 You will be able to: › Explain what is meant by an expert system and describe its components and applications.

 Society is becoming more complex.

 More and more information is becoming available.

 Systems need to be designed to deal with information so that it can be found more easily by humans.

 Alternative name is knowledge-based system.

 Consider: › The problem of diagnosing a patient’s illness.

› Doctors can break down the symptoms and use their knowledge and possibly tests on the patient to try and figure out what the probably illness is.

› Sometimes it takes a team of doctors to work out what the problem is.

 Now consider: › A computer that has all the information stored about every illness known to man.

› It stores information such as symptoms and treatments.

› As a patient describes their symptoms the doctor can input these into the system and the computer displays all the illnesses that match up with the symptoms.

› Using the new facts the doctor can eliminate tests that do not need to be carried out and it lowers the risk of mis diagnosing patients.

 Expert systems usually contain the knowledge of a large number of specialists.

 They can search through information very quickly  much faster than a human.

 Less likely to forget details about rare diseases, unlike a human.

 Could be used by people to decide if they need to go to the doctors or not.

› A bit like the family doctor books!

 Can sometimes be expensive to be set up.

 They still rely on accurate information being put into the system. One mistake could be costly!

 Useless if asked questions outside their knowledge bank.

 Can people really trust a machine??

 Will compose of a natural language interface.

 The ultimate aim is to be able to hold a conversation with a computer.

 The Turning Test › Alan Turning developed a simple test to see if a computer possessed intelligence.

› People had to work out if they were talking to another person or a computer.

› Most people realised that it was a computer.

 Symptoms tend to exist for many types of illnesses.

 It is unlikely that the expert system will find one illness that meets all the criteria.

 Multiple responses may be given for a headache, high temperature and cough for example: › Common Cold = 61.78% chance › › Influenza = 38.21% chance Bubonic plague = 0.01% chance

 There are four parts to an expert system: › The knowledge base › › The rule base The inference engine › The user interface

The knowledge base The rule base The inference engine The user interface user

 This sections holds the facts.

 It will hold information related to the topic that the expert system is intended for.

 This section holds rules that need to be applied to the knowledge base.

 For example: › › › IF a toe nail is swollen AND the nail is black OR there is puss THEN it could be an in-growing toenail.

 This is the brains of the system.

 It is where all the clever bits happen.

 It separates the user interface from the clever bit of the system.

 It allows different user interfaces to be created to suit different needs…the knowledge base remains the same…its only the interface that changes.

 The user will need an interface through which they can interact with the system.

 The interface may display closed questions which will result in different responses being displayed.

 One day open ended questions might be accepted.

 For each type you will need to be able to describe an example.

› › › Diagnostic systems Advice-giving systems Decision making systems

 Asks a question to narrow down the number of results from the knowledge bank.

› Classic example is the medical system we have already covered.

 Consider the following diagram and note how the knowledge bank gets smaller.

Question 1 Question 2 Knowledge bank Yes No Yes No Yes No Question 3 Yes No Yes No Yes No Yes No

 A stock monitoring system is a good example of this.

 It monitors the level of stock and then when levels drop too low it will advise that stock may need to be reordered.

 This would then be done manually if they want to continue stocking that particular product.

 A more advanced system compared to advice-giving systems.

 Taking the stock example again: › Stock can be reordered automatically when conditions meet specified requirements such as:   Stock level falls below a set level Time of year and market trends   Number of sales in recent days, weeks, months etc Etc…

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Define a ‘knowledge-based system’ Describe the parts that make up a knowledge-based system, using examples where you can.

What are the characteristics of an expert system?

State three types of knowledge-based system and give examples of each.

What is the essential difference between an advice giving system and a decision-making system?

Describe the pros and cons of introducing a medical expert system into a third world country in place of a doctor.