Figure 2
A graph with a minimum set of elements allowing the verification of temporal restrictions. Besides the activity element, two other elements have temporal characteristics, account and project. Both elements work only with the start time and end time. This way, four more restrictions can be defined: Account: the start time of an account must be less than or equal to the end time; Account-Activity: an account can contain only activities executed between start time and its own execution end times; Project: the start time of a project must be less than or equal to the end time; Project-Account: a project can only contains accounts representing experiments executed between the project start and end times.