LEC EIGHT

What is used to rank nodes and select the most promising one for expansion in Informed Search?

• Evaluation Function

• Cost Function

• Goal Function

Which search algorithm expands the node that seems closest to the goal?

• Greedy Search

• A* Search

• Depth-First Search

• Breadth-First Search

What evaluation function does Greedy Search use?

• f(n) = h(n)

• f(n) = g(n)

• f(n) = g(n) + h(n)

• f(n) = g(n) - h(n)

What makes a heuristic admissible in A* search?

• It never overestimates the true cost from n to the goal.

• It always underestimates the true cost from n to the goal.

• It exactly estimates the true cost from n to the goal.

• It is the same as the goal function.

Which function is used to estimate the cost of reaching the goal from a node in Informed Search?

• h(n)

• g(n)

• f(n)

Is Greedy Search complete?

• Yes

• No

Is Greedy Search optimal?

• Yes

• No

If h(n) never overestimates, what can be said about f(n)?

• f(n) never overestimates the true cost to the goal through node n.

• f(n) is always larger than the true cost to the goal through node n.

• f(n) is always smaller than the true cost to the goal through node n.

What is the difference between A* search and UCS when it comes to the cost used in the ordering of nodes?

• A* uses g(n) - h(n), while UCS uses g(n) only.

• A* uses h(n) only, while UCS uses g(n) + h(n).

• A* uses f(n) = g(n) + h(n), while UCS uses g(n) only.

Which search algorithm orders nodes by the sum of backward cost and forward cost?

• IDS

• Uniform-cost search

• Greedy search

• A* search