Parallel Implementations of Lambda Domain and R-Lambda Model Rate Control Schemes in a Practical HEVC Encoder

In this paper, the generator angle stability of several active power control schemes of a voltage-source converter (VSC)-based high-voltage DC (HVDC) is evaluated for two interconnected AC systems. Excluding frequency control, there has been no detailed analysis of interconnected grids depending upon the converter power control, so six different types of active power control of the VSC-HVDC are defined and analyzed in this paper. For each TSO (transmission system operator), the applicable schemes of two kinds of step control and four kinds of ramp-rate control with a droop characteristic are included in this research. Furthermore, in order to effectively evaluate the angle stability, the Generators-VSC Interaction Factor (GVIF) index is newly implemented to distinguish the participating generators (PGs) group which reacts to the converter power change. As a result, the transient stabilities of the two power systems are evaluated and the suitable active power control strategies are determined for two TSOs. Simulation studies are performed using the PSS®E program to analyze the power system transient stability and various active power control schemes of the VSC-HVDC. The results provide useful information indicating that the ramp-rate control shows a more stable characteristic than the step-control for interconnected grids; thus, a converter having a certain ramp-rate slope similar to that of the other generator shows more stable results in several cases.

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On error control schemes for ad hoc networks with multiuser detection and rate control

2008 42nd Annual Conference on Information Sciences and Systems ◽

10.1109/ciss.2008.4558606 ◽

2008 ◽

Author(s):

Marco Levorato ◽

Michele Zorzi

Keyword(s):

Ad Hoc Networks ◽

Multiuser Detection ◽

Rate Control ◽

Error Control ◽

Ad Hoc ◽

Control Schemes ◽

Hoc Networks

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Estimation of Modelling Parameters for H.263-Quantized Video Traces

Journal of Computer Networks and Communications ◽

10.1155/2013/351435 ◽

2013 ◽

Vol 2013 ◽

pp. 1-13

Author(s):

A. Drigas ◽

S. Kouremenos

Keyword(s):

Decay Rate ◽

Approximate Method ◽

Rate Control ◽

Shape Parameter ◽

Video Traffic ◽

Quantization Step ◽

Control Schemes ◽

Rate Controlled ◽

Video Traces ◽

Two Parameter

We propose methods for selecting the modelling parameters of H.263-quantized video traffic under two different encoding scenarios. For videos encoded with a constant quantization step (unconstrained), we conclude that a two-parameter power relation holds between the exhibited video bit rate and the quantizer value and that the autocorrelation decay rate remains constant for all cases. On the basis of these results, we propose a generic method for estimating the modelling parameters of unconstrained traffic by means of measuring the statistics of the single “raw” video trace. For rate-controlled video (constrained), we propose an approximate method based on the adjustment of the “shape” parameter of the counterpart—with respect to rate—unconstrained video trace. The convergence of the constructed models is assessed viaq-qplots and queuing simulations. On the assumption that the popular MPEG-4 encoders like XVID, DIVX usually employ identical H.263 quantization and rate control schemes, it is expected that the results of this paper also hold for the MPEG-4 part 2 family.

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