High-throughput variable-to-fixed entropy codec using selective, stochastic code forests

Efficient high-throughput (HT) compression algorithms are paramount to meet the stringent constraints of present and upcoming data storage, processing, and transmission systems. In particular, latency, bandwidth and energy requirements are critical for those systems. Most HT codecs are designed to maximize compression speed, and secondarily to minimize compressed lengths. On the other hand, decompression speed is often equally or more critical than compression speed, especially in scenarios where decompression is performed multiple times and/or at critical parts of a system. In this work, an algorithm to design variable-to-fixed (VF) codes is proposed that prioritizes decompression speed. Stationary Markov analysis is employed to generate multiple, jointly optimized codes (denoted code forests). Their average compression efficiency is on par with the state of the art in VF codes, e.g., within 1% of Yamamoto et al.\u27s algorithm. The proposed code forest structure enables the implementation of highly efficient codecs, with decompression speeds 3.8 times faster than other state-of-the-art HT entropy codecs with equal or better compression ratios for natural data sources. Compared to these HT codecs, the proposed forests yields similar compression efficiency and speeds

Our own action kinematics predict the perceived affective states of others.

Our movement kinematics provideuseful cues aboutour affective states. Given that our experiences furnish models that help us to interpret our environment, and that a rich source of action experience comes from our own movements,the present study examined whetherwe use models of our own action kinematics to make judgments about the affective states of others. For example,relative to one’s typical kinematics, anger isassociated with fast movements. Therefore, the extent to which we perceive angerin others maybe determined by the degreeto which their movementsare faster than our own typicalmovements. We related participants’walking kinematicsin a neutral contextto their judgments of the affective statesconveyed byobserved point-light walkers(PLWs). Aspredicted,we found a linear relationship between one’s own walking kinematics and affective state judgments, such that faster participants rated sloweremotionsmore intensely relative to their ratings for faster emotions. This relationship was absent when observing PLWs where differences in velocity between affective states were removed. These findings suggest that perception of affective states in others is predicted by one’s own movement kinematics, withimportant implications for perception of, and interaction with,those who move differentl

Building the Big Society

Papers are a contribution to the debate and set out the authors ’ views only Localism and the Big Societ

Design and application of variable-to-variable length codes

This work addresses the design of minimum redundancy variable-to-variable length (V2V) codes and studies their suitability for using them in the probability interval partitioning entropy (PIPE) coding concept as an alternative to binary arithmetic coding. Several properties and new concepts for V2V codes are discussed and a polynomial-based principle for designing V2V codes is proposed. Various minimum redundancy V2V codes are derived and combined with the PIPE coding concept. Their redundancy is compared to the binary arithmetic coder of the video compression standard H.265/HEVC

Transparent code authentication at the processor level

The authors present a lightweight authentication mechanism that verifies the authenticity of code and thereby addresses the virus and malicious code problems at the hardware level eliminating the need for trusted extensions in the operating system. The technique proposed tightly integrates the authentication mechanism into the processor core. The authentication latency is hidden behind the memory access latency, thereby allowing seamless on-the-fly authentication of instructions. In addition, the proposed authentication method supports seamless encryption of code (and static data). Consequently, while providing the software users with assurance for authenticity of programs executing on their hardware, the proposed technique also protects the software manufacturers’ intellectual property through encryption. The performance analysis shows that, under mild assumptions, the presented technique introduces negligible overhead for even moderate cache sizes

A Side-Channel Attack Against the Secret Permutation on an Embedded McEliece Cryptosystem

International audience—In this paper, based on a thorough analysis of the state of the art, we point out a missing solution for embedded devices to secure the syndrome computation. We show that this weakness can open the door to a side-channel attack targeting the secret permutation. Indeed, brute-force attack iterations are dramatically decreased when the secret permutation is recovered. We demonstrate the feasibility of this attack against the McEliece cryptosystem implemented on an ARM Cortex-M3 microprocessor using Goppa codes. We explain how to recover the secret permutation on a toy example. Finally, we propose a promising countermeasure, which can be implemented in embedded devices to prevent this attack