Rui Esteves Araujo

Abstract
This paper presents steganography techniques that were employed to avoid human perception of the added audio signals in an acoustic environment for indoor location purposes. In the context of audio forensics, indoor location can be used in connection with the detection of a crime. The validation of using the acoustic channel for data transmission over an almost imperceptible audio signal enables the possibility of a receiving processing mobile device (such as a smartphone) to localize itself absolutely by receiving and processing such signals from the infrastructure. Some possible applications will be presented demonstrating the utility of this technology. This paper will present the use of almost imperceptible audio signals to successfully transmit hidden information using a spread spectrum data-hiding technique or a music/speech cover signal and the echo hiding technique.

Abstract
This paper presents a high precision speed control of the reluctance machine for electric drive applications. To get high resolution speed control, it is developed a cascade control algorithm based on linear control technique. The controller was designed using the Root Locus Methodology and has been implemented on a numerical simulation platform. It is shown that Root Locus Methodology design is a viable approach, and that various problems associated with the structural torque ripple of the electric motor can be solved. An important aspect of this work is the role played by model linearization in testing the sensitivity of the controller performance to specific parameter changes. The controller was implemented in a simulated non-linear switched reluctance motor model in order to evaluate their performances. Simulations results show that the high-performance control for Switched Reluctance Motor has been achieved.

Abstract
In a design of a switched reluctance machine, there are a number of parameters that are chosen empirically inside a certain interval, therefore to find an optimum geometry it is necessary to determine how each parameter acts on the performance of the machine. This work presents a study on the influence of geometric dimensions on the performance of the switched reluctance machine. The analysis is done through finite element simulations based on the variation of one parameter while the others are fixed. Graphical and numerical results of torque and magnetic flux are presented for a 6/4 three-phase machine and an 8/6 four-phase machine. The study presented aims to provide consistent data on which dimensions should be modified for specific applications, and thus to base choices made in the design and optimization stage.. © 2019 by the authors.

Abstract
Performance of series connected batteries is limited by the 'weakest link' effect, i.e., the cell or group of cells with the poorest performance in terms of temperature, power, or energy characteristics. To mitigate the 'weakest link' effect, this study deals with the design, modeling, and experimental demonstration of a smart and hybrid balancing system (SHBS). A cell-to-cell shared energy transfer configuration is proposed, including a supercapacitor bank in the balancing bus, thus enabling hybridization. Energy is transferred from each battery module connected in series to the balancing bus, and vice-versa, by means of low-cost bi-directional dc-dc converters. The current setpoints of the converters are obtained by means of a smart balancing control strategy, implemented using convex optimization. The strategy is called 'smart' because it pursues goals beyond the conventional state-of-charge equalization, including temperature and power capability equalization, and minimization of energy losses. Simulations show that the proposed SHBS is able to achieve all these goals effectively in an e-mobility application and are also used to assess the impact of different hybridization ratios and cooling conditions. Finally, an experimental setup is developed to demonstrate the feasibility of the SHBS. © 1967-2012 IEEE.

Abstract