Alistair Plum


2021

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Text Preprocessing and its Implications in a Digital Humanities Project
Maria Kunilovskaya | Alistair Plum
Proceedings of the Student Research Workshop Associated with RANLP 2021

This paper focuses on data cleaning as part of a preprocessing procedure applied to text data retrieved from the web. Although the importance of this early stage in a project using NLP methods is often highlighted by researchers, the details, general principles and techniques are usually left out due to consideration of space. At best, they are dismissed with a comment “The usual data cleaning and preprocessing procedures were applied”. More coverage is usually given to automatic text annotation such as lemmatisation, part-of-speech tagging and parsing, which is often included in preprocessing. In the literature, the term ‘preprocessing’ is used to refer to a wide range of procedures, from filtering and cleaning to data transformation such as stemming and numeric representation, which might create confusion. We argue that text preprocessing might skew original data distribution with regard to the metadata, such as types, locations and times of registered datapoints. In this paper we describe a systematic approach to cleaning text data mined by a data-providing company for a Digital Humanities (DH) project focused on cultural analytics. We reveal the types and amount of noise in the data coming from various web sources and estimate the changes in the size of the data associated with preprocessing. We also compare the results of a text classification experiment run on the raw and preprocessed data. We hope that our experience and approaches will help the DH community to diagnose the quality of textual data collected from the web and prepare it for further natural language processing.

2020

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RGCL at SemEval-2020 Task 6: Neural Approaches to DefinitionExtraction
Tharindu Ranasinghe | Alistair Plum | Constantin Orasan | Ruslan Mitkov
Proceedings of the Fourteenth Workshop on Semantic Evaluation

This paper presents the RGCL team submission to SemEval 2020 Task 6: DeftEval, subtasks 1 and 2. The system classifies definitions at the sentence and token levels. It utilises state-of-the-art neural network architectures, which have some task-specific adaptations, including an automatically extended training set. Overall, the approach achieves acceptable evaluation scores, while maintaining flexibility in architecture selection.

2019

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Toponym Detection in the Bio-Medical Domain: A Hybrid Approach with Deep Learning
Alistair Plum | Tharindu Ranasinghe | Constantin Orasan
Proceedings of the International Conference on Recent Advances in Natural Language Processing (RANLP 2019)

This paper compares how different machine learning classifiers can be used together with simple string matching and named entity recognition to detect locations in texts. We compare five different state-of-the-art machine learning classifiers in order to predict whether a sentence contains a location or not. Following this classification task, we use a string matching algorithm with a gazetteer to identify the exact index of a toponym within the sentence. We evaluate different approaches in terms of machine learning classifiers, text pre-processing and location extraction on the SemEval-2019 Task 12 dataset, compiled for toponym resolution in the bio-medical domain. Finally, we compare the results with our system that was previously submitted to the SemEval-2019 task evaluation.

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RGCL-WLV at SemEval-2019 Task 12: Toponym Detection
Alistair Plum | Tharindu Ranasinghe | Pablo Calleja | Constantin Orăsan | Ruslan Mitkov
Proceedings of the 13th International Workshop on Semantic Evaluation

This article describes the system submitted by the RGCL-WLV team to the SemEval 2019 Task 12: Toponym resolution in scientific papers. The system detects toponyms using a bootstrapped machine learning (ML) approach which classifies names identified using gazetteers extracted from the GeoNames geographical database. The paper evaluates the performance of several ML classifiers, as well as how the gazetteers influence the accuracy of the system. Several runs were submitted. The highest precision achieved for one of the submissions was 89%, albeit it at a relatively low recall of 49%.