# A Design Space for Virtuality-Introduced Internet of Things
## 4 Design Space for Virtuality-Introduced IoT Products  
### Preliminary Definition of the Design Space  
In this section, we present a design space to introduce the virtuality that is extracted from the survey of IoT products and the case studies. The taxonomy of IoT products was divided into Static IoT and Customizable IoT based on the analysis as described in the previous section. We define the classification of virtuality according to the physical constraints used in the real world. Virtual Aquarium persuades users to brush their teeth by expressing the virtual world using a physical display. Although it enables the users to change their behavior, there is a physical limitation. For example, virtuality can be seen by using display devices installed in the physical environment. If no physical display exists in the place, people cannot experience the virtual world offered by the virtuality. Since a physical display requires a place to be put and some physical things and might not be typically portable, it can only be used in a fixed place. For example, the user cannot see the Virtual Aquarium while he/she is outside of their home. AR technologies that use projectors encounter the same problem. In HoloMoL, a user can see the virtual objects anywhere while an HMD is attached. Therefore, HoloMoL does not have the same physical constraint as Virtual Aquarium. However, HoloMoL has another physical constraint, which is derived from the approach that enables it to visually expand physical objects. This case study enables the information that the user wants to memorize to be put into a real space. Extending the physical objects with virtuality shown on the HMD is a fundamental approach of this case study. Therefore, the user needs to access the place that allows the placement of augmented physical objects in the real world. This approach is powerful but is sometimes inadequate for introducing more abstract virtuality, such as a virtual characters. Ambient Bot does not have these constraints. Since the virtual character is floating without being subject to physical constraints, Ambient Bot is the case study that enables the strongest virtuality in these case studies. The constraints of Ambient Bot are not physical, but are restricted by the reality of the introduced virtuality. If virtuality is not believable from the users, the service may be meaningless for them. We extracted a design space for developing digital services that introduce virtuality, named Visualizing Level, which identifies how to incorporate virtuality into IoT products. Details of this design space are as follows: \begin{table}
\begin{tabular}{|p{142.3 pt}|p{142.3 pt}|} \hline
**Categories** & **Use Cases** \\ \hline
**When users like to use Ambient Bot** & Users like to receive neurons or weather forecasts when they wake up in the morning. Users like to receive content when they have free time or take a rest and have nothing to do. Users like to receive content when they are walking. Users receives potentially necessary information when he/she is not conscious of it. \\ \hline
**What type of content users like to receive from Ambient Bot** & Users like to receive social media information from the jellyfish. Users want to hear content from a lower-pitched human voice. Users like to receive news content from a human-like character. Users want Ambient Bot to aid in conversation with other people. \\ \hline
**How users like to use Ambient Bot** & Users only like to receive brief message content. Users want to see text messages in a clearer manner. In some backgrounds, the clarity of the messages is hindered by their colors and positions. Users want to choose the type of content that they receive according to their current situations. Users expect to speak with a jellyfish. Users expect that a jellyfish behaves with more jellyfish-like motions. \\ \hline \end{tabular}
\end{table} 
Table 1: Use case Analysis [47]. In this level, an IoT product displays information using a physical device. For example, Virtual Aquarium used a physical display.