Expert System project: PC repair assistant
It is needless to say how important PCs are in our daily lives. And like every machine and device; they tend to fail from time to time. When they do, this could be a hit.
Only computer technicians have the proper knowledge and are certified to repair PCs. In this project we program that knowledge into an expert system.
Download zip fileWhat will you learn?
In this project you will learn how to program your computer to ‘know’ and master the field of computer problem diagnostics. You will learn the fundamentals of expert systems, logic programming in Prolog, knowledge base design, and inference engine implementation.
What is an Expert System?
An Expert System is a highly complex algorithm (type of AI) usually consisting of a big database and set of rules. It gathers information about a problem and provides solutions — just like a human expert would. Expert systems are used in medicine, engineering, finance, and many other domains where deep specialist knowledge can be encoded as rules.
Prolog
Short for ‘Program In Logic’, Prolog is a leading language in logic programming that was developed in 1970. It uses true/false statements derived from facts and rules, making it ideal for expert systems. Prolog is declarative — you describe what is true, and the engine figures out how to reach conclusions.
The project and its field of expertise
The expert system is designed to:
- Identify the problem
- Give guidance and explanation on how the problem was found
- Offer a solution to fix the problem
- Explain how it got to the solution and why it worked
System troubleshooting areas:
The overlay
The first requirement of an expert system is to have the ability to answer for a particular query. The system consists of four main components:
Knowledge Basis
The knowledge basis refers to the content of an expert system. It describes the components of the field of knowledge — facts and rules stored as Prolog predicates.
Conclusion Algorithm
The conclusion algorithm consists of a mechanism capable of drawing conclusions based on knowledge. It traverses the state machine to reach a diagnosis.
Explanation System
The explanation system allows an explanation to the user after the process of diagnosis and inference of the system — showing the path taken through the knowledge graph.
Overlay (Envelope)
The envelope includes the inference mechanism, the explanation mechanism and the user interface. Software installation is not required — run directly from the file.
Graphical representation of knowledge (facts)
The data structure used for this project to store all of the data is a state machine. All of the facts in this database were consulted with a real computer expert and vast research was made to make these facts accurate.
Missing
State machine diagram — Start (The pc malfunction)
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State machine diagram — PSU / I'm not sure
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State machine diagram — Display & Video
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State machine diagram — Motherboard / CPU / RAM
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State machine diagram — Hard drive
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State machine diagram — Optical drive
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State machine diagram — Sound & audio
Code structure
Edge definition
Each edge connects two states in the state machine with a value (the user's answer)._origin and _destination are the IDs of the states the arc is connecting, and _value is the transition value.
edge(_origin, _value, _destination).
Example edges:
edge(b4, no, b6). edge(b4, yes, b7). edge(b5, yes, b8). edge(b5, no, b9). edge(b7, yes, b10). edge(b7, no, b11). edge(b9, yes, b12). edge(b9, no, b13). edge(b11, no, b12).
Vertice data
Each vertex (node) in the state machine stores a name and an explanation string.
vertice_data(_vertice, _name, _explanation).
Example:
vertice_data(d12, 'Insert another power lead into the drive.', '').
Dictionary (term)
Technical terms are stored in a dictionary accessible during explanations.
term(_code, _term, _description).
Example:
term(20, 'PATA', 'Parallel ATA (PATA), originally AT Attachment (ATA), is an information cable...').
Data storage files
- data.pl — edges, vertice data, and terms
- library.pl — helper predicates and utilities
Rules
Now we get to the programming.
engine.pl methods
| Method | Description |
|---|---|
| load. | Load all files |
| start. | Start the program |
| menu. | Transfer user to main menu |
| menu(_option) | Receive user input and route |
| system_activate(_vertice, _trip) | Search method — traverses the state machine |
| system_finish_manu(_trip) | Finishes the troubleshooting process |
| explanation1(_trip) | Activates the explanation engine |
| explanation2(_trip) | Displays the trip as a flowchart |
| explanation_engine(_trip, _memory, _trip_explain) | Core explanation method |
Built-in Prolog functions used
| Function | Purpose |
|---|---|
| sort/2 | List sorting |
| member/2 | Check if value exists in list |
| atom_concat/3 | Concatenate two strings |
| findall/3 | Find all values that satisfy a condition |
| reverse/2 | Flip all values in a list |
Missing
Screenshots of the running expert system / console output
Summary
Computer hardware is an area I have delved into long enough. I decided to do the project around this topic from the beginning. Throughout the work, I had to gather a huge amount of information about all the computer parts and consult with a real expert to ensure the facts were accurate.
Preparing for the project was difficult and challenging. Eventually, I learned a great many things in the field of computer hardware and my proficiency in Prolog improved.
Thank you
We thank you for learning and hopefully completing our project. We are looking forward to hearing from you in the comment section. Questions and constructive criticism are welcome.