CMSC 471 - Midterm

What are the main points/conditions for Alpha-beta pruning?

"a" initialized to -∞ "b" initialized to ∞ "a" updated at max nodes "b" updated at min nodes Prune condition: If a >= b at anytime, then prune the remaining branches/nodes below and/or to the right of the current node

Rules for Converting to CNF

1) <=>: a<=>b --> (a =>b) && (b =>a) 2) =>: a => b --> ~a || ~b 3) ~ (negation): move negation inwardds using de Morgan's rule (if applicable) 4) Distribute || over && (i.e [A || (B && C)] = [(A || B) && (A || C)] 5) Flatten by removing excess parentheses

Which statement is true about k-consistency? Select all that apply. 1-consistency is the same as arc consistency 2-consistency is the same as node consistency 3-consistency is the same as path consistency for binary constraint graphs. A CSP with 3 nodes is strongly 3-consistent if it is arc-consistent and node-consistent

3-consistency is the same as path consistency for binary constraint graphs.

Which of the following statements is true. Select all that apply. A* search uses this evaluation function: f(n) = h(n) + g(n) Greedy best first search uses this evaluation function f(n) = g(n) -h(n) g(n) is the estimated cost to reach the goal h(n) is the cost to reach the current node from the start node

A* search uses this evaluation function: f(n) = h(n) + g(n)

Which statement about backtracking is true? Select all that apply. A) Backtracking has inefficiency issue because it may explore areas of the search space that aren't likely to succeed. B) Minimum Remaining Values (MRV), Most Constraining Variable and Least Constraining Value are among the heuristics used to improve backtracking solver. C) Backtracking uses BFS D) Backtracking guarantees to find a solution for CSP

A, B A) Backtracking has inefficiency issue because it may explore areas of the search space that aren't likely to succeed. B) Minimum Remaining Values (MRV), Most Constraining Variable and Least Constraining Value are among the heuristics used to improve backtracking solver.

Which of the following search strategies uses heuristics. Select all that apply. A) A* B) Greedy Best First Search C) Breadth First Search (BFS) D) Uniform Cost Search

A,B A) A* B) Greedy Best First Search

What are the assumptions about adversarial search? Select all that apply. A) Perfect information, i.e. both players have access to complete information about the states. B )Zero-sum , i.e. the utility values for both players at the end of the game are equal and opposite, e.g. +1 and -1 C) The utility values at the end of the game for both players are equal e.g they're both +1 D) There is only one single agent who searches the state space of the game

A,B A) Perfect information, i.e. both players have access to complete information about the states. B )Zero-sum , i.e. the utility values for both players at the end of the game are equal and opposite, e.g. +1 and -1

What statement characterizes the relationship and the difference between Agent Function and Agent Program correctly? Select all that apply. A) Agent program is a concrete implementation and takes the current percept as input whereas agent function is an abstract mathematical description and may depend on the entire percept history. B) Tabular description of any given rational agent is the agent function. C) Agent function can be constructed by trying out all possible percept sequences and recording which actions the agent does in response. D) Agent function is internal characterization of the agent

A,B,C A) Agent program is a concrete implementation and takes the current percept as input whereas agent function is an abstract mathematical description and may depend on the entire percept history. B) Tabular description of any given rational agent is the agent function. C) Agent function can be constructed by trying out all possible percept sequences and recording which actions the agent does in response.

What are the limitations of game search algorithms? Select all that apply. A) Alpha-beta search is vulnerable to errors in the heuristic function. B) Both alpha-beta and MCTS are designed to evaluate the values of legal moves, and this sometimes may not be efficient when there is one move that is obviously best. C) Both alpha-beta ad MCTS do all the reasoning at their level of individual moves. D) Early game programs relied on human expertise to hand-craft evaluation functions.

A,B,C,D A) Alpha-beta search is vulnerable to errors in the heuristic function. B) Both alpha-beta and MCTS are designed to evaluate the values of legal moves, and this sometimes may not be efficient when there is one move that is obviously best. C) Both alpha-beta ad MCTS do all the reasoning at their level of individual moves. D) Early game programs relied on human expertise to hand-craft evaluation functions.

Which of the following properties may apply to the chess game environment? Select all that apply. A) Fully observable B) Deterministic C) Sequential D) Discrete

A,B,C,D A) Fully observable B) Deterministic C) Sequential D) Discrete

Which of the following statements is true about Online Search? Select all that apply: A) Online search is a good idea in dynamic or semidynamic domains. B) Online search is helpful in nondeterministic domains. C) Online search is a necessary idea for unknown environments. D) In Learning Real-time A* (LRTA*) heuristic is updated as the agent gains experience in the state space.

A,B,C,D A) Online search is a good idea in dynamic or semidynamic domains. B) Online search is helpful in nondeterministic domains. C) Online search is a necessary idea for unknown environments. D) In Learning Real-time A* (LRTA*) heuristic is updated as the agent gains experience in the state space.

What statements are true about soundness and completeness? Select all that apply. A) Soundness means derivations produce only entailed sentences. B) Completeness means derivations can produce all entailed sentences. C) Resolution is sound and complete for propositional logic. D) Forward chaining is sound and complete.

A,B,C,D A) Soundness means derivations produce only entailed sentences. B) Completeness means derivations can produce all entailed sentences. C) Resolution is sound and complete for propositional logic. D) Forward chaining is sound and complete.

Which of the following statements is true? Select all that apply. A) Hill climbing may get stuck in local maximum. B) Hill climbing may get stuck in plateau - flat area. C) Random restart is one way to overcome hill climbing failure. D) Hill climbing sometimes allows for bad moves, e.g going to a lower state

A,B,C: A) Hill climbing may get stuck in local maximum. B) Hill climbing may get stuck in plateau - flat area. C) Random restart is one way to overcome hill climbing failure.

What are the possible ways of Cognitive Modeling approach? Select all that apply. A) Introspection B) Psychological Experiments C) Brain Imaging D) Computer Vision

A,B,C: A) Introspection B) Psychological Experiments C) Brain Imaging

Which statement about alpha-beta pruning is correct? Select all that apply. A) The effectiveness of alpha-beta pruning is highly dependent on the order in which the states are examined. B) Alpha-beta pruning algorithm keeps track of alpha and beta values for the nodes that it visits and uses them to prune the search tree. C) At any visited node, if alpha or beta gets updated such that alpha <= beta, then we prune the rest of the children of that node from the search tree D) Alpha is updated at Max nodes and beta is updated at Min nodes.

A,B,D A) The effectiveness of alpha-beta pruning is highly dependent on the order in which the states are examined. B) Alpha-beta pruning algorithm keeps track of alpha and beta values for the nodes that it visits and uses them to prune the search tree. D) Alpha is updated at Max nodes and beta is updated at Min nodes.

Which statement is true about the structure of CSP? Select all that apply. A) Any tree-structured CSP can be solved in time linear in the number of variables. B) In cutset conditioning, the cycle cutset is removed from CSP such that the constraint graph becomes a tree. C) In tree decomposition, some variables of the original problem may not appear in the tree nodes D) In tree decomposition, if a variable appears in two nodes in the tree, it must appear in every node along the path connecting those nodes.

A,B,D: A) Any tree-structured CSP can be solved in time linear in the number of variables. B) In cutset conditioning, the cycle cutset is removed from CSP such that the constraint graph becomes a tree. D) In tree decomposition, if a variable appears in two nodes in the tree, it must appear in every node along the path connecting those nodes.

Which of the following statements is true? Select all that apply. A) BFS is complete if the branching factor b is finite. B) In state spaces with cyclic path, DFS is not complete even if the branching factor b and the depth d are finite. C) BFS is NOT complete if the branching factor b is fintie D) One motivation for using DFS is its linear space complexity.

A,B,D: A) BFS is complete if the branching factor b is finite. B) In state spaces with cyclic path, DFS is not complete even if the branching factor b and the depth d are finite. D) One motivation for using DFS is its linear space complexity.

Which of the following statements is true? Select all that apply. A) Space complexity of DFS is O(bm) where b is the branching factor and m is the maximum depth of the search tree. B) Space complexity of DFS is LOWER than BFS. C) Space complexity of DFS is HIGHER than BFS. D) Depth-first tree search needs to store only a single path from the root to a leaf node, along with the remaining unexpected sibling nodes for each node on the path, and that is why DFS has a lower space complexity than BFS.

A,B,D: A) Space complexity of DFS is O(bm) where b is the branching factor and m is the maximum depth of the search tree. B) Space complexity of DFS is LOWER than BFS. D) Depth-first tree search needs to store only a single path from the root to a leaf node, along with the remaining unexpected sibling nodes for each node on the path, and that is why DFS has a lower space complexity than BFS.

If h1 and h2 are both admissible heuristics, which of the following heuristics are guaranteed to be admissible. Select all that apply. A) max(h1,h2) B) min(h1,h2) C) h1+h2 D) h1 * h2

A,B: max(h1,h2) min(h1,h2)

What are the major weaknesses of heuristic-based alpha-beta tree search? Select all that apply. A) Alpha-beta tree search is sometimes limited to only a few ply. B) Alpha beta tree search does not use evaluation functions C) Sometimes it is difficult to find a good evaluation function for alpha-beta tree search. D) Alpha-beta tree search is uniformed

A,C A) Alpha-beta tree search is sometimes limited to only a few ply. C) Sometimes it is difficult to find a good evaluation function for alpha-beta tree search.

Which statement is true about Depth-limited search? Select all that apply. A) Depth-limited search is complete if l >= d (l greater than or equal to d) where l is limit and d𝑑 is the depth of the shallowest solution. B) Depth-limited search is optimal if l ≠ d where l is limit and d𝑑 is the depth of the shallowest solution. C) Depth-limited search is optimal if l = d where l is limit and d𝑑 is the depth of the shallowest solution.

A,C A) Depth-limited search is complete if l >= d (l greater than or equal to d) where l is limit and d𝑑 is the depth of the shallowest solution. C) Depth-limited search is optimal if l = d where l is limit and d𝑑 is the depth of the shallowest solution.

Which of the following statements are true about gorilla problem? Select all that apply. A) Gorilla problem may lead to the idea to stop AI. B) Gorilla problem indicates that we should expedite the development of Artificial Superintelligence (ASI). C) Artificial SuperIntelligence (ASI) raised widespread concerns about the future of AI. D) Turing raised similar concerns as gorilla problem.

A,C,D A) Gorilla problem may lead to the idea to stop AI. C) Artificial SuperIntelligence (ASI) raised widespread concerns about the future of AI. D) Turing raised similar concerns as gorilla problem.

Which of the following statements are true in the context of state representation? Select all that apply. A) In an atomic representation, each state of the world is indivisible - it has no internal structure. B) In an atomic representation, each state of the world can be split to a fixed set of variables or attributes C) In a factored representation, each state of the world can be split to a fixed set of variables or attributes. D) Search algorithms like BFS and DFS work with atomic representations.

A,C,D A) In an atomic representation, each state of the world is indivisible - it has no internal structure. C) In a factored representation, each state of the world can be split to a fixed set of variables or attributes. D) Search algorithms like BFS and DFS work with atomic representations.

What is the goal of Gradient Descent algorithm? Select all that apply. A) Finding the global optima B) Finding a local minima C) Optimizing the cost function D) Finding a local maxima

A,C: A) Finding the global optima C) Optimizing the cost function

Which of the following statements is true? Select all that apply: A) Simulated annealing sometimes allows for bad moves based on a probability that decreases over time. B) Simulated annealing sometimes allows for bad moves based on a probability that increases over time. C) Simulated annealing does not allow bad moves, it always strives for good moves D) The temperature T decreases over time (cools down) to reduce the probability of bad moves by simulated annealing.

A,D A) Simulated annealing sometimes allows for bad moves based on a probability that decreases over time. D) The temperature T decreases over time (cools down) to reduce the probability of bad moves by simulated annealing.

Which of the following is NOT an agent type, but rather a way of state representation? Simple reflex Atomic Goal-based Utility-based

Atomic

Which of the following statements is true? Select all that apply. A) Admissibility is a stronger condition than consistency B) Consistency is a stronger condition than admissibility. C) Every consistent heuristic is also admissible. D) Every admissible heuristic is also consistent

B,C B) Consistency is a stronger condition than admissibility. C) Every consistent heuristic is also admissible.

Which statement regarding CSP solution is true? Select all that apply. A) A complete assignment means all constraints are satisfied B) An assignment that does not violate any constraints is called a consistent or legal assignment. C) A solution must be a complete and consistent assignment. D) A partial assignment is one that assigns values to only some of the variables.

B,C,D B) An assignment that does not violate any constraints is called a consistent or legal assignment. C) A solution must be a complete and consistent assignment. D) A partial assignment is one that assigns values to only some of the variables.

What statement is true about Deep Learning? Select all that apply A) Any ML approach is also considered as Deep Learning B) Any Deep Learning algorithm is also considered as Machine Learning. C) Deep Learning uses multiple layers of Neural Networks aka Deep Networks. D) Deep Learning relies heavily on BOTH powerful hardware and the availability of large amounts of training data.

B,C,D: B) Any Deep Learning algorithm is also considered as Machine Learning. C) Deep Learning uses multiple layers of Neural Networks aka Deep Networks. D) Deep Learning relies heavily on BOTH powerful hardware and the availability of large amounts of training data.

Which statement is true about stochastic games? Select all that apply. A) Expectiminimax value is the dot product of the weight vector and feature vector B) Expectiminimax value is the weighted sum of the value over all outcomes weighted by the probability of each chance action. C) Expectiminimax value is a generalization of the minimax value to incorporate uncertainty. D) Chance nodes represent the probabilities of each outcome.

B,C,D: B) Expectiminimax value is the weighted sum of the value over all outcomes weighted by the probability of each chance action. C) Expectiminimax value is a generalization of the minimax value to incorporate uncertainty. D) Chance nodes represent the probabilities of each outcome.

Which statement is true about Beam Search? Select all that apply Beam Search Spreads out everywhere in concentric search contours and explores the whole nodes within a contour Beam search removes k nodes with the worst f-scores The solution of Beam Search is optimal Beam search generally uses less memory than A*

Beam Search generally uses less memory than A*.

Which statement about backtracking heuristics is true? Select all that apply. A) "Least constrained value" chooses the variable with minimum number of constraints B) "Minimum Remaining Value (MRV)" chooses the remaining values that are in the minimum of the domain C) "Most Constraining Variable" chooses the variable involved in largest number of constraints on remaining variables. D) Using forward checking heuristic may detect failure of a path earlier.

C,D C) "Most Constraining Variable" chooses the variable involved in largest number of constraints on remaining variables. D) Using forward checking heuristic may detect failure of a path earlier.

Which one is the best example of "Thinking Humanly" approach in AI? Cognitive Modeling in Cognitive Science Turing Test Bio-Inspired AI Computer Vision

Cognitive Modeling in Cognitive Science

The Minimax algorithm uses a strategy for search similar to: BFS DFS A* Uniform Cost Search

DFS

What is the search algorithm that is used in the backtracking solver? BFS DFS Iterative Deepening Search Uniform cost search

DFS

Horn Clause

Disjunction of literals which at most one literal is positive

Methods that measure progress by the change in the value of the objective function between two nearby points are called _____________ methods. Constrained optimization Informed search Offline Search Empirical gradient

Empirical gradient

What type of state representation is used in CSP? Atomic Factored Structured Invisible

Factored

True of False: You can use adversarial search in a single-player puzzle game such as Sudoku, or Rubik's cube.

False

True or False: A* search and Greedy best-first search both use the same evaluation function f(n).

False

True or False: Alpha is updated by taking the minimum of the current value and the new value.

False

True or False: Gradient descent is an optimization algorithm but is never used in Machine Learning due to its problems.

False

True or False: Greedy Best First Search guarantees both completeness and optimality.

False

True or False: In Alpha-beta pruning algorithm, you initialize Alpha with +∞ and Beta with -∞.

False

True or False: Local maximum is a point where no other point in the entire search space may have a higher objective function than that.

False

True or False: Satisficing solutions are optimal solutions.

False

True or False: The space complexity of DFS is O(b^m) - b to the power of m - where b is branching factor and m is the maximum depth of the search tree.

False

Ture or False: Unary constraint restricts the value of two variables.

False

True or False: "Unknown" IS an assumption about the search environment?

False "Unknown" is NOT an assumption about the search environment (Quiz #2 Q6)

Which of the following is NOT a task environment property? Fully observable vs partially observable Episodic vs sequential Single agent vs multi agent Goal based vs utility based

Goal-based vs utility-based

Goal Clause

Horn clause with no positive literals

Admissible Heuristic Function

Never overestimates the cost fo the minimum cost path to goal must be admissible for all states always optimistic To prove a heuristic is admissible, show that the inequality holds for all values

Deduction Theorem:

P |= Q iff P => Q is true

Which of the following properties may apply to the chess environment? Select all that apply. Partially Observable Stochastic Continuous Sequential

Sequential

Entailment

Symbol: |= Definition: one thing follows from another Ex: kB |= a => kB entails "a" iff "a" is true everywhere kB is true Ex: x+y=4 entails 4=x+y

True of False: Comparing AI, Machine Learning, and Deep Learning, one can argue that there is a superset-subset relationship between them such that Deep Learning is a subset of Machine Learning approaches, and Machine Learning is a subset of the broad field of approaches, algorithms and techniques in AI.

True

True or False: A* usually runs out of space long before it runs out of time. For this reason, A* may not be practical for very large-scale problems.

True

True or False: An admissible heuristic never overestimates the true cost of getting from a state to the goal state.

True

True or False: BFS and DFS are both uninformed search.

True

True or False: Backtracking algorithm is a CSP solver.

True

True or False: Evaluation function is the dot product of weight vector and feature vector.

True

True or False: IDA*, Recursive Best First Search (RBFS) and SMA* are memory-bounded heuristic searches that try to overcome the issue with A* space complexity - high memory usage.

True

True or False: In Genetic Algorithm, each location in the offspring (after crossover) is subject to random mutation with a small independent probability.

True

True or False: Intelligence is concerned with rational action.

True

True or False: Iterative deepening DFS combines the benefits of DFS and BFS. Its space complexity is O(bm) like DFS and it is complete like BFS if the branching factor is finite.

True

True or False: Local beam search can suffer from a lack of diversity among the k states.

True

True or False: Rationality is NOT omniscience. Omniscience is usually impossible in reality.

True

True or False: Selection, crossover and mutation are all random processes.

True

True or False: Space complexity deals with memory only.

True

True or False: The cost of an optimal solution to a relaxed problem is an admissible heuristic for the original problem.

True

True or False: The term percept refers to the agent's perceptual inputs at any given instant.

True

True or False: The time complexity of BFS is O(b^d) where b is branching factor and d is the depth of the shallowest solution.

True

True or False: The tree-search version of A* is optimal if h(n) is admissible, while the graph-search version is optimal if h(n) is consistent.

True

True or False: When a CSP is not arc consistent, we may make it arc consistent by using the AC3 algorithm with no guarantee for all problems.

True

Ture or False: Forward checking keeps track of remaining legal values for the unassigned variables.

True

Ture or False: The interdisciplinary field of Cognitive Science brings together computer models from AI and experimental techniques from psychology to construct precise and testable theories of the human mind.

True

Which one is the best example of "Acting Humanly" approach in AI? Turing Test Reinforcement Learning Bio-Inspired AI Cognitive Science

Turing Test

What statement about the weight W of heuristic h is true? Select all that apply. W of A* is greater than 1: W > 1 W of uniform cost search is infinity: W = ∞ W of Greedy Best First Search (BGFS) is zero: W = 0 W of weighted A* is greater than 1: 1 < W < ∞

W of weighted A* is greater than 1: 1 < W < ∞

Definite Clause

disjunction of literals where exactly one literals is positive

True or False: i) Frontier is the set of states (nodes) that have been reached but not yet expanded ii) Frontier separates two regions of the state-space graph: an interior region where every state has been expanded; and an exterior region of states that have not yet been reached.

i) True ii) True