4. (30 points) Reinforcement Learning (RL) a) How do model-based learning methods in RL work? b) How do model-free learning methods in RL work? c) We talked about the following example for the model-based learning? Explain this example. Input Policy a Observed Episodes (Training) Learned Model (s, a, s') Episode 2 A Episode 1 B, east, C, -1 C, east, D, -1 D, exit, x, +10 B, east, C, -1 C, east, D, -1 D, exit, x, +10 T(B, east, C) = 1.00 T(C, east, D) = 0.75 TIC, east, A) = 0.25 B CAD A E Episode 3 Episode 4 E, north, C, -1 C, east, D, -1 D, exit, X, +10 E, north, C, -1 C, east, A, -1 A, exit, X, -10 (s, a, s') R(B, east, C) = -1 R(C, east, D) = -1 R(D, exit, x) = +10 Assume: y = 1 = No discounting