Module 5

Question 1

What are knowledge based agents

Answer 1

Use process of reasoning to decide actions

Question 2

What is a knowledge base

Answer 2

Set of sentences in formal language

Question 3

What’s is the declarative approach to build KB agent

Answer 3

Tell what it needs to know
Ask itself what to do from KB
Operations involve inference

Question 4

Can single inference algorithm answer any solvable question

Answer 4

Yes

Question 5

What is inference engine and KB

Answer 5

KB - domain specific facts

Inference engine - generic code

Question 6

Describe the KB agent flow

Answer 6

Given percept, agent adds percept to KB and asks KB for best action, it communicates KB that it took action

Question 7

List types of KB agents

Answer 7

Declarative - build KB by telling it what it needs to know

Procedural - Encode desired behaviours as program code

Question 8

How do agents acquire knowledge

Answer 8

Through percept - (transition model and sensor model)

Can keep track of partially observable world

Question 9

What is syntax

Answer 9

What sentences are allowed, defines well formed sentences

Question 10

What is semantics

Answer 10

Meaning of sentence linked to the world, where it’s true / false

Question 11

What is entailment

Answer 11

One thing logically follows another

Question 12

When does KB entail a

Answer 12

Iff a is true in all worlds where KB is true

Question 13

What is a model

Answer 13

M is a model of a sentence a if a is true in m

Question 14

What is M (a)

Answer 14

The set of all models of a

Question 15

What is inference

Answer 15

Allows new sentences to be derived from KB

Question 16

Inference notation

Answer 16

KB |-I a

Question 17

What does KB |-I a mean

Answer 17

Sentence a can be derived from KB by using inference I

Question 18

What is the soundness of inference

Answer 18

Everything probable is true, no false positives, derived entailed sentences. KB |-i a true then KB |= a is true

Question 19

What is the completeness of inference

Answer 19

Everything true is possible, no false negatives. KB |= a true then KB |-I a is true

Question 20

KB transference into real world

Answer 20

If KB is true in real world, then any sentence a derived from KB by a sound inference is also true in real world

Question 21

Types of inference proofs

Answer 21

Model checking - for every possible world, if a is true make sure b true aswell

Theorem proving - search for a sequence of proof steps leading from a to b

Question 22

List the types of logic

Answer 22

Propositional
First order logic
Relational db

Question 23

What is propositions calculus and what does proposition help with

Answer 23

Proposition helps with inference and and propositional calculus is language of propzrisitons

Question 24

What is a well formed formula

Answer 24

An atom.

Question 25

What does PL deal with

Answer 25

Validate and unsatisfiability of a formula and derivation of new formulas

Question 26

What is a tautology

Answer 26

Iff a is true in all interpretations

Question 27

When is a formula valid

Answer 27

Valid iff tautology

Question 28

When is formula consistent

Answer 28

If at least one interpretation true

Question 29

When is formula inconsistent/unsatisfiable?

Answer 29

Iff a is always false in all interpretations

Question 30

Truth table pros and cons

Answer 30

Pros - good for small number of clauses and good at representing survey
Cons - n atoms lead to 2^n entries, all entries may not be relevant

Question 31

Reasoning pattern for inference

Answer 31

And elimination
Modus pones
De Morgan’s law
Monotonic, sound but not complete

Question 32

Resolution refutation

Answer 32

Negation of goal is proved by showing empty set.

Question 33

Conjunctive normal form

Answer 33

( V V V ) /\ ( V V V)

Question 34

Conversion to CNF

Answer 34

eliminate -> and
Eliminate ~~
Use de Morgan
Use distributive

Question 35

If two clauses contains complementary literals

Answer 35

Can be resolved

New clauses is resolvent to parent clauses

Question 36

Another name for resolvent

Answer 36

Logical consequence