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13.1 Business Process Maps 323

Fig. 13.1 (Color online) Road map of The Netherlands. The map abstracts from smaller cities
and less significant roads; only the bigger cities, highways, and other important roads are shown.
Moreover, cities aggregate local roads and local districts

Figure 13.1, for instance, shows Eindhoven as a single dot while it consists of many
roads, various districts (Strijp, Gestel, Woensel, Gestel, etc.), and neighboring cities
(e.g., Veldhoven). People interested in Eindhoven can look at a city map to see more
details.
Process models also need to abstract from less significant things. Activities can
be removed if they are less frequent, e.g., activities that occur in less than 20% of
completed cases are abstracted from. Also time and costs can be taken into account,
e.g., activities that account for less than 8% of the total service time are removed
unless the associated costs are more than € 50,000.
Aggregation is important for process mining because many event logs contain
low-level events that need to be aggregated into more meaningful activities. In
[13], it is shown how frequent low-level patterns can be identified and aggregated.
Suppose that x ={ a,b,c , a,b,b,c }, y ={ a,d,e,c , a,e,d,c }, and z =
{ d,d,d,a } are frequent low-level patterns that represent meaningful activities,