• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.652-657
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• 2015

BitTorrent is an innovative protocol related to file-sharing and file-transferring, which allows users to receive pieces of files from multiple sharer on the Internet to make the pieces into complete files. In reality, however, free distribution of illegal or copyright related video data is counted for crime. Difficulty of regulation on the copyright of data on BitTorrent is caused by the fact that data is transferred with the pieces of files instead of the complete file formats. Therefore, the classification process of file formats of the digital contents should take precedence in order to restore digital contents from the pieces of files received from BitTorrent, and to check the violation of copyright. This study has suggested SVM classifier for the classification of digital files, which has the feature vector of histogram differential on the pieces of files. The suggested classifier has evaluated the performance with the division factor by applying the classifier to three different formats of video files.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.85-91
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• 2014

Cloud storage system uses a distributed file system for storing and managing data. Traditional distributed file system makes a triplication of data in order to restore data loss in disk failure. However, enforcing data replication method increases storage utilization and causes extra I/O operations during replication process. In this paper, we propose a data replication method using erasure codes in cloud storage system to improve storage space efficiency and I/O performance. In particular, according to data access frequency, the proposed method can reduce the number of data replications but using erasure codes can keep the same data recovery performance. Experimental results show that proposed method improves performance in storage efficiency 40%, read throughput 11%, write throughput 10% better than HDFS does.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.4
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• pp.35-41
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• 2017

This paper introduces a new method for storing a private key. This method can be achieved by dividing the private key into "n" pieces by a (k, n) secret sharing method, and then storing each piece into photo files utilizing a steganography method. In this way, a user can restore a private key as long as he can remember the locations of "k" photos among the entire photo files. Attackers, meanwhile, will find it extremely difficult to extract the private key if a user has hidden the pieces of the private key into numerous photo files stored in the system. It also provides a high degree of user convenience, as the user can restore the private key from his memory of k positions among n photo files. Coupled with this, a certain level of security can be guaranteed because the attacker cannot restore a private key, even if he knows k-1 photo file locations.

• Journal of the Korea Society of Computer and Information
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• v.27 no.12
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• pp.9-16
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• 2022

In this paper, we propose a plan to design and utilize the RDBS(Record Block Data file management System) so that data can be recovered when data files in the Combat Management System are mismatched. The CMS(Combat Management System) manages the same files in multiple IPN(Infomation Processing Node) repositories to support multiplexing. However, mismatches in data files can occur due to equipment maintenance or user immaturity. The existing CMS does not manage the history of changes in data files, and when a mismatch occurs, data file were synchronized based on the latest date. But, It is difficult to say that files with the latest date have the highest reliability, and once the file synchronization has progressed, it cannot be recovered with pre-synchronization data. To solve this problem, data was stored and synchronized in units of record blocks using RDBS proposed in this paper, and the Rsync algorithm was used to reduce the overhead of file synchronization due to units of record blocks. SW applied with RDBS was tested for performance in a simulated environment, and it was confirmed that it could be applied to CMS through normal operation confirmation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.105-110
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• 1998

This paper proposes a method to manage individual information on large scale distributed geographic information systems. On such system, ordinary users usually cannot alter the contents of the server. The method proposed in this paper makes possible to alter the contents or add individual data onto such kinds of non-write-permitted data onto set. We call the method as GDSF, ‘geographic differential script file’. In this method, a client user makes a GDSF which contains the private information to be added onto the served data. Then, the client keeps the file on a local disk. After this, when the user uses the data, he applies the differential data sequence onto the down loaded data to restore the information. The GDSF is a collection of picture commands which tell pictures insertions, deletions, and modification operations. The GDSF also can contain the modification. The GDSF also can contain the modification of the attribute information of geographic entities. The method also applicable to modify data on a ROM device, for example CD-ROM or DVD-ROM. This paper describes the method and experimental results.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.3
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• pp.104-115
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• 2007

As soon as an intrusion is detected by kernel backdoor, the proposed method can be preserve secure and trustworthy evidence even in a damaged system. As an experimental tool, we implement a backup and analysis system, which can be response quickly, to minimize the damages. In this paper, we propose a method, which can restore the deleted log file and analyze the image of a hard disk, to be able to expose the location of a intruder.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.4
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• pp.559-572
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• 2020

As internet technology advances, users can share content online, and many sharing services exist. According to a recently published digital forensic study, when playing an online streaming service, you can restore the played video by reconstructing the Chrome cache file left on local device such as a PC. This can be seen as evidence that the user watched illegal video content. From a different point of view, copyright infringement occurs when a malicious user restores video stream and share it to another site. In this paper, we selected 23 online streaming services that are widely used both at home and abroad. After streaming videos, we tested whether we can recover original video using cache files stored on the PC or not. As a result, the paper found that in most sites we can restore the original video by reconstructing cache files. Furthermore, this study also discussed methodologies for preventing copyright infringement in online streaming service.

• Ocean and Polar Research
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• v.27 no.3
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• pp.311-322
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• 2005

Fisheries buyback programs in Korea have been implemented since 1994, and their scales are estimated to be the present value of 930 billion won for the last 9 yens since 1994. The paper attempts to identify the patterns of each fish species, of which their yields can be steadily increased or significant]y decreased, and to evaluate its effective level and the optimal level for buyback programs by means of fishing capacity analysis. The paper distinguishes fish species, that there is no need to reduce the fishing efforts, such as anchovies, mackerels, squids, Spanish mackerels, and herrings, because MSY exceeds yields, from fish species to control overfishing such as file fish, yellow corvenias, young pollack, hair tail, snow crab, and pollack. The paper also suggests that 65% of the fishing efforts (total tonnages) should be cut back at the national aggregate level in order to restore fish stocks.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.8
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• pp.349-356
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• 2013

As various features of the smartphone have been used, a lot of information have been stored in the smartphone, including the user's personal information. However, a frequent update of the operating system and applications may cause a loss of data and a risk of missing important personal data. Thus, the importance of data backup is significantly increasing. Many users employ the backup feature to store their data securely. However, in the point of forensic view these backup files are considered as important objects for investigation when issued hiding of smartphone or intentional deletion on data of smartphone. Therefore, in this paper we propose a scheme that analyze structure and restore data for Kies backup files of Samsung smartphone which has the highest share of the smartphone in the world. As the experimental results, the suggested scheme shows that the various types of files are analyzed and extracted from those backup files compared to other tools.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.5
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• pp.523-532
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• 2019

Microservice architecture focuses on dividing it into small and lightweight services to build for the purpose of performing very close business functions. So it tends to concentrate only on agility, productivity, reliability, and ease of deployment of software development. Microservice architecture considers database as just a file or storage for storing and extracting data, emphasizing that data quality can be sacrificed for convenience and scalability of software development. Database reverse engineering for understanding database structure and data semantics is needed for data utilization for business decision making. However, it is difficult that reverse database engineering is applied in microservice architecture that neglects data quality. This study proposes database reverse engineering method that utilizes master data to restore the conceptual data model as a solution. The proposed method is applied to the return service database implemented by microservice architecture and verified its applicability.