• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.7
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• pp.519-525
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• 2013

The traffic classification is a preliminary and essential step for stable network service provision and efficient network resource management. However, the payload signature-based method has a significant drawback in high-speed network environment that the processing speed is much slower than other method such as header-based and statistical methods. In this paper, We propose the server IP, Port cache-based traffic classification method using application traffic locality to improve the processing speed of traffic classification. The suggested method achieved about 10 folds improvement in processing speed and 10% improvement in completeness over the payload-based classification system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.809-813
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• 2004

In this paper, we developed a network camera for CMOS camera module inspection. The design, implementation details including embedded linux porting and CPLD logics, and performance of network camera are described. The network camera consists of SoC(S3C4530A), CPLD and CMOS image sensor. In order to image data of CMOS image sensor we designed capture logics on CPLD by using VHDL program. Embedded Linux such as uClinux is performed on the network camera to utilize development environment and TCP/IP protocol specification. The application is based on socket communication between GUI on PC and Embedded Linux based network camera. When JPEG compression is applied, the transmission speed was improved enough for this system to be used for an alternative of expensive CCTV or remote monitoring system in a power plant and uninhabited places.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.283-284
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• 2008

A cross-layer optimization is becoming a popular design methodology for the IP based next generation wireless network. We begin by investigating a cross-layer optimization scheme to enhance the system performance in wireless networks. By applying cross-layer optimization methodology to WiBro distributed network, the WiBro systems are expected to gain significant performance improvement and resource utilization enhanced. For further study we highlight some open challenges and new opportunities for cross-layer design.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7A
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• pp.659-665
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• 2006

When using the Mobile IP which is the representative technology to secure the mobility in general IP networks, the packet loss during the handover is inescapable. To remedy the packet loss problem, the smooth handover was introduced. However, the smooth handover causes the packets sequence disruption during the packet forwarding procedure and it may result in the degradation of the network performance. The same problem also occurs in the WiBro (High-speed Portable Internet) system that is the next generation portable IP service system. The WiBro system, which provides the high speed data service just like xDSL and leased line in wired internet, aims to guarantee the portability, mobility, and the differentiated service based on IEEE 802.16. So, the handover mechanisms that solve the problems of packet loss and packet sequence distribution are required in the WiBro system. In this paper, we propose the handover mechanism and the packet sequence control algorithm that provide the reliability and the differentiated service for the unicast service in the WiBro system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.360-363
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• 2010

Streaming Technology can support the real-time playback without downloading and storing multimedia data in local HDD. So, client browser or plug-in can represent multimedia data before the end of file transmission using streaming technology. Recently, the demand for efficient real-time playback and transmission of large amounts of multimedia data is growing rapidly. But most users' connections over network are not fast and stable enough to download large chunks of multimedia data. In this paper, we propose an intelligent IP streaming system based on personalized media service. The proposed IP streaming system enables users to get an intelligent recommendation of multimedia contents based on the user preference information stored on the streaming server or the home media server. The supposed intelligent IP streaming system consists of Server Metadata Agent, Pumping Server, Contents Storage Server, Client Metadata Agent and Streaming Player. And in order to implement the personalized media service, the user information, user preference information and client device information are managed under database concept. Moreover, users are assured of seamless access of streamed content event if they switch to another client device by implementing streaming system based on user identification and device information. We evaluate our approach with manufacturing home server system and simulation results.

• Publications of The Korean Astronomical Society
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• v.20 no.1 s.24
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• pp.125-134
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• 2005

In this paper, we propose a small-scale Gigabit VLBI observing system for the Korean VLBI Network (KVN) under construction. The system consists of high-speed sampler, IP-VLBI board, PC-VSI board, and software correlator. Radio signal received by receiver is sampled by high-speed sample. at 1 Gsps (Gigabit sample per second) rate with 2 bits quantization. The digitized signal is recorded in PC and the software correlator does the cross correlation. IP-VLBI board will be used for the geodesy VLBI observation, while PC-VSI board is for the astronomical VLBI observation. The PC-VSI board adopts the VSI-H (VLBI Standard Interface Hardware). The proposed system is based on commercial PCs and therefore can be built inexpensively.

• The Journal of the Korea Contents Association
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• v.4 no.2
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• pp.43-49
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• 2004

SIP Caller Preference is an useful function that allows a caller to express preferences about request handling in servers. It can also feat appropriate call processing according to the callee capabilities. However, only the category of the media is considered as a criteria for target selection in the caller preference. In this case, if the callee's media information such as codec is different from the caller, an additional re­negotiation occurs for SIP call setup. Therefore, in this paper, we have suggested an extended caller preference to solve this problem. In our SIP based VoIP system, a network sewer uses detailed media informations for media stream in the session to select the target for SIP call setup. The sewer gives higher priority to the candidate which do not require re-negotiation for call setup, so that an effective call setup can be achieved in our system.

• Journal of Korea Multimedia Society
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• v.7 no.5
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• pp.680-688
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• 2004

In this paper, we propose a new handoff scheme which is efficient in hybrid mobile data network consists of cellular mobile network and wireless LAN. In this scheme, handoff is delayed until connections with wireless LAN and data rates are smoothly decreased according to becon signal strength of wireless LAN. By doing so, data transfer capacity is increased and required data buffer in handoff for mobile and network system can be decreased. We analyze new handoff scheme by computer simulation. The results show that 180Mbytes data can be transferred additionally in handoff processing and required buffer size can be decreased 1/2 with the conditions that mobile speed is 1Km/hr and the data rate of a original call is 2,048Kbps.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1B
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• pp.125-132
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• 2004

In this paper, we propose an advanced QoS provisioning scheme (AQPS) that can provide satisfied QoS for multimedia applicatios based on accurate traffic measurements. We first consider the 1xEV-DV system as a target system, extract QoS requirements or the system, and then develop a corresponding QoS provisioning method using CDMA traffic measurement. The AQPS has been verified to outperform the existing system used in the current 1xEV-DV network and to efficiently manage network resources by computer simulations.

• Journal of the Korea Computer Industry Society
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• v.2 no.4
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• pp.417-424
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• 2001

Internet networks consisting of existing routers show the limits in efficiency of traffic managements. In order to overcome the limits, MPLS System is high speed switching technology and is not based on IP address but based on label was designed. However MPLS system being based on ATM has the difficulties of supporting Qos(Quality of Service). This paper suggested the way to consist a service-assured-network using CR-LDP protocol which was designed for guaranteeing QoS in MPLS system being based on ATM switch and using qGSMP protocol, and the way to implicitly establish LSP by implementing QoS Translation and QoS Mapping in LER System.