• Convergence Security Journal
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• v.8 no.3
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• pp.1-8
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• 2008

The pattern matching part of Intrusion Detection System based on misuse-detection mechanism needs much processing time and resources, and it has become a bottleneck in system performance. Moreover, it derives denial-of-service attack. In this paper, we propose (1) framework architecture that is strong against denial-of-service attack and (2) efficient pattern matching method especially for web server system. By using both of these 2 methods, we can maintain web server system efficiently secure against attacks including denial-of-service.

• Journal of the Korea Computer Industry Society
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• v.3 no.5
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• pp.653-660
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• 2002

In this paper, we designed and implemented an Internet Geographic Information System, called IGIS, that supports the client/server architecture connected via the Internet. IGIS is consists of the Map Server and the Map Viewer which can be located at a server site and client sites, respectively. In addition, we used the Common Gateway Interface(CGI) to service the geographic information on the Internet and used a DXF(Data eXchange Format) file as a geographic data in IGIS.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06a
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• pp.321-322
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• 2008

• Journal of Korean Society for Geospatial Information Science
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• v.8 no.1 s.15
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• pp.43-49
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• 2000

In this paper, we designed and implemented an Internet Geographic Information System called IGIS, that supports the client/server architecture connected via the Internet. IGIS is consists of the Map Server and the Map Viewer which can be located at a server site and client sites, respectively. In addition, we used the Common Gateway Interface(CGI) to service the geographic information on the Internet and used a DXF(Data exchange Format) file as a geographic data in IGIS.

• Journal of Internet Computing and Services
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• v.6 no.2
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• pp.69-84
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• 2005

As the Internet users are increasing rapidly, a cluster web server system is attracted by many researchers and Internet service providers. The cluster web server has been developed to efficiently support a larger number of users as well as to provide high scalable and available system. In order to provide the high performance in the cluster web server, efficient load distribution is important, and recently many content-aware request distribution techniques have been proposed. In this paper, we propose a new content-aware load balancing technique that can evenly distribute the workload to each node in the cluster web server. The proposed technique is based on the hash histogram transformation, in which each URL entry of the web log file is hashed, and the access frequency and file size are accumulated as a histogram. Each user request is assigned into a node by mapping of (hashed value-server node) in the histogram transformation. In the proposed technique, the histogram is updated periodically and then the even distribution of user requests can be maintained continuously. In addition to the load balancing, our technique can exploit the cache effect to improve the performance. The simulation results show that the performance of our technique is quite better than that of the traditional round-robin method and we can improve the performance more than $10\%$ compared with the existing workload-aware load balancing(WARD) method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.14-19
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• 2007

As XML is used by standard format for information expression and information exchange in various field, Many Company began to use SVG by user interface or information expression tool of embedded system such as mobile phone based wireless internet. Because SVG has many additional information to keep structure of SVG document exception real data, there is a problem that transfer time of SVG file is so cost for quantity of transmitted data actually. To solve this problem, many researches using compression conception have been conducted for applying to an embedded system. This paper proposes SMETA that can use existing researches using compression concept at once. SMETA divides SVG file to each part that can allocate meaning, and gives semantic metadata to each part without alteration of SVG structure. SMETA can reduce site of transmitted SVG file actually by transmitting specification part of SVG file that metadata does not agree or has unlisted part in an embedded system between an embedded system and server, before transmit whole SVG file. By size of transmitting SVG file is decreasing, transfer time can be shortened accordingly.

• Journal of Information Processing Systems
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• v.16 no.2
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• pp.301-317
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• 2020

An enterprise patch-management system (PMS) typically supplies a single point of failure (SPOF) of centralization structure. However, a Blockchain system offers features of decentralization, transaction integrity, user certification, and a smart chaincode. This study proposes a Hyperledger Fabric Blockchain-based distributed patch-management system and verifies its technological feasibility through prototyping, so that all participating users can be protected from various threats. In particular, by adopting a private chain for patch file set management, it is designed as a Blockchain system that can enhance security, log management, latest status supervision and monitoring functions. In addition, it uses a Hyperledger Fabric that owns a practical Byzantine fault tolerant consensus algorithm, and implements the functions of upload patch file set, download patch file set, and audit patch file history, which are major features of PMS, as a smart contract (chaincode), and verified this operation. The distributed ledger structure of Blockchain-based PMS can be a solution for distributor and client authentication and forgery problems, SPOF problem, and distribution record reliability problem. It not only presents an alternative to dealing with central management server loads and failures, but it also provides a higher level of security and availability.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.1
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• pp.8-18
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• 2010

Traditional storage server suffers from duplicated data blocks which cause an waste of storage space and network bandwidth. To address this problem, various de-duplication mechanisms are proposed. Especially, lots of works are limited to backup server that exploits Contents-Defined Chunking (CDC). In backup server, duplicated blocks can be easily traced by using Anchor, therefore CDC scheme is widely used for backup server. In this paper, we propose a new de-duplication mechanism for improving a storage system. We focus on efficient algorithm for supporting general purpose de-duplication server including backup server, P2P server, and FTP server. The key idea is to adapt stride scheme on traditional fixed block duplication checking mechanism. Experimental result shows that the proposed mechanism can minimize computation time for detecting duplicated region of blocks and efficiently manage storage systems.

• Journal of Korea Multimedia Society
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• v.21 no.3
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• pp.358-368
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• 2018

The mobile characteristics of the smart phone are well suited to on-the-site oriented services and are being utilized in a variety of ways. However, since most applications operate on a central server basis, Internet access is inevitable, and there are various problems such as an increase in server maintenance cost and security deterioration. Although researches have been proposed to utilize the smart phone itself as a server to improve it, these methods are based on downsizing the PC-based web server or modifying the smart phone kernel. These methods have the problems that a end user has to use the rooting, and they are not able to effectively utilize various communication means of a smart phone. In this paper, we propose a design and implementation of an application level smart phone web server. The server receives the document request from the remote via the Internet and in the local area using the WPAN. At this time, the web document is stored as an internal file structure of the smart phone application. We proposed the phttp protocol which uses server's phone number as ID for document request. Through the implementation, we analyzed the capacity and latency of stored data and its effectiveness is evaluated.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.223-232
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• 2017

Previous research on data recovery in Microsoft SQL Server has focused on restoring data based on in the transaction log that might have deleted records exist. However, there was a limit that was not applicable if the related transaction log did not exist or the physical database file was not connected to Server. Since the suspect in the crime scene may delete the data records using a different deletion statements besides "delete", we need to check the remaining data and a recovery possibility of the deleted record. In this paper, we examined the changes "Page Allocation information" of the table, "Unallocation deleted data", "Row Offset Array" in the page according to "delete", "truncate" and "drop" events. Finally it confirmed the possibility of data recovery and availability of management tools in Microsoft SQL Server digital forensic investigation.