# Implementing and Evaluating a Font Recommendation System Through Emotion-Based Content-Font Mapping
## 4 Font Recommendation System through Content Emotion Analysis  
The emotional values of fonts measured in Section 3 are ultimately utilized to implement a system that recommends fonts suitable for the extracted emotions of content based on user expressions and text content input. However, the emotional criteria for fonts and content differ. Therefore, two models for calculating the similarity between content emotions with different classification criteria and font keywords are designed. A comparison of the models is conducted to select the computational model, which, once chosen, can be applied to the implementation of the font recommendation system. The \"PAD model\" [18] is a framework often used to describe emotions and affective states. It breaks down emotions into three fundamental dimensions:  
* Pleasure: This dimension represents how pleasant or unpleasant an emotion is. Positive values indicate pleasurable emotions, while negative values indicate unpleasant ones. * Arousal: Arousal measures the intensity or excitement level of an emotion. High values indicate highly aroused emotions, while low values represent calm or low arousal emotions. * Dominance: This dimension reflects the sense of control or dominance associated with an emotion. Positive values represent emotions where the person feels in control or dominant, while negative values signify emotions where the person feels submissive or not in control. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **DOSGothic [(ex) \(\oplus\)\(\oplus\)\(\oplus\)\(\oplus\)]** & \\ \hline \(<\)Emotional keywords\(>\) & High & Medium & Low \\ angular & 20 & 32 & 9 \\ attention-grabbing & 13 & 17 & 31 \\ boring & 20 & 13 & 28 \\ calm & 4 & 24 & 33 \\ delicate & 1 & 19 & 41 \\ disorderly & 22 & 23 & 16 \\ dramatic & 12 & 14 & 35 \\ formal & 2 & 6 & 53 \\ friendly & 11 & 17 & 33 \\ gentle & 3 & 20 & 38 \\ graceful & 0 & 5 & 56 \\ modern & 1 & 22 & 38 \\ playful & 10 & 20 & 31 \\ strong & 1 & 17 & 43 \\ technical & 3 & 10 & 48 \\ warm & 3 & 15 & 43 \\ determined & 3 & 12 & 46 \\ harmonious & 0 & 11 & 38 \\ stiff & 29 & 20 & 12 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of the emotional keyword survey for DOS Gothic font, by the number of respondents. The PAD model is commonly used in psychology and emotion recognition research. It is also applied in various fields, such as product design, advertising, and user experience design, to better understand and design for emotions and affective responses. By using this model, emotions can be described and analyzed in a more precise and structured manner, aiding in the improvement of products, services, and user interactions. In this study, two calculation models were designed utilizing the emotional values derived from the PAD model, as described above. In Section 4.1, the model is explained, which recommends fonts based on distance calculation after converting the emotions of content and fonts into PAD values. Additionally, Section 4.2 elucidates the calculation model that determines similarity by calculating the correlation between the emotional classification criteria of content and font keywords using the Pearson correlation coefficient. Finally, in Section 4.3, the font recommendation results obtained through each calculation model are evaluated, and the final calculation model to be applied to the content-font mapping model is selected. Additionally, in the experiments in Sections 4.1 and 4.2, using the maximum number of fonts could be effective. However, since the task involves classifying each font into 19 keywords, the workload increases with the growing number of fonts. This could potentially induce fatigue in evaluators, leading to reduced reliability in the results of the later stages of the evaluation. Therefore, in this study, we decided to select a representative minimum of fonts based on font classification for application in experiments. We collected over 200 fonts that are highly preferred by users and are available for free.