Electrical And Electronic Engineering

In this section we give a quick introduction to shape optimization problems in a rather general framework, and we discuss some of their features, especially in relation to the existence of an optimal solution. Our goal is not to give here a detailed presentation of the many problems and results in this very wide field, but only to show that several optimization problems, often very important for applications in mechanics and engineering, cannot be formulated by taking a Banach function space of the competing admissible choices: a more appropriate framework consists in taking as admissible controls the elements of a class of domains. We refer the reader interested in a deeper knowledge and analysis of this fascinating field to one of the several books on the subject [239], [11], [322], [337], to the notes by Tartar [347], or to the collection of lecture notes by Bucur and Buttazzo [144], [145]. A shape optimization problem is a minimization problem where the unknown variable runs ove...

Autonomous unmanned aerial vehicles work seamlessly within the GPS signal range, but their performance deteriorates in GPS-denied regions. This paper presents a unique collaborative computer vision-based approach for target tracking as per the image’s specific location of interest. The proposed method tracks any object without considering its properties like shape, color, size, or pattern. It is required to keep the target visible and line of sight during the tracking. The method gives freedom of selection to a user to track any target from the image and form a formation around it. We calculate the parameters like distance and angle from the image center to the object for the individual drones. Among all the drones, the one with a significant GPS signal strength or nearer to the target is chosen as the master drone to calculate the relative angle and distance between an object and other drones considering approximate Geo-location. Compared to actual measurements, the results of test...

The Internet of things concept empowered by low-cost sensor technologies and headless computers has upscaled the applicability of vibration monitoring systems in recent years. Raspberry Shake devices are among those systems, constituting a crowdsourcing framework and forming a worldwide seismic network of over a thousand nodes. While Raspberry Shake devices have been proven to densify seismograph arrays efficiently, their potential for structural health monitoring (SHM) is still unknown and is open to discovery. This paper presents recent findings from existing buildings located in Bucharest (Romania) equipped with Raspberry Shake 4D (RS4D) devices, whose signal recorded under multiple seismic events has been analyzed using different modal identification algorithms. The obtained results show that RS4D modules can capture the building vibration behavior despite the short-duration and low-amplitude excitation sources. Based on 15 RS4D device readings from five different multistorey bu...

A comparative analysis of the characteristics of experimental samples of filter materials with an orthotropic structure based on woven meshes (FMTS) and standard paper filters was carried out, which confirmed the possibility of using filter elements from FMTS for fine purification of diesel fuel in automotive equipment. Promising directions for further research in the development of effective FMTS are given.

Reflective Semiconductor Optical Amplifiers (RSOAs) are essential devices for the development of new generation networks that rely on the convergence of optical and RF communications. Despite their proven potential for direct modulation, RSOAs’ electro-optic response is limited by their finite bandwidth, which hinders their employment both for signal amplification and modulation at the data rates envisioned by the target applications. In this paper, we elaborate on exploiting a Birefringent Fiber Loop (BFL) to enhance the operation of RSOAs as intensity modulators. We apply a mathematically and computationally reduced model to simulate the RSOA response in the time domain, and correlate it with that of the BFL in the frequency domain. We validate the model’s predictions by an extensive comparison of the simulation against experimental results. The reasonable theoretical findings allow us to establish the employed model as an efficient tool for describing electrically driven RSOA ope...

This research proposes a modified metaheuristic optimization algorithm, named as improved stochastic fractal search (ISFS), which is formed based on the integration of the quasiopposition-based learning (QOBL) and chaotic local search (CLS) schemes into the original SFS algorithm for solving the optimal capacitor placement (OCP) in radial distribution networks (RDNs). The test problem involves the determination of the optimal number, location, and size of fixed and switched capacitors at different loading conditions so that the network total yearly cost is minimized with simultaneous fulfillment of operating constraints. Also, the hourly on/off scheduling plans of switched shunt capacitors (SCs) considering a modified cost objective function are obtained. The proposed ISFS algorithm has been tested on two IEEE 69-bus and 119-bus RDNs and a practical 152-bus RDN. For clarifying the effectiveness and validation of the ISFS, the simulated results have been compared with those of other ...

Robust single-frequency operation of an erbium–ytterbium glass waveguide laser based on the twisted-mode technique is demonstrated. A single-mode output power of 0.7 mW with relative-intensity-noise peak value of –90 dB/Hz has been obtained.

A simple method to measure the ytterbium-to-erbium energy transfer and the co-operative upconversion constants in a phosphate laser glass is proposed. The technique is based on the experimental acquisition of the luminescence decay from the Er3+ 4I13/2 metastable level at 1.5µm as a function of time and on a suitable fit of the experimental data. The fitting procedure relies on