1. DOMAIN ONTOLOGY DESIGN
Boriana Deliiska
University of Forestry, Sofia, Bulgaria

2. Definitions of ontology
formal, explicit specification of a shared conceptualization, used to help programs and humans share knowledge (Gruber,1993)
O = <X,R,F>, where X — end set of entities about a domain, R — end set of relations between entities, and F — end set of interpretation functions.

3. Ontology classification
task ontologies
application ontologies
domain ontologies
knowledge representation ontologies (or representation ontologies)
top-level ontologies (upper-level ontologies or foundation ontologies)
core ontologies (generic ontologies or meta-ontologies)
general (common) ontologies

4. Ontology structure Basic elements:
classes (or nouns). A class can have subclasses;
properties of each class (so called roles or slots) which describe classes and instances;
restrictions on slots (called role restrictions or facets);
instances of classes.

5. Ontology structure Advanced elements:
relations (or verbs) which represent a type of interaction between concepts of the domain (for example is-a, subclass-of and connected-to, has-part, etc). There are some special case of relations named functions;
axioms – the definitions of concepts and constraints on their interpretation;
rules – behaviour prescriptions of events.

6. Main activities in ontology building
Determine the domain and scope of the ontology
Consider reusing existing ontologies
Enumerate important terms in the ontology
Define the classes and arranging the classes in a taxonomic (subclass–superclass) hierarchy
Define the properties (slots) of classes
Define the facets of the slots. In this step slot cardinality, slot-value type and domain and range of a slot are defined.
Create instances
Create a knowledge base

7. Languages for ontology modeling
Prolog,
XML,
OKBC (Open Knowledge Base Connectivity),
OWL (Web Ontology Language),
DAML+OIL (Ontology Inference Layer+Darpa Agent Markup Language),
KIF (Knowledge Interchange format),
LOOM,
XOL (XML-based Ontology exchange Language),
RDF, etc.

8. Platforms for ontology management
More than 50 software tools. The most popular are:
Protégé 2000;
OWL Ontology Validator;
IBM Ontology Management;
RACER System;
OilEd;
Chimaera Ontology Environment;
Ontolingua;
Pellet OWL Reasoner;
WordMap Taxonomy Management etc.

9. Domain ontology of forestry
The most extensive ontology of forestry is:
NEFIS project [10] which continues the activities of EFIS (European Forest Information System);
Global Forest Information System (GFIS) coordinated by IUFRO.

10. Preconditions
Current ontology of forestry is on the base of multilingual dictionary and the respective database in this area.
The dictionary database contains about entries.
The leading language is English and each entry has its German, French and Russian equivalents. The Latin name of forest species is included also.

11. Main activities in forestry ontology design
design of taxonomy of forestry, identifying classes, subclasses and superclasses;
addition of missing entry definitions;
defining of relation set;
development of extended structure of the dictionary database.

12. Classes of forestry taxonomy
forest management (forestry) → economy
forest policy → policy
forest science → biology → science
forest → nature

13. Relations is-a, is-part-of, is-kind-of, is-subclass-of, is-located-in,
is-instance-of,
is-member-of,
join-with,
is-synonym-of etc.

14. Example of XML description
<domain><entry name>forestry</entry name>
<class><entry name>forest science</entry name>
<subclass><language>English
<entry name>dendrology</entry name>
<definition> A branch of forestry which...</definition></language>
<language>French<entry name>
dendrologie</entry name></language>
...
</subclass>
</class> ...
</domain>

16. Forestry ontology database structure

17. Thank you!