• Journal of the Korean Operations Research and Management Science Society
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• v.20 no.2
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• pp.139-158
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• 1995

A temporal database systems provides timing information and maintains history of data compared to the conventional database system. In this paper, we present a temporal relational database which use an interval-stamping method for instant-based events and for interval-based states. A set of temporal algebraic operators are developed on an instance of time and interval of time so that we can manipulate events and states at a same time. The set of operation is the basis for creating a relational algebra that is closed for temporal relations. And temporal SQL is also suggested as a temporal query relational language for our algebraic operations on temporal relations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.631-634
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• 2014

When to build a Web and Cloud Computing environment, it is essential to used a database system. Database systems includes commercial programs, such as Oracle and MS-SQL, but also similar to the performance of commercial applications, there are many free programs. In particular, PostgreSQL, MySQL, MariaDB are no costs, but the source is open to the public can be applied to a variety of environments. This paper presents an open source relational database management system, the trends are examined.

• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.221-232
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• 2003

This paper addresses the query processing component of a wrapper system for a relational database model based on the XML view in integrating databases. The schema of a relational database is represented as XML Schema that is proposed by W3C. Users submit a query using the XML query language XQuery over the XML Schema. The wrapper system to be developed supports an user-defined XML view. XQuery is also used as the view definition language. In this environment, this paper suggests a new XML query processing model. We propose the composition algorithm of an XML view with an user query, the translation algorithm of XQuery into SQL, and the XML template construction algorithm for generating XML documents.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.6
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• pp.743-748
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• 2003

In this research, we propose a mechanism to develop an inference engine and expert systems based on relational database (RDB) and SQL (structured query language). Generally, former researchers had tried to develop an expert systems based on text-oriented knowledge base and backward/forward (chaining) inference engine. In these researches, however, the speed of inference was remained as a tackling point in the development of agile expert systems. Especially, the forward inference needs more times than backward inference. In addition, the size of knowledge base, complicate knowledge expression method, expansibility of knowledge base, and hierarchies among rules are the critical limitations to develop an expert system. To overcome the limitations in speed of inference and expansibility of knowledge base, we proposed a relational database-oriented knowledge base and forward inference engine. Therefore, our proposed mechanism could manipulate the huge size of knowledge base efficiently. and inference with the large scaled knowledge base in a short time. To this purpose, we designed and developed an SQL-based forward inference engine using relational database. In the implementation process, we also developed a prototype expert system and presented a real-world validation data set collected from medical diagnosis field.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.223-225
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• 2013

For a long time, Relational Databases have been widely used in many enterprises. Even though the Relational Databases have merits such as excellent power of data preservation, concurrency controlling as a standard model in databases, there are a demerit in the inconsistency of objects and relations. Against this backdrop, NoSQL is being magnified as a new solution for Big Data since it can be operated without any schema. In this paper, we research on not only merits and demerits of Relational Databases but also the comparison between application databases and integrated databases. And then, we define NoSQL for Big Data and check its characteristics.

• Journal of Information Processing Systems
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• v.10 no.3
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• pp.355-364
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• 2014

Internet accessibility has been growing due to the diffusion of smartphones in today's society. Therefore, people can generate data anywhere and are confronted with the challenge that they should process a large amount of data. Since the appearance of relational database management system (RDBMS), most of the recent information systems are built by utilizing it. RDBMS uses foreign-keys to avoid data duplication. The transactions in the database use attributes, such as atomicity, consistency, isolation, durability (ACID), which ensures that data integrity and processing results are stably managed. The characteristic of RDBMS is that there is high data reliability. However, this results in performance degradation. Meanwhile, from among these information systems, some systems only require high-performance rather than high reliability. In this case, if we only consider performance, the use of NoSQL provides many advantages. It is possible to reduce the maintenance cost of the information system that continues to increase in the use of open source software based NoSQL. And has a huge advantage that is easy to use NoSQL. Therefore, in this study, we prove that the leverage of NoSQL will ensure high performance than RDBMS by applying NoSQL to database systems that implement RDBMS.

• Journal of the Korea Society of Computer and Information
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• v.23 no.3
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• pp.49-54
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• 2018

A data warehouse is a system that collectively manages and integrates data of a company. And provides the basis for decision making for management strategy. Nowadays, analysis data volumes are reaching critical size challenging traditional data ware housing approaches. Current implemented solutions are mainly based on relational database that are no longer adapted to these data volume. NoSQL solutions allow us to consider new approaches for data warehousing, especially from the multidimensional data management point of view. In this paper, we extend the data warehouse design methodology based on relational database using star schema, and have developed a consistent design methodology from information requirement analysis to data warehouse construction for large scale data warehouse construction based on MongoDB, one of NoSQL.

• Journal of the Korea Society of Computer and Information
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• v.23 no.3
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• pp.41-48
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• 2018

The recent sudden increase of big data has characteristics such as continuous generation of data, large amount, and unstructured format. The existing relational database technologies are inadequate to handle such big data due to the limited processing speed and the significant storage expansion cost. Current implemented solutions are mainly based on relational database that are no longer adapted to these data volume. NoSQL solutions allow us to consider new approaches for data warehousing, especially from the multidimensional data management point of view. In this paper, we develop and propose the integrated design methodology based on MongoDB for big data applications. The proposed methodology is more scalable than the existing methodology, so it is easy to handle big data.

• The KIPS Transactions:PartD
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• v.9D no.5
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• pp.789-800
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• 2002

XML is a standard format of web data and is currently used as a prevailing language for exchanging data. Most of the commercial data are stored in a relational database. It is quite important to convert these conventionally stored data into those for exchange and use them in data exchange, or to get the query results effectively by utilizing XQL on XML data which are store in a relational database. Thus, it is absolutely required to have a proper query processing mechanism for XML data and to maintain many XML data properly. Up to now, many cases of researches on the storage and retrieval of XML data have been carried out and under study. But, effective retrieval and storage system for path queries like XQL has yet to be contrived. Thus, in this paper, a schema to store XML data is designed, in which DFS-Numbegering method is used to store data effectively. And an effective path query processing method is also designed and implemented, in which a traditional relational database engine is used. That is, XQL is converted into SQL with a XQL processor if a user makes query XQL in a system. A database system executes SQL, and a XML generator uses a generated record and makes a XML document.