Reference
Essence Kernel Ontology
OWL formalization of the OMG Essence 2.0 Kernel (Jacobson et al. 2013). Defines the universal elements of software engineering: Alphas (things to work with), Activity Spaces (things to do), and Competencies (capabilities required). BFO-grounded.
- Namespace
https://schema.bra0.org/essence-kernel#- Prefix
ess:- Version
- 1.0.0
- License
- <https://www.omg.org/legal/ipr.htm>
- Created
- 2026-04-03
- Classes
- 7
- Properties
- 9
- Source
ontologies/foundation/essence-kernel.ttl
Classes (7)
| URI | Label | Description | Superclass |
|---|
| ess:ActivitySpace | Activity Space | An essential thing to do. Activity spaces represent the challenges a team faces and the kinds of activities they perform. They are ordered in progression chains within each area of concern. | bfo:0000015, ess:KernelElement |
| ess:Alpha | Alpha | An essential thing to work with. Alphas represent the key concerns that a team must attend to in any software engineering endeavor. Each alpha has a linear sequence of states representing its progress. | bfo:0000031, ess:KernelElement |
| ess:AlphaState | Alpha State | A specific named state in an alpha's progression. An alpha is in exactly one state at a time. States are individuals, not types — 'Identified' is a specific state, not a class of things. | bfo:0000031 |
| ess:AreaOfConcern | Area of Concern | A discrete area focusing on a specific aspect of software engineering. Essence defines exactly 3: Customer, Solution, Endeavor. | --- |
| ess:Competency | Competency | A key capability required to carry out software engineering work. A competency is a disposition — a realizable capacity of an agent that can be exercised at different levels. | bfo:0000016, ess:KernelElement |
| ess:CompetencyLevel | Competency Level | A level of proficiency at which a competency can be exercised. Essence defines 5 levels: Assists, Applies, Masters, Adapts, Innovates. | bfo:0000031 |
| ess:KernelElement | Kernel Element | Root class for all elements of the Essence Kernel: the universal, essential elements of software engineering. | bfo:0000001 |
Object Properties (8)
| URI | Label | Domain | Range |
|---|
| ess:advancesAlpha | advances alpha | rdfs:Resource | ess:Alpha |
| ess:advancesState | advances state | rdfs:Resource | ess:AlphaState |
| ess:atLevel | at level | rdfs:Resource | ess:CompetencyLevel |
| ess:belongsToArea | belongs to area | ess:KernelElement | ess:AreaOfConcern |
| ess:exercisesCompetency | exercises competency | rdfs:Resource | ess:Competency |
| ess:hasState | has state | ess:Alpha | ess:AlphaState |
| ess:predecessorOf | predecessor of | rdfs:Resource | rdfs:Resource |
| ess:stateOf | state of | ess:AlphaState | ess:Alpha |
Datatype Properties (1)
| URI | Label | Domain | Range |
|---|
| ess:stateOrder | state order | ess:AlphaState | xsd:integer |
SPARQL example
PREFIX ess: <https://schema.bra0.org/essence-kernel#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT ?class ?label ?comment
WHERE {
?class a owl:Class ;
rdfs:label ?label .
OPTIONAL { ?class rdfs:comment ?comment }
FILTER(STRSTARTS(STR(?class), STR(ess:)))
}
ORDER BY ?label