• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.325-329
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• 2007

The mobile and multimedia service on wireless network have been leaded from the improvement of telecommunication techniques. A typical multimedia service, a video transmission usually requires larger bandwidth than voice transmission. Many channel allocation algorithms for Orthogonal Frequency Division Multiple Access (OFBMA) to use resources more efficiently, Previous channel allocation algorithms have developed with an assumption that the data traffic is constant bit rate (CBR). However, existing algorithms are not suitable to video traffic because it usually generates a variable bit rate (VBR) traffic. In this paper, we proposed a new channel allocation algorithm called a queue-based channel allocation. it is more suitable to transmit the video traffics. Also, a problem are notified in case of realtime generated video traffic and a corresponding heuristic solution was proposed.

• Journal of KIISE
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• v.42 no.8
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• pp.1039-1048
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• 2015

Recently, the web-based adaptive streaming service, DASH (Dynamic Adaptive Streaming over HTTP), is receiving more attention. However, existing network-based and buffer-based video quality control schemes in DASH environments make oscillation of segment throughput, causing degradation of the quality of experience (QoE) with frequent quality changes and playback interruptions because these schemes do not consider the content characteristics. In this paper, we propose a C-DASH (Content Characteristics based Dynamic Adaptive Streaming over HTTP) scheme in order to improve the QoE in DASH environments. The C-DASH scheme performs seamless and smooth quality control based on the segment throughput, buffer status, and segment size of the content. Based on simulation results, it is confirmed that the C-DASH scheme can improve the QoE, when compared with the existing quality control schemes.

• Journal of Internet of Things and Convergence
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• v.8 no.4
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• pp.41-47
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• 2022

Smoothing is a transmission plan that converts video data stored at a variable bit rate into a fixed bit rate. Algorithms for smoothing include CBA, which aims to minimize the number of transmission rate increases, MCBA, which minimizes the number of transmission rate changes, and MVBA algorithms that minimize the amount of transmission rate change. This paper compares the proposed algorithm with the CBA algorithm with various video data, buffer size, and performance evaluation factors as a follow-up to the proposed smoothing algorithm that minimizes (maximizes) the transmission rate increase (decrease) when the server requires more bandwidth The evaluation factors used were compared with the number of changes in the fps rate, the minimum fps, the average fps, fps variability, and the number of frames to be discarded. As a result of the comparison, the proposed algorithm showed superiority in comparing the number of fps rate changes and the number of frames discarded.

• Journal of Internet of Things and Convergence
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• v.8 no.1
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• pp.53-58
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• 2022

Smoothing is a transmission plan that converts video data stored at a variable bit rate into a constant bit rate. In the study of [6-7], when a data rate increase is required, the frame with the smallest increase is set as the start frame of the next transmission rate section, when a data tate decrease is required. the frame with the largest decrease is set as the start frame of the next transmission rate section, And the smoothing algorithm was proposed and performance was evaluated in an environment where network traffic is not considered. In this paper, the smoothing algorithm of [6-7] evaluates the adaptive CBA algorithm and performance with minimum frame rate, average frame rate, and frame rate variation from 512KB to 32MB with E.T 90 video data in an environment that considers network traffic. As a result of comparison, the smoothing algorithm of [6-7] showed superiority in the comparison of the minimum refresh rate.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.3
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• pp.47-61
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• 2012

parallel transmitting system with channel bonding method have been proposed to transmit mass content such as UHD(Ultra High Definition) in HFC(Hybrid Fiber Coaxial) networks. However, this system may lead to channel resource problem because the system needs many channels to transmit mass content. In this paper, we analyze three effective bandwidth approximation algorithms to use the bonding channel efficiently. These algorithms are the effective bandwidth of Gaussian approximation method algorithm proposed by Guerin, the effective bandwidth based on statistics of video frames proposed by Lee and the effective bandwidth based on Gaussian traffic proposed by Nagarajan. We also evaluate compatibility of algorithms to the mass broadcasting service. OPNET simulator is used to evaluate the performance of the algorithms. For accuracy of simulation, we make mass source from real HD broadcasting stream.

• Journal of Korea Multimedia Society
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• v.4 no.1
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• pp.13-28
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• 2001

In a VOD(Vide-On-Demand) system, video data are generally stored in magnetic disk array. In order to provide real-time requirement for data retrieval, video streams must be delivered continuously to the clients such that the delivery of continuous media can be guaranteed in a timely fashion. Compared to the increased performance of processors and networks, the performance of magnetic disk systems have improved only modestly. In order to improve the performance of storage system, disk array system is proposed and used. The array system improves I/O performance by placing disks in parallel and retrieving data concurrently. In this paper, two approaches are considered in order to access the video data in a VOD system, which are CTL(Constant Time Length) and CDL(Constant Data Length) access policies. Disk scheduling policies are also classified into the two categories and compared in terms of the maximum allowable video streams with different degrees of disk array synchronization, under the mixed environments in which both data access policy and disk scheduling policy are considered. Among the compared scheduling policies, LOOK was shown to have the best performance. In terms of degree of disk synchronization, more gain was achieved with large degree of synchronization. In comparisons of performance of CTL and CDL, CTL was proved to have a little superior performance in terms of number of maximum allowable streams.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.1009-1022
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• 2004

Smoothing is a transmission plan where variable rate video data is converted to a constant bit rate stream. Among them are CHA, MCBA. MVBA, e-PCRTT and others. E-PCRTT algorithm, which was improved from PCRTT, restricts the number of rate changes with fixed-size run. This causes unnecessary rate changes and may not guarantee QoS when buffer size is small. In this paper. a smoothing algorithm is pro-posed, where the number of rate changes are not limited and the size of run can be flexible, in order to overcome the shortcomings of e-PCRTT. Experiments demonstrated that the proposed algorithm such as e-PCRTT. In order to show the performance, var-ious evaluation factors were used such as the nember of rate changes, buffer size to maintain QoS, and so on.

• Journal of Internet of Things and Convergence
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• v.7 no.2
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• pp.47-53
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• 2021

In order to transmit video data stored in servers with limited bandwidth in IoT environments to many clients, a transmission plan must be established by considering factors such as the number of transmission rate changes, peak transmission rate, and transmission rate changes. This transmission plan is called smoothing, and includes CBA that minimizes the number of transmission rate increases, MCBA that minimizes the number of transmission rate changes, and MVBA to minimize the transmission rate changes. In this work, to evaluate the performance of the proposed algorithm[16], we compare the proposed algorithm with the existing smoothing algorithms with the peak rate, the number of transmission rate changes, the rate increase, the peak rate utilization, and the average transmission rate with various video data and buffer sizes. The evaluation results show that the proposed algorithm helps to efficiently use the server's finite network resources by establishing a transport plan with the lowest average transfer rate.

• Journal of Internet of Things and Convergence
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• v.9 no.2
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• pp.11-17
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• 2023

Smoothing is to creating a transmission plan consisting of sections of frames that can be sent at the same transmission rate for compressed and stored video data. Various algorithms have been studied for the smoothing to minimize the number of transmission rate changes, the number of transmission rate changes, and the amount of transmission rate increase. This study evaluates the performance of a smoothing algorithm that minimizes the increase in transmission rates and maximizes the increase in transmission rates when the transmission rate is required to maximize the excess bandwidth to be secured by the server in an environment with limited server bandwidth. The available transmission rates and buffer sizes available in the server are set in various ways and evaluated by the number of fps changes, the minimum fps, the average fps, and fps variability. As a result of the comparison, the proposed algorithm showed excellent average fps and fps variability.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.3
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• pp.299-310
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• 2000

In this paper, we designed and implemented a personal VOD server using multi-thread for the real-time services of video data to the users. The system consists of service manager, disk manager, and network manager. The service manager controls the user admission to the system using the VBR(Variable Bit Rate) characteristics of MPEG (Moving Picture Experts Group) video data. The disk manager provides the functions for VCR-like operations. The disk manager reads blocks from the disk by the size of GOP(Group of Pictures) and buffers the data to the user's thread. The network manager uses TCP/IP for the communication between the server and the client. The communication starts from the client and the VOD server must respond to this request. The implemented personal VOD system shows an acceptable performance.