week 5 Flashcards
chp 5
Knowledge Representation (KR) definition, significance
The method of translating complex,
real-world information into a format that AI systems can utilize to
mimic “intelligent” behaviour.
Significance of KR
* Facilitates intelligent decision-making by providing the necessary information foundation.
* Acts as a precursor to reasoning—the ability of AI to make deductions and decisions.
Knowledge Reasoning
The process by which an AI system draws
new conclusions from stored knowledge. Involves logical deduction,
inferencing rules, and decision-making.
What to Represent:
-object, events, performance, meta-knowledge, facts, knowledge-base
- Object:All the facts about objects in our world domain. E.g., Guitars contains
strings, trumpets are brass instruments. - Events: Events are the actions which occur in our world.
- Performance: It describe behavior which involves knowledge about how to do
things. - Meta-knowledge: It is knowledge about what we know.
- Facts: Facts are the truths about the real world and what we represent.
- Knowledge-Base: The central component of the knowledge-based agents is the
knowledge base. It is represented as KB. The Knowledgebase is a group of the
Sentences (Here, sentences are used as a technical term and not identical with
the English language).
Type of knowledge: type 1 :declarative knowledge
- Declarative knowledge is to know about something.
- It includes concepts, facts, and objects.
- It is also called descriptive knowledge and expressed in declarative
sentences. - It is simpler than procedural language.
type of knowledge: Type 2: Procedural Knowledge
It is also known as imperative knowledge.
* Procedural knowledge is a type of knowledge that is responsible for
knowing how to do something.
* It can be directly applied to any task.
* It includes rules, strategies, procedures, agendas, etc.
* Procedural knowledge depends on the task on which it can be
applied.
Type 3: Meta-knowledge
- Knowledge about the other types of knowledge is called Meta-
knowledge.
type of knowledge : Type 4: Heuristic Knowledge
- Heuristic knowledge is representing knowledge of some experts in a
filed or subject. - Heuristic knowledge is rules of thumb based on previous experiences,
awareness of approaches, and which are good to work but not
guaranteed.
type of knowledge :Type 5: Structural Knowledge
- Structural knowledge is basic knowledge to problem-solving.
- It describes relationships between various concepts such as kind of,
part of, and grouping of something. - It describes the relationship that exists between concepts or objects.
AI Knowledge Cycle
- An Artificial intelligence
system has the following
components for displaying
intelligent behavior:
- Perception
- Learning
- Knowledge
Representation and
Reasoning - Planning
- Execution
Approaches to Knowledge Representation :(1. Simple relational knowledge:, 2. Inheritable knowledge:, )
- Simple relational knowledge:
* It is the simplest way of storing facts which uses the relational method, and
each fact about a set of the object is set out systematically in columns.
* This approach of knowledge representation is famous in database systems
where the relationship between different entities is represented.
* This approach has little opportunity for inference.
Approaches to Knowledge Representation
- Inheritable knowledge:
- Inheritable knowledge:
* In the inheritable knowledge approach, all data must be
stored into a hierarchy of classes.
* All classes should be arranged in a generalized form or a
hierarchal manner.
* In this approach, we apply inheritance property.
* Elements inherit values from other members of a class.
* This approach contains inheritable knowledge which shows
a relation between instance and class, and it is called
instance relation.
* Every individual frame can represent the collection of
attributes and its value.
* In this approach, objects and values are represented in
Boxed nodes.
* We use Arrows which point from objects to their values.
Approaches to Knowledge Representation
- Inferential knowledge:
- Inferential knowledge:
* Inferential knowledge approach represents knowledge in the form of formal
logics.
* This approach can be used to derive more facts.
* It guaranteed correctness.
* Example: Let’s suppose there are two statements:
* Marcus is a man
* All men are mortal
* Then it can represent as;
man(Marcus)
∀x = man (x) ———-> mortal (x)
Approaches to Knowledge Representation
- Procedural knowledge:
Procedural knowledge approach uses small programs and codes which
describes how to do specific things, and how to proceed.
* In this approach, one important rule is used which is If-Then rule.
* In this knowledge, we can use various coding languages such as LISP language
and Prolog language.
* We can easily represent heuristic or domain-specific knowledge using this
approach.
* But it is not necessary that we can represent all cases in this approach.
Techniques of Knowledge Representation( Logical Representation)
- Logical Representation
- Syntax
- Syntaxes are the rules that decide how we can construct legal sentences in
the logic. - It determines which symbol we can use in knowledge representation.
- How to write those symbols.
- Semantics
- Semantics are the rules by which we can interpret the sentence in the logic.
- Semantic also involves assigning a meaning to each sentence.
- Logical representation can be categorized into mainly two logics:
- Propositional Logics
- Predicate logics
Techniques of Knowledge Representation (Semantic Networks)
- Semantic Networks
- This representation consists of mainly two types of relations:
- IS-A relation (Inheritance)
- Kind-of-relation
- Example: The following are some statements that we need to
represent in the form of nodes and arcs. - Statements:
Jerry is a cat.
Jerry is a mammal
Jerry is owned by Priya.
Jerry is brown colored.
All Mammals are animal.