## 4 Discussion
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Heuristic Evaluation Contents** & **N (\%)** & **Mean Score** & **Heuristic** \\ \hline Program errors that make it difficult to proceed with the scenario & 5 (45\%) & 2.20 & SMART 3 \\ \hline Errors related to the “symptom input” page configuration and screen information & 5 (45\%) & 1.80 & SMART 8 \\ \hline Inconvenience caused by the graphic method for inputting time & 5 (45\%) & 1.40 & SMART 11 \\ \hline Errors related to the “Health Report” page configuration and screen information & 5 (45\%) & 1.20 & SMART 7 \\ \hline Inconvenience caused by a hidden or difficult-to-operate input button & 3 (27\%) & 3.00 & SMART 6 \\ \hline Errors caused by unclear or missing pop-ups & 3 (27\%) & 2.00 & SMART 3 \\ \hline Errors caused by missing notifications for the ECG-related connection & 3 (27\%) & 1.33 & SMART 1 \\ \hline Inconsistent screen discomfort & 3 (27\%) & 1.33 & SMART 2 \\ \hline Errors related to the “Combination Drugs” page configuration and screen information & 3 (27\%) & 1.33 & SMART 8 \\ \hline Confusing screen configuration that allowed users to input the heart rate in the blood pressure input window & 3 (27\%) & 1.00 & SMART 5 \\ \hline Inconvenience for elderly individuals or people with reduced vision due to the small font size & 2 (18\%) & 2.00 & SMART 10 \\ \hline Discomfort caused by awkward or difficult-to-understand expressions & 2 (18\%) & 1.50 & SMART 2 \\ \hline Inconvenience caused by the lack of visibility of the configuration of the menu and tab at a glance & 2 (18\%) & 1.50 & SMART 6 \\ \hline Inconvenience caused by the keyboard window covering the screen when typing & 2 (18\%) & 1.50 & SMART 10 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of the heuristic evaluation of the clinical trial monitoring application. encourage the involvement of CRPs who were not specialists in software development facilitated easy participation. From the developer's point of view, the use of the WOZ methodology for communication with the CRPs needs to be actively considered. In particular, although it was not possible to conduct research on real clinical trial participants in this study, it is a unique experience for CRPs to experience the position of participants through the WOZ process. In fact, the end general usability can be greatly increased through the WOZ process because the actual end-users are generally accepting of the program that CRPs provide, and users often do not give active and negative feedback to the CRPs in the clinical environment. For interoperability and security, the creation of applications with Fast Healthcare Interoperability Resources (FHIR) as a standard was considered [36; 37]. However, because of security reasons as well as practical difficulties in recruiting a technician with FHIR-based production experience, interoperability with the hospital network was not implemented. Various solutions are also required for processing ECG data. For real-time ECG streaming, the limited server resources and bandwidth with the DMZ server caused delays in streaming. This problem was solved by transmission using a cloud server. However, this approach introduced a security issue because the cloud server was not located in the internal network. To solve the security issue, the Amazon Web Services Cloud, which is known for its relatively stable security among cloud services, was used. Only the function of viewing the ECG graph transmitted by the cloud was performed in the internal network, effectively blocking other data connections between networks. The arrhythmia detection algorithm also encountered resource issues. This problem was solved by physically separating one DMZ server into two logical servers, configuring the batch server, and processing the algorithm in the batch server. Thus, problems that occurred during the actual development process were solved within the limited available resources. Heuristic evaluation was used to confirm the direction of improvement.