Keyframe insertion : enabling low-latency random access and packet loss repair

From a video coding perspective, there are two challenges when performing live video distribution over error-prone networks, such as wireless networks: random access and packet loss repair. There is a scarceness of solutions that do not impact steady-state usage and users with reliable connections. The proposed solution minimizes this impact by complementing a compression-efficient video stream with a companion stream solely consisting of keyframes. Although the core idea is not new, this paper is the first work to provide restrictions and modifications necessary to make this idea work using the High-Efficiency Video Coding (H.265/HEVC) compression standard. Additionally, through thorough quantification, insight is provided on how to provide low-latency fast channel switching capabilities and error recovery at low quality impact, i.e., less than 0.94 average Video Multimethod Assessment Fusion (VMAF) score decrease. Finally, worst-case drift artifacts are described and visualized such that the reader gets an overall picture of using the keyframe insertion technique

A Scalable Implementation of Fault Tolerance for Massively Parallel Systems

For massively parallel systems, the probability of cr s~Yslenc failure clue to u random hardware fault becomes statistically very significant because of the huge number of components. Besides, filult injection experiments show that multiple failures go undetected, leading to incorrect results. Hence, massively parallel systems reguirc abilities to tolerate: these faults that will occur. The FTMPS project presents a scalable implementation to integrate the different steps to,laull tolerance into existing HPC systems . On the initial parallel .system only 4017v of (randomly injected),faulls do not cause the application to crash or produce wrong results . 1n. the resulting FTMPS prototype more than. 80%, of these ftiults are correctly detected and recovered. Resulting overhead for the application is only between 10 and 20%. Evaluation. of the different, co-operating fault tolerance modules shows the,llexibility and the ,.scalability of the approach.This project is partly sponsored by ESPRIT project 6731 (FTMPS): "Fault Tolerance in Massively Parallel Systems" . Geert Deconinck and Johan Vounckx have a grant from the Flemish Institute for the Advancement of Scientific and Technological Research in Industry (IWT). Rudy Lauwereins is a Senior Research Associate of the Belgian Fund for Scientific Research

Integration, the VLSI Journal

International audienc

The Consistent File-Status in a User-Triggered Checkpointing Approach

The user-triggered checkpointing tool implements a non-blocking, co-ordinated (global) checkpointing method, where the programmer defines the contents and the position of the recovery-line. Within this tool, we developed and implemented file-checkpointing. This allows to include the status of files into the checkpoints and to restore this status when the application is rolled back. The file-status in the checkpoint-data is limited to those attributes of the files that are strictly needed to guarantee consistency. The developed approach is suited for files that are accessed by a single process or shared by several processes and are accessed for reading and/or for writing. Consistency is guaranteed under the fail-silent as well as under the fail-time-bounded fault-models. The programmer-involvement is compensated by the smaller time-overhead. Keywords file-checkpointing, fault-tolerance, checkpointing and rollback, backward error recovery 1. Introduction Several families of techniques..

Passive Frequency Selective Surface Array as a Diffuser for Destroying Millimeter Wave Coherence

This paper presents the design, construction, and testing of grounded frequency selective surface (FSS) array as a diffuser for destroying millimeter wave coherence which is used to eliminate speckle in active millimeter wave imaging. To create stochastically independent illumination patterns, we proposed a diffuser based on random-phase distributions obtained by changing the incident frequency. The random-phase diffuser was obtained by mixing up the phase relations between the cells of a deterministic function (e.g., beam splitter). The slot length of FSS is the main design parameter used to optimize the phase shifting properties of the array. The critical parameters of the diffuser array design, such as phase relation with slot lengths, losses, and bandwidth, are discussed. We designed the FSS arrays with finite integral technique (FIT), fabricated by etching technique, and characterized the S-parameters with a free-space MVNA, and measured the radiation patterns with a BWO in motorized setup

Ontwerp van een snel en hoog performant systeeem voor SMD identificatie

SIGLEKULeuven Campusbibliotheek Exacte Wetenschappen / UCL - Université Catholique de LouvainBEBelgiu