What is Protégé-2000?
Protégé-2000 is an integrated software tool used by system developers and domain experts to develop knowledge-based systems. Applications developed with Protégé-2000 are used in problem-solving and decision-making in a particular domain.
While our earlier Protégé/Win, like a classical database system, separately defined classes of information (schema) and stored instances of these classes, Protégé-2000 makes it easier to work simultaneously with both classes and instances. Thus, a singular instance can be used on the level of a class definition, and a class can be stored as an instance. Similarly, slots, which earlier were employed only within classes, are now elevated to the same level as classes. With this new knowledge model we also facilitate conformance to the Open Knowledge Base Connectivity (OKBC) protocol for accessing knowledge bases stored in knowledge representation systems. Finally, applications on top of these components are also executed within the integrated Protégé-2000 environment.
The Protégé-2000 tool accesses all of these parts through a uniform GUI (graphical user interface) whose top-level consists of overlapping tabs for compact presentation of the parts and for convenient co-editing between them. This "tabbed" top-level design permits an integration of (1) the modeling of an ontology of classes describing a particular subject, (2) the creation of a knowledge-acquisition tool for collecting knowledge, (3) the entering of specific instances of data and creation of a knowledge base, and (4) the execution of applications. The ontology defines the set of concepts and their relationships. The knowledge-acquisition tool is designed to be domain-specific, allowing domain experts to easily and naturally enter their knowledge of the area. The resulting knowledge base can then be used with a problem-solving method to answer questions and solve problems regarding the domain. Finally, an application is the end product created when the knowledge base is used in solving an end-user problem employing appropriate problem-solving, expert-system, or decision-support methods.
The main assumption of Protégé-2000 is that knowledge-based systems are usually very expensive to build and maintain. For example, the expectation is that knowledge-based system development is a team effort, including both developers and domain experts who may have less familiarity with computer software. Protégé-2000 is designed to guide developers and domain experts through the process of system development. Protégé-2000 is designed to allow developers to reuse domain ontologies and problem-solving methods, thereby shortening the time needed for development and program maintenance. Several applications can use the same domain ontology to solve different problems, and the same problem-solving method can be used with different ontologies. For more information about building knowledge-based systems and the Protégé-2000 approach, see Planning a Protégé-2000 Project.
Protégé-2000 is currently being used in clinical medicine and the biomedical sciences, although it can be used in any field where the concepts can be modeled as a class hierarchy. Throughout this online guide, you will see examples of a newspaper domain used to illustrate points of explanation; for more information about this running example, see an overview of the Newspaper Example.