N. Ben Amor

Multi-Granularity Metrics for the Era of Strongly Personalized SOCs

This paper details the first step of the Design Trotter framework for design space exploration applied to dedicated SOCs. The aim of this step is to provide metrics in order to guide the designer and the synthesis tool towards an efficient application architecture matching. This work presents a computation of metrics at all levels of the application graph-based hierarchy. These metrics are computed through data and control dependency analysis. They quantify the memory, control and processing orientations as well as the average of parallelism for different granularities.

Smart Interfaces for Low Power Energy Harvesting Systems

An effective energy management plays a key role in environmental energy harvesting systems due to the low energy densities involved. The energy flow inside an energy management interface should be organized in order to guaranty the operation of the system and minimize energy losses. An efficient interface for low power solar cells is proposed. It combines a current-to-voltage converter with a storage unit, a super-capacitor, optimizing the energy flow from the solar cell to a load. Circuit simulations of the interface agree with experimental results.

Investigation to the Use of Vibration Energy for Supply of Hearing Aids

Using ambient energy, the operation time of batteries in mobile applications can be increased and the acceptability by the user can be improved. In this paper we investigate the possibilities to design hearing aids as power aware system scavenging energy directly from its environment. The energy source we consider is vibration produced by movements primarily in the neighbourhood of the ear and other movements of the human body. Experimental measurements of vibration were evaluated by means of a theoretical model. The results show that an interesting improvement of battery operation time can be reached.

Energy harvesting from human body for biomedical autonomous systems

The aim of this paper is to illustrate the possibility of recovering electrical energy from human body with micro and macro movements. Micro movements are from breath while macro movements are from hands and/or foot. Their combination can represent, in terms of quantity, an interesting availability to supply biomedical autonomous apparatuses and devices. The choice of integrating these kinds of movements will help patients or persons to recover energy, e.g. from breath while they are seated. Consequently, a correct modeling is requested to optimize the energy converter for supplying the biomedical autonomous systems. In human beings, when each breath process is completed, the lung still contains a volume of air, called the functional residual capacity (approximately 2200 mL). The current research shows the usefulness of a correct modeling, hence a correct converter. The paper allows to determine the minimum mechanical energy necessary to get an interesting level of electrical energy.

Magnetic and specific heat studies of the frustrated Er2Mn2O7 compound

Abstract A new Er2Mn2O7 compound was synthesized by the ceramic method and its crystal structure was characterized using powder X-ray diffraction (XRD) and observed by scanning electron microscopy (SEM). The magnetic properties were investigated using a BS2 magnetometer and the heat capacity was studied using a quantum design (PPMS). The structural study revealed that this compound was monophasic and crystallized in the monoclinic system with the P2/M space group. Magnetization measurements were carried out in the temperature range of 1.8-200 K under an applied magnetic field of 0.05 T. A crossover from a room temperature paramagnetic phase to an antiferromagnetic one at low temperature was detected from the magnetic study. The magnetic susceptibility, in the paramagnetic region above 40 K, was found to present a simple Curie-Weiss type behavior. From the specific heat (CP) measurements in magnetic fields up to 5 T, we noted the presence of a wide peak characteristic of a second order magneto-structural transition.