• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.4
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• pp.240-246
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• 2008

This paper propose a method to enhance the performance of digital contents streaming services with the improve DRM system by maximizing the distribute computing performance and minimizing the overheads of security threatens caused by increasing users and sharing contents in P2P environments. By improving authentication protocols and license protocols to perform decryption and execution simultaneously by only download of the license, streaming services are more enhanced rather than existing DRM systems. For evaluate the performance, this paper compared execution time of existing DRM systems which decrypt the encrypted data file before execute with improved DRM system which execute and decrypt the encrypted data file simultaneously. In experiment, improved DRM system can maintain steady bandwidth and reduce the execution time in compare to existing DRM systems.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.4
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• pp.77-85
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• 2008

PDF is widely accepted as a standard document format and now it supports 3D contents as well. Within the engineering application areas, this new 3D feature may be used to support sharing of 3D documents and thus collaboration between engineering departments, suppliers and partners. In this paper, we describe a system that automatically generates formatted engineering documents including 3D data converted from 3D applications such as commercial 3D CAD viewer. The system consists of two major modules. One is U3D conversion module and the other is PDF conversion module. U3D conversion module extracts geometry, view data, assembly and disassembly information from 3D viewer and converts to U3D format, currently in IDTF text file format. PDF conversion module generates a PDF file and inserts U3D data, various annotation information, and scripts for custom generated operations such as assembly and disassembly in the PDF document.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1204-1211
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• 2004

As the development of information telecommunication technology and thus the information sharing and opening is accelerated, f system is exposed to various threatener and the avrious security incident is rasing its head with social problem. As countermeasure, to protect safely and prepare in the attack for a system from a be latent security threat, various security systems are been using such as IDS, Firewall, VPN etc.. But, expertise or expert is required to handle security system. The module, implemented in this paper, is based on Windows XP, like Linux and Unix, and has effect integrity and non-repudiation for a file.

• Proceedings of the Korean Printing Society Conference
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• 2001.06a
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• pp.63-77
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• 2001

PDF(Portable Document Format) is a file format that Adobe advances postscritp technique and use in managing document information or electric publishing(internet, CD-ROM, DVD). PDF is a devised document type for being able to read and print anywhere, independent of OS, printer type, resolution, and the kind of computer etc. Because this includes a compressing function, it transfers document through a small size of file in internet or intranet. In addition, that is a file format has various advantages-sharing of information and transfering documents in on line or off line environment. In this paper, we developed electronic document system using PDF format. Electronic document system consists of filter, automatic indexing, special searching system and web server. The information used in this paper is database made using Zwon\`s DocuCom. The filter recognizes various kinds of document structure. And according to property of document, it produces ASCII output. In addition to processing various formats of document, the filter can extract keywords in documents of MS WORD, Excel, Powerpoint, PDF, CAD etc. This filter uses the structure of window printer drive and can extract the information for text, page, font type and size from relevant document. The automatic indexing recognizes the formatted tag of document form ASCII text produced by filter and extracts adequate keyword to structure and property of document. PDF electronic document systems proposed in this paper can be used in Internet, PC communication. Users can choose and read electronic documents by two ways. First, users can choose and read relevant books using PDF electronic document homepage. Second, users can use PDF integrated-search system. User can search after inputing keyword and choose reference field and type of data. But, now, PDF products of Adobe can\`t support the Korean character. If this problem is resolved, we thick that PDF applications system looks active. Although there is limited function in case of using Zwon DocuCom used in this study, we think that there isn\`t a great deal of difficulty in electronic document and building digital database.

• Journal of Platform Technology
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• v.6 no.4
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• pp.69-77
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• 2018

In the case of personal information files containing personal information, there is insufficient awareness of personal information protection in end-point areas such as personal computers, smart terminals, and personal storage devices. In this study, we use Diffie-Hellman method to securely retrieve personal information files generated by web crawler. We designed SEED and ARIA using hybrid slicing to protect against attack on personal information file. The encryption performance of the personal information file collected by the Web crawling method is compared with the encryption decryption rate according to the key generation and the encryption decryption sharing according to the user key level. The simulation was performed on the personal information file delivered to the external agency transmission process. As a result, we compared the performance of existing methods and found that the detection rate is improved by 4.64 times and the information protection rate is improved by 18.3%.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.37-45
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• 2015

The technology development of MANET and dissemination of P2P services has been made very widely. In particular, the development of many application services for the integration of P2P services in MANET has been made actively. P2P networks are commonly used because of the advantages of efficient use of network bandwidth and rapid information exchange. In P2P network, the infrastructure managing each node in the middle does not exist and each node is a structure playing a role as the sender and receiver. Such a structure is very similar to the structure of the MANET. However, it is difficult to provide reliable P2P service due to the high mobility of mobile nodes. In this paper, we propose location-based routing technique in order to provide efficient file sharing and management between nodes. GMN managing the group is elected after network is configured to the area of a certain size. Each node is assigned an identifier of 12 bit dynamically to provide routing which uses location information to the identifier. ZGT is managed in the GMN in order to provide management of group nodes and distributed cache information. The distributed cache technique is applied to provide a rapid retrieval of the sharing files in the each node. The excellent performance of the proposed technique was confirmed through experiments.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.1043-1054
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• 2004

The area of business applications in the internet are extended enormously in result of fast development of computing and communication technologies, increase of internet use, and use of intranet/extranet in enterprise information system. In recent days network computing technologies have been developed rapidly and the extended use of Internet applications for enterprises such as intranet/extarnet in and between enterprises has been increased enormously. Therefore the business in the future will be executed by Electronic Commerce based on Business to Business(B2B). <중 략) This paper introduce the design and implementation of the data sharing support system that can be accessed data transparently by the users of participated enterprises in the integrated data environment supporting B2B Electronic Commerce. The system uses Java/CORBA technology in Web environment, relational and object-oriented database system, Object Query Language (OQL) to process the queries of the file information.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.927-928
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• 2016

In the past, the way of sharing data in various devices was to use a physical method such as USBs. The radical development of communications technology and the users, who possess various multimedia devices, caused the need for the new way that people could share their data in various devices, and providing various digital resources by using the cloud computing service helps people solve the limit to sharing the resources in their PC. Therefore, this paper is to suggest the technology for synchronization of mobile devices, and the user-centered cloud service is applied to the technology. Having conducted the experiment, it has been discovered that applying the synchronization of mobile devices using the cloud service enabled to conduct the auto file synchronization and to minimize the bandwidth consumed during the synchronization process between two devices.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.2
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• pp.134-145
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• 2004

With rapid growth in the amount of data transferred on the Internet, traditional storage systems have reached the limits of their capacity and performance. SAN (Storage Area Network), which connects hosts to disk with the Fibre Channel switches, provides one of the powerful solutions to scale the data storage and servers. In this environment, the maintenance of data consistency among hosts is an important issue because multiple hosts share the files on disks attached to the SAN. To preserve data consistency, each host can execute the disk I/O whenever disk read and write operations are requested. However, frequent disk I/O requests cause the deterioration of the overall performance of a SAN cluster. In this paper, we introduce a SANtopia global buffer manager to improve the performance of a SAN cluster reducing the number of disk I/Os. We describe the design and algorithms of the SANtopia global buffer manager, which provides a buffer cache sharing mechanism among the hosts in the SAN cluster. Micro-benchmark results to measure the performance of block I/O operations show that the global buffer manager achieves speed-up by the factor of 1.8-12.8 compared with the existing method using disk I/O operations. Also, File system micro-benchmark results show that SANtopia file system with the global buffer manager improves performance by the factor of 1.06 in case of directories and 1.14 in case of files compared with the file system without a global buffer manager.

• 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.