No abstract

Ontology instance migration is one of the complex and not fully solved problems in knowledge management. A solution is required when the ontology schema evolves in the life cycle and the assertions have to be transferred to the newer version. The problem may become more complex in distributed settings when, for example, several autonomous software entities use and exchange partial assertional knowledge in a domain that is formalized by different though semantically overlapping descriptive theories. Such an exchange is essentially the migration of the assertional part of an ontology to other ontologies belonging to or used by different entities. The paper presents our method and tool for migrating instances between the ontologies that have structurally different but semantically overlapping schemas. The approach is based on the use of the manually coded transformation rules describing the changes between the input and the output ontologies. The tool is implemented as a plug-in for the ProjectNavigator prototype software framework. The article also reports the results of our three evaluation experiments. In these experiments we evaluated the degree of complexity in the structural changes to which our approach remains valid. We also chose the ontology sets in one of the experiments to make the results comparable with the ontology alignment software. Finally we checked how well our approach scales with the increase of the quantity of the migrated ontology instances to the numbers that are characteristic to industrial ontologies. In our opinion the evaluation results are satisfactory and suggest some directions for the future work.

No abstract

Ontology instance migration is one of the challenges in knowledge management. It becomes even more complex in distributed settings when, for example, several autonomous agents use partial assertional knowledge in a domain that is formalized by different though semantically overlapping descriptive theories. Agents exchange instances of their ontologies when cooperate. Such an exchange is essentially the migration of the assertional part of an ontology to other ontologies owned by different agents. The paper presents our method and tool support for migrating instances between different semantically overlapping ontologies. The method is based on the use of manually coded formal rules describing the changes between the input and the output ontologies. The tool to support the process is implemented as a plug-in to Cadence ProjectNavigator software. The main contribution of the paper is in presenting the results of the evaluation of this tool. It reports about the set-up for our evaluation experiments, the metrics used for measuring the quality of instance migration, the ontologies that have been chosen as the experimental data, and the evaluation results. Evaluation results are satisfactory and suggest some directions for the future work.

The article addresses algebraic methods for coloring arbitrary cubic graphs. The results are partially based on the corollaries of the Tait theorem. In the article, the authors propose using a fourth-order Klein group transform in order to formally describe the coloring of a cubic graph. The transition to graph coloring is done by coloring the edges of basis cycles. Overall, the mathematical framework for describing topological graph drawing is presented and formally described in the article. Based on the edge coloring, the formation of colored disks and the mathematical description of the operation of colored disks rotation with subsequent recoloring of the edges are considered. It is shown that the operation of rotating color disks can be represented as a ring sum (addition modulo 2) of cycles. In order to unambiguously describe the representation of colored disks by means of basis cycles, the authors introduce the concept of embeddability of colored disks. For clarity, the authors provide several examples illustrating the application of colored disks rotation operation to concrete cubic graphs. The relation between the system of induced cycles generated by the rotation of graph vertices and the coloring of 2-factors of the cubic graph is established in the present study. It is shown that the ring sum of all cycles included in the colored 2-factors of the graph is an empty set. The article also addresses the issues of coloring non-planar cubic graphs. The relationship between basis cycles and a rim in a non-planar cubic graph and a ring sum of colored 2-factors is explicitly shown in the article. In addition, the relationship between the colored vertex rotation of a plane cubic graph and the closed Heawood paths is revealed and formally described.