Papers by Christos Christodoulopoulos
Simple Large-scale Relation Extraction from Unstructured Text (L18-1)
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| Challenge: | Knowledge-based question answering relies on the availability of facts, most of which cannot be found in structured sources. |
| Approach: | They propose a method for creating distant (weak) supervision labels for training a large-scale RE system by decoupling the model architecture from the feature design of a state-of-the-art neural network system. |
| Outcome: | The proposed method performs on par with the state-of-the-art model with similar features at 75x reduction in training time. |
WebIE: Faithful and Robust Information Extraction on the Web (2023.acl-long)
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| Challenge: | Existing closed IE datasets are built using Wikipedia, but they have limitations when applied to web domains. |
| Approach: | They propose to annotate 25K triples from WebIE through crowdsourcing and introduce mWebIE, a translation of the annotated set in four other languages. |
| Outcome: | The proposed model trains on 1.6M sentences from the English Common Crawl corpus and includes negative examples to better reflect the data on the web. |
Gold Standard Annotations for Preposition and Verb Sense with Semantic Role Labels in Adult-Child Interactions (C18-1)
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| Challenge: | Existing corpus of child-directed speech augments existing corpus for semantic role labels . sense and number of arguments were open to multiple interpretations due to rapidly changing discourse . |
| Approach: | They propose to augment an existing corpus of child-directed speech to provide supervised learning of semantic role labels. |
| Outcome: | The resulting corpus is a gold standard for supervised learning of semantic role labels in child-directed speech. |
Debiasing knowledge graph embeddings (2020.emnlp-main)
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| Challenge: | Existing methods to train knowledge graph embeddings to be neutral to sensitive attributes such as gender have been shown to increase training time by a factor of eight or more. |
| Approach: | They propose a method where all embeddings are trained to be neutral to sensitive attributes such as gender by default using an adversarial loss. |
| Outcome: | The proposed method reduces training time by eightfold and improves accuracy. |
Hidden Biases in Unreliable News Detection Datasets (2021.eacl-main)
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| Challenge: | Recent studies show that automatic unreliable news detection models only use the article itself without resorting to fact-checking mechanisms. |
| Approach: | They propose to use a simple model as a difficulty/bias probe instead of a complex one . they observe a significant drop in accuracy for all models tested in a clean split . |
| Outcome: | The proposed model can achieve good performance by memorizing site-label mapping instead of modeling the real task. |
ReFinED: An Efficient Zero-shot-capable Approach to End-to-End Entity Linking (2022.naacl-industry)
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| Challenge: | Entity linking is the task of recognising mentions of entities in unstructured text documents and linking them to the corresponding entities in a Knowledge Base (KB) the largest public EL dataset is Wikipedia, which covers just 3% of the entities in Wikidata. |
| Approach: | They propose a model which performs mention detection, fine-grained entity typing, and entity disambiguation for all mentions within a document in a single forward pass. |
| Outcome: | The proposed model outperforms state-of-the-art methods on standard datasets by an average of 3.7 F1 and can generalise to large-scale knowledge bases such as Wikidata and zero-shot entity linking. |
FEVER: a Large-scale Dataset for Fact Extraction and VERification (N18-1)
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| Challenge: | 185,445 claims generated by altering sentences from Wikipedia are verified without knowledge of the sentence they were derived from. |
| Approach: | They propose a publicly available dataset for verification against textual sources, FEVER: Fact Extraction and VERification. |
| Outcome: | The proposed dataset achieves 31.87% accuracy on labeling a claim accompanied by the correct evidence, compared to 50.91% if we ignore the evidence. |
Generating Token-Level Explanations for Natural Language Inference (N19-1)
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| Challenge: | Existing methods to generate token-level explanations for NLI on single sentences have not been tested. |
| Approach: | They propose to generate token-level explanations for NLI without explicitly annotating training data. |
| Outcome: | The proposed approach is faster and more accurate than the black-box methods. |
mReFinED: An Efficient End-to-End Multilingual Entity Linking System (2023.findings-emnlp)
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| Challenge: | Existing work assumed that entity mentions were given and skipped the entity mention detection step due to a lack of high-quality multilingual training corpora. |
| Approach: | They propose a bootstrapping mention detection framework that enhances the quality of training corpora. |
| Outcome: | The proposed framework outperforms existing work in the end-to-end MEL task while being 44 times faster. |
Evaluating adversarial attacks against multiple fact verification systems (D19-1)
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| Challenge: | Automated fact verification is progressing due to advances in modeling and availability of large datasets. |
| Approach: | They propose two scoring metrics which take into account the correctness of adversarial instances. |
| Outcome: | The proposed method and paraphrasing method have higher potency and higher resilience than baselines. |
A Relation Extraction Dataset for Knowledge Extraction from Web Tables (2022.coling-1)
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| Challenge: | Existing datasets with relational web-tables are either synthetic, or very small in size. |
| Approach: | They propose to annotate relational web-tables against a human-annotated dataset using crowd sourced annotators from MTurk. |
| Outcome: | The proposed dataset has 50x larger number of column pairs than the existing human-annotated benchmark. |
The FEVER2.0 Shared Task (D19-66)
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| Challenge: | Existing deep neural models are becoming more complex and difficult to understand and characterize their behaviour. |
| Approach: | They present the results of the second Fact Extraction and VERification (FEVER2.0) Shared Task. |
| Outcome: | The proposed task was based on the second Fact Extraction and VERification (FEVER2.0) shared task. |
SWAN: Semantic Watermarking with Abstract Meaning Representation (2026.acl-long)
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Ziping Ye, Gourab Dey, Christos Christodoulopoulos, Charith Peris, Anil Ramakrishna, Weitong Ruan, Aram Galstyan, Kai-Wei Chang, Rahul Gupta, Ninareh Mehrabi
| Challenge: | Existing methods to embed signatures by adjusting token selection preferences during text generation are highly sensitive to paraphrasing and synonyms. |
| Approach: | They propose a framework that embeds watermark signatures into the semantic structure of a sentence using Abstract Meaning Representation (AMR). |
| Outcome: | Empirical evaluation shows SWAN matches state-of-the-art detection performance on unaltered watermarked text while improving robustness against paraphrasing. |
CogCompNLP: Your Swiss Army Knife for NLP (L18-1)
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Daniel Khashabi, Mark Sammons, Ben Zhou, Tom Redman, Christos Christodoulopoulos, Vivek Srikumar, Nicholas Rizzolo, Lev Ratinov, Guanheng Luo, Quang Do, Chen-Tse Tsai, Subhro Roy, Stephen Mayhew, Zhili Feng, John Wieting, Xiaodong Yu, Yangqiu Song, Shashank Gupta, Shyam Upadhyay, Naveen Arivazhagan, Qiang Ning, Shaoshi Ling, Dan Roth
| Challenge: | a corpus-reader module supports popular corpora, feature extraction and annotation modules for semantic and syntactic tasks. |
| Approach: | They propose a library that provides modules to address different challenges . they provide a corpus-reader module that supports popular corpora in the NLP community . |
| Outcome: | The proposed library simplifies the process of design and development of NLP applications by providing modules to address different challenges. |