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Publications

Publications by CRIIS

2008

A robotic soccer passing task using Petri net plans

Authors
Palamara, PF; Nardi, D; Ziparo, VA; Lima, P; Iocchi, L; Costelha, H;

Publication
Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS

Abstract

2008

Automated Synthesis Procedure of RF Discrete Tuning Differential Capacitance Circuits

Authors
Mendes, L; Solteiro Pires, EJS; Vaz, JC; Rosario, MJ; de Moura Oliveira, PBD; Tenreiro Machado, JAT; Fonseca Ferreira, NMF;

Publication
APMC: 2008 ASIA PACIFIC MICROWAVE CONFERENCE (APMC 2008), VOLS 1-5

Abstract

2008

Single-objective front optimization: application to rf circuit design

Authors
Pires, EJS; Machado, JAT; Mendes, L; Ferreira, NMF; De Moura Oliveira, PB; Vaz, J; Rosario, M;

Publication
Genetic and Evolutionary Computation Conference, GECCO 2008, Proceedings, Atlanta, GA, USA, July 12-16, 2008

Abstract
This paper proposes a new algorithm which promotes well distributed non-dominated fronts in the parameters space when a single-objective function is optimized. This algorithm is based on e-dominance concept and maxmin sorting scheme. Besides that, the paper also presents the results of the algorithm when it is used in the automated synthesis of optimum performance CMOS radio-frequency and microwave binary-weighted differential switched capacitor arrays (RFDSCAs). The genetic synthesis tool optimizes a fitness function which is based on the performance parameter of the RFDSCAs. To validate the proposed design methodology, a CMOS RFDSCA is synthesized, using a 0.25 µm BiCMOS technology.

2008

An embedded system to assess the automotive shock absorber condition under vehicle operation

Authors
Ventura, PJC; Ferreira, CDH; Neves, CFCS; Morais, RMP; Valente, ALG; Reis, MJCS;

Publication
Proceedings of IEEE Sensors

Abstract
The automotive suspension plays a crucial role in vehicle safety and driving comfort. One of the most important components in vehicle suspensions is the damper (or shock absorber). Because there is no precise method to perform shock absorber test within the vehicle, an embedded autonomous system, powered by the energy harvested from the shock absorber itself, capable of monitoring shock absorber parameters and transmitting these values throughout a wireless interface to the vehicle central diagnostic unit, is presented. Such a device will permit the shock absorber condition assessment under vehicle operation, which to our best knowledge is considered a breakthrough in vehicle safety. © 2008 IEEE.

2008

Sun, wind and water flow as energy supply for small stationary data acquisition platforms

Authors
Morais, R; Matos, SG; Fernandes, MA; Valente, ALG; Soares, SFSP; Ferreira, PJSG; Reis, MJCS;

Publication
COMPUTERS AND ELECTRONICS IN AGRICULTURE

Abstract
The deployment of large mesh-type wireless networks is a challenge due to the multitude of arising issues. Perpetual operation of a network node is undoubtedly one of the major goals of any energy-aware protocol or power-efficient hardware platform. Energy harvesting has emerged as the natural way to keep small stationary hardware platforms running, even when operating continuously as network routing devices. This paper analyses solar radiation, wind and water flow as feasible energy sources that can be explored to meet the energy needs of a wireless sensor network router within the context of precision agriculture, and presents a multi-powered platform solution for wireless devices. Experimental results prove that our prototype, the MPWiNodeX, can manage simultaneously the three energy sources for charging a NiMH battery pack, resulting in an almost perpetual operation of the evaluated ZigBee network router. in addition to this, the energy scavenging techniques double up as sensors, yielding data on the amount of solar radiation, water flow and wind speed, a capability that avoids the use of specific sensors.

2008

Fractional electrical impedances in botanical elements

Authors
Jesus, IS; Machado, JAT; Cunha, JB;

Publication
JOURNAL OF VIBRATION AND CONTROL

Abstract
Fractional calculus (FC) is no longer considered solely from a mathematical viewpoint, and is now applied in many emerging scientific areas, such as electricity, magnetism, mechanics, fluid dynamics, and medicine. In the field of dynamical systems, significant work has been carried out proving the importance of fractional order mathematical models. This article studies the electrical impedance of vegetables and fruits from a FC perspective. From this line of thought, several experiments are developed for measuring the impedance of botanical elements. The results are analyzed using Bode and polar diagrams, which lead to electrical circuit models revealing fractional-order behaviour.

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