icas-ontology

This is the unified ICAS ontology designed to describe the abstraction of information-security related information as used by performers on the DARPA ICAS project.

Distribution

Distribution Statement “A” (Approved for Public Release, Distribution Unlimited)

License

Copyright (c) 2014-2016 Invincea Labs, LLC.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

A Brief Explanation of OWL and RDF

The unified ICAS ontology is a collection of OWL2 ontologies under the http://www.invincea.com/ontologies/icas/1.0/ namespace. Each ontology covers a specific conceptual area; for instance all information related to users and user accounts is captured in the User ontology.

OWL2 is an ontology description language built on top of the Resource Description Framework (RDF). RDF describes a way of storing data that is different from the traditional table-based conception. RDF data consists of triples, and only triples; each triple, called a statement consists of a subject, predicate, and an object.

The subject represents a resource of some kind, the predicate a relation, and the object can either be a literal value or another resource.

OWL2 and the RDF Schema (RDFS) define a set of resources and properties that can be used to develop ontologies for RDF datasets.

Examples

This section contains some annotated excerpts from the ontologies as examples of how to read RDF and OWL. These examples are encoded in the Terse RDF Triple Langauge (Turtle), just like the ICAS ontology. This is intended only as an overview and omits many details

Turtle Primer

Recall that RDF consists only of statements, each of which is composed of a subject, a predicate, and an object. In the Turtle encoding, there is a shorthand creating multiple statements that uses the ; to indicate continuation with the same subject. The following example shows how to interpret this syntax.

<subject> <predicate> <object> ;
            <predicate> <object> .

<subject-2> <predicate-2> <object-2> .

UserAccount Class

This example depicts the UserAccount class from the User ontology. It contains five statements in the Turtle syntax, all of which share :UserAccount as the subject.

:UserAccount a owl:Class ;
    rdfs:comment "an individual set of credentials."@en ;
    rdfs:label "User"@en ;
    rdfs:subClassOf owl:Thing .

The first statement :UserAccount a owl:Class states that :UserAccount has the type owl:Class. owl:Class is used to define types of resources.

The next two statements provide labels and comments - essentially annotations - a about :UserAccount. The third statement is standard and simply indicates that a :UserAccount is something that exists in the world

Datatype Property

Datatype Properties describe the types of literal information that can be represented and connected to resources. The following excerpt describes the :hasFullName property, which represents the concept of a user's display name.

:hasFullName
    a owl:DatatypeProperty ;
    rdfs:comment "and extended name or description, used only for display purposes"@en ;
    rdfs:label "has full name"@en ;
    rdfs:domain :UserAccount ;
    rdfs:range xsd:string .

The first statement is similar to what we saw before, but this time it indicates that :hasFullName is a DatatypeProperty. The comment and label fulfill the same role as in the prior example.

The last two statements :hasFullName rdfs:domain :UserAccount and :hasFullName rdfs:range xsd:string represent constraints on this property. The former states that only :UserAccounts may be the subject of this property. The latter says that the literal object value of this property must be of type string.

Object Property

Object Properties describe relationships between resources. The example below captures the notion of group membership for users in computing systems. Note the use of rdfs:domain and rdfs:range to constrain the valid subject and objects for this predicate.

:memberOfGroup
    a owl:ObjectProperty ;
    rdfs:domain :UserAccount ;
    rdfs:label "is member of Group"@en ;
    rdfs:range :Group ;

File Structure

Each of these sub-ontologies is written to a separate file that shares the same name as the ontology using the Terse RDF Triple Langauge (Turtle) encoding. Thus, the User ontology can be found in user.ttl and the Authentication ontology can be found in authentication.ttl.

Although each file focuses on a specific set of concepts, they are not isolated. At the top of each file, a series of namespaces describe other ontologies from which that sub-ontology uses concepts.

Tools for Reading OWL2 Ontology Files

While OWL2 ontology files are human readable, the Semantic Web community has also developed a wide variety of GUI based tools that can be used to read and edit ontology files. Links to a selection of these tools can be found on the Semantic Web Wiki