Ontology Supported Frame Classification (2022)

Abstract: We present BulFrame – a web-based system designed for creating, editing, validating and viewing conceptual frames. A unified theoretical model for the formal presentation of Conceptual frames is offered, which predetermines the architecture of the system with which the data is processed. A Conceptual frame defines a unique set of syntagmatic relations between verb synsets representing the frame and noun synsets expressing the frame elements. Thereby, the notion of Conceptual frame combines semantic knowledge presented in WordNet and FrameNet and builds upon it. The main difference with FrameNet semantic frames is the definition of the sets of nouns that can be combined with a given verb. This is achieved by an ontological representation of noun semantic classes. The framework is built and evaluated with Conceptual frames for Bulgarian verbs.

## introduction there are many rich semantic resources (mainly for english but also for other languages) that include different types of semantic information: wordnet @xcite , framenet @xcite , verbnet @xcite , propbank @xcite , ontonotes @xcite , pattern dictionary of english verbs @xcite , yago @xcite , babelnet @xcite , verbatlas @xcite , synsemclass @xcite , among others. bulframe 1 is a web-based system designed for creating, editing, validating and viewing conceptual frames. a unified theoretical model for the formal presentation of conceptual frames is offered, 1 https:\dcl.bas.bg/bulframe/ which predetermines the architecture of the system with which the data is processed. in this regard, several fundamental theoretical models focused on verb semantics have been taken into account -among the most famous research in this field are charles fillmore's theory of frame semantics @xcite , the description of verb classes and possible alternations by beth levin @xcite , the concept of representation of verb frames in framenet @xcite and others. some of the main advantages of both resources (wordnet and framenet) with regard to the conceptual description of the predicate -argument structure are complemented and upgraded to expand wordnet with conceptual frames that represent verb predicate-argument syntagmatic relations. the main advantages of wordnet for semantic analysis focused on introducing conceptual frames are: a) the large number of concepts organized in a semantic network and b) the grouping of concepts in semantic classes according to their general meaning. the main advantages of framenet for implementing conceptual frames are: a) the extensive description of semantic knowledge about an event type and its participants and b) the linking of semantic frames with semantic relations @xcite . the paper is organized as follows: we begin with a brief introduction to the notion of conceptual frame in section 2. in section 3 we present the design of the bulframe system. section 4 is dedicated to the linguistic interpretation of conceptual frames with a special focus on the ontology of semantic classes of nouns. finally, related work (section 5), conclusions and future directions of our work (section 6) are presented. our main contributions are: (a) identification of verbs that evoke a particular framenet semantic frame; (b) detailed ontological representation of semantic classes of noun synsets; (c) specification of frame elements relevant to the expression of syntagmatic relations; (d) assigning the frame elements with noun semantic classes or a combination of classes ensuring the words' compatibility in bulgarian; (e) definition of conceptual frames depicting semantics of bulgarian verbs. ## the notion of conceptual frames conceptual frames are abstract structures that define the semantic and syntactic compatibility between verb predicates and noun arguments. a particular conceptual frame is: associated with a semantic class that expresses its general semantic properties; represented by a set of verbs organized in the wordnet synonym sets, and described by a set of frame elements. the verbs in the same frame can be one or several: linked between each other with lexical relations (synonymy, antonymy) and/or hierarchical relations (hypernymy, troponymy, entailment). the conceptual frame elements roughly correspond to the framenet core elements; however, there is no one-to-one correspondence between framenet semantic frames and conceptual frames (because of some differences in conceptualization in different languages and because of differences between the two theoretical representations) @xcite . each conceptual frame element is associated with a set of nouns that are compatible with the verb predicate. again, the set could contain a single noun or several nouns linked between each other with lexical relations (synonymy, antonymy) and/or hierarchical relations (hypernymy, hyponymy). the association between the frame (verb synsets) and its elements (noun synsets) can be explicitly introduced in wordnet by means of syntagmatic relations. if more than one noun synset can express the frame element (which is the usual case), the syntagmatic relation links the verb synset with the top-most noun synset of the hierarchy grouping nouns with the same semantic properties (semantic class). the diversity in the compatibilities between representatives of verb classes and noun classes drives the necessity for a detailed ontology of semantic classes of nouns. we can generalize that a conceptual frame defines a unique set of syntagmatic relations between: ## linguistic interpretation of conceptual frames conceptual frames represent the lexical meaning and morphological features of (bulgarian) verbs which actually predict the syntactic realization and semantic combinability of their arguments (core frame elements), which are also the subject of description @xcite . the structure of a conceptual frame consists of the following sections: lexical, morphological, and frame (syntactic and semantic) section. ## related work framenet is the most famous language resource that contains lexical and conceptual knowledge @xcite . framenet can be viewed as a semantic network (or a set of small semantic nets), whose nodes indicate the semantic frames and whose arcs represent semantic relations between frames. for the purposes of the presented research, the following information is employed: the sets of verb lexical units related to semantic frames, the inheritance relation between semantic frames, and the description of core and peripheral frame elements and their semantic types. the fram-net annotation is mostly used for automatic role labelling while we offer the definition of noun sets compatible with verbs from a particular conceptual frame (and such approach offers much more training data for automatic processing). framenets for languages other than english are being developed, including for bulgarian. verbatlas is a relatively new, hand-crafted lexical-semantic resource, whose goal is to bring together wordnet verbal synsets into semanticallycoherent frames @xcite . the frames define a common, prototypical argument structure, while at the same time provide new conceptspecific information. verbatlas also offers an explicit, cross-frame set of semantic roles linked to selectional preferences expressed in terms of word-net synsets, and is the first resource enriched with semantic information about implicit, shadow and default arguments. the main difference between the verbatlas and the presented framework is that the verbatlas selectional preferences are too general, similarly to the semantic types of core elements in framenet, in comparison to the extensive semantic information provided within the bul-frame to ensure accurate noun-to-verb compatibility. some efforts to describe bulgarian frame lexicon were also shown, and we believe our work draws on the best approaches in the field. ## conclusion and future work the presentation of conceptual frames of bulgarian verbs provides opportunities for the enrichment of already existing resources (wordnet and framenet) with new semantic information (in the direction of completeness and structural expansion), developing a detailed ontology of the semantic classes of nouns and linking it to the hierarchical structure of wordnet and the frame elements of framenet. the main characteristic of the approach we have taken is the manner of connecting framenet and wordnet -not by assigning frames to synsets, i.e., not in the usual way, but by showing which word-net subtrees are suitable to take one or another syntactic position in which a frame element is realized. the morpho-syntactic features that are specific for bulgarian are shown in detail; selective restrictions are specified so that the resource can be used for automatic prediction of semantic roles in any text. as future work, we plan to take full advantage of the semantic features available in bulframe, such as wide-coverage selectional preferences and verb level grammatical information, by employing them in semantic role labelling tasks.