• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.11
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• pp.2498-2511
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• 1997

Due to the recent advances in computer technologies and high-speed networks, telecommunication services and provision of multimedia services will be considered a new software architecture adapting networking infrastructure on information networking architecture. In this paper, the video conference services has been selected as a target service example because it is expected to become one of the most important services on the full service network. In fact, it can be viewed as the basis for providing telecommunication services such as video telephony and video conferencing. This paepr presents the prototyping of TINA(Telecommunication Information Networking Architecture) based desktop video conference system using the concepts of session management. The prototyping of deskop video conference system aims at assessing TINA concepts and refinement of the mapping between session graph and connection graph, and provides support of open service platform towards distribution and objected-orientation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1191-1199
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• 2009

As the Internet service evolves from the best effort data service to a multimedia service such as a mix of voice, data and video, a need for the guarantee of the quality of service to network services became one of the hot issues for the network operators. On the other hand, the introduction of the multimedia services over the IP network requires a managed differentiated service that adopts a prioritized treatment of packets. This incurs a need for a differentiated pricing scheme for the packets that receive different level of quality of service. This work proposes an analytic framework about packet pricing scheme for these services, and investigate the effect of service differentiation to the packet price for each class. Via numerical experiment, we validate our argument and illustrate the implication of the work.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.34-40
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• 2018

In this study, the optimal buffer size is calculated for seamless video playback on a mobile device. Buffer means the memory space for multimedia packet which arrives in mobile device for video play such as VOD service. If the buffer size is too large, latency time before video playback can be longer. However, if it is too short, playback service can be paused because of shortage of packets arrived. Hence, the optimal buffer size insures QoS of video playback on mobile devices. We model the process of buffering into a discret-time queueing model. Mean busy period length and mean waiting time of Geo/G/1 queue with N-policy is analyzed. After then, we uses the main performance measures to present numerical examples to decide the optimal buffer size on mobile devices. Our results enhance the user satisfaction by insuring the seamless playback and minimizing the initial delay time in VOD streaming process.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2B
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• pp.334-344
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• 2010

Recently, due to the prevalence of various mobile devices and broadband wireless networks, a significant interests and demands for multimedia streaming services over the Internet have been increasing. However, it is difficult to transmit continuous multimedia stream when mobile terminals are moving. Therefore, in order to deploy mobile IPTV service in the broadband wireless network, efficient wireless resource utilization and seamless QoE (Quality of Experience) offers to the users are an important issue. In this paper, we propose a network based adaptive streaming scheme, called MARC (Mobile Adaptive Rate Control), which controls the quality of the video and rate of the video based on the status of the wireless channel. The proposed scheme uses awareness information of the wireless channel status and controls transmitting streaming video which is suitable for the wireless channel status and mobile station location, in order to provide a seamless video playback for mobile environment in addition to improving the quality of a streaming service. The proposed MARC scheme alleviates the discontinuity of video playback and allocates suitable client buffer in broadband wireless network. Simulation results demonstrate the effectiveness of our proposed scheme.

• Journal of Korea Multimedia Society
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• v.15 no.5
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• pp.577-586
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• 2012

The smartphone emerged due to the rapid development of the Internet has brought greater convenience to life in a positive manner. Recently, however, because of unconstrained exposure to harmful video, reckless use of smart phones has become a domestic issue in our society. In this paper, a service which detects harmful videos by using the acoustic information is designed and implemented on the Android OS. In order to implement the service of Android OS-based detection of the harmful movie, the speed of existing sound-based detection method for harmful videos is improved. The GMM(Gaussian Mixture Model) was used for classifier and the number of Gaussian Mixture was 18. The implemented service shows a detection rate of 97.02% for a total of 1,210 data files (approximately 687 hours) which comprises 669 general videos files (about 424 hours) and 541 harmful video files (about 263 hours). It's speed is 5.6 times faster than the traditional methods whitout reducing the detection rate.

• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1264-1273
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• 1998

In this paper, we implemented a system which provides more effective conference control than that of video conferencing system has been used on MBone. The system provides multicast service on the non-broadcasting network. It multicasts multimedia data using several MTS(Multipoint Transport Server)s and provides a tightly coupled conference control service with a CCS(Conference Control Server). As providing a tightly coupled conference control service, we can perform effectively video conferencing using this system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11B
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• pp.968-980
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• 2008

Providing handover with guaranteed QoS for real-time multimedia service such as VoIP, video/audio streaming, and video conferencing in wireless LAN is a challenging task. In this paper, we present efficient layer 2 handover mechanism in wireless LAN, which can provide fast handover with guaranteed QoS for real-time multimedia service. To this end, the scanning period and the number of channels per scanning for handover are dynamically adapted to the type of applications and wireless networking environment, so that both the degradation of application service quality and signaling overhead are minimized simultaneously. The performance of the proposed mechanism is verified by the simulation. The simulation results show that the proposed mechanism guarantess QoS of each multimedia application with minimal power consumption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8B
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• pp.1150-1158
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• 2010

At present multimedia service composed of voice, data, and video service is prevalent in the Internet. As such, wide-scale penetration of Internet service imposes tremendous pressure to the network infrastructure such as the media servers and links as well as the nodes. In addition, users from a large-scale population require broad bandwidth and high level of QoS. This requires a network with reliable and scalable services to customers, which also necessitates a realistic method for the design of the a media server. In this work, we explore the influence of user's behavior about delay on the performance of media server that takes into account the system and user attributes in a realistic manner. By incorporating user's behavior about the delay-sensitivity, we present an analytic framework for the evaluation of the performance of the media server, via which we illustrate a meaningful intuition in the provision of Internet multimedia service.

• The KIPS Transactions:PartB
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• v.17B no.6
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• pp.413-420
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• 2010

In this paper, we propose a scheme for dynamic allocating network bandwidth based on the playback buffer levels of the clients in a distributed mobile multimedia system. In this scheme, the amount of bandwidth allocated to serve a video request depends on the buffer level of the requesting client. If the buffer level of a client is low or high temporarily, more or less bandwidth will be allocated to serve it with an objective to make it more adaptive to the playback situation of this client. By employing the playback buffer level based bandwidth allocation policy, fair services can also be provided to the clients. In order to support high quality video playbacks, video frames must be transported to the client prior to their playback times. The main objectives in this bandwidth allocation scheme are to enhance the quality of service and performance of individual video playback such as to minimize the number of dropped video frames and at the same time to provide fair services to all the concurrent video requests. The performance of the proposed scheme is compared with that of other static bandwidth allocation scheme through extensive simulation experiments, resulting in the 4-9% lower ratio of frames dropped according to the buffer level.

• Journal of Digital Contents Society
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• v.11 no.4
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• pp.579-588
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• 2010

Generalization of the web, development of one-person media such as the blog and mini homepage, and integration of video digital devices have generalized multimedia video services on the web. However, flash videos, the previously used bit map-based multimedia videos, exhibit problems like the waterfall phenomenon, lag phenomenon, or non-synchronization of audios or videos. Thereupon, This study is conducted to suggest a converting technique to provide efficient web video service on the web by solving problems of bitmap-based flash video through file format-converting software and movie editing programs. And this paper also conducts experiments on five videos for 13 CODECs and analyzes converted results comparatively. The recommendable method considering the characteristics of each videos is to utilize MainConcept H.264 Video CODEC using SWF2Video pro. The result of this research can be used to produce web videos on the web more effectively.