Table 1: Six aspects of function.
| Aspect | Description |
| Input | Input to the functions, Trigger |
| Output | Outcome of functions |
| Precondition | Conditions that must be satisfied before functions are carried out |
| Resource | What is consumed during the process (fuel, energy, labor force...) |
| Control | What supervises or restricts the function |
| Time | Time required to accomplish the process |