• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.367-376
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• 1999

A variable bit-rate based video services have much limitation for bandwidth management, since its trarfic has a some variances in frame level. In particular, the bandwidth management for video which has characteristics of VBR traffic such a MPEG video could be more complicated. Also, it is difficult to manage the bandwidth effectively for proving a VCR function from VOD service, since we don't know the traffic variance exactly at that time. In this paper, we proposed the dynamic bandwidth allocation a scheme based on VBR traffic based stored video such as MPEG for interactive video service. This scheme can maximize the given total bandwidth through the prefetch based variable length bandwidth allocation scheme and dynamic bandwidth management scheme for multiple streams. Also, our scheme can be used for a MPEG-based bandwidth allocation scheme, and provides the method that can maximize the utilization of network resource for multiple stream by using a dynamic bandwidth management.

• The KIPS Transactions:PartC
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• v.18C no.6
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• pp.433-440
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• 2011

In this paper, we propose a new scheduling method that can guarantee reliable jitter by minimizing the queue length variation in the streaming service provisioning such as IPTV and VoD. The amount of traffic to be delivered within a certain time is very fluid because MPEG-4 and H.264 encoders use VBR(Variable Bit Rate) for delivering video streaming traffic. This VBR characteristic increases the end-to-end propagation delay variation when existing scheduling methods are used for delivering video frames. Therefore, we propose the new scheduling method that can minimize change rate of queue length by adaptively controling service rate taking into account the size of bulk incoming packets and arrival rate for bulk streaming traffic. Video frames can be more reliably transmitted through the minimization of the queue length variation using the proposed method. We use the queueing model and also carry out OPNET simulation to validate the proposed method.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.80-91
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• 2002

A general goal of the AT%(Asynchronous Transfer Mode) network is to support connect across various network. On ATM networks, ABR services are provided using the remained ban after allocation CBR and VBR traffic. Realtime services such as transmitting audio or video data may be provided using CBR ado VBR which have a constrained transmission delay, but in these cases, the communications bandwidth may be wasted. In this paper a simulation has been performed to compare and evaluate the performance between the ERICA(Explicit Rate Indicate Avoidance) and EPRCA(Enhanced Proportional Rate Control Algorithm) switches which use Explicit Rate switch algorithm for ABR switch. The variation of the ACR at the source end system, the queue length, the utilization rate of the link bandwidth and the share fairness at the transient and steady states are used as the evaluation criteria for the simulation. As a result of simulation, ERICA algorithm switch was ten times long compared to ERPCA switch to achieve assigned fair share. so EPRCA switch is superior to ERICA about load response. For Fair share and stability, ERICA switch is excellent to EPRCA switch.

• Smart Structures and Systems
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• v.21 no.1
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• pp.37-51
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• 2018

Tuned Liquid Dampers (TLDs) have gained wide acceptance as a system for structural control and energy dissipation. However, they face limitation caused by low damping in deep water, which affects their efficiency. Another problem with deep water TLDs is that not all water depth participates in energy dissipation. This paper investigated the effect of upper mounted baffles on the effectiveness of TLDs. The Vertical Blockage Ratio (VBR) of baffles ranged from 10% - 90%. The TLD (with and without baffle), structure, and combined structure with TLD (with and without baffles) were subjected to free and harmonic forced vibrations. Results indicated that baffles could significantly enhance the energy dissipation of TLDs, thus reducing structural responses more than structures equipped with ordinary TLDs. It was found that, there was an optimum value of VBR in which the TLD's efficiency was maximized. When TLD had an appropriate VBR, the structural acceleration and displacement responses were suppressed significantly up to 51% and 56%, respectively.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.189-198
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• 2001

In recent years, the predominant part in telecommunications is mobile communications. The next generation network is extending today's voice-only mobile networks to multi-service networks. ATM Network is possible to carry such multi-media traffic and it will be expect to use wireless ATM for the future mobile access network. One of manly important aspects for the performance of wireless ATM is the Medium Access Control (MAC) protocol. The MAC protocol must be able to satisfyingly handle the different ATM services (CBR, VBR, ABR and UBR) with their radically different performance requirements. Additionally, the MAC protocol must be able to cope with the complex radio environment where fading, multi-path propagation interference and burst-errors further complicate the situation. In this paper, a dynamic slot allocation algorithm in wireless ATM is proposed for an efficient channel sharing/media access at the MAC layer. We use equivalent capacity in the allocation of slots for VBR traffic which is variable along the time. It is simple and effective slot allocation method for VBR service. In particular, we consider the slot allocation of a session consisted of several connections for requirement of multimedia traffic. Simulation shows that the cell loss ratio is reduced by re-allocation of extra slots in Mobile Terminal (MT).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1554-1559
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• 2000

On ATM networks, MPEG video stream is transferred using CBR or VBR services. But because the MPEG video traffic varies greatly from time to time, it is very difficult to transfer the MPEG steam efficiently without loss of transmission bandwidth. Until now, the study on the traffic analysis and control on a single MPEG video stream has been done by many researchers, but the traffic analysis and control on a multiplexed traffic of multiple MPEG video streams has not been studied by any researcher. This paper proposes a multiplexing method to reduce the PCR and traffic variance of a multiplexed traffic of multiple MPEG video streams. By reducing the PCR of the multiplexed traffic, the multiplexed VBR traffic can be transferred efficiently with less loss of transmission bandwidth.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1994.06a
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• pp.315-319
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• 1994

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.10a
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• pp.302-305
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• 1995

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1996.10a
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• pp.856-859
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• 1996

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1996.10a
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• pp.613-616
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• 1996