2008
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
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
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.
2008
Authors
Sousa, A; Morais, J; Filipe, V; Jesus, A; Vaz, MAP;
Publication
COMPUTATIONAL VISION AND MEDICAL IMAGING PROCESSING
Abstract
This paper presents a fast and straightforward method to assess displacement fields on the surface of a planar specimen with sub-pixel resolution. First, pixel level displacements are obtained by cross correlation (CC) of two consecutive images, used as the image similarity measure. Next, sub-pixel displacement information is calculated from the CC coefficients matrix using a similarity interpolation method. Finally, sub-pixel estimation error cancellation is performed. Several experiments were conducted to validate the proposed method effectiveness, applied to chestnuts compression test for quality control purposes.
2008
Authors
de Sousa, M;
Publication
2008 IEEE INTERNATIONAL CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION, PROCEEDINGS
Abstract
When developing applications with high integrity requirements, the choice of programming language is of utmost importance. In fact, IEC 61508 includes a table with suggested programming languages for each SIL (Safety Integrity Level). The languages defined in IEC 61131-3 are included in this table, but are only highly recommended for the higher SILs if a subset of the languages are used. In this paper we propose restrictions and changes to the IEC 61131-3 languages that constitute a subset of the languages with the objective of making them appropriate for the development of high integrity applications.
2008
Authors
Santos, AA; de Sousa, M;
Publication
2008 IEEE INTERNATIONAL CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION, PROCEEDINGS
Abstract
The IEC 61499 standard defines function blocks with which distributed control applications may be developed, and how these are interpreted and executed. With the distributed nature of the control application, many issues also need to be taken into account. In this paper we propose a replication management framework for IEC 61499 applications, and discuss some mechanisms and protocols that may be used for this purpose.
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