• Journal of Korean Institute of Industrial Engineers
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• v.28 no.3
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• pp.319-330
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• 2002

We consider BMAP/G/1 queueing system with N-policy and multiple vacations. We derive the vector generating functions of the queue length in a factorized form and interpret the factorization. We also derive the mean queue length.

• Journal of the Korean Operations Research and Management Science Society
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• v.21 no.1
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• pp.31-50
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• 1996

In this paper we prescribe a replication server scheme with an algorithm DRF (Differential Refresh File) to refresh multiple materialized views and replicas in distributed environments. Before sending relevant tuples in server sites to client sites, an effective tuple reduction scheme is developed as a preprocessor to reduce the transmission cost. Because it utilizes differential files with out touching base relations, the DRF scheme can help to minimize the number of locks, which enhances the system's performance.

• ETRI Journal
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• v.35 no.6
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• pp.960-968
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• 2013

To implement a cloud game service platform supporting multiple users and devices based on real-time streaming, there are many technical needs, including game screen and sound capturing, audio/video encoding in real time created by a high-performance server-generated game screen, and real-time streaming to client devices, such as low-cost PCs, smart devices, and set-top boxes. We therefore present a game service platform for the running and management of the game screen, as well as running the sound on the server, in which the captured and encoded game screen and sound separately provide client devices through real-time streaming. The proposed platform offers Web-based services that allow game play on smaller end devices without requiring the games to be installed locally.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.635-638
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• 2002

In this paper, the connection device of RS232C and TCP/IP implementation using ARM processor and LINUX is proposed. Data interaction flash memory the multiple serial ports are transferred to ARM processor and the data are processed and formed into data packet for transfer via internet protocol. Packet flash memory Internet is decoded to extract the serial port data. The serial ports supports RS232C asynchronous protocol communication and control program is developed in GNU-C and installed in the on-board memory for packet conversion and control. The research result can be applied to terminal server, printer server and multiple serial ports equipments.

• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.4
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• pp.157-170
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• 1999

The web-based groupware systems hold many possibilities for system developers and users. Especially, web-based group collaborative systems are emerging as enterprise-wide information systems. Since data in group collaborative systems are apt to be shared among multiple concurrent users and modified simutaneously by them, the web-based group collaborative systems must support synchronous collaboration in order to provide users with synchronized and consistent views of shared data. However, current web technologies have limitations in supporting this, largely because the existing Hypertext Transfer Protocol(HTTP) is unidirectional and does not allow web servers to send messages to their web browsers without first receiving requests from them. This paper proposes an active web server that can overcome such limitations and facilitate synchronous collaboration in web-based group collaborative systems. To accomplish such goals, the active web server manages dependency relationships beween shared data and web browsers referencing them and actively propagates changing details of the shared data to all web browsers referencing them. And, this paper examines usefulness and effectiveness of the active web server to apply it to the ball-bearing design example of concurrent engineering design systems. The prototype system of the active web server is developed on a commercial Object-oriented Database Management System(0DBMS) called OBJECTSTERE using the C++ programming language.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.304-311
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• 2005

OCSP has specific characters which can suspend, close, and correct in real time. But, as more clients use the OCSP server verification, more updated information is needed, which can lead to jamming in the OCSP server. To apply this technique of Distributed OCSP server so as to reduce the certificate verification OCSP from jamming. Also, the Distributed OCSP server will solve the problems of the intensive central structure. Simulation results show that the average reply time of certificate verification request and server load are reduced in the case using distributed OCSP. In addition to this advantage, resource distribution and fault tolerance are acquired because of multiple OCSP.

• ETRI Journal
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• v.41 no.5
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• pp.670-683
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• 2019

In this paper, we analyzed the signal integrity of a system interconnection module for a proposed high-density server. The proposed server integrates several components into a chassis. Therefore, the proposed server can access multiple computing resources. To support the system interconnection, among the highly integrated computing resources, the interconnection module, which is based on Serial RapidIO, has been newly adopted and supports a bandwidth of 800 Gbps while routing 160 differential signal traces. The module was designed for two different stack-up types on a printed circuit board. Each module was designed into 12- (version 1) and 14-layer (version 2) versions with thicknesses of 1.5T and 1.8T, respectively. Version 1 has a structure with two consecutive high-speed signal-layers in the middle of two power planes, whereas Version 2 has a single high-speed signal placed only in the space between two power planes. To analyze the signal integrity of the module, we probed the S-parameters, eye-diagrams, and crosstalk voltages. The results show that the high-speed signal integrity of Version 2 has a better quality than Version 1, even if the signal trace length is increased.

• Journal of the Korean Society of Systems Engineering
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• v.15 no.2
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• pp.66-71
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• 2019

In digital pathology, an electronic system in the biomedical domain storage of the files is a big constrain and because all the analysis and annotation takes place at every user-end manually, it becomes even harder to manage the data that is being shared inside an enterprise. Therefore, we need such a storage system which is not only big enough to store all the data but also manage it and making communication of that data much easier without losing its true from. A virtual server setup is one of those techniques which can solve this issue. We set a main server which is the main storage for all the virtual machines(that are being used at user-end) and that main server is controlled through a hypervisor so that if we want to make changes in storage overall or the main server in itself, it could be reached remotely from anywhere by just using the server's IP address. The server in our case includes XML-RPC based API which are transmitted between computers using HTTP protocol. JAVA API connects to HTTP/HTTPS protocol through JAVA Runtime Environment and exists on top of other SDK web services for the productivity boost of the running application. To manage the server easily, we use Tkinter library to develop the GUI and pmw magawidgets library which is also utilized through Tkinter. For managing, monitoring and performing operations on virtual machines, we use Python binding to XML-RPC based API. After all these settings, we approach to make the system user friendly by making GUI of the main server. Using that GUI, user can perform administrative functions like restart, suspend or resume a virtual machine. They can also logon to the slave host of the pool in case of emergency and if needed, they can also filter virtual machine by the host. Network monitoring can be performed on multiple virtual machines at same time in order to detect any loss of network connectivity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.833-838
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• 2014

Recently the use router is to allow multiple computers by one IP can be connect to the Internet. Also, the PC or server in order to use a Web server or a print server, Web Hard, P2P should be settings. In this paper, we are building a multi-functional Web server that using a router supported OpenWRT based on network settings and firewall settings and a variety of services. A web server can be provided the Internet phone and secure multimedia service Web server router based OpenWRT may be provided through a mobile app and the PC application service.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.647-653
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• 2011

In vessels, various communication systems are now working with different vendor-specific ways, which are apt to cause the inter-operability problems. That, of course, leads to needs of standardization of communication network systems for vessels. The e-navigation system introduced by IMO also takes the standardization process as expected. In this paper, a 4S multiple media communication switching server for seamless communications among existing media for vessels is introduced, and the development of a information exchange software for the sever and its functionality verification results are presented as well.