Page 168 - DCAP310_INTRODUCTION_TO_ARTIFICIAL_INTELLIGENCE_AND_EXPERT_SYSTEMS

Introduction to Artificial Intelligence & Expert Systems

Notes blocks of applications from an object-oriented perspective. Each different type of object comes
from a specific class of that type. A class is a blueprint or template or set of instructions to build
a specific type of object. Every object is built from a class. Each class should be designed and
programmed to accomplish one, and only one, thing. (You’ll learn more about the Single
Responsibility Principle in Object-oriented programming concepts: Writing classes.) Because
each class is designed to have only a single responsibility, many classes are used to build an
entire application. An instance is a specific object built from a specific class. It is assigned to a
reference variable that is used to access all of the instance’s properties and methods. When you
make a new instance the process is called instantiation and is typically done using the new
keyword. Think about classes, instances, and instantiation like baking a cake.
A class is like a recipe for chocolate cake. The recipe itself is not a cake. You can’t eat the recipe
(or at least wouldn’t want to). If you correctly do what the recipe tells you to do (instantiate it)
then you have an edible cake. That edible cake is an instance of the chocolate cake class. We can
bake as many cakes as you would like using the same chocolate cake recipe. Likewise, you can
instantiate as many instances of a class as you would like. Pretend you are baking three cakes for
three friends who all have the same birthday but are different ages. You will need some way to
keep track of which cake is for which friend so you can put on the correct number of candles. A
simple solution is to write each friend’s name on the cake. Reference variables work in a similar
fashion. A reference variable provides a unique name for each instance of a class. In order to
work with a particular instance, you use the reference variable it is assigned to.

!
Caution Learn the basic concepts of OOPs before implementing it.

Task Make a Java program for small calculator using objects and classes.

Self Assessment

State whether the following statements are true or false:
15. Every object is built from a class.

16. Objects are the fundamental building blocks of applications from an object-oriented
perspective.

8.9 Summary

The Hopfield is an auto-associative network often used (or derivatives of it) in monochrome
image recognition.
A script is a data structure used to represent a sequence of events. Scripts are used for
interpreting stories. Popular examples have been script driven systems that can interpret
and extract facts from Newspaper Stories.

The object-oriented approach to programming is based on an intuitive correspondence
between a software simulation of a physical system and the physical system itself.
Frame is a type of schema used in many AI applications including vision and natural
language processing. Frames provide a convenient structure for representing objects that
are typical to stereotypical situations.

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