Ontology evolution is a complex problem. In our work, we focus on issues related to change management, particularly consistency maintenance and we present in this paper, an overview of Change Management Patterns (CMP) that we have defined to model the three dimensions change, inconsistency and resolution alternative. Modelling these patterns and the links between them, helps to propose an automated process guiding and controlling change application while maintaining consistency of the evolved ontology. Change management depends closely on the ontology representation model, we focus on OWL language and we consider change impact on logical consistency as specified in OWL DL layer.
In this paper, we present an overview of OWL Change Management Patterns (CMP) that we have defined. The goal of pattern-centered modelling is to offer for each of the three dimensions: change, inconsistency and resolution alternative, different levels of abstraction and to establish links between them (Fig 1).
Change Management Patterns (CMP) are proposed as a solution looking for invariances in change management that repeatedly appear when evolving ontologies. They classify categories of changes based on OWL model, categories of logical inconsistencies considering OWL DL constraints and categories of inconsistency resolution alternatives. Links between CMP help determining inconsistencies that could be potentially caused by a type of change and alternatives that possibly resolve a kind of inconsistency and thus providing an automated process for change management.
Cause potentially 0..*
Inconsistency 0..* Pattern
Resolved potentially by 0..* 0..*
Change patterns categorize changes and define formally their signification, their scope and their potential implications. They cover OWL basic changes and a first core of composed changes. Change pattern components are: - Involved entities corresponding to conceptual primitives of OWL; - Arguments including all necessary parameters to implement the change. Argument content varies depending on change type and involved entities; - Constraints (preconditions) to satisfy so that change can be applied without affecting the logical consistency of the ontology.
Example1. Let’s consider a basic change pattern of adding a sub-class:
Inconsistency pattern components are: - The IDs of all entities implicated directly or indirectly in a logical inconsistency; - The IDs of entities involved in the inconsistency; - Axioms involved in the inconsistency.
Example 2. Let’s take the basic change example (Example 1) and suppose that the constraint is not satisfied, a possible corresponding disjointness inconsistency pattern can be described as follow: An alternative pattern represents an additional change to apply so that a logical inconsistency can be resolved. It is described as a basic or composed change and it inherits change pattern properties (Fig 1). Other information can also enrich alternative pattern description such as preconditions to satisfy before choosing an alternative pattern as a resolution.
Example 3. Let’s reconsider the basic change example (Example 1), the possible alternative patterns for disjointness inconsistency caused by this change (Example 2) can be described as follow:
In this paper we present OWL Change Management Patterns modelling the three dimensions: change, inconsistency and resolution alternative and links between them. The defined patterns cover OWL DL basic changes, a sub-set of composed changes and a first core of logical inconsistencies and of alternatives that could resolve them. Acknowledgments. Researches reported in this paper are founded by the French National Research Agency ANR, as a part of the project DAFOE: Differential and Formal Ontology Editor.