• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1B
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• pp.9-18
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• 2006

Advances in wireless network are enabling the development of ubiquitous multimedia services. These multimedia services need efficient platforms to comply with the requirements of mobile computing. We introduce an adaptive service platform based on mobile agent and grid systems while specifying the challenges of ubiquitous multimedia services and focusing on frequent disconnections and scarce resources. We applied our platform to framework RtoA (Ready-to-Attend) which supports mobile users to access compute-intensive multimedia service, specifically, mobile education and video conferencing. RtoA includes hand-off, speaker and listener service which enable people to attend a conference or a class with satisfying quality of multimedia service. ns-2 based simulation verifies that our scheme is an efficient way to reduce energy consumption of mobile devices and to improve the response time of mobile applications.

• 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.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.197-200
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• 2009

Since various type of wireless/mobile network likes WLAN, WIBRO, HSDPA were come to us, technology providing high quality multimedia service while user move are actively researched such as MIH (Media Independent Handover) proposed by IEEE for interworking between heterogeneous network and CMIP (Client Mobile IP), PMIP (Proxy Mobile IP) for mobility. Despite the technology about interworking and handover between heterogeneous network are actively researched, handover decision method need to be researched. In this paper we suggest a simple and effective handover method for high quality multimedia service in real wireless environment. For this, we use MIH+CMIP platform for target multimedia service to make handover decision rule in WIBRO and HSDPA networks. After apply this rule, we verified effectiveness of handover decision method through real test.

• Journal of Korea Multimedia Society
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• v.11 no.6
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• pp.883-890
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• 2008

It becomes enabled to provide variety of multimedia contents through mobile service with the development of high-speed 3rd generation mobile communication and handsets. MMS (Multimedia Messaging Service) can be displayed in the presentation format which is unified the various multimedia contents such as text, audio, image, video, etc. It is applicable as a new type of ubiquitous learning. In this study we propose to design a mobile learning system by providing profiles which meets the standard of CC/PP and by generating multimedia messages based on SMIL language through the adaptation steps according to the learning environment, the content type, and the device property of learners.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1245-1253
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• 2009

Since 2000, the demand for multimedia content consumption has been continuously increasing. The research and standardization for the mobile broadcast service has been done to deliver multimedia contents to the huge number of users with the minimum cost. A few commercial services started after the related standards were released. We call this mobile broadcast service the 1st generation service. Now, many experts are researching and developing the technologies for 3Screens(TV, PC, and Mobile) Services that an user can enjoy multimedia contents at every place with the various networks and devices. To enable this service, two main technical areas exist. The first is a core network technology that can support the various access network and the second is a common application layer technology. To resolve these technical areas, we propose IMS(IP Multimedia Subsystem) based OMA BCAST(Open Mobile Alliance Mobile Broadcast Service Enabler Suite) as the technical solution for 3 Screen Services in the paper. In addition, we propose application layer multicast that is enable to implement IMS based OMA BCAST to the existing network with the minimum cost. Finally, we show how we can save the implementation cost of IMS based OMA BCAST with the simulation results.

• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.29-35
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• 2015

The heterogeneous LTE (Long Term Evolution)-Advanced networks comprising a macrocell and femtocells can provide an efficient solution not only to extend macrocell coverage but also to deal with packet traffics increasing explosively within macrocells. An efficient resource management scheme is necessary to maintain the QoS (Quality of Service) of mobile multimedia services because the LTE-Advanced system should support not only voice but also mobile applications such as data, image and video. This paper proposes a resource management scheme to guarantee QoS continuity of multimedia services and to maximize the resource utilization in OFDMA (Orthogonal Frequency Division Multiple Access) based LTE-Advanced systems. This scheme divides the resources into several service blocks and allocates those resources based on the competition between macrocell and femtocell. Simulation results show that it provides better performances than the conventional one in respect of handover failure rate and blocking rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7B
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• pp.499-506
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• 2005

In this paper, mobile multimedia service is defined as a service which is used for Internet or multimedia contents without regard to place in the mobile or wireless environment. The purpose of this paper is to search consumer's purchase decision factors by means of literature review and expert's opinion and to analyze a purchase decision structure and its weight. Some implications were found. Firstly, mobile multimedia service purchase factors relating to cost and quality are more important than external causes. Secondly, cost is more important than quality, that is different from result of mobile telecommunication and high-speed Internet service. Thirdly, direct effect such as pertinent charging and terminal price is more important than indirect effect such as pricing differentiation. Finally, main features of service such as mobility and contents are more important than additional characteristics such as personalized service.

• Journal of Korea Multimedia Society
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• v.18 no.11
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• pp.1351-1357
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• 2015

This paper proposes and implements a mobile service and web service integration for utilizing public bicycle sharing system NUBIJA. The NUBIJA system is operated by Changwon City, GyeongNam since 2008 and maintains 247 unattended bicycle sharing terminal on the city. Average users per day of the NUBIJA are more than 8,000 and many users want to get more services from their mobile phones. We implemented realtime mobile bicycle rental and return information service. The informations are acquired from each terminal kiosks and we integrated the information and location based services(LBS) on iOS and Android platform. In this paper, we described an integration services between web and mobile application and shows graphical user interface for highly customized on mobile platforms.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.131-139
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• 2007

The recent advance in wireless network technologies has enabled the streaming media service on the mobile devices such as PDAs and cellular phones. Since the wireless network has low bandwidth channels and mobile devices are actually composed of limited hardware specifications, the transcoding technology is needed to adapt streaming media to given mobile devices. Futhermore owing to the diversity of bandwidth in the wireless network by reason of mobile users' movements and environments, it is difficult to provide stable QoS. In this paper, the autonomic multimedia transcoding system is proposed in order for users to provide network adaptive QoS. Our proposed system is based on the estimation of available bandwidth in wireless network for seamless multimedia streaming service. The proposed system is designed and implemented for various mobile clients. In experiments, we evaluate its seamless multimedia streaming and the adaptation transcoding bit rate according to the changes of bandwidth in wireless network.