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Publications

Publications by António Valente

2015

Grigora S: A Low-Cost, High Performance Micromouse Kit

Authors
Valente, A; Salgado, P; Boaventura Cunha, J;

Publication
CONTROLO'2014 - PROCEEDINGS OF THE 11TH PORTUGUESE CONFERENCE ON AUTOMATIC CONTROL

Abstract
There is a need to attract students to science and engineering courses. Robotic contests are one of the most promising ways to attract students to the field of robotics and thereby to science and technology. Micromouse contest is one of promising contests where a small autonomous robot has to navigate its way through an unknown 16 x 16 cells maze. Since the design and construction of robots is interesting but difficult, this paper presents a high performance, low-cost robot kit for high school and university students participate on micromouse robot contests. This micromouse kit, developed at University of Tras-os-Montes and Alto Douro (UTAD), fits on a 10x8 cm rectangle and uses very small stepper motors allowing a maximum speed of about 4 m/s thus comparing to state-of-the-art micromice. The kit also incorporates a popular microcontroller hardware module (Arduino Leonardo) which facilitates all programming tasks.

2015

Message from the chairs

Authors
Valente, A; Morais, R; Marques, L; Almeida, L;

Publication
Proceedings - 2015 IEEE International Conference on Autonomous Robot Systems and Competitions, ICARSC 2015

Abstract

2014

HarmoSim: A tool for harmonic distortion simulation and assessment of nonlinear loads

Authors
Baptista, J; Morais, R; Valente, A; Soares, S; Candeias, M; Reis, MJCS;

Publication
COMPUTER APPLICATIONS IN ENGINEERING EDUCATION

Abstract
Electrical power quality (PQ) is a crucial competitive and developing factor to all economic activities. The economic impact resulting from a bad PQ would be drastic on all consumers. Computers, uninterruptible and switched power supplies (UPS), and fluorescent lamps/tubes are examples of nonlinear loads that have the consumption of a nonsinusoidal current, which cause disturbances in the power supply system (that may be severe or not). This study discusses residential generic power circuitry analysis and simulation, under nonlinear loads, in connection with undergraduate electrical engineering education. It briefly reviews some of the basic techniques, and presents a software tool that has been found to be very useful in the context. The tool has an easy-to-use, friendly interface, and can be used to teach design techniques or as a laboratory support to study the applicability of known methods to real situations. The students can perform simulations with their own data on Microsoft (TM) Windows (R)-based platforms. (c) 2011 Wiley Periodicals, Inc. Comput Appl Eng Educ 22:340-348, 2014; View this article online at ; DOI

2013

Radiation tests on a bluetooth based front-end electronic device towards a subcutaneous continuous glucose monitoring sensor

Authors
Silva, S; Soares, S; Valente, A; Moreira, A;

Publication
Proceedings of 2013 Science and Information Conference, SAI 2013

Abstract
The metabolic disorder which entails the absent or reduced control of blood glucose in the body by means of insulin dependence (Type 1) or intolerance (Type 2) affected more than 366 million people in 2011. This represents an increase of 28% new cases in one year. Diabetes Mellitus has become the most common chronic diseases in nearly all countries, and continues to increase in numbers and significance, as economic development and urbanization lead to changing lifestyles characterized by reduced physical activity, and increased obesity. Recent advances in wireless sensor networking technology have led to the development of low cost, low power, multifunctional sensor nodes that enable environment sensing together with data processing. Instrumented with a variety of sensors, such as temperature, humidity, volatile compound detection, bio implanted sensors; the development of such networks requires testing for transmission distance and human body interference. As Bluetooth Low-Energy (BLE) operates in the free 2.4GHz ISM band, the same band that Wi-Fi signals operate, tests regarding interference, robustness and coexistence must be made in order to ensure Quality of Service (QoS) and therefore achieve medical diagnostic equipment status. This paper presents a BLE prototype and compares the results obtained in terms of radiated power over distance with and without physical barriers. © 2013 The Science and Information Organization.

2014

Coexistence and Interference Tests on a Bluetooth Low Energy Front-End

Authors
Silva, S; Soares, S; Fernandes, T; Valente, A; Moreira, A;

Publication
2014 SCIENCE AND INFORMATION CONFERENCE (SAI)

Abstract
Over the last decade, impelled by the industry demand to achieve a technology capable of sending low amount of data payloads, but at the same time with a very low latency and ultra-low power consumption, several efforts in wireless network transmission standardization emerged, supporting new applications in health, sports and fitness, medical, sensor networking, and even the automotive industry field. Despite the competition from ANT+, ZigBee, Nike+, NFC and RF4CE, in 2010 the Bluetooth SIG (special interest groups) adopted a new wireless technology named Bluetooth Low Energy (BLE). BLE coexist with Bluetooth in the same chip (called dual mode) therefore assuring this technology a rapid growth among smartphones, iOS, tablets, laptops and PCs. In fact, Bluetooth SIG also announced that it shall be hard to find a smartphone or tablet-PC that does not integrate BLE in the near future. Despite this accelerated growth, BLE shares the same band with Wi-Fi and all other low power technologies, so in order to achieve QoS, a mandatory requirement in many systems, tests for interference and coexistence must be performed. This study analysis the impact of a BLE sensor network on a crowded 2.4GHz room, with multiple Wi-Fi routers, ZigBee sensors and Bluetooth technology. We also compare the results with the ones obtained inside an anechoic chamber on similar experiences.

2014

Traffic Sign Recognition for Autonomous Driving Robot

Authors
Moura, T; Valente, A; Sousa, A; Filipe, V;

Publication
2014 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC)

Abstract
This paper introduces a fast Traffic Sign Recognition system developed for a robot, participant in the Autonomous Driving Competition in the Portuguese Festival of Robotics. The Autonomous Driving Robot performs detection and classification of traffic signs and traffic lights based on the analysis of images acquired by a camera mounted on its chassis. The proposed algorithm is composed of three processing stages: detection, pictogram extraction and classification. After the two firsts processing stages, a binary pattern matrix is obtained by color segmentation. In the classification stage two different neural networks were trained to recognize the traffic signs or the traffic light sign. Experimental results show that the system precision is very close to 100% whereas recall presents values above 90% in most of the signs. The proposed system also proves to be reliable and suitable for real-time processing.

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