4,242 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
Incorporating source-language paraphrases into phrase-based SMT with confusion networks
To increase the model coverage, sourcelanguage paraphrases have been utilized to boost SMT system performance. Previous
work showed that word lattices constructed from paraphrases are able to reduce out-ofvocabulary words and to express inputs in different ways for better translation quality.
However, such a word-lattice-based method suffers from two problems: 1) path duplications in word lattices decrease the capacities for potential paraphrases; 2) lattice decoding in SMT dramatically increases the search space and results in poor time efficiency. Therefore, in this paper, we adopt word confusion networks as the input structure to carry source-language paraphrase information. Similar to previous work, we use word lattices to build word confusion networks for merging of duplicated paths and faster decoding. Experiments are carried out on small-, medium- and large-scale English–
Chinese translation tasks, and we show that compared with the word-lattice-based method, the decoding time on three tasks is reduced significantly (up to 79%) while comparable
translation quality is obtained on the largescale task
Using same-language machine translation to create alternative target sequences for text-to-speech synthesis
Modern speech synthesis systems attempt to produce
speech utterances from an open domain of words. In some situations, the synthesiser will not have the appropriate units to pronounce some words or phrases accurately but it still must attempt to pronounce them. This paper presents a hybrid machine translation and unit selection speech synthesis system. The machine translation system was trained with English as the source and target language. Rather than the synthesiser only saying the input text as would happen in conventional synthesis systems, the synthesiser may say an alternative utterance with the same
meaning. This method allows the synthesiser to overcome the
problem of insufficient units in runtime
Comparison and Adaptation of Automatic Evaluation Metrics for Quality Assessment of Re-Speaking
Re-speaking is a mechanism for obtaining high quality subtitles for use in
live broadcast and other public events. Because it relies on humans performing
the actual re-speaking, the task of estimating the quality of the results is
non-trivial. Most organisations rely on humans to perform the actual quality
assessment, but purely automatic methods have been developed for other similar
problems, like Machine Translation. This paper will try to compare several of
these methods: BLEU, EBLEU, NIST, METEOR, METEOR-PL, TER and RIBES. These will
then be matched to the human-derived NER metric, commonly used in re-speaking.Comment: Comparison and Adaptation of Automatic Evaluation Metrics for Quality
Assessment of Re-Speaking. arXiv admin note: text overlap with
arXiv:1509.0908
Paraphrasing and Translation
Paraphrasing and translation have previously been treated as unconnected natural lan¬
guage processing tasks. Whereas translation represents the preservation of meaning
when an idea is rendered in the words in a different language, paraphrasing represents
the preservation of meaning when an idea is expressed using different words in the
same language. We show that the two are intimately related. The major contributions
of this thesis are as follows:• We define a novel technique for automatically generating paraphrases using
bilingual parallel corpora, which are more commonly used as training data for
statistical models of translation.• We show that paraphrases can be used to improve the quality of statistical ma¬
chine translation by addressing the problem of coverage and introducing a degree
of generalization into the models.• We explore the topic of automatic evaluation of translation quality, and show that
the current standard evaluation methodology cannot be guaranteed to correlate
with human judgments of translation quality.Whereas previous data-driven approaches to paraphrasing were dependent upon
either data sources which were uncommon such as multiple translation of the same
source text, or language specific resources such as parsers, our approach is able to
harness more widely parallel corpora and can be applied to any language which has
a parallel corpus. The technique was evaluated by replacing phrases with their para¬
phrases, and asking judges whether the meaning of the original phrase was retained
and whether the resulting sentence remained grammatical. Paraphrases extracted from
a parallel corpus with manual alignments are judged to be accurate (both meaningful
and grammatical) 75% of the time, retaining the meaning of the original phrase 85%
of the time. Using automatic alignments, meaning can be retained at a rate of 70%.Being a language independent and probabilistic approach allows our method to be
easily integrated into statistical machine translation. A paraphrase model derived from
parallel corpora other than the one used to train the translation model can be used to
increase the coverage of statistical machine translation by adding translations of previously unseen words and phrases. If the translation of a word was not learned, but
a translation of a synonymous word has been learned, then the word is paraphrased and its paraphrase is translated. Phrases can be treated similarly. Results show that
augmenting a state-of-the-art SMT system with paraphrases in this way leads to significantly improved coverage and translation quality. For a training corpus with 10,000
sentence pairs, we increase the coverage of unique test set unigrams from 48% to 90%,
with more than half of the newly covered items accurately translated, as opposed to
none in current approaches
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