Reasoning Systems
1. Reasoning Systems
If-then rules have become the most popular form of declarative knowledge representation used in artificial intelligence applications. There are several reasons for this. Knowledge represented as if-then rules is easily understandable. Most people are comfortable reading rules, in contrast to knowledge represented in predicate logic. Each rule can be viewed as a standalone piece of knowledge or unit of information in a knowledge base. New knowledge can be easily added, and existing knowledge can be changed simply by creating or modifying individual rules.
There are several reasons for this:.
1- Knowledge represented as if-then rules is easily understandable.
2- Most people are comfortable reading rules, in contrast to knowledge represented in predicate logic.
3- Each rule can be viewed as a standalone piece of knowledge or unit of information in a knowledge base.
4- New knowledge can be easily added, and existing knowledge can be changed simply by creating or modifying individual rules.
5- Rules are easily manipulated by reasoning systems.
6- Forward chaining can be used to produce new facts (hence the term “production” rules).
7- backward chaining can deduce whether statements are true or not
Rule-based systems were one of the first large-scale commercial successes of artificial intelligence research. An expert system or knowledge-based system is the common term used to describe a rule-based processing system.
It consists of three major elements,
1- a knowledge base (the set of if-then rules and known facts),
2- a working memory or database of derived facts and data,
3- an inference engine,, which contains the reasoning logic used to process the rules and data.
1. Rules or Knowledge Base
– Unordered set of user-defined "if-then" rules.
– Form of rules: if P1, ..., Pm then A1, ..., An
– (Pm’s) are conditions (often facts) that determine when rule is applicable.
– (An) Actions can add or delete facts from the Working Memory.
2. Working Memory (WM)
– A set of "facts“, represented as literals, defining what are known to be true about the world
– WM initially contains case specific data (not those facts that are always true in the world)
– Inference may add/delete fact from WM
– WM will be cleared when a case is finished
3. Inference Engine
– Procedure for inferring changes (additions and deletions) to Working Memory.
– Can be both forward and backward chaining
– Usually a cycle of three phases: match, conflict resolution, and action )
A rule states a relationship between clauses (assertions or facts) and, depending on the situation, can be used to generate new information or prove the truth of an assertion.
Most rule-based systems allow rules to have names or labels such as
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
|