Page 31 - DCAP310_INTRODUCTION_TO_ARTIFICIAL_INTELLIGENCE_AND_EXPERT_SYSTEMS

Unit 2: Knowledge

5. Use the symbol processing approach. Notes
6. Ability to explain its own reasoning.
The KBS can help acting as intelligent assistants to human experts or, in certain cases, even
replacing the human experts.

2.3.2 Structure of a Knowledge-based System

There are three principle roles for those who work with KBS:
(i) End user: Doctor, factory manager, person of the street, etc.
(ii) Knowledge Engineer: The person who designs, classifies, organizes, builds a representation
of the knowledge)
(iii) Constructor of the Tools for the KBS: Typically a programmer
The major components of an Expert System are high level Knowledge-base, Inference Engine
and User Interface.
Knowledge-base: An expert system can give intelligent answers to sufficient knowledge about
the field. The component of the ‘expert system’ that contains the system’s knowledge is called
the knowledge-base. It is a vital component of KBS. The knowledge-base consists of the
declarative knowledge and procedural knowledge.

Declarative knowledge consists of facts about objects, events and situations. Procedural knowledge
consists of courses of action. Knowledge representation is a process of putting the knowledge
into the systems knowledge-base in the form of facts by using the above two types while KBS
uses reasoning to draw the conclusions from stored facts.

Inference Engine: If the system has knowledge, it must be capable of using the knowledge in
appropriate manner. Systems must know how and when to apply the knowledge, i.e. Inference
Engine works as a control programmed to decide the direction of the search in KBS.

The KBS uses different types of search techniques to find the solutions of given problems. Search
is the name given to the process of shifting through alternative solutions to reach the Goal state.
The search is carried through search space. Problem is moved from Initial State to Goal State
through state space. The Inference Engine ‘decides’ which heuristic search techniques are used to
determine and how the rules in the knowledge-base are to be applied to the problem. Inference
Engine is independent of the knowledge-base.
User Interface: User must have communicated with the system. KBS helps its user to communicate
with it is known as ‘user interface’ in form of bi-directional communication. The system should
be able to ask much information to arrive at a solution or the user want to know the reasoning
about the facts. Thus, it is important to have a user interface that can be used by common people.

2.3.3 KBS Development

The development of a KBS may require a team of several people working together.

There are two types of people involved in the development of the expert system.
1. Domain Experts: Domain Experts provide the information for the Knowledge-base.
2. Knowledge Engineers: Knowledge Engineer develops the Knowledge-based System.

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