Inference Engine

Presented By:

Abhishek Pachisia - 090102801

Akansha Awasthi - 090102003

B.Tech – I.T.

Foreword - Expert System An Expert system is a computer system that emulates the

decision-making ability of a human expert

 It is divided into two parts, Fixed, Independent : The Inference Engine, Variable: The Knowledge Base

Engine reasons about the

knowledge base like a human.

Foreword - Inference Engine Computer program that tries to derive answers from

a knowledge base.

Brain of Expert System

Inference commonly proceeds by  Forward chaining Backward chaining

﴾ Grandfather (Tom -Marry) ﴾ Father (Tom -Jack) ﴾ Father (Jack -Mary)

Here there are two facts₪ Tom is the father of Jack₪ Jack is the father of Mary

Example

An interpreter The interpreter executes the chosen agenda items by applying

the corresponding base rules.

A scheduler The scheduler maintains control over the agenda by estimating

the effects of applying inference rules in light of item priorities or other criteria on the agenda.

A consistency enforcer The consistency enforcer attempts to maintain a consistent

representation of the emerging solution.

Inference Engine Components

Conflict resolution If there are activations then select the one with the highest

priority else done

Act Sequentially Perform the actions. Update the working memory. Remove the fired activations.

Operation Cycle - I

Match Update the agenda - Checking if there are activations if their

LHS is no longer satisfied.

Check for halt - Two commands tell that action is over. Break Halt

Operation Cycle - II

¥ Forward chaining

¥ Backward chaining

Inference Methods

Takes rule and if its conditions are true adds its conclusion to working memory until no more rules can be applied

If the conditions of the rule if A and B then C are true then C is added to working memory.

In forward chaining the system simply test the rules in the order that occurs therefore rule order is important.

Forward Chaining

The backward chaining inference engines tries to prove a goal by establishing the truth of its conditions

The rule if A and B then C the backward chaining engine will try to prove C by first proving A and then proving B. Proving these conditions to be true may well invoke further calls to the engine and so on.

Backward Chaining

It is a computer program to solve complex problems. ReasonsUses knowledge

Knowledge is acquired represented using various knowledge representation Techniques Rules, Frames and Scripts. 

Knowledge Based System

UserInterface

Inference

engine

Knowledge

base

Knowledge Based System

There are specialized systems for knowledge workers To help them to create new knowledgeTo ensure that this knowledge is properly integrated into the business

Critical Key roles of knowledge workersKeeping the current knowledgeServing as internal consultants regarding the areas of their knowledgeActing as change agents

Knowledge work systems require strong links To external knowledge bases in addition to specialized hardware and software.

Knowledge Work System

CAD/CAM systems:  Computer-aided design (CAD) and Computer-aided

manufacturing (CAM) systems automate The creation and Revision of designs,

using computers and sophisticated graphics software. They provide

Engineers, Designers, and Factory managers

with precise manufacturing control over industrial design and

manufacturing

KWS - Examples

Virtual reality systems:  These use interactive graphics software to

Aid drug designers, Architects, Engineers, and Medical workers

by presenting precise, three-dimensional simulations of objects.

KWS - Examples

Investment workstations:  These are high-end PCs used in the financial sector

To analyze trading situations instantaneously and Facilitate portfolio management.

KWS - Examples

That’s All

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