The uncertainty associated with the increasingly wind power penetration in power systems must be considered when performing the traditional day-ahead scheduling of conventional thermal units. This uncertainty can be represented through a set of representative wind power scenarios that take into account the time-dependency between forecasting errors. To create robust Unit Commitment (UC) schedules, it is widely seen that all possible wind power scenarios must be used. However, using all realizations of wind power might be a poor approach and important savings in computational effort can be achieved if only the most representative subset is used. In this paper, the new hybrid metaheuristic DEEPSO and clustering techniques are used in the traditional stochastic formulation of the UC problem to investigate the robustness of the UC schedules with increasing number of wind power scenarios. For this purpose, expected values for operational costs, wind spill, and load curtailment for the UC solutions are compared for a didactic 10 generator test system. The obtained results shown that it is possible to reduce the computation burden of the stochastic UC by using a small set of representative wind power scenarios previously selected from a high number of scenarios covering the entire probability distribution function of the forecasting uncertainty.

a b s t r a c tThis paper addresses the problem of decision making in Unit Commitment in systems with a significant penetration of wind power. Traditional approaches to Unit Commitment are inadequate to fully deal with the uncertainties associated to wind, represented by scenarios of forecasted wind power qualified by probabilities. Departing from a critique of planning paradigms, the paper argues that a stochastic programming approach, while a step in the good direction, is insufficient to model all aspects of the decision process and therefore proposes the adoption of models based on a Risk Analysis paradigm. A case study is worked out reinforcing this perspective. In a multi-objective context, the properties of the cost vs. risk Pareto-optimal fronts are analyzed, where risk may be represented by aversion to a worst scenario or a worst event. It is shown that the Pareto-optimal front may not be convex, which precludes a simplistic use of tradeoff concepts. It is also shown that decisions based on stochastic programming may in fact put the system at risk. An evaluation of risk levels and cost of hedging against undesired events is proposed as the paradigm to be followed in Unit Commitment decision making.

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A flower-shape bio-inspired aperture-coupled antenna array for on-chip application, generated by Gielis formula, operating in industrial, scientific and medical (ISM) band at 60 GHz (57 GHZ to 64 GHz) is presented in this paper. The antenna proposed is composed of a transmission feed line followed by an aperture and patch element built in aluminum, with 2 micrometers of thickness, lying on two layers of silicon with 200 micrometers of thickness each. Dimensions of the antennas were calculated according to the effective wavelength for the resonance frequency at 60 GHz. Simulations were performed in the commercial software ANSYS® Electronics Desktop. The use of the bio-inspired flower-shape promotes more compact structures with greater perimeter, rearranging these shapes into an antenna array provided a gain and a bandwidth increase in the design, 3.11dBi and 2.86GHz, respectively, which resulted in a maximum gain of 8.82 dBi and a total bandwidth of 5.88 GHz.

This paper presents the characterization of dielectric properties (dielectric permittivity and dielectric loss factor) of Tommy Atkins mango (Mangifera indica L), a fruit produced in several regions of Brazil, of great economic importance. The fruits were characterized according to their maturation index, by probe method, and identified by the yellowish tone in their bark. The results allowed correlating the dielectric characteristics of the fruit with the physicochemical transformations that occurred in the maturation process of the mango Tommy. It was also verified a greater variation in the frequencies below 1 GHz, with the maturation indicated by the dielectric signature on the fifth day after the harvest. From these results, we can observe the use of electromagnetic materials and techniques in the solution and optimization of processes in agriculture can improve the quality of products consumed or suggesting best practices to the productive sector.

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In this work, it is proposed the development a new monopole directional antenna, bioinspired in elliptical leaf, with cut by golden ratio, for 4G band application, by the use of the technique of the cut of the radiating element for the increasing of the antenna perimeter, being the first work to use this technique in a bioinspired antenna, promotes resonance frequency turned, and reconfiguring of the antenna parameters as bandwidth, radiation pattern and gain, with the use of the reflector near to the group plane, without the insertion of active devices as the pin diode or change in radiating element. The shape antenna is generated by Gielis formula, built in FR4 substrate, with cuts calculated by golden ratio. To compare the results of the bioinspired monopole on the elliptical sheet, a square-shaped monopole antenna was designed, simulated and measured, the structures were designed in the MATLAB software version 2015(b) and the simulations were performed in the Ansys software version 2016. In the results compared between the square monopole and the bioinspired antenna in the elliptical sheet, it can be seen that the measured bioinspired antenna, compared to the square monopole, presented a bandwidth reduction of 77.27%, a more compact structure, with a reduction of 98%, covering the wireless local area network, and long-time evolution 4G at 2.5 GHz. The proposed technique uses a reflector on the ground plane, to change the parameters of the monopole planar antenna, of omnidirectional radiation pattern to a directional, maintaining the characteristics of the broadband, half-power beamwidth great than 100°, with high current density, and similar gain of a directional antenna. From the results, it has been observed that the elliptical leaf monopole antenna shows broadband characteristics, with a half-power beamwidth of 128°, wideband, the bandwidth of 500 MHz, a gain of 6.28 dBi, a current density of 13.01 A/m2, and circular polarization.

Com avanço da tecnologia e o grande volume de conteúdos na web nas últimas décadas, tem-se ampliado a utilização de fresadoras CNC (Comando Numérico Computadorizado) no meio industrial, ganhando considerável atencão na fabricação de peças. Este artigo propõe a construcão de um protótipo CNC acessível de baixo investimento destinado à fabricação de PCI (placas de circuito impresso) a fim de instigar o fortalecimento acadêmico do ensino aprendizagem em cursos de robótica educacional, contribuindo para novas prototipagens de baixo custo. Como resultado do ponto de vista didático, este se baseia em um modelo educacional para o apoio do conhecimento e experiências maker de novos alunos, demonstrando que esta tecnologia pode ser difundida para diversas escolas, incentivando a pesquisa e o desenvolvimento de novos protótipos.