• Journal of the Korea Society of Computer and Information
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• v.4 no.4
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• pp.101-112
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• 1999

In this paper variable bit rate VBR Moving Picture Experts Group (MPEG) coded full-motion video traffic is modeled by a nonlinear time-series process. The threshold autoregressive (TAR) process is of particular interest. The TAR model is comprised of a set of autoregressive (AR) processes that are switched between amplitude sub-regions. To model the dynamics of the switching between the sub-regions a selection of amplitude dependent thresholds and a delay value is required. To this end, an efficient and accurate TAR model construction algorithm is developed to model VBR MPEG-coded video traffic. The TAR model is shown to accurately represent statistical characteristics of the actual full-motion video trace. Furthermore. in simulations for the bit-loss rate actual and TAR traces show good agreement.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.217-220
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• 2000

This paper studies a real-time VBR traffic characterization. There are two big approaches to determine traffic. One is a statistic approach and the other is a deterministic approach. This paper proposes a new constraint function, what we called “Sub-Sum Constraint Function”(SSCF). This function is mainly based on a deterministic approach and uses a statistic approach. It predicts and calculates the next rate with a present information about the stream. SSCF captures the intuitive bounded by a rate lower than its peak rate and closer to its long-term average rate. This model makes a order of the constraint function much less than any other works (O(n)). It can also be mapped on a token bucket algorithm which consists of r (token rate) and b (token depth). We use a concept, EB(effective bandwidth) for a utility of our function and comparing with other techniques such as CBR, average VBR. We simulated 21 multimedia sources for verifying the utility of our function.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.301-303
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• 2004

In this work, we develop on-line traffic prediction algorithm for real-time VBR traffic. There are a number of important issues: (i) The traffic prediction algorithm should exploit the stochastic characteristics of the underlying traffic and (ii) it should quickly adapt to structural changes in underlying traffic. GOP ARIMA model effectively addresses this issues and it is used as basis in our bandwidth prediction. Our prediction model deploy Kalman filter to incorporate the prediction error for the next prediction round. We examine the performance of GOP ARIMA based prediction with linear prediction with LMS and double exponential smoothing. The proposed prediction algorithm exhibits superior performam againt the rest.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.591-596
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• 1999

In this paper, we present a joint quality control system to be able to accurately control the relative picture quality among the video programs in terms of PSNR. The joint quality control system allows variable bit rate (VBR) for each video program to maintain the pre-determined relative picture quality among the aggregated video programs while keeping a constant sum of the bit rates for all programs to be transmitted over a single constant bit rate (CBR) channel. This is achieved by simultaneous controlling the video encoders to generate VBR video streams at the central controller. Furthermore we also suggest buffer regulation method based on the analysis of the constraints imposed by sender/receiver buffer sizes and total transmission rate. Through various simulation results, it is found that our quality control systems guarantee that the video buffers do not overflow and underflow and the quality control errors do not exceed 0.1 ㏈.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.605-607
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• 1999

직렬 버스는 예약 대역폭을 보장해 주는 등시성 전송모드를 제공하고 있지만 실시간 가변비트율(VBR)의 데이터를 전송할 경우 많은 대역폭이 낭비되는 문제점을 가지고 있다. 본 논문은 이러한 문제를 개선하기 위하여 예약된 등시성 전송에는 영향을 주지 않으면서 남아있는 가용 등시성 대역폭을 이용하여 실시간 VBR 데이터를 효과적으로 전송하는 기법에 대한 것이다. 제안된 전송기법의 유용성을 확인하기 위하여 자체 개발한 1394 버스 시뮬레이터상에서 다수의 MPEG 비디오 데이터를 가지고 실험을 하였다. 실험 결과, 제안기법을 사용할 경우 전송 지연을 발생시키지 않고 등시성 대역폭을 평균 비트율 수준까지 낮추어 할당할 수 있음을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1071-1074
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• 2000

본 연구는 멀티미디어 트래픽의 하나인 VBR(Variable Bit Rate) 서비스를 위한 무선 단말기의 효율적인 채널 사용을 위한 무선 ATM MAC(Medium Access Control) 프로토콜에 관한 연구이다. 현재 유선망에서는 멀티미디어 서비스를 위하여 ATM 기술을 사용하고 있기 때문에 유무선망의 통합을 위한 ATM 무선망의 설계가 대두되고 있다. 이를 위해서는 무선망이 가지는 대역폭의 한계와 링크의 높은 에러율을 극복하기 위해서 효율적인 MAC 알고리즘 개발이 필요하다. 본 논문에서는 무선 ATM망에서 VBR 트래픽 소스를 갖는 단말기의 QoS를 보장하고 채널 사용의 효율을 높이기 위하여 신경망을 이용한 Neural DSA(Dynamic Slot Assignment) 알고리즘을 제안하고 시뮬레이션을 통해 기존에 제안된 MAC 알고리즘과 성능 비교 분석을 통해 그 우수성을 확인하였다.

• Journal of the Korea Society of Computer and Information
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• v.3 no.4
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• pp.132-138
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• 1998

A network of Asynchronous Transfer Mode (ATM) will be required to carry the traffics(CVR, VBR, UBR, ABR) generated by a wide range of services. The traffic ABR uses the remined space of the CBR/VBR traffics bandwith. The Rate-based, the Credit-based, and the mixed method that are implementing the control loop of ABR traffic service is on study. In this paper, a new algorithm that can be considered in ATM and effectively manage ABR traffic using VS/VD method and EPRCA algorithm is proposed on the switch of the Rate-based method

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1910-1916
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• 1999

This paper suggested to solve ATM switch performance and service rate which was input buffer managed scheme in ATM network with burst traffic characteristics, For this purpose, ATM multiplexer is prepared before sending for handling burst random input traffic to multiplex and then sort based on cell inter-arrival time and cell processing due time which had been marked after that. The server looks for cell header with the most shortest due time and sends it, thus it is satisfied that real time traffic for instance CBR and rt-VBR was guaranteed cell processing time to send fast than non real time traffic. For analysis of ATM switch performance with cell processing due time and priority, each output port has divided into four different virtual buffer and each buffer has assigned different cell inter-arrival time and processing due time according to ATM Forum for example CBT/rt-VBR, nrt-VBR, ABR and UBR and showed it’s optimal service parameters then analyzed service rate behaviors according to each traffic characteristics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.142-155
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• 2000

In this paper, we propose an efficient policing mechanism for Markov model-based traffic descriptors of VBR MPEG video traffic. A VBR video sequence is described by a set of traffic descriptors using a scene-basedMarkov model to the network for the effective resource allocation and accurate QoS prediction. The networkmonitors the input traffic from the source using a proposed new policing method. for policing the steady statetransition probability of scene states, we define two representative monitoring parameters (mean holding andrecurrence time) for each state. For frame level cell rate policing of each scene state, accumulated average cellrates for the frame types are compared with the model parameters. We propose an exponential bounding functionto accommodate dynanic behaviors during the transient period. Our simulation results show that the proposedpolicing mechanism for Markovian traffic descriptors monitors the sophisticated traffic such as MPEG videoeffectively and well protects network resources from the nalicious or misbehaved traffic.

• The Transactions of the Korea Information Processing Society
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• v.7 no.1
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• pp.200-214
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• 2000

In general, it is difficult to transmit a VBR video like MPEG efficiently since MPEG fames are construct with various size. To solve this problem, some bandwidth smoothing techniques are proposed which is based on the prefetching video data into the client buffer with low bandwidth allocation. However these techniques do not provide efficient bandwidth smoothing technology and transmission technique for interactive video services like VCR-like functionality. In this paper, we propose and evaluated a new bandwidth allocation mechanism for interactive video services which has VBR traffic characteristics such a MPEG. This technique provides VCR-like functionality which is not supported on previous techniques and also maximizes the bandwidth utilization when interactive video services are provided. Through our experimental, we prove that the proposed technique dramatically decreases a traffic and guarantee the continuous playback simulaneously.