# ScientIST: Biomedical Engineering Experiments Supported by Mobile Devices, Cloud and IoT
## 4 Results
### Usability and User Experience  
To assess the perception and satisfaction of the students regarding the proposed approach, a class of 19 students (10 female) was asked to answer a feedback survey, as a result of using our workflow. A survey was performed, including two closed-ended questions. Firstly, the user was asked to select one of six response options for the question \"How would you rank your technical skills?\". Secondly, we used the System Usability Scale (SUS), which is a widely used approach to collect qualitative data related with measurable usability criteria. It is implemented through individual interviews with prospective users, consisting in ten item questionnaire with five response options. The SUS provides an accurate and widely accepted means to determine the degree of user satisfaction with respect to a given system [13].  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Participant** & **Decibel Source (\%)** & **AccX (\%)** & **AccY (\%)** & **AccZ (\%)** \\ \hline
1 & 38.84 & 43.61 & 37.91 & 47.15 \\
2 & 0.37 & 0.37 & 0.37 & 0.51 \\
3 & 100.0 & 100.0 & 100.0 & 1  
Those were followed by four open-ended questions: \"What are the main advantages you see in the proposed system?\", \"Do you see yourself using this system beyond the scope of this experiment and, if so, in which cases?\", \"Are there any specific features or functionalities that you would like to see implemented?\", and \"What would you say are the main limitations of the system?\".  
The SUS has a minimum score of 0 and maximum score of 100. Hence, each of its ten questions leads to a score within 0 and 10. A user should answer all items, and in case they feel unable to respond to one of the items, they should mark the center point of the scale. The general SUS questionnaire was adjusted by replacing the word \"website\" in every question with \"system\".  
It is generally posed to the user after they tested the system, prior any debriefing or discussion. Moreover, users are asked to record their immediate responses, rather than thinking about the items for a long time. This scale has had a great success among usability practitioners, for being a quick and easy-to-use usability measure [14]. According to [PERSON] et al. [15] the SUS is not biased against certain types of user interfaces or against gender.  
The overall results suggest that the proposed methodology is easy to use and enables a short learning curve, with an average score of 78.68% (\(\pm\)15.28% standard deviation), and the average results obtained for each of the 10 items of the SUS are illustrated in Figure 8. The obtained results showed average scores above 7.5 for nine of the items, except for the first one \"I think that I would like to use this system frequently\", which lead to an average score of 5.66.  
The best user feedback was obtained on the item \"I think that I would need the support of a technical person to be able to use this system\", with an average score of 8.68, highlighting the ease-of-use of the overall workflow and its capability of empowering the students to feel confident using it independently.  
A salience analysis of the answers to the open-ended questions revealed as positive aspects the \"ease of use\", \"handiness\", and the \"portability\" of the system, enabling the students to conduct experiments \"everywhere\". Limitations identified by the students were mostly related with the lack of other sensors beyond the PPG, the dependency on the accuracy of the sensors embedded in each phone, and the lack of a computer-based application to communicate with the SCB.  
Furthermore, students reported that they found it easier to study using the journal, organized and illustrated with the images taken during the experiment, rather than using the notes they took from the class.  
Figure 8: Results obtained on the 10-item System Usability Scale (SUS) used to collect the feedback of the enrolled students.