• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.2
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• pp.49-60
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• 1999

IC 카드의 하드웨어적인 제약으로 대부분의 IC 카드는 대칭키 알고리즘을 사용하고 있지만 IC 카드 하드웨어 제조 기술의 발전으로 앞으로는 보안성이 우수한 비대 칭키 알고리즘이 많이 사용될 것이다. 그리고 IC 카드의 가장 큰 제약적 중 하나는 메모리 용량의 한계이다. 따라서 보안상 안전하면서도 메모리를 적게 사용하는 IC 카드 운영체제의 구현을 중요한 문제이다. 그래서 본 논문에서는 다양한 종류의 키 알고리즘을 수용할 수 있는 키 파일 탐색 기법을 제안하였다. 또한 데이터 파일 헤더에 잠금 필드를 삽입하여 보안성을 향상시켰으며 메모리 사용량을 줄일 수 있도록 데이터 파일 헤더만을 이용한 파일 탐색 기법과 자유 공간 탐색 기법을 제안하였다. Because of the evolution of IC card hardware fabrication technologies IC card will be able to accept asymmetric key encryption algorithm in the future. One of the most restrictive points of IC card is memory capacity. Therefore it is an important problem to design a secure IC card operating system using memory in small. In this paper we proposed a key file search mechanism using a key length field inserted in a key file header structure. The key file search mechanism makes IC card execute any key-based encryption algorithm. In addition we proposed inserting a lock field in data file header structure. The lock field intensifies the security of a data file. Finally we proposed a data file search mechanism and free space search mechanism using only data file header. The file system using these mechanisms spends smaller memory than that using a file description table and record of unallocated space.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.11
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• pp.140-147
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• 1995

This paper deals with conversion from the STL file to the Slice to the Slice cross-sectional information for Stereolithography. The STL file is widely used for Stereolithography, but it is very difficult to convert STL file into Slice file directly. Because it consists of an ordered list of triangular net without any topological information other than the orientation of each facet. So, The system is accomplished by data flow through several intermediate stages such as Reference. SL1. .SL2L. .SL3. and .SLC file. The data processing is performed in 5 steps: 1) Create a Reference file including common information. 2) Modify STL file within the effective range of SL machine. 3) Calculate a point of intersection between plane equation and line equation. 4) Sort z values in ascending order using quick sort algorithm. 5) Search the adjacent points and formulate a closed loop usingsingly linked linear list. The system is developed by using Borland C++ 3.1 compiler in the environment of Pentium PC, and verified to be satisfactory by making some prototypes of electric household appliances.

• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.275-282
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• 2006

There are several independent applets to support various applications in a Java Card. Each applet in a Java Card processes and manages its own data without concern to other applets and their data. In this paper we proposed file system API to support efficient file management based on Java Card. Also we designed and implemented Java Card based file system API using basic API and referring to the file system standard defined in ISO 7816-4 Smart Card standard. By using proposed file system API, we can replace duplications of same code in each applet with short method call. So the used memory space and processing time is reduced and also the reduction of development time and cost will be expected.

• The KIPS Transactions:PartA
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• v.13A no.3 s.100
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• pp.241-252
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• 2006

In cluster file systems, the availability of files has been supported by replicating entire files or generating parities on parity servers. However, those methods require very large temporal and spatial cost, and cannot handle massive failures situation on the file system. So we propose HA-PVFS, a cluster file system supporting high data availability adaptive to temporal locality. HA-PVFS restricts replication or parity generation to some important files, for that it employs an efficient algorithm to estimate file access patterns from limited information. Moreover, in order to minimize the performance degradation of the file system, it uses delayed update method and relay replication.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.3
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• pp.181-190
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• 2013

In this paper, we designed file system in order to utilize data analysis by using correlation result from Daejeon correlator including related software development. Correlation results are consisted of visibility component (amplitude and phase) of radio source, but for data analysis of correlation result, various information such as weather, radio telescope position, observation time, radio source position, source type, and receiver noise temperature are needed. In this paper, we designed file system as a directory-structure for making use of these informations at Linux system for analyzing data and developed software to make file system. To verify the effectiveness of designed file system and developed software, file system generation experiment is conducted, and then astronomers accepted that there is no severe problem for scientific analysis using designed file system.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.4
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• pp.368-380
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• 2005

File systems for flash memory that is widely used as a storage device for mobile devices should provide not only high-performance data reads and writes but also a guarantee on the data integrity even on a power failure. In this paper, we explain the design and implementation of a file system for flash memory that considers flash memory's physical characteristics and the data layout in the file system to give an optimized write performance. This file system guarantees the reliability against various system failures including a power failure by using the transaction concept in write processing. In addition, the file system minimizes the memory usage by using a simple static mapping. In the paper, we also describe the implementation of the file system and compare its performance with other existing flash memory ille systems.

• Journal of Internet Computing and Services
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• v.6 no.4
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• pp.47-58
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• 2005

There are two major type of flash memory products, namely, NAND-type and NOR-type flash memory. NOR-type flash memory is generally deployed as ROM BIOS code storage because if offers Byte I/O and fast read operation. However, NOR-type flash memory is more expensive than NAND-type flash memory in terms of the cost per byte ratio, and hence NAND type flash memory is more widely used as large data storage such as embedded Linux file systems. In this paper, we designed an efficient flash memory file system based an Embedded system and presented to make up for reduced to Swapping a weak System Performance to flash file system using NAND-type flash memory, then proposed Swapping algorithm insured to an Execution time. Based on Implementation and simulation studies, Then, We improved performance bases on NAND-type flash memory to the requirement of the embedded system.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.182-190
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• 2005

As computers and Internet become popular, many corporations and countries are using information protection system and security network to protect their informations and resources in internet. But the Intrusional possibilities are increases in open network environments such as the Internet. Even though many security systems were developed, the implementation of these systems are mostly application level not kernel level. Also many file protection systems were developed, but they aren't used widely because of their inconvenience in usage. In this paper, we implement a kernel module to support a file protection function using Loadable Kernel Module (LKM) on Linux. When a system is damaged due to intrusion, the file system are easily recovered through periodical file system image backup.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.40
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• pp.169-178
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• 1996

Geographically dispersed computing system is made of computers interconnected by a telecommunications network. To make the system operated efficiently, system designer must determine the allocation of data files to each node. In designing such distributed computing system, the most important issue is the determination of the numbers and the locations where database files are allocated. This is commonly referred to as the file allocation problem (FAP)[3]. The proposed model is a 0/l integer programming problem minimizing the sum of file storage costs and communication(query and update) costs. File allocation problem belongs to the class of NP-Complete problems. Because of the complexity, it is hard to solve. So, this paper presents an efficient heuristic algorithm to solve the file allocation problem using Tabu Search Technique. By comparing the optimal solutions with the heuristic solutions, it is believed that the proposed heuristic algorithm gives good solutions. Through the experimentation of various starting points and tabu restrictions, this paper presents fast and efficient method to solve the file allocation problem in the distributed computing system.

• Journal of Information Processing Systems
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• v.2 no.3 s.4
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• pp.147-152
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• 2006

NAND flash memory-based embedded systems are becoming increasingly common. These embedded systems have to provide a fast boot time. In this paper, we have designed and proposed a flash file system for embedded systems that require fast booting. By using a Flash Image Area, which keeps the latest flash memory information such as types and status of all blocks, the file system mounting time can be reduced significantly. We have shown by experiments that our file system outperforms YAFFS and RFFS.