The paper presents the electronic wallet solution implemented within a GSM SIM technology for accessing public services. The solution is implemented in the medical field to provide information on the patient's medical history and payment for private medical services. The security issue is a very...

Depending on the time of solving a received task the users are categorized in many categories. In the paper structures of time intervals are determined for establishing types of users and models to determinate the users’ collectivities according to the time needed for solving the users’ tasks.