2013
Authors
Pereira, P; Leitao, S; Solteiro Pires, EJS;
Publication
2013 1ST BRICS COUNTRIES CONGRESS ON COMPUTATIONAL INTELLIGENCE AND 11TH BRAZILIAN CONGRESS ON COMPUTATIONAL INTELLIGENCE (BRICS-CCI & CBIC)
Abstract
This paper makes a study about optimal supply of the energy service, using simulations of network operation scenarios, in order to optimize resources and minimize the variables: operation cost, energy losses, generation cost and consumers shedding. These simulations create optimal operation models of the network, allowing the system operator obtain knowledge to take pre-established procedures that must be performed in situations of contingency in order to forecast and minimize drawbacks. The simulations were performed using a multiobjective particle swarm optimization algorithm. The algorithm was applied to the IEEE 14 Bus network where the optimal power flow was evaluated by MATPOWER tool to establish an optimal electrical working model to minimize the associated costs.
2013
Authors
Pires, EJS; Mendes, L; Lopes, AM; de Moura Oliveira, PB; Machado, JAT;
Publication
Intelligent Systems, Control and Automation: Science and Engineering
Abstract
This paper addresses the problem of finding several different solutions with the same optimum performance in single objective real-world engineering problems. In this paper a parallel robot design is proposed. Thereby, this paper presents a genetic algorithm to optimize uni-objective problems with an infinite number of optimal solutions. The algorithm uses the maximin concept and e-dominance to promote diversity over the admissible space. The performance of the proposed algorithm is analyzed with three well-known test functions and a function obtained from practical real-world engineering optimization problems. A spreading analysis is performed showing that the solutions drawn by the algorithm are well dispersed. © 2013, Springer Science+Business Media Dordrecht.
2013
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
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
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
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.
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