Introduction to Exsys CORVID: Expert System Development Tool

1. Introduction to Exsys CORVID Lecturer :KE TA 林泰良 Felix T. L. Lin

2. What is Exsys CORVID? • CORVID is a windows-based expert system shell. It was developed by EXSYS Inc. • You can input your knowledge and rules into the tool for developing expert systems • http://www.exsys.com/evaldl.html. Download 30-day evaluation version

3. How to start CORVID? • After installing the package, you can run CORVID program to start it • Time and size limitation • Run for 30 days and 150 logical block nodes Start it

4. CORVID Variables • They are building blocks that are used to build expert systems • Variables are used • To define logic in Logic Blocks and Command blocks • To hold data during the execution • To define the goals of how system will run

5. Variables Edit Window CORVID Variable Types • Static list – Predefined list of values • Dynamic list – List of values set at runtime • Numeric, String, Date values • Collection – Value is a group of items added by dynamically • Confidence – Value will be a confidence factor

6. Contents of the block Add IF and THEN nodes CORVID Logic Blocks • A Logic Block can be any combination of rules and decision tree • Logic Blocks are used to build the trees and individual rules that make up the logic of a system

7. Add IF nodes • For example, we have added nodes for a Static List variable “Today” • We also define a second one “Weather”

8. Add THEN nodes • In almost all cases, the THEN part of a rule will assign a value to a variable • More than one variable can be assigned values in the same group of THEN Assign value

9. CORVID Command Blocks • The Logic Blocks tell the system how to do things, but the Command Blocks tell the system what to do • Command Blocks control how a system operates • Two types of command nodes • Executable commands • Looping/branching commands

10. Executable commands • Executable commands are ones that can be directly executed • We can use Command Builder Dialog to add Executable Commands • The most commonly used commands is to derive the value for a variable or group of variables

11. Looping/branching commands • If you system requires more complex control, you can add some Looping commands such as while, for… etc.

12. Construct a Expert System • Here are two examples • An example of bulb failure expert system • An example of an advisory system for car purchasing, Page 415

13. Bulb failure expert system

14. An advisory system for car purchasing

15. An advisory system for car purchasing - Revised

16. Thank you!!