Enhancing Conceptual Description through Resource Linking and Exploration of Semantic Relations (2019)

Abstract: The paper presents current efforts towards linking two large lexical semantic resources – WordNet and FrameNet – to the end of their mutual enrichment and the facilitation of the access, extraction and analysis of various types of semantic and syntactic information. In the second part of the paper, we go on to examine the relation of inheritance and other semantic relations as represented in WordNet and FrameNet and how they correspond to each other when the resources are aligned. We discuss the implications with respect to the enhancement of the two resources through the definition of new relations and the detailisation of conceptual frames.

## introduction the first part of the paper outlines the principles and procedures of aligning wordnet and framenet. the focus is on wordnet as the main lexical-semantic structure (the verbal domain, in particular), which we aim at enhancing with richer linguistic description from framenet and verbnet. the second part of the paper proposes an analysis of the correspondences between the frame-to-frame relations in framenet and the synset-to-synset relations in wordnet. the aim is two-fold: (a) from a theoretical perspective, to provide insights into the scope and definition of overlapping or corresponding relations and the relational structure of the two resources, to establish similarities and discrepancies that may come from different semantic construal or from errors; (b) from an applied perspective, to provide directions for the mutual enhancement and improvement of (i) the relational structure of the two resources; (ii) the accuracy of the frame assignment based on the theoretical observations. the contribution of the paper consists in: this work is a key part of ongoing research on defining a conceptual framework for encoding semantic relations between verb and noun synsets based on a detailed conceptual representation of verbs and the identification of semantic classes of nouns satisfying the selectional restrictions imposed on frame elements in the verb's frame. after a brief discussion of related work (section 2), we outline the alignment between wordnet and framenet (section 3) based on existing mappings and procedures for their enhancement and expanding. section 4 focuses on the theoretical and practical aspects of semantic relations in framenet and how they are reflected (with respective semantic relations) within wordnet. section 5 sketches the implications from these observations, while (section 6) focuses on the role of this research in the context of other ongoing research. ## related work one of the main directions of development of semantic resources is finding ways of uniting their strengths through integrating them and exploiting their features in a complementary way. mapping of existing semantic resources has been undertaken in a number of works (cf. section 3.1). another line of research in the development and enhancement of the interconnected resources is explicitly linking and generalising existing, but unrelated information in them. a poorly studied direction of research has been the exploration and use of the internal structure of these resources towards their mutual enhancement. one area of research along these lines has been the extension of frame relations by using information from word-net. @xcite propose a supervised model for enriching framenet's relational structure through predicting new frame-to-frame relations using structural features from the existing framenet network, information from the wordnet relations between synsets, and corpus-collected lexical associations. @xcite have employed features of both relational structures to develop an algorithm for assigning framenet frames to wordnet synsets by transferring the relational knowledge for pairs of related synsets to matching lexical units and frames in framenet. an interesting theoretical and practical issue arising from the mapping of the 'building blocks' of the two resources is how the underlying relational structures relate and correspond to each other, how they can be mapped to each other, and further explored. in the second part of this paper, we have attempted to tackle this issue. ## aligning wordnet and framenet our work relies on two main resources -word-net (wn) and framenet (fn), and employ verb-net (vn) as a complementary resource in some tasks related to alignment and verification. we use wordnet @xcite as the basic lexical resource. fn @xcite represents conceptual structures (frames) which describe particular types of objects, situations, etc. along with their participants, or frame elements @xcite . frames are then assigned to lexical units (lus), e.g. the verb mature is assigned the frame aging with the description 'an entity is undergoing a change in age typically associated with some deterioration or change in state'. framenet is internally structured using a set of relations, which are discussed in section 4. the verbnet @xcite classes represent formations of verbs with shared semantic and syntactic properties and be-haviour organised in a shallow hierarchy. ## theoretical and practical aspects of semantic relations within framenet reflected in wordnet fn and wn each have its own relational structure which is based on conceptual relations between language units (wn) or conceptual representations (fn). the wn structure is by far the richer in types and instances of relations; in addition to the conceptual relations it comprises lexical relations, derivational relations and some other relations. although the relations in the two resources have different number and scope, at least part of them are grounded in similar universal assumptions which leads to partial overlap, depending on their definition and the specific information in the resources. for instance, there is a clear correspondence between the inheritance relation in framenet and the hypernymy relation in wordnet, to the extent that both represent a modelling of the is-a relation @xcite , or between the causativity relation (fn) and the causes relation (wn). figure 1 presents the process of linking wn and fn. in what follows, we are going to explore how the fn frame-to-frame relations translate into wn relations (when they do) and to outline the main trends in the correspondence between relations in the two resources. the core part of the data to be examined are pairs or longer chains of wn synsets such that: (a) are related through a given wn relation, and (b) are assigned fn frames, which are (c) related through a particular fn relation. the main wn relation to be considered is hypernymy, which is the principal tree structure organising relation in the resource. we take into account both direct hypernymy (direct relation between a parent and a child node) and indirect hypernymy (where the hypernym is not a parent of the hyponym but there are intermediate parents between them). other relations that emerge from the studied data are: antonymy, also see, causes, verb group, as well as some distant shared hypernyms (i.e. the synsets are in the same tree). below we present the definition and theoretical grounding of fn relations @xcite , along with the observations about their correspondence with wn relations. ## implications from the observations the main conclusions that we can make based on the observations so far are: the success or failure of this activity (the outcome) may be indicated. nb: this frame should be compared to the scrutiny frame, in which the primary focus is on the ground; https://framenet2.icsi.berkeley.edu/fnreports/data/ frameindex.xml?@xmath0, and perspective on, although in a limited way. wn inheritance is implemented through the hypernymy-hyponymy relation. the comparison between the two structures sheds light on the nature of inheritance and hypernymy, especially in the ways it may diverge from the notion of subsumption. especially interesting are the cases of inverted relations as they may point to errors in assignment or to a variability in semantic construal. towards the consistent representation of causativity, we suggest: (a) linking pairs of senses in corresponding causative and inchoative or stative trees, such as the causative and inchoative change trees (the roots synsets are themselves related through the causes relation); (b) transferring the causes relation to relevant lus and frames. ## conclusion and future work the alignment between wordnet and framenet at the lexical level (literals within wordnet synsetslexical units within frames) offers limited coverage and shows some inconsistencies in the repre-sentation of semantic relations. the expansion of the coverage relies on: the understanding of the relational structure of both resources and exploring the possibility of identifying the frames relevant to certain synsets (based on inheritance and other semantic relations); defining new frames and synsets in order to provide consistency in the representation of relations, etc. the verification of the resources as well as their alignment and mutual enhancement can be based on automatic consistency checks of inheritance (both strong, e.g. inheritance, and weak, e.g. relations such as using, perspective, subframe) and on paying special attention to cases with inverted inheritance (frame f 1 , assigned to synset s 1 , is inherited by frame f 2 , assigned to synsets s 2 , but within wordnet s 2 is more general than s 1 ). further exploration of inheritance can yield more (ir)regularities which may facilitate the enhancement of the resources. this work is an integral part of our research on defining a conceptual framework for encoding semantic relations between verbs (as represented in synsets) and relevant sets of noun synsets to the end of creating a relationally densely populated semantic network. in particular, the study of inheritance and the remaining relations in fn and how they translate into wn relations enables us: (i) to formulate procedures for exploring the relational structure of the resources towards increasing the coverage of the mapping between fn frames and wn synsets based on these relations; (ii) to define more rigid and clear-cut conceptual classes of verbs on the basis of the enhanced mapping of conceptual frames; (iii) to undertake the building of a rich relational structure through defining relations between verbs belonging to particular frames and sets of nouns with particular semantic properties (as reflected in wn subtrees, ontological categories, etc.) corresponding to key frame elements in the verb's frame. the last task is sensitive to the precision and scope of the conceptual description and is thus dependent on the validation, extension and enhancement of the assignments.