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Knowledge Base Systems
Topics Covered
� What is an expert?
� What are expert sysems in the context of A.I?
� Charactertistics of Expert Systems
� Componets of Expert Sustems
� Expert Systems Apllication Domains including:
� Medcine
� Engineering
� Science
� Business
� LAW
� Rule base Expert System
� What is meant by Fact in Expert System
� What are rules
� Examples of how Facts and Rules are defned and stored
Introduction
� It’s more than 60years ago when Alan Turing, the great British mathematician designed a test to judge whether machines can outwit human beings.
� The test which is used by many experts in the field of A.I today, was designed to investigate whether people can detect if they are talking to a machine or human.
� The machine is declared a winner, if it manages to convince more than 30% of human judges into believing that it is not a machine but a human.
� Currently, it’s not possible to conclusively say that machines have developed the ability to think. But since Alan Turing’s experiment, the development of smart machines capable of outperforming humans in certain domains have been growing.
Introduction Con’t
� This follow up post on the subject of Artificial Intelligence will focus on discussing Expert systems and the role of traditional experts in their design and development.
� We shall explore in particular four main themes:
� What do we mean by Expert?
� How do experts work?
� Expert Systems Apllication Domains, and
� Features of rule based Expert (KB) Systems
What do we mean by Expert?
What do we mean by Expert?
� The term expert is over used nowadays to the extend that it’s at risk of
losing its true meaning and a lot more.
� During the June Brexit referendum campaign for example, Michael Gove,
the then secretary of state for justice declared “people in this country have
had enough of experts,” this piece is not about whether experts should be
trusted or not. But to introduce the basic concept of rule based expert
systems and their use cases
� For a start, experts are people with deep knowledge of specialist fields
and skills gained through many years of practise and learning
� Put another way, an expert is a person or an artificial agent with special
knowledge and skills gained after many hours of training and practice.
Taking it further
� The online business dictionary definition of an expert is perhaps the most comprehensive. It define expert as:
� A professional who has acquired knowledge and skills through study and practice over many years, in a particular field or subject, to the extent that his or her opinion may be helpful in fact finding, problem solving, or understanding of a situation.
� Experts are not only highly trained individuals, they reflect on their practice, continue to study and keep their knowledge up-to-date
Experts are Knowledge Workers
Knowledge Workers
� People who use their knowledge to create, use and share information, are known as knowledge workers. To name but a few:
� Lawyers, including barristers and solicitors who use their knowledge of law to advice and defend their clients
� Doctors use their knowledge of how the body works, diagnostics techniques and understanding of medicine to cure patients
� Information systems experts use their knowledge of information technology (Hardware and software) to design new systems that improve business process and make life better for end users
Knowledge Workers
� Expert Equation= Lots of facts + use of deductive logic + good understanding of how to solve complex problems
Question?
Is it possible to fully automate
human expertise?
More specifically, can the skills and
knowledge of a human expert be
captured and encoded?
What then is an Expert System?
Expert Systems
� Again this has many different meaning, but to keep it simple, an expert system is an artificial intelligence (AI) application that emulate human traits and perform complex tasks as a human expert would.
� Expert Systems are Knowledge Base Information Systems designed in most cases to offer support to human users in a particular field-medicine, law, insurance, etc
� That means knowledge in an expert system is domain specific and consist of facts and rules about the domain
� Like a human expert, experts systems are used in knowledge discovery, solving complex problems, and aiding humans in understanding complex situation.
Input from human Experts are crucial
Input from human experts are crucial
� The success of an expert system project depends on the quality of facts (data) and rules obtained from a human expert or users.
� We shall consider this in more details when discussing knowledge representation repository design in a future post
Characteristics of Expert Knowledge
Characteristics of an Expert Knowledge
� Expert systems are different from traditional information systems.
� They do more than just capture, process and store information. Experts Systems are capable of building on human knowledge, experience and discover new things on their own
� They are therefore expected to be amongst other things, highly reliable, flexible, efficient and provide a clear explanation of decision, (Giarratano and Riley, 2007)
Characteristics of Expert Knowledge
� An effective expert system is:
� Capable of responding at a level of competency equal to or better than a human expert
� Able to perform in a reasonable time, comparable to or better than human
� Able to explain the steps of its reasoning to the end user
� Built with facilities to enable users add, change, and replace dated knowledge
Components of Expert System
Components of Expert System
� Expert systems are made up of four major components:
� Knowledge base
� Inference Engine
� Interactive user interface, and
� An actives working memory
Components of Expert System
Working memory
fact base
Knowledge
base
Inference /Interface
Engine
Subject Experts Knowledge Engineer ES Developer
End user
With computer &
interface
Receives
expert advice
Ask question
or query
How the various components work together
23
How they work
� Expert systems solves problems or provide answers to users questions by:
� Comparing rules and facts stored in knowledge base and facts in memory respectively to produce result
� The main component that does the comparing or reasoning is called the inference engine.
� Any new fact obtained from users are added to the database and used to train the system for better performance
Expert System Application
Areas of use
� Knowledge base systems are used in many fields, including:
� Medical diagnostics
� Engineering equipment repair
� Financial decision, e.g. investment analysis
� Estate and insurance planning
� Transport, vehicle driver routing and navigation
� Manufacturing production control and
� Education and training
Real world examples
Application of expert systems to business problems
� Applications of expert systems technology to a wide variety of specific knowledge fields and problems
� See this list by World Technology Evaluation Center (WTEC), Division of Loyola University Maryland:
http://www.wtec.org/loyola/kb/c1_s2.htm
Expert systems Application
Artificial Neural Network
Automatic Self
service
The development of expert systems is a team effort
How are they developed?
The Development Team
� Team members involve in a typical expert system development project:
� Domain subject experts
� Knowledge engineer or Analyst
� System Engineer or developer
� Expert System user
Why Expert Systems
Are Expert Systems better than human experts?
Are Expert Systems better?
� The debate about performance gap between human experts versus intelligence machines is on going
� The limit of human capacity to make decision and solve problem pose great challenges to the wellbeing and prosperity of society.
� Expert System can be programmed to run on their own logic and intelligence.
� More often than not humans act out of emotion, insecurity, irrational thoughts, and personal beliefs that confuses how the world work with how they think the world ought to work.
But does that makes them better than human experts?
I am not sure, what do you think?
What are Rules and Facts in Expert Systems
What are Rules and Facts in Expert Systems
� The most important component of an expert system is perhaps the knowledge base
� Knowledge base comprises of:
� Domain specific data or fact, often expressed as a condition
� Rules for reasoning and for accomplishing task in the specific domain (condition & outcome)
� Both are structured so that they can aid reasoning
What is factual statement
Change the Facts not the Rules, says the great sage
What are facts and How do we know?
� A fact is something that has really occurred or is actually the case and known to be true.
� A statement is factual if it can be validated and verified
� The usual test for a statement of fact is whether it can be demonstrated to correspond to experience.
Examples of random factual statements
�Most mammals are hairy
� Humans are mammals
� All mammals are worm blooded
� January is the first month of the year
� the size of middle class in Africa is growing
� Sleep is necessary
� Humans need food to stay alive
Examples of random factual statements
� Students who hand in their work late score less mark
� Immigration visa is issued to applicants who score more than 60 points
� Over draft fees are charged to customers who exceed an agreed limit
� The pass mark for BCS Exam is 40%
� BCS exams this year is in March
How can you be sure of your facts?
How would you check a statement for its
accuracy and validity?
Expert Systems Rules
What do we mean by Rules in an Expert System?
Rules
� In problem solving or artificial intelligence, rules are forms of knowledge expression.
� A way to express understanding of what the facts are and how they apply in practice
� Rules provide some description of how to solve a problem or perform a task
� Rules are the popular paradigm for representing knowledge.
The Building Block of rules
� Rules are made of two main parts, namely an “IF….” part and “THEN….” Part. Condition of an event, real world object on one hand and possible outcome on the other
� A rule based expert system is one whose knowledge base contains the domain knowledge encoded in the form of rules.
Rules for various fields of knowledge
� Can you work out the Rules for the use cases below:
� Making a scientific discovery
� Data mining and knowledge discovery
� Health promotion campaign
� Solving a complex mathematical problem
� Teaching someone how to learn effectively
� Deducing intelligent behaviour
� Building a new computer software
� Solving a complex crime, like inspector Colombo would
Rules outline how work is done or how to solve a problem
Thinking in Rules
Thinking in Rules
� Rules base thinking can be applied to:
� Situations and expected actions
� Premises and conclusions, and
� Antecedents and consequences
Situations and Expected Actions
� Situation refers to a condition or an event
� Action by definition is what should be done if the condition is satisfied
� A simple illustrated example: � IF traffic light shows red Then stop, do not cross the road.
� IF total point scored < 60 THEN Reject visa Application
� IF customer account is >=10% over drawn THEN charge Overdraft fee
Premise and Possible Conclusions
� Premise is defined as a statement or an idea on which a reason is based
� The statement may be true or false
� Conclusion, could referred to as end result or a final point
Premise and Possible Conclusions
� Example
� IF student continue to absent themselves from class THEN it means they have other interfering activity
� If the account holder has low credit score THEN they are high risk, their loan application should be rejected
� If the sky is cloudy THEN it is likely to rain
� If a product is scarce THEN sellers will charge more for it
Antecedent and Consequences
� The term Antecedent refers to a thing or event that exist or occur before another. Put simply, it’s simply, ancestors to a person, an object, event or process
� Remember, generalisation and specialisation
� Consequences may be defined as: The outcome of a course of action. E.g. the outcome of an event
Antecedent and Consequences
� Example:
� IF x is a dog then x is an animal.
� IF student attendance <=70% THEN they would not pass their exam
� IF x is a girl THEN x is a Female
� IF x head injury is severe THEN x should be rushed to emergency hospital
� IF y is fitted with complicated systems THEN it will cost more to repair it
Thanks for your attention
Keep in touch and let me know what you think
To find out more:
Peter Jackson, Introduction to Expert Systems, Addison-Wesley (3rd Ed), 1998, ISBN 0201876868978-0201876864
Alison Cawsey, The Essence of Artificial Intelligence, ISBN-13: 978-0135717790 ISBN-10: 0135717795
Pedro Domingos, (2015) The Master Algorithm: How the Quest for the Ultimate Learning Machine Will Remake Our World
To find out more:
http://www.bcs.org/upload/pdf/pgdkbssyll.pdf
http://www.businessdictionary.com/definition/expert.html#ixzz3RJxhhhlK
http://users.cs.cf.ac.uk/Dave.Marshall/AI1/mycin.html
http://www.codeproject.com/Articles/179375/Man-Marriage-and-Machine-
Adventures-in-Artificia
MYCIN Artificial intelligence program
https://www.britannica.com/technology/MYCIN
https://www.deepdyve.com/browse/journalslp/expert-
systems?gclid=CJ2LrojGjNACFUoW0wodwXIFhQ
