National University of Singapore
CS4246/CS5446
AI Planning and Decision Making
Tutorial Week 3
Jan 2021
1. You have been appointed as the lead engineer in the development team of NUSmart Shuttle Bus. Define the characteristics of the task environment in which the shuttle has to be
deployed. Support your answer with sufficient reasoning behind your choices.
(a) Comment on the observability aspect of the environment.
(b) Is the environment a single-agents, collaborative multi-agent or competitive multiagent environment? Justify your answer.
(c) Will the environment be deterministic or stochastic? Give an example scenario to support your answer.
(d) Would you model the environment to be episodic or sequential? Explain your choice.
2. Modified from [RN 10.3 Kindle Edition]
(a) Given the action schemas and initial state from the figure above, what are all the applicable concrete instances of F ly(p, f rom, to) in the state described by
At(P1 , JF K)∧At(P2 , SF O)∧P lane(P1 )∧P lane(P2 )∧Airport(JF K)∧Airport(SF O)?
(b) What is the result of executing the action Load(C2 , P2 , JF K) from the initial state?
(c) In regression or relevant-state search, we use description instead of state.
True or false: the goal in S TRIPS is a description instead of a state. Why?
(d) What actions are relevant to the description In(C2 , p)?
Tutorial Week 3
2
(e) What is the outcome of regressing the description At(C1 , JF K) ∧ At(C2 , SF O) over
action U nload(C1 , p, JF K)?
3. [RN 10.4] The monkey-and-bananas problem is faced by a monkey in a laboratory with
some bananas hanging out of reach from the ceiling. A box is available that will enable the
monkey to reach the bananas if he climbs on it. Initially, the monkey is at A, the bananas
at B, and the box at C. The monkey and box have height Low, but if the monkey climbs
onto the box he will have height High, the same as the bananas. The actions available to the
monkey include Go from one place to another, P ush an object from one place to another,
ClimbU p onto or ClimbDown from an object, and Grasp or U ngrasp an object. The result
of a Grasp is that the monkey holds the object if the monkey and object are in the same place
at the same height.
(a) Write down the initial state description in S TRIPS.
(b) Write the six action schemas in S TRIPS.