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Electroencephalographic signals are employed to analyze brain activity. By being low voltage level signals, its digitalization represents a big challenge. Currently, there are several proposals and BCIs, many of them based on complicated and expensive ADCs and DSPs to collect and digitally process data. Hence, this paper presents the design and implementation of an active-filtering circuit for electroencephalographic signal acquisition in a frequency range between 0.15 Hz and 50Hz using an 8-bit AVR RISC-based microcontroller. This hardware is composed of four fundamental elements: Reception block, filtering circuit, ADC adaptation circuit, and digital communication system. This paper offers the results of board design, emulation, and implementation concerning the amplitude spectrum and its SNR value.

Nowadays, high voltage direct current transmission systems are being selected over the traditional alternating current transmission for very long transmission distances. However, there are still some unresolved challenges, most of them in terms of protection of the system. If using traditional protection systems used in alternating current grids, the characteristics of a DC fault make it complicated to clear and dangerous to power electronic components. Hence, there is a need of very fast fault detection and clearance. This paper proposes a full-selective protection system based on a rate of change of voltage. The process of selection of the threshold needed to discriminate fault conditions is described. In addition, the performance of the protection algorithm is analysed. The influence of parameters such as the fault location and fault resistance is evaluated. A comparison with similar algorithms found on the literature is presented at the end.

Local measurement based algorithms are mostly used for fault detection in HVDC systems since communication based algorithms are limited by the communication time delay and, therefore, they are not appropriate for long transmission distances. This paper proposes a local measurement based protection system for multi-terminal HVDC systems. Primary protection is based on rate of change of voltage (ROCOV) algorithm, while the backup and busbar protections are based on rate of change of current (ROCOC) algorithm. The performance of these algorithms is tested through simulation in PSCAD software. The proposed system is validated with different fault case scenarios, including low and high resistance fault conditions. The ROCOV algorithm provides the protection system of a fast, reliable and accurate primary protection against low and high resistance fault conditions. Meanwhile, the ROCOC algorithm is implemented in order to operate in case of primary protection failure. Its operation against low resistance faults is similar to the ROCOV performance, however, it presents low sensitivity to high resistance fault conditions. An overcurrent feature is implemented in order to improve the backup protection sensitivity and reliability. On the other hand, the busbar protection performance is fast, accurate and selective; it does not misdetect link faults.

From a prospect where High Voltage Direct Current systems are the most promising alternative for new grid expansion as well as for integration of renewable energies at worldwide level, this paper analyses DC protection systems and their challenges on detecting and clearing faults. The focus of this paper is a comparison between non-unit and unit protection systems. It is also presented a study case with a simple non-unit algorithm, which is enhanced with a communication system.

A Damper winding performs an important function of protecting the Synchronous Motors (SMs) during transient operations. They also happen to be one source of concern for failure of SMs, which are otherwise quite reliable. The situation aggravates when the motors are fed by variable frequency drives, which brings additional stress on the damper bars. This paper presents theoretical simulations of a salient pole SM with twelve poles, containing three damper bars in each pole, during healthy as well faulty damper bar conditions. The current distribution is calculated in each damper bar. Experiments were conducted on the same SM and the current in the damper bars as well inter-connecting poles were measured and captured on a rotating wireless communication platform, both during healthy and faulty conditions of the damper bars with varying severity. The fault indicators are presented to detect damper bar failure conditions, thereby helping preventive maintenance of SMs.

This document presents the design and implementation of a platform that detects the ON/OFF state of any electronic device and show this information through an Internet web site despite the absence of any Internet network. The device state is defined through a current sensor, the information is saved with date in a backup memory, and then, a Short Message Service (SMS) message containing the ON/OFF state is sent to a massive message platform on the Internet. After that, the information is collected in a custom web platform where the user can access through the Internet and see the electrical status of the device. Additionally, the platform works even when there is not AC power supply.

In this paper the tracking of collision-free path obtained by using Homotopic Path Planning Method (HPPM) with automatic value assignation of repulsion parameter is presented. This work is center on show the utility of this method to obtain a collision free path for maps with narrow corridors on indoor environments. First, the basis of homotopic path planning method with automatic value assignation of repulsion parameter are explained. Second, the Pure-Pursuit controller is brief explained. Third, the capability of the HPPM is shown by using two experiments that which contain narrow passages and several circular obstacles. Finally, in order to validate the solution paths, a tracking on Robot Operating System by using 3P-DX robot model and on MATLAB using a Pure-Pursuit controller from the Robotics Toolbox is performed.

This paper investigates the performance of different power electronic interfaces for a rotating brushless permanent magnet exciter, designed for a synchronous generator test setup. A passive rotating diode bridge is commonly used as the rotating interface on conventional brushless excitation systems. Those systems are known to be slow dynamically, since they cannot control the generator field voltage directly. Including active switching components on the rotating shaft, like thyristors or transistors, brushless excitation systems can be comparable to static excitation systems. Brushless excitation systems has the benefit of less regular maintenance. With permanent magnets on the stator of the designed exciter, the excitation system improves its field forcing capability. Results show that modern power electronic interfaces utilize the exciter machine optimally, increase the power factor, reduce the torque pulsations, maintain the available field winding ceiling voltage and improve the field winding controllability.

This paper deals with the characterization and construction of a rotating brushless PM exciter intended for synchronous generator excitation purposes. Traditionally, PM exciters are used as pre-exciters in synchronous generator excitations systems. In order to reduce the number of components and to increase the step time response of the system, a PM exciter is designed as an outer pole PM machine, with permanent magnets on the stator and armature windings on the rotor. The exciter was constructed electrically and mechanically to be fitted into an in-house synchronous generator test setup. A finite element model of the exciter was validated with no-load measurements of voltages and magnetic flux densities. The exciter was then characterized with unsaturated and saturated parameters.

The planning of courses of action for a task force component requires the evaluation of the available options and their respective impact to the operational goals. This includes considering the rules of engagement (ROE), i.e. the directives that define the circumstances and conditions in which force, or actions, which might be construed as provocative, may be applied. These rules vary across nations and are usually presented in manuals that require interpretation, requiring an often-complex decision process. In this paper, the problem of refining the decisions on a course of action based on the automated execution of rules of engagement is approached. An ontology representing the rules and a generic situation scenario is described, and the approach is evaluated by the encoding of the San Remo set of rules of engagement.

The principal aim was the construction of a face recognition system in order to be implemented in the service robot "Donaxi", delimited by the "Who is who" test which is part of the RoboCup's tests set, using an evolutionary development strategy of triple iterations. A two phase hybrid algorithm was developed, the first phase aim was the face detection using the Haar classifiers for face search in an image and the second phase is based on a decision tree whereby the faces characteristics were evaluated by the comparison techniques of phase correlation and histogram comparison. The needed characteristics were identified in order to develop this work as a software engineering project which allowed the algorithm construction and implementation through an evolutionary approach and a personal development process. The evolutionary strategy allowed the prototyping development with functionality and the tracking of the final system construction. A three iterations total was realized during which the needed metrics were registered (time, defects and sizes). The final analysis of results (algorithm and methods) allowed concluding and visualizing the employment advantages of a software engineering formal technique for research and robotics projects realization when improving estimations and software production quality.

Pattern Recognition (PR) tasks are natural candidatesfor embedded systems, since they usually interact with humans and other complex processes in the real world. Often regarded as the part of Artificial Intelligence (AI) closer to perception, a typical PR application reacts to external events that the system perceives through physical sensors or input devices and produces a response using actuators or information display subsystems. Being usually far from trivial, very demanding from the computational point of view, and requiring a fast reaction time, PR algorithms constitute a real challenge to the embedded system designer. In this talk, some of the main application domains and optimization approaches proposed to deal with these relevant issues, along with many open problems and paths to improvement, are presented.