# Special Issue \"Internet of Things for Smart Homes\"
## 2 A Review of the Contributions in this Special Issue  
Acknowledging that an extensive heterogeneity of use cases in various situations of the smart home with specific requirements can be realized, it is clear that no single wireless standard can satisfactorily predominate. There are several standards available on the market, developed over various frequency bands, and applying different communication protocols. Consequently, the selection of the best wireless connectivity technology for an IoT application for a smart home can be considerably challenging. The authors of [1] present a low-cost fog computing architecture for a home automation system that allows seamless communications among ZigBee and WiFi devices. The proposed approach is based on an open method that can be replicated and further validated. The suggested architecture is scalable and can include resource-constrained devices in the system that act as sensors or actuators. The results, regarding the latency, obtained in the performance evaluation, show that the fog computing approach can be harnessed for providing real-time or quasi-real-time responses. However, there is a conspicuous increment in current consumption that could be addressed by hardware manufacturers and software developers in the next generation of IoT fog computing applications. A self-powered, threshold-based wireless sensor is proposed in [2] to recognize unusual floor vibration situations. The authors develop a cantilever-type piezoelectric energy harvester to produce electric energy proportional to the amount of mechanical floor vibration. The prototype of the self-powered wireless sensor is produced, and its applicability is confirmed. A substantial relationship among floor impact sound, slab vibrations, and electric energy harvested is reported through the correlation study. Moreover, it is shown that harvested electric energy can be employed as a threshold to predict floor vibrations and the corresponding impact sound in buildings or apartments. The authors of [3] examine the performance of a dual-hop wireless/power line hybrid fading system employing an amplify-and-forward relay concerning outage probability and average bit error rate. Several mathematical methods are employed in the evaluation regarding the versatility and accuracy of the proposed method, and the influence of the hybrid fading channel and multidimensional impulse noise parameters. Some methods have promising and satisfactory results, while others could be further improved. An energy management system for smart home refers to the employment of supervisory control and data retrieval, including the production, the delivery, and distribution of the electrical network. This theory has been broadly accepted to advise the future growth trend of power grids. Energy management deals with the real-time monitoring and arranging of numerous home appliances, based on user's preferences via intelligent ambient systems controlled by a human-machine interface in smart houses, with the purpose of electricity cost minimization and energy use productivity enhancements. The authors of [4] propose a design plan for regulating a light system based on Arduino Uno microcontroller. The proposed system controls the lights based on nighttime and object detection. Meanwhile, it has capabilities to check the status of doors and to monitor objects. The hardware implementation of the suggested solution is carried with a specific prototype to validate the performance regarding simplicity, flexibility, reliability, and, mainly, the energy management. The obtained results are promising and suggest a large-scale implementation of the system proposed by the authors. The combination of several cloud energy management systems to accomplish advantages concerning the control of energy-efficient operations in smart buildings is introduced in [5]. The tests carried out in real scenarios demonstrate the improvements in both energy consumption and comfort conditions in a real pilot.