• The KIPS Transactions:PartA
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• v.14A no.7
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• pp.443-450
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• 2007

Performance scalability and storage scalability become important in a large scale cluster of wireless internet proxy cache servers. Performance scalability means that the whole performance of the cluster increases linearly according as servers are added. Storage scalability means that the total size of cache storage in the cluster is constant, regardless of the number of cache servers used, if the whole cache data are partitioned and each partition is stored in each server, respectively. The Round-Robin based load balancing method generally used in a large scale server cluster shows the performance scalability but no storage scalability because all the requested URL data need to be stored in each server. The hashing based load balancing method shows storage scalability because all the requested URL data are partitioned and each partition is stored in each server, respectively. but, it shows no performance scalability in case of uneven pattern of client requests or Hot-Spot. In this paper, we propose a novel dynamic hashing method with performance and storage scalability. In a time interval, the proposed scheme keeps to find some of requested URLs allocated to overloaded servers and dynamically reallocate them to other less-loaded servers. We performed experiments using 16 PCs and experimental results show that the proposed method has the performance and storage scalability as different from the existing hashing method.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.6
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• pp.318-330
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• 2002

This paper discusses the design and implementation of a video server which uses tertiary device, such as magneto-optical jukebox or tape library, as a source of media archiving. In order to handle the tertiary device in the framework of disk-based stream service model, a sophisticated streaming model is required for server and it should consider the device-specific performance characteristics of tertiary storage. We have carefully designed the streaming mechanism for server whose key functionalities include stream scheduling, disk caching and admission control. The proposed system has been implemented on Windows 2000 platform which is equipped with a magneto-optical jukebox. The design principles of the server are validated with the experiments and the performance characteristics is analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2169-2175
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• 2014

In this paper we have proposed a new distributed architecture of session-based instant message system, in which multiple servers can distribute loads effectively to improve system extendability. The server of session-based instant message system should manage SIP sessions to transfer instant message with multimedia data to each users, and it should process large amount of presence informations from each users. Therefore load of the server should be distributed as the number of users increases. In our system, when server load increases according to large user numbers, the load are distributed by selecting a server with the lowest load value, or new server is created to allocate the message processing. Therefore the overall load of instant message system can be dynamically distributed. A new presence information data format with added elements for controlling server load has been designed for this purpose, and SIP messages exchanging procedure between servers and users has been also suggested. The performance of our proposed system has been analysed by simulation, and showed improvement of performance.

• Journal of KIISE:Databases
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• v.31 no.5
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• pp.457-467
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• 2004

The efficiency of algorithms managing data caches has a major impact on the performance of systems that utilize client-side data caching. In these systems, two versions of data can be maintained without an additional space overhead of the server by exploiting the replication of data in the server's buffer and clients' caches. In this paper, we present a new cache consistency algorithm employing versions: Two Versions-Callback Locking (2V-CBL). Our experimental results indicate that 2V-CBL provides good performance, particularly outperforms a leading cache consistency algorithm, Asynchronous Avoidance-based Gache Consistency, when some clients run only read-only transactions.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1035-1038
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• 2005

This paper describes the designs and the implementations of two H/W IPSec Systems, look-aside and inline, on TOE (Transport Offloading Engine). These systems aim for guaranteeing the security of datagram networks while preserving the bandwidth of gigabit networks. The TOE offloads a host CPU from network burdens, so that it makes the gigabit wire speed possible, and then deeper level security architecture of the IPSec guarantees the security of gigabit service network dominated by datagram packets. The focus of this paper is to minimize the TOE's performance degradation caused by the computation-oriented IPSec. The look-aside IPSec system provides a significant improvement in the CPU offload of the IPSec cryptography loads. However, the inline system completely offloads the host CPU from whole IPSec loads, providing significant additional cost saving compared to the look-aside system. In this paper, the implementations of TOE cards including commercial IPSec processors are presented. As the result of performance evaluation with the protocol analyzer, we can get the fact that the inline IPSec system is 8 times faster than the S/W system and 2 times faster than the look-aside system.

• The KIPS Transactions:PartB
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• v.9B no.6
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• pp.863-868
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• 2002

In this paper we suggested a map management method for on line RPG supporting full 3D. In general, it is possible to support full 3D with client engine. Rut the online game server cannot show the expected performance under normal price constrains with current hardware technology, since the amount of data for management of 3D on-line game server increase exponentially with respect to the size of game world. To solve this problem. we introduced the "special object" which makes it possible for on-line game server with low performance hardware. This suggested method gave concrete from to manage full 3D for server as well as clients.s clients.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.385-391
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• 2004

Today, mobile technology is developing very fast and people use internet through mobile phones. Using mobile phones, people use games, email, avatar and other services. We designed client/server modules in order to join email and avatar together. First two major server modules were designed, one of them is DB management module for avatar user information and the other is email management module. One the client side, we designed avatar image animation module and a module for showing the email contents. The purpose of the design is to reduce the performance overhead on the client side as mobile phones cannot be used as a high performance device. We propose and implement a new avatar based service using the SK-VM environment, that is different from the current avatar services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.816-818
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• 2017

In this paper, we perform a performance analysis of a surveillance camera network system with an image recognition server based on frame discard rate and server utilization. Surveillance camera states are divided into recognition states and silence states to analyze the various parameters such as the optimum number of image frames and the optimum number of cameras based on the processing capacity of the server. The analyzed results will be useful for efficient operation of the evolving surveillance camera network systems.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.22-29
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• 2022

Recently, with the development of mobile computing power, mobile-based VR and AR services are being developed. Due to network performance and computing power constraints, VR and AR services using large-capacity 3D content have limitations. A study on an efficient 3D content load method for a mobile device is required. The conventional method downloads all 3D content used for AR services at the same time. In this paper, we propose an active 3D content load according to the user's track. The proposed method is a partitioned 3D object load. Edge servers were installed for each area and connected through the MESH network. Partitioned load the required 3D object in the area referring to the user's location. The location is identified through the edge server information of the connected AP. The performance of the proposed method and the conventional method was compared. As a result of the comparison, the proposed method showed a stable Mobile AR Service. The results of this study, it is expected to contribute to the activation of edge server-based AR mobile services.

• The Transactions of the Korea Information Processing Society
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• v.5 no.1
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• pp.161-171
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• 1998

In this paper, we shows the implementation of Web based performance manager which analyze the traffic of a Web server to support the diagnostics of it. The manager monitors the HTIP traffic by polling and measures and presents is performance on demand. To enhance the adaptability of management interface Web based interfaces with JAVA is used. Recently, the need of traffic management on s Web has grown, because of increasing Web traffic. Therefore, the traffic management of Web service and the effective management of a Web server's performance are needed. We have designed interfaces with which is comprised of Collection-Request, Analysis-Request, Realtime-Monitoring, Comparison-Analysis on a client with Web Browser on a network, and implemented the server system that can analyze these requests. Also we have introduced some perfonnance indicator by referring a Web related MIB. Also, we have designed and developed a message format for communication between the Web client and the server system.