Eco Ontology Manual Draft

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1 Introduction

2 The Eco-Ontology Core

This section describes the fundamental building blocks of the eco-ontology -- called the eco-ontology core (or just "the core"). The core is represented as a single package, and all other ontologies defined within (or that extend) the eco-ontology are built from the core. The purpose of the core is to establish the set of basic semantic constructs that can be used to define more complex ecological concepts and relationships.

Things

Every concept in the eco-ontology extends the concept EcoOntThing. The name "thing" is often used informally in ontologies to denote the set of all things. Instead of "thing", we use the term object, but we retain the convention of using the term "thing" to name the most general concept. Every object in the eco-ontology is thus considered an ecological ontology "thing". Figure 1 below shows the definition of EcoOntThing. As shown, objects can be named using the hasName attribute. Object names are optional (denoted by the '0' in the cardinality restriction '0..*'), and an object may have more than one name (denoted by the '*' in the cardinality restriction '0..*').

Fig. 1: Definition of the most general eco-ontology concept.

Parts and Wholes

Objects are often described in terms of their structural relationships. One of the most basic structural relationships is the connection between parts and wholes. These part-whole relationships treat one object as the "composite", containing zero or more other objects serving as the "parts". Figure 2 shows the basic constructs used in the core for representing parts and wholes. The concepts Composite and Part are defined as sub-concepts of EcoOntThing. And composites and parts are related through the hasPart and partOf relationships, respectively.

Fig. 2: Basic part-whole concepts and relationships.

As shown, the hasPart relationship relates a composite object to zero or more parts. Similarly, the partOf relationship relates a part object to its associated composite object. A part object can participate in zero or more composite objects (that is, a part can be shared between containers).

The part-whole relationship of Figure 2 is defined to be transitive. For example, if a container c contains a part p1, and part p1 is also a container containing a part p2, then c is said to also contain p2 by virtue of transitivity. We can represent this more formally by saying that if hasPart(c, p1) and hasPart(p1, p2) is true, then hasPart(c, p2) is also true. The inverse also holds, that is, if partOf(p2, p1 and partOf(p2, c) is true, then partOf(p2, c) is also true.

Observations and Measurements

The following figure shows the basic definition of an observation, where itemMeasured is a restricted partOf relationship.