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by Johnson Hou


Type Tab Widget
Author(s) Johnson Hou
Last Update July 7, 2005
License Mozilla Public License
Homepage EZPal website
For Application

Facilitate acquisition of Protege Axiom Language (PAL) based constraints without having to understand the language itself.


Versions & Compatibility

This section lists available versions of EZPal.

No version information available.

If you click on the button below to add a new version of EZPal, you will be asked to define a page title for the new version. Please adhere to the naming convention of EZPal X.X.X when you define the new page!


No version information available.

Detailed Description

EZPal is a tab widget plug-in for Protege that was designed to facilitate acquisition of Protege Axiom Language (PAL) based constraints without having to understand the language itself. Using a library of templates based on reusable patterns of previously encoded axioms, the interface allows users to compose constraints using a "fill-in-the-blanks" approach that parallels the object-attribute-value representation metaphor of Protege.

Organizational Overview

The tab makes use of a Protege ontology to store three major categories of information EZPal presents in the interface:

  • Pattern: A pattern is defined as a logical sentence derived from a group of axioms that are structurally identical except for specific references. Individual patterns are not stored explicitly in the library but further generalized into templates. The form at the bottom right corner which allows value inputs for axiom-instantiation is a particular pattern representation of a template.
  • Template: each template describes a set of frequently used axiom design patterns based on their semantic and structural similarities, or possibly one pattern only if it is unique. It stores the relevant 'variation' information to allow retrieval of a specific pattern to allow value entries for axiom generations.
  • Property: A property is an abstract description for the common features of a group of templates. Properties are not mutually exclusive: each template may satisfy more than one property.

Currently, the library has 20 templates and 4 properties.


EZPal is bundled with the "full" installation of Protege.

The source code for EZPal is available in the Protege Subversion repository.

System requirements: Must have the PAL Constraints Tab enabled and include the "template" project (comes with the default installation) before enabling EZPal.


EZPal documentation is hosted on the main Protege website:

View documentation

View reference paper

Level of Support

This plug-in is no longer under active development.

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