Over 40% of nursing home residents in the Netherlands are estimated to have visual impairments. In this study, light conditions in Dutch nursing homes were assessed in terms of horizontal and vertical illuminances and colour temperature. Results showed that in the seven nursing homes vertical illuminances in common rooms fell significantly below the 750 lx reference value in at least 65% of the measurements. Horizontal illuminance measurements in common rooms showed a similar pattern. At least 55% of the measurements were below the 750 lx threshold. The number of measurements at the window zone was significantly higher than the threshold level of 750 lx. Illuminances in the corridors fell significantly below the 200 lx threshold in at least three quarters of the measurements in six of the seven nursing homes. The colour temperature of light fell significantly below the reference value for daylight of 5000 K with median scores of 3400 to 4500 K. A significant difference in colour temperature was found between recently constructed nursing homes and some older homes. Lighting conditions of the examined nursing homes were poor. With these data, nursing home staff have the means to improve the lighting conditions, for instance, by encouraging residents to be seated next to a window when performing a task or during meals.
A modified genetic algorithm (MGA) optimization procedure, alongside time series machine learning (ML) classifiers, is proposed to minimize handovers in a digital twin-based visible light communication (VLC) system. Frequent handovers have a direct impact on the overall performance of the VLC system due to the inherent connection downtime of a handover process. The handover scheme proposed in this article considers the receiver trajectory information to minimize handovers, maintaining the system performance below the forward error correction limit. Simulation results indicate that the proposed scheme outperforms a power-based handover scheme, achieving handover reductions of 42.47%. Therefore, the MGA combined to the ML models approach is an effective means of minimizing handovers, as well as improving overall VLC system performance.