# Smart Interactive Technologies in the Human-Centric Factory 5.0: A Survey
## 2 Smart Interactive Technologies in the Human-Centric Smart Factory
### Internet of Things
#### 2.5.1 The Smart Factory Context  
The Internet of Things is expected to have a huge impact on smart and connected factories.  
**Applications: access to sensor-gathered data.** Almost any existing object or device can be linked to back-end services and become capable to gather and analyze data, elaborate them, and display additional information obtained through physical analytics, possibly leveraging on augmented reality techniques [66]. For example, in a production plant, IoT devices can be used to monitor parameters such as temperature and pressure and to consequently switch different production processes on and off. They can also be employed to monitor hazards such as harmful gas leaks and activate countermeasures such as the ringing alarms meant to alert human operators [67]. Beyond its application on the shop floor, the Internet of Things has already brought changes to the whole product lifecycle: in fact, sensor-gathered data can not only be used to show additional information to the user but also to foster research and therefore enhance the services provided. Likewise, IoT technologies can be exploited, in combination with machine learning models which run on sensor-collected data, to test product quality, thus reducing the time and cost of testing [68]. Furthermore, the Internet of Things can help enhance the supply chain infrastructure so as to improve internal and external connectivity with suppliers and customers. Among other things, IoT devices can be used to track storage conditions throughout the supply chain and to facilitate product traceability [69].  
**Applications: energy efficiency.** In the context of a smart factory project, [PERSON]. [22] proposed the pervasive installation of sensors on production lines to solve consumption management issues. To perform efficient data monitoring with the aim to manage consumption within the context of the smart factory and thus promote a more sustainable approach, all of the ever-changing fields that bring innovation to the fourth industrial revolution were involved in the projects. Technological advancements in information visualization techniques allowed fluent interactions between end-users and big amounts of data; enhancements in machine learning (see [70] for more details) and artificial intelligence engineering made the extraction of valuable information easier to perform on retrieved data; the distance between the digital and physical worlds has been shortened by the pervasive installation of sensors on the production lines and by a participatory approach to the design of the overall cyber-physical system. In a similar vein, [PERSON]. [71] suggested to exploit an IoT layer to make industrial systems more energy-efficient. Loads with such variations that can compromise power quality and increase energy usage are monitored in real time using a sensor-area network, and a central processing server is in charge of deciding which actions to take in order to optimize power consumption.  
**Enabling technologies.** Indoor positioning systems are systems which use wireless communication networks (short- to long-range) [72] and can be easily adapted to address challenges in asset management, people tracking, security, or warehouses [73], thus having direct implications in the developments of the smart factory. Many are the technologies adopted to implement localization systems, from optical sensors to sound waves sensors to electromagnetic field sensors. Among them, radio-frequency-based systems represent a key enabler technology. To this purpose, [PERSON]. [74] provided a state-of-the-art review on one particular type of radio frequency system, the radio frequency identification system commonly known as RFID that represents one of the most suitable choices due to its cost-effectiveness and energy efficiency.