• Journal of KIISE:Information Networking
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• v.27 no.4
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• pp.544-551
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• 2000

본논문은 ATM망에서 다중 그룹 통신 서버를 이용하여 다양한 멀티캐스팅 응용 서비슬 지원할 수 있는 통합된 그룹 통신 플랫폼의 설계 및 구현 내용을 기술하였다. 본 논문에서 구현한 플랫폼은 단일 그룹 통신 서버에서 발생할 수 있는 트랙픽 부하로 인한 병목현상을 줄이기 위해 다중 그룹 통신서버 구조를 가지며 테스트를 위하여 멀티캐스팅 응용 서비스를 통하여 올바른 동작을 검증하였다. 이플랫폼은 하부 ATM망을 기반으로 하여 TCP/IP 프로토콜 및 Native ATM 프로토콜 상위에서 동작하여 다양한 멀티캐스팅 응용 및 서비스를 효과적으로 지원할 수 있다.

• Proceedings of the IEEK Conference
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• 2001.06c
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• pp.233-236
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• 2001

When we execute a online game in the network, a lots of game informations and user informations are transfered between game server and game clients. This information has deferent data structure and communication protocol. So, game developers will be design the communication protocols and packet structures after analyze the game. And, they will be design the database for user management. It will be lots of overload to the game developers. From a user point of view, they must be register to each game server to use several games. It is a undesible operation for the game users. This problems are solved by using the communication server which operates commonly with several game servers. Game providers can get the benefit of multiple access of users and get freedom from user management. Game users can access the several games which connected to communication server by register the communication server only. In this paper we design the communication packet and propose a communication protocol which operates on the communication server described previous.

• Proceedings of the IEEK Conference
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• 2001.06c
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• pp.101-104
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• 2001

Over the last few years, streaming audio and video content on Internet sites has increased at unprecedented rates. The predominant method of delivering video over the current Internet is video streaming such as SureStream or Intelligent Stream. Since each method provides the client with only one data stream from one server, it often suffers from poor qualify of pictures in the case of network link congestion. In this paper, we propose a novel method of delivering video stream based on wavelet to a client by utilizing multi-threaded parallel connections from the client to multiple servers and to provides a better way to address the scalability functionalities. The experimental results show that the video quality delivered by the proposed multithreaded stream could significantly be improved over the conventional single video stream methods.

• Journal of Information Processing Systems
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• v.13 no.3
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• pp.518-532
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• 2017

Due to the rapid growth of the amount of data, research on bigdata processing has been highlighted. For bigdata processing, CUBRID Shard is able to support query processing in parallel way by dividing the database into a number of CUBRID servers. However, CUBRID Shard can answer a user's query only when the query is required to gain accesses to a single CUBRID server, instead of multiple ones. To solve the problem, in this paper we propose a CUBRID based distributed parallel query processing system that can answer a user's query in parallel and distributed manner. Finally, through the performance evaluation, we show that our proposed system provides 2-3 times better performance on query processing time than the existing CUBRID Shard.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1633-1636
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• 2003

In this paper, we developed the scheme to grow to use newly added disk space without having to kill the application, unmount file system. This scheme, called online resizing, can resize the file system layout with the advent of Logical Volume Manager. The online resizing scheme is designed and implemented in linux cluster system where multiple hosts share the disk data in storage area network environment. It is incorporated with SANfs shared file system and can perform resizing technique with SANfs-VM volume manager. The experimental result shows that it can maximize the availability and capacity of the SANfs system which are important for modem servers where must not lose their customer.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1481-1484
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• 2001

Most implementations of HTTP servers do not distinguish among requests for hypermedia data from different clients. Commercialization of Web site is becoming increasingly common. Therefore providing quality of service with members paying to the site is often an important issue for the hosts. For some uses, such as web prefetching or multiple priority schemes, different levels of service are desirable. We propose server-side TCP connection management mechanisms to provide two different levels of Web service, high and regular levels by setting different timeout for inactive connection. Therefore this mechanism can effectively provide different service classes even in the absence of operating system and network support.

• Journal of applied mathematics & informatics
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• v.33 no.1_2
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• pp.77-87
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• 2015

Parallel lines are often used to increase production rate in many manufacturing systems where the main line splits into several lines in parallel, and after some operations, they merge into a main line again. Queueing networks with finite buffers have been widely used for modeling and analyzing manufacturing systems. This paper provides an approximation technique for multi-server two-stage networks with merge configuration and blocking which will be a building block for analysis of general manufacturing systems with parallel lines and merge configuration. The main idea of the method is to decompose the original system into subsystems that have two service stations with multiple servers, two buffers and external arrivals to the second stage are allowed. The subsystems are modeled by level dependent quasi-birth-and-death (LDQBD) process.

• The Journal of Society for e-Business Studies
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• v.5 no.1
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• pp.105-122
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• 2000

Enterprise integration and virtual enterprise are practical visions of industrial information implementations in the information society. In these environments, the distributed and heterogeneous data sources should be exchanged and shared in effective and integrated way. However, the distributed and heterogeneous data sources are managed by independent and heterogeneous computer systems, thus system users and developers are faced difficulties in implementing enterprise integration environments, In this study, we designed and developed a database broker system utilizing a routing broker method to provide transparent location access mechanisms for the distributed and heterogeneous data sources. The proposed mechanism is designed to act as a middle tier between clients and multiple servers, and adopts Java, CORBA, and JDBC as its state-of-the-art techniques.

• International Journal of Contents
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• v.6 no.3
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• pp.19-24
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• 2010

Task scheduling is an integrated component of computing with the emergence of grid computing. In this paper, we address two different task scheduling models, which are static Round-Robin (RR) and dynamic Fastest Site First (FSF) task scheduling method, using extended timed marked graphs, which is a special case of Stochastic Petri Nets (SPN). Stochastic reward nets (SRN) is an extension of SPN and provides compact modeling facilities for system analysis. We build hierarchical SRN models to compare two task scheduling methods. The upper level model simulates task scheduling and the lower level model implements task serving process for different sites with multiple servers. We compare these two models and analyze their performances by giving reward measures in SRN.

• Korean Management Science Review
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• v.22 no.2
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• pp.99-107
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• 2005

Recently, Tang and Chanson proposed a minimum cost distribution model for replicated Web contents subject to an expiration-based consistency management. Their model is a progress in that it can consider multiple replicas via the network of servers located on the Web. The proposed greedy heuristic, however, has an undesirable feature that the solution tends to converge a local optimum at an early stage of the algorithm. in this paper, we propose an algorithm based on a simple idea of preventing the early local convergence. The new algorithm provides solutions whose cost are, on the average, 27$\%$ lower than in the previous algorithm.