• Journal of KIISE:Databases
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• v.35 no.5
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• pp.421-431
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• 2008

Recently XML is becoming a de facto standard for online data exchange between heterogeneous systems and also the research of streaming XML data filtering comes into the spotlight. Since streaming XML data filtering technique needs rapid matching of queries with XML data, it is required that the query processing should be efficiently performed. Until now, most of researches focused only on partial sharing of path expressions or efficient predicate processing and they were work for time and space efficiency. However, if containment relationship between queries is previously calculated and the lowest level query is matched with XML data, we can easily get a result that high level queries can match with the XML data without any other processing. That is, using this containment technique can be another optimal solution for streaming XML data filtering. In this paper, we suggest an efficient XML data filtering based on prime number indexing and containment relationship between queries. Through some experimental results, we present that our suggested method has a better performance than the existing method. All experiments have shown that our method has a more than two times better performance even though each experiment has its own distinct test purpose.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.7
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• pp.680-693
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• 2008

Recent studies on XML filtering assume that all data sources follow a single global schema defined in a filtering system. However, beyond this simple assumption, a filtering system can provide a service that allows data publishers to have their own schema; hence, the data sources will become heterogeneous. The number of data sources is expected to be large in a filtering system and the data sources are frequently published, updated, and disappeared, that is, dynamic. In this paper, we introduce implementing a simple and efficient XPath query translation method for such a dynamic environment. The method is especially targeted for a query which is composed based only on users' knowledge and experience without a graphical guidance of the global schema. When a user queries a large number of heterogeneous data, there is a high possibility that the query is not consistent with the same local schema assumed by the user. Our query translation method also supports a function for this problem. Some experimental results for query translation performance have shown that our method has reasonable performance, and is more practical than the existing method.

• Journal of Information Technology and Architecture
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• v.10 no.1
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• pp.123-135
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• 2013

This paper presents a two-dimensional grouping index(2DG-index) for efficient processing of XML filtering queries. Recently, many index techniques have been suggested for the efficient processing of structural relationships among the elements in the XML database such as an ancestor- descendant and a parent-child relationship. However, these index techniques focus on simple path queries, and don't consider the path queries that include a condition value for filtering. The 2DG-index is an index structure that deals with the problem of clustering index entries in the twodimensional domain space that consists of a XML path identifier domain and a filtering data value domain. For performance evaluation, we have compared our proposed 2DG-index with the conventional one dimensional index structure such as the data grouping index (DG-index) and the path grouping index (PG-index). As the result of the performance evaluations, we have verified that our proposed 2DG-index can efficiently support the query processing in XML databases according to the query types.

• Journal of KIISE:Databases
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• v.34 no.3
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• pp.270-281
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• 2007

Recently, there has been growing interest in streaming XML data. Much of the work on streaming XML data has been focused on efficient filtering of XML data. Such XML filtering systems deliver XML documents to interested users. The burden of extracting the XML fragments of interest from XML documents is placed on users. As a result, several evaluation techniques for streaming XML data, which only extract interested XML fragments by directly evaluating XML queries on streaming XML data, have been proposed. However, existing evaluation techniques for streaming XML data only support the restricted subset of XPath queries, and multiple queries cannot be evaluated by such evaluation techniques. In this paper, we propose XTREAM which evaluates multiple queries in conjunction with the read-once nature of streaming data. In contrast to the previous work, XTREAM supports a wide class of XPath queries including order based predicates and so on. Experimental results with real-life and synthetic XML data demonstrate the efficiency and scalability of XTREAM.

• Journal of KIISE:Databases
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• v.33 no.1
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• pp.138-149
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• 2006

As the environment with sensor network and ubiquitous computing is emerged, there are many demands of handling continuous, fast data such as streaming data. As work about streaming data has begun, work about management of streaming data in Publish-Subscribe system is started. The recent emergence of XML as a standard for information exchange on Internet has led to more interest in Publish - Subscribe system. A filtering technique of streaming XML data in the existing Publish- Subscribe system is using some schemes based on automata and YFilter, which is one of filtering techniques, is very popular. YFilter exploits commonality among path queries by sharing the common prefixes of the paths so that they are processed at most one and that is using the top-down approach. However, because partial matching path queries interrupt the common prefix sharing and don't calculate from root, throughput of YFilter decreases. So we use sharing of commonality among path queries with the common postfixes of the paths and use the bottom-up approach instead of the top-down approach. This filtering technique is called as PoSFilter. And we verify this technique through comparing with YFilter about throughput.

• The KIPS Transactions:PartD
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• v.8D no.4
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• pp.327-338
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• 2001

The view can provide the user an appropriate portion of the database through data integration and filtering. Views can be materialized for query performance improvement, and in that cse, their consistency needs to be maintained against the updates of the underlying data. They can be either recomputed or incrementally refreshed by reflecting the relevant updates. Since XML could represent the structural information of the documents, for the XML materialized views, new techniques that differ from the previous ones for incrementally refreshing the relational views are required. In this paper, we propose a framework of XML materialized view management where the XML view derived from the underlying XML documents are materialized and incrementally refreshed against the updates of the underlying documents.

• Journal of KIISE:Databases
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• v.30 no.3
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• pp.252-272
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• 2003

The view mechanism provides users with appropriate portions of database through data filtering and integration. In the Web era where information proliferates, the view concept is also useful for XML, a future standard for data exchange on the Web. This paper proposes a method of implementing XML views called XML view indexing, whereby XML view xv is represented as an XML view index(XVI) which is a structure containing the identifiers of xv's underlying XML elements as well as the information on xv. Since XVI for xv stores just the identifiers of the XML elements but not the elements themselves, when a user requests to retrieve xv, its XVI should be materialized against xv's underlying XML documents. Also an efficient algorithm to incrementally maintain consistency of XVI given a update of xv's underlying XML documents is required. This paper proposes and implements data structures and algorithms for XML view indexing. The performance experiments on XML view indexing reveal that it outperforms view recomputation for repeated accesses to the view, and requires as much as about 30 times less storage space compared to XML view materialization though the latter takes less time for repeated accesses to the view due to no need of materialization.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.3
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• pp.528-534
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• 2007

As XML is becoming a standard for representation and exchange of abundant information on the Web, solutions for a secure and selective dissemination of XML data, known as SDI, are strongly demanded. Such trends are more outstanding especially in distributed heterogeneous environment such as Peer-to-Peer. Although many approaches have been proposed to provide secure and efficient SDI mechanisms, almost previous approaches have focused only on filtering with user profile and they adopt center-oriented administration approaches. It is therefore difficult to adapt them directly to the distributed Peer-to-Peer environments characterized by dynamic participation. In this paper, we develop a novel dissemination method, which makesuse of authorization policy and secret sharing scheme. It provides more secure, scalable means for XML dissemination on Peer-to-Peer networks.

• The Journal of the Korea Contents Association
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• v.7 no.7
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• pp.31-38
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• 2007

We implement the RFID middleware system based on XML for large-scale data processing. The Implemented middleware system are consist of the reader interface for tag data collection, the event manager for a data filtering, and application interface for the RFID application. The implemented RFID middleware system is to support both a fixed type's reader and portable type's reader. we analyze the middleware function with four application accessing protocol, HTTP, XML, JMS, and SOAP, and demonstrate a filtering speed in terms of CPU utilization.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.50-58
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• 2007

We design a filtering management scheme with synchronization function under a realtime RFID middleware system for larger-scale data processing. The application interface(AI) is to support a various access protocol, HTTP, XML, JMS, and SOAP for the RFID applications. Generally, the synchronization problem is occurred in multiple accessing of clients for single filtering file. In this paper, we implement a filtering management scheme supporting the synchronization using the filter management process, and then demonstrate the RFID middleware filtering scheme.