• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2003.06a
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• pp.73-74
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• 2003

• Journal of Korea Spatial Information System Society
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• v.8 no.3
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• pp.1-14
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• 2006

Recently, to efficiently support the real-time requirements of LBS and Telematics services, interest in the spatial main memory DBMS is rising. In the spatial main memory DBMS, because all spatial data can be lost when the system failure happens, the recovery system is very important for the stability of the database. Especially, disk I/O in executing the log and the checkpoint becomes the bottleneck of letting down the total system performance. Therefore, it is urgently necessary to research about the recovery system to reduce disk I/O in the spatial main memory DBMS. In this paper, we study an efficient recovery system for the spatial main memory DBMS. First, the pre-commit log method is used for the decrement of disk I/O and the improvement of transaction concurrency. In addition, we propose the fuzzy-shadow checkpoint method for the recovery system of the spatial main memory DBMS. This method can solve the problem of duplicated disk I/O on the same page of the existing fuzzy-pingpong checkpoint method for the improvement of the whole system performance. Finally, we also report the experimental results confirming the benefit of the proposed recovery system.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1724-1737
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• 1999

Multimedia data service applications have to store and manipulate LOBs(unstructured large objects) composing multimedia data. As such, the tertiary storage devices such as an optical disk jukebox and a tape library that consist of a number of platters (the disks in case of an optical disk jukebox and the cartridge tapes in case of a tape library) have been considered essential for the storage system of a DBMS in order to efficiently support storage and management of vary large volume of data. Since the latency with tertiary storage is too long, the schemes for efficient retrieval of LOBs out of tertiary storage need to be investigated. In this paper, we investigated the tertiary I/O Considering the performance characteristics of the LOBs, we proposed various I/O scheduling heuristic algorithms that reduce latency in query processing with LOB retrieval from tertiary storage, and evaluated their performance through a detailed simulation.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.8
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• pp.287-296
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• 2018

In the recent commercial DBMS market, as the users' burden and complaint which are related to high price licensing policy and late technical support service are increasingly rising, the concern for use of open source DBMS which has no problem with compatibility or stability is escalating. Due to the fact, the cases saving the cost are growing by converting Oracle Corporation's applications, which has about 60% share in the DBMS market, to an open source DBMS. However, in converting non-interchange sentences to an ANSI standard-based open source DBMS because of the use of PL/SQL in Oracle Corporation provides, a lot of manual work accompanies, so there is a lot of loss of time and money. Therefore, a tool that automatically converts PL/SQL to standard SQL is required. The proposed automation tool for the conversion of applications converts PL/SQL to Java Stored Procedure, an open source DBMS-based ANSI standard programming language. Through carrying out a test on the automation tool, it is proved that the tool will contribute to shortening time and saving cost by verifying the identity of input-output data and its reliability after correcting errors in converting to Java Stored Procedure.

• The KIPS Transactions:PartD
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• v.15D no.5
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• pp.589-598
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• 2008

Recently, Mobile Computing Devices are used generally. And Information which is processed by Mobile computing devices is increasing. Because information is digitalizing. So Mobile computing Devices demand an Embedded DBMS for efficient management of information. Moreover Mobile computing Devices demand an efficient storage management in NAND-type flash memory because the NAND-type flash memory is using generally in Mobile computing devices and the NAND-type flash memory is more expensive than the magnetic disks. So that in this paper, we present an efficient Compressed Data Management System for the embedded DBMS that is used in flash memory. This proposed system improve the space utilization and extend a lifetime of a flash memory because it decreases the size of data.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.763-766
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• 2014

플래시 메모리는 입출력 속도가 빠르고 에너지 효율성이 좋지만, out-place update만 가능하며 쓰기 연산을 위한 IO의 지연시간이 읽기 연산보다 현저히 길다는 단점을 가진다. 이를 보완하기 위해 고안된 FlashSSD(Solid State Drive)는 최근 하드 디스크를 대체하는 저장장치로 주목받고 있다. DBMS(Database Management System)의 성능 개선을 위하여 FlashSSD를 활용한 다양한 연구가 진행되었다. 그중 FD-tree를 사용한 인덱스는 좋은 갱신 성능을 보임과 동시에 검색 성능을 보인다. 하지만 FD-tree의 구성 요소 중 하나인 레벨이 하나의 자료구조로만 이루어져 있어 인덱스로서의 비효율성을 가지고 있기 때문에 이를 인덱스의 접근 빈도를 이용하여 개선하고 검색 성능을 높이고자 한다.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.767-774
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• 2010

Due to advantages of NAND flash memory such as non-volatility, low access latency, low energy consumption, light weight, small size and shock resistance, it has become a better alternative over traditional magnetic disk drives, and has been widely used. Traditional DBMSs including mobile DBMSs may run on flash memory without any modification by using Flash Translation Layer (FTL), which emulates a random access block device to hide the characteristics of flash memory such as "erase-before-update". However, most existing FTLs are optimized for file systems, not for DBMSs, and traditional DBMSs are not aware of them. Also, traditional DBMSs do not consider the characteristics of flash memory. In this paper, we propose a flash-conscious storage system for DBMSs that utilizes flash memory as a main storage medium, and carefully put the characteristics of flash memory into considerations. The proposed flash-conscious storage system exploits log records to avoid costly update operations. It is shown that the proposed storage system outperforms the state.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.7
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• pp.1-10
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• 2002

Multidisciplinary Design Optimization (MDO) is a new design approach, which aims to reduce the design cycle and the development cost, while improving the performance of the product. In order to develop a framework software where the multidisciplinary design is possible, several methods about the analysis codes integration, the analysis and optimization process management, and the software architecture, are proposed in this study. Centralized DataBase Management System (DBMS) is adopted. Both the Dynamic Link Library(DLL) and the File Interface are suggested and implemented as analysis codes integration methods. To efficiently manage the optimization process and the data flow, the Graphic Programming approach is introduced. The proposed integration methods are verified by two test case examples: Simple house design example and the aircraft wing design problem using three dimensional Panel Code.

• Journal of Digital Contents Society
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• v.14 no.1
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• pp.15-23
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• 2013

In response to the demands of large-scale data processing with low-power and new application, a storage system using SSD (Solid State Disk/Drive) with fast input-output performance instead of hard disc has appeared as storage device. Studies on methods to overcome specific problems of SSD such as various processing data units, out-place-update and limited delete count have been actively conducted. However, declining performance and stability have not been resolved yet when storing case specific data with small scale that causes frequent random write in hard disc or SSD. This thesis suggests a system structure that stores index requesting frequent random write in NVRAM capable of byte access by using characteristics such as byte unit fast read / write of NVRAM, non-volatile and smaller size of actual changed data size in index page than block size.

• Spatial Information Research
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• v.21 no.3
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• pp.45-53
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• 2013

Web GIS, based on the latest web-technology, has evolved to provide efficient and accurate spatial information to users. Furthermore, Web GIS Server has improved the performance constantly to respond user web requests and to offer spatial information service. This research aims to create a designed and implemented Web GIS Server that is named as Nodemap which uses the emergent technology, Node.js, which has been issued for an event-oriented, non-blocking I/O model framework for coding JavaScript on the server development. Basically, NodeMap is Web GIS Server that supports OGC implementation specification. It is designed to process GIS data by using DBMS, which supports spatial index and standard spatial query function. And NodeMap uses Node-Canvas module supported HTML5 canvas to render spatial information on tile map. Lastly, NodeMap uses Express module based connect module framework. NodaMap performance demonstration confirmed a possibility of applying Node.js as a (next/future) Web GIS Server development technology through the benchmarking. Having completed its quality test of NodeMap, this study has shown the compatibility and potential for Node.js as a Web GIS server development technology, and has shown the bright future of internet GIS service.