69 research outputs found
A Lightweight Stemmer for Gujarati
Gujarati is a resource poor language with almost no language processing tools being available. In this paper we have shown an implementation of a rule based stemmer of Gujarati. We have shown the creation of rules for stemming and the richness in morphology that Gujarati possesses. We have also evaluated our results by verifying it with a human expert
Improving the quality of Gujarati-Hindi Machine Translation through part-of-speech tagging and stemmer-assisted transliteration
Machine Translation for Indian languages is an emerging research area. Transliteration is one such module that we design while designing a translation system. Transliteration means mapping of source language text into the target language. Simple mapping decreases the efficiency of overall translation system. We propose the use of stemming and part-of-speech tagging for transliteration. The effectiveness of translation can be improved if we use part-of-speech tagging and stemming assisted transliteration.We have shown that much of the content in Gujarati gets transliterated while being processed for translation to Hindi language
Sub-word indexing and blind relevance feedback for English, Bengali, Hindi, and Marathi IR
The Forum for Information Retrieval Evaluation (FIRE) provides document collections, topics, and relevance assessments for information retrieval (IR) experiments on Indian languages. Several research questions are explored in this paper: 1. how to create create a simple, languageindependent corpus-based stemmer, 2. how to identify sub-words and which types of sub-words are suitable as indexing units, and 3. how to apply blind relevance feedback on sub-words and how feedback term selection is affected by the type of the indexing unit. More than 140 IR experiments are conducted using the BM25 retrieval model on the topic titles and descriptions (TD) for the FIRE 2008 English, Bengali, Hindi, and Marathi document collections. The major findings are: The corpus-based stemming approach is effective as a knowledge-light
term conation step and useful in case of few language-specific resources. For English, the corpusbased
stemmer performs nearly as well as the Porter stemmer and significantly better than the baseline of indexing words when combined with query expansion. In combination with blind relevance feedback, it also performs significantly better than the baseline for Bengali and Marathi IR.
Sub-words such as consonant-vowel sequences and word prefixes can yield similar or better performance in comparison to word indexing. There is no best performing method for all languages. For English, indexing using the Porter stemmer performs best, for Bengali and Marathi, overlapping 3-grams obtain the best result, and for Hindi, 4-prefixes yield the highest MAP. However, in combination with blind relevance feedback using 10 documents and 20 terms, 6-prefixes for English and 4-prefixes for Bengali, Hindi, and Marathi IR yield the highest MAP. Sub-word identification is a general case of decompounding. It results in one or more index terms for a single word form and increases the number of index terms but decreases their average length. The corresponding retrieval experiments show that relevance feedback on sub-words benefits from
selecting a larger number of index terms in comparison with retrieval on word forms. Similarly, selecting the number of relevance feedback terms depending on the ratio of word vocabulary size to sub-word vocabulary size almost always slightly increases information retrieval effectiveness
compared to using a fixed number of terms for different languages
Crosslingual Retrieval Augmented In-context Learning for Bangla
The promise of Large Language Models (LLMs) in Natural Language Processing
has often been overshadowed by their limited performance in low-resource
languages such as Bangla. To address this, our paper presents a pioneering
approach that utilizes cross-lingual retrieval augmented in-context learning.
By strategically sourcing semantically similar prompts from high-resource
language, we enable multilingual pretrained language models (MPLMs), especially
the generative model BLOOMZ, to successfully boost performance on Bangla tasks.
Our extensive evaluation highlights that the cross-lingual retrieval augmented
prompts bring steady improvements to MPLMs over the zero-shot performance.Comment: In The 1st Bangla Language Processing (BLP) Workshop, held in
conjunction with The Conference on Empirical Methods in Natural Language
Processing (EMNLP), December 202
Improving Search via Named Entity Recognition in Morphologically Rich Languages – A Case Study in Urdu
University of Minnesota Ph.D. dissertation. February 2018. Major: Computer Science. Advisors: Vipin Kumar, Blake Howald. 1 computer file (PDF); xi, 236 pages.Search is not a solved problem even in the world of Google and Bing's state of the art engines. Google and similar search engines are keyword based. Keyword-based searching suffers from the vocabulary mismatch problem -- the terms in document and user's information request don't overlap. For example, cars and automobiles. This phenomenon is called synonymy. Similarly, the user's term may be polysemous -- a user is inquiring about a river's bank, but documents about financial institutions are matched. Vocabulary mismatch exacerbated when the search occurs in Morphological Rich Language (MRL). Concept search techniques like dimensionality reduction do not improve search in Morphological Rich Languages. Names frequently occur news text and determine the "what," "where," "when," and "who" in the news text. Named Entity Recognition attempts to recognize names automatically in text, but these techniques are far from mature in MRL, especially in Arabic Script languages. Urdu is one the focus MRL of this dissertation among Arabic, Farsi, Hindi, and Russian, but it does not have the enabling technologies for NER and search. A corpus, stop word generation algorithm, a light stemmer, a baseline, and NER algorithm is created so the NER-aware search can be accomplished for Urdu. This dissertation demonstrates that NER-aware search on Arabic, Russian, Urdu, and English shows significant improvement over baseline. Furthermore, this dissertation highlights the challenges for researching in low-resource MRL languages
Augmenting Translation Lexica by Learning Generalised Translation Patterns
Bilingual Lexicons do improve quality: of parallel corpora alignment, of newly extracted
translation pairs, of Machine Translation, of cross language information retrieval, among
other applications. In this regard, the first problem addressed in this thesis pertains to
the classification of automatically extracted translations from parallel corpora-collections
of sentence pairs that are translations of each other. The second problem is concerned
with machine learning of bilingual morphology with applications in the solution of first
problem and in the generation of Out-Of-Vocabulary translations.
With respect to the problem of translation classification, two separate classifiers for
handling multi-word and word-to-word translations are trained, using previously extracted
and manually classified translation pairs as correct or incorrect. Several insights
are useful for distinguishing the adequate multi-word candidates from those that are
inadequate such as, lack or presence of parallelism, spurious terms at translation ends
such as determiners, co-ordinated conjunctions, properties such as orthographic similarity
between translations, the occurrence and co-occurrence frequency of the translation
pairs. Morphological coverage reflecting stem and suffix agreements are explored as key
features in classifying word-to-word translations. Given that the evaluation of extracted
translation equivalents depends heavily on the human evaluator, incorporation of an
automated filter for appropriate and inappropriate translation pairs prior to human evaluation
contributes to tremendously reduce this work, thereby saving the time involved
and progressively improving alignment and extraction quality. It can also be applied
to filtering of translation tables used for training machine translation engines, and to
detect bad translation choices made by translation engines, thus enabling significative
productivity enhancements in the post-edition process of machine made translations.
An important attribute of the translation lexicon is the coverage it provides. Learning
suffixes and suffixation operations from the lexicon or corpus of a language is an extensively
researched task to tackle out-of-vocabulary terms. However, beyond mere words
or word forms are the translations and their variants, a powerful source of information
for automatic structural analysis, which is explored from the perspective of improving
word-to-word translation coverage and constitutes the second part of this thesis. In this
context, as a phase prior to the suggestion of out-of-vocabulary bilingual lexicon entries,
an approach to automatically induce segmentation and learn bilingual morph-like units by identifying and pairing word stems and suffixes is proposed, using the bilingual
corpus of translations automatically extracted from aligned parallel corpora, manually
validated or automatically classified. Minimally supervised technique is proposed to enable
bilingual morphology learning for language pairs whose bilingual lexicons are highly
defective in what concerns word-to-word translations representing inflection diversity.
Apart from the above mentioned applications in the classification of machine extracted
translations and in the generation of Out-Of-Vocabulary translations, learned bilingual
morph-units may also have a great impact on the establishment of correspondences of
sub-word constituents in the cases of word-to-multi-word and multi-word-to-multi-word
translations and in compression, full text indexing and retrieval applications
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