Basics of Power Loom Framework Java Artificial Intelligence

PowerLoom Framework:

             PowerLoom is designed to be an expressive language for knowledge representation and reasoning. As a result, PowerLoom is not a complete reasoning system but makes tradeoffs for completeness of inferences and expressivity vs. computational efficiency. It is interesting to note that Loom and PowerLoom were designed and implemented to solve real-world problems and the tradeoffs to make these problems computationally tractable have informed the design and implementation of these systems. PowerLoom does not make all possible inferences from concepts that it operates on. The PowerLoom distribution contains two very detailed examples for representing relationships between companies and for information dealing with airplanes. These examples are more detailed than the simpler example of data from news stories used in this chapter. We will look one of these examples (business rules and relations) and after working through this chapter, I encourage you to interactively experiment with the two examples that ship with PowerLoom. We will start by defining some terms used in PowerLoom: 

• concept – the Java equivalent would be an instance of a class
• relation – specifies a link between two concepts
• function – functional mapping of one concept to another
• rule – allows new concepts to be deduced without explicitly asserting them

A relation can specify the types of concepts that a relation connects. An example will make this clear and introduce the Lisp-like syntax of PowerLoom statements:

;;; Concepts:

(defconcept person)

(defconcept parent (?p person))

;;; Relation:

(defrelation parent-of ((?p1 parent) (?p2 person)))

Here I have defined two concepts: person and parent. Note that we have a hierarchy of concept types here: the parent is a more specific concept type than the person concept. All instances that are parents are also of type person. The relation parent of links a parent concept to a person concept.

We will learn more about basic PowerLoom functionality in the next two sections as we use PowerLoom in an interactive session and when we embed PowerLoom in a Java example program.