## 2 Technologies Involved
### Interactive TV  
Moreover, traditionally, the most used ways to interact with intelligent systems have been mobile devices: smartphones, tablets, and PCs. However, the world of technology is continuously evolving, not only in the computer world but also in the world of television. This evolution has occurred at a hardware level going from CRT displays to LED screens, but also in another direction. Televisions have begun to incorporate digital content, and therefore a new term, SmartTV, was created. SmartTVs or intelligent TVs involve the integration of digital content, such as social networks, video portals, web browsing tools, or application execution platforms in a device traditionally used for consuming non-interactive linear content. From the 70's, with the Teletext emergence, broadcasters have always tried to develop new ways to reach viewers. The great opportunity comes with iTV [10], iTV (Interactive Television) is a way to watch TV in which the viewer can enjoy additional services (compared to the content provided by conventional television, which traditionally uses a one-way communication). The level of interactivity will depend on the possibilities of such content, from a more basic level where the user accesses this information but their actions are not communicated through a return channel, to a truly interactive experience, where the actions of the viewer with the  
Figure 1: Interactions in the Internet of Things [9] ([[http://www.buildinginternetofthings.com](http://www.buildinginternetofthings.com)]([http://www.buildinginternetofthings.com](http://www.buildinginternetofthings.com))). Reproduced with permission with [9]. Createspace Independent Publishing Platform, 2012.  
contents are reported to the diffuser through a return channel and produce a response [11]. Throughout time there have been different standards whose main focus has been the development of interactive applications for television, including HbbTV [12; 13]. It is a standard that convinces producers and television broadcasting because it standardizes the dissemination of interactive content against the \"walled garden\" model, in which the manufacturer guarantees an optimal user experience in exchange for exercising tight control over the content and applications that can run. However, the reality is that broadasters do not provide HbbTV content and most of the current TVs are not compatible with this technology, so the launch is still going slower than expected. Conversely, models that transform televisions into smart devices are taking force (i.e., ones integrating this service as part of the TV, such as Samsung or LG (and others) through alternative devices connected to it, for example, Apple TV and Google TV (now Android TV).  
The integration of television as a device for accessing the information society opens up a range of possibilities in applications development. On the one hand, Spanish people, for example, spend 246 minutes a day watching television [14], so the frequency of use compared to other media is considerably higher. Furthermore, SmartTVs propose attractive forms of interaction with the user, such as voice control, motion control, facial recognition, etc., resulting in a more motivating experience for users. Finally, the possibility of its use throughout a single input device with simple user interfaces, normally the remote control, causes greater acceptance by a broad range of user profiles.