• The Transactions of the Korea Information Processing Society
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• v.4 no.2
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• pp.325-337
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• 1997

This paper introduces the basic concepts and requirements of database system based on the object-oriented paradigm,and presents the overview of the design of an object-oriented data base system which refects those conceprs and requirements . The system imolemented on C++,consists of three structure layers.The inner layer, which is in fact a storage system,performs file I/O,while the inermediate layer is responisible for most of the functions except the ones rerated to the user interface, such as the transaction management,the schema manage-ment,and the management of buffers in main memory etc.The outer layer,designed mainly for the uwerunteface,mot only privides the functions for graphical user interface,preprocessor,and interpreter etc,but also supports extended SQL for object-oriented features.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.221.1-221.1
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• 2012

The Korea Astronomy and Space Science Institute (KASI) is developing three 1.6m optical telescopes with $18k{\times}18k$ mosaic CCD cameras. These telescopes will be installed and operated at Chile, South Africa, and Australia for Korea Micro-lensing Telescope Network (KMTNet) project. The main scientific goal of the project is to discover earth-like extra-solar planets using the gravitational micro-lensing technique. To achieve the goal, each telescope at three sites will continuously monitor the specific region of Galactic bulge with 2.5 minute cadence for five years. Assuming 12 hour observation in maximum for a night, the amount of 200 GB file storage is required for one night observation at one observatory. If we consider the whole project period and the data processing procedure, a few PB class data storage, high-speed network, and high performance computers are essential. In this presentation, we introduce the KMTNet data management plan that handles gigantic data; raw image collecting, image processing, photometry pipeline, database archiving, and backup.

• Spatial Information Research
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• v.14 no.4 s.39
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• pp.379-389
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• 2006

Map databases for CNS (Car Navigation System) can be accessed quickly and compressed efficiently due to that these are usually recorded as in a PSF (Physical Storage Format). However, it is difficult to create and manage data storage based on a file-system. To solve these problems, DBMS needs to be combined with spatial data management. Therefore, we developed an embedded DBMS with which to store data and conduct quick searches in CNS. Spatial data could be easily managed and accessed using the compression method, Multi-Link, spatial index, and spatial division. In the result, the proposed embedded DBMS searched quickly and stably supported data management. If synchronization is applied in DBMS, it is expected to utilize the advantages of an embedded DBMS.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.4 s.316
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• pp.27-34
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• 2007

In this paper device driver for camera capture in hand held mobile system is implemented based on microsoft windows CE operating system. We also study the storage device driver based on the FAT fie system by using NAND flash memory as a storage device. We use the MBA2440 PDA board for implementing the hardware for image capture by using CMOS camera module producted by PixelPlus company. This camera module has VGA $640{\times}480$ pixel resolution. We also make application program which can be cooperated with the device driver for testing its performance, for example image capture speed and quality of captured image. We check that the application can be cooperated well not only with the device driver for camera capture but also with the device driver for FAT file system designed especially for the NAND flash memory.

• Spatial Information Research
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• v.19 no.6
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• pp.87-100
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• 2011

Recently, a variety of GML application schemas have been designed in many fields. GML application schemas are specific to the application domain of interest and specify object types using primitive object types defined in the GML standard. GML instance documents are created based on such GML application schemas. The GML instance documents generally require large volumes to represent huge amounts of geographic objects. Thus, it is essential to store such GML instance documents in relational database for efficient management and use. Relational database is relatively convenient to use and is widely applied in various fields. Furthermore, it is fundamentally more efficient than file structure to handle large datasets. Many researches on storing GML documents have been carried out so far. However, there are few studies on storage of GML instance documents. Therefore, in this study, we developed the storage module to store the GML instance documents in relational database.

• Journal of Information Processing Systems
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• v.14 no.4
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• pp.989-1009
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• 2018

Rapid advances in science and technology with exponential development of smart mobile devices, workstations, supercomputers, smart gadgets and network servers has been witnessed over the past few years. The sudden increase in the Internet population and manifold growth in internet speeds has occasioned the generation of an enormous amount of data, now termed 'big data'. Given this scenario, storage of data on local servers or a personal computer is an issue, which can be resolved by utilizing cloud computing. At present, there are several cloud computing service providers available to resolve the big data issues. This paper establishes a framework that builds Hadoop clusters on the new single-board computer (SBC) Mobile Raspberry Pi. Moreover, these clusters offer facilities for storage as well as computing. Besides the fact that the regular data centers require large amounts of energy for operation, they also need cooling equipment and occupy prime real estate. However, this energy consumption scenario and the physical space constraints can be solved by employing a Mobile Raspberry Pi with Hadoop clusters that provides a cost-effective, low-power, high-speed solution along with micro-data center support for big data. Hadoop provides the required modules for the distributed processing of big data by deploying map-reduce programming approaches. In this work, the performance of SBC clusters and a single computer were compared. It can be observed from the experimental data that the SBC clusters exemplify superior performance to a single computer, by around 20%. Furthermore, the cluster processing speed for large volumes of data can be enhanced by escalating the number of SBC nodes. Data storage is accomplished by using a Hadoop Distributed File System (HDFS), which offers more flexibility and greater scalability than a single computer system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1531-1539
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• 2017

The existing SSD storage tester processed logs in a 1-N structure between server and client using TCP and network file system. This method causes some problems for example, an increase in CPU usage and difficulty in exception handling, etc. In this paper, we implement a log processing message layer that can deal with asynchronous distributed processing using open source messaging system such as kafka, RabbitMQ and compare this layer with existing log transmission method. A log simulator was implemented to compare the transmission bandwidth and CPU usage. Test results show that the transmission using the message layer has higher performance than the transmission using the message layer, and the CPU usage does not show any significant difference The message layer can be implemented more easily than the conventional method and the efficiency is higher than that of the conventional method.

• KIISE Transactions on Computing Practices
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• v.21 no.10
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• pp.639-644
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• 2015

The capacity of flash-based storage such as Solid State Drive(SSD) and embedded Multi Media Card(eMMC) is ever-increasing because of the needs from the end-users. However, if a flash-based storage crashes, such as during power failure, the flash translation layer(FTL) is responsible for the crash recovery based on the entire flash memory. The recovery time increases as the capacity of the flash-based storages increases. We propose O1FTL with O(1) crash recovery time that is independent of the flash capacity. O1FTL adopts the working area technique suggested for the flash file system and evaluates the design on a real hardware platform. The results show that O1FTL achieves a crash recovery time that is independent of the capacity and the overhead, in terms of I/O performance, and achieves a low P/E cycle.

• Journal of the Korean Society for information Management
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• v.40 no.1
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• pp.149-173
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• 2023

This study examines email records management patterns of undergraduate students and their perceptions of university email policy. The research collected data from 317 undergraduate students using a survey based on the five essential elements of email records management: common elements, email creation, email management, email preservation, and perception. Also, an in-depth interview was conducted with 6 undergraduate students, according to the method of university email service: Google, Microsoft, and in-house webmail. As a result, undergraduate students used email as an address book, cloud storage, file storage, and collaboration tool, and they had difficulties in systematically managing the email records according to the records lifecycle. Also, there was a tendency to prefer using an external email platform that can use additional functions to in-house webmail that has limitations in mobile service and preservation of attachments. Thus, this study suggests ways to help undergraduate students manage their email records, including maintaining graduates' email accounts, providing sufficient email storage, and providing email records management training and guidelines for undergraduate students.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.4 no.2
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• pp.34-44
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• 1986

A data base system for a minicomputer, designed on the basis of the concept of Relational model, is proposed in this thesis. It is a module of reentrant programs, which can serve multi-users concurrently and interactivelv. Relational calculus is chosen as a data sublanguage. The inverted-list file structure is used for the physical storage structuse with the technique of seperating data and their relationships, while data model records, which contain the information of the logical data organization and linkage to a physical structure, con struct the data model. The retrieval is performed mainly with these.