## 4 Experiments and Results
### Case Study
#### 4.5.1 Example 1  
In this first example we are going to consider a user with the following preferences:  
* **Price**: low.
* **Cuisine**: bar, seafood, Spanish.
* **Special Diets**: no gluten, vegetarian.
* **Meals**: brunch, cocktails, lunch.
* **Features**: parking, private dining, high chairs, handicap accessible, free WiFi, credit cards accepted.
* **Distance**: the distance to the city centre must be as small as possible.  
The user has some flexibility in the type of food and the general services of the restaurant, but it is not as tolerant with regard to the times in which meals are served and the diet--special requirements. The values of the ELECTRE thresholds that represent this knowledge are shown in Table 8. All the social criteria are treated in the same way.  
Figures 7 and 8 show the domain and social performance tables respectively. Figure 9 shows the ranking results using only the standard criteria of the domain (left) and also taking into account the social criteria (right). As expected, the addition of the social  
\begin{table}
\begin{tabular}{l l l l} \hline \hline
**Criterion** & **Indifference** & **Preference** & **Veto** \\ \hline \hline A-Domain & & & \\ \hline Price & 0 & 1 & 2 \\ \hline Cuisine & 0 & 0.4 & No Veto \\ \hline Special Diets & 0 & 0 & 0.5 \\ \hline Meals & 0 & 0 & 0.5 \\ \hline Features & 0 & 0.4 & No Veto \\ \hline Distance & 0.5 & 1 & 3 \\ \hline B-Social & & & \\ \hline Food & 7.5 & 20 & 40 \\ \hline Price & 7.5 & 20 & 40 \\ \hline Service & 7.5 & 20 & 40 \\ \hline Ambience & 7.5 & 20 & 40 \\ \hline Anecdotes & 7.5 & 20 & 40 \\ \hline \hline \end{tabular}
\end{table}
Table 8: The values of the ELECTRE thresholds for all criteria.  
criteria derived from the analysis of the textual reviews produce changes in the ordering of the restaurants.  
Figure 7: Example 1: domain performance table. The colour indicates the degree of satisfaction, green being the worst and red the best.  
Figure 8: Example 1: social performance table. Colours have the same meanings as in the previous table.  
Figure 9: Profile 1: ranking results.  
The difference in the rankings reflects the importance of taking into account the opinions of the users expressed in the reviews. In the case of domain criteria, as it may be seen in Table 7, most of the criteria have similar values (especially those for which the user has a stronger preference). The attribute in which there is a greater difference between the restaurants is the distance to the city centre.  
Several interesting facts may be noted when considering social criteria:  
* The restaurant \"El Taller\" has better reviews than \"Barquet\" in all aspects, as shown in Figure 8, which allow it to obtain the first position when these opinions are taken into consideration. For the same reason, \"Sadoll\" and \"ELIAN Cafe\" reach the same level as \"Barquet\".
* The restaurant \"Les Fonts de Can Sala\" improves very heavily its position in the ranking when the results of the sentiment analysis are considered. In Figure 8 it may be seen that it is the only option that has perfect reviews in three of the five social criteria. \"Tarakon\" is another example of a place with very good reviews in four of the five aspects that make it improve its position in the ranking.
* The three restaurants at the bottom are not able to improve their positions, as the customers' opinions about them are not very good.  
In summary, this example shows the clear influence of the social criteria on the ranking process.