• International journal of advanced smart convergence
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• v.1 no.1
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• pp.34-37
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• 2012

In a storage system, the performance of data deduplication can be increased if we consider the file modification pattern. For example, if a file is modified at the end of file region then fixed-length chunking algorithm superior to variable-length chunking. Therefore, it is important to predict in which location of a file is modified between files. In this paper, the essential idea is to exploit an efficient file pattern checking scheme that can be used for data deduplication system. The file modification pattern can be used for elaborating data deduplication system for selecting deduplication algorithm. Experiment result shows that the proposed system can predict file modification region with high probability.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.69-74
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• 2006

The recent development of multimedia content-based retrieval technologies brings great attention of musician retrieval using features of a digital audio data among music information retrieval technologies. But the indexing techniques for music databases have not been studied completely. In this paper, we present a musician retrieval technique for audio features using the space split methods in the time-series pattern index file. We use features of audio to retrieve the musician and a time-series pattern index file to search the candidate musicians. Experimental results show that the time-series pattern index file using the rotational split method is efficient for musician retrievals in the time-series pattern files.

• Journal of Korea Multimedia Society
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• v.4 no.6
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• pp.489-499
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• 2001

This paper presents the SIC(Size-Interval-Count) prefetching system that can record the file access patterns of applications within a relatively small space of memory based on the repetitiveness of the file access patterns. The SICPS(SIC Prefetching System) is based on knowledge-based prefetching methods which includes high correctness in predicting future accesses of applications. The proposed system then uses the recorded file access patterns, referred to as "SIC access pattern information", to correctly predict the future accesses of the applications. The proposed prefetching system improved the response time by about 40% compared to the general file system and showed remarkable memory efficiency compared to the previously knowledge-based prefetching methods.

• The KIPS Transactions:PartA
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• v.9A no.2
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• pp.163-170
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• 2002

Previous buffer cache schemes for continuous media file system only exploited the sequentiality of continuous media accesses and didn't consider looping references. However, in some video applications like foreign language learning, users mark the scene as loop area and then application automatically playbacks the scene several times. In this paper, we propose a novel buffer cache scheme for continuous media file system that sequential and looping references exist together. Proposed scheme increases the cache hit ratio by detecting reference pattern of files and appling an appropriate replacement policy to each file.

• Korean Journal of Computational Design and Engineering
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• v.11 no.6
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• pp.440-446
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• 2006

This study relates to the effect of forming time of injection path on the total process. The whole process can be divided into build process of forming path of injection and after treatment process. The total time required for the whole process could be reduced by reducing the forming time of injection path using SLC file to correct the problems of STL file that is the basic file format for high speed molding devices. First of all, I verify the forming time of injection path according to the conditions of STL file during the formation of injection path. And I verify problems using STL file during formation of injection path. And then I tried to solve problems of STL file by comparing between the formation time of injection path and the existing method using SLC files.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.5
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• pp.18-27
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• 2006

Rapid increase of the amount of music data demands for a new method that allows efficient similarity retrieval of music genre using audio features in music databases. To build this similarity retrieval, an indexing techniques that support audio features as a time-series pattern and data mining technologies are needed. In this paper, we address the development of a system that retrieves similar genre music based on the indexing techniques. We first propose the structure of content-based music genre retrieval system based on the time-series pattern index file and data mining technologies. In addition, we implement the time-series pattern index file using audio features and present performance analysis of the time-series pattern index file for similar genre retrieval. The experiments are performed on real data to verify the performance of the proposed method.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.2
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• pp.91-105
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• 2014

This paper proposes a digital forensic method by an evaluation function based on timestamp changing patterns. Operations on file or folder leave changed timestamps, which give the ways to know what operations were executed. Changes of timestamps of ten operations of a file and eight operations of a folder were examined. Analyses on the changes on the eight folder operations are newly added in this paper, which are not performed in the previous works. Based on the timestamps changes of the file and the folder, two evaluation functions are proposed. The first evaluation function checks whether timestamps are changed by file and folder operations, and the second evaluation function checks whether timestamps are originated from a source file or other attribute field. By the two output values from these evaluation functions, a digital forensic investigation on the file or the folder is performed. With some cases, i. e. file copy and folder creation operations, the proposed forensic method is tested for its usefulness.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.12
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• pp.674-684
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• 2001

This paper presents the SIC(Size-Interval-Count) prefetching scheme that can record the file access patterns of applications within a relatively small space of memory based on the repetitiveness of the file access patterns. Several knowledge-based prefetching methods were recently introduced, which includes high correctness in predicting future accesses of applications. They records the access patterns of applications and uses recorded access pattern information to predict which blocks will be requested next. Yet, these methods require to much memory space. Accordingly, the proposed method then uses the recorded file access patterns, referred to as "SIC access pattern information", to correctly predict the future accesses of the applications. The proposed prefetching method improved the response time by about 40% compared to the general file system and showed remarkable memory efficiency compared to the previously knowledge-based prefetching methods.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.275-278
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• 1996

We propose dynamic file allocation method in distributed database management system with changing access patterns. There are a lot of studies on file allocation problem in D-DBMS, and those studies deal with off-line analysis and optimization. Those works are well for systems with static database access patterns, but are inadequate for systems that have changing access patterns. In these systems, dynamic file allocation along with access pattern is more proper. In advance, Brunstrom et al. studied on this area, but they dealt a extremely simplified model. So, we make more practical models to simulate real system. In these models, many factors that were disregard in the advance study are considered. These models are composed with the non-replication system and the replication system. In addition to, we deal with CPU workload balancing in such system in order to improve performance of systems. Our methodology is very simple and realistic, therefore we think that it will give a lot of improvement in D-DBMS with changing access pattern.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.12
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• pp.683-695
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• 2007

NAND flash memory-based file systems cannot store their system-related information in the file system due to wear-leveling of NAND flash memory. This forces NAND flash memory-based file systems to scan the whole flash memory during their mounts. The mount time usually increases linearly according to the size of and the usage pattern of the flash memory. NAND flash memory has been widely used as the storage medium of mobile devices. Due to the fact that mobile devices have unstable power supply, the file system for NAND flash memory requires stable recovery mechanism from power failure. In this paper, we present design and implementation of a new NAND flash memory-based file system that provides fast mount and enhanced stability. Our file system mounts 19 times faster than JFFS2's and 2 times faster than YAFFS's. The stability of our file system is also shown to be equivalent to that of JFFS2.