Abstract
Recommendation systems try to guide the users in carrying out a task providing them with useful information about it. Considering the context of software development, programs are ever-increasing, making it difficult to conduct a detailed verification and validation. Automated static analyzers help to detect possible faults on software products earlier and quickly but, in general, the issue maybe a false-positive warning. In this sense, this work presents and evaluates a recommendation system, called WarningsFIX (WFX), which combines several static analyzers aim at: i) Expand the possible fault domain approached by each static analysis tool increasing the range of warnings types covered, allowing the concentration of a higher number of true-positive warnings. ii) Establish different prioritization strategies of warnings aiming at suggesting for reviewers first analyze the ones with a higher chance of being true-positive. WFX organizes the warnings information via treemaps considering four levels of abstraction: program, package, class, and line the nodes of the treemap on each level may be classified by three different prioritization strategies based on the number of warnings, the number of tools, and the suspicions rate the use of these strategies enables the reviewer to handle the set of warnings in a coordinated way depending on the cost and time constraint available. We perform a feasibility study to evaluate the WFX effectiveness whose results shown that: i) WFX was able to improve the results obtained from combined static analyzers to 44% of the analyzed programs, concentrating for them a greater number of true-positives. ii) WFX, depending on the adopted prioritization strategy, improved from 67.5% to 55% the ranking of lines with real bugs when compared with the list of warnings provided by the automated static analyzers without the WFX support.

Abstract
This paper reports on the development and validation of a formal model for an automotive adaptive exterior lights system (ELS) with multiple variants in Electrum, a lightweight formal specification language that extends Alloy with mutable relations and temporal logic. We explore different strategies to address variability, one in pure Electrum and another through an annotative language extension. We then show how Electrum and its Analyzer can be used to validate systems of this nature, namely by checking that the reference scenarios are admissible, and to automatically verify whether the established requirements hold. A prototype was developed to translate the provided validation sequences into Electrum and back to further automate the validation process. The resulting ELS model was validated against the provided validation sequences and verified for most of requirements for all variants.

Abstract
Long period fiber gratings (LPFGs) were fabricated in a standard single mode fiber (SMF-28e) through femtosecond (fs) laser direct writing. LPFGs with longer and shorter periods were fabricated, which allows coupling from the fundamental core mode to lower and higher order asymmetric cladding modes (LP(1,6)and LP1,12, respectively). For the grating periods of 182.7 and 192.5 mu m, it was verified that the LP(1,12)mode exhibits a TAP at approximately 1380 and 1448 nm in air and water, respectively. Characterization of the LPFGs subjected to high-temperature thermal treatment was accomplished. Fine-tuning of the resonance band's position and thermal stability up to 600 degrees C was shown. The temperature sensitivity was characterized for the gratings with different periods and for different temperature ranges. A maximum sensitivity of -180.73, and 179.29 pm/degrees C was obtained for the two resonances of the 182.7 mu m TAP LPFG, in the range between 250 and 600 degrees C.

Abstract
In this paper, we describe the design of a dual polarized packaged patch antenna for 5G communications with improved isolation and bandwidth for K-band. We introduce a differential feeding technique and a heuristic-based design of a matching network applied to a single layer patch antenna with parasitic elements. This approach resulted in broader bandwidth, reduced layer count, improved isolation and radiation pattern stability. The results were validated through finite element method (FEM) and method of moments (MoM) simulations. A peak gain of 5 dBi, isolation above 40 dB and a radiation efficiency of 60% were obtained.

Abstract
Switched reluctance machines are simple, robust, fault-tolerant and do not use permanent magnets, which makes them a strung candidate fur vehicular propulsion. Despites the advantages they still stiffer from high torque pulsation and acoustic noise, which can be reduced by the controller. In this paper the concern is in having an advanced current control, so it is used the model predictive control (MPC). This requires an accurate model to estimate the future behavior of current and the back-electromotive force (emf) signal is essential. As this signal cannot be directly calculated or measured it is proposed a new algorithm to calculate its estimation in real time. The algorithm is easy to implement and the numerical results show the accuracy of the method, which permits a very low current estimation error in the MPC framework.

Abstract
The presence of Industrial IoT systems on the factory shop floor in recent years, are becoming an attractive solution with many advantages, including flexibility, low cost and easy deployment. As more and more devices are wirelessly connected, spectral noise level increases and consequently radio interference between IoT devices. In this paper, we present an agnostic methodology to assess radio interferences between different industrial IoT systems on the factory floor, using appropriate propagation models. Several interference scenarios are simulated, ranging from legacy systems to future communication standards implementations (5G). We highlight some of the challenges and open issues that still need to be addressed to decrease interference and make industrial wireless systems compatible. © 2020 IEEE.