2. AGENDA
• Knowledge Representation Schemes
• Slot &Filter Structure
• What is Frame?
• Classes and Instances
• Semantic Representation using Frames
• Advantages and Disadvantages of frames
4. SLOT & FILTER STRUCTURE
• It is divided into two types
1. Weak Slot and Filter Structure
2. Strong Slot and Filter Structure
Weak Slot and Filter Structure
• The knowledge in slot and filter systems consists of structures as a set of entities
and their attributes. That are represented by Semantic nets and Frames
5. SLOT & FILTER STRUCTURE
Strong slot and filter Structure
• It represents links between objects according to more rigid rules. That are
represented by Scripts and conceptual Dependency.
6. WHAT IS FRAME?
• To represent natural language we require assumptions about what is typically true of the
objects or situations under consideration, such information into structures known as
frames.
• Frame is a collection of attributes or slots and associated values that describe some real
world-entity.
• Frames uses data structures(records)to represent the knowledge in Semantic N/W.
• Each frame represents the node in semantic N/w as class, or an instance and each relation
as slot.
• Ex. Slot Filter
Publisher THH
Title AI
7. INFORMATION INCLUDED IN A SLOT
• Frame name
• Relationship of the frame to the other frames. The frame IBM Aptiva S35 might be
a member of the class Computer, which in turn might belong to the class
Hardware.
• Slot value .A
• Slot value can be symbolic ,numeric or Boolean. For example, the slot Name has
symbolic values and the slot Age has Numeric value.
• Slot values can be assigned when the frame is created or during a session with
the expert system.
8. INFORMATION INCLUDED IN A SLOT
• Default slot value. The default value is taken to be true when no evidence to the
contrary has been found. For example,a car frame might have four wheels and a
chair frame have four legs as default values in the corresponding slots.
• Range of the slot value .The range of the slot value determines whether a
particular object or concept observes the requirements defined by the frame.
• For example, the cost of the computer might be specified between $750 and
$1500.
9. FRAMES AS SETS AND INSTANCES
• The set theory is a good basis for understanding frames systems.
• Each frame represents either a class(set) or an instance .
• Both is a and instance relations have inverse attributes, which we call subclasses &all
instances.
• As a class represents a set, there are 2 kinds of attributes that can be associated with
it.
• Its own attributes &
• Attributes that are to be inherited by each element of the set.
• A class-frame describes a group of objects with common attributes. Animal, person,
car and computer are all class-frames, and instance-frame is referring to a particular
object.
• Each instance-frame in a frame-based system ‘knows’ its class.
11. SEMANTIC NETWORK REPRESNTATION IN FRAMES
• A node in Semantic network is represented as an entity or class and each relation as slot
In the frame.
• A semantic network can be represented in the form of frame as
Science Faculty
Faculty Department
Aman
Is-a
12. ADVANTAGES AND DISADVANTAGES OF FRAMES
• The frame knowledge representation makes the programming easier by grouping the
related data.
• The frame representation is comparably flexible and used by many applications in AI.
• It is very easy to add slots for new attribute and relations.
• It is easy to include default data and to search for mising values.
• Frame representation is easy to understand and visualize.
• Disadvantages.
• Frame representation has a much generalised approach.
