• Journal of Communications and Networks
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• v.10 no.4
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• pp.422-429
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• 2008

Mobile peer-to-peer (P2P) systems have recently got in the limelight of the research community that is striving to build efficient and effective mobile content addressable networks. Along this line of research, we propose a new peer-to-peer file sharing protocol suited to mobile ad hoc networks (MANET). The main ingredients of our protocol are network coding and mobility assisted data propagation, i.e., single-hop communication. We argue that network coding in combination with single-hop communication allows P2P file sharing systems in MANET to operate in a more efficient manner and helps the systems to deal with typical MANET issues such as dynamic topology and intermittent connectivity as well as various other issues that have been disregarded in previous MANET P2P researches such as addressing, node/user density, non-cooperativeness, and unreliable channel. Via simulation, we show that our P2P protocol based on network coding and single-hop communication allows shorter file downloading delays compared to an existing MANET P2P protocol.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.395-401
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• 2004

In the current high network-centralized computing and enterprising environment, it is getting essential to transmit data reliably at very high rates. Until now previous client/server model based NFS(Network File System) or AFS(Andrew's Files System) have met the various demands but from now couldn't satisfy those of the today's scalable high-performance computing environment. Not only performance but data sharing service redundancy have risen as a serious problem. In case of NFS, the locking issue and cache cause file system to reboot and make problem when it is used simply as ip-take over for H/A service. In case of AFS, it provides file sharing redundancy but it is not possible until the storage supporting redundancy and equipments are prepared. Lustre is an open source based cluster file system developed to meet both demands. Lustre consists of three types of subsystems : MDS(Meta-Data Server) which offers the meta-data services, OST(Objec Storage Targets) which provide file I/O, and Lustre Clients which interact with OST and MDS. These subsystems with message exchanging and pursuing scalable high-performance file system service. In this paper, we compare the transmission speed of gigabytes file between Lustre and NFS on the basis of concurrent users and also present the high availability of the file system by removing more than one OST in operation.

• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.131-140
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• 2011

File pollution (i.e., sharing of corrupted files, or contaminating index information with bogus index records) is a de facto problem in many file sharing Peer-to-Peer (P2P) systems in use today. Since pollution squanders network resources and frustrates users with unprofitable downloads (due to corrupted files) and unproductive download trials (due to bogus index records), the viability of P2P systems (and similar distributed information-sharing applications) is questionable unless properly addressed. Thus, developing effective anti-pollution mechanisms is an immediate problem in this literature. This paper provides useful information and deep insight with future researchers who want to design an effective anti-pollution mechanism throughout an extensive measurement study of user behavior and file pollution in a representative DHT-based P2P system, the Kad network.

• Journal of the Korea Convergence Society
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• v.9 no.12
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• pp.53-60
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• 2018

With the development of information and communication technology, we have been able to access and manage documents containing corporate information anytime and anywhere using smart devices. As the work environment changes to smart work, the scope of information distribution is expanded, and more efforts are needed to manage security. This paper proposes a file sharing system that enables users who have smart devices to manage and share files through mutual cooperation. Proposed file sharing system, the user can add a partner to share files with each other when uploading files kept by spliting the part of the file and the other uses an algorithm to store on the server. After converting the file to be uploaded to base64, it splits it into encrypted files among users, and then transmits it to the server when it wants to share. It is easy to manage and control files using dedicated application to view files and has high security. Using the system developed with proposed algorithm, it is possible to build a system with high efficiency even for SMEs(small and medium-sized enterprises) that can not pay much money for security.

• Journal of Industrial Technology
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• v.24 no.B
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• pp.193-198
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• 2004

We propose and analyse a flexible secure file sharing scheme which can be used for data sharing among members in P2P environment. When a member wants to share data, notification messages are sent to the members with whom the member wants to share data. Each notification message includes one-time password encrypted with the receiver's public key. A member who received the notification message can download the data by using the one-time password. The proposed scheme provides selective sharing, download confirmation and efficient memory management. In terms of security, the proposed scheme supports authentication, entity privacy, replay attack protection and disguise prevention.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.614-618
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• 2002

Although there are a lot of file sharing mechanisms in the Internet such as NFS and P2P, FTP is one of the most common mechanisms used until now. In this paper, we propose a more enhanced file sharing mechanism, the Distributed File Server (DFS) method. The most remarkable feature of DFS is that it can be simply adopted in the current Internet FTP services by locating a DFS node between existing FTP servers and clients without changing any existing file transfer environment. To verify the proposed mechanism we implemented a DFS prototype on RedHat 7.2 system and we finally show that it can reduce the file storage problem caused by big-sized multimedia data.

• Journal of Information Technology Applications and Management
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• v.16 no.3
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• pp.1-15
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• 2009

The paper analyzes a copyright owning firm's incentive to enforce its copyright in the presence of file-sharing networks. I devise a two-period model where a copyright owner sells two different versions of a creator's information good, and show that the firm's overall profits are enhanced by a strategy of differential inter-temporal enforcement of the copyright protection, compared to strategies of no enforcement or full enforcement in both periods. If the firm enforces no copyright protection in the first period, the low-valuation consumers may make and consume copies that are imperfect substitutes for the original information good. If there is a significant increase in the willingness-to-pay of some low-valuation consumers after they experience the information good, the firm can extract the increased consumer surplus by enforcing a positive level of copyright protection in the second period. Social welfare, however, is maximized in the case of no enforcement.

• International Journal of Computer Science & Network Security
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• v.23 no.2
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• pp.89-95
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• 2023

Cloud computing today provides huge computational resources, storage capacity, and many kinds of data services. Data sharing in the cloud is the practice of exchanging files between various users via cloud technology. The main difficulty with file sharing in the public cloud is maintaining privacy and integrity through data encryption. To address this issue, this paper proposes an Enhanced RSA encryption schema (ERSA) for data sharing in the public cloud that protects privacy and strengthens data integrity. The data owners store their files in the cloud after encrypting the data using the ERSA which combines the RSA algorithm, XOR operation, and SHA-512. This approach can preserve the confidentiality and integrity of a file in any cloud system while data owners are authorized with their unique identities for data access. Furthermore, analysis and experimental results are presented to verify the efficiency and security of the proposed schema.

• The KIPS Transactions:PartA
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• v.16A no.2
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• pp.89-100
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• 2009

With the advance in digital technologies and the increasing prevalence of high quality multimedia contents, there is a growing user demand for multimedia devices, such as mobile phones, digital TV, PMP, digital camcoders, digital cameras. Such devices provide various services associated with multimedia file manipulation, including multimedia contents playback, multimedia file editing, etc. Conventional file systems exhibit a performance-related drawback that requires considerable amount of time and disk I/Os in order to store large-sized edited multimedia files. This paper proposes a fast, efficient writing technique for large-sized edited multimedia files by using data block sharing with adjustment of inode block pointers. Our experiments show that the proposed scheme not only improves write performance of the Ext3 file system on average by 16 times with various types of edited multimedia files, but also reduces consumed disk space dramatically through the data block sharing.

• Journal of KIISE:Information Networking
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• v.37 no.6
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• pp.477-482
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• 2010

Recently, advanced Internet applications such as Internet telephone, multimedia streaming, and file sharing have appeared. Especially, P2P or web-based file sharing applications have been notorious for their illegal usage of contents and massive traffic consumption by a few users. This paper presents a novel method to identify the P2P or web-based file names with traffic monitoring. For this purpose, we have utilized the Korean decoding method on the IP packet payload. From experiments, we have shown that the file names requested by BitTorrent, Clubbox, and Tple applications could be correctly identified.