 422자로 실험한 결과 평균 86% 인식률을 얻을 수 있었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.172-173
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• 2013

최근 표준화가 완료된 HEVO(High Efficiency Video Coding)에서는 계층적 구조를 갖는 가변블록의 크기를 사용하고 재귀적으로 부호화를 수행사여, 최적의 부호화단위(CU: Coding Unit) 분할 구조와 예측단위(PU: Prediction Unit)를 결정함으로써 높은 부호화 효율을 얻을 수 있는 반면 부호화 복잡도가 증가하는 문제가 있다. 본 논문에서는 부호화기의 복잡도를 감소시키기 위한 고속 부호화 알고리즘으로 고속 모드 결정 기법을 제안한다. 제안기법은 상위 깊이(CU: Coding Unit)의 최적 모드와 부호화 율-왜곡 비용을 이용해서 현재 깊이 CU에서의 특정 모드의 율-왜곡 비용 계산을 생략함으로써 PU 탐색을 조기 종료한다. 즉, 상위 깊이 CU의 조건에 따라 화면간 예측 모드의 일부 또는 화면내 예측을 수행하지 않는다. 실험결과 제안기법은 HM 12.0대비 0.2%의 비트 증가에 22.9%의 계산시간 감소 효과를 얻을 수 있음을 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.568-576
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• 2003

This paper proposes a moving object tracking algorithm by using hierarchical search method in dynamic scenes. Proposed algorithm is based on two main steps: generation step of initial model from different pictures, and tracking step of moving object under the time-yawing scenes. With a series of this procedure, tracking process is not only stable under far distance circumstance with respect to the previous frame but also reliable under shape variation from the 3-dimensional(3D) motion and camera sway, and consequently, by correcting position of moving object, tracking time is relatively reduced. Partial Hausdorff distance is also utilized as an estimation function to determine the similarity between model and moving object. In order to testify the performance of proposed method, the extraction and tracking performance have tested using some kinds of moving car in dynamic scenes. Experimental results showed that the proposed algorithm provides higher performance. Namely, matching order is 28.21 times on average, and considering the processing time per frame, it is 53.21ms/frame. Computation result between the tracking position and that of currently real with respect to the root-mean-square(rms) is 1.148. In the occasion of different vehicle in terms of size, color and shape, tracking performance is 98.66%. In such case as background-dependence due to the analogy to road is 95.33%, and total average is 97%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3C
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• pp.279-287
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• 2009

In this paper, a hierarchical stereo matching with color information is proposed. To generate an initial disparity map, feature based stereo matching is carried out and to generate a final disparity map, hierarchical stereo matching is carried out. The boundary (edge) region is obtained by segmenting a given image into R, G, B and White components. From the obtained boundary, disparity is extracted. The initial disparity map is generated when the extracted disparity is spread to the surrounding regions by evaluating autocorrelation from each color region. The initial disparity map is used as an initial value for generating the final disparity map. The final disparity map is generated from each color region by changing the size of a block and the search range. 4 test images that are provided by Middlebury stereo vision are used to evaluate the performance of the proposed algorithm objectively. The experiment results show better performance compared to the Graph-cuts and Dynamic Programming methods. In the final disparity map, about 11% of the disparities for the entire image were inaccurate. It was verified that the boundary for the non-contiguous point was clear in the disparity map.

• Journal of Internet Computing and Services
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• v.11 no.1
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• pp.15-20
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• 2010

In this paper, we propose a novel approach to reduce spatial query access latency and energy consumption by leveraging results from nearby peers in wireless broadcast environments. We propose a three-tier Hierarchical Location-Based Sequential access index, called HLBS, which provides selective tuning (pruning and searching entries) without pointers using a linear accessing structure based on the location of each data object. The HLBS saves search cost and index overhead, since the small index size with a sequential index structure results in low access latency overhead and facilitates efficient searches for sequential-access media (wireless channels with data broadcast). Comprehensive experiments illustrate that the proposed scheme is more efficient than the previous techniques in terms of energy consumption.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.1
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• pp.49-55
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• 2007

To improved the multi-resolution fast hierarchical motion estimation by using de-interlacing algorithm that is effective in term of both performance and VLSI implementation, is proposed so as to cover large search area field-based as well as frame based image processing in SoC design. In this paper, we have simulated a various picture mode M=2 or M=3. As a results, the proposed algorithm achieved the motion estimation performance PSNR compare with the full search block matching algorithm, the average performance degradation reached to -0.7dB, which did not affect on the subjective quality of reconstructed images at all. And acquiring the more desirable to adopt design SoC for the fast hierarchical motion estimation, we exploit foreground and background search algorithm (FBSA) base on the dual arithmetic processor element(DAPE). It is possible to estimate the large search area motion displacement using a half of number PE in general operation methods. And the proposed architecture of MHME improve the VLSI design hardware through the proposed FBSA structure with DAPE to remove the local memory. The proposed FBSA which use bit array processing in search area can improve structure as like multiple processor array unit(MPAU).

• Journal of KIISE:Databases
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• v.28 no.2
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• pp.181-187
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• 2001

디지털 비디오의 사용이 일반화되어감에 따라 비디오 브라우징에 대한 연구가 더욱 요구되 어 지고 있다. 과거에 연구된 바 있는 VCR식 순차탐색기법은 아날로그 비디오 브라우징에 서 사용되던 고전적 방식을 다지털 비디오에 적용한 것이며, 키프레임 정적표현법은 비디오 를 구성하는 프레임을 보이는 방식이다. 이 두 방식이 디지털 비디오의 특성을 충분히 사용 하지 못하기 때문에, 최근에는 비디오 샷산의 계층적 관계를 기반으로 하는 계층적 브라우 징과 장면 간의 관계를 기반으로 하는 장면 기반 브라우징이 주목을 받고 있다. 본 논문에 서는 기존의 비디오 브라우징에 대한 연구들을 자세히 알아보고, 계층적 브라우징과 장면 기반 브라우징에서처럼 비디오 내의 각 장면에 바로 접근할 수 있을 뿐만 아니라, 계층적 브라우징처럼 비디오의 전체구조를 알기 쉽게 보여준다. 또한 브라우징의 결과는 시각적 요 약으로 사용될 수 있다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.657-660
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• 2000

최근 재사용성에 근간을 둔 컴포넌트 기반 소프트웨어(Component-Based Software : CBS) 기술의 실현에 따라 이와 관련된 유지보수 의사결정의 내용도 변화하여 새로운 연구 과제로 등장하고 있다. 이에 본 연구는 컴포넌트 기반 소프트웨어 유지보수와 관련된 의사결정의 이론적 근거를 탐색하고 컴포넌트 평가 및 선택을 위한 모형 개발을 목적으로 한다. 모형 설계에는 평가 기준의 체계를 수립하고 적절한 평가 기법의 선택 및 적용이 포함된다. 평가 기준 구성을 위하여 CBS 유지보수의 특성을 고려한 다차원적 접근법에 의한 계층적 체계화를 시도하였으며, 일부 상호 종속적 관계를 나타내는 요소들에 대하여는 네트워크 관계를 나타내는 모듈로 포함시켰다. 체계화된 평가 기준에 따른 의사결정 대안의 평가 기법으로 주관적 판단의 계량화에 적절하다고 판단되는 계층분석과정(Analytic Hierarchy Process) 기법 및 네트워크분석과정(Analytic Network Process) 기법을 선정하고 적절한 예를 들어 모형 적용의 이해를 돕고자 하였다.

• Journal of the Korean Society for information Management
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• v.26 no.2
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• pp.173-194
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• 2009

Recently, semantic search techniques which are based on information space as consisting of nonambiguous, non-redundant, formal pieces of ontological knowledge have been developed so that users do exploit large knowledge bases. The purpose of the study is to design more user-friendly and smarter retrieval interface based on ontological analysis, which can provide more precise information by reducing semantic ambiguity or more rich linked information based on well-defined relationships. Therefore, this study, first of all, focuses on ontological analysis on researcher information as selecting descriptive elements, defining classes and properties of descriptive elements, and identifying relationships between the properties and their restriction between relationships. Next, the study designs the prototypical retrieval interface based on ontology-based representation, which supports to semantic searching and browsing regarding researchers as a full-fledged domain. On the proposed retrieval interface, users can search various facts for researcher information such as research outputs or the personal information, or carrier history and browse the social connection of the researchers such as researcher group that is lecturing or researching on the same subject or involving in the same intellectual communication.

• Journal of Korea Multimedia Society
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• v.17 no.3
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• pp.333-341
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• 2014

Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. Multi-view video coding requires high computational complexity. To reduce computational complexity and maintain the image quality, an effective early termination motion estimation method is proposed in this paper. The proposed method exploiting the characteristic of motion vector distribution uses a hierarchical search strategy. This strategy method consists of multi-grid square search pattern, modified diamond search pattern, small diamond search pattern and raster search pattern. Experiment results show that the speedup improvement of the proposed method over TZ search method and FS(Full Search) method JMVC (Joint Multiview Video Coding) can be up to 1.7~4.5 times and 90 times faster respectively while maintaining similar video quality and bit rates.