• Proceedings of the KSR Conference
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• 2008.11b
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• pp.2058-2064
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• 2008

This study is concerned with the quantitative Quality of Service(QoS) of the Light Railway Transit(LRT) System. Generally, the QoS offered to passengers by the Operator of LRT system can be quantified in various ways. In this paper, we assumed that the QoS is a combination of both Train Delivery and Train Punctuality under considering LRT characteristics including core sub-systems such as, rolling stock, signalling, power-supply and PSD(platform screen door), etc. We also, provide a quantitative analysis method to evaluate the QoS related the reliability of LRT system.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2533-2543
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• 1997

It is necessary to understand and apply the concept of Quality of Service(QoS) for the objective selection among the computer network equipment. Because ITU-T E.800 recommendation covers the service quality of provider's viewpoint and the satisfaction of user, it can be used to evaluate and select the product of computer network systems. This paper is concerned with the development of an evaluation model using QoS and software tool for selection of the most suitable LAN switch. We apply the Analytic Hierarchy Process(AHP) method of Saaty which has been in a multiple criteria framework for an effective group decision process to the selection of LAN switch. The sample data are collected and processed from a questionnaire of professionals in the network field. And we implement a prototype tool for the selection of LAN switch according to the suggested selection model and analyse the result. The result of our research is expected to be a useful tool for decision making to evaluate and select the LAN switch and also can be applied to the decision making of evaluation and selection related to the product of computer network with QoS.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.11a
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• pp.139-144
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• 2003

Mobile Node has to maintain communication as they move form place to place, so it doesn't guarantee Quality of Service(QoS). Fast Handoff is important to provide multimedia and real-time applications services in mobile, and it is closely related to handoff delay. Therefore, handoff delay problem is actively studied to quarantee QoS as a main issue in mobile IP research area. Next generation Mobile IPv6 resolve this problem somewhat, triangle problem for first packet and handoff delay still remain. In this paper, we suggest SNMP Information-based routing that adds keyword management method to Information-based routing in active network in order to resolve such a problem, and then suggest QoS controlled handoff based on SNMP Information-Based routing. After modeling of suggested method and existing handoff method, simulations are carried out with NS-2 for performance evaluation. The results of simulations show the some improvement on handoff delay, and therefore on QoS improvement.

• Journal of Internet Computing and Services
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• v.8 no.5
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• pp.109-116
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• 2007

Nowadays, with the proliferation of Web services, developer and user can implement a complex application by composing registered Web services. In this trend, the quality of service of a composite Web service is of crucial importance for today's Service Oriented Computing (SOC) environment. But the global optimization of a composite Web service satisfying given QoS is classified to NP-hard problem. To solve this problem, we propose K-way Super node approach and show the effect of it from experimental results.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.5
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• pp.619-627
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• 1999

To support multimedia services between network domains with different environments, it is required to map the functionalities in many aspects. In this paper, we implemented interworking gateway which provides protocol conversion and QoS(Quality of Service) adaptation to interwork DAVIC services based on ATM(Asynchronous TRansfer Model )network and Internet AV services. The interworking gateway converts RTSP(Real-Time Streaming Protocol ) message into DSM-CC(Digital Storage Media Command & Control) messages to control the stream that is served in ATM network, and transmits data stream by using RTP(Real-Time Transport Protocol) The interworking gateway provides QoS adaptation functionalities by QoS monitoring and MPEG filtering to meet the variation of network bandwidth.

• Journal of Advanced Navigation Technology
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• v.12 no.6
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• pp.591-597
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• 2008

With the established voice service, the data service is increasing in the field of mobile telecommunications in these days. Also, the data service develops into the form of multimedia service which combines various media. However, it is limited to provide QoS(Quality of Service) for the multimedia using the established network which manages all the data in sam: rule. So, this paper suggests the network architecture which assures QoS of multimedia data by applying MPLS(Multi-Protocol Label Switching) to the core network. Especially, we analyze the efficiency of the network combining Mobile IP network based on the WLAN(Wireless LAN) and core network based on MPLS through by network simulations using QualNet.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.655-664
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• 2002

The focus of quality-of-service routing has been on the routing of a single path satisfying specified QoS constraints. However upon failure of a node or link on the path, a new path (backup path) satisfying the constraints has to be established. This paper proposed the fault recovery QoS Rerouting algorithms to recovery the service of applications under fault environment of network. For this, we describes the generation method of PFC (Protection Fundamental Cycle) protecting all of network nodes and suggests path selection algorithms using minimization rerouting cost problem and analyzes the performances of these.

• Convergence Security Journal
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• v.6 no.2
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• pp.61-69
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• 2006

For the efficient business, the telecommunication providers should have an attention for the minimization of the basic setup cost to implement the network infrastructure. Furthermore, the provision of the quality of service (QoS) to the service users is crucial for the service providers and vendors. In this paper, we propose the new algorithm to provide the user's QoS under the various traffic in the broadband convergence network. Using the NS-2 network simulator, we evaluate the QoS for the proposed algorithm, and compare those with the results of the previous differentiated service network.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.6
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• pp.1152-1168
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• 2010

Recently, due to the prevalence of various mobile devices and wireless broadband networks, there has been a significant increase in interest and demand for multimedia streaming services such as the mobile IPTV. In such a wireless broadband network, transmitting a continuous stream of multimedia data is difficult to achieve due to mobile stations (MSs) movement. Providing Quality of Service (QoS) for multimedia video streaming applications requires the server and/or client to be network-aware and adaptive. Therefore, in order to deploy a mobile IPTV service in wireless broadband networks, offering users efficient wireless resource utilization and seamlessly offering user perceived QoS are important issues. In this paper, we propose a new adaptive streaming scheme, called MARC (Mobile-aware Adaptive Rate Control), which adjusts the quality of bit-stream and transmission rate of video streaming based on the wireless channel status and network status. The proposed scheme can control the rate of multimedia streaming to be suitable for the wireless channel status by using awareness information of the wireless channel quality and the mobile station location. The proposed scheme can provide a seamless multimedia playback service in wireless broadband networks in addition to improving the QoS of multimedia streaming services. The proposed MARC scheme alleviates the discontinuity of multimedia playback and allocates a suitable client buffer to the wireless broadband network. The simulation results demonstrate the effectiveness of our proposed scheme.

• Annual Conference of KIPS
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• 2001.04a
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• pp.487-490
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• 2001

Mobile IP는 HA(Home Agent)와 FA(Foreign Agent)간의 터널링을 이용하여 IP망에서 단말기의 이동성을 지원하는 표준 프로토콜이다. 하지만 이러한 터널링 방법은 현재 제안되고 있는 인터넷 서비스 연구 즉 통합 서비스(Integrated Service) 및 차별화 서비스(Differentiated Service) 등을 적용하기 위해서는 많은 문제점을 가진다. 대표적인 문제점은 통신망에서는 전송되는 IP 패킷의 헤더에 의해서 세션을 구별하게 되는데 터널링 패킷의 경우 실제 세션과 다른 헤더를 사용하므로 망에서 세션에 대한 처리를 하기 위해서는 내재된 패킷의 정보가 터널링 패킷의 헤더에 반영되어야 한다. 본 논문은 이러한 문제점을 도메인 게이트웨이 라우터에 HA/FA 기능을 추가하는 동시에 RSVP(Resource Reservation Protocol) 플로우를 군집하는 도메인 레벨 QoS(Quality of Service)와 이동성 지원 프로토콜에 QoS를 의존하는 마이크로 레벨 QoS를 분리하는 이단계 구조를 통해 단-대-단 QoS를 보장할 수 있는 방안을 제안한다.