Expert Systems

What is an Expert System?

An expert system is computer software that attempts to act like a human expert on a particular subject area.

Expert systems are often used to advise non-experts in situations where a human expert in unavailable (for example it may be too expensive to employ a human expert, or it might be a difficult to reach location).

How Do Expert Systems Work?

An expert system is made up of three parts:
A user interface - This is the system that allows a non-expert user to query (question) the expert system, and to receive advice. T|bn\Uerface is designed to be a simple to use as possible.
A knowledge base - This is a collection of facts and rules. The knowledge base is created from information provided by human experts
An inference engine - This acts rather like a search engine, examining the knowledge base for information that matches the user's query.

Process Flow Diagram

A Process Flow Diagram - PFD - (or System Flow Diagram - SFD) shows the relationships between the major components in the system. PFD also tabulate process design values for the components in different operating modes, typical minimum, normal and maximum. A PFD does not show minor components, piping systems, piping ratings and designations.

A PFD should include:

Process Piping
Major equipment symbols, names and identification numbers
Control, valves and valves that affect operation of the system
Interconnection with other systems
Major bypass and recirculation lines
System ratings and operational values as minimum, normal and maximum flow, temperature and pressure
Composition of fluids

This figure depict a small and simplified PFD: