356 research outputs found
Ontology Learning from Text: An Overview
No full textBuitelaar P, Cimiano P, Magnini B. Ontology Learning from Text: An Overview. In: Buitelaar P, Cimiano P, Magnini B, eds. Ontology Learning from Text: Methods, Evaluation and Applications. Frontiers in Artificial Intelligence and Applications. Vol 123. Amsterdam: IOS Press; 2005: 3-12
Processing of Object Oriented Dialogues
No full textIn this paper we introduce object oriented dialogues (OODs), a subclass of dialogues where the communicative goal is just the retrieval of information about objects in a particular domain. OODs allow a number of computational simplifications which make them attractive for many information access applications. Starting point for this approach was the TAMIC-P prototype system, which will be briefly presented. Finally, OODs are well suited to be represented as graphic object (e.g. folders and documents), easily guiding the user through the discourse structure and at the same time through parts of the underlying knowledge base: in this way typical problems of discourse ambiguity and domain opacity can be overcom
Toward a Robust Processing of Information-Seeking Dialogues
No full textThe main assumption of this paper is that the interpretation of information-seeking dialogues is mainly a domain driven process, where much of the knowledge necessary for their processing can be derived from the Domain Model represantation. Following this line, some discourse structure and the recovering from error situations, are all addressed building a semantic dialogue tree which mirrors the Domain Model structure. The algorithm we propose relies on three steps: (i) first a logical form is built for a single turn, whose clauses are grouped according to their functional role in the user request; (ii) then a dialogue chain for a single turn exploiting the semantic relations among the nodes is derived from the logical form; (iii) finally, the overall dialogue tree is searched for the positions where the chain can be best appended or merged
Learning Taxonomic Relations from Heterogeneous Sources of Evidence
No full textCimiano P, Pivk A, Schmidt-Thieme L, Staab S. Learning Taxonomic Relations from Heterogeneous Sources of Evidence. In: Buitelaar P, Cimiano P, Magnini B, eds. Ontology Learning from Text: Methods, Evaluation and Applications. Frontiers in Artificial Intelligence; 123. Amsterdam: IOS Press; 2005: 59-73
Open Domain Question/Answering on the WEB
No full textThis paper presents a question/answering system for searching the web. The system accepts natural language questions in Italian and returns as answer a ranked list of document passages together with the URL of the whole document. Three crucial aspects related to the web scenario have been investigated: the linguistic expansion of the query, the optimization of the search boolean expression, the evaluation of the results
Recent Advancements in Human Language Technology in Italy
No full textThis paper presents significant advancements in Human Language Technology fostered by Italian researchers in the last years. We report recent results in the following research directions: Distributional Semantics (i.e. the COMPOSES project), Multilingual Word Sense Disambiguation (the MultiJEDI project), Textual Semantic Inferences (the EXCITEMENT project), and Computer Assisted Translation (the MATECAT project). Key aspects that are common to such research initiatives include the fact that they are funded by the European Commission, under different grants, after having passed a very selective international competition; that they are led by Italian researchers, this way showing both the prominent role and the maturity of the Italian community on the international scene; and that they are currently running, indicating that the research topics of the projects are in the mainstream of Computational Linguistics
Opposition Relations among Verb Frames
No full textIn this paper we propose a scheme for annotating opposition relations among verb frames in lexical resources. The scheme is tested on the T-PAS resource, an inventory of typed predicate argument structures for Italian, conceived for both linguistic research and computational tasks. After discussing opposition relations from a linguistic point of view and listing the tags we decided to use, we report the results of the experiment we performed to test the annotation scheme, in terms of interannotation agreement and linguistic analysis of annotated data
Characterization of the velocity fields generated by flow initialization in the CFD simulation of multiphase flows
No full textRecent improvements in numerical algorithms for Eulerian-based CFD simulations of multiphase flows can now recover the exact balance between the pressure and surface tension terms within the momentum equation. This has led to the minimization of the so called "spurious velocities": unphysical flows appearing at interfaces when using implementations of the Continuum Surface Force technique to model surface tension forces. Nevertheless, non-null velocity fields are still observed in the proximity of interfaces despite the absence of external forces, and it will be shown here that they can still considerably influence the accuracy of two-phase flow simulations. This study demonstrates that the evolution of these velocity fields is due to the generation of a capillary wave at the beginning of the simulation. This arises from the inability of the surface tension algorithm to evaluate a constant interface curvature from the initial color function field, although this is obtained by mapping an exact circumference on the computational grid, which then generates an initial perturbation that evolves as a capillary wave. A linear stability analysis of a two-dimensional circular static droplet subjected to initial small amplitude perturbations is here developed and compared with the results of CFD simulations to corroborate this thesis. This methodology provides a novel insight on the nature and behavior of spurious currents and their influential parameters, and it yields results which are not only in line with previous observations but also unify some contrasting trends reported in the literature. It is observed that the velocity magnitude induced by the capillary wave scales with the surface tension coefficient and the inverse of the fluid density and droplet radius. Furthermore, it decreases when refining the computational mesh only if die interface curvature estimations converge to the exact value, while otherwise showing the opposite trend. (C) 2016 Elsevier Inc. All rights reserved.LTC
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