1
CPSC 322, Practice Exercise
Conditional Independence
1
Directed Questions
Describe the difference between marginal independence and conditional independence.
Why are we more often interested in conditional independence?
What are the three key compone
1
CPSC 322, Practice Exercise
Variable Elimination
1
Directed Questions
What is a factor?
What are the operations applied to factors in the variable elimination algorithm?
What do we mean by the belief network inference problem?
Define elimination ord
1
CPSC 322, Practice Exercise
STRIPS planning
1
Directed Questions
The STRIPS representation for an action consists of what?
What is the STRIPS assumption?
What is the frame problem in planning? How does it relate to the STRIPS assumption?
What are so
1
CPSC 322, Practice Exercise
Logic: Syntax
1
Directed Questions
In propositional definite clause logic (PDCL),
What is an atom? Give the definition and an example.
What is a body? Give the definition and an example.
What is a definite clause? Give the
1
CPSC 322, Practice Exercise
Arc Consistency
1
Directed Questions
What does it mean for an arc to be consistent?
How can we enforce consistency of an arc hX, r(X, Y )i ?
What does it mean for a network to be arc consistent?
What are the possible outc
1
CPSC 322, Practice Exercise
SLS for CSP
1
Directed Questions
In local search, how do we determine neighbours?
What is the difference between random walk and random restart?
What is the key weakness of stochastic local search?
2
Traffic Flow
Consider
1
CPSC 322, Practice Exercise
Single-Stage Decision Networks
1
Directed Questions
What is meant by a one-off decision? How can this be applied in the delivery robot
example?
Define utility in a decision problem.
How do we calculate the expected utility
1
CPSC 322, Practice Exercise
CSP planning
1
Directed Questions
What is meant by the horizon in a planning problem?
What are initial state constraints in a CSP problem?
What are goal constraints?
What are precondition constraints?
What are effect con
1
CPSC 322, Practice Exercise
Branch and Bound
1
Directed Questions
In branch and bound (B&B), how is the upper bound (UB) calculated?
How is the lower bound (LB) calculated for a path?
With B&B, when do we prune a path?
2
Heuristic Search
Consider the
1
CPSC 322, Practice Exercise
Sequential Decisions
1
Directed Questions
How is a sequential decision problem different from a one-off decision problem?
What types of variables are contained in a decision network?
What can arcs represent in a decision n
1
CPSC 322, Practice Exercise
Logic: Proofs
1
Directed Questions
Given a knowledge base KB and a conjunction of atoms g, what is meant by KB |= g?
Given a proof procedure P, a knowledge base KB and a conjunction of atoms g, what is
meant by KB `P g?
De
COGS 300 Fall 2013
Assignment 2
Due: 11:00am, Tuesday 26 November 2013 (hardcopy in class and email to cogs300@gmail.com)
This can be done in groups of size 1, 2 or 3. Working alone is not recommended. All members of the
group need to be able to explain t
1
CPSC 322, Practice Exercise
Heuristic Search
1
Directed Questions
What is the distinction between informed and uninformed search?
What is a heuristic?
When is a heuristic admissible?
A* can be seen as a combination of what two search strategies?
2
H
1
CPSC 322, Practice Exercise
Uninformed Search
1
Directed Questions
What is meant by search algorithm completeness?
What is meant by search algorithm optimality?
What are the advantages of breadth-first search (BFS) over depth-first search (DFS)?
Wha
1
CPSC 322, Practice Exercise
Solutions to Logic: Proofs
1
Directed Questions
Given a knowledge base KB and a conjunction of atoms g, what is meant by KB |= g?
Answer: g is a logical consequence of KB, that is, it is true in every model of KB
Given a pr
1
CPSC 322, Practice Exercise
Solutions to Single-Stage Decision Networks
1
Directed Questions
What is meant by a one-o decision? How can this be applied in the delivery robot
example? Answer: The agent knows which actions are available, has preferences
1
CPSC 322, Practice Exercise
Solutions to Variable Elimination
1
Directed Questions
What is a factor? Answer: A factor is a representation of a function from a tuple of random variables into a number. A factor f on variables X1 , .Xj is written as f (X1
1
CPSC 322, Practice Exercise
Solutions to Sequential Decisions
1
Directed Questions
How is a sequential decision problem dierent from a one-o decision problem? Answer:
In a one-o decision problem, even if there are multiple decisions to make they can be
1
CPSC 322, Practice Exercise
Solutions to Conditional Independence
1
Directed Questions
Describe the dierence between marginal independence and conditional independence.
Answer: For variables X and Y , if P (X|Y ) = P (X) then X is marginally independen
1
CPSC 322, Practice Exercise
Solutions to Heuristic Search
1
Directed Questions
What is the distinction between informed and uninformed search? Answer: Uninformed
search doesnt take into account any information about the goal (until the goal is reached)
1
CPSC 322, Practice Exercise
Solutions to Uninformed Search
1
Directed Questions
What is meant by search algorithm completeness? Answer: If an algorithm is complete,
it means that if at least one solution exists then the algorithm is guaranteed nd a sol
1
CPSC 322, Practice Exercise
Solutions to SLS for CSP
1
Directed Questions
In local search, how do we determine neighbours? Answer: A neighbour is usually just a
small incremental change to variable assignment. For example, a neighbour might be an
assig
1
CPSC 322, Practice Exercise
Solutions to STRIPS planning
1
Directed Questions
The STRIPS representation for an action consists of what?
Answer: Preconditions - a set of assignments of values to variables that must be true for
the action to occur. Eects
1
CPSC 322, Practice Exercise
Solutions to CSP planning
1
Directed Questions
What is meant by the horizon in a planning problem?
Answer: The number of time steps for which the problem is rolled out.
What are initial state constraints in a CSP problem?
A
1
CPSC 322, Practice Exercise
Solutions to Logic: Syntax
1
Directed Questions
In propositional denite clause logic (PDCL),
What is an atom? Give the denition and an example.
Answer: An atom is a symbol starting with a lower case letter.
Example: ai is f
1
CPSC 322, Practice Exercise
Solutions to Arc Consistency
1
Directed Questions
What does it mean for an arc to be consistent? Answer: An arc < X, r(X, Y ) > is arc
consistent if for each value x in dom(X) there is some value y in dom(y) such that r(x, y
1
CPSC 322, Practice Exercise
Solutions to Branch and Bound
1
Directed Questions
In branch and bound (B&B), how is the upper bound (UB) calculated? Answer: Its the
cost of the best solution found so far. If no solution has been found, the upper bound is