• Asia pacific journal of information systems
• /
• 제8권1호
• /
• pp.43-64
• /
• 1998

Cooperative query answering is a research effort to develop a fault-tolerant and intelligent database system using the semantic knowledge base constructed from the underlying database. Such knowledge base has two aspects of usage. One is supporting the cooperative query answering process for providing both an exact answer and neighborhood information relevant to a query. The other is supporting ongoing maintenance of the knowledge base for accommodating the changes in the knowledge content and database usage purpose. Existing studies have mostly focused on the cooperative query answering process but paid little attention to the dynamic knowledge base maintenance. This paper proposes a multi-level knowledge representation framework called Knowledge Abstraction Hierarchy(KAH) that can not only support cooperative query answering but also permit dynamic knowledge maintenance, On the basis of the KAH, a knowledge abstraction database is constructed on the relational data model and accommodates diverse knowledge maintenance needs and flexibly facilitates cooperative query answering. In terms of the knowledge maintenance, database operations are discussed for the cases where either the internal contents for a given KAH change or the structures of the KAH itself change. In terms of cooperative query answering, four types of vague queries are discussed, including approximate selection, approximate join, conceptual selection, and conceptual join. A prototype system has been implemented at KAIST and is being tested with a personnel database system to demonstrate the usefulness and practicality of the knowledge abstraction database in ordinary database application systems.

• 반도체디스플레이기술학회지
• /
• 제22권2호
• /
• pp.45-49
• /
• 2023

When blockchain technology, which shows various applicability, is utilized as a component of a database system, the characteristics of open verification and integrity/transparency of blockchain technology can bring new functionalities or enhanced results to the existing database system. However, when applying this blockchain technology to a database system, the cost versus expected effect in various performance perspectives must be evaluated. These costs include execution time and required storage space, and the performance of the converged system may vary in analysis method depending on the configuration method of the characteristics of the blockchain. This paper aims to propose an analysis model for the entire architecture by considering aspects that are not considered in the performance analysis models of database systems and the unique characteristics of blockchains. In doing so, we are trying to build a theoretical framework as an important conceptual technique that should be considered in the evaluation process of the performance results that can be obtained through the utilization of blockchain components in database systems. What we hope is that this work is expected to provide a useful foundation for researchers interested in the convergence of database systems and blockchain technology in order to construct a system with new future functionalities.

• 한국통신학회논문지
• /
• 제22권9호
• /
• pp.1867-1879
• /
• 1997

DREAM-S는 ATM 네트워크용 교환 시스템에서 응용 프로그램들의 교환기 운용 데이터에 대한 실시간 처리 요구를 지원하기 위한 분산 주기억장치 상주 데이터베이스 시스템(Main Memory Database Systems)이다. DREAM-S는 클라이언트-서버 구조를 가지면서 서버 프로세서에만 디스크가 연결되어 있으며, 대량의 데이터로부터 원하는 데이터를 신속히 검색하기 위하여 T- Tree 색인 구조를 제공한다. 본 논문에서논 DREAM-S에서 T- Tree 색인 구조에 대한 회복 기법를 제안한다. 주기억장치 상주 데이터베이스는 디스크 상주 데이터베이스 보다 뛰어난 성능을 제공하지만 시스템 고장 시(정전 등과 같은 오류) 주기억장치에 저장된 모든 데이터(릴레이션과 색인 구조)가 파손될 수 있다. 따라서 고장 후 파손된 주기억장치 데이터베이스를 신속히 정상 데이터베이스 상태로 회복하는 회복 기법이 필수적이다. 제안된 회복 기법에서는 T-Tree 색인 구조를 각 프로세서의 주기억장치에만 유지하도록 함으로서 ATM 교환기 시스템의 성능에서 병복 현상을 일으킬 수 있는 서버 프로세서의 디스크 출입 오버헤드를 줄인다. 또한, 시스템 고장 후 서버와 모든 클라이언트 시스템들이 병렬 처리 방식으로 각자의 T- Tree(들)를 회복하도룩 함으로서 클라이언트 개수가 많은 경우에도 신속한 회복이 가능하도록 하였다.

• 정보보호학회논문지
• /
• 제17권1호
• /
• pp.109-113
• /
• 2007

실생활에서 네트워크가 차지하는 비중이 점점 커지면서 데이터가 집약되어있는 데이터베이스 보안의 중요성도 점점 증가하고 있다. 현재 데이터베이스 보안은 크게 사용자 접근제어 방식과 데이터의 암호화 저장방식으로 구분된다. 그러나 데이터베이스 보안시스템에 대한 범용의 보호프로파일이 아직 존재하지 않기 때문에 정확한 평가가 어렵다. 이에 본 논문은 사용자 접근제어 형 데이터베이스 보안시스템의 보안기능요구사항을 개발한다. 본 논문은 접근제어 형 데이터베이스 보안시스템이 갖춰야 할 기본적인 필수기능을 제안한다. 이는 데이터베이스 보안시스템 평가 시 참고자료로 충분히 활용될 수 있을 것이다.

• 한국정보처리학회논문지
• /
• 제4권1호
• /
• pp.29-53
• /
• 1997

기존의 교환기 시스템은 주로 화일 시스템이나 관계형 데이터베이스를 이용하여 교환기 운용에 관련된 데이타를 관리해 오고 있다. 하지만, 통신망이 급속히 발전하 면서 교환기에 다양한 기능이 요구됨에 따라 관계형 데이타베이스 시스템으로는 효과 적인 데이타 관리가 어렵게 되었다. 본 연구는 교환기 시스템을 위한 관계형 데이타 베이스 시스템인 DREAM을 확장하여, 보다 강력한 데이타 모델링 기능을 지원하여 객 체지향 인터페이스를 제공하는 방안을 제시한다. 아울러, 제시하는 기법을 DREAM 시 스템 상에 적용하는 과정을 예시한다.

• 지능정보연구
• /
• 제9권2호
• /
• pp.19-38
• /
• 2003

In this research, we propose the mechanism to develop self-evolving expert systems (SEES) based on data mining (DM), fuzzy neural networks (FNN), and relational database (RDB)-driven forward/backward inference engine. Most researchers had tried to develop a text-oriented knowledge base (KB) and inference engine (IE). However, this approach had some limitations such as 1) automatic rule extraction, 2) manipulation of ambiguousness in knowledge, 3) expandability of knowledge base, and 4) speed of inference. To overcome these limitations, knowledge engineers had tried to develop an automatic knowledge extraction mechanism. As a result, the adaptability of the expert systems was improved. Nonetheless, they didn't suggest a hybrid and generalized solution to develop self-evolving expert systems. To this purpose, we propose an automatic knowledge acquisition and composite inference mechanism based on DM, FNN, and RDB-driven inference engine. Our proposed mechanism has five advantages. First, it can extract and reduce the specific domain knowledge from incomplete database by using data mining technology. Second, our proposed mechanism can manipulate the ambiguousness in knowledge by using fuzzy membership functions. Third, it can construct the relational knowledge base and expand the knowledge base unlimitedly with RDBMS (relational database management systems) module. Fourth, our proposed hybrid data mining mechanism can reflect both association rule-based logical inference and complicate fuzzy relationships. Fifth, RDB-driven forward and backward inference time is shorter than the traditional text-oriented inference time.

• Journal of Information Processing Systems
• /
• 제10권3호
• /
• pp.355-364
• /
• 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.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
• /
• pp.1079-1084
• /
• 2002

Systems engineering technology development program for Korea next-generation high-speed railway(KNHR) system in progress is a national large-scale system development program that is not only a large-size and complex but also multi-disciplinary in nature. Using the RDD-IOO, a systems engineering tool, the KNHR program can establish requirements traceability and development process management in the course of development. This paper presents the results from a computer-aided systems engineering application to KNHR system technology development project over the three years of activities. The traceability among the system design database in the vertical direction of SE process, as the results of the first year and the second year research was accomplished. The database in both the requirement management domain and the project management domain was developed and set up the traceability between them in the horizontal direction of the SE process in the V model as the results of the third year research. Therefore, KNHR design database was built to support the life-cycle management of the system as well as to reuse the knowledge in future programs. In the following development phase, this database will be utilized to accomplish the test and integration activities providing a baseline database. The outcome of the study contributes to the establishment of the model-based systems engineering approach as a best practice in the accumulation and advancement of systems engineering technology for railway system development.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
• /
• pp.292-295
• /
• 2003

In this paper, we propose an approach which contains with constructing a bibliography information database, extracting the fields of research, and researching trend of them, using data mining. To apply our approach to IEICE Technical Report (nonlinear problem society), the database was constructed based on its report, keywords were analyzed using the frequency analysis and the association analysis, and we discussed about the result. We could extract some field of research from the result.

• 한국정보시스템학회지:정보시스템연구
• /
• 제4권
• /
• pp.85-104
• /
• 1995

In a loosely-coupled distributed database server system, a server failure and/or a communication failure can be masked by a resiliency mechanism. Recognizing that a distributed transaction executes at several servers during its lifetime, we propose a resiliency mechanism which allows continuous transaction processing in distributed database server systems in the presence of a server failure. The resiliency mechanism for transaction processing is achieved by keeping redundant information using a primary/backup approach. The purpose of this paper is to analyze the performance improvement opportunities with the resiliency mechanism and to present the design of the proposed system.