• KIISE Transactions on Computing Practices
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• v.22 no.1
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• pp.26-31
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• 2016

Migrim(Migration enhanced Grid Middleware) is a communication middleware between embedded devices and multiple servers. In traditional client-server communication, users' requests are sent to and processed by a designated server even though the server may suffer from a heavy load. In addition, the designated server may not have proper information to process the user's request correctly. Proposed connection migration mechanism and transaction migration mechanism are designed to improve the performance and accuracy of request processing. The connection migration is a procedure for delegating a connection to another server, which results in a well-distributed balancing of load among the servers. The transaction migration is a procedure for delegating a transaction to another server, and improves the accuracy of response.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.19-24
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• 2009

When a dynamic method is applied at the time of occurrence of an client's connection request for most of the online gaming server engine, the gaming server is processing a session connection, it's initialization. Yet, such a method will cause a lot of loading and bottle-neck in the gaming server at the same time. Therefore we propose the object polling scheme to minimizes a memory fragmentation and loading of the initialization on the client using a static allocation method for an efficient On-lin gaming serverin this paper. We implement the gaming server applying to our proposed scheme, and we show an improvement in our proposed scheme by performance analysis in this paper.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.12
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• pp.1198-1206
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• 2007

It is common to use PC or Digital picture frame in stand-alone fashion to view images, movies, or to listen MP3 musics which are considered as multimedia contents, However, such existing methods have weakness for expanding network requirements or augmenting extra data, in such case inevitably requiring external devices. With keeping in mind for such expansion, in this study, we have suggested a new concepts of network module which may utilize an image server for data transmission, in the proposed module, data alarm packet was defined for alerting incoming data from the image server and it became possible to synchronize between the image server and device not only in wired but also in wireless environments through UART. The method consists of a control module for an image server and a synchronization module between the server and the device. We have also tested the feasibility for future commercial usages such as advertisements through performance evaluations.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.207-215
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• 2012

This paper proposes a proxy-based caching optimization scheme for improving the streaming media services in wireless mobile ad hoc networks. The proposed scheme utilizes the proxy for data packet transmission between media server and nodes in WLANs, and the proxy locates near the wireless access pointer. For caching optimization, this paper proposes NFCO (non-full cache optimization) and CFO (cache full optimization) scheme. When performs the streaming in the proxy, the NFCO and CFO is to optimize the caching performance. This paper compared the performance for optimization between the proposed scheme and the server-based scheme and rate-distortion scheme. Simulation results show that the proposed scheme has better performance than the existing server-only scheme and rate distortion scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.359-362
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• 2014

With recent growing of application service, servers are required to sustain great amount of data and to handle them quickly: besides, data must be processed securely. The main security algorithm used in security services of server is AES(Advanced Encryption Standard - 2001 published by NIST), which is widely accepted in the world market for superiority of performance. In Korea, NSRI(National Security Research Institute) has developed ARIA(Academy, Research Institute, Agency) algorithm in 2004 and LEA(Lightweight Encryption Algorithm) algorithm in 2012. In this paper, we show advantage of LEA by comparing performance with AES and ARIA in various servers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1096-1103
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• 2000

The default server strategy is commonly used for location and state managements of mobile host in mobile computing. With this strategy, we can find the cell of destination mobile host to send data by querying the default server. In SDN(single Default Notification) strategy which is a kind of default server strategy, the call is established after the location and state of the callee is acquired to the query server by querying the default server. But the communication cost overhead from the default server is increased if there are large number of cells and query requests, and if it is too far from the default server to a base station. Still more it will be unable to establish any calls to a mobile host when there is a fault in the default server of this host. In this paper, we suggest add evaluate a default server replication strategy to reduce the communication cost overhead and to make the service available.

• 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 KIISE:Databases
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• v.36 no.5
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• pp.399-404
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• 2009

In a multiple-server DBMS using the share-disk model, when a server process updates data, the updated ones are not immediately reflected to the buffers of the other server processes. Thus, the other server processes may read invalid data. In this paper, we propose a novel method to solve this problem. In this method the server process stores the identifiers and timestamps of the pages that have been updated during a transaction into the coherency volume when the transaction commits. Then, the server process invalidates its buffers of the pages updated by the other server processes by accessing the coherency volume when the lock is acquired, and, subsequently, read the up-to-date versions of the pages from disk. This method needs only a very small coherency volume and shows a good performance because the amount of data that need to be accessed is very small.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.10
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• pp.1866-1874
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• 2008

Existing web server lowers the whole capacity of system because of the problem on the processing load of server by closing connection increasing code handshake operation, and remarkable decrease of server capacity if it is the state of overload. Also, there occurs disadvantages of increasing connection tine about client's request and response time because handling of client's multi-requests is not smooth because of thread block and it requests a lot of time and resources for revitalization of thread. Therefore, this paper proposes the extended web server which provides the technique for delay handling and improves the overload of server for better system capacity, communication support, and the unification which is the advantage of web service. And it evaluates the existing system(implemented at Tomcat 5.5) and the proposed mobile web server architecture. The extended server architecture provides excellent exchange condition for system capacity and evaluates improved web server architecture which combines multi-thread with thread pool. The proposed web service architecture in this paper got the better result of improved capacity benefit than the evaluation result of original Tomcat 5.5.