• Journal of Korea Multimedia Society
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• v.13 no.7
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• pp.991-999
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• 2010

In this paper, we propose a fast motion estimation algorithm for video encoding. Conventional fast motion estimation algorithms have a serious problem of low prediction quality in some frames. However, full search based fast algorithms have low computational reduction ratio. In the paper, we propose an algorithm that significantly reduces unnecessary computations, while keeping prediction quality almost similar to that of the full search. The proposed algorithm uses distribution probability of motion vectors and adaptive search patterns and block matching criteria. By taking different search patterns and error criteria of block matching according to distribution probability of motion vectors, we can reduces only unnecessary computations efficiently. Our algorithm takes only 20~30% in computational amount and has decreased prediction quality about 0~0.02dB compared with the fast full search of the H.264 reference software. Our algorithm will be useful to real-time video coding applications using MPEG-2 or MPEG-4 AVC standards.

• Journal of Korea Multimedia Society
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• v.16 no.5
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• pp.539-548
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• 2013

Although Motion estimation (ME) plays an important role in digital video compression, it requires a complicated search procedure to find an optimal motion vector. Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. The computational complexity of motion estimation for Multi-view video coding increases in proportion to the number of cameras. To reduce computational complexity and maintain the image quality, a low complexity motion estimation search method is proposed in this paper. The proposed search method consists of four-grid diamond search patten, two-gird diamond search pattern and TZ 2 Point search pattern. These search patterns exploit the characteristics of the distribution of motion vectors to place the search points. Experiment results show that the speedup improvement of the proposed method over TZ search method (JMVC) can be up to 1.8~4.5 times faster by reducing the computational complexity and the image quality degradation is about to 0.01~0.24 (dB).

• Korean Journal of Culture and Social Issue
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• v.16 no.3
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• pp.289-310
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• 2010

The purpose of this study was to examine how political interest, political ideologies, and information-searching goals influence the amount of information voters search, the ways in which people search for information about political candidates, and the type of information they select. The results showed that the participants under accuracy goal searched much more information and the participants under the high level of interest were not affected by conservative ideology, but the participants with the low level of interest were influenced by the liberal ideology and viewed substantially more information. And most of participants had the attribute-centered searching pattern. The social policies were accessed most, however, the information about party and personal background of a candidate were found least.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.329-336
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• 2017

In video compression, Motion Estimation(ME) limits the performance of image quality and generated bit rates. However, it requires much complexity in the encoder part. Multi-view video uses many cameras at different positions. Multi-view video coding needs huge computational complexity in proportion to the number of the cameras. To reduce computational complexity and maintain the image quality, an effective motion estimation method is proposed in this paper. The proposed method exploiting the characteristics of motion vector distribution and the motion of video. The proposed is a kind of a hierarchical search strategy. This strategy consists of multi-grid rhombus pattern, diagonal pattern, rectangle pattern, and refinement pattern. Experiment results show that the complexity reduction of the proposed method over TZ search method and PBS (Pel Block Search) on JMVC (Joint Multiview Video Coding) can be up to 40~75% and 98% respectively while maintaining similar video image quality and generated bit rates.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.97-100
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• 2004

인터넷상에서 존재하는 많은 데이터베이스들 중 현실적으로 유용한 정보를 가지고 있는 것은 텍스트 데이타베이스이다. 텍스트 마이닝 기법에서 비구조적인 특징을 가진 텍스트 데이타로부터 유용한 정보를 분석하고 추출하여 연관된 패턴을 탐색하는 과정은 중요한 연구과제이다. 이에 본 논문은 인터넷에서 저장된 텍스트 데이터를 가지고 기존 텍스트 마이닝 기법 중 연관탐색 기법을 적용하여 사용자 중심의 연관된 패턴을 찾아서 의미있는 정보를 얻고자 한다. 탐색하기 위해 먼저 전처리 작업으로 용어의 객체를 추출하고. 추출된 각 객체들은 대용량 데이터에서 시간적, 공간적면에서 효율적인 연관탐색 기법인 NFP-Algorithm(N-most interesting k-itemsets Using FP-tree and FP-Growth)을 적용시켜서 의미있는 정보를 추출했다. 또한 Apriori계 Algorithm, FP-Algorithm, NFP-Algorithm을 비교하여 NFP-Algorithm이 시간적면에서 효율적임을 보여주었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.326-329
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• 2021

데이터베이스에서의 빈발 패턴 탐색은 일정 횟수 이상 같이 등장하는 항목들의 집합을 찾는 문제이다. 본 논문은 다수의 2 차원 배열들이 주어졌을 때, 이들 내부에서 빈번히 같이 등장하는 부분 구역들을 찾는 문제를 다룬다. 하지만 기존 빈발 패턴 탐색 기법들은 배열 내 원소들의 위치 관계까지 고려하지는 않기 때문에 본 문제에 바로 적용하기는 어렵다. 따라서 본 논문은 다수의 2 차원 배열 내에서 빈번히 같이 발생하는 부분 구역들을 효율적으로 찾는 기법을 제안한다. 본 논문의 선행 연구에서는 주어진 배열들을 두 번 스캔하여 빈발 부분 구역 집합을 찾는 기법을 제안하였다. 본 논문에서는 이를 개선하여 배열들을 한 번만 스캔하고도 빈발 부분 구역 집합을 찾는 효율적인 기법을 제안한다. 이를 위해 제안 방법은 지금까지 탐색된 부분 구역들에 대한 정보를 메모리에 효율적으로 유지한다. 실험결과 제안방법은 기존 방법에 비해 수행시간을 약 30% 단축함을 보였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.625-630
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• 2009

In this paper, we introduce the analysis and counter-measure of signal distortion of search radar equipped on the ship. Using ShipEDF program, the search radar's main antenna and ship structures are modeled in the view of electromagnetism. Ray tracing method is used for analysis of the search radar's radiation patterns in free space and ship condition. From analyzed radiation patterns, we can conclude that the search radar's signal distortion is due to radiation pattern distortion. We also analyze the surface current distribution of the mast to propose the counter-measure to reduce electro-magnetic field reflection of mast.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.331-334
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• 2011

입력 데이터의 공통적인 특징을 찾아내는 방법은 기계 학습 분야의 중요한 분야이다. 일반적으로 입력 데이터의 형태적 패턴을 찾아내는 알고리즘들이 많이 연구되었는데, 최근에는 데이터의 입력 순서 또는 데이터 사이의 시간적 인과 관계와 같이 시간에 연관된 패턴을 찾는 방법이 주목을 받고 있다. 우리는 형태적 혹은 공간적 패턴 탐색에 뛰어난 성능을 보이는 하이퍼네트워크 모델을 확장하여 입력 데이터의 시공간적 패턴을 찾는 방법을 제시한다. 하이퍼네트워크는 두 개 이상의 변수를 하나의 엣지로 연결하여 문제공간을 탐색하는 모델로, 시간과 공간의 변수를 동시에 고려하여 데이터의 특성을 찾아내는 데에 적합하다. 이를 확인하기 위하여 사람의 EEG 신호를 분석하였는데, 시각적인 정보를 처리할 때와 언어적 정보를 처리할 때의 특징적인 패턴들을 찾았다.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.5
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• pp.255-259
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• 2005

To search a pattern P in a text, such index data structures as suffix trees and suffix arrays are widely used in diverse applications of string processing and computational biology. It is well known that searching in suffix trees is faster than suffix ways in the aspect of time complexity, i.e., it takes O(${\mid}P{\mid}$) time to search P on a constant-size alphabet in a suffix tree while it takes O(${\mid}P{\mid}+logn$) time in a suffix way where n is the length of the text. In this paper we present a linear-tim8 search algorithm in suffix arrays for constant-size alphabets. For a gene.al alphabet $\Sigma$, it takes O(${\mid}P{\mid}log{\mid}{\Sigma}{\mid}$) time.

• Journal of KIISE:Software and Applications
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• v.30 no.5_6
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• pp.487-496
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• 2003

The promoter that plays a very important role in gene expression as a signal part has various binding sites for transcription factors. These binding sites are located on various parts in promoter region and have highly conserved consensus sequence patterns. This paper presents a new method for the consensus pattern search in promoter regions using genetic algorithm, which adopts the assumption of N-occurrence-per-dataset model of MEME algorithm and employs the advantage of Wataru method in determining the pattern length. Our method will be employed by genome researchers who try to predict the promoter region on anonymous DNA sequence and to find out the binding site for a specific transcription factor.