• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.246-251
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• 2013

In this paper, it is proposed a bandwidth allocation Scheme based on Bankruptcy theory in Distributed Mobile Multimedia Network. The proposed scheme is guaranteed a minimum allocation. So, the minimum quality of each service are guaranteed. Therefore efficient and fairness network can be configured. The performance evaluation results indicate that the proposed scheme has good performance than other existing schemes by the fairness index and the Erlang blocking formular calculation. The minimum bandwidth of the proposed scheme can be applied to other techniques of a priority based bandwidth allocation scheme and dynamic bandwidth allocation scheme.

• Journal of Korea Multimedia Society
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• v.17 no.4
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• pp.526-534
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• 2014

Most of the multiplayer games available online are based on a client-server architecture because this architecture gives better administration control to the game providers than peer-to-peer architecture. In this architecture, the server is responsible for all the communication between the connected clients. The weakness of this architecture is its bandwidth requirement and scalability. Peer-to-peer architectures have then been proposed to solve these issues. In this paper, we propose a hybrid client-server architecture in which the game state is partially shared by the mobile terminal to achieve consistency among different players. Like a peer-to-peer architecture, this architecture uses client-side capacities to reduce bandwidth requirements for the server and improves consistency in wireless networks. Client events have different timeliness and consistency requirements according to their nature in the game world. These requirements lead to tasks with different priorities on CPU processing. In the proposed architecture, either the server or the client applies consistency mechanism according to the priority level. Simulation experiments show that the bandwidth of the server in this architecture is smaller than that of the client-server architecture. As a result, the server in the proposed architecture can accommodate more clients with enhancing the scalability.

• ETRI Journal
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• v.35 no.2
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• pp.234-244
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• 2013

Internet protocol television (IPTV) service depends on the network quality of service (QoS) and bandwidth of the broadband service provider. IEEE 802.16j mobile multihop relay Worldwide Interoperability for Microwave Access networks have the opportunity to offer high bandwidth capacity by introducing relay stations. However, to actually satisfy QoS requirements for offering IPTV services (HDTV, SDTV, Web TV, and mobile TV) for heterogeneous users' requests, providers must use a video server for each IPTV service type, which increases the network load, especially bandwidth consumption and forwarding time. In this paper, we present a solution for forwarding IPTV video streaming to diverse subscribers via an 802.16j broadband wireless access network. In particular, we propose a new multicast tree construction and aggregation mechanism based on the unique property of prime numbers. Performance evaluation results show that the proposed scheme reduces both bandwidth consumption and forwarding time.

• 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.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.553-556
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• 2002

인터넷과 World Wide Web의 폭발적인 성장은 네트워크에 많은 정보와 리소스를 제공하고 있다. 그렇지만, 대부분의 사용자들에게 있어서 인터넷 리소스의 사용은 Bandwidth에 의하여 많은 제한을 받고 있다. 그러나 애플릿 방식을 통해서 HTML이 가지고 있는 정적인 면과 CGI의 bandwidth에 따르는 성능 저하 문제를 해결할 수 있다. Mobile Agent는 사용자의 특정 목적을 성취하기 위해서 사용자의 컴퓨터에서 출발하여 네트워크를 이동하면서 작업을 수행한다. 이렇게 수행할 수 있는 코드가 네트워크를 통하여 전송되고, 네트워크에서 수행되기 때문에, 자연스럽게 mobile code의 보안에 중요한 문제가 발생한다. 본 연구에서는 이러한 Mobile Agent를 사용하는 분산 웹 환경에서, Mobile Agent를 호스트와 Agent를 보호할 수 있는 방안을 모색보고, Mobile Agent 의 개념과 Mobile Agent를 구성하면서 생기는 문제를 기술하고, 이러한 문제를 해결하기 위해서 연구중인 방법을 제시하고, 제시된 방법 중에서 현실적으로 적용 가능한 방법을 사용하여 이동 에이전트의 보안 시스템을 설계해 보도록 한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.259-262
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• 2003

인터넷과 World Wide Web의 폭발적인 성장은 네트워크에 많은 정보와 리소스를 제공하고 있다 그렇지만, 대부분의 사용자들에게 있어서 인터넷 리소스의 사용은 Bandwidth에 의하여 많은 제한을 받고 있다. 그러나 애플릿 방식을 통해서 HTML이 가지고 있는 정적인 면과 CGI의 bandwidth에 따르는 성능 저하 문제를 해결할 수 있다. Mobile Agent는 사용자의 특정 목적을 성취하기 위해서 사용자의 컴퓨터에서 출발하여 네트워크를 이용하면서 작업을 수행한다. 이렇게 수행할 수 있는 코드가 네트워크를 통하여 전송되고, 네트워크에서 수행되기 때문에, 자연스럽게 mobile code의 보안에 중요한 문제가 발생한다. 본 연구에서는 이러한 Mobile Agent를 사용하는 분산 웹 환경에서, Mobile Agent를 호스트와 Agent를 보호할 수 있는 방안을 모색보고, Mobile Agent 의 개념과 Mobile Agent를 구성하면서 생기는 문제를 기술하고, 이러한 문제를 해결하기 위해서 연구중인 방법을 제시하고, 제시된 방법 중에서 현실적으로 적응 가능한 방법을 사용하여 이동 에이전트의 보안 시스템을 설계해 보도록 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.3
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• pp.477-493
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• 2011

The IEEE 802.16 mobile multi-hop relay (MMR) task group 'j' (TGj) has introduced the multi-hop relaying concept in the IEEE 802.16 Wireless MAN, wherein a relay station (RS) is employed to improve network coverage and capacity. Several RSs can be deployed between a base station and mobile stations, and configured to form a tree-like multi-hop topology. In such architecture, we consider the problem of a path selection through which the mobile station in and outside the coverage can communicate with the base station. In this paper, we propose a new path selection algorithm that ensures more efficient distribution of resources such as bandwidth among the relaying nodes for improving the overall performance of the network. Performance of our proposed scheme is compared with the path selection algorithms based on loss rate and the shortest path algorithm. Based on the simulation results using ns-2, we show our proposal significantly improves the performance on throughput, latency and bandwidth consumption.

• Journal of Korea Multimedia Society
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• v.13 no.3
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• pp.349-358
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• 2010

Adaptability is an important issue in video streaming over mobile environments, since the clients may request videos with great differences in their workload. In this paper, we propose the issues in limited bandwidth scheduling for efficient MPEG-4 video stream transmission over a mobile or wireless network. In the phase of admission control, the amount of bandwidth allocated to serve a video request is the mean bandwidth requirement of its requested video. The dynamic allocation of bandwidth in the phase of scheduling depends on the playback buffer levels of the clients with an objective to make it more adaptive to the playback situation of individual clients. In the proposed RTA scheduling protocol, more bandwidth may be allocated temporarily to the client whose buffer level is low. By employing the buffer level based scheduling policy, this protocol attempts to maximize the real-time performance of individual playback while minimizing the impact of transient overloading. Extensive simulation experiments have been performed to investigate the performance characteristics of the RTA protocol as comparing with BSBA protocol. This RTA protocol shows the better performance by transferring more frames than BSBA protocol.Computer simulations reveals that the standard deviation of the bit rate error of the proposed scheme is 50% less than that of the conventional method.

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.379-388
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• 2007

With proliferation of computer and wireless network technology, it is common to access Internet through wireless network using mobile device. Ratio of using streaming media out of many applications through Internet is increasing not only in wired network but also in wireless network. Streaming media is much bigger than other contents and requires more network bandwidth and more computing resources. However mobile devices hate relatively poor computing resource and low network bandwidth. If media streaming service is provided for mobile devices without any consideration about network bandwidth and computing power, it is hard for the client to get high qualify service. Since mobile device is supported with very limited energy from the battery, media streaming should be adjusted to varying energy state of mobile device in realtime to ensure complete playback of streaming media. In this paper, we propose DFRC to provide high qualify service to mobile client through wireless network by controlling the number of frames transmitted to client based on computing resource and energy state of mobile device.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.3
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• pp.141-144
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• 2015

A broadband radio frequency synthesizer for multi-band, multi-standard mobile DTV tuners is proposed, it's loop bandwidth can be calibrated to optimize integrated phase noise performance without the problem of phase noise peaking. For this purpose, we proposed a new third-order scalable loop filter and a scalable charge pump circuit to minimize the variation in phase margin during calibration. The prototype phase-lock loop is fabricated in 180nm complementary metal-oxide semiconductor shows that it effectively prevents phase noise peaking from growing while the loop bandwidth increases by up to three times.