КОНВЕРТАЦІЯ ФОРМАТІВ ЗБЕРІГАННЯ ГРАФОВИХ БАЗ ДАНИХ І ЇЇ РОЛЬ В ОНТОЛОГІЧНОМУ ІНЖИНІРИНГУ НА ПРИКЛАДІ СИСТЕМИ СУПРОВОДЖЕННЯ РЕАБІЛІТАЦІЇ

Graph databases seam like an eff ective tool for presenting concepts of a particular subject area and the relationships exist in it. Such representations are known as ontologies. Graph databases could be also acceptable for other cases, especially for data with a natural graph structure, for example: description of interaction between organizations and/or persons, transport, telecommunications, language structures, etc. Graph databases of an ontological type have been widely used in the development of an intelligent information-analytical system for rehabilitation monitoring processes (TISP). In particular, such sections as «White Book», «Gastroenterology», «Ischemic Heart Disease», «Medical Law», «Physical Rehabilitation», etc. were presented in this way.There exist many options for presenting and storing graph databases, since, one of the most common and universal formats for ontologies storing is OWL, in particular with RDF/XML syntax. There are also such formats as «Manchester OWL Syntax», «OWL Functional Syntax», «Turtle» and some others. The conversion possibility between these formats is implemented and available in such applications as «Protégé», or through the API of online services. But the problem is the lack of an accessible, but powerful and convenient graphic editor for ontology schemes that works with named formats. Nevertheless, creating a complex ontology scheme in, for example, the built-in “Protégé” editor is a complex and inconvenient process. Moreover, the possibilities of constructing an ontograph in “Protégé” are rather narrow. The same is also true for numerous online ontology editors.A convenient tool for visual development, viewing and editing of onto-graphs is the KIT «Polyhedron» (also known as «Graph Editor») developed at the Institute of Cybernetics of the National Academy of Sciences of Ukraine. The combination of a friendly visual interface, wide functionality and easy going makes KIT «Polyhedron» almost one of the most advanced tools in modern ontologicalengineering. But the feature of KIT «Polyhedron» is a very specifi c format for the graphs storing in XML-fi les. This format (in following – the «Graph Editor» format) is perceived exclusively by the KIT “Polyhedron”. However, OWL, which is acceptable for many graphical databases as the primary or intermediate format for storing and downloading data, is not currently supported in the “Polyhedron” KIT. Thus, the task was to create a converter that translates XML-fi les from the format «Graph Editor» to OWL in RDF/XML syntax, also in the opposite direction.The analysis is carried out to study the data storage peculiarities for ontological graphs in “Graph Editor” format, structure of corresponding XML-fi les and ways of the most complete representation of both main and auxiliary (technical) information by available options of RDF/XML syntax. On the other hand, methods have been developed to represent standard OWL entities and constructs using Graph Editor. A technique has been developed for program meta-representation of data read from the corresponding OWL-entities and methods of their serialization in OWL or XML-“Graph Editor” format have been implemented. The corresponding software system wasbuilt in the form of an online service. The nodes of the ontological graph constructed in the KIT “Polyhedron” during conversion can be moved to the standard OWLentities like classes, properties or named individuals. If the node type is not explicitly specifi ed, it becomes a class by default. It is also possible to represent non-typed vertices by other OWL types, taking into account specifi c types of relationships (if any). Non-typed relationships could optionally be interpreted as “Subclass” or “Default”. A special attention is paid to the representation of the data contained in the nodes and links of the graph. By default, they become a label, but if a type is specifi ed, they can become any of the “annotations” for the corresponding OWL entity. From these links, specifi c technical ontology object properties are formed that connect&nbsp;the corresponding nodes, to which the data are to be attached in the form of a label or other annotations. It is possible to create various, both standard (subclass, equivalence, diff erence, etc.) and arbitrary links between the nodes of the ontological graph, if they are specifi ed in the source fi le. Attachments are represented by links through tag attributes that indicate their own ID and the ID of the parent data tag.The inverse conversion creates onto-graph nodes of the corresponding types from the classes, properties, and named individuals of the ontology classes, except for the technical ones, which are used in this case to restore the structure of the corresponding data. Tags that contain technical information are not converted to linked data, but are used to initialize the node characteristics (shape, color, position, etc.). The developed program for conversion was used for the translation to the OWL-format of the ontology on the “White Book”, which using RDFlib works as a part of the dialog subsystem TISP. A number of other medical ontologies, which are the parts of the TISP project, have also been successfully converted to OWL format. Analysis of the results showed no loss of information during both direct and reverse conversion. The fi les are successfully accepted by RDF/XML parsers, including “Protégé”, RDFlib, Neo4j (downloading OWL ontology using the Neosemantics plug-in), and is able to be subjected to formal SPARQL queries to information extraction. Transferring the resulting OWL fi le to Neo4j to the ontology, the Cypher query language can also be used. A convenient software tool has been created for translating ontological graphs created using the powerful visual ontological engineering system KIT “Polyhedron” to OWL-ontologies in RDF/XML syntax. This signifi cantly expands the practical applicability of the ontologies created in this way, allows them to be successfully implemented into reference systems, information collection and processing systems, using standard tools for RDF/XML format processing. The reverse conversion feature allows you to use the “Polyhedron” KIT to view and edit third-party OWL ontologies acquired on the Internet or otherwise.