Planning

Question 1

Means-Ends Planning

Answer 1

Given:
(1) possible actions in the world
(2) start state of the world
(3) goals to be achieved

Find:
A plan to achieve the goals

Plan = sequence of actions

Plan may also be partially ordered set of actions

For a start, we consider total order planning

Question 2

Planning by Means-Ends Analysis

Answer 2

Compare the current state and the goal state. Find the differences between them. For each difference, look at what operators might be applicable. Select the operator that gets you closest to the goal state from the current state.

Question 3

Classical Planning

Answer 3

• The world is completely observable
• An action’s effects are deterministic (completely predicatable, no uncertainty)
• Any changes in the world only occur as results of an agent’s actions,
  but not “on their own”
• Implicit time: actions have no durations; time is only reflected in the order of
  actions

Question 4

Means-Ends Planning with Goal Regression

Answer 4

Search backwards from the goal in world (situation) space
* match goals to action postconditions
* action preconditions become subgoals

We stop when the operator preconditions (as subgoals) are satisfied in the
current state

Question 5

Uninstantiated Actions and Goals

Answer 5

There is some inefficiency

Our planner forces complete instantiation of actions

Uninstantiated moves and goals stand for sets of moves and goals

Question 6

Partial Order Planning

Answer 6

• There are two plans that do not interact.
• Only the order within each plan is important

However, we do not want to consider all possible arrangements of actions but a partial ordering of actions - Partial Order
Planning