Quiz Th 4-12-’07
CompSci 171
Intro AI
Max Welling
Crossword Puzzle Robot. [10pts]
Imagine a company build a the following program into the a cell-phone.
Using the camera it would make a picture of a crossword puzzle:
Software then (perfectly) recognizes the white and black squares
and the numbers corresponding to the questions.
You are required to enter the questions manually using the keyboard,
starting with its number.
The device then connects to a server which contains a huge amount
of crossword puzzle questions and their answers and tries to solve it.
1) [2pts] Describe the Task Environment for this robot (explain all letters in `PEAS’).
2) [2pts] What are the natural abstract states for this problem?
3) [2pts] Using these abstract states, choose between the following properties of the task environment:
(you may assume the recognition software works perfectly).
a) fully/partially observable, b) deterministic/stochastic/strategic, c) episodic/sequential,
d) static/dynamic/semi dynamic, e) discrete/continuous, f) single/multi agent.
4) [2pts] We will now search for a solution. Describe a) the initial state, b) the goal state,
c) a successor function (the set of all possible actions starting at some state x), d) a path cost.
5) [2pts] We will use breadth-first-search to solve this problem.
Are we guaranteed to find a solution using BFS? Explain why or why not.
1) [2pts] Describe the Task Environment for this robot (explain all letters in `PEAS’).
Performance Measure: Is the puzzle solved
Environment: Puzzle printed on paper
Actuators: screen that shows the solution
Sensor: keyboard, camera
2) [2pts] What are the natural abstract states for this problem?
Partial filled out puzzles. Order questions and at level d there are possible answers to the first
d questions.
3) [2pts] Using these abstract states, choose between the following properties of the task environment:
a) fully/partially observable,
b) deterministic/stochastic/strategic,
c) episodic/sequential,
d) static/dynamic/semi dynamic,
e) discrete/continuous,
f) single/multi agent.
4) [2pts] We will now search for a solution. Describe
a) the initial state – empty puzzle
b) the goal state – solved puzzle
c) a successor function – all possible answers to the next question in some ordering consistent with previous
answers in that branch.
d) a path cost. constant cost per solved question
5) [2pts] We will use breadth-first-search to solve this problem.
Are we guaranteed to find a solution using BFS? Explain why or why not.
YES: we will always find a solution at level d where d is the number of questions. All states higher in the tree
are partial solutions. BFS scans all possible solutions to the puzzle.