Resumo em Inglês:

Abstract Monte Carlo simulations are widely used in analysis of interference between radiocommunication systems. The method performs n random experiments, each called an event, snapshot, or trial, to estimate the statistics of some parameter of the problem (for instance, the interference level). There is no formalization about the number of events necessary to run a simulation. In practice, this is often done based on the intuition of the analyst about the model. In this paper, we propose how to choose a number of events for Monte Carlo simulations. We address this issue by understanding that the protection criteria for radiocommunication systems are usually related to a quantile of the result, and then calculating the number of events for which it is also possible to estimate a confidence interval for it. Results show that, for a confidence level of 99.9%, it is possible to estimate confidence intervals for p-quantiles for p up to 99.89% with 10000 events.

Resumo em Inglês:

Abstract This work presents the development of a refractive index sensing methodology for measuring carbon dioxide concentrations, considering the effect of temperature environment. We propose and demonstrate, using simulations, the use of tapered and coated Long Period Gratings as a way to enhance the refractive index sensitivity. In addition, artificial neural networks were used to improve the estimation of carbon dioxide concentration, considering the crosssensitivity effect with temperature.

Resumo em Inglês:

Abstract Electromagnetic problems with moving structures are considered. For objects moving at a uniform velocity, the most popular technique used in the literature consists of a change of the reference frame and the utilization of Lorentz transformation of Maxwell’s electric and magnetic fields and Voigt-Lorentz transformations of space and time variables. In order to account for non-uniform motions, a numerical approach based on the finitedifference time-domain (FDTD) method is used. In this approach, Maxwell’s equations are applied without modification and the motion of objects is implemented by changing their positions in the FDTD time loop. Three types of movements are considered: vibration, rotation, and acceleration. Full-wave numerical results are reported for different objects in motion: observer, source, and reflecting electromagnetic surface. In all the problems analyzed, interesting results are obtained and these results are discussed in detail.

Resumo em Inglês:

Abstract The effect of mechanical stress on hysteresis losses of electrical steel sheets is investigated in this paper. Experimental data obtained from a dedicated bench are used in a curve fitting procedure to analyze the parameters behavior for a hysteresis losses model over a range of mechanical compressive and tensile stresses. By applying the concept of equivalent stress, a finite element model is simulated, and the hysteresis losses are a posteriori calculated considering an equivalent stress distribution over a single-phase induction motor stator.

Resumo em Inglês:

Abstract The rapid development of the Fifth Generation (5G) networks encourages researchers to improve the Radio over Fiber (RoF) technique to achieve data rates of 10 Gbps and beyond. That led to a significant increase in bandwidth and range while reducing latency and cost. This paper evaluates an Analog Radio over Fiber (ARoF) technique compatible with Next-Generation (NG) long-haul communication systems, aiming for simplicity and lower cost. Transmitting a 28 GHz, 256 Quadrature Amplitude Modulation (QAM) signal through Single-Mode Fiber (SMF) is possible by modulating it through two parallel Mach-Zehnder Modulators (MZM), allowing signal reception over long distances. The Error Vector Magnitude (EVM) appraises performance of the system. The simulation results indicate that the prototype can transfer data at 10 Gbps through the optical link up to 570 km with an EVM of 3.375% and received optical power of 4.015 dBm. The proposed system supports a high bit rate and maintains the EVM within 3GPP limits, making it superior to peer publications and highly appropriate for NG long-haul communication systems.