• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.4
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• pp.95-105
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• 2010

DNS(Domain Name System) is a huge distributed database that converts host name to IP address. We are expecting the importance of DNS is more increased because many Internet application services appear according to the continuous increase of Internet users and nearly all the Internet application services use DNS. To prevent the interruption of DNS service, DNS server is configured with primary DNS server and a secondary DNS server which takes the place of primary DNS server in case of the service interruption. But this scheme is difficult for providing DNS service constantly in case of DDoS attack, which brings about much network load or network problems in DNS server group. Therefore, This paper proposed the scheme to locally distribute load of DNS server, and the use of address system to group the distributed DNS servers. Also, it proposed the authentication scheme of the correspondent server in case the server is changed in DNS server group having grouping address. In this paper, it is shown that the prosed scheme guarantees the improved service reliability with maintaining the present service performance through the evaluation. Through this, we can expect the high improved DNS service can be provided in the Internet environment in the future.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1034-1041
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• 2011

Generally, In distributed online game server system, game maps are processed separately by means of dividing into several unit blocks. But the keeping normal distribution of user in game map is very difficult because preferences of game users are not same according to individual user's private character. For this reason, if the huge number of users concentrate on particular region of same game map at once, the game server exceed their threshold so that the system can be getting down. Conversely, the efficiency of system goes down considerably because the game server must perform map processing continuously even under user_empty situation. To solve this problem, in this paper, we propose a Map management method to control relatively normal distribution of users in game maps using Map Balance Server. In suggested model, we can reduce the load of game servers by means of turn off the game map processing temporary when a server is under user_empty situation. we also can maximize server performance by means of redistribution of map processing load among servers.

• 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.

• The Transactions of the Korea Information Processing Society
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• v.6 no.1
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• pp.57-65
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• 1999

The simulation which is larger scale, complex and interactive with clients treat a lot of messages. It can be thinking more efficient distributed simulation than sequential one. The training simulation with multi-users is geographically distributed, and required high cost to operate and maintain system as increasing user requirements. The adaptation of web technology to the simulation can be a way to solves it without cost added. But dynamic web environment can causes causality error of events. This paper is concerned with client-server model, which supports interaction between distributed simulation server and web browser, and it is implemented by Java distributed object model. the result have shown that the distributed simulation is performed correctly on dynamic environment.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.1 s.94
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• pp.161-166
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• 1999

Virtual Manufacturing System(VMS) is a computer model that represents the precise and whole structure of manufacturing systems and simulates their physical and logical behavior in operation. In this paper, a real time simulation for the virtual factory is proposed to integrate a process planning with scheduling under distributed environments. In order to communicate the information under distributed environments, we use a server/client concept using socket program and internet.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2431-2434
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• 2003

In this research, our goal is to realize Korean Distribute TTS system with server/client function in wireless network. The speech databases and some routines of TTS system is stuck with the server which has strong functions and we made Korean speech databases and accomplished research about DB which is suitable for distributed TTS. We designed a terminal has the minimum setting which operate this TTS and designed proper protocol so we will check action of Distributed TTS.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.441-443
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• 2004

With the rapid development of the Internet over the recent years, in conjunction with the transmission protocol TCP/IP and the latest version of hypertext(HTML) facilities, new opportunities have come into existence for the use of the network for the remote control of experiments and the other practical systems in engineering education. Using graphical software environments in client-server systems, remote control and monitoring system can be easily designed. Client-server systems have some general advantages when compared with simple Remote-Access Systems. In this paper we present a client-server architecture for the distributed measurement system of instrumentation over the Internet. The proposed solution allows multi-user, multi-instruments sessions to be obtained by means of a queuing process and provides instrument lock capability. Client applications can be easily developed by using conventional high-level programming languages or well-assessed virtual instrumentation frameworks.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2S
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• pp.577-593
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• 2000

A distributed video-on-demand (VoD) system is one where collection of video data is located at dispersed sites across a computer network. In a single site environment, a local video server retrieves video data from its local storage device. However, in the setting of a distributed VoD system, when a customer requests a movie from the local server, the server may need to interact with other servers located across the network. In this paper, we present three types of presentation plans that a local server must construct in order to satisfy the customer request. Informally speaking, a presentation plan is a temporally synchronized detailed sequence of steps that the local server must perform for presenting the requested movie to the customer. This involves obtaining commitments from other video servers, obtaining commitments from the network service provider, as well as making commitments of local resources, within the limitations of available bandwidth, available buffer, and customer data consumption rates. Furthermore, for evaluating the goodness of a presentation plan, we introduce two measures of optimality for presentation plans: minimizing wait time for a customer, and minimizing access bandwidth is used. We develop algorithms to compute optimal presentation plans for all three types, and carry out extensive experiments to compare their performance. We have also mathematically proved certain results for the presentation plans that had previously been verified experimentally in the literature.

• Journal of Digital Contents Society
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• v.12 no.4
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• pp.559-565
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• 2011

In this paper, I propose a distributed game server system which has flexibility of enormous game character's processing in MMORPG using block scheme. I proposed game servers in distributed system grouped with zone which charge of each map, and the game servers in this zone divide game map into several unit blocks and process distributing blocks to game servers according to its performance. I proposed distributed game server system using block scheme can add/drop game map to/from easily through block process method in game and communication servers. Therefore, my proposed system can enormous character processing and add user created game map to existed game map easily in the future as well. Also, my scheme increases the system utilization and upgrades system stability by dynamic distribution of game map according to the number of characters and performance of servers.

• Proceedings of the Korea Database Society Conference
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• 1994.09a
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• pp.49-69
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• 1994

A client/server system has become the computing architecture for the business organization which seeks competitive edges. Technically, a client/server system places application processing close to the user and thus increases performance. This paper's two primary goals are (i) to present a performance model for client/server database systems and (ii) to demonstrate analytically the effectiveness of client/server computing in comparison with other computing architectures via an illustrative example. The model is most likely to be used as a practical performance guide for client/server computing.