Planning

Question 1

What is STRIPS assumption?

Answer 1

STRIPS assumes that all variables not explicitly changed by action stay unchanged

Question 2

In forward planning what is the branching factor for a given state?

Answer 2

The branching factor of a state is the number actions that are legal in that state

Question 3

What are the two parts of an action in STRIPS, and what is the meaning of each part?

Answer 3

• Preconditions: a set of assignments to features that must be satisfied for the action to be legal
• Effects: a set of assignments to features that are caused by the action

Question 4

What is a node in the search space forward planning?

Answer 4

The nodes are states of a possible world, with a total assignment of values to each feature

Question 5

Explain the role of the horizon in CSP planning. How does the choice of horizon affect the behavior of the planner?

Answer 5

The horizon is the number of steps/actions taken to reach the goal state. If the horizon is too small, the planner may not reach a goal state and if it is too big, it may take unnecessary steps to reach the goal state.

Question 6

In a CSP encoding of a planning problem, what is the relationship between the number of variables in the CSP (N), the number of variable (v) and actions (a) in the planning problem, and the horizon h?

Answer 6

N = v(h+1) + ah

Question 7

In a CSP encoding of a planning problem, which variables are involved in an effect constraint?

Answer 7

Action at time t and state variable at time t + 1