ICT in Healthcare

Expert Systems

Expert Systems

• An ICT system that uses artificial intelligence (AI) to make decisions based on data supplied in the form of answers to questions

AI

• An AI is a reasoning process performed by computers to:– Draw deductions– Produce new information– Modify rules or write new rules

Neural Network• A NN is a biological system that is used by the

brain for learning new things• It allows ICT systems to learn by example like

humansAdvantages Disadvantages

Are good where algorithms cannot be developed

Only suited to different tasks

Can identify structures in data Time can be wasted and the system can be unpredictable if not chosen carefully

An Expert System• A huge organised set of knowledge about a

particular subject. It contains facts and judgemental knowledge which gives it the ability to guess like a human

• A set of rules on which to make decisions (using the if-then structure). The Inference engine does reasoning by manipulating the knowledge base

• The user interface presents questions and information to the operator and also receives answers from the operator

Knowledge Base

Inference Engine

User Interface

How to expert systems work• An operator interacts with the UI and answers

a series of questions.• Each question gets passed to the inference

engine which makes a decision depending on the reply.

• The inference engine looks in the knowledge base in order to find the most relevant question/answer

• It is then presented to the UI.

How to make an Expert System

1. Build the system from scratch using a software language suited to your task

– Program using PROLOG or ASPRIN

2. Use a piece of development software called an expert system shell

– The shell contains a inference engine and user interface, but requires an expert to create a knowledge base

– This can be done with little programming skill, but knowledge of an expert system is needed

MYCIN – Medicine expert system

• Questions the user on symptoms (from a Knowledge base of 500 rules)

• Will ask for certain tests if needed• After the symptoms it will advise on the best

medication• Can also provide alternative medication with

expected success rate

Advantages/disadvantages of an Expert System

Advantages Disadvantages

Consistency – they provide consistent answers for repetitive decisions

No common sense – i.e. If someone had been shot and was bleeding, the system would still look for a cause

Cheaper – they are cheaper than using a human expert such as a GP

Can make absurd errors if data is entered incorrectly, i.e. Weight and height entered the wrong way around

The expert system can consult a much larger pool of knowledge compared to a human

Not able to provide a creative response in certain situations

Available 24/7 Not being able to realised when no answer is available to the problem

The Computer uses all the information it has, unlike a human who can forget

Relies on rules and knowledge being correct. Any mistakes may cause an incorrect diagnosis