• 한국경영정보학회:학술대회논문집
• /
• 한국경영정보학회 2008년도 춘계학술대회
• /
• pp.620-627
• /
• 2008

In this paper, recognizing the importance of the database query optimization design methods, we implemented mobile database with mobile program (J2ME) which is a useful database procedures. In doing so, we emphasize the logical query optimization which brings mobile database to performance improvement. The research implies that the suggested mobile program (J2ME) would contribute to the realization of the efficient mobile database as the related technology develops in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• 제16권12호
• /
• pp.8370-8377
• /
• 2015

In spatial data stream management systems, it is needed appropriate load shedding algorithm because real-time input spatial data streams could exceed the limitation of main memory. However previous researches, lack regard for input ratio and spatial utilization rates of spatial data streams, or the characteristics of data source which generates data streams with spatial information efficiently, can lead to decrease the performance and accuracy of spatial data stream query. Therefore, multi-level load shedding scheme for spatial data stream management systems is proposed to increase the spatial query performance and accuracy. This proposed scheme limits overloads in relation to the input rate and the characteristics of data source first, and then, if needed, query data representing low query participation probability based on spatial utilizations are dropped relatively. Our experiments show that the proposed method could decrease load shedding frequency for previous researches by more than 11% despite query results accuracy and query performance are superior at 0.04% and 3%.

• Journal of Korea Multimedia Society
• /
• 제14권2호
• /
• pp.269-281
• /
• 2011

For the MD-TIX(multidimensional type inheritance index) that supports query processing for the type inheritance concept in XML databases, this paper presents an index tuning algorithm that enhances the performance of the XML query processing according to the query pattern. The MD-TIX uses a multidimensional index structure to support complex XML queries involving both nested elements and type inheritance hierarchies. In this index tuning algorithm, we first determine a shape of index page regions by using the query information about the user's query pattern, and then construct an optimal MD-TIX by applying a region splitting strategy that makes the shape of the page regions into the predetermined one. The performance evaluation results indicate that the proposed tuning algorithm builds an optimal MD-TIX by a given query pattern, and in the case of the three-dimensional query regions for the nested predicates of path length 2, the performance is much enhanced according to the skewed degree of the query region's shape.

• Journal of the Korean Society for information Management
• /
• 제23권2호
• /
• pp.229-243
• /
• 2006

This study aims to suggest an effective way to enhance question-answer(QA) document retrieval performance by reconstructing queries based on the structural features in the QA documents. QA documents are a structured document which consists of three components : question from a questioner, short description on the question, answers chosen by the questioner. The study proposes the methods to reconstruct a new query using by two major structural parts, question and answer, and examines which component of a QA document could contribute to improve query performance. The major finding in this study is that to use answer document set is the most effective for reconstructing a new query. That is, queries reconstructed based on terms appeared on the answer document set provide the most relevant search results with reducing redundancy of retrieved documents.

• Journal of KIISE:Databases
• /
• 제32권2호
• /
• pp.177-192
• /
• 2005

In this paper, we introduce a structural redundancy method. It reduces the query processing cost incurred when reconfiguring an XML document from divided XML data in shredding XML documents into relations. The fundamental idea is that query performance can be enhanced by analyzing query patterns and replicating data essential for the query performance. For the practical and effective structural redundancy, we analyzed three types of ID, VALUE, and SUBTREE replication. In addition, if given XML data and queries are very large and complex, it can be very difficult to search optimal redundancy set. Therefore, a heuristic search method is introduced in this paper. Finally, XML query processing cost arising by employing the structural redundancy, and the efficiency of proposed search method arc analyzed experimentally It is manifest that XML read query is performed more quick]y but XML update query is performed more slowly due to the additional update consistency cost for replicas. However, experimental results showed that in-place ID replication is useful even in having excessive update cost. It was also observed that multiple-place SUBTREE replication can enhance read query performance remarkably if only update cost is not excessive.

• Asia pacific journal of information systems
• /
• 제9권2호
• /
• pp.1-17
• /
• 1999

A feedback echo is a structured restatement of the user's query and informs the user what the system intends to do for the query. This provides backtracking of the user's query so that the user knows how the system has interpreted the query. This study scrutinizes whether the feedback echo, as currently available in the INTELLECT commercial system, can improve the performance of a casual user using a restricted natural language database interface. This study concludes that the particular type of feedback echo available in this commercial system was not effective in terms of overall performance for casual users. It is worth mentioning, however, that the feedback echo was effective for the specific type of error: using wrong conditions for data retrieval.

• Journal of information and communication convergence engineering
• /
• 제11권3호
• /
• pp.173-178
• /
• 2013

To discover objects of interest in unstructured peer-to-peer networks, the peers rely on flooding query messages which create incredible network traffic. This article evaluates the performance of an unstructured Gnutella-like protocol over mobile ad-hoc networks and proposes modifications to improve its performance. This paper offers an enhanced mechanism for an unstructured Gnutella-like network with improved peer features to better meet the mobility requirement of ad-hoc networks. The proposed system introduces a novel caching optimization technique and enhanced ultrapeer selection scheme to make communication more efficient between peers and ultrapeers. The paper also describes an enhanced query mechanism for efficient searching by applying multiple walker random walks with a jump and replication technique. According to the simulation results, the proposed system yields better performance than Gnutella, XL-Gnutella, and random walk in terms of the query success rate, query response time, network load, and overhead.

• The Journal of the Korea Contents Association
• /
• 제8권1호
• /
• pp.290-299
• /
• 2008

We propose the query optimization technique using query classification in hybrid spatial DBMS. In our approach, user queries should to be classified into three types: memory query, disk query, and hybrid query. Specialty, In the hybrid query processing, the query predicate is divided by comparison between materialized view creating conditions and user query conditions. Then, the deductions of the classified queries' cost formula are used for the query optimization. The optimization is mainly done by the selection algorithm of the smallest cost data access path. Our approach improves the performance of hybrid spatial DBMS than traditional disk-based DBMS by $20%{\sim}50%$.

• Journal of KIISE:Databases
• /
• 제30권4호
• /
• pp.408-419
• /
• 2003

Data warehouses are usually dedicated to the processing of quires issued by decision support system(DSS). The response time of DSS queries is typically several orders of magnitude higher than the one of OLTP queries. Since DSS queries are often submitted interactively, techniques for reducing their response time are important. The caching of query results is one such technique particularly well suited to the DSS environment. In this paper, we present a cache manager for such an environment. Specifically, we define a canonical form of query. The cache manager looks up a query based on the exact query match or using a suggested query split process if the query is found is non-canonical form or in canonical form, respectively. It dynamically maintains the cache content by employing a profit function which reflects in an integrated manner the query execution cost, the size of query result, the reference rate, the maintenance cost of each result due to updates of their base tables, and the frequency of such updates. We performed the experimental evaluation and it positively shows the performance benefit of our cache manager.

• Journal of Information Processing Systems
• /
• 제5권1호
• /
• pp.11-18
• /
• 2009

As well as providing various APIs for the development of inference engines and storage models, Jena is widely used in the development of systems or tools related with Web ontology management. However, Jena still has several problems with regard to the development of real applications, one of the most important being that its query processing performance is unacceptable. This paper proposes a storage model to improve the query processing performance of the original Jena storage. The proposed storage model semantically classifies OWL elements, and stores an ontology in separately classified tables according to the classification. In particular, the hierarchical knowledge is managed, which can make the processing performance of inferable queries enhanced and stores information. It enhances the query processing performance by using hierarchical knowledge. For this paper an experimental evaluation was conducted, the results of which showed that the proposed storage model provides a improved performance compared with Jena.