Department of Computing
Faculty of Engineering, Science and Technology (FEST)
Indus University, Karachi
ASSIGNMENT NO: 4
Formal Method
Name: Muhammad Fahad
Students I.D: 425-2019
Subject: Formal Method
Date of submission: ____________
Submitted to: Sir Ramzan
Teachers Sig:____________
Q 1. Rule-based systems (RBS)
RULE-BASED SYSTEM
The term "rule-based system" refers to systems that have rule sets that have been handcrafted or
curated by humans. This system type usually excludes rule-based systems that use automatic rule
inference, such as rule-based machine learning.
A rule-based system is used in computer science to store and manipulate knowledge in order to
understand data in un usable way. It's frequently utilized in artificial intelligence research and
applications.
Q 2. Components of Rule-based systems
COMPONENTS
A typical rule-based system has four basic components:[3]
1. A list of rules or rule base, which is a specific type of knowledge base.
2.
Based on the interplay of input and the rule base, an inference engine or semantic reasoner
infers knowledge or takes action. The following match-resolve-act cycle is used by the
interpreter to run a production system program.

Match: In this first phase, the left-hand sides of all productions are matched against the
contents of working memory. As a result a conflict set is obtained, which consists of
instantiations of all satisfied productions. An instantiation of a production is an ordered
list of working memory elements that satisfies the left-hand side of the production.

Conflict-Resolution: In this second phase, one of the production instantiations in the
conflict set is chosen for execution. If no productions are satisfied, the interpreter halts.

Act: In this third phase, the actions of the production selected in the conflict-resolution
phase are executed. These actions may change the contents of working memory. At the
end of this phase, execution returns to the first phase.
3. Temporary working memory.
4. A user interface or other connection to the outside world through which input and output
signals are received and sent.