deletions | additions       diff --git a/The_ontology_based_approach_to__.tex b/The_ontology_based_approach_to__.tex  index 58e271d..c64e525 100644  --- a/The_ontology_based_approach_to__.tex  +++ b/The_ontology_based_approach_to__.tex 
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1st stage: search for fragment of semantic net which is relevant to search query. The search is performed using inference engine on the base of semantic rules defined in the ontology as a set of Horn clauses. To implement this stage the semantic rules were formulated for parametrized search on the following parameters: preferred language; outcome learner competencies; mastering level of competences; synonymy of the terms in subject domain.  2nd stage: redefining subnet ${O}_{R}$. obtained at the first stage subnet.  To implement this stage the semantic rules were formulated to search the additional resources on the base of current learner competencies, and search the auxiliary resources, as well as the rules for defining the logical links between learning resources in personal collection. Auxiliary resources are the resources which are not included in the set of additional resources because of too long learning sequence but these resources can help to get the missing competences which are not provided by the set of additional resources. The developed set of semantic rules allows to create the personal learning collection in accordance with the learning outcomes, current knowledge level and other preferences of the learner. This collection includes relations between the learning resources to manage the learning process. To represent the ontology reasoning rules for learning resources retrieval and integration we used SWRL language. SWRL extends the OWL-DL and is based on first-order predicate calculus that allows to represent the reasoning rules as a set of Horn clauses. \section{Software Architecture. Implementation Aspects}  To create the personal learning collections using the proposed ontologies and method, it is necessary to use appropriate software tools, providing the logic reasoning on ontologies (reasoning engines). To implement the logical reasoning the reasoning engine RacerPro (Racer Systems GmbH and Co. KG, Germany) was used. This engine supports the ontologies described with OWL language and reasoning rules described in SWRL. It also can work as server with both DIG (DL Implementors Group) interface and TCP/IP interface with internal queries language nRQL. DIG is a application interface to interact with the reasoning engine that also allows to work with OWL-ontologies and interact with other software tools like ontologies editor Protégé. However this interface has some restrictions, including impossibility to work with SWRL reasoning rules, so the TCP/IP interface was used to implement the SWRL-reasoning.