• The Journal of Information Technology and Database
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• v.7 no.2
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• pp.1-15
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• 2000

The World-Wide-Web have many advantages as a front-end of database systems. Hence in Internet applications, such as E-Commerce systems, the requirements for Web-based database applications have been increasing. In this work we propose a framework for java-based Web database applications-JaWAF(Java-based Web Application Framework). JaWAF has the 3-tier architecture of Client/Server, and consists of database gateway, application server, and communication and message component. When this framework is applied to the database applications developments, it can provide advantages, such as ease understanding and fast implementations of the Web applications. Thus we can build 3-tier Web-based database application systems with high scalability and distributed processing capability. Database gateway in JaWAF works as a daemon process that connects to the database systems and waits for requests from clients, and supports state-oriented service between clients and database servers. Hence the performance of Web applications could be increasing.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1996.10a
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• pp.223-226
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• 1996

One of the consideration issue in implementation and maintanence of CIM(Computer Integrated Manufacturing) database is exchange and sharing of information between heterogeneous databases. For efficient operating of SIM systems, it must be able to organize and to manage the information. In this paper, we propose method that can make enhance the efficiency of CIM database, classfying the data in database using self organize neural network to each database systems, and computing between classfied heterogeneous database using extended operator that is defined.

• Journal of the Semiconductor & Display Technology
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• v.3 no.4
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• pp.13-17
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• 2004

As the usage of wireless LAN becomes common in working environment, the number of database systems that support both wired and wireless users increases rapidly. The characteristics of wireless LAN that its speed is slow relatively comparing to wired network and the users in its environment connects to different communication points as they moves creates another challenge to be resolved in database systems. In the environment of hybrid communication systems, wired and wireless for voluminous data amount and a number of users, the two layer architecture of the conventional client-server database systems has limitation in the system performance. This is due to that server is the only point of data service in client-server database systems. In this paper, we discuss a new extended database system architecture that data services are distributed among servers and clients based on user database access patterns in order to improve system performance. We analyze the expected system performance by using simulation technique and prove the practical utilization of the system by demonstrating experimental results.

• Journal of Industrial Technology
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• v.15
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• pp.51-62
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• 1995

Databases can crash due to various failures in computer systems. Recovery is a mechanism for restoring consistent data from damages caused by the by the failures and is an essential feature in database systems. This paper surveys recovery techniques for memory resident database systems. We first describe the basic architecture for memory resident database systems, and point out the main factors affecting their performance enhancement. Next, we explain the write-ahead logging(WAL), a recovery technique widely-used in most disk resident database systems, for easy understanding of basic recovery mechanisms. And then, we discuss some new concepts employed in memory resident database systems recovery. Finally, we present a representative memory resident database recovery technique, which is based on a special purpose hardware called HALO, as a case study.

• Journal of Information Processing Systems
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• v.11 no.3
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• pp.389-405
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• 2015

Most traditional database systems exploit a record-oriented model where the attributes of a record are placed contiguously in a hard disk to achieve high performance writes. However, for read-mostly data warehouse systems, the column-oriented database has become a proper model because of its superior read performance. Today, flash memory is largely recognized as the preferred storage media for high-speed database systems. In this paper, we introduce a column-oriented database model based on flash memory and then propose a new column-aware flash indexing scheme for the high-speed column-oriented data warehouse systems. Our index management scheme, which uses an enhanced $B^+$-Tree, achieves superior search performance by indexing an embedded segment and packing an unused space in internal and leaf nodes. Based on the performance results of two test databases, we concluded that the column-aware flash index management outperforms the traditional scheme in the respect of the mixed operation throughput and its response time.

• 한국디지털정책학회:학술대회논문집
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• 2003.12a
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• pp.263-273
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• 2003

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.

• The Transactions of the Korea Information Processing Society
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• v.7 no.7
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• pp.1997-2007
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• 2000

This paper presents a new benchmark for object-relational database systems, which are regarded as the next-generation database system. This benchmark has been developed to evaluate system performance peculiar to object-relational database systems. The design philosophy, test databases, an test queries of the benchmark are presented. This benchmark features scaleability, use of a synthesized database only, and a query-oriented evaluation. We have implemented his benchmark with two commerical object-relational database systems and the experimental results are also reported.

• The Journal of Information Systems
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• v.6 no.2
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• pp.147-163
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• 1997

The usages of the relational database systems have been increased nowadays. However there is a constraint that the standard query language for a database system requests users to know the exact condition for a query. In this paper a FSQL(Fuzzy SQL) systems is proposed and implemented for the imprecise queries which do not include the exact condition. Moreover this system can supply the obvious results for the queries effectively. We define a simple fuzzy query language and use a method using the metadatabase to implement the FSQL system. This FSQL system can be combined with a relational database system without any painful effort.

• Journal of Intelligence and Information Systems
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• v.5 no.1
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• pp.13-34
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• 1999

Building a knowledge base effectively has been an important research area in the expert systems field. A variety of approaches have been studied including rules, semantic networks, and frames to represent the knowledge base for expert systems. As the size and complexity of the knowledge base get larger and more complicated, the integration of knowledge based with database technology cecomes more important to process the large amount of data. However, relational database management systems show many limitations in handing the complicated human knowledge due to its simple two dimensional table structure. In this paper, we propose Object-Oriented Knowledge Store (OOKS), a knowledge base model on the basis of a frame sturcture using an object-oriented database. In the proposed model, managing rules for inferencing and facts about objects in one uniform structure, knowledge and data can be tightly coupled and the performance of reasoning can be improved. For building a knowledge base, a knowledge script file representing rules and facts is used and the script file is transferred into a frame structure in database systems. Specifically, designing a frame structure in the database model as it is, it can facilitate management and utilization of knowledge in expert systems. To test the appropriateness of the proposed knowledge base model, a prototype system has been developed using a commercial ODBMS called ObjectStore and C++ programming language.

• The KIPS Transactions:PartD
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• v.9D no.2
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• pp.227-234
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• 2002

When processing a query in a conventional database systems, a set of facts or tuples are usually returned as an answer. This also applies to object -oriented database where a set of objects is returned. Deductive database systems, however, provide the opportunity to obtain the answer of a query as a set of formulas, thereby reduce the costs to process the query, and represent its "intensional answers" in a more compact way independently of the database state. In this paper, by introducing rules info the object-oriented database systems and integrating the intensional query processing of deductive database systems into talc object-oriented database systems, we make it possible not only to answer incomplete queries which are not able to be answered in conventional object-oriented database systems, but also to express the answer-set abstractly as the names of classes, which provides us better understanding of the answer.