• The Transactions of the Korea Information Processing Society
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• v.7 no.6
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• pp.1746-1752
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• 2000

In this paper, a cache mechanism is proposed to improve the speed of query processing in distributed director database systems. To decrease search time of requested objects and query processing time. query requests and results about objects in a remote site are stored in the cache of a local site. Cache system architecture is designed according to the classified information. Cache schema are designed for each cache information. Operational algorithms are developed for meta data cache which has meta data tree. This tree improves the speed of query processing by reducing the scope of search space. Finally, performance evaluation is performed by comparing the proposed cache mechanism with X500.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2297-2311
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• 1994

This paper presents the study on the development of a DNC, system IPIS(Interactive Plant Information System)/DNC, which can manage NC machines and robots as a distributed control method in the machine. processing factory. The IPIS/DNC system is composed of a host computer, satellites and NC machines. A set of software modules are developed on the host computer and the satellites separately. By modularizing each functions of the IPIS/DNC system and using multi-taking method, the functions such as NC program management, NC program distribution, and shop monitoring can be performed on the host computer, and the functions such as NC program transfer to the NC machines, and NC program editing can be performed on the satellites. A Relational database which is linked with job scheduling system is used for IPIS/DNC system.

• Asia pacific journal of information systems
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• v.1 no.1
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• pp.49-62
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• 1991

This paper examines the problems of database partitioning and file allocation in a fixed topology distributed computer network. The design objective is to make files as collections of attributes and to allocate these files to network nodes so that a minimum total transmission cost is achieved subject to storage capacity constraints. A mathematical model for solving the problem is formulated and, the resulting optimization problem is shown to fall in a class of NP-complete problems. A new heuristic algorithm is developed which uses the idea of allocating attributes according to the transaction requirements at each computer node and then making files using the allocated attributes. Numerical results indicate that the heuristic algorithm yields practicable low cost solutions in comparison with the existing methods which deal with the file allocation problems and database partitioning problems independently.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.2875-2888
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• 1999

In this paper we present compiler-based active rule system to efficiently maintain spatial integrity constraints in a heterogeneous, distributed environment. Specially, the prototype active rule system presented has been developed as a component of a whole middleware system called SDBC(Spatile DataBase Connectivity). Due to this reason, our active rule system is provided for heterogeneous ODBMSs in a distributed environment and used to define spatial integrity constraints using the active rules in E-C-A(Event-Condition-Action) type. Using this active rule system, an application programmer can free himself from a heavier burden on the integrity maintenance of application objects. In the compiler-based approach, active rules applicable to events raised by a database program are directly inserted into the program in a function type by the preprocessor, and then they are compiled with the application program source codes. One advantage of this approach is that there is no run-time overhead accompanied by monitoring all the database transitions when preprocessed program is executed. This active rule system also provides facilities to manage changed rules and dynamically interpret those rules at run-tuime.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10c
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• pp.77-82
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• 2006

최근 컴퓨팅 환경은 클라이언트-서버(client-server) 환경에서 웹(World Wide Web)을 기반으로 한 분산 컴퓨팅(distributed computint) 환경으로 변화하고 있다. 그에 따라 XML 문서의 사용과 XML 문서의 양이 급속하게 증가하였다. 언제 어디서나 쉽게 필요한 XML 문서에 접근해야하며, 이러한 응용을 위해 짧은 시간 내에 그 정보를 전달할 수 있어야 한다. 이에 따라 분산 환경에서의 XML 문서의 처리가 요구된다. XML 데이터를 분산 데이터베이스의 특성을 이용하여 저장, 관리, 질의하는 분산 XML 데이터베이스 시스템(Distributed XML Database System)의 사용의 필요성이 증가하고 있다. 이에 따라, 사이트의 자치성, 질의 최적화, 데이터의 투명성 등에 큰 영향을 미치는 분산 XML 데이터베이스 시스템에서의 카탈로그 관리 기법의 연구의 필요성이 증가하게 된다. 본 논문에서는 중앙 집중식 카탈로그와 완전 중복식 카탈로그, 분할식 카탈로그를 분산 XML 데이터베이스 시스템에서 CPU 비용, I/O 비용, 동시성 제어, 이단계 완료 프로토콜, 큐잉 지연 등을 모두 고려한 모델을 설계하였고, 이를 시뮬레이터로 구현하여 각 카탈로그 관리 기법들의 성능을 합리적인 환경 설정을 통해 시뮬레이션함으로써 카탈로그 관리 기법들의 성능을 평가하였다.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.81-87
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• 2010

This paper proposes a G-BLAST(BLAST using Grid Computing) system, an integrated software package for BLAST searches operated in heterogeneous distributed environment. G-BLAST employed 'database splicing' method to improve the performance of BLAST searches using exists computing resources. G-BLAST is a basic local alignment search tool of DNA Sequence using grid computing in heterogeneous distributed environment. The G-BLAST improved the existing BLAST search performance in gene sequence analysis. Also G-BLAST implemented the pipeline and data management method for users to easily manage and analyze the BLAST search results. The proposed G-BLAST system has been confirmed the speed and efficiency of BLAST search performance in heterogeneous distributed computing.

• The Transactions of the Korea Information Processing Society
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• v.7 no.1
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• pp.20-28
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• 2000

In distributed data processing environments, heterogeneous data sources should corporate each other. The CORBA standards proposed by OMG solve this problem by the integration of platform independent applications. In this paper, we design and implement a CASE tool that help linking CORBA applications to relational databases by interface method. This CASE tool manipulates the database schema and generates IDL and $C^{++}$ stubs corresponding to the schema. We explain the code generation process and evaluate the data access performance of the interface method compared to adapter method and various implementation languages. The implemented tool can be used for developing applications that need relational database corporation environments such as distributed information systems or data warehousing. etc.

• The KIPS Transactions:PartD
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• v.16D no.3
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• pp.295-306
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• 2009

Query execution time minimization is an important objective in distributed database design. While total time minimization is an objective for On Line Transaction Processing (OLTP), response time minimization is for Decision Support queries. We formulate the sub-query allocation problem using analytical models and solve with genetic algorithm (GA). We show that query execution plans with total time minimization objective are inefficient from response time perspective and vice versa. The procedure is tested with simulation experiments for queries of up to 20 joins. Comparison with exhaustive enumeration indicates that GA produced optimal solutions in all cases in much less time.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.175-181
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• 2006

AMobile-supported spatial database systems have been introduced with development of mobile computing technology, they offer an advantage that we can access the data wherever we are. However, the studies on database system in traditional distributed environments must be reconsidered again, because of characteristics of mobile database system such as mobility and instability of wireless network. A new transaction model should be required for considering the characteristics, since especially a mobile computing environment is location-dependent, compared with the location transparency in a distributed computing environment. In other aspect, normally mobile host may be moving not in all space, but in some limited path. That is, a host is moving along the roads or the geographical features adjacent to the roads. The transaction processing should be considered not on the spatial coordinate but on the geographical features. In this paper, the feature based transaction processing model is proposed to process location-dependent transaction efficiently.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1997.10a
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• pp.25-25
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• 1997