• Journal of Korea Multimedia Society
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• v.7 no.10
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• pp.1400-1411
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• 2004

Recently, explosion of internet user requires fundamental changes on the architecture of Web service system, from single server system to clustered server system, in parallel with the effort for improving the scalability of the single internet server system. But current cluster-based server systems are dedicated to the single application, for example, One-IP server system. One-IP server system has a clustered computing node with the same function and tries to distribute each request based on the If to the clustered node evenly. In this paper, we implemented the more useful application service platform. It works on shared clustered server(back-end server) with an application server(front-end server) for a particular service. An application server provides a particular service at a low load by itself, but as the load increases, it reconfigures itself with one or more available server from the shared cluster and distributes the load on selected server evenly We used PVM for an effective management of the clustered server. We found the implemented application service platform provides more stable and scalable operation characteristics and has remarkable performance improvement on the dynamic load changes.

• Convergence Security Journal
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• v.7 no.3
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• pp.1-6
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• 2007

It is important to manage and correctly evaluate the performance of server in order to improve he performance of server. That is, with the aim of finding whether resources are properly utilized, it is a method to improve both software and hardware aspects. Conventional method in evaluating the server performance involved installing software between server and client and generating the load and by simulating the process, it evaluated the handing efficiency of work load generated per packet volume. Therefore, this paper aims to pro-vide precise measurement method by distinguishing the characteristics of web server and the users' usage pattern and by evaluating the work load management through applying various standards. Specially, it presents the evaluation method from web service of personal and business.

• Journal of the Korea Society of Computer and Information
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• v.15 no.6
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• pp.57-64
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• 2010

Due to the limited storage space in video proxy server, it is often required to replace the old video data which is not serviced for long time with the newly requested video. This replacement causes the service delay and increase of network traffic. To circumvent this problem, we propose the an efficient replacement scheme in a video proxy server. In addition, we present a video data management technique for decreasing the number of replacement in video proxy server. For this purpose, we employ a memory in video proxy server. If the video segment which is loaded in memory is requested once again by a different user, this segment is resided in memory. The video in the memory is stored in the video proxy server depending on the consuming pattern by users. The simulation results show that the proposed algorithm performs better than other algorithms in terms of packet hit rate and number of packet replacement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.619-622
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• 2005

When Digital Contents goes through production${\cdot}$delivery${\cdot}$consumption, MPEG(Moving Picture Expers Group)-21 IPMP(Intellectual Property Management and Protection) defines standard which have defined by FCD(Final Committee Draft) level to keep the Digital Contents in safety. And development of system which applied to latest standard to protect and manage the broadcasting contents is required. Currently, the system to protect and manage the broadcast contents consists of fourth organizations which means production server, tool server, license server, consumption server. In this paper, we made production server to parse REL(Right Expression Language) document that has right information for content from license server, and create metadata based on MPEG-21 IPMP about the content that applied to watermark. then, after it do remuxing, transmit the protected data to consumption server.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.3
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• pp.29-38
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• 1998

This ppaer suggests a congestion control scheme for CL(ConnectionLess) overlay network using the feedback loops getween CL werver, between CL servers, and the header translation table of CL server. The CL overlay network for CBDS(Connectionless Broadband Data Service) defined by ITU0T(International Telecommunication Union-Telecommunication) consists of CL servers which route frames and links which connect between CL user and CL server or between CL servers. In this CL overlay network, two kinds of congestions, link congestion and CL server congestion, may occur. We suggest a scheme that can solve the congestion using ABR(Available Bit Rate) feedback control loop, the traffic control mechanism. This scheme is the link-by-link method suing the ABR feedback control loops between CL user and CL server or between CL servers, and the header translation table of CL server. As CL servers are always endpoints of ABR connections, the congestion staturs of the CL server can be informed to the traffic sources using RM(Resource Management) cell of the ABR feedback loops. Also CL server knows the trafffic sources making congestion by inspecting the source address field of CLNAP-PDUs(ConnectionLess Network Access Protocol - Protocol Data Units). Therefore this scheme can be implemeted easily using only both ABR feedback control loop of ATM layer and the congestion state table using the header translation table of CL server because it does not require separate feedback links for congestion control of CL servers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.545-551
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• 2001

Current Internet system of the entrance exam information to the university that is depending on searching key to solve the overloaded p개blem in the network and DB server or other tools to support HTML edit, haven't satisfied user's wants by supplying uniformed searching system. So this thesis will establish EEIS(Entrance Examination Information System) to prevent database overload phenomena when many users request a great amount of data at the same time and improve the decrease of speed and overload problem in DB server. EEIS play a role of bridge between outside client and DB server by placing VVS(Virtual View Server) between web server and DB server. By that method this system give users several usefulness in convenience and variety by supplying realtime data searching function to user EEIS also give inner system manager more efficiency and speed in control the management system by solving those problem. This system is design and implementation to satisfy user's desire and give them more convenience and bring up the confidence of university that adopt this system at the end.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.123-128
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• 2019

In modern society, there are WEB sites that provides information in various fields by many advances in IT technology. As the number of users accessing the Web increases, one server becomes unavailable, and multiple servers are deployed to provide the service. In addition, systems that control servers are required to manage multiple servers. However, server control systems in the existing market are mostly those that notify managers through SMS and apps when a server's down or a controlled port is closed. However, in case of servers that generate a lot of traffic, the Web server and the WAS are operated and managed each independently. The WEB and WAS provide service by connecting to each other. However, the connection between WEB and WAS may be disconnected due to various environmental factors. In this case, the existing control system can not determine whether the service is working properly. Even in the case of WEB and WAS of a server that is operated independently, there is a phenomenon that the existing control system does not know the problem even when the normal service is not provided due to environmental factors such as disconnection to DB. In this paper, we implemented a system to check the normal state of Web service using Web crawling to solve this problem.

• 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.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.353-360
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• 2017

The Internet of Things(IoT) security has more need than a technical problem as it needs series of regulations and faultless security system for common purposes. So, this study proposes an efficient key management in order that can be trusted IoT data in cloud computing. In contrast with a key distribution center of existing sensor networks, the proposed a federation key management of cloud proxy key server is not central point of administration and enables an active key recovery and update. The proposed key management is not a method of predetermined secret keys but sharing key information of a cloud proxy key server in autonomous cloud, which can reduce key generation and space complexity. In addition, In contrast with previous IoT key researches, a federation key of cloud proxy key server provides an extraction ability from meaningful information while moving data.

• Journal of the Korean Operations Research and Management Science Society
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• v.19 no.3
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• pp.235-241
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• 1994

We consider a B/G/1 queueing with vacations, where the server closes the gate when it begins a vacation. In this system, customers arrive according to a Bernoulli process. The service time and the vacation time follow discrete distributions. We obtain the distribution of the number of customers at a random point in time, and in turn, the distribution of the residence time (queueing time + service time) for a customer. It is observed that solutions for our discret time B/G/1 gated vacation model are analogous to those for the continuous time M/G/1 gated vacation model.