# A Design Space for Virtuality-Introduced Internet of Things
## 3 Analysis of Current IoT Products and Services that Introduce Virtuality
### Case Studies of Digital Services Introducing Virtuality
#### 3.2.2 HoloMoL  
HoloMoL is a Microsoft HoloLens application for augmenting human memorization that applies the Method of Loci (MoL) technique [46]. The MoL is a memorization method that relates to the space that a person knows well with the information he/she wants to remember [50]. The place is a palace created in an image. This method improves an ability of human memorization, for example, a person can remember the figure of \(\pi\), which is the circle ratio, by using the method. This technique enables effective memorization by combining spatial memory and associative memory. When using MoL, people need to be able to accurately imagine a palace and know the detail of the palace. For example, the palace must be able to accurately represent the type of the layout, room, furniture, and lighting, and how things are placed. It is an unaffordable method because training is necessary to be able to imagine the imaginary space accurately. HoloMoL aims to use MoL without training by applying AR technologies provided by HoloLens to make MoL available to the users in the real world. As a result, many people can remember more information. HoloMoL realizes MoL in the real space by displaying information that corresponds to a gazed object with AR technologies. Because HoloMoL can be used in the space where the users live on a daily basis, the system satisfies MoL's \"well-known place\" condition. By enabling the users to place information that they want to remember, they can remember the location and the information in the same manner as the original MoL. In the prototype, AR markers were installed in the real world, and the information that the users want to remember was displayed when the users saw the markers. This prototype was developed using Unity and Vuforia. Unity is utilized as a platform to render a 3D object in the real space and Vuforia is adopted to recognize fiducial markers and to provide a database function that associates the image of each marker to be recognized with the corresponding information to be displayed in the real space. When the marker is recognized, the database is referenced and the corresponding information is displayed as a sequence of characters written on a plate-shaped object, as shown in Figure 2.  
We conducted an experiment to investigate how people would utilize HoloMoL to associate information with places for memorizing the information. We recruited six participants: 20- to  
Figure 2: When a user watches at the marker (**Right**), the associated information is displayed (**Left**). 23-year-old Japanese college students (4 males and 2 females with an average age of 21.7). The task of the experiment is to memorize and recall ten African nations, for example, Botswana. We chose nations that are unfamiliar to many young college students. After the memorization phase, participants were asked several questions that required recalling the descriptions. After the task, each participant was interviewed and took a short questionnaire. We analyzed the observed participants' behaviors and gathered interview results to understand participants' fiducial marker placements to accomplish the target task. The results indicated three different methods to place information:  
1. Association-based method: People who used this method associated an environment's physical objects with the intended information to memorize. For example, when a participant had to memorize the description about Niger, she imagined water from Niger because the description suggests that Niger had an image of water; thus, she placed a corresponding marker near water bottles. Another participant said that she chose a place related to water because the marker's texture looks like water. 2. Category-based method: The participants categorized the information to be memorized and then placed the similarly categorized information spatially close to each other.