Abstract
Every player in the business world is constantly looking for a competitive advantage which will place them in a leadership position in their particular market. When chosen correctly, lighting may have a significant influence on consumers’ decisions to enter a retail shop or buy a certain item. However, the illumination theme does not only apply to physical purchases, in the retail environment, but also to advertisements and online shopping. Hence, this article aims to study light characteristics and the temperature of light which best emphasize product quality, making them more appealing to the customer. Thus, an online survey was performed, which had 130 answers. After analysing the data, we concluded that a desire exists that retail firms act honestly, and that they should thus use lighting which does not distort the perceived images (which should be as real as possible) of the products which are for sale.

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. © Springer Nature Switzerland AG 2020.

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.