• Title, Summary, Keyword: Rate Control

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A Practical TCP-friendly Rate Control Scheme for SVC Video Transport (SVC 비디오 전송을 위한 실용적인 TCP 친화적 전송률 제어 기법)

  • Seo, Kwang-Deok
    • Journal of KIISE:Computing Practices and Letters
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    • v.15 no.2
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    • pp.114-124
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    • 2009
  • In this paper, we propose a practical TCP friendly rate control scheme that considers the minimum channel bandwidth of the network when transporting SVC (scalable video coding) video over IP netowrks such as Internet. RTP and RTCP is mainly designed for use with UDP (User Datagram Protocol) for real-time video transport over the Internet. TCP-friendly rate control was proposed to satisfy the demands of multimedia applications while being reasonably fair when competing for bandwidth with conventional TCP applications. However the rate control model of the conventional TCP-friendly rate control scheme does not consider the minimum channel bandwidth of the network. Thus the estimated channel bandwidth by the conventional rate control model might be quite different from the real channel bandwidth when the packet loss ratio of the network is very large. In this paper, we propose a modified TCP-friendly rate control scheme that considers the minimum channel bandwidth of the network. Based on the modified TCP-friendly rate control, we assign the minimum channel bandwidth to the base layer bitstream of SVC video, and remaining available bandwidth is allocated to the enhancement layer of SVC video for the TCP friendly scalable video transmission. It is shown by simulations that the modified TCP-friendly rate control scheme can be effectively used for a wider range of controlled bit rates depending on the packet loss ratio than the conventional TCP-friendly control scheme. Furthermore, the effectiveness of the proposed scheme in terms of objective video quality is proved by comparing PSNR performance with the conventional scheme.

Rate Modulation Strategy for Behaviors of a Mobile Robot with Considering Control Stability (제어안정도를 고려한 이동로봇 행동단위의 가변 주기 제어)

  • Kim, Hong-Ryeol;Kim, Joo-Min;Kim, Dae-Won;Yang, Kwang-Woong
    • Proceedings of the KIEE Conference
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    • pp.2362-2364
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    • 2003
  • In this paper, behaviors performing controls of a mobile robots are designed based on the concept of closed-loop controls. A control architecture, in which the behaviors coordinate concurrently with one others to achieve a task is also proposed. In the control architecture, task manager allocates valid resources and configures the weight of the behavior outputs to achieve the task. For practical implementation, a rate modulation strategy based on RMS(Rate Modulation Strategy) is proposed for efficient resource allocations. The rate modulation strategy is performed with considering control stability. The efficiency of the proposed rate modulation strategy is validated through simulation tests.

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A Direct Injection-mixing Total-flow-control Boom Sprayer System (주입식 총유량 자동제어방식 분관 방제기의 개발)

  • 구영모
    • Journal of Biosystems Engineering
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    • v.21 no.2
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    • pp.155-166
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    • 1996
  • A direct injection sprayer was designed using the concepts of injection mixing and total flow control, flowrate-based system compensating for the variation of forwarding speed. A metered rate, proportionally to the actual diluent flow rate, of a tracer chemical was injected directly into the diluent stream. The injection of chemical may improve the precision and safety of chemical application process. The control system was evaluated for the variables of the control interval, tolerances and sensitivities of flow regulation valve and injection pump. Performance of the system was assessed as that the response time of flow rate, response time of injection rate, absolute steady state error, and the coefficient of variance(C.V.) of concentration were 8.5 and -0.53 seconds, 0.067 lpm(0.8%) and 3.15%, respectively, at optimal parameters of control interval of 1.0 sec, fast sensitivity of flow regulation valve, medium sensitivity of injection pump and medium tolerance of flow rate. Performance of the system can be improved by increasing the sensitivity of flow regulating valve and employing a high resolution velocimeter, such as Doppler radar.

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Distributed Rate and Congestion Control for Wireless Mesh Networks

  • Quang, Bui Dang;Hwang, Won-Joo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.9A
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    • pp.916-922
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    • 2007
  • Wireless networks (WNs) are developed and applied widely in a lot of areas. Now, a new generation of wireless networks is coming, and that is Wireless Mesh Network (WMN). At present, there are not so many researches which deal on this area. Most researches are derived from Mobile Ad hoc Networks (MANET) and WNs. In WMNs, there are some applications that require real-time delivery. To guarantee this, rate control and congestion control are needed. This problem leads to optimization issue in transport layer. In this paper, we propose a mathematical model which is applied in rate and congestion control in WNMs. From this model, we optimize rate and congestion control in WMNs by maximizing network utility. The proposed algorithm is implemented in distributed way both in links and sources.

Improving Rate Control Algorithm for MPEG 4 Video (MPEG4 Video 부호화를 위한 비트율 제어 알고리즘 개선에 관한 연구)

  • 김소영;박정훈
    • Proceedings of the IEEK Conference
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    • pp.25-28
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    • 2002
  • This paper presents variable bit rate(VBR) rate control scheme based on MPEG-4 VM8 rate control scheme. An initial Q searching method provides more accurate bit allocation for the first frame. A frame skipping and RD Model update scheme when coded frame quality is too low or high prevents image quality fluctuation.

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MPEG-4 Video Rate Control Algorithm using SOFM-Based Neural Classifier (SOFM 신경망 분류기를 이용한 MPEG-4 비디오 전송률 제어)

  • Park, Gwang-Hoon;Lee, Yoon-Jin
    • Journal of KIISE:Software and Applications
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    • v.29 no.7
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    • pp.425-435
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    • 2002
  • This paper introduces a macroblock-based rate control algorithm using the neural classifier based in Self Organization feature Maps (SOFM). In contrast to the conventional rate control methods based on the mathematical rate distortion (RD) model and the feedback regression, proposed method can actively adapt to the rapid-varying image characteristics by establishing the global model for bitrate control and by using the SOFM based neural classifier to manage that model. Proposed rate control algorithm has 0.2 dB ~ 0.6 dB better performances than MPEG-4 macroblock-based rate control algorithm by evaluating with the encoded Peak Signal to Noise Ratios while maintaining similar overall computational complexity.

A hardware design of Rate control algorithm for H.264 (H.264 율제어 알고리듬의 하드웨어 설계)

  • Suh, Ki-Bum
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.1
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    • pp.175-181
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    • 2010
  • In this paper, we propose a novel hardware architecture for Rate control module for real time full HD video compression. In the proposed architecture, QP is updated by using the rate control algorithm to every the macroblock line(120MB for Full HD, 20MB for CIF image). Since there are many complex arithmetic and floating point arithmetic in rate control algorithm of JM for H.264, it is impossible to process the rate control algorithm using the integer arithmetic CPU core. So we adopted floating point arithmetic unit in our architecture, and implemented the rate control algorithm using the floating unit. With this implemented hardware, the implemented hardware is verified to be operated in real time.

Modeling of Multimedia Internet Transmission Rate Control Factors Using Neural Networks (멀티미디어 인터넷 전송을 위한 전송률 제어 요소의 신경회로망 모델링)

  • Chong Kil-to;Yoo Sung-Goo
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.4
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    • pp.385-391
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    • 2005
  • As the Internet real-time multimedia applications increases, the bandwidth available to TCP connections is oppressed by the UDP traffic, result in the performance of overall system is extremely deteriorated. Therefore, developing a new transmission protocol is necessary. The TCP-friendly algorithm is an example satisfying this necessity. The TCP-Friendly Rate Control (TFRC) is an UDP-based protocol that controls the transmission rate that is based on the available round trip time (RTT) and the packet loss rate (PLR). In the data transmission processing, transmission rate is determined based on the conditions of the previous transmission period. If the one-step ahead predicted values of the control factors are available, the performance will be improved significantly. This paper proposes a prediction model of transmission rate control factors that will be used in the transmission rate control, which improves the performance of the networks. The model developed through this research is predicting one-step ahead variables of RTT and PLR. A multiplayer perceptron neural network is used as the prediction model and Levenberg-Marquardt algorithm is used for the training. The values of RTT and PLR were collected using TFRC protocol in the real system. The obtained prediction model is validated using new data set and the results show that the obtained model predicts the factors accurately.

Adaptive digital control system of flow rates for an OTEC plant

  • Nakamura, Masatoshi;Uehara, Haruo
    • 제어로봇시스템학회:학술대회논문집
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    • pp.753-758
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    • 1987
  • The purpose of ocean thermal energy conversion (OTEC) plant control is to provide stable power efficiently by appropriately regulating the seawater flow rates and the working fluid flow rate under conditions of continually changing seawater temperatures. This paper describes digital control of working fluid flow rate based on an adaptive control theory for the "Imari 2" OTEC plant at Saga University. Provisions have been made for linkage between the software of the adaptive control theory and the hardware of the OTEC plant. In implementing the working fluid flow rate control, if persistency of excitation conditions are lost, the algorithm of identification often exhibits bursting phenomena. To avoid this difficulty, the stopping-and-starting rule for identification was derived and was used for the working fluid flow rate control. Satisfactory control performance was then obtained by using this digital control system.ol system.

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Flow Rate Control System Design for the Industrial Valve (산업용 밸브의 유량제어 시스템 설계)

  • Choi, Jeongju
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.1
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    • pp.387-392
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    • 2020
  • This paper proposes a flow-rate control system for industrial valves. Industrial valves are used in piping systems to control the flow rate and pressure. In general, valves used in pipelines are classified into globe valves, butterfly valves, and ball valves according to the shape. Motor, hydraulic, and pneumatic systems are used for operating valves. The flow meter should measure the flow rate when configuring the flow-rate control system. On the other hand, because the flow rate of the valve can be expressed by flow coefficient, a control scheme is proposed using the pressure deviation, which measures at the front and rear of the valve. The transfer function for the valve, according to the control input, was estimated using the signal compression method. Based on the induced transfer function, the disturbance observer was designed to improve the command following the performance of the valve stem. The performance of the proposed control method is compared with the flow-rate control result using the flow meter used.