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Publications

Publications by CRIIS

2013

A framework for wireless sensor networks management for precision viticulture and agriculture based on IEEE 1451 standard

Authors
Fernandes, MA; Matos, SG; Peres, E; Cunha, CR; Lopez, JA; Ferreira, PJSG; Reis, MJCS; Morais, R;

Publication
COMPUTERS AND ELECTRONICS IN AGRICULTURE

Abstract
Precision viticulture (PV) and precision agriculture (PA) requires the acquisition and processing of a vast collection of data coming typically from large scale and heterogeneous sensor networks. Unfortunately, sensor integration is far from being simple due to the number of incompatible network specifications and platforms. The adoption of a common, standard communication interface would allow the engineer to abstract the relation between the sensor and the network. This would reduce the development efforts and emerge as an important step towards the adoption of "plug-and-play" technology in PA/PV sensor networks. This paper explores this need and introduces a framework for smart data acquisition in PA/PV that relies on the IEEE 1451 family of standards, which addresses the transducer-to-network interoperability issues. The framework includes a ZigBee end device (sMPWiNodeZ),,as an IEEE 1451 WTIM (Wireless Transducer Interface Module), and an IEEE 1451 NCAP (Network Capable Application Processor) that acts as gateway to an information service provider and WSN (Wireless Sensor Network) coordinator. The paper discusses the proposed IEEE 1451 system architecture and its benefits in PA/PV and closes with results/lessons learned from in-field trials towards smarter WSN.

2013

FouSE: An Android Tool to Help in the Teaching of Fourier Series Expansions in Undergraduate Education

Authors
Reis, MJCS; Soares, S; Cardeal, S; Morais, R; Peres, E; Ferreira, PJSG;

Publication
CSEDU 2013 - Proceedings of the 5th International Conference on Computer Supported Education, Aachen, Germany, 6-8 May, 2013

Abstract
This paper presents an Android application to help in the teaching of Fourier series expansions in undergraduate Electrical Engineering. Consequently, it discusses the teaching of Fourier series concepts in connection with undergraduate Electrical Engineering education; some of the basic Fourier series theory is briefly reviewed. The presented Android application has been found useful in this context. As expected, the application has an easy-to-use, friendly interface, and can be viewed as a tool to help undergraduate students test and assess the Fourier series expansions on a typical set of signals, whose analytical Fourier series coefficients were found during the theoretical lectures. Additionally, some of its main characteristics include the ability for the students to control the total approximation error and the number of terms/harmonics used in the expansion.

2013

Teaching of Fourier Series Expansions in undergraduate education

Authors
Reis, MJCS; Soares, S; Cardeal, S; Morais, R; Peres, E; Ferreira, PJSG;

Publication
2013 IEEE GLOBAL ENGINEERING EDUCATION CONFERENCE (EDUCON)

Abstract
Here we discuss the teaching of Fourier series concepts in connection with undergraduate Electrical Engineering education. We briefly review some of the basic Fourier series theory, and present an Android application that has been found useful in this context. As expected, the application has an easy-to-use, friendly interface, and can be viewed as a tool to help undergraduate students test and assess the Fourier series expansions on a typical set of signals, whose analytical Fourier series coefficients were found during the theoretical lectures. Additionally, students can also control the total approximation error and the number of terms/harmonics used in the expansion. It seems that our students prefer this Android application to the traditional applet fashioned web-based applications.

2013

Effects of elevated temperature and atmospheric carbon dioxide concentration on the emissions of methane and nitrous oxide from Portuguese flooded rice fields

Authors
Pereira, J; Figueiredo, N; Goufo, P; Carneiro, J; Morais, R; Carranca, C; Coutinho, J; Trindade, H;

Publication
ATMOSPHERIC ENVIRONMENT

Abstract
Methane (CH4) and nitrous oxide (N2O) emissions from flooded rice fields have been rarely measured in Europe. A field study was carried out in an intermittent flooded rice field at central Portugal to investigate if global warming under Mediterranean conditions, elevated soil temperature (+2 degrees C) and atmospheric [CO2] (550 ppm), could lead to significant effects in CH4 and N2O emissions. The experimental design consisted of three treatments arranged in a randomized complete block design with three replicates. To assess the effects of ambient temperature and actual atmospheric [CO2] (375 ppm), plots were laid under open-field rice conditions. Using open-top chambers, two other treatments were established: one to assess the effect of elevated temperature and actual atmospheric [CO2] and a third treatment to evaluate the combined effect of elevated temperature and atmospheric [CO2]. Measurements of CH4 and N2O fluxes were made throughout two consecutive growing seasons in the field using the closed chamber technique. Elevation of temperature with or without elevated atmospheric [CO2] increased CH4 emissions by 50%, but this increase was not significant compared to the open-field condition. As for N2O, elevated temperature alone or combined with elevated atmospheric [CO2] had no significant effect on emissions relative to the open-field treatment. The estimated seasonal CH4 EF for the Portuguese flooded rice fields was 10.0 g CH4 m(-2), while the EF for N2O emissions was 1.4% of N input. These results suggested that default seasonal CH4 and N2O EFs currently used by the Portuguese inventory were not appropriated.

2013

Multi-source Harvesting Systems for Electric Energy Generation on Smart Hip Prostheses

Authors
dos Santos, MPS; Ferreira, JAF; Ramos, A; Pascoal, R; dos Santos, RM; Silva, NM; Simoes, JAO; Reis, MJCS; Festas, A; Santos, PM;

Publication
Communications in Computer and Information Science

Abstract
The development of smart orthopaedic implants is being considered as an effective solution to ensure their everlasting life span. The availability of electric power to supply active mechanisms of smart prostheses has remained a critical problem. This paper reports the first implementation of a new concept of energy harvesting systems applied to hip prostheses: the multi-source generation of electric energy. The reliability of the power supply mechanisms is strongly increased with the application of this new concept. Three vibration-based harvesters, operating in true parallel to harvest energy during human gait, were implemented on a Metabloc TM hip prosthesis to validate the concept. They were designed to use the angular movements on the flexion-extension, abduction-adduction and inward-outward rotation axes, over the femoral component, to generate electric power. The performance of each generator was tested for different amplitudes and frequencies of operation. Electric power up to 55 µJ/s was harvested. The overall function of smart hip prostheses can remain performing even if two of the generators get damaged. Furthermore, they are safe and autonomous throughout the life span of the implant. © Springer-Verlag Berlin Heidelberg 2013.

2013

Instrumented hip implants: Electric supply systems

Authors
Soares dos Santos, MPS; Ferreira, JAF; Ramos, A; Simoes, JAO; Morais, R; Silva, NM; Santos, PM; Reis, MJCS; Oliveira, T;

Publication
JOURNAL OF BIOMECHANICS

Abstract
Instrumented hip implants were proposed as a method to monitor and predict the biomechanical and thermal environment surrounding such implants. Nowadays, they are being developed as active implants with the ability to prevent failures by loosening. The generation of electric energy to power active mechanisms of instrumented hip implants remains a question. Instrumented implants cannot be implemented without effective electric power systems. This paper surveys the power supply systems of seventeen implant architectures already implanted in-vivo, namely from instrumented hip joint replacements and instrumented fracture stabilizers. Only inductive power links and batteries were used in-vivo to power the implants. The energy harvesting systems, which were already designed to power instrumented hip implants, were also analyzed focusing their potential to overcome the disadvantages of both inductive-based and battery-based power supply systems. From comparative and critical analyses of the methods to power instrumented implants, one can conclude that: inductive powering and batteries constrain the full operation of instrumented implants; motion-driven electromagnetic energy harvesting is a promising method to power instrumented passive and active hip implants.

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