# A Personalised Emotion-Based Model for Relaxation in Virtual Reality
## Experimental Evaluation
### Results
#### 5.2.2 Adaptation Order  
As seen in the previous evaluation, the order in which adaptations occur could have an impact on the effectiveness of the adaptations and, thus, the final emotional state. To evaluate this, tests are  
Figure 11: Plots showing the evolution of the emotional states at each time step for the indoor environment. The heuristic optimiser applies the adaptations in the same order for each user. performed which change this order. Every time interval, exactly one adaptation takes place, which leads to a change of emotional values. Eight adaptations occur (_dg_, _fr_, _nl_, _al_, _cb_ on, _cb_ off, _ms_, and _lc_). Therefore, 40.320 possible permutations of these adaptations exist, however, as \"_cb_ off\" will only happen after \"_cb_ on\", only 20.160 permutations are valid. Fortunately, some more redundancies can be removed to reduce the number of permutations further down. While in indoor environments the fire (_fr_) adaptation is not present, outdoor environments do not contain artificial light (_al_), controlled breathing (_cb_), and light colour (_lc_). Therefore, the number of permutations for indoor environments is reduced to 5040 possible permutations and for outdoor to 24. To further reduce the number of permutation of indoor environments, the actions \"_cb_ on\" and \"_cb_ off\" are combined into one, lowering the number of valid permutations to 720. This leads to a simulation run time of a maximum of 12 min for indoor environments and around 25 s for outdoor environments. In total, simulating the twelve users takes approximately 45 min. The results of the simulations on the effect of changing the order in which adaptations occur are shown in Figures 12 and 13 for the outdoor and indoor environments respectively. These plots show the relaxation, averaged over all sessions of every simulated user, and the relaxation at the end of each session averaged over all users. The different sequences (_x_-axis) are first sorted by decreasing final relaxation than by decreasing average relaxation. In these plots, a relaxation value of 1 corresponds to the maximum relaxation achievable for that particular environment and user profile. This normalisation is performed to enable a proper comparison of the different user profiles. Tables 5 and 6 show the same sequences with the actual values for the averaged and final relaxation. The following sections discuss the results in more detail. Figure 12: The average relaxation over all simulations plotted for every permutation of adaptations for the outdoor environment. The adaptation sequences are sorted according to decreasing final and average relaxation. The first thing to notice for the outdoor environment in Figure 12 is that for the outdoor environment every sequence of adaptations the maximum relaxation is achieved. This implies that the order of the adaptations has no impact on the final relaxation for this set of adaptations. However, the order does have an impact on the average relaxation over each session. A higher average relaxation means that early on in the session a higher relaxation is obtained. This translates into first applying adaptions with a big impact and finishing with the lower impact adaptations. Reaching high relaxation as soon as possible is the desired outcome. Interestingly, three groups of users are observed in terms of average relaxation. Users \(1_{out}\) and \(5_{out}\) have a relaxation below the average (orange) for every permutation of the adaptations, users \(2_{out}\) and \(3_{out}\) are always above the average relaxation, while users \(4_{out}\) and \(6_{out}\) perform around the average for each sequence. This could be partially explained by the profile of the simulated users in Section 5.1. The first three user profiles are extreme cases, resulting in above or below average results. The last three are rather average users resulting in average relaxation except for user \(5_{out}\). This user shows a rather low average relaxation with little variation for different sequences.