Recently, a method for estimating permittivity distributions was reported. The method combined a numerical technique (Finite Element Method) with Genetic Algorithm (GA). However, methods for estimating the distributio...
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Improving the use of energy resources has been a great challenge in the last years. A new complex scenario involving a decentralized bidirectional communication between energy suppliers, distribution system and consum...
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Improving the use of energy resources has been a great challenge in the last years. A new complex scenario involving a decentralized bidirectional communication between energy suppliers, distribution system and consumption is nowadays becoming reality. Sometimes cited as the largest and most complex machine ever built, Electric Grids (EG) are been transformed into Smart Grids (SG). Hence, the load forecasting problem has become more difficulty and more autonomous load predictors are needed in this new conjecture. In this paper a novel method, so-called MSES, bio-inspired by Evolution Strategies (ES) combined with Multi-Start (MS) procedure is described. This procedure is mainly based on a self-adaptive algorithm to calibrate the parameters of the fuzzy rules. MSES was implemented in C++ via OptFrame framework. Our main goal is to evaluate the performance of this algorithm in a grid environment. Real data from an electric utility have been used in order to test the proposed methodology. The obtained results are fully described and analyzed.
This paper presents a topology based on the interconnection of single-phase H-bridge converters and a three-phase converter acting as a shunt active power filter. Contributions for the model, PWM approach and control ...
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This paper reports an effective method of packaging a fiber Bragg grating (FBG) for the simultaneous measurement of temperature and strain. The technique consists of embedding two fiber Bragg grating sensors inside a ...
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This paper presents a new multi-scale place recognition system inspired by the recent discovery of overlapping, multi-scale spatial maps stored in the rodent brain. By training a set of Support Vector Machines to reco...
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ISBN:
(纸本)9780980740448
This paper presents a new multi-scale place recognition system inspired by the recent discovery of overlapping, multi-scale spatial maps stored in the rodent brain. By training a set of Support Vector Machines to recognize places at varying levels of spatial specificity, we are able to validate spatially specific place recognition hypotheses against broader place recognition hypotheses without sacrificing localization accuracy. We evaluate the system in a range of experiments using cameras mounted on a motorbike and a human in two different environments. At 100% precision, the multiscale approach results in a 56% average improvement in recall rate across both datasets. We analyse the results and then discuss future work that may lead to improvements in both robotic mapping and our understanding of sensory processing and encoding in the mammalian brain.
In this paper, a new approach to the topology configuration problem in the Island Model (IM) is proposed. The mechanism proposed works with a pool of candidates for migration and the choice of immigrants is performed ...
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ISBN:
(纸本)9781450319645
In this paper, a new approach to the topology configuration problem in the Island Model (IM) is proposed. The mechanism proposed works with a pool of candidates for migration and the choice of immigrants is performed using the usual selection techniques of evolutionary algorithms. Computational tests on IM versions of the Differential Evolution show positive effects of the proposed approach in terms of the number of function evaluations required for convergence.
We have developed an MR compatible PET insert prototype to enable simultaneous PET-MR imaging of small animals inside a 7T animal MR imaging system. The 16 detectors in this system are based on the SensL SPMArray4B si...
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ISBN:
(纸本)9781479960989
We have developed an MR compatible PET insert prototype to enable simultaneous PET-MR imaging of small animals inside a 7T animal MR imaging system. The 16 detectors in this system are based on the SensL SPMArray4B silicon photomultipliers (SiPMs) and dual layer offset LYSO crystal blocks with crystal size of 1.2 × 1.2 × 4 mm~3 in the top layer and 1.2 × 1.2 × 6 mm~3 in the bottom layer, with 409 total crystals per detector. Each detector was evaluated by generating flood histogram images and measuring per-crystal photopeak amplitude and energy resolution. The system was tested for MR compatibility and no visible artefacts were seen in the MR images or in the PET detector flood images. The temperature of the detector modules was monitored and found to stabilize after approximately two hours of operation between 32℃ and 34℃. Photopeak amplitude, energy resolution and count rates recorded per crystal were studied at a baseline temperature of 30℃ and at temperatures ranging from 20℃ to 40℃ in increments of 2℃. When bias voltage to the detectors was fixed at the value corresponding to an overvoltage of 2.5V at 30℃, the photopeak amplitude changed by as much as 19% and 28% at 20℃ and 40℃ respectively. Energy resolution and count rates demonstrated similar degrees of change. Maintaining a fixed overvoltage at each temperature point reduced but did not completely eliminate the change in these output characteristics. A lookup table based on empirical measurements was employed for the adjustment of bias voltage at different temperatures to maximize the stability of detector modules. Measurements obtained by using this lookup table method demonstrate better stability when compared to results obtained by using a fixed overvoltage.
This paper presents a proposal for Isolated Bidirectional battery charger. The charger in study has capacity to supply power 1.34KVA in a line of 400V DC and battery charging capability up to 5A at 192V nom . For iso...
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This paper presents a proposal for Isolated Bidirectional battery charger. The charger in study has capacity to supply power 1.34KVA in a line of 400V DC and battery charging capability up to 5A at 192V nom . For isolation of the batteries and improve energy efficiency in the conversion was used Planar transformer coupled to the switching transistors IGBTs for low losses. To control the energy flow in both directions was used Full-Bridge Converter suitable for the power level required at 400V bus. The charging of the batteries can be integrated into a network-smart grid, composed of renewable energy sources like photovoltaic and / or wind, or be used in UPS systems "double conversion", whose load is less fault tolerant power.
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