Brief introduction on Inference Engine in Expert System. Forward & Backward Chaining, KBS, KWS

1. Presented By:
Abhishek Pachisia - 090102801
Akansha Awasthi - 090102003
B.Tech – I.T.

2.  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.

3.  Computer program that tries to derive answers from
a knowledge base.
 Brain of Expert System
 Inference commonly proceeds by
 Forward chaining
 Backward chaining

4. ﴾ 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

5.  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.

6.  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.

7.  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

8. ¥ Forward chaining
¥ Backward chaining

9.  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.

10.  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.

11. It is a computer program to solve complex problems.
Reasons
Uses knowledge
Knowledge is acquired represented using various
knowledge representation
Techniques
Rules,
Frames and
Scripts.
User Inference Knowledge
Interface engine base

13. There are specialized systems for knowledge workers
To help them to create new knowledge
To ensure that this knowledge is properly integrated into the business
Critical Key roles of knowledge workers
Keeping the current knowledge
Serving as internal consultants regarding the areas of their knowledge
Acting as change agents
Knowledge work systems require strong links
To external knowledge bases in addition to specialized hardware and software.

14. 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

15. 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.

16. Investment workstations:
 These are high-end PCs used in the financial sector
 To analyze trading situations instantaneously and
 Facilitate portfolio management.