Model-independent rate control for intra-coding based on piecewise linear approximations

This paper proposes a rate control (RC) algorithm for intra-coded sequences (I-frames) within the context of block-based predictive transform coding that departs from using trained models to approximate the rate-distortion (R-D) characteristics of the video sequence. Our algorithm employs piecewise linear approximations of the rate-distortion (R-D) curve of a frame at the block-level. Specifically, it employs information about the rate and distortion of already compressed blocks within the current frame to linearly approximate the slope of the R-D curve of each block. The proposed algorithm is implemented in the High-Efficiency Video Coding (H.265/HEVC) standard and compared with its current RC algorithm, which is based on a trained model. Evaluations on a variety of intra-coded sequences show that the proposed RC algorithm not only attains the overall target bit rate more accurately than the RC algorithm used by H.265/HEVC algorithm but is also capable of encoding each I-frame at a more constant bit rate according to the overall bit budget

Coarse roll-rate gain-control circuit

Circuit is used in spin-rate computing unit of control system for solar pointing rocket during its acquisition mode. Direction cosines from magnetometers and coarse sun sensors derive function that is approximately roll-rate times sum of absolute value of direction cosines

Familywise Error Rate Control via Knockoffs

We present a novel method for controlling the $k$-familywise error rate ($k$-FWER) in the linear regression setting using the knockoffs framework first introduced by Barber and Cand\`es. Our procedure, which we also refer to as knockoffs, can be applied with any design matrix with at least as many observations as variables, and does not require knowing the noise variance. Unlike other multiple testing procedures which act directly on $p$-values, knockoffs is specifically tailored to linear regression and implicitly accounts for the statistical relationships between hypothesis tests of different coefficients. We prove that knockoffs controls the $k$-FWER exactly in finite samples and show in simulations that it provides superior power to alternative procedures over a range of linear regression problems. We also discuss extensions to controlling other Type I error rates such as the false exceedance rate, and use it to identify candidates for mutations conferring drug-resistance in HIV.Comment: 15 pages, 3 figures. Updated reference

Equilibrium Properties of Rate Control Protocols

We analyze the stability of the Rate Control Protocol (RCP) using two different models that have been proposed in literature. Our objective is to better understand the impact of the protocol parameters and the effect different forms of feedback have on the stability of the network. We also highlight that different time scales, depending on the propagation delay relative to the queuing delay, have an impact on the nonlinear and the stochastic properties of the protocol fluid models. To better understand some of the nonlinear properties, we resort to local bifurcation analysis where we exhibit the existence of a Hopf type bifurcation that then leads to stable limit cycles. Our work serves as a step towards a more comprehensive understanding of the nonlinear fluid models that have been used as representative models for RCP.Comment: 8 pages, 4 figures, submitted to ICITST 201