• Journal of KIISE:Databases
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• v.34 no.5
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• pp.420-436
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• 2007

The choice of an effective indexing method is crucial to guarantee the performance of the spatial join operator which is heavily used in geographical information systems. The $R^*$-tree based method is renowned as one of the most representative indexing methods. In this paper, we propose an efficient spatial join technique based on the DOT(Double Transformation) index, and compare it with the spatial Join technique based on the $R^*$-tree index. The DOT index transforms the MBR of an spatial object into a single numeric value using a space filling curve, and builds the $B^+$-tree from a set of numeric values transformed as such. The DOT index is possible to be employed as a primary index for spatial objects. The proposed spatial join technique exploits the regularities in the moving patterns of space filling curves to divide a query region into a set of maximal sub-regions within which space filling curves traverse without interruption. Such division reduces the number of spatial transformations required to perform the spatial join and thus improves the performance of join processing. The experiments with the data sets of various distributions and sizes revealed that the proposed join technique is up to three times faster than the spatial join method based on the $R^*$-tree index.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.364-370
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• 2014

The management and analysis of spatio-temporal and multimedia data is a hot issue in database research because such data types are handled in manny applications. Querying databases of such a content is very important for these applications. This paper addresses algorithms that make index structure by using Douglas-Peucker Algorithm and process range query efficiently on moving objects trajectories. We compare and analyze our algorithms and MBR by experiments. Our algorithms make smaller size of index structure and process more efficiently.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.507-510
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• 1998

다양한 분야에서 중요하게 사용될 수 있는 뉴스 비디오 데이터베이스를 구축하기 위해서는 비디오 색인의 자동화에 관한 연구가 필연적이다. 본 논문에서는 뉴스 비디오 색인을 자동화하는 방법으로, 이전에 제안한 컷 추출 방법을 이용하였다. 컷에 의해 추출된 키 프레임에서 앵커 인식 알고리즘으로 앵커 프레임을 자동으로 추출하여 색인을 부여하는 방법으로 비디오 스트림에 대한 색인을 자동화하였다. 구성되는 색인 구조의 형태는 앵커 프레임들이 시간에 따른 사건의 연결이 되고, 앵커 프레임 내에서는 종속되는 키 프레임들을 중심으로 원형을 형성한다. 이들 각각을 논리적으로 통합하면 사용자의 관점에 따라 여러 가지 방법으로 브라우징되며, 사용자가 원하는 뉴스 비디오 씬들을 쉽게 선택하여 볼 수 있는 특징을 제공하는 장점을 부여한다. 또한, 색인화 된 비디오 스트림을 이용하면 자동적으로 비디오 편집을 수행 할 수 있는 비디오 저작도구의 기반을 제공할 수 있다.

• Journal of the Korea Society of Computer and Information
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• v.14 no.6
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• pp.65-71
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• 2009

The basic features in the indexing and retrieval of the image is used color, shape, and texture in traditional image retrieval method. We do not use these features and offers a new way. For content-based video indexing and retrieval, visual features used to measure the similarity of the geometric method is presented. This method is called the Radon transform. Without separation, this method is calculated based on the geometric distribution of image. In the experiment has a very good search results.

• Journal of KIISE:Databases
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• v.33 no.1
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• pp.1-11
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• 2006

It is possible to track the moving vehicle as well as to develop the location based services actively according to the progress of wireless telecommunication and GPS, to the spread of network, and to the miniaturization of cellular phone. To provide these location based services, it is necessary for an index technique to store and search too much moving object data rapidly. However the existing indices require a lot of costs to insert the data because they store every position data into the index directly. To solve this problem in this paper, we propose a buffer node operation and design a GU-tree(Group Update tree). The proposed buffer node method reduces the input cost effectively since the operation stores the moving object location data in a group, the buffer node as the unit of a non-leaf node. hnd then we confirm the effect of the buffer node operation which reduces the insert cost and increase the search performance in a time slice query from the experiment to compare the operation with some existing indices. The proposed tufter node operation would be useful in the environment to update locations frequently such as a transportation vehicle management and a tour-guide system.

• The KIPS Transactions:PartD
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• v.10D no.3
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• pp.501-512
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• 2003

This paper proposes an indexing technique for fast retrieval of similar image subsequences using the multi-dimensional time warping distance. The time warping distance is a more suitable similarity measure than Lp distance in many applications where sequences may be of different lengths and/or different sampling rates. Our indexing scheme employs a disk-based suffix tree as an index structure and uses a lower-bound distance function to filter out dissimilar subsequences without false dismissals. It applies the normaliration for an easier control of relative weighting of feature dimensions and the discretization to compress the index tree. Experiments on medical and synthetic image sequences verify that the proposed method significantly outperforms the naive method and scales well in a large volume of image sequence databases.

• The KIPS Transactions:PartB
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• v.9B no.5
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• pp.689-700
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• 2002

In this paper, we developed Korean Morphological Analyzer for an automatic indexing that is essential for Information Retrieval. Since it is important to index large-scaled document set efficiently, we concentrated on maximizing the speed of word analysis, modularization and structuralization of the system without new concepts or ideas. In this respect, our system is characterized in terms of software engineering aspect to be used in real world rather than theoretical issues. First, a dictionary of words was structured. Then modules that analyze substantive words and inflected words were introduced. Furthermore numeral analyzer was developed. And we introduced an unknown word analyzer using the patterns of morpheme. This whole system was integrated into K-2000, an information retrieval system.

• Spatial Information Research
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• v.10 no.1
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• pp.61-76
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• 2002

Mobile map services using PDA are prevailing because of the rapid developments of techniques of the internet and handhold devices recently. While the volume of spatial data is tremendous and the spatial operations are time-intensive, the PDA has small size memory and a low performance processor. Therefore, the spatial index for PDA should be small size and efficiently filter out the candidate objects of spatial operation as well. This paper proposes a spatial index far PDA called MHF(Multilevel Hashing File). The MHF has simple structure for storage efficiency and uses a hashing technique, which is direct search method, for search efficiency. This paper also designs a compression technique for MBR. which occupies almost 80% of index data in the two dimensional case. We call it HMBR. Although the HMBR technique reduces the MB\ulcorner size to almost a third, it shows good filtering efficiency because of no information loss by quantization in case of small objects that occupy a major portion. Our experimental tests show that the proposed MHF index using HMBR technique is appropriate for PDA in terms of the size of index, the Number of MBR comparisons, the filtering efficiency and the execution time of spatial operations.

• Journal of Information Management
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• v.39 no.4
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• pp.121-154
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• 2008

In this paper, a ontology-based keyword structuring method is proposed to represent the knowledge structure of scholarly documents and to make inferences from the semantic relationships holding among them. The characteristics of thesaurus as a knowledge organization system(KOS) for subject heading is critically reviewed from the information retrieval point of view. The domain concepts are identified and classified by analysis of the information activities occurring in a general research process based on scholarly sensemaking model. The ontological structure of keyword set is defined in terms of the semantic relationship of the canonical concepts which constitute scholarly documents such as journal articles. As a result, each ontologically structured keyword set of a document represents the knowledge structure of the corresponding document as semantic index. By means of the axioms and inference rules defined for information needs, users can efficiently explore the scholarly communication network built on the semantic relationship among documents in an analytic way based on the scholarly sensemaking model in oder to efficiently retrieve the relevant information for problem solving.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06c
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• pp.55-57
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• 2006

최근 XML 문서가 인터넷 기반의 애플리케이션 간의 자료 저장 및 교환을 위한 표준으로써 부상함에 따라 XML 문서의 저장 및 관리에 대한 연구가 활발히 이루어지고 있다. 하지만 XML 문서의 검색에 관련된 많은 연구들이 모든 XML 엘리먼트 경로에 대한 색인화로 인해 인덱스의 크기가 커지고 이에 비례하여 검색성능이 뜯어지는 문제를 보이고 있다. 본 논문에서는 이를 개선하기 위해 엘리먼트 타일을 기반으로 전통적인 역색인 방법을 XML 문서에 맞게 확장하고, RDBMS에 기반하여 계층구조를 갖는 XML 문서들의 자료를 구조적 넘버링(Numbering) 방법의 인덱스로 설계 하였다. 인덱스 테이블들은 엘리먼트 타입의 정보를 담고 있는 엘리먼트 타입 테이블, XML문서의 경로를 가지고 있는 경로 테이블, 역색인으로 구성된 Term테이블. Term 경로를 나타내는 Term경로 테이블을 생성한다. 이전의 XML 인덱싱 기법에 관련된 연구들에서 보이는 XML 문서상의 모든 경로에 대한 표현을 간소화 시키고, 이를 통해 보다 좋은 검색 성능을 보이고자 하였다.