Ivelina Nikolova


2019

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Proceedings of the Student Research Workshop Associated with RANLP 2019
Venelin Kovatchev | Irina Temnikova | Branislava Šandrih | Ivelina Nikolova
Proceedings of the Student Research Workshop Associated with RANLP 2019

2018

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Tweety at SemEval-2018 Task 2: Predicting Emojis using Hierarchical Attention Neural Networks and Support Vector Machine
Daniel Kopev | Atanas Atanasov | Dimitrina Zlatkova | Momchil Hardalov | Ivan Koychev | Ivelina Nikolova | Galia Angelova
Proceedings of The 12th International Workshop on Semantic Evaluation

We present the system built for SemEval-2018 Task 2 on Emoji Prediction. Although Twitter messages are very short we managed to design a wide variety of features: textual, semantic, sentiment, emotion-, and color-related ones. We investigated different methods of text preprocessing including replacing text emojis with respective tokens and splitting hashtags to capture more meaning. To represent text we used word n-grams and word embeddings. We experimented with a wide range of classifiers and our best results were achieved using a SVM-based classifier and a Hierarchical Attention Neural Network.

2017

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Mining Association Rules from Clinical Narratives
Svetla Boytcheva | Ivelina Nikolova | Galia Angelova
Proceedings of the International Conference Recent Advances in Natural Language Processing, RANLP 2017

Shallow text analysis (Text Mining) uses mainly Information Extraction techniques. The low resource languages do not allow application of such traditional techniques with sufficient accuracy and recall on big data. In contrast, Data Mining approaches provide an opportunity to make deep analysis and to discover new knowledge. Frequent pattern mining approaches are used mainly for structured information in databases and are a quite challenging task in text mining. Unfortunately, most frequent pattern mining approaches do not use contextual information for extracted patterns: general patterns are extracted regardless of the context. We propose a method that processes raw informal texts (from health discussion forums) and formal texts (outpatient records) in Bulgarian language. In addition we use some context information and small terminological lexicons to generalize extracted frequent patterns. This allows to map informal expression of medical terminology to the formal one and to generate automatically resources.

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Proceedings of the Student Research Workshop Associated with RANLP 2017
Venelin Kovatchev | Irina Temnikova | Pepa Gencheva | Yasen Kiprov | Ivelina Nikolova
Proceedings of the Student Research Workshop Associated with RANLP 2017

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Identification of Risk Factors in Clinical Texts through Association Rules
Svetla Boytcheva | Ivelina Nikolova | Galia Angelova | Zhivko Angelov
Proceedings of the Biomedical NLP Workshop associated with RANLP 2017

We describe a method which extracts Association Rules from texts in order to recognise verbalisations of risk factors. Usually some basic vocabulary about risk factors is known but medical conditions are expressed in clinical narratives with much higher variety. We propose an approach for data-driven learning of specialised medical vocabulary which, once collected, enables early alerting of potentially affected patients. The method is illustrated by experimens with clinical records of patients with Chronic Obstructive Pulmonary Disease (COPD) and comorbidity of CORD, Diabetes Melitus and Schizophrenia. Our input data come from the Bulgarian Diabetic Register, which is built using a pseudonymised collection of outpatient records for about 500,000 diabetic patients. The generated Association Rules for CORD are analysed in the context of demographic, gender, and age information. Valuable anounts of meaningful words, signalling risk factors, are discovered with high precision and confidence.

2016

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SUper Team at SemEval-2016 Task 3: Building a Feature-Rich System for Community Question Answering
Tsvetomila Mihaylova | Pepa Gencheva | Martin Boyanov | Ivana Yovcheva | Todor Mihaylov | Momchil Hardalov | Yasen Kiprov | Daniel Balchev | Ivan Koychev | Preslav Nakov | Ivelina Nikolova | Galia Angelova
Proceedings of the 10th International Workshop on Semantic Evaluation (SemEval-2016)

2015

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Proceedings of the Student Research Workshop
Irina Temnikova | Ivelina Nikolova | Alexander Popov
Proceedings of the Student Research Workshop

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Voltron: A Hybrid System For Answer Validation Based On Lexical And Distance Features
Ivan Zamanov | Marina Kraeva | Nelly Hateva | Ivana Yovcheva | Ivelina Nikolova | Galia Angelova
Proceedings of the 9th International Workshop on Semantic Evaluation (SemEval 2015)

2014

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Sublanguage Corpus Analysis Toolkit: A tool for assessing the representativeness and sublanguage characteristics of corpora
Irina Temnikova | William A. Baumgartner Jr. | Negacy D. Hailu | Ivelina Nikolova | Tony McEnery | Adam Kilgarriff | Galia Angelova | K. Bretonnel Cohen
Proceedings of the Ninth International Conference on Language Resources and Evaluation (LREC'14)

Sublanguages are varieties of language that form “subsets” of the general language, typically exhibiting particular types of lexical, semantic, and other restrictions and deviance. SubCAT, the Sublanguage Corpus Analysis Toolkit, assesses the representativeness and closure properties of corpora to analyze the extent to which they are either sublanguages, or representative samples of the general language. The current version of SubCAT contains scripts and applications for assessing lexical closure, morphological closure, sentence type closure, over-represented words, and syntactic deviance. Its operation is illustrated with three case studies concerning scientific journal articles, patents, and clinical records. Materials from two language families are analyzed―English (Germanic), and Bulgarian (Slavic). The software is available at sublanguage.sourceforge.net under a liberal Open Source license.

2013

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51st Annual Meeting of the Association for Computational Linguistics Proceedings of the Student Research Workshop
Anik Dey | Sebastian Krause | Ivelina Nikolova | Eva Vecchi | Steven Bethard | Preslav I. Nakov | Feiyu Xu
51st Annual Meeting of the Association for Computational Linguistics Proceedings of the Student Research Workshop

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Enriching Patent Search with External Keywords: a Feasibility Study
Ivelina Nikolova | Irina Temnikova | Galia Angelova
Proceedings of the International Conference Recent Advances in Natural Language Processing RANLP 2013

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Closure Properties of Bulgarian Clinical Text
Irina Temnikova | Ivelina Nikolova | William A. Baumgartner | Galia Angelova | K. Bretonnel Cohen
Proceedings of the International Conference Recent Advances in Natural Language Processing RANLP 2013

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Proceedings of the Student Research Workshop associated with RANLP 2013
Irina Temnikova | Ivelina Nikolova | Natalia Konstantinova
Proceedings of the Student Research Workshop associated with RANLP 2013

2012

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Unified Extraction of Health Condition Descriptions
Ivelina Nikolova
Proceedings of the NAACL HLT 2012 Student Research Workshop

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Automatic Analysis of Patient History Episodes in Bulgarian Hospital Discharge Letters
Svetla Boytcheva | Galia Angelova | Ivelina Nikolova
Proceedings of the Demonstrations at the 13th Conference of the European Chapter of the Association for Computational Linguistics

2011

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Proceedings of the Second Student Research Workshop associated with RANLP 2011
Irina Temnikova | Ivelina Nikolova | Natalia Konstantinova
Proceedings of the Second Student Research Workshop associated with RANLP 2011

2009

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Proceedings of the Student Research Workshop
Irina Temnikova | Ivelina Nikolova | Natalia Konstantinova
Proceedings of the Student Research Workshop

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New Issues and Solutions in Computer-aided Design of MCTI and Distractor Selection for Bulgarian
Ivelina Nikolova
Proceedings of the Workshop Multilingual resources, technologies and evaluation for central and Eastern European languages

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Extraction and Exploration of Correlations in Patient Status Data
Svetla Boytcheva | Ivelina Nikolova | Elena Paskaleva | Galia Angelova | Dimitar Tcharaktchiev | Nadya Dimitrova
Proceedings of the Workshop on Biomedical Information Extraction