# Evaluation of Emotions from Brain Signals on 3D VAD Space via Artificial Intelligence Techniques
## 4 Discussion
Comparisons of segments III, IV, and V can be seen more clearly in this sub-study. Different colored lines, including data points of related classifiers in the figures, indicate the segmentations. Blue, green, and purple colored lines correspond to Segments III, IV, and V, respectively. More opening parts in the middles of the figures mean the segment separations are closer. SMOTE versions of each figure in this part of this study show that those openings in the middle parts are increased compared to the unbalanced ones (Figure 9b, Figure 10b, Figure 11b, and Figure 12b). As such, the results of the segment classifications are closer to each other. Class separations 5, 4-6, and 3-7 are used for the A&G, B&H, and D&F emotion comparisons. Class separations 5, 4.5-5.5, and 4-6 are used for the C&E emotion comparisons. Sizes of the same colored lines (segments) indicate the class separations in the figures. Balanced data results (SMOTE versions) use the same colors and sizes for segments and classes. Class separations with the related segments are stated on the right sides of the unbalanced results in Figure 9a, Figure 10a, Figure 11a, and Figure 12a. It can be easily seen from those lines that data accuracy increases gradually as the class separations diverge from the midpoint (5) of the VAD space for most of the classifications. For instance, the 3-7 class separation has higher accuracy values than the 4-6 separation, and the 4-6 is bigger than the 5 separation for most classifications. In this study, classes are set by considering the high and low values of the valence, arousal, and dominance scores. Class placements on VAD space are shown in Figure 15, in which the emotions are placed in the eight regions. To simplify understanding, the valence dimension is considered high and low (not as positive or negative), just like this study's other dimensions (valence and dominance). [PERSON] et al. [3] considered six basic emotions in their study: anger: low V, high A, D [6; 7]; joy: high V, high A, D [6; 7]; surprise: high V, high A, D [4; 5]; disgust: low V, high A, D [5; 6]; fear: low V, high A, D [3; 4]; and sadness: low V, low A, D [3; 4] for a 1-9 scale, as low indicates [1; 5] and high indicates [5; 9] intervals. Looking mainly at Figure 15 and considering the 3D emotion space figures in [50] and [51] and the definitions in [3], we generally considered and inferred the eight three-dimensional emotion regions as:  
A: Happy, joyful, useful, powerful, influential, friendly, excited, and inspired B: Relaxed, leisurely, untroubled, and satisfied C: Disdainful and unconcerned D: Angry, hostile, cruel, insolent, hate, and disgusted E: Impressed, surprised, thankful, and curious F: Protected, humble, and reverent G: Sad, depressed, bored, lonely, feeble, discouraged, and discontented H: Fearful, frustrated, helpless, pain, humiliated, embarrassed, guilty, and confused  
According to this information, we can state four cross-comparisons of VAD space in a briefer way as:  
A&G (Happy, joyful, excited, and powerful and sad, depressed, and feeble) B&H (Relaxed, leisurely, and satisfied and fear, pain, and guilt) D&F (Angry, hate, and disgusted and protected, humble, and reverent) C&E (Disdainful and unconcerned and impressed, surprised, and thankful). Figure 15: VAD space of emotions with class placements (VAD space is drawn by using the data in [14] and taking the pleasure plane as valence). The class placements are marked on the figure. Glancing at this inferred information, for the emotion regions with high valence values, which are A and B (with high dominance values) and E and F (with low dominance values), generally, we see positive emotions. On the other hand, for emotion regions with low valence values, which are G and H (with low dominance values) and C and D (with high dominance values), generally, we see negative emotions in accordance with the literature.