ESAE 2015 Abstracts

Full Papers
Paper Nr: 1

A Real-Time Feedback Scheduler based on Control Error for Environmental Energy Harvesting Systems


Akli Abbas, Emmanuel Grolleau, Malik Loudini and Walid-Khaled Hidouci

Abstract: This paper addresses a real-time scheduling problem inherent to energy harvesting real-time systems. Traditionally, the energy saving problem is solved mainly by taking into account the tasks scheduling parameters such as worst-case execution time and period. In this work, we construct a feedback control scheduling scheme in which a discrete processor speed is assigned according to the control error and available energy. The real-time control tasks would get high processor speeds when their control errors increase. The experimental evaluation of this solution verifies that the feedback scheduling system based on control error gives a good compromise between available energy and systems performance.

Paper Nr: 2

Overhead Considerations in Real-time Energy Harvesting Systems


Hussein El Ghor and Maryline Chetto

Abstract: The effectiveness of a real-time scheduling algorithm depends on both its ability to schedule feasible task sets and its runtime overhead. In this paper, we investigate overheads incurred by a scheduler dedicated to embedded systems that are powered by renewable energy. We specifically focus on the overhead cost of an EDF-based scheduler known as ED-H. We analyze the number of tasks factor that can possibly affect the resulting performance of ED-H. The simulation experiments demonstrate that the implementation costs of ED-H remain acceptable so as to make it a practicable scheduler.

Paper Nr: 3

Modeling, Analysis and Design of a Closed-loop Power Regulation System for Multimedia Embedded Devices


Qiong Tang, Ángel M. Groba, Eduardo Juárez and César Sanz

Abstract: In this paper, the plant modeling as well as the theoretical analysis and design and simulation of a closed-loop control system for the power consumption of a hand-held multimedia embedded device are presented. This is a first validation step for a target system in which the power consumption will be regulated based on estimation feedback. Prior to the availability of power estimation data, actual power consumption measurements are used to obtain a mathematical model of the controlled plant. Then, classic control-theory methods are applied to get a closed-loop integral controller able to regulate the power consumption of a video decoder running in an embedded development platform. The simulation results show how the system output keeps track of the set point without average steady-state error, even in the presence of consumption fluctuations, thus announcing promising results for the closed-loop approach to the final power regulation system.