Camera Networks Dimensioning and Scheduling with Quasi Worst-Case Transmission Time

This paper describes a method to compute frame size estimates to be used in quasi Worst-Case Transmission Times (qWCTT) for cameras that transmit frames over IP-based communication networks. The precise determination of qWCTT allows us to model the network access scheduling problem as a multiframe problem and to re-use theoretical results for network scheduling. The paper presents a set of experiments, conducted in an industrial testbed, that validate the qWCTT estimation. We believe that a more precise estimation will lead to savings for network infrastructure and to better network utilization

H.264 Video Frame Size Estimation

This report describes a method to estimate the video bandwidth for IP cameras using the H.264 standard. The precise determination of bandwidth allows us to model the network access as a scheduling problem and/or estimate the amount of data that would traverse it during different periods. The paper is written to be as didactic as possible and presents a set of experiments, conducted in an industrial testbed, that validate the estimation. We believe that a more precise estimation will lead to savings for network infrastructure and to better network utilizatio

A Survey of Schedulability Analysis Techniques for Rate-Dependent Tasks

In automotive embedded real-time systems, such as the engine control unit, there are tasks that are activated whenever the crankshaft arrives at a specific angular position. As a consequence the frequency of activation changes with the crankshaft’s angular speed (i.e., engine rpm). Additionally, execution times and deadlines may also depend on angular speeds and positions. This paper provides a survey on schedulability analysis techniques for tasks with this rate-dependent behaviour. It covers different task-models and analysis methods for both fixed priority and earliest deadline first scheduling. A taxonomy of the different analysis methods, classifying them according to the assumptions made and the precision of the analysis, is provided at the end of the pape

Dynamic Priority Scheduling of Periodic Tasks with Extended Precedences

International audienceThe software architecture of a critical embedded control system generally consists of a set of multi-periodic communicating tasks. In order to be able to describe such a system, we define the notion of \emph{semaphore precedence constraint}, which supports multi-rate communications that follow regular repetitive patterns. We propose a feasibility test for EDF and we study three implementations, for periodic task sets related by such extended precedences on monoprocessor architectures

Scheduling analysis of fixed priority hard real-time systems with multiframe tasks

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Smart real time operating system

Ph.DDOCTOR OF PHILOSOPH