• 한국공간정보시스템학회:학술대회논문집
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• 2003.11a
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• pp.159-162
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• 2003

In this paper, to find probable collision positions between moving object and terrain in 3D space efficiently, we use a model, similar to Ray Tracing, which finds the triangles intersected by a directed line segment from a large amount of triangles. We try to reduce dead space as much as possible to find candidate triangles intersected by a directed line segment than previous work's. A new modified octree, LBV-Octree(Least Bounding Voxel Octree), is proposed, and we have a ray tracing with it. In the experiment, ray tracing with LBV-Octree provides $5%{\sim}11%$ better performance than with classical octree.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.397-400
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• 2006

본 논문에서는 위치기반 서비스에서 도로 네트워크 상을 움직이는 객체들의 현재 위치를 효율적으로 갱신하는 색인기법을 제안한다. 효율적인 시공간 질의 처리를 위하여 도로를 적절하게 분할하여 색인하게 된다. 기존의 도로 분할 방식은 연결정보를 포함하지 않기 때문에 객체가 현재의 도로 영역을 벗어났을 때 색인구조를 처음부터 검색해야 하는 단점이 있다. 제안하는 기법은 도로를 분할할 때 교차점을 포함하도록 분할하여 연결 정보가 유지되도록 한다. 이로 인해 제안하는 알고리즘은 객체가 색인된 현재의 도로 영역을 벗어났을 때 연결 정보와 NN(Nearest Neighbor) 검색 기법을 이용하여 벗어난 도로를 바로 찾아갈 수 있으므로 향상된 갱신 성능을 보인다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.649-651
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• 2001

본 논문에서는 XML 문서의 효율적인 관리와 구조검색을 위한 구조적 색인 방법을 제안한다. 기존의 방법은 특정 엘리먼트의 부모, 자식, 형제애 대한 다양한 구조검색을 효율적으로 지원하지 못하므로, XML 문서의 구조정보를 LETID(Labeled Element Type ID)로 표현하며 엘리먼트를 식별하고, 부모와 자식 엘리먼트간의 계층 정보와 동일한 부모 엘리먼트를 갖는 자식 엘리먼트들의 순서정보를 나타낸다. LETID는 고정된 크기로 하며, 엘리먼트에 고유 ID를 부여하는 방식을 통해서 DTD의 논리적 구조를 분석할 때 부모 형제 노드를 직접적으로 찾을 수 있고 ID 값에 깊이정보가 포함되어 있기 때문에 고유번호만 보고 깊이를 알 수가 있다. 이 구조정보를 이용하여 빠른 검색을 위한 내용 색인 구조 색인 애트리뷰트 색인을 설계하고 설계된 색인을 통하여 질의를 처리하여 다양한 구조적 질의를 효율적으로 처리할 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06c
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• pp.16-21
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• 2010

잠재 의미를 색인하는 것은 문서 색인에 있어서 그 색인 품질에 주요한 요인을 차지한다. 본 논문에서 살펴보는 의미 확산 방법은 문서 집합에 나타나는 단어들의 의미적 연관성을 바탕으로 활성화 작용 모델(spreading activation model)을 구축하고 색인 대상 문서의 단어 분포를 출발점으로 삼아, 그 모델 안에서 의미적으로 수렴할 수 있도록 랜덤 워크 방법(random walk method)1)을 수정한 변형 방법을 이용해 확률을 확산시킨다. 이 방법은 단어 사이의 연관성을 따라 탐색하며 동의어와 다의어 등 단순 단어 일치로는 알 수 없는 의미적 유사 단어들이 의미 있는 확률 분포를 갖게 한다. 이는 단어들의 의미 분포를 가중치 그래프를 통해 보다 합리적으로 다루게 된다. 실험에서는 문서 분류를 시행하여 평균 정확도 및 정확도-재현율 곡선을 산출하였고, 비교 실험을 통해서 전반적인 우수성을 관찰할 수 있었다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.2
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• pp.95-102
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• 2011

In this paper, a Mobile Continuous Query Processing System (MCQPS) is designed to solve problems related to database hoarding, maintenance of shared data consistency, and optimization of logging. These problems are caused by weak connectivity and disconnection of wireless networks inherent in mobile database systems under mobile client-server environments. We show the superiority of the proposed MCQPS by comparing its performance to the Client-Intercept-Server (C-I-S) model. In addition, several experimental results show the effectiveness of our proposed indexing structure and methodology for real-time continuous queries.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.834-837
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• 2009

There is a growing need for ad-hoc analysis of extremely large data sets, especially at e-Commerce companies which depend on recommender application. Nowadays, as the number of e-Commerce web pages grow to a tremendous proportion; vertical recommender services can help customers to find what they need. Recommender application is one of the reasons for e-Commerce success in today's world. Compared with general e-Commerce recommender application, obviously, general e-Commerce recommender application's processing scope is greatly narrowed down. MapReduce is emerging as an important programming model for large-scale data-parallel applications such as web indexing, data mining, and scientific simulation. The objective of this paper is to explore MapReduce framework for the e-Commerce recommender application on major general and dedicated link analysis for e-Commerce recommender application, and thus the responding time has been decreased and the recommender application's accuracy has been improved.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.317-320
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• 2009

Dataspaces are the collections of heterogeneous and partially unstructured data. It is difficult for the users to explore the data from varies data sources using a single schema. And the queries supposed should be allowed to specify varying degrees of structure, spanning keyword queries to more structure-aware queries. Utilizing give the model of heterogeneous data and the definitions of two mainly types of query on dataspaces, in this paper we propose an improved method which can suppose the flexibly query more efficiently.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.83-92
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• 1997

Multipath ATM switch architectures have the potential to accommodate easily the design of high-speed and large capacity ATM switches which can handle a very large amount of switching throughputs. However, the multipath architecture inevitably encounters out-of-sequence problems. We propose a multipath switch model to analyze the out-of-sequence phenomenon. And we analyze the out-of-sequence performance dependency on the architecture parameters : the number of multipath, the trunk utilization, the switch size, and the number virtual channels/trunk. Indexing terms : ATM switch, Multipath archltecture, Out-of-sequence performance, Cell sequence integrity, Analytical model.

• The Transactions of the Korea Information Processing Society
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• v.5 no.6
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• pp.1431-1440
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• 1998

Video data are retrieved and stored in various compressed forms according to their characteristics, In this paper, we present a generic data model that captures the structure of a video document and that provides a means for indexing a video stream, Using this model, we design and implement CVIMS (the MPEG-2 Compressed Video Information Management System) to store and retrieve video documents, CVIMS extracts I-frames from MPEG-2 files, selects key-frames from the I -frames, and stores in database the index information such as thumbnails, captions, and picture descriptors of the key-frames, And also, CVIMS retrieves MPEG- 2 video data using the thumbnails of key-frames and v31ious labels of queries.

• Proceedings of the IEEK Conference
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• summer
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• pp.92-96
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• 2004

The researches of the emotions are currently great interest in speech processing as well as in human-machine interaction domain. In the recent years, more and more of researches relating to emotion synthesis or emotion recognition are developed for the different purposes. Each approach uses its methods and its various parameters measured on the speech signal. In this paper, we proposed using a short-time parameter: MFCC coefficients (Mel­Frequency Cepstrum Coefficients) and a simple but efficient classifying method: Vector Quantification (VQ) for speaker-dependent emotion recognition. Many other features: energy, pitch, zero crossing, phonetic rate, LPC... and their derivatives are also tested and combined with MFCC coefficients in order to find the best combination. The other models: GMM and HMM (Discrete and Continuous Hidden Markov Model) are studied as well in the hope that the usage of continuous distribution and the temporal behaviour of this set of features will improve the quality of emotion recognition. The maximum accuracy recognizing five different emotions exceeds $88\%$ by using only MFCC coefficients with VQ model. This is a simple but efficient approach, the result is even much better than those obtained with the same database in human evaluation by listening and judging without returning permission nor comparison between sentences [8]; And this result is positively comparable with the other approaches.