• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.4
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• pp.234-241
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• 2014

xTo improve network inefficiency caused by network congestion around a content-source, content-centric networking (CCN) allows network nodes transmitting contents to temporarily cache received contents and then send back the cached contents if the nodes receive relevant request messages without forwarding the request messages to content-sources. However, because nodes receiving requested contents through CCN cannot recognize real senders of the received contents, the receivers need to verify each received contents before using them. But such a verification procedure can cause long service/operation delay. Hence, in this paper, we review the problem of contents verification, propose an improved verification procedure and evaluate its performance.

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.149-155
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• 2004

This paper describes the self-adaptive Content Service Network (CSN) on Application Level Active Network (ALAN). Web caching technology comprises Content Delivery Network (CDN) for content distribution as well as Content Service Network (CSN) for service distribution. The IETF working group on Open Pluggalble Edge Service (OPES) is the works closely related to CSN. But it can be expected that the self-adaptation in ubiquitous computing environment will be deployed. The existing content service on CSN lacks in considering self-adaptation. This results in inability of existing network to support the additional services. Therefore, in order to address the limitations of the existing networks, this paper suggests Self-adaptive Content Service Network (CSN) using the GME and the extended ALAN to insert intelligence into the existing network.

• The KIPS Transactions:PartA
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• v.11A no.2
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• pp.175-180
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• 2004

Generally, as for the multimedia high quality contents, an illegality facsimile is possible without a damage of a quality. Also a distribution of contents duplicated illegality in an Internet is giving a great economic loss to digital contents provider. Therefore, a study for security and efficient distribution of digital contents is required. The most important issues in a design of digital contents distribution system are a user convenience, an execution speed and a security. In this study, we designed digital contents distribution system that used a web caching technology and an encryption/decryption technique on hierarchical structure. The proposed system was the digital contents distribution system that improved a security and execution speed, a convenience of a user. Also it verified performance superiority of a proposed system by an examination.

• Journal of the Korea Society of Computer and Information
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• v.29 no.7
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• pp.109-115
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• 2024

Overleaf is a cloud-based LaTeX editor, allowing users to easily create and collaborate on documents without the need for separate LaTeX installation or configuration. Thanks to this convenience, users from various fields worldwide are writing, editing, and collaborating on academic papers, reports, and more via web browsers. However, the caching that occurs during the process of converting documents written on Overleaf to PDF format poses risks of exposing sensitive information. This could potentially lead to the exposure of users' work to others, necessitating the implementation of security measures and vigilance to caution against such incidents. This paper delves into an in-depth analysis of Overleaf's security vulnerabilities and proposes various measures to enhance the protection of intellectual property.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.5
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• pp.365-373
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• 2013

Tile caching technology is a commonly used method that optimizes the delivery of map imagery across the internet in modern WebGIS systems. However the poor performance of the map tile cache update is one of the major causes that hamper the wider use of this technique for datasets with frequent updates. In this paper, we introduce a new algorithm, namely, Partial Area Cache Update (PACU) that significantly minimizes redundant update of map tiles where the update frequency of source map data is very large. The performance of our algorithm is verified with the cadastral map data of Pyeongtaek of Gyeonggi Province, where approximately 3,100 changes occur in a day among the 331,594 parcels. The experiment results show that the performance of the PACU algorithm is 6.6 times faster than the ESRI ArcGIS SERVER$^{(r)}$. This algorithm significantly contributes in solving the frequent update problem and enable Web Map Tile Services for data that requires frequent update.

• Journal of Internet Computing and Services
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• v.6 no.4
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• pp.59-73
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• 2005

Caching query results and reusing them in processing of subsequent queries is an important query optimization technique. Materialized view and view indexing are the representative examples of such a technique. The two schemes had received much attention for relational databases, and have been investigated for XML data since XML emerged as the standard for data exchange on the Web. In XML view indexing, XML view xv which is the result of an XML query is represented as an XML view index(XVI), a structure containing the identifiers of xv's underlying XML elements as well as the information on xv. Since XVI for xv stores just the identifiers of the XML elements not the elements themselves, when xv is requested, its XVI should be materialized against xv's underlying XML documents. In this paper, we address the problem of integrating an XML view index management system with an RDBMS based XML storage system. The proposed system was implemented in Java on Windows 2000 Server with each of two different commercial RDBMSs, and used in evaluating performance improvement through XML view indexing as well as its overheads. The experimental results revealed that XML view indexing was very effective with an RDBMS based XML storage system while its overhead was negligible.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.7
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• pp.384-393
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• 2002

A Parallel file system is normally used to support excessive file requests from parallel applications in a cluster system, whereas prefetching is useful for improving the file system performance. This paper proposes a new prefetching method, Fips(dynamic File Prefetching Scheme based on file access patterms), that is particularly suitable for parallel scientific applications and multimedia web services in a parallel file system. The proposed prefetching method introduces a dynamic prefetching scheme to predict data blocks precisely in run-time although the file access patterns are irregular. In addition, it includes an algorithm to determine whether and when the prefetching is performed using the current available I/O bandwidth. Experimental results confirmed that the use of the proposed prefetching policy in a parallel file system produced a higher file system performance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.4
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• pp.839-847
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• 2015

To seamlessly provide content through the Internet, it is generally considered to use distributed processing for content requests converged on original content providers like P2P, CDN, and ICN. That is, after other nodes temporally save content, they handle content requests instead of original content providers. However, in this case, it may be possible that a content sender is different from the original provider of the content. In this case, users may be exposed to various risks. To solve such a problem, it is highly recommended to verify received contents before using them, but it can cause network traffic increases as well as a serious service delay. This paper proposes an efficient content verification scheme for distributed networking/data store environments and analyzes its performance.

• Journal of KIISE:Databases
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• v.33 no.5
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• pp.551-562
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• 2006

XML query caching for XML database-backed Web applications began to be investigated recently. Despite its practical significance, efficiency of the storage schemes for cached query results has not been addressed. In this paper, we deal with the storage schemes for XML query cache. A fundamental problem that needs to be considered in designing an efficient storage structure for XML query cache is that there exist performance tradeoffs between the two major types of operations on a cached query result. The two are (1) retrieving the whole of it to return the query result and (2) updating just a small portion of it for its incremental refresh against the updates done to its source. We propose eight different storage schemes for XML query cache, which are categorized into three groups: (1) the schemes based on the plain text file, (2) the schemes based on the persistent DOM (PDOM) file, and (3) a scheme employing an RDBMS. We implemented all of them, and compared their performance with each other. We also compared our proposal with a storage scheme based on a current state-of-the-art XML storage scheme, showing that ours is more efficient.

• The KIPS Transactions:PartB
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• v.11B no.3
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• pp.361-368
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• 2004

This paper proposes an interactive VOD system to serve truly interactive VCR services using multicast delivery, client buffer and web-caching technique which implements the distributed proxy in Head-End- Network(HNET). This technique adopts some caches in the HNET that consists of a Switching Agent(SA), some Head-End-Nodes(HEN) and many clients. In this model, HENs distributively store the requested video under the control of SA. Also, client buffer dynamically expands to support various VCR playback rate. Thus, interactive services are offered with transmitting video streams from network, HENs and stored streams on buffer. Therefore this technique makes the load of network occur In the limited area, minimizes the additional channel allocation from server and restricts the transmission of duplicated video contents