What does synchronization bars in an activity diagram represent?

Synchronization bars in an activity diagram are used to represent parallel processing of tasks. They serve as nodes that indicate where multiple activities can occur simultaneously and then converge back into a single flow. This visual representation helps to illustrate how different tasks can be executed at the same time, enhancing understanding of concurrent processes within a workflow.

In the context of understanding workflow dynamics, synchronization bars clarify that once the activities that are running in parallel have completed, control can then flow back to subsequent activities. This feature is essential for modeling processes where tasks do not depend on one another and can proceed independently, allowing for more efficient use of time and resources in project planning and execution.