• 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.

• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.33-38
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• 2003

Most of the existing algorithms try to disseminate the multimedia contents of internet service provider (ISP), without taking into account characteristics and capacities of duplicated servers. However, they are less reliable without prior information on capacities of duplicated servers. In this paper we propose two algorithms, performance rating algorithm of hardware and capacity algorithm, inspired by the need of improving QoS of delivering multimedia contents without incurring long access delays when the capacities of duplicated servers are significantly different and clients locate in a fixed geographical domain Our simulation results show that they are better than HTTP response time algorithm when the multimedia contents are large and quite different from performances between duplicated servers.

• ETRI Journal
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• v.10 no.4
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• pp.89-98
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• 1988

We consider an N duplicate-server system, where each server consists of two reconfigurable duplicated units which are subject to breakdowns. This system is studied analytically using generating functions, and also numerically using the matrix-geometric procedure. Using the generating function approach we obtain a recursive expression of the queuelength distribution for N=1. This expression in difficult to generalize to N>1. The numerical method is applicable for any value of N. For any N, we also obtain the condition for stability and the availability of the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.63-71
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• 2014

In this paper we researched on the Duplication Techniques for Active-Active Web Servers. Rsync and crontab utilities make copy periodically between web servers and maintain the same status. Load Balancing Server makes web servers load balanced and fast servicing by executing web servers alternatively. Even though one web server stops due to some critical errors, the remaining web server can take over and provide services continuously.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.5
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• pp.439-450
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• 1987

Data, distributed and/or duplicated among multiple computers interconnected by a LAN, need to be managed consistently and accessed transparently by users. A command/file server, named UTP, which meets the preceding needs was developed for supermini-computers which are interconnected by an Ethernet-based LAN and run under UNIX OS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.7
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• pp.1361-1373
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• 2001

In the firewall systems of 3-tier client/server systems, in general, data transmission speed is declined rapidly according to the duplicated proxy services in application server and fire wall server. In this paper, an application server configuration containing the proxy functions of firewall system is proposed so that the high speed data transmission can be achieved. The proposed application server can form the dual-homed gateway by means of the additional network interface card. The screened router of application server forms the screened subnet gateway that can separate the internal network. The proposed server configuration is more effective in traffic control than the traditional firewall systems and provides high speed data transmission with the functions of firewall. It can be also cost-effective alternative to the firewall system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.11
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• pp.2869-2885
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• 1996

There werer many researches on the switch system for high speed netowrk such as B-ISDN and the server system for the multimedia services respectively. But, in case of simple connection of these two systems, we have to suffer the bottlenck problem of data transmission, and pay the wasteful expenditure because of duplicated architecture of both systems such as interconnecting network at the switch and the server. Therefore, we propse the unified architecture of switehces and servers, which can be used as switches and servers simultaneously. This is based on the hybercube structure. The links are used iterconnection network of switch system, and each node has the subscriber subsystem and the server subsystem. The proposed architecure has the benifits as follows; the easy espansion of capacity due to the scalability,the simple system development and maintenance because of the equivalance of each nodes, the high reliability against the fault of nodes and links due to the existence of the many alternative links between nodes, the easy flow and QoS managment due to the non-blocking data transmission between any two nodes, the flexible adaptation for additional new services owing to simple insertion server board to node. In this paper, we present overal configuration and node component of proposed architecture, and the procesing flow for the various services.

• Journal of Korea Game Society
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• v.14 no.5
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• pp.107-116
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• 2014

The traditional methodology of online game development is separating server development module and cilent development module. However developing and maintaining expenses have been increased a lot due to duplicated modules such as definitions of network protocols and managements of planning data. In this paper, we suggest an advanced methodology of online game development based on the integrated single module with client and server. Its effectiveness was shown by applying the proposed methodology in the development of the online game 'Chungmukong's Battle on the Sea'. In this case, the project size was reduced by 15.1% by using the integrated single module with client and server.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.659-672
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• 2004

A Mobile Ad hoc Network (MANET) is a group of independent mobile computing nodes that consist of a multi-hop wireless network without a central administration or any infrastructure. Every node that wants to join a MANET must obtain an address for communication. Having a centralized DHCP server that provides addresses to nodes, we can easily and automatically obtain addresses. However, a MANET lacks any fixed infrastructure such as a DHCP server. We therefore propose a distributed address autoconfiguration approach for a MANET using a reserved address and optimistic Duplicated Address Detection (DAD). The reserved address helps to reduce the allocation latency, and the optimistic DAD guarantees the uniqueness of addresses and lessens communication overhead. We then suggest methods of handling network partition and network merging situations, and go on to evaluate our approach through simulations. The simulation result shows that our scheme guarantees the uniqueness of allocated address and considerably improves allocation latency and communication overheads.

• Spatial Information Research
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• v.9 no.2
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• pp.353-368
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• 2001

Recently central and local governments developed a huge spatial database and system using full-scale Geographic Information System (GIS). But Inconsistent spatial data through duplicated database management drops off in efficiency and confidence of administration. It is difficult to share data because of their unique system and data type. Under these circumstances Ministry of Construction and Transportation (MOCT) has been carrying out Land Management Information System (LMIS) to computerize land administration and policy affairs and to implement land database such as law, spatial, attribute data. A prerequisite mission of LMIS is to develop open system for solving the problem of duplicated data management and data sharing and for supporting various computer environments such as hardware, software, network etc. The purpose of LMIS is to reuse the existing investment resources and to expand the existing system resources. Therefore the purpose of this study is to investigate a method of LMIS operation under the existing circumstances and expansion of the system in the future. To do this, Supporting various DBMS, GIS server, Distributing Computing Platform(Unix, NT Server) is needed. Especially LMIS need to be developed as open system with interoperability to get independence of application from various GIS servers.