• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.171-174
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• 2005

According as marine leisure industry has developed and the demand of leisure culture has increased rapidly, a desire about service which supply marine safety and connect marine information is enlarging. The performance of personal mobile device has improved and been evolved by composition terminal. So, it became possible that storage and expression of multimedia information as well as simple communication facility. Domestic wireless internet has given development strain to developer and contents Provider(CP) because of different platform. And this has become hindrance factor of wireless internet activation. But, recently, the use of WIPI(Wireless Internet Platform for Interoperability), the wireless internet standard platform, could use different wireless application programs and also guarantee the independency for hardware. We wish to develop contents of download form that supply geographic information of Electronic Navigational Chart(ENC) in the marine that is digitalized to carrying along terminal of WIPI base and various informations for marine leisure. For this, DB that offer ENC and additional information should be constructed. Also, we need server (CPS; Contents provider Server) that offer required contents. In this paper, we design web retrieval agent which store request information to database. When consumer required necessary information through personal mobile device, CPS can inform that by real time. So, we wish to develop agent component that parse informations in various World Wide Webs, and store to database.

• The Transactions of the Korea Information Processing Society
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• v.6 no.9
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• pp.2524-2532
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• 1999

In this paper, we present a new buffer pool management scheme designed for video type news objects to build a cost-effective News On Demand storage server for serving users requests beyond the limitation of disk bandwidth. In a News On Demand Server where many of users request for video type news objects have to be serviced keeping their playback deadline, the maximum numbers of concurrent users are limited by the maximum disk bandwidth the server provides. With our proposed buffer cache management scheme, a requested data is checked to see whether or not it is worthy of caching by checking its average arrival interval and current disk traffic density. Subsequently, only granted news objects are permitted to get into the buffer pool, where buffer allocation is made not on the block basis but on the object basis. We evaluated the performance of our proposed caching algorithm through simulation. As a result of the simulation, we show that by using this caching scheme to support users requests for real time news data, compared with serving those requests only by disks, 30% of extra requests are served without additional cost increase.

• Journal of the Korea Society of Computer and Information
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• v.18 no.11
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• pp.99-106
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• 2013

In Instant message service, the server should process instant messages and request messages which include many presence resources for users. And it also precesses massive notification messages generating from the subscribed presence resources. In this paper a new architecture of instant message service with multiple servers which can distribute loads efficiently as the number of users increases has been suggested. It also provides various functions to users using extended call processing language. The user subscribes presence information and call processing language script which describes user's functions. The server processes instant messages, presence services and call processing language scripts. New extended presence information data structure has been suggested and new call processing language operation tags have been added. Therefore extendability of the system can be increased and various services which combine presence service and call processing can be provided in this system. Furthermore instant message processing module has been integrated in the server to decrease the amount of SIP(Session Initiation Protocol) messages, and it also improves system efficiency, The performance of our proposed system has been analysed by experiments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.73-82
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• 2019

In order to build a smart factory, building a CPPS (Cyber Physical Product System) is an important system that must be accompanied. Through the CPPS, it is the reality of smart factories to move physical factories to a digital-based cyber world and to intelligently and autonomously monitor and control them. But The existing CPPS architectures present only an abstract modeling architecture, and the research that applied the OPC UA Framework (Open Platform Communication Unified Architecture), an international standard for data exchange in the smart factory, as the basic system of CPPS It was insufficient. Therefore, it is possible to implement CPPS that can include both cloud and IoT by collecting field data distributed by CPPS architecture applicable to actual factories and concentrating data processing in a centralized In this study, we implemented CPPS architecture through central OPC UA Server based on OPC UA conforming to central processing OPC UA Framework, and how CPPS logical process and data processing process are automatically generated through OPC UA modeling processing We have proposed the CPPS architecture including the model factory and implemented the model factory to study its performance and usability.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.389-405
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• 2007

In this paper, we study a k-out-of-n system with single server who provides service to external customers also. The system consists of two parts:(i) a main queue consisting of customers (failed components of the k-out-of-n system) and (ii) a pool (of finite capacity M) of external customers together with an orbit for external customers who find the pool full. An external customer who finds the pool full on arrival, joins the orbit with probability ${\gamma}$ and with probability $1-{\gamma}$ leaves the system forever. An orbital customer, who finds the pool full, at an epoch of repeated attempt, returns to orbit with probability ${\delta}\;(<\;1)$ and with probability $1-{\delta}$ leaves the system forever. We compute the steady state system size probability. Several performance measures are computed, numerical illustrations are provided.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.2
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• pp.91-95
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• 2007

Main goal of web recommendation system is to study how user behavior on a website can be predicted by analyzing web log data which contain the visited web pages. Many researches of the web recommendation system have been studied. To construct web recommendation system, web mining is needed. Especially, web usage analysis of web mining is a tool for recommendation model. In this paper, we propose web recommendation system using grid based support vector machines for improvement of web recommendation system. To verify the performance of our system, we make experiments using the data set from our web server.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1722-1728
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• 2011

The security issue in urban transit system has been widely considered as the common matters after the fire accident at Daegu subway station. The safe urban transit system is highly demanded because of the vast number of daily passengers, and it is one of the most challenging projects. We introduced a test model for integrated security system for urban transit system and built it at a subway station to demonstrate its performance. This system consists of cameras, sensor network and central monitoring software. We described the smart camera functionality in more detail. The proposed smart camera includes the moving objects recognition module, video analytics, video encoder and server module that transmits video and audio information.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.3
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• pp.189-194
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• 2002

This paper presents a state observer design for a class of MTMO nonlinear systems that has a block triangular structure. For this, the extension of the existing design for SISO triangular systems to MIMO cases is provided. Since the gain of the proposed observer. depends on a nonlinear part as well as a linear one of a system, it improves the transient performance of the high gain ob-server. Also, by using a generalized similarity transformation for the error dynamics, it is shown that order some boundedness condi-tion, the proposed observer guarantees the global exponential convergence of the estimation error. Finally, we will give a simulation example to show the validity of our design methodology.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1675-1678
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• 2004

In this paper, web based monitoring systems are implemented for multi-axis force control systems of an intelligence robot. A brief review about the principle of multi-axis force sensors and a method that can reduce the effect of noise signal to sensor performance is presented. A web based monitoring system is implemented by porting Linux at embedded systems which include Xscale processors. A device driver is developed to receive data from multi-axis force sensors in Linux operation systems. To control this device driver, a socket program for web browser is also developed. The experiments are performed to investigate the effectiveness of proposed methods. The experimental results show that the values of force sensors can be monitored by remote PCs.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.975-978
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• 2005

Vertical handoff is the process of maintaining a mobile user's active connections in the heterogeneous network. In vertical handoff, many frames can be lost since the connection between a server and a client is broken off during handoff latency. To solve this problem, in this paper, we propose an effective video streaming method for video on demand (VOD) services that provides seamless playout at the client in vertical handoff. Performance evaluations are presented to demonstrate the effectiveness of the proposed method.