• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.4
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• pp.50-58
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• 2001

The image information, used most frequently in multimedia, is visual and spatial information. It has several characters including the diversity of storage and output methods, large capacity, spatial relationship expression, and irregularity. Therefore, the various researches for methods of storing efficiently, managing, searching such image data are going on. And recently, it has arisen the movement of international standardization, MPEG-7 for searching contents base in multimedia environment. Especially, the research for implementation of more effective image database searching system important subject, because the practical image search system which can storage a lot of image information as database and query, search them has not generalized. Now the image search system based on text has researched to high degree, but it has many shortages so that nowadays the researches for searching system based on contents are going on. This research has used the wavelet conversion largely using in image processing instead of DCT method largely using in existent system, and so it had met similar and precise results than prior methods by image compression and extraction of specific vector.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.892-896
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• 2003

XML is used in various fields such as interface format for data swapping between application between several various system passing over thing to mark to web browser simply. Accordingly, a lot of studies about system that can manage effectively and search XML document with formation of information, reusability, disposal and durability, portability are proceeding. In this paper, explain about XQL and document structure processor and language processor of quality and make contents of XML document by tree structure, structure information presents method that find XML document tree structure information that is correct on question using XQL while do parsing. Through this, described for design and embodiment of efficient XML document search system that use XQL that compose structure information of document in tree structure and is proposed in language of quality after do parsing absorbing XML document that is scattered on web.

• The KIPS Transactions:PartD
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• v.13D no.2 s.105
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• pp.157-164
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• 2006

Since XML is emerging as the de facto standard for exchanging and representation of data on the web, the amount of XML data has rapidly increased. Thus, the need for effective store and retrieval of U data has arisen. Since the existing techniques such as XRel which is an XML storage and management technique using RDBMS simply record the existing all label paths, diverse classes of label path expressions could not be efficiently supported. In this paper, we present a technique which supports storage and retrieval for XML data using RDBMS efficiently compared with the existing approaches. Since the proposed technique keeps the XML path index on the relational database and replace label paths with path identifiers, diverse XML queries can be evaluated compared with existing approaches. Also, the proposed technique does not require the modification of the relational database engine and consumes the disk space less. Our experimental result demonstrates the better query performance compared with existing techniques.

• Journal of the Korean association of regional geographers
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• v.3 no.2
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• pp.105-120
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• 1997

One of the most important issues of object-oriented geographical database system is to develop an indexing technique which enables more efficient I/O processing within aggregation hierarchy or inheritance hierarchy. Up to present, several indexing schemes have been developed for this purpose. However, they have separately focused on aggregation hierarchy or inheritance hierarchy of object-oriented data model. A recent research is proposing a nested-inherited index which combines these two hierarchies simultaneously. However, this new index has some weak points. It has high storage costs related to its use of auxiliary index. Also, it cannot clearly represent the inheritance relationship among classes within its index structure. To solve these problems, this thesis proposes a pointer-chain index. Using pointer chain directory, this index composes a hierarchy-typed chain to show the hierarchical relationship among classes within inheritance hierarchy. By doing these, it could fetch the OID list of objects to be retrieved more easily than before. In addition, the pointer chain directory structure could accurately recognize target cases and subclasses and deal with "select-all" typed query without collection of schema semantic information. Also, it could avoid the redundant data storing, which usually happens in the process of using auxiliary index. This study evaluates the performance of pointer chain indexing technique by way of simulation method to compare nested-inherited index. According to this simulation, the pointer chain index is proved to be more efficient with regard to storage cost than nested-inherited index. Especially in terms of retrieval operation, it shows efficient performance to that of nested-inherited index.

• Journal of KIISE:Databases
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• v.31 no.2
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• pp.195-204
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• 2004

The Semantic Web is proposed as the next generation Web technology. In the environment of the Semantic Web, resources are related with each other semantically and computers can process this information easily. The Resource Description Framework (RDF) supports this semantic relationship. RDF is the data model for describing metadata of the Web resources. To establish and develop the Semantic Web, methods for managing RDF data efficiently are the most important. So, in this research, we propose methods for storing and querying RDF data using an XML database system. Using an XML database system, XML data, main data of the Semantic Web, and RDF data, the metadata of XML data, can be managed in the same storage and by the same mechanism efficiently. In addition, we propose an efficient data retrieval method and several techniques to improve the system performance. Our query processing technique performs better than an existing system.

• Journal of Digital Contents Society
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• v.15 no.5
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• pp.603-612
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• 2014

To provide efficient and correct search results, ontology which use the structure of information, is considered as a main mechanism in the semantic web. Therefore, recent research in information retrieval and data construction have emphasized the use of ontologies as a data representation and search mechanism. In this paper, we propose a semantic search method using ontology to improve search ability in web environment. Ontology and knowledge base is used to represent semantic meaning of the data and provide related web documents and facts as results. Also, search result ranking mechanism is proposed. The mechanism use cardinality of the keyword in the contents and structural information of ontology. Experimental results with several query processing indicate that different coefficient value in the expression gives different results in sample ontology system and we propose appropriate values of the coefficient.

• Spatial Information Research
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• v.19 no.1
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• pp.107-116
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• 2011

Due to development of environment of wireless Internet, location based services on the basis of spatial data have been increased such as real time traffic information as well as CNS(Car Navigation System) to provide mobile user with route guidance to the destination. However, the current application adopting the file-based system has limitation of managing and storing the huge amount of spatial data. In order to supplement this challenge, research which is capable of managing large amounts of spatial data based on embedded database system is surely demanded. For this reason, this study aims to suggest the lossless compression technique by using the hybrid approach of BytePacking and Lempel-Ziv which can be applicable in DBMS so as to save a mass spatial data efficiently. We apply the proposed compression technique to actual the Seoul and Inchcon metropolitan area and compared the existing method with suggested one using the same data through analyzing the query processing duration until the reconstruction. As a result of comparison, we have come to the conclusion that suggested technique is far more performance on spatial data demanding high location accuracy than the previous techniques.

• The KIPS Transactions:PartD
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• v.12D no.5 s.101
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• pp.789-796
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• 2005

Because existing information retrieval systems, in particular library retrieval systems, use 'exact keyword matching' with user's query, they present user with massive results including irrelevant information. So, a user spends extra effort and time to get the relevant information from the results. Thus, this paper will propose SULRM a Retrieval Model using Subject Classification Table, User profile, and LSI(Latent Semantic Indexing), to provide more relevant results. SULRM uses document filtering technique for classified data and document ranking technique for non-classified data in the results of keyword-based retrieval. Filtering technique uses Subject Classification Table, and ranking technique uses user profile and LSI. And, we have performed experiments on the performance of filtering technique, user profile updating method, and document ranking technique using the results of information retrieval system of our university' digital library system. In case that many documents are retrieved proposed techniques are able to provide user with filtered data and ranked data according to user's subject and preference.

• The KIPS Transactions:PartB
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• v.10B no.1
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• pp.57-66
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• 2003

We propose a technique to extract a relevant passage from text collection based on field-associated terms since they tries to concentrate relevant text to users query. Documents are supposed to be managed as a whole without any segmentation into small pieces, but the method presented is independent upon any text-embedded auxiliary information, and is based on topic continuity and transition. For users needs-relative sentences or passages, we present a passage retrieval techniques by using occurrence frequency of a field-associated term to delimit text, that is likely to be relevant to a particular topic, considering continuity and transition within topic flowing in text. We evaluate 50 Japanese documents and verify the usefulness with 82% for average precision and 63% for recall.

• 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.