• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10B
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• pp.866-871
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• 2006

This paper presents the design of a reservation-based MAC protocol to support multimedia traffic over mobile ad-hoc networks and evaluates its performance. Our MAC protocol is based on a hierarchical approach consisting of two sub-layers. The lower sub-layer of the MAC protocol with reservation provides a fundamental access method using CSMA/CA in order to support asynchronous data traffic over mobile ad-hoc networks. The upper sub-layer supports real-time periodic data by making a slot reservation before transmitting actual data. The proposed protocol has been validated through simulations using ns-2. The results show that the proposed MAC protocol can offer higher throughput and lower delay than standard implementations of the IEEE 802.11.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.449-454
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• 2008

As demand for the application in multimedia networks is increasing rapidly, it is important to provide these services in Mobile Environments (ME). Obtaining to multimedia services which satisfy synchronization constraints in ME and improving the delay time and Quality of Service(QoS) between media streams to be presented, new specification model has to be proposed. In this paper we propose Mobile Synchronization Model(MSM) as a new specification model for describing efficiently the QoS and the delay time. Also, we propose the multimedia synchronization algorithm where is a dynamic synchronization method that minimizes the effects of adaptive transmission delay time. The proposed model has higher the guarantee of QoS such as the loss rate and the playout rate than it of the previous work.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.659-667
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• 2009

Mobile Ad-hoc Network consists of mobile nodes without immobile base station. In mobile ad-hoc network, network cutting has occurred frequently in node because of energy restriction and frequent transfer of node. Therefore, it requires research for certain techniques that react softly in topology alteration in order to improve reliability of transmission path. This paper proposes path selection techniques to consider mobility of node that respond when search path using AOMDV routing protocol. As applying proposed techniques, We can improve reliability and reduce re-searching number of times caused by path cutting.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.109-112
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• 2005

As the degree of use of network is increasing the need for building the basic of the stable network service is being needed a lot. Also the engineers require the traffic control for the best application and management and bandwidth management urgently. To solve these problems, there were no other ways of increasing the bandwidth of lines until now. However, this solution has the limit that the cost is too high and the traffic problem is growing continuously. On this study, it is suggested that through the planning the wired /wireless combination network design offering the service of QoS, Multicast, Mobile, realtime multimedia traffic delay without packet loss will be dealth with.

• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.1-14
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• 2002

The most important issue in providing multimedia traffic on a mobile computing environments is to guarantee the mobile host(client) with consistent QoS(Quality of Service). However, the QoS negotiated between the client and network in one cell may not be honored due to client mobility, causing hand-offs between cells. In this paper, a call admission control mechanism is proposed to provide consistent QoS guarantees for multimedia traffics in a mobile computing environment. Each cell can reserve fractional bandwidths for hand-off calls to its adjacent cells. It is important to determine the right amount of reserved bandwidth for hand-off calls because the blocking probability of new calls may increase if the amount of reserved bandwidth is more than necessary. An adaptive bandwidth reservation based on an MPP(Mobility Pattern Profile) and a 2-tier cell structure has been proposed to determine the amount of bandwidth to be reserved in the cell and to control dynamically its amount based on its network condition. We also propose a call admission control based on this bandwidth reservation and "next-cell prediction" scheme using an MPP. In order to evaluate the performance of our call admission control mechanism, we measure the metrics such as the blocking probability of our call admission control mechanism, we measure the metrics such as the blocking probability of new calls, dropping probability of hand-off calls, and bandwidth utilization. The simulation results show that the performance of our mechanism is superior to that of the existing mechanisms such as NR-CAT1, FR-CAT1, and AR-CAT1.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.253-260
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• 2007

A multimedia converter is used to create media suitable for own environment. If the data complying with own demands can not be created, it may accompany with a problem that has to convert the data with another transcoder. In addition, conventional converters do not consider source QoS and target QoS sufficiently, meaning that users should have a significant knowledge base about various media in order to obtain desired results. These problems become limits on the UMA(Universal Multimedia Access) environment. In this paper, we create a suitable transcoding path before performing the Digital Item conversion in consideration of source QoS and target QoS. The created transcoding path performs the adaptive transcoding using unit exchanges featuring connectivity. The consideration of QoS allows users to use the multimedia easily. Since the proposed model, in addition, use the unit transcoder, it provides a excellent adaptive capability for new QoS.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.884-888
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• 2009

Vehicular Adhoc Networks (VANET), a Vehicle-to-Infrastucture or Vehicle-to-Vehicle communication technology, is an area that makes more specific use of Mobile Adhoc Networks(MANET). VANET's Quality of Service(QoS) focuses on preventing possible emergencies like car crash from happening by immediately transmitting information to the cars around, while MANET's QoS is being studied for the quality of multimedia data such as Video on Demand(VoD), Video streaming, Voice over IP(VoIP), etc. In this paper, I structure the actual network configuration using Link State Routing(LSR), implement QoS Provisioning Model using Common Open Policy Service(COPS), and suggest more effective k-hop Cluster and inter-domain policy negotiation which fit better to the characteristics of VANET.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.112-114
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• 2003

현재 네트워크 시스템 구조는 고정된 호스트에게 실시간 서비스를 제공할 수 있지만, MH(Mobile Host)가 빈번하게 이동하는 이동 컴퓨팅 환경에는 높은 수준의 QoS(Quality of Service)를 제공하지 못한다. 이러한 문제를 해결하기 위해 본 논문은 Mobile IP와 Cellular IP 통할 환경에서 MH의 핸도오프를 내부영역 핸드오프(intra­domain handoff)와 외부영역 핸드오프(inter­domain handoff)로 나누어 실시간 서비스를 제공하기 위한 자원 예약 기법을 제안한다. 이 예약 기법은 MH의 이동에 관계없이 높은 수준의 QoS를 제공할 수 있고, Mobile IP 네트워크 영역의 부하를 줄일 수 있는 장점이 있다.

• Journal of the Korea Society for Simulation
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• v.13 no.4
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• pp.55-69
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• 2004

In MANET(Mobile Ad-hoc Network), unlike in wired networks, a path configuration should be in advance of data transmission along a routing path. Frequent movement of mobile nodes, however, makes it difficult to maintain the configured path and requires re-configuration of the path very often. It may also leads to serious problems such as deterioration of QoS in mobile ad-hoc networks. In this paper, we proposed a Reactive Routing Keyword (RRK) routing procedure to solve those problems. Firstly, we noticed it is possible in RRK routing to assign multiple routing paths to the destination node. We applied this feature into active networks and SNMP information based routing by storing unique keywords in cache of mobile nodes corresponding to present and candidate routings in a path configuration procedure. It was shown that the deterioration of QoS which may observed in Dynamic Source Routing(DSR) protocol was greatly mitigated by using the proposed routing technique.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.4886-4907
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• 2019

The use of mobile devices is increasing in multimedia applications. The multimedia contents are delivered to mobile users over heterogeneous networks. Due to fluctuation in bandwidth and user mobility, the service providers are facing difficulties in providing Quality of Service (QoS) guaranteed delivery for multimedia applications. Multimedia applications depend on QoS parameters such as delay, bandwidth, and jitter to offer better user experience. The existing schemes use the single source and multisource delivery but are unable to balance between stream quality and network congestion for mobile users. We proposed a Quality Oriented Multimedia Content Delivery Scheme (QOMCDS) for the mobile cloud to deliver better quality multimedia contents for the mobile user. The multimedia contents are delivered to the mobile device based on the device's parameters and network environment. The objective video quality assessment models like Peak Signal-to-Noise Ratio (PSNR), Structural Similarity (SSIM), and Video Quality Measurement (VQM) are used to measure the quality of the video. The client side Quality of Experience metric such as Startup delay, Rebuffering events, and Bitrate switch count was used for evaluation. The proposed scheme is evaluated using dash.js and is compared to existing schemes. The results show significant improvement over existing multimedia content delivery schemes.