In the context of VES modeling, what is the difference between a smooth model and a layered model?

There are two UML diagrams types for describing dynamic models: StateChart diagrams and Interaction diagrams. Let’s focus on interaction diagrams. Interactions diagrams can be categorized into two types: Communication diagram and sequence diagram. Let’s reduce our focus on the sequence diagram. The structure of the sequence diagram helps us to determine how decentralized the system is. We distinguish two structures for sequence diagrams. What are those two structures (or diagrams)? And when do we choose each structure?

Write the differences between composition and aggregation relations of UML diagram with examples.

You are to produce a report on Model-based RL and Model-free RL. Discuss about Model-based and Model-free RL. Compare the algorithms of Model-based vs. Model-free RL.