1. An online hospital application provides a platform for patients to make an appointment with doctors, pay for appointments, view the information of medical checks, pay for medical checks, etc. Patients need to register in the system by creating an account in the system with a unique username and password. Patients can't make appointments with doctors only after the accounts are authenticated by providing identification card numbers or medical insurance numbers. The application lists all doctors of the hospital. After a doctor is selected, the schedule of the doctor is displayed. The schedule of a doctor contains several available time intervals (ATI). Each ATI could be reserved by at most 10 patients. After a patient selects an ATI, an appointment could be made and paid. At the time of an appointment, the patient comes to the doctor and the doctor may make a medical check appointment including several medical checks for the patient in the application. The patient could view the information of the medical checks and needs to pay for the medical checks before undergoing the medical checks. At the time of the medical checks, the patient comes to the hospital and undergoes the medical checks. After that, the patient can query the check results and download them after the check results have been submitted by the hospital, (4) Build an activity diagram to describe the process of making an appointment. Tips for the process: A user first needs to login into the system. Next, the system checks whether the account is authenticated. If it is not, the system switches into the authenticating page. Otherwise, the system shows the doctor ATI selecting page. After the ATI is selected, the appointment can be submitted successfully only when the ATI is reserved by not more than 10 patients. Otherwise, the system gives a notice to user and changes to the ATI selecting page