1,239 research outputs found
A Survey of Paraphrasing and Textual Entailment Methods
Paraphrasing methods recognize, generate, or extract phrases, sentences, or
longer natural language expressions that convey almost the same information.
Textual entailment methods, on the other hand, recognize, generate, or extract
pairs of natural language expressions, such that a human who reads (and trusts)
the first element of a pair would most likely infer that the other element is
also true. Paraphrasing can be seen as bidirectional textual entailment and
methods from the two areas are often similar. Both kinds of methods are useful,
at least in principle, in a wide range of natural language processing
applications, including question answering, summarization, text generation, and
machine translation. We summarize key ideas from the two areas by considering
in turn recognition, generation, and extraction methods, also pointing to
prominent articles and resources.Comment: Technical Report, Natural Language Processing Group, Department of
Informatics, Athens University of Economics and Business, Greece, 201
Automatic Discovery and Ranking of Synonyms for Search Keywords in the Web
Search engines are an indispensable part of a web user's life. A vast majority of these web users experience difficulties caused by the keyword-based search engines such as inaccurate results for queries and irrelevant URLs even though the given keyword is present in them. Also, relevant URLs may be lost as they may have the synonym of the keyword and not the original one. This condition is known as the polysemy problem. To alleviate these problems, we propose an algorithm called automatic discovery and ranking of synonyms for search keywords in the web (ADRS). The proposed method generates a list of candidate synonyms for individual keywords by employing the relevance factor of the URLs associated with the synonyms. Then, ranking of these candidate synonyms is done using co-occurrence frequencies and various page count-based measures. One of the major advantages of our algorithm is that it is highly scalable which makes it applicable to online data on the dynamic, domain-independent and unstructured World Wide Web. The experimental results show that the best results are obtained using the proposed algorithm with WebJaccard
On the Feasibility of Automated Detection of Allusive Text Reuse
The detection of allusive text reuse is particularly challenging due to the
sparse evidence on which allusive references rely---commonly based on none or
very few shared words. Arguably, lexical semantics can be resorted to since
uncovering semantic relations between words has the potential to increase the
support underlying the allusion and alleviate the lexical sparsity. A further
obstacle is the lack of evaluation benchmark corpora, largely due to the highly
interpretative character of the annotation process. In the present paper, we
aim to elucidate the feasibility of automated allusion detection. We approach
the matter from an Information Retrieval perspective in which referencing texts
act as queries and referenced texts as relevant documents to be retrieved, and
estimate the difficulty of benchmark corpus compilation by a novel
inter-annotator agreement study on query segmentation. Furthermore, we
investigate to what extent the integration of lexical semantic information
derived from distributional models and ontologies can aid retrieving cases of
allusive reuse. The results show that (i) despite low agreement scores, using
manual queries considerably improves retrieval performance with respect to a
windowing approach, and that (ii) retrieval performance can be moderately
boosted with distributional semantics
Automatic Discovery of Word Semantic Relations
In this paper, we propose an unsupervised methodology to automatically discover pairs of semantically related words by highlighting their
local environment and evaluating their semantic similarity in local and global
semantic spaces. This proposal di®ers from previous research as it tries to take
the best of two different methodologies i.e. semantic space models and information extraction models. It can be applied to extract close semantic relations,
it limits the search space and it is unsupervised
Cross-language Ontology Learning: Incorporating and Exploiting Cross-language Data in the Ontology Learning Process
Hans Hjelm. Cross-language Ontology Learning:
Incorporating and Exploiting Cross-language Data in the Ontology Learning Process.
NEALT Monograph Series, Vol. 1 (2009), 159 pages.
© 2009 Hans Hjelm.
Published by
Northern European Association for Language
Technology (NEALT)
http://omilia.uio.no/nealt .
Electronically published at
Tartu University Library (Estonia)
http://hdl.handle.net/10062/10126
An EM Algorithm for Context-Based Searching and Disambiguation with Application to Synonym Term Alignment
PACLIC 23 / City University of Hong Kong / 3-5 December 200
Adversarial Propagation and Zero-Shot Cross-Lingual Transfer of Word Vector Specialization
Semantic specialization is the process of fine-tuning pre-trained
distributional word vectors using external lexical knowledge (e.g., WordNet) to
accentuate a particular semantic relation in the specialized vector space.
While post-processing specialization methods are applicable to arbitrary
distributional vectors, they are limited to updating only the vectors of words
occurring in external lexicons (i.e., seen words), leaving the vectors of all
other words unchanged. We propose a novel approach to specializing the full
distributional vocabulary. Our adversarial post-specialization method
propagates the external lexical knowledge to the full distributional space. We
exploit words seen in the resources as training examples for learning a global
specialization function. This function is learned by combining a standard
L2-distance loss with an adversarial loss: the adversarial component produces
more realistic output vectors. We show the effectiveness and robustness of the
proposed method across three languages and on three tasks: word similarity,
dialog state tracking, and lexical simplification. We report consistent
improvements over distributional word vectors and vectors specialized by other
state-of-the-art specialization frameworks. Finally, we also propose a
cross-lingual transfer method for zero-shot specialization which successfully
specializes a full target distributional space without any lexical knowledge in
the target language and without any bilingual data.Comment: Accepted at EMNLP 201
- …