Year 10 · ICT · Spring 1
Effects of IT and ICT applications; databases · Lesson 3 of 5
ICT applications, part 2: expert systems and control
Theory6.3 Computer-controlled systems6.8 Expert systems6.11 Satellite systems
Year 10 · ICT · Effects of IT and ICT applications; databases · Lesson 3 of 5
You will learn to
- Name and describe the five components of an expert system.
- Explain how an expert system reaches a conclusion from the user's answers.
- Describe how robots and production lines are controlled by computer, using sensors.
- Explain how GPS works and describe one use of GIS.
Year 10 · ICT · Effects of IT and ICT applications; databases · Lesson 3 of 5
Success criteria
You have got it when you can say:
- I can name the user interface, inference engine, knowledge base, rules base and explanation system.
- I can give two uses of expert systems, such as medical diagnosis.
- I can explain how a sat nav uses satellite signals to find its position.
Year 10 · ICT · Effects of IT and ICT applications; databases · Lesson 3 of 5
Retrieval starter
Questions from before. Write your answers, then show them.
- Last lesson
A foreign key…
A Links a record to a record in another tableB Is a passwordC Is always unique
A. Links a record to a record in another table
- Last unit
Exporting means…
A PrintingB DeletingC Saving in a format another program can open
C. Saving in a format another program can open
- Earlier this year
In automatic stock control, the stock level drops when…
A The manager countsB The shop closesC The barcode is scanned at the till
C. The barcode is scanned at the till
Year 10 · ICT · Effects of IT and ICT applications; databases · Lesson 3 of 5
Key words (1 of 3)
- Computer model
- A program that uses rules and formulas to act like a real system.
- What if
- Changing a model's inputs to see what would happen.
- Production line control
- Using sensors, computers and robots to run a factory line automatically.
- Expert system
- Software that copies the knowledge and decisions of a human expert.
Year 10 · ICT · Effects of IT and ICT applications; databases · Lesson 3 of 5
Key words (2 of 3)
- Inference engine
- The part of an expert system that applies rules to facts to reach conclusions.
- Knowledge base
- The store of facts in an expert system.
- Rules base
- The IF … THEN rules in an expert system.
- GPS
- Global positioning system: satellites that let a receiver work out its position.
Year 10 · ICT · Effects of IT and ICT applications; databases · Lesson 3 of 5
Key words (3 of 3)
- GIS
- Geographic information system: location data shown as layers on a map.
6.3 Computer-controlled systems · The explanation · step 1 of 7 · part 1 of 3
Robots, production lines and autonomous vehicles
Factory robots weld car bodies, spray paint, assemble parts, and pack and lift heavy items.
Robots are programmed by writing instructions, or by a person guiding the arm through the task once while the robot records the movements.
In production line control, sensors detect each item on a conveyor belt. Cameras check quality, faulty items are pushed off, and good items are counted and packed automatically.
6.3 Computer-controlled systems · The explanation · step 1 of 7 · part 2 of 3
Robots, production lines and autonomous vehicles (continued)
Autonomous cars, buses, trains and aircraft are computer-controlled systems too. They follow a loop: sensors collect data, the microprocessor compares it with stored data and rules, then actuators steer, brake or accelerate. Their effects are covered in topic 5.
| Advantages | Disadvantages |
|---|---|
| Work 24 hours a day without breaks, so higher output | Very expensive to buy, install and maintain |
| Every item made to the same standard, so consistent quality | Workers lose jobs or need retraining |
| Can work in dangerous places (fumes, heat, heavy loads), so safer for people | Cannot easily deal with unexpected situations |
| Lower running costs than paying many workers over time | A fault can stop the whole production line |
6.3 Computer-controlled systems · The explanation · step 1 of 7 · part 3 of 3
Robots, production lines and autonomous vehicles (continued)
6.8 Expert systems · The explanation · step 2 of 7
What an expert system is and where it is used
An expert system is software that copies the knowledge and decisions of a human expert in one area.
Uses: medical diagnosis, mineral prospecting (where to dig for oil or metals), car engine fault diagnosis, playing chess, tax advice, and strategy games.
It asks the user questions, applies rules to the answers, and gives a conclusion with a probability, plus an explanation.
6.8 Expert systems · The explanation · step 3 of 7 · part 1 of 4
The five components
Try the expert system below. It finds out why a laptop will not start. Answer its questions and watch the inference engine apply rules from the rules base (the toy calls it the rule base) to the knowledge base. Then read How I decided: that is the explanation.
6.8 Expert systems · The explanation · step 3 of 7 · part 2 of 4
The five components (continued)
| Component | What it does |
|---|---|
| User interface | Asks the user questions on screen, usually yes/no or multiple choice, and shows the results. |
| Explanation system | Explains how the system reached its conclusion, and its probability or confidence. |
| Inference engine | The "thinking" part. Applies the rules to the facts and the user's answers to reach conclusions. Decides which question to ask next. |
| Knowledge base | Stores the facts about the subject, collected from human experts. |
| Rules base | Stores the IF … THEN rules that link facts to conclusions. |
6.8 Expert systems · The explanation · step 3 of 7 · part 3 of 4
The five components (continued)
6.8 Expert systems · The explanation · step 3 of 7 · part 4 of 4
The five components (continued)
Learn the five names exactly. "Database" is not the same as "knowledge base", and "processor" is not "inference engine".
There is something to try for this step in the IGCSE library.
6.8 Expert systems · The explanation · step 4 of 7
Setting up an expert system, and its pros and cons
To build one: interview experts to collect knowledge; build the knowledge base and rules base; build the inference engine; design the user interface and explanation system; test it against known cases.
| Advantages | Disadvantages |
|---|---|
| Gives consistent answers; does not get tired or emotional | Only as good as the rules entered; errors give wrong advice |
| Knowledge of many experts in one system | Has no common sense; cannot handle situations outside its rules |
| Available 24/7 and in many places at once, even where there is no expert | Expensive to set up and keep up to date |
| Fast; gives probabilities and explains its reasoning | Users may trust it too much; lacks a human expert's empathy |
6.11 Satellite systems · The explanation · step 5 of 7 · part 1 of 2
GPS and satellite navigation
The global positioning system (GPS) uses at least 24 satellites orbiting the Earth. Each sends signals with its exact position and the exact time, from an atomic clock.
A receiver measures how long each signal took to arrive. That gives its distance from each satellite. Using at least three satellites (usually four for accuracy), it calculates its position, often to within a few metres.
Satellite navigation (sat nav) combines this position with stored maps, so it can show where you are and plan a route.
6.11 Satellite systems · The explanation · step 5 of 7 · part 2 of 2
GPS and satellite navigation (continued)
| Advantages of sat nav | Disadvantages of sat nav |
|---|---|
| Driver does not need to read a map, so safer and less stressful | Maps may be out of date: new roads or closures missing |
| Finds the fastest route and reroutes around traffic jams | Can send drivers down unsuitable roads, e.g. lorries on narrow lanes |
| Finds nearby fuel stations, hotels and car parks | Signal can be lost in tunnels, between tall buildings or in dense forest |
| Spoken directions let the driver watch the road | Drivers lose map-reading skills and rely on it too much |
The explanation · 2 more steps
More on the lesson page
The lesson page has the rest of the explanation, step by step:
- Geographic information systems (GIS)
- Media communication: satellite TV and phones
Year 10 · ICT · Effects of IT and ICT applications; databases · Lesson 3 of 5
Quick quiz · 1 of 3
A report grouped by Form means…
- A Only one record shows
- B Each form's records appear together, with a count or total per group
- C The records are in random order
B. Each form's records appear together, with a count or total per group
Grouping with run-time calculations is a practical-paper favourite.
Year 10 · ICT · Effects of IT and ICT applications; databases · Lesson 3 of 5
Quick quiz · 2 of 3
A calculated field…
- A Is a primary key
- B Must be typed by hand
- C Works out a value from other fields when the query runs
C. Works out a value from other fields when the query runs
Percentage: [Score] / 80 * 100.
Year 10 · ICT · Effects of IT and ICT applications; databases · Lesson 3 of 5
Quick quiz · 3 of 3
A pie chart is for…
- A Change over time
- B Comparing 30 categories
- C Parts of a whole
C. Parts of a whole
Few slices, adding up to the total.
Year 10 · ICT · Effects of IT and ICT applications; databases · Lesson 3 of 5
Exit ticket
Answer on paper before you go. Then check.
A line chart is for…
A Unrelated categoriesB Change over timeC Parts of a whole
B. Change over time Temperature by month, sales by year.
A legend shows…
A Which colour is which data seriesB The axis scaleC The chart title
A. Which colour is which data series Needed when there is more than one series.