Chapter 7: Expert Systems

Question 1

what is an expert system

how does it gather data

Answer 1

• uses a set of rules/ knowledge to provide a diagnosis
• used to solve complex problems
• by asking the user questions about their problems

Question 2

3 main components of an expert system

Answer 2

1- the knowledge base
2- the inference engine
3- the user interface

Question 3

knowledge base

Answer 3

1) factual
2) heuristic (acquired through a range of experiences and reasoning. )

knowledge base editor

Question 4

inference engine

what is forward chaining

Answer 4

• ask user Q, use a line of logic to find the A
• chains together IF(condition)-THEN(action) rules to form a line of logic
• when the process starts with a set of conditions and chaining moves towards a final conclusion
• data drivem

Question 5

ADV of expert systems

Answer 5

• outside a user’s knowledge and experience.
• accessed on a 24/7 basis.
• no errors, no forget to ask Q or a knowledge
• reduce the time taken

Question 6

disadvantage of expert systems

Answer 6

• no common sense/ creativity to their solution
• only as good as the data and rules they are given.
• not able to automatically adapt to changing environments
• expensive to produce

Question 7

data processing system: batch
what is

adv

disadvantage

stock control

payroll

online booking system

Answer 7

storing data in batches
processing when system low demand

less disruption when there is high dd
auto

delay

• info about each item sold can be batched together and processed at the end of the day to be sent as a report to the warehouse.
• The warehouse will then know what stock to send the next day.
• system is freed up to deal with all of the sales made in the store during the day.
• Data about each employee’s working hours can be stored in batches until the employees need to receive their pay.
• processed to calculate the pay pay-slip can be output to show this.
• It is not necessary to have an employee’s pay calculated until they are due to be paid, so the processing to do this can be run when the factory isn’t in operation, e.g. late at night. This will free up the processing power of the system to perform other tasks during the day.
• All the data about the customer, flight and seat number will be collected in the transaction.
• processed and a ticket can be provided as an output. - - - As each transaction is processed in turn, this avoids a seat on the airplane being double-booked.
• Once a seat has been allocated to a transaction, until that transaction is completed that seat cannot be booked by anyone else.
• This is because their transaction will not be processed until the previous one is completed.

Question 8

data processing systems : real time

air traffic

comp game

Answer 8

• process data as soon as it has been input
• when the immediacy of the result is vital

For data to be processed it is often stored first. This can be for long periods of time or momentarily. There are two main file type

location of all the planes currently in the air, is processed immediately so that their location can be known by everybody using the system. This is imperative as this data will need to be given back to each plane that is currently in flight to make sure no collisions occur. There cannot be any delay in the processing of this data as the result could be catastrophic.

When playing computer games the input from the user needs to be processed immediately, so that it can take effect and the game can be controlled. Each time a user asks a game character to move forward by pressing a key or button, it needs to do this immediately. In order to do this, it needs to have a real-time processing system to process the data.

Question 9

master file

Answer 9

collection of fields about a main element of a data system,

permanent data

key field will be used to match transaction files to the correct master file.

Question 10

transaction file

real time

batch

Answer 10

• used to update the master file.
• more temporary
• key field will be used to match transaction files to the correct master file.
• company to see what updates have been made to the master file at various times.
• transaction file is compared to the master file, by finding the matching key field, as the data is processed by the system
• ransaction files are stored until a suitable time is available to update the master files.